Swing prevention device

Abstract

To provide a swing prevention device which can be attached to a turret or a tool spindle and may support an elongated workpiece with constant support force when the elongated workpiece is processed by a CNC lathe or a CNC composite lathe.SOLUTION: A swing prevention device includes: a device main part 21 connected to a turret; a hole part 22 provided at the device main part 21 to allow insertion of an elongated workpiece W; a pair of fixed rollers 23 disposed at an outer edge of the hole part 22; a movable roller 24 disposed at a position facing the pair of fixed rollers 23 in the outer edge of the hole part 22; a slider 25 which moves the movable roller 24 forward or rearward toward the workpiece W; a power transmission mechanism which transmits power applied from the turret to the slider; and a power restriction mechanism which restricts power applied from the power transmission mechanism to the slider 25.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a steady rest device, and more particularly to a steady rest device that can be attached to a turret or tool spindle when machining a long workpiece on a CNC lathe or CNC combined lathe, and that makes it possible to support the long workpiece with a constant supporting force. [Background technology]

[0002] When machining a long workpiece using a CNC lathe (a machine tool capable of lathe machining that is numerically controlled by a computer), if the tip of the long workpiece is not held, it becomes unstable and the tip will vibrate, making machining difficult. In response to this, a lathe equipped with a steady rest device has been proposed (see, for example, Patent Document 1).

[0003] Furthermore, when installing a steady rest for long workpieces on a CNC lathe, it is sometimes necessary to completely replace the existing equipment. Furthermore, since the existing equipment must be capable of mounting a steady rest, if the existing equipment is not capable of doing so, it is necessary to separate the process, such as by reducing the workpiece's protrusion after machining the outer diameter, resulting in a decrease in productivity. Furthermore, many conventional steady rests require manual alignment, making automation difficult. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-058172 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a steady rest device that can be attached to a turret or tool spindle when machining a long workpiece on a CNC lathe or CNC combined lathe, and that can support the long workpiece with a constant supporting force. [Means for solving the problem]

[0006] In order to achieve the above object, the anti-vibration device of the present invention is characterized by comprising a device main body connected to a turret or a tool spindle, a hole provided in the device main body for inserting a long workpiece, a pair of fixed rollers arranged on the outer edge of the hole, a movable roller arranged on the outer edge of the hole in a position opposite the pair of fixed rollers, a slider that moves the movable roller toward and away from the workpiece, a power transmission mechanism that transmits power applied from the turret or the tool spindle to the slider, and a power restriction mechanism that restricts the power applied to the slider from the power transmission mechanism. [Effects of the Invention]

[0007] The steady rest device of the present invention includes a device body connected to a turret or tool spindle, a hole provided in the device body for inserting a long workpiece, a pair of fixed rollers positioned on the outer edge of the hole, a movable roller positioned on the outer edge of the hole opposite the pair of fixed rollers, a slider for moving the movable roller toward and away from the workpiece, a power transmission mechanism for transmitting power from the turret or tool spindle to the slider, and a power restriction mechanism for restricting the power applied to the slider from the power transmission mechanism. This device can be installed on an existing CNC lathe or CNC combined lathe, and can utilize the rotation of the turret's rotary tool shaft or the pressure of the internal coolant supply as power. The power restriction mechanism can support the tip of a long workpiece with a constant supporting force, allowing it to be machined into a desired shape. This eliminates the need to replace the entire existing equipment when installing the steady rest device. Furthermore, even if the existing equipment is not designed to accommodate the steady rest device, workpieces can be machined without dividing the process, preventing a decrease in productivity. Furthermore, by combining it with an automatic tool changer (ATC), it becomes possible to automatically install the steady rest device and attach cutting tools to the turret.

[0008] The anti-vibration device of the present invention can include a device main body connected to the turret, a hole provided in the device main body for inserting a long workpiece, a pair of fixed rollers arranged on the outer edge of the hole, a movable roller arranged at a position opposite the pair of fixed rollers on the outer edge of the hole, a slider that moves the movable roller back and forth toward the workpiece, an input shaft to which the rotational power of the turret's rotating tool shaft is input, a shaft connected to the slider, and a torque limiter connected between the input shaft and the shaft to regulate the rotational power transmitted to the shaft.

