JPH06182647A - Precision machine tool - Google Patents

Abstract

PURPOSE:To simplify the origin setting between feed shaft mechanisms in a precision machine tool having an interference feed shaft mechanism in addition to basic feed shaft mechanisms. CONSTITUTION:An interference feed shaft mechanism 60 arranged to interfere with basic feed shaft mechanisms in three perpendicular axis directions are provided in addition to them to suppress the erroneous displacement of the first and second feed action sections 12, 14 during the mechanical machining process via the mutual feed displacement between them. The feed screw shaft 62 of the interference feed shaft mechanism 60 is formed with an air feed screw a nut 64 is formed with an air nut, and the basic feed shaft mechanisms can be returned to the original positions when the control of the interference feed shaft mechanism 60 by a control device is released and a brake is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a feed shaft system of 1/100.
Precision machine tools that have a resolution of less than μ and are capable of precisely machining mirror-finishing of workpieces, etc. have been developed and put to practical use in recent years. In addition to the three basic feed axes in the orthogonal three-axis (X, Y, Z) directions for relatively feeding and displacing the two feed operation sections that are held, a tuning fork formed between the two feed operation sections described above. Equipped with an interfering feed shaft mechanism installed between both operating parts to suppress vibration displacement between both operating parts due to cutting reaction force due to the die structure, etc. The present invention relates to a precision machine tool having a structure capable of automatically and easily performing origin setting.

[0002]

2. Description of the Related Art As a precision machine tool of the type described above, a tetrahedral machine tool developed in the UK has already been introduced to Japan, and the applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 63-288.
As disclosed in Japanese Patent No. 644, it has a servo mechanism that determines the relative position of the tool and the work based on the set value, and places both the place as close as possible to the tool and the place as close as possible to the work. For example, an actuator with a servo mechanism is used to connect the distances, and a distance detection sensor that detects the distance between the two locations is provided, and the correction value for the relative position is calculated using the detection values of these distance sensors. Has proposed a precision machine tool having a structure including a control means for feeding back to the servo mechanism, and having an actuator for suppressing error displacement such as vibration displacement due to a tuning fork structure.

In the conventional precision machine tool having the mechanism for suppressing the error displacement as described above, at the time of assembling the precision machine tool, there are three basic feed axis mechanisms and an error displacement suppressing mechanism having an actuator. The respective origin positions are recognized by the control means, and the current position data of the basic feed axis system is continuously retained by, for example, a back-up power source even when the main power source of the machine is cut off. By ensuring the relative data between the error displacement restraint mechanism and the error displacement restraint mechanism, the operation of the precision machine tool can be immediately started when the main power source is connected again.

[0004]

However, according to the structure of the conventional precision machine tool described above, the position of the basic feed shaft mechanism, and hence the tool, can be changed in some circumstances, for example, when the consumption of the backup power supply is not noticed. If the current positions of the held feed motion part and the other feed motion parts that hold the workpiece can no longer be recognized, remove the actuator of the error displacement suppression mechanism, etc., and do the same as during the initial assembly of the machine tool. It is necessary to perform the operation of recognizing the origin position from the beginning, and again the mechanism with a precise structure,
Assembling has a problem that it is extremely troublesome in that it requires a long time and meticulous assembling technology from the viewpoint of maintaining high assembly precision.

Therefore, it is not necessary to continuously maintain the current position of the basic feed shaft mechanism with a backup power source even when the main power source is cut off, and when the main power source is turned on again,
It is desired to provide a precision machine tool equipped with a feed shaft mechanism having a configuration capable of easily performing the origin setting of the three basic feed shaft mechanisms and the error displacement suppression mechanism. Therefore, an object of the present invention is to provide a precision machine tool that can meet such a demand.

