JP4388534B2 - Vibration control device for machine tools - Google Patents

Description

  The present invention relates to a machine tool, and relates to a technical means capable of performing highly accurate processing having a good finished surface.

  A machine tool processes a workpiece by relative movement between the workpiece and a blade. In order to perform a highly accurate machining of the finished surface, it is necessary to maintain an accurate relative positional relationship between the workpiece and the blade. Therefore, the structural members of the machine tool are made to have high rigidity so as not to be deformed by an external force, and various considerations are taken so that the external force does not affect the machining accuracy of the workpiece.

  One factor that reduces the finishing accuracy of workpieces is machine tool vibration. Workpieces are usually finished in several steps: roughing, medium machining, and finishing. In rough machining, heavy cutting with a large cutting reaction force is performed, and there is a large error in the shape of the material, so that vibration generated in the machine during machining is large. However, as the intermediate processing and finishing processing progress, the amount of cutting decreases and the cutting reaction force applied to the machine becomes constant, so that the vibration of the machine also decreases. Therefore, machining errors caused by machine vibration during rough machining are removed by subsequent machining, and a processed product with good accuracy can be obtained.

  However, in a machine having a plurality of processing stations in one machine, such as a two-spindle facing lathe, rough processing may be performed at the first processing station and finishing may be performed at the second processing station. For example, in a two-spindle facing lathe, the material supplied by the loader is gripped by the chuck of the first spindle, roughed, transferred to the chuck of the second spindle, and the part gripped by the chuck of the first spindle And finishing. In such a case, the vibration generated in the rough machining on the first main spindle side propagates to the second main spindle side, and the accuracy of the finishing process performed on the second main spindle side is reduced.

  In order to avoid a decrease in workpiece finishing accuracy due to machine vibration, increase the inertial mass on the machine side to reduce the amplitude, or install a vibration isolating member that absorbs vibration between the vibration source and the processing station. It is possible to intervene. However, the former is not a preferable measure because it unnecessarily increases the size of the machine tool and increases the machine cost. In the latter case, the buffering function is a function that is difficult to be compatible with the rigidity required for the machine tool, and thus it is difficult to adopt it in practice.

  In view of the above problems, the present invention is a machine tool having a plurality of processing stations in which roughing and finishing may be performed simultaneously on the same machine, and vibration on the roughing side propagates to the finishing side. Thus, it is an object of the present invention to provide technical means that can effectively prevent a reduction in finishing accuracy.

  The vibration damping device for a machine tool according to the first aspect of the present application provides a vibration damping device for a machine tool having a first machining station 11 for rough machining and a second machining station 12 for finishing machining on the same machine. The apparatus includes a vibration detector 21 fixed to a constituent member of the first processing station, and a vibrator 25 fixed to a work holding member or a blade holding member of the second station. The above-mentioned problems are solved by providing a vibration damping device for a machine tool that controls the drive current value of the vibrator 25 based on an output signal.

  The vibration damping device for a machine tool according to the invention of claim 2 of the present application includes a first machining station 11 for performing rough machining and a second machining station 12 for performing finishing on the same machine, and the second machine station. The machining station includes a workpiece holding member and a blade holding member, a feed motor that changes a relative positional relationship between the workpiece and the blade, and a servo control device that controls the feed motor. A machine comprising a vibration detector 21 fixed to a component of the first machining station, and correcting a position signal applied to a servo control device of the second machining station based on an output of the vibration detector. By providing a vibration damping device for a machine, the above problems are solved.

  In the invention of this application, by applying vibrations in the opposite phase to the vibration detected by the vibration detector 21 to the workpiece holding table and the tool holding table on the finishing process side, the mutual vibrations are offset to each other. Suppresses blade vibration. Since the vibration generated during rough machining has the largest amplitude in the direction in which the cutting reaction force acts, the vibration detector 21 is fixed so as to detect the vibration in the direction, and the vibrator 25 is set so as to cancel the vibration. The position signal of the servo control device that is mounted or controlling the position in the direction is corrected.

  According to the present invention, in a machine tool including a plurality of processing stations that perform roughing and finishing in parallel, it is possible to remove vibration that affects the finishing accuracy of a workpiece. Since the vibration detector is fixed at a position close to the vibration source, the timing for detecting the vibration is accelerated and the amplitude of the detected vibration is large, which is advantageous in terms of signal detection and response speed.

  Although it is actually difficult to make the vibrator or servo controller compatible with the fine vibration detected by the vibration detector, the vibration of the machine is usually the main vibration with a large amplitude, and the frequency is higher than this. In most cases, vibration with small amplitude is superimposed, so if you control the vibrator or servo controller to control the main vibration, the deterioration of finishing accuracy due to vibration will be greatly reduced. it can.

  Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are schematic plan views showing the first embodiment and the second embodiment, respectively, and both show an example in which the present invention is applied to a two-spindle opposed lathe. The two-spindle-facing lathe shown in the figure includes a first headstock 2 that is substantially integrated with the bed 1 (see FIG. 3), and a first turret that moves in the Z-axis (main-axis direction) and X-axis (cutting direction of cutting tool) directions. A tool post 3, a second spindle stock 4 that moves in the Z-axis direction facing the first spindle stock, and a second turret tool post 5 that moves in the X-axis direction are provided. The first main shaft 6 and the second main shaft 7 are pivotally supported by the first main shaft base 2 and the second main shaft base 4, respectively, and are located on the same axis line, and the first chuck 8 and the second chuck are opposed to each other. 9 is installed.

  FIG. 3 is a schematic front view showing a two-spindle opposed lathe equipped with a gantry type loader. The loader's portal-shaped frame 52 is mounted on a lathe bed 1 and includes a carriage 54 that travels along an upper girder 53 thereof. The carriage 54 is provided with a vertical arm 55 that moves up and down, and a hand 56 that grips a workpiece is provided at the lower end of the arm.

  Hereinafter, the operation of the two-spindle opposed lathe equipped with a loader will be briefly described with reference to FIGS. The loader conveys the workpiece by horizontally moving the carriage 54 and raising and lowering the arm 55 and supplies the material to the first chuck 8. In the first machining station 11 constituted by the first spindle stock and the first turret tool post, rough machining and finishing of the portion gripped by the second chuck 9 are performed. Next, after the second head stock 4 moves to the first head stock side and delivers the work from the first chuck 8 to the second chuck 9, the second head stock moves backward, and then the second head stock and the second turret cutter are moved. The rough machining of the part gripped by the first chuck 8 and the entire finishing process are performed at the second machining station 12 constituted by a table. After the workpiece is transferred to the second chuck 9, the next workpiece is supplied from the loader to the first chuck 8, and the processing at the first processing station 11 and the processing at the second processing station 12 are performed in parallel. During that time, the loader picks up the next work and waits. The workpiece that has been processed at the second processing station 12 is transferred to a loader or an unloader (not shown) and carried out of the machine.

  As can be understood from the above description of operation, in a machine tool having a plurality of machining stations such as a two-spindle facing lathe, when finishing is performed at one machining station, the machining is performed at the other machining station. The vibration due to the roughing is generated, or the vibration accompanying the movement of the loader is generated.

  FIG. 1 is a view showing a first embodiment of the present invention. In this example, the vibration detector 21 is fixed to the first spindle stock 2, and the vibrator 25 is fixed to the second turret tool post 5. Bidirectional arrows a and b written in the vicinity of the vibration detector 21 and the vibration generator 25 indicate the vibration detection direction and the vibration direction, respectively. In this example, both are the X-axis direction, that is, the cutting direction of the blade. . A signal from the vibration detector 21 is given to the vibrator 25 via the arithmetic circuit 31 and the driver 32. The arithmetic expression of the arithmetic circuit 31 preliminarily measures the vibration of the first headstock 2 and the vibration of the second headstock 4 and the second turret tool post 5 when roughing is performed at the first processing station 11. Determine based on their correlation.

  FIG. 2 is a view showing a second embodiment of the present invention, and the vibration detector 21 is fixed to the first head stock 2 so as to detect vibration in the X-axis direction, similarly to the first embodiment. . The signal of the vibration detector 21 is input to the NC device 33, and the NC device 33 servo-controls the servo motor 28 that drives the second turret tool post 5 in the X-axis direction based on the drive signal corrected by the signal from the vibration detector 21. Output to the device 34. That is, in the second embodiment, the signal of the vibration detector 21 is given to the X-axis feed motor 28 of the second turret tool post 5 via the NC device 33 and the servo control device 34. What correction is to be performed by the NC device 33 can be determined using a method similar to the method of obtaining the arithmetic expression of the first embodiment.

  As described above, according to the invention of this application, it is possible to avoid the influence of the vibration on the first machining station side on the workpiece that is finished in the second machining station.

Schematic plan view of the first embodiment Schematic plan view of the second embodiment Schematic front view of a two-spindle facing lathe equipped with a loader

Explanation of symbols

2 1st headstock 3 1st tool rest 4 2nd headstock 5 2nd tool rest 6 1st spindle 7 2nd spindle
11 First processing station
12 Second processing station
21 Vibration detector
25 Exciter
28 Servo motor

Claims (2)

  A vibration control device for a machine tool including a first machining station for rough machining and a second machining station for finishing machining on the same machine, wherein the vibration detector is fixed to a component of the first machining station. (21) and a vibrator (25) fixed to the work holding member or blade holding member of the second station, and based on the output signal of the vibration detector (21), A vibration damping device for a machine tool, characterized by controlling a drive current value.   A first processing station that performs roughing and a second processing station that performs finishing are provided on the same machine, and the second processing station has a relative positional relationship between the workpiece holding member and the blade holding member, and the workpiece and the blade. A vibration control device for a machine tool comprising a feed motor to be changed and a servo control device for controlling the feed motor, comprising a vibration detector (21) fixed to a component of the first processing station. A vibration damping device for a machine tool, wherein a position signal given to the servo control device of the second processing station is corrected based on the output of the vibration detector.

Images