[0009] The apparatus may also include a device body connected to the turret, a hole provided in the device body for inserting a long workpiece, a pair of fixed rollers arranged on the outer edge of the hole, a movable roller arranged on the outer edge of the hole in a position facing the pair of fixed rollers, a slider for moving the movable roller back and forth toward the workpiece, an inlet for introducing internal oil supplied from the turret, a hydraulic path for transmitting the pressure of the internal oil supply to the slider, and an orifice plate for regulating the pressure transmitted to the slider. Furthermore, it is preferable to include a spring for urging the slider in the backward direction.

[0010] Alternatively, the tool may include a device body connected to the tool spindle, a hole provided in the device body for inserting a long workpiece, a pair of fixed rollers arranged on the outer edge of the hole, a movable roller arranged on the outer edge of the hole in a position facing the pair of fixed rollers, a slider for moving the movable roller toward and away from the workpiece, an inlet for introducing internal oil supplied from the tool spindle, a hydraulic path for transmitting the pressure of the internal oil supply to the slider, and an orifice plate for regulating the pressure transmitted to the slider. Furthermore, it is preferable to include a spring for urging the slider in the backward direction. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an explanatory diagram showing an example of a machine tool in which a steady rest device according to an embodiment of the present invention can be used; [Figure 2] 1 is a cross-sectional view showing an example of a steady rest device according to an embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view showing a modified example of the steady rest device according to the embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing another modified example of the steady rest device according to the embodiment of the present invention. [Figure 5] 3(a) to 3(d) are perspective views showing the procedure for machining a workpiece using the steady rest device of FIG. 2. [Figure 6]6(a) and 6(b) are explanatory views each showing an enlarged view of a main part of the steady rest device in the procedure of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings, in which: Figure 1 shows a machine tool that can use a steady rest device according to an embodiment of the present invention;

[0013] As shown in Fig. 1, machine tool 1 is equipped with a holding device 3, an upper tool rest 5, and a lower tool rest 7 on a machine base 2. Machine tool 1 also has an internal oil supply source and hydraulic paths for supplying internal oil (coolant) to a tool spindle S provided on the upper tool rest 5 and a turret 8 provided on the lower tool rest 7.

[0014] The holding device 3 is equipped with a chuck 4 that detachably holds a long workpiece W. The holding device 3 can rotate the workpiece W around the central axis of the main spindle L, which is parallel to the Z axis, using a built-in rotation drive device.

[0015] The upper tool post 5 can be moved in the X-, Y-, and Z-axis directions by various advancing / retracting mechanisms, lifting mechanisms, and drive devices mounted on the column 6. This configuration allows the position of the tool spindle S mounted on the upper tool post 5 to move three-dimensionally. The tool spindle S is also configured to be rotatable around a central axis parallel to the Y-axis. The tool spindle S can be rotated around a central axis parallel to the XZ plane by a built-in rotation drive device. The tool spindle S is also provided with a clamping mechanism for detachably holding a cutting tool T or a steady rest (described later). For example, when a cutting tool T is attached to the tool spindle S, the cutting tool T can be rotated to cut a workpiece W, and when a steady rest (device) is attached to the tool spindle S, the workpiece W can be held. The tool spindle S can also supply internal coolant to the attached cutting tool T or steady rest (device).

[0016] The lower tool rest 7 is equipped with a turret 8 that holds the cutting tool T and a steady rest device (described later), and a built-in rotation drive device allows the turret 8 to rotate around a central axis parallel to the Z axis. The turret 8 is polygonal in shape with multiple tool mounting surfaces, and multiple cutting tools T and steady rest devices can be attached radially. As the turret 8 rotates around its central axis, the cutting tool T and steady rest devices held on the tool mounting surfaces move circumferentially, and any cutting tool T or steady rest device used in cutting is positioned relative to the workpiece W. Furthermore, the turret 8 can provide rotational power to each of the attached cutting tools T and steady rest devices via a rotary drive shaft built into the turret 8, and can also supply internal oil.