[0006]

According to the present invention, there is provided a first feed operation unit having a tool and a work piece to be machined by three basic feed shaft mechanisms which are feed screw mechanisms in the directions of three orthogonal axes using a drive motor as a drive source. An error displacement restraint mechanism for imparting relative displacement between the workpiece and the second feed motion unit to perform machining, and at this time suppresses vibrational error displacement due to a cutting reaction force between the motion units. As at least one interfering feed shaft mechanism, as the feed screw means in the interfering feed shaft mechanism, for example, an air screw shaft and an air nut that are rotationally driven by a servo motor and have a static pressure air layer interposed in a screwing portion. By using a small resistance resistance feed screw consisting of and, when setting the origin, remove the servo motor that drives the feed screw of the interference feed shaft mechanism from the control target of the control means, and Release the motor braking to freely move the air feed screw and air nut, and then return each axis of the basic feed shaft to the home position.After returning to the home position, the current position of the feed screw of the interference feed shaft mechanism By recognizing as the origin position, the origin can be easily set.

That is, according to the present invention, the first operating unit holding the tool and the second operating unit holding the workpiece are X,
Three basic feed shaft mechanisms provided for relative feed displacement along the three orthogonal directions of Y and Z, and the first and second
At least one interfering feed shaft mechanism, which is provided between the moving parts of the above, and is provided for suppressing error displacement of the both working parts due to a cutting reaction force and the like, and which is provided with a small sledge resistance type feed screw means, The drive motors of the three basic feed shaft mechanisms and the drive source motors of the interference feed shaft mechanisms are provided to be driven and controlled via respective motor drive servo circuits according to a predetermined machining program, and the respective drive motors are provided. There is provided a precision machine tool characterized by comprising a control means having a motor braking circuit built in a motor drive servo circuit.

[0008]

According to the above construction, there is no means for holding the data of the current position of the basic feed mechanism when the main power source is cut off, but when the main power source is turned on again, the control means is controlled. First, release only the operation control and brake related to the drive source motor of the interference feed shaft mechanism, then sequentially return each basic feed shaft mechanism to the origin position, and finally, restore the operation control of the interference feed shaft mechanism. Then, by returning to the origin position, the origin can be easily set between the three basic feed axes and the interference feed axis. Less than,
The present invention will be described in more detail according to the embodiments shown in the accompanying drawings.

[0009]

FIG. 1 is a plan view of a precision machine tool according to an embodiment of the present invention, FIG. 2 is a side view of the machine tool, and FIG. 3 is an NC controller constituting a control means and the precision machine shown in FIG. FIG. 4 is a block diagram showing a connection with a drive motor of a machine tool, FIG. 4 is a flow chart showing an operation procedure in an origin position setting mode by the control means, and FIG. 5 is a plan view showing a configuration of a precision machine tool according to another embodiment. It is a figure.

Referring to FIGS. 1 and 2, the machine body of the precision machine tool according to the present embodiment includes a bed 10 which can be installed on the floor surface via a vibration isolator, and the bed 10 is orthogonal to the bed 10. One feed operation unit 1 arranged in the biaxial (X, Y) direction
2 and the other feeding operation unit 14 are provided.

The feeding operation unit 12 (corresponding to the other feeding operation unit described in the claims) has a fixed guide 20 extending in the X-axis direction, and a static pressure bearing means known to the fixed guide 20. The sliding base 22 is attached to the sliding base 22 so that it can be smoothly and stably slid in the X-axis direction. Work table 24 for attaching work workpiece W detachably
Is installed. The X-axis feed mechanism for moving and displacing the slide base 22 in the X-axis direction is a drive motor Mx from a servomotor attached to one end of the fixed guide 20 and an X-axis feed screw rotationally driven by the drive motor Mx. Axis 2
6 and the feed screw shaft 26,
Member 28 that moves in the X-axis direction with respect to the axis of
The nut member 28 is formed integrally with the slide base 22 in effect.

A protrusion 22a is formed at the end of the slide base 22 opposite to the drive motor Mx.
A mounting table 30 is provided so as to be rotatable about the vertical axis with respect to 2a. Then, the nut 6 of the interference feed shaft mechanism, which will be described later, is provided on the upper surface of the mounting table 30.
4 is held. Further, the feeding operation unit 14 (corresponding to one feeding operation unit described in the claims) has a fixed guide 40 extending in the Y-axis direction orthogonal to the X-axis direction, and the fixed guide 40. Similarly, a sliding base 42 is attached, which is held by a well-known aerostatic bearing means so as to have a low resistance, and which can be smoothly and stably slid in the Y-axis direction. A spindle head 44 is integrally attached to the slide base 42 so as to be movable in the Y-axis direction, and a spindle 46 is attached to the spindle head 44 so as to be rotatable around the Y-axis.