[0017] The lower tool post 7 can be moved in the X-axis direction and the Z-axis direction by various advancing and retreating mechanisms, lifting mechanisms, driving devices, etc. With this configuration, the position of the turret 8 provided on the lower tool post 7 can be moved two-dimensionally.

[0018] As shown in FIG. 2 , the steady rest device 20 includes a device body 21 connected to the turret 8. The device body 21 can be fixed to the turret 8 with bolts. The device body 21 of the steady rest device 20 has a hole 22 at the tip end thereof for inserting a long workpiece W. A plurality of rotatable rollers are arranged on the outer edge of the hole 22, including a pair of fixed rollers 23 and a movable roller 24. The movable roller 24 is positioned opposite the pair of fixed rollers 23. The rotation of these rollers enables the workpiece W to be held and machined while being rotated. A slider 25 is provided inside the device body 21 and is connected to the movable roller 24. The slider 25 moves the movable roller 24 toward and away from the workpiece W. The slider 25 has an oval through-hole 25 a, and a cylindrical pin 25 b is inserted into the through-hole 25 a to regulate the stroke of the slider 25. The shaft 27 is rotatably supported by the device body 21 via a bearing 29a.

[0019] The steady rest device 20 further includes an input shaft 26 to which the rotational power of the rotary tool shaft of the turret 8 is input. The input shaft 26 is rotatably supported relative to the device body 21 via a bearing 29b. One end of a shaft 27 is connected to the input shaft 26, and the other end of the shaft 27 is connected to the slider 25. A torque limiter 28 is connected between the input shaft 26 and the shaft 27. The torque limiter 28 regulates the rotational power transmitted to the shaft 27. Specifically, the torque limiter 28 is configured to cause the shaft 27 to idle when the rotational power of the rotary tool shaft of the turret 8 exceeds a predetermined torque, thereby preventing the rotational power of the rotary tool shaft from being transmitted to the slider 25. When the input shaft 26 rotates in response to the rotational power of the rotary tool shaft of the turret 8, the shaft 27 rotates accordingly. For example, the slider 25, which has a ball screw, receives the rotation of the shaft 27 and advances toward the workpiece W, thereby pushing up the movable roller 24. In this way, the steady rest device 20 has a mechanism for converting the rotation of the rotary tool shaft into linear motion. In this type of steady rest device 20, the input shaft 26 and the shaft 27 form a power transmission mechanism that transmits the power (rotational power of the rotary tool shaft) applied from the turret 8 to the slider 25, and the torque limiter 28 forms a power restriction mechanism that restricts the power applied from the power transmission mechanism to the slider 25.

[0020] The steady rest device 20 is able to support the workpiece W by using the rotation of the rotary tool shaft of the turret 8 as power. Specifically, the rotational power of the rotary tool shaft is transmitted to the slider 25 via the input shaft 26 and the shaft 27, thereby pushing up the slider 25, and in response, the movable roller 24 comes into contact with the workpiece W and is able to support the workpiece W together with the fixed roller 23. Furthermore, when the rotational power of the rotary tool shaft of the turret 8 reaches a predetermined torque or more, the torque limiter 28 causes the shaft 27 to spin freely, thereby regulating the support force for the workpiece W to a constant value.

[0021] FIG. 3 shows a modified example of a steady rest device according to an embodiment of the present invention. As shown in FIG. 3, the steady rest device 30 includes a device body 31 connected to a turret 8. The device body 31 can be fixed to the turret 8 with bolts. The device body 31 of the steady rest device 30 has a hole 32 at the tip end thereof for inserting a long workpiece W. A plurality of rotatable rollers are arranged on the outer edge of the hole 32, including a pair of fixed rollers 33 and a movable roller 34. The movable roller 34 is positioned opposite the fixed roller 33. A slider 35 is provided inside the device body 31 and is connected to the movable roller 34. The slider 35 moves the movable roller 34 toward and away from the workpiece W. The slider 35 has an oval through-hole 35a, and a cylindrical pin 35b is inserted through the through-hole 35a to regulate the stroke of the slider 35. The slider 35 is also provided with a spring 39 configured to bias the slider 35 in the backward direction (direction away from the workpiece W).

[0022] The steady rest device 30 is further provided with an inlet 36 through which the internal coolant supplied from the turret 8 is introduced, a hydraulic path 37 that transmits the pressure of the internal coolant to the slider 35, and an orifice plate 38 that regulates the pressure transmitted to the slider 35 and discharges the internal coolant from the hydraulic path 37. In this type of steady rest device 30, the inlet 36 and the hydraulic path 37 form a power transmission mechanism that transmits power (internal coolant pressure) applied from the tool spindle S to the slider 35, and the orifice plate 38 forms a power regulation mechanism that regulates the power applied from the power transmission mechanism to the slider 35. The orifice plate 38 can also be configured to be detachable from the steady rest device 30. In this case, it is preferable to prepare multiple types of orifice plates 38 with different diameters of discharge holes for the internal coolant. This allows for a mechanism that allows the internal coolant pressure to be changed by replacing the orifice plate 38 to match the desired internal coolant pressure.

[0023] The steady rest 30 can support the workpiece W by using the pressure of the internal oil supply supplied from the turret 8 as power. Specifically, by taking in the internal oil supply through the inlet 36, the pressure pushes up the slider 35, causing the movable roller 34 to abut against the workpiece W and support the workpiece W together with the fixed roller 33. At this time, a small amount of internal oil is discharged from the orifice plate 38. This is because pressure relief is required to return the slider 35 to its initial position. Furthermore, by discharging the internal oil supply from the orifice plate 38, the pressure in the hydraulic path 37 is kept constant, and the support force for the workpiece W can be regulated to a constant level. On the other hand, when releasing the workpiece W, the supply of internal oil is stopped and the slider 35 can be returned to its initial position by the spring 39. However, if the return force of the spring 39 is weak, the turret 8 may move in the +X-axis direction, causing the workpiece W to forcibly push down the slider 35, thereby releasing the workpiece W.

[0024] FIG. 4 shows another modified example of a steady rest device according to an embodiment of the present invention. As shown in FIG. 4, the steady rest device 40 includes a device body 41 connected to a tool spindle S. The device body 41 has a tapered shank that is fitted onto the tool spindle S and fixed thereto. A hole 42 is provided at the tip of the device body 41 in the steady rest device 40, through which a long workpiece W is inserted. A plurality of rotatable rollers are arranged on the outer edge of the hole 42, including a pair of fixed rollers 43 and a movable roller 44. The movable roller 44 is positioned opposite the fixed roller 43. A slider 45 is provided inside the device body 41 and is connected to the movable roller 44. The slider 45 moves the movable roller 44 toward and away from the workpiece W. The slider 45 has an oval through-hole 45a, and a cylindrical pin 45b is inserted into the through-hole 45a to regulate the stroke of the slider 45. The slider 45 is also provided with a spring 49 configured to bias the slider 45 in the backward direction (direction away from the workpiece W).

[0025] The steady rest device 40 further includes an inlet 46 through which the internal coolant supplied from the tool spindle S is introduced, a hydraulic path 47 that transmits the pressure of the internal coolant to the slider 45, and an orifice plate 48 that regulates the pressure transmitted to the slider 45 and discharges the internal coolant from the hydraulic path 47. In this type of steady rest device 40, the inlet 46 and the hydraulic path 47 form a power transmission mechanism that transmits power (internal coolant pressure) applied from the tool spindle S to the slider 45, and the orifice plate 48 forms a power regulation mechanism that regulates the power applied from the power transmission mechanism to the slider 45. The orifice plate 48 can also be configured to be detachable from the steady rest device 40. In this case, it is preferable to prepare multiple types of orifice plates 48 with different diameters of discharge holes for the internal coolant. This allows for a mechanism that allows the internal coolant pressure to be changed by replacing the orifice plate 48 to match the desired internal coolant pressure.