The work table 24 to which the work W to be processed is attached is erected by an upright guide in the Z-axis direction (vertical direction in the figure) orthogonal to both the X-axis direction and the Y-axis direction. A structure capable of sliding displacement is provided by driving a Z-axis drive motor including a servo motor (not shown) along 49. That is, the three mutually orthogonal X-axis, X-axis, Y-axis, and Z-axis form three basic feed axis directions, and the feed drive motors Mx, My, Mz in the respective axial directions are formed.
The feed operation is performed by (not shown).

Y for sliding displacement of the slide base 42 in the Y-axis direction
The shaft feed mechanism includes a drive motor My composed of a servo motor attached to one end of the fixed guide 40, and the drive motor M.
The feed screw shaft 48 in the Y-axis direction that is rotationally driven by y
And a nut member 50 that engages with the feed screw shaft 48 and feeds and moves in the Y-axis direction with respect to the axial center of the feed screw shaft 48. Are integrally formed and move in the Y-axis direction together. A protrusion 42a is formed on a side end of the slide base 42, and a mounting table 52 is provided on the protrusion 42a so as to be rotatable about a vertical axis. An interference feed shaft drive motor Mv that rotationally drives a feed screw shaft 62 of an interference feed shaft mechanism, which will be described later, is attached and held on the upper surface of the attachment table 52.

As shown in FIG. 1, in the present embodiment, the work W attached to the work table 24 is machined by a cutting tool such as a diamond tool T mounted on the spindle 46. The main shaft 46 is connected so as to be rotationally driven by the main shaft motor Mp.

According to the basic feed shaft mechanism described above, the slide table 42 having the spindle head 44 and the spindle 46 mounted thereon is moved in the Y-axis direction to hold the work table 24 having the work W to be processed mounted thereon. When the sliding base 22 is moved in the X-axis direction, a relative feed displacement is generated between the tool T and the workpiece W in the two orthogonal directions, and the spindle 46 is held. Since the spindle head 44 has a configuration that slides in the Z-axis direction that is orthogonal to both the X and Y axes, it is possible to machine the workpiece W with the tool T. . However, when the workpiece W is cut by the cutting action of the tool T, the machine bed 1
The sliding bases 22 and 42, which are separated from each other on the upper surface of 0 and are fixedly arranged in an opposed manner, substantially have a tuning fork structure under the action of an external force, and therefore, due to the cutting reaction force acting between them. From the viewpoint of machining with a precision machine having a resolution on the order of 1/100 μ or less, an undesired vibrational relative displacement occurs, which deteriorates the machining accuracy of the workpiece.

Therefore, according to one embodiment of the present invention, in order to suppress the vibrational relative displacement caused by the action of the cutting reaction force or the like due to the above-mentioned tuning fork structure, the sliding bases 22, 42 are arranged. The interfering feed shaft mechanism 60 is provided so as to extend between the two. In other words, the feed screw shaft 26 of the X-axis feed mechanism and the Y-axis feed screw shaft 48 are not arranged in parallel but extend in a direction substantially intersecting with each other, and the feed screw shaft 62 is rotatably driven by the drive motor Mv described above. This feed screw shaft 6
The interfering feed shaft mechanism 60 having the feed nut 64 screwed to the 2 is provided. The interference feed screw shaft 62 and the feed nut 64 are composed of a well-known air screw shaft and air nut in which a frictional resistance is substantially removed by interposing a static pressure air layer therebetween, and drive coupling is performed by a drive motor Mv. When the relationship is released, the feed screw shaft 62 and the feed nut 64 are formed so that the feed operation can be easily caused by a small external force. One end of the interference feed screw shaft 62 is rotatable about the rotation axis of the mounting table 52 described above via the drive motor Mv.
In addition, the interference feed nut 64 is the same as the mounting table 30 described above.
At the same time, the table 30 is configured so as to be rotatable around the axis of rotation.