[0026] The steady rest device 40 can support the workpiece W by using the pressure of the internal oil supply supplied from the tool spindle S as power. Specifically, by taking in the internal oil supply through the inlet 46, the pressure pushes down the slider 45, causing the movable roller 44 to abut against the workpiece W and support the workpiece W together with the fixed roller 43. At this time, a small amount of internal oil is discharged from the orifice plate 48. This is because pressure relief is required to return the slider 45 to its initial position. Furthermore, by discharging the internal oil supply through the orifice plate 48, the pressure in the hydraulic path 47 is kept constant, thereby regulating the support force for the workpiece W to a constant level. On the other hand, when releasing the workpiece W, the supply of internal oil is stopped and the slider 45 can be returned to its initial position by the spring 49. However, if the return force of the spring 49 is weak, the tool spindle S may be moved in the -X-axis direction to forcibly push up the slider 45 with the workpiece W, thereby releasing the workpiece W.

[0027] 5(a) to 5(d) show the procedure for machining a workpiece using the steady rest device of FIG. 2. First, as shown in FIG. 5(a), the steady rest device 20 is attached to the turret 8, and the turret 8 is moved in the +X-axis direction (upward in the figure). At this time, the turret 8 is moved so that the steady rest device 20 is located at a predetermined height position (predetermined position in the X-axis direction). More specifically, the steady rest device 20 is positioned in the X-axis direction so that it is higher by a predetermined amount (for example, 2 to 3 mm) than the height position at which the fixed roller 23 abuts against the workpiece W, so that the workpiece W does not interfere with both the fixed roller 23 and the movable roller 24 when the workpiece W is inserted into the hole 22.

[0028] Thereafter, as shown in FIG. 5(b), the turret 8 is moved in the -Z-axis direction (leftward in the drawing). At this time, the workpiece W is inserted into the hole 22, and the steady rest 20 is positioned relative to the workpiece W so that the tip of the workpiece W protrudes a predetermined amount from the hole 22. After the steady rest 20 is positioned in this manner, as shown in FIG. 5(c), the turret 8 is moved in the -X-axis direction (downward in the drawing), but the turret 8 is moved so that the top of the workpiece W and the pair of fixed rollers 23 are in close contact with each other. FIG. 6(a) shows the state in which the workpiece W and the pair of fixed rollers 23 are in close contact with each other. Note that coordinates are set in advance so that the position where the workpiece W abuts against the fixed rollers 23 and the center of the spindle L are aligned.

[0029] With the workpiece W and the pair of fixed rollers 23 in close contact with each other in this manner, the movable roller 24 moves in the +X-axis direction. At this time, the rotational power of the rotary tool shaft of the turret 8 is transmitted to the slider 25 via the input shaft 26 and the shaft 27, and as the slider 25 moves in the +X-axis direction, the movable roller 24 is pushed up and moves in the +X-axis direction, and the movable roller 24 comes into contact with the workpiece W. FIG. 6(b) shows the state in which the workpiece W and the movable roller 24 are in close contact with each other. In this way, the workpiece W is properly held by the steady rest device 20. Thereafter, as shown in FIG. 5(d), the tool spindle S is moved in the -Z-axis direction (to the left in the figure), and machining of the workpiece W begins with the cutting tool T attached to the tool spindle S.

[0030] While the case where the steady rest device 20 shown in Fig. 2 is used has been described, the steady rest device 30 shown in Fig. 3 is attached to the turret 8 in the same way as the steady rest device 20 shown in Fig. 2, and so when the steady rest device 30 is used, the process is the same up to the machining of the workpiece W. Furthermore, when the steady rest device 40 shown in Fig. 4 is used, although detailed procedures will be omitted, by attaching the steady rest device 40 to the tool spindle S and interlocking the tool spindle S and the turret 8, the workpiece W can be held appropriately using the steady rest device 40.

[0031] The steady rest devices 20, 30, 40 described above include device bodies 21, 31, 41 connected to the turret 8 or the tool spindle S, hole portions 22, 32, 42 provided in the device bodies 21, 31, 41 for inserting a long workpiece W, a pair of fixed rollers 23, 33, 43 arranged on the outer edges of the hole portions 22, 32, 42, movable rollers 24, 34, 44 arranged at positions facing the pair of fixed rollers 23, 33, 43 on the outer edges of the hole portions 22, 32, 42, sliders 25, 35, 45 for moving the movable rollers 24, 34, 44 toward and away from the workpiece W, and the turret 8 or the tool spindle S. The device is equipped with a power transmission mechanism that transmits power applied from the turret 8 or tool spindle S to the sliders 25, 35, 45, a power transmission mechanism that transmits power applied from the turret 8 or tool spindle S to the sliders 25, 35, 45, and a power restriction mechanism that restricts the power applied from the power transmission mechanism to the sliders 25, 35, 45. By attaching the device to an existing CNC lathe or CNC combined lathe and using the rotation of the rotary tool shaft of the turret 8 installed in the existing equipment or the ejection pressure of the internal oil supply (coolant) as power, the tip of a long workpiece W can be machined into a desired shape while the power restriction mechanism supports it with a constant supporting force. This eliminates the need to replace the entire existing equipment when introducing a steady rest, and even if the existing equipment is not designed to be able to install a steady rest, the workpiece can be machined without dividing the process, so there is no decrease in productivity. Furthermore, by combining an automatic tool changer (ATC), it becomes possible to automatically mount the steady rest devices 20, 30, 40 and attach the cutting tool T to the turret 8.

[0032] In addition, anti-sway devices that grip long workpieces W using hydraulic or electric jaws have also been proposed, but these devices often have complex structures, and their introduction requires significant changes to existing equipment in terms of both hardware and software. In contrast, the anti-sway devices 20, 30, and 40 of the present invention have a single drive point (slider 25, 35, and 45), which eliminates the need for a complex structure and allows for relatively inexpensive manufacture. Furthermore, the presence of holes 22, 32, and 42 eliminates the need for openings in the areas that hold the workpieces W, thereby increasing the rigidity of the anti-sway devices 20, 30, and 40 and contributing to improved durability. [Explanation of symbols]

[0033] 1 Machine tools 2 machines 3 Holding device 4. Chuck 5 Upper tool post 6. Column 7 Lower tool rest 8 Turrets 20, 30, 40 Steady rest device 21, 31, 41 Device body 22,32,42 Hole 23, 33, 43 Fixed rollers 24, 34, 44 Movable rollers 25, 35, 45 slider 26 Input shaft 27 Shaft 28 Torque limiter 36,46 intake port 37,47 Hydraulic path 38,48 Orifice plate L spindle S Tool spindle T-cutting tool double work

Claims

1. a pair of fixed rollers arranged on the outer edge of the hole; a movable roller arranged on the outer edge of the hole in a position facing the pair of fixed rollers; a slider that moves the movable roller toward and away from the workpiece; a power transmission mechanism that transmits power applied from the turret or the tool spindle to the slider; and a power restriction mechanism that restricts the power applied from the power transmission mechanism to the slider.

2. a slider that moves the movable roller toward and away from the workpiece; an input shaft to which rotational power of a rotary tool shaft of the turret is input; a shaft connected to the slider; and a torque limiter that is connected between the input shaft and the shaft and that limits the rotational power transmitted to the shaft.

3. a pair of fixed rollers arranged on the outer edge of the hole; a movable roller arranged on the outer edge of the hole in a position opposite the pair of fixed rollers; a slider that moves the movable roller toward and away from the work; an inlet through which internal oil supplied from the turret is introduced; a hydraulic path that transmits the pressure of the internal oil supply to the slider; and an orifice plate that regulates the pressure transmitted to the slider.

4. a pair of fixed rollers arranged on the outer edge of the hole; a movable roller arranged on the outer edge of the hole in a position facing the pair of fixed rollers; a slider that moves the movable roller toward and away from the workpiece; an inlet through which internal oil supply supplied from the tool spindle is introduced; a hydraulic path that transmits the pressure of the internal oil supply to the slider; and an orifice plate that regulates the pressure transmitted to the slider.

5. 5. The steady rest device according to claim 3, further comprising a spring for biasing the slider in a backward direction.

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