The feed drive motors Mx, M provided on the machine body side of the precision machine tool having the above-mentioned structure.
As shown in FIG. 3, y, Mz, and Mv are connected to a control device 70 including an NC device that controls a machining operation according to an NC machining program, and the control device 70 includes each drive motor Mx including a servo motor. X-axis, Y-axis, and Z of My, Mz, and Mv, which are well-known servo amplifier circuits
Rotational driving force is transmitted through the shaft and interference shaft driving circuits 72, 74, 76, 78. Of course, the position data of the feed shaft is fed back to the control device 70 from the encoders of the drive motors Mx, My, Mz, Mv. Further, each of the drive circuits 72 to 78 has a built-in braking circuit for braking the corresponding drive motor Mx or the like according to the braking command. A well-known dynamic brake circuit (power generation braking circuit) can be used as such a braking circuit.

Now, in the precision machine having the above-mentioned structure, in the machining process, the main power source is turned on so that the control device 70 composed of the NC device performs basic operations of the feed motion parts 12, 14 etc. in accordance with the machining program. The drive motors Mx to Mz in the feed shaft mechanism are operated and controlled to control the feed operation, and the tool T mounted on the spindle 46 performs precision machining on the workpiece W. At this time,
At the same time, the control device 70 also controls the drive motor Mv of the interference feed shaft mechanism 60 to control the feed operation of the interference feed shaft mechanism 60 in synchronism with the feed operation of the basic feed shaft mechanism so as to move between the tool T and the work W. At the present position of both feed motion parts 12 and 14 due to the cutting reaction force, an error displacement generated between both motion parts 12 and 14 due to the cutting reaction force is prevented, and the machining accuracy of precision machining is maintained with high accuracy. There is.

Here, the interfering feed shaft mechanism 60 with respect to the X, Y, and Z basic feed shaft mechanisms described above includes the latter when the former feed shaft systems are set to the origin position at the time of assembling a precision machine. The interference feed shaft mechanism 60 is also set to the origin position so that the control device 70 recognizes it. As a result, the interference feed shaft mechanism operates in synchronization with the operation of the basic feed shaft mechanism to cause an error displacement. It has a structure that prevents it.

In the thus-assembled precision machine tool, the current positions of the feed motion parts 12 and 14 are always recognized by the control device 70 from the feedback detection signals from the drive motors Mx to Mz, and thus are recognized. Although the operation control of the interference feed shaft mechanism 60 is performed based on the current positions of the feed operation units 12 and 14, for example, when the main power supply is cut off, the feed operation unit 12 by the basic feed shaft mechanism is
It becomes impossible for the control device 70 to recognize the current position of 14. Therefore, when the main power is turned on again, both feed operation units 12 and 14 are returned to the origin position, and at that time, the interference feed shaft mechanism 60 is also recognized to have returned to the origin position. It is necessary to set the origin to restore the matching relationship between the basic feed shaft mechanism such as the X, Y, and Z axes and the interference feed shaft mechanism 60.

According to the present invention, the basic feed shaft mechanism for the X-axis to Z-axis and the interfering feed shaft mechanism 60 by the return to origin as described above.
It is possible to easily perform the origin setting that restores the matching relationship between and. The sequence of this origin setting operation will be described below with reference to the flowchart of FIG.

First, the control device 70 is turned on by turning on the main power again.
Command the origin setting mode. In accordance with this origin return mode command, the control signal path for the drive motor Mv of the interference feed shaft mechanism 60 is invalidated and the braking circuit is also invalidated to release the drive motor Mv from the command and control system by the control device 70. At this time, since the feed screw shaft 62 and the feed nut 64 of the interference feed shaft mechanism 60 are composed of the air screw shaft element and the air nut element, the frictional resistance is extremely small, and therefore, the weak rotation applied from the outside. It is possible to operate by drive action.

Under such a condition, the drive motor Mx of the X-axis feed operation unit 12 is next operated to drive the same feed operation unit 1.
Return 2 to the home position. Further, the drive motor My of the Y-axis feed operation unit 14 is operated to return the same feed operation unit 14 to the original position. Further, the Z-axis feed mechanism is also returned to the origin position if necessary. The origin return operation of each basic feed shaft mechanism is released by the control of the interfering feed shaft mechanism 60, so that the interfering feed shaft mechanism 60 follows the operation without causing any interference, and the origin is easily set. It is possible to return to the position.

Thus, when the basic feed shaft mechanisms are respectively returned to the origin positions, the control device 70 for each of the basic feed shaft mechanisms determines from the drive motors Mx etc. that the current position is the origin position. It is recognized by the feedback detection signal of. When such recognition is confirmed, the interference feed shaft mechanism 60 is returned to the control state from the released state. In other words, by recognizing the current position of the interference feed axis mechanism as the origin position with respect to the current position (origin position) of the basic feed axis mechanism,
The matching relationship of all feed axis systems is restored. When the origin setting is completed in this manner, the current position of the interfering feed shaft mechanism uniquely corresponds to the various positions of the basic feed shaft mechanism described above.
It is possible to carry out precision machining while suppressing the error displacement caused by the cutting reaction force and the like generated by the interference feed shaft mechanism 60.

As is clear from the above description of the embodiment,
According to the present invention, when the matching relationship between the basic feed shaft mechanism of the precision machine and the interfering feed shaft mechanism that suppresses the error displacement between the feed operation units 12 and 14 is lost due to disconnection of the main power source or the like. The origin can be easily set without disassembling the structural elements of the machine even if the basic feed shaft mechanism does not have a means for holding the present position. Then, immediately after the origin is set, the precision machining process can be performed according to the machining program.

In the above embodiment, the feeding operation unit 1
The work W to be processed is mounted and mounted on the 2 side, and the feed operation unit 14
The tool T is attached to the main spindle 46 of the
However, conversely, an appropriate tool base is provided on the feed operation unit 12 side to hold the tool T, and the spindle 46 on the feed operation unit 14 side is provided with a work chuck device. Even when the workpiece W to be machined is mounted and the workpiece W is rotated while the mating tool T is used for cutting, the interfering feed shaft mechanism 60 causes the double feed operation units 12, 1
Needless to say, it is possible to suppress the error displacement due to the cutting reaction force between the four and to perform high precision precision machining. Of course,
When the main power is turned on again after the consistency between the interference feed shaft mechanism 60 and the basic feed shaft mechanism is lost due to the disconnection of the main power supply, the origin setting can be easily performed in the above-described sequence. Needless to say.

FIG. 5 shows the construction of a precision machine tool according to another embodiment of the present invention. In the embodiment shown in FIG. 5,
In addition to the above-mentioned interference feed shaft mechanism 60, another interference shaft feed mechanism 80 is installed between the feed operation parts 12 and 14 of the tuning fork structure. That is, a pair of interfering feed shaft mechanisms 60 and 80 are provided on both sides of the cutting action point between the tool T and the workpiece W so as to suppress the error displacement due to the cutting reaction force of both feed operation units 12 and 14. It is the one.

The interference feed shaft mechanism 80 is composed of an air feed screw that is rotationally driven by a drive motor Mw that is a servo motor, intersects with the X axis direction, and extends in a direction not parallel to the Y axis. It is similar to the interference feed shaft mechanism 60 of the first embodiment described above in that the feed screw shaft 82 and the nut 84 formed of an air nut screwed to the feed screw shaft 82 are provided.

The drive motor Mw is connected to a control device 70 (see FIG. 4) to be operated and controlled, and the feed operation unit 14
Other protrusion 42b provided on the opposite side of the protrusion 42a
The rotary table 52a is pivotally attached to the rotary table 52a. On the other hand, the nut 84 is used for the rotary mount 30.
It is provided in a structure attached to a rotary mount 86 similar to.

According to the precision machine of this embodiment, since the interfering feed shaft mechanisms 60 and 80 are provided as a pair at two positions sandwiching the cutting point of the workpiece W, the feed operation by the basic feed shaft mechanism is performed. In the process of performing the precision cutting process on the workpiece W, the oscillating error displacement due to the cutting reaction force between the two feed operation units 12 and 14 is more effectively suppressed.

Also in this embodiment, when the main power supply is cut off and the data of the current position of the feed operation units 12 and 14 is lost, first, the control device 70 controls both interference feed shaft mechanisms 60 and 80. Is released and the brake is released. In this way, the interference feed shaft mechanism 6
By releasing the control of 0 and 80 and releasing the dynamic Bragg circuit, the basic feed shaft mechanism can be freely moved without receiving the interference of both the interference feed shaft mechanisms 60 and 80. Therefore, next, drive motors Mx to Mz in the X-axis, Y-axis, and Z-axis basic feed shaft mechanisms are respectively
It is possible to easily complete the origin setting by returning to the origin position and recognizing the positions of the interference feed shaft mechanisms 60 and 80 at the time of the return from the feedback signals of the drive motors Mv and Mw. It is similar to the embodiment of.

[0033]

As is apparent from the above description, according to the present invention, a tool is formed by three basic feed shaft mechanisms which are feed screw mechanisms in orthogonal three axial directions using a drive motor composed of a servo motor as a drive source. Machining is performed by applying relative displacement between the first feed motion part having the workpiece and the second feed motion part having the workpiece to be machined. At least one interfering feed shaft mechanism is provided as an error displacement restraining mechanism for restraining an oscillating error displacement, and as a feed screw means in the interfering feed shaft mechanism, for example, a servo motor is rotationally driven and a static pressure is applied to a screwing portion. A servo motor that drives the feed screw of the interfering feed shaft mechanism when setting the origin by using a small resistance resistance feed screw consisting of an air screw shaft and an air nut with an air layer in between. Remove from the control target by the control means,
At the same time, the brake of the same servo motor is released and the air feed screw and air nut are freely movable.In that state, each axis of the basic feed shaft is returned to the home position. By recognizing the current position of the screw as the origin position, the origin can be easily set.

By thus making it possible to easily set the origin of the interference feed shaft mechanism of the precision machine tool, the operability of the precision machine tool can be simplified, and the assembly process can be performed at the manufacturing stage of the machine. Facilitating and, in turn,
It is also possible to reduce the manufacturing cost of precision machine tools. It goes without saying that the precision of precision machining of a precision machine tool having such an interference feed shaft mechanism can be further improved.

[Brief description of drawings]

FIG. 1 is a plan view of a precision machine tool according to an embodiment of the present invention.

FIG. 2 is a side view of the machine tool.

3 is a block diagram showing a connection between an NC control device that constitutes a control means and a drive motor of the precision machine tool shown in FIG. 1. FIG.

FIG. 4 is a flowchart showing an operation sequence in an origin position setting mode by the control means.

FIG. 5 is a plan view showing the configuration of a precision machine tool according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Bed 12 ... Feed motion part 14 ... Feed motion part 20 ... Fixed guide 22 ... Sliding base 24 ... Work table 26 ... Feed screw shaft 28 ... Nut member 30 ... Mounting base 40 ... Fixed guide 42 ... Sliding base 44 ... Spindle head 46 ... Spindle 48 ... Feed screw shaft 50 ... Nut member 60 ... Interference feed shaft mechanism 62 ... Feed screw shaft 64 ... Feed nut 70 ... Control device 72-78 ... Drive circuit 80 ... Other interference feed shaft mechanism Mx-Mz … Drive motor Mv, Mw… Drive motor T… Tool W… Workpiece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Nagaoka 3580, Kobaba, Oshinomura, Minamitsuru-gun, Yamanashi Prefecture FANUC CORPORATION (72) Inventor, Tomohiko Kawai, 3580, Kobaba, Oshinomura, Minamitsuru-gun, Yamanashi Prefecture Local FANUC CORPORATION (72) Inventor Keisuke Imai 3580 Kobaba, Oshinomura, Minamitsuru-gun, Yamanashi Prefecture FANUC CORPORATION

Claims (1)

[Claims] 1. Basics provided for relative feed displacement of one working part holding a tool and the other working part holding a workpiece along triaxial X, Y, Z orthogonal directions. At least one feed shaft mechanism, which is provided between the two operating parts, is provided to suppress an error displacement of the two operating parts due to a cutting reaction force, etc. The interference feed shaft mechanism, the drive motors of the three basic feed shaft mechanisms, and the drive source motor of the interference feed shaft mechanism are provided to be driven and controlled via respective motor drive servo circuits according to a predetermined machining program. A precision machine tool comprising: a control means having a motor braking circuit built in each of the motor drive servo circuits.