Working machinery

Abstract

A machine tool capable of more simply configuring a feed mechanism for applying a driving force to a moving body is provided. [Solution] The machine tool comprises a first movable body (310) supported by a bed (21) so as to be slidable in a predetermined direction, a second movable body (320) supported by the bed (21) so as to be slidable in a predetermined direction, a rack (52) extending in the predetermined direction, a first feed mechanism (51) having a first pinion (54) provided on the first movable body (310) and rotating while engaging with the rack (52), and applying a driving force to the first movable body (310), a rack (52) shared with the first feed mechanism (51), and a second pinion (63) provided on the second movable body (320) and rotating while engaging with the rack (52), and applying a driving force to the second movable body (320).

Description

[Technical Field]

[0001] The present invention relates to a machine tool. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2010-264563 (Patent Document 1) discloses a lathe equipped with a first spindle capable of holding one end of a workpiece, a second spindle holding the other end of the workpiece and movable in the Z-axis direction which is the axial direction of the first spindle, a tool rest holding a tool and movable in the Z-axis direction, and a plurality of steady rests movable between the first and second spindles in the Z-axis direction and the X-axis direction which is perpendicular to the Z-axis direction, for supporting the middle portion of the workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-264563 Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in the above-mentioned Patent Document 1, the bed of the machine tool is equipped with movable bodies that can move in the Z-axis direction, such as a work spindle, a tool rest, and a steady rest. In machine tools, there is a demand for a simpler configuration of the feed mechanism for applying driving force to these movable bodies.

[0005] An object of the present invention is to provide a machine tool that can more simply configure a feed mechanism for applying a driving force to a moving body. [Means for solving the problem]

[0006] A machine tool according to the present invention comprises a first movable body supported by a bed so as to be slidable in a predetermined direction, a second movable body supported by the bed so as to be slidable in a predetermined direction, a first feed mechanism having a rack extending in the predetermined direction and a first pinion provided on the first movable body and rotating while engaging with the rack, and applying a driving force in the predetermined direction to the first movable body, and a second feed mechanism having a rack shared with the first feed mechanism and a second pinion provided on the second movable body and rotating while engaging with the rack, and applying a driving force in the predetermined direction to the second movable body. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a machine tool that can more simply configure a feed mechanism for applying a driving force to a moving body. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a machine tool according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view showing the machine tool in FIG. [Figure 3] FIG. 3 is a side view showing the machine tool as seen in the direction indicated by arrow III in FIG. 2. [Figure 4] FIG. 2 is a perspective view showing a bed provided in the machine tool in FIG. [Figure 5] FIG. 5 is a perspective view showing the bed as viewed in the direction indicated by arrow V in FIG. 4. [Figure 6] 4 is a side view showing the machine tool in the area surrounded by the two-dot chain line VI in FIG. 3. [Figure 7] 7 is a side view showing the bed in the area surrounded by the two-dot chain line VII in FIG. 5. FIG. [Figure 8] 2 is an exploded assembly diagram for explaining the configuration of a first feed mechanism and a linear scale provided in the machine tool in FIG. 1. FIG. [Figure 9] 9 is a cross-sectional view showing the machine tool as seen in the direction of the arrows on line IX-IX in FIG. 2. [Figure 10]3 is a cross-sectional view showing the machine tool as seen in the direction of the arrow on line XX in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0010] Fig. 1 is a perspective view showing a machine tool according to an embodiment of the present invention. Fig. 2 is a front view showing the machine tool in Fig. 1. Fig. 3 is a side view showing the machine tool as seen in the direction indicated by arrow III in Fig. 2. In Figs. 1 to 3, the internal structure of the machine tool is shown by seeing through a cover body (splash guard) that forms the exterior of the machine tool.

[0011] Fig. 4 is a perspective view showing a bed provided in the machine tool in Fig. 1. Fig. 5 is a perspective view showing the bed as viewed in the direction indicated by arrow V in Fig. 4.

[0012] 1 to 5, machine tool 100 in this embodiment is a lathe that machines a workpiece by bringing a tool into contact with the rotating workpiece. Machine tool 100 is an NC (Numerically Controlled) machine tool in which various operations for machining a workpiece are automated by numerical control using a computer.

[0013] The machine tool 100 has a bed 21, a first workpiece spindle 12, a second workpiece spindle 14, a tool rest 16, and a plurality of steady rests 31 (31A, 31B).

[0014] The first work spindle 12, the second work spindle 14, the tool rest 16, and the plurality of steady rest devices 31 are mounted on a bed 21. The bed 21 is a base member for supporting the first work spindle 12, the second work spindle 14, the tool rest 16, and the plurality of steady rest devices 31, and is installed on the floor of a factory or the like. The bed 21 is made of metal such as cast iron.

[0015] The bed 21 is a slant bed type, and the support surfaces that support the first workpiece spindle 12, the second workpiece spindle 14, the tool rest 16, and the plurality of steady rests 31 are inclined.

[0016] The first workpiece spindle 12, the second workpiece spindle 14, the tool rest 16, and the plurality of steady rest devices 31 are arranged in the machining area 200. The machining area 200 is a space where the workpiece is machined, and is sealed by a cover (not shown) to prevent foreign matter such as chips or cutting oil generated during the machining of the workpiece from leaking outside the machining area 200.

[0017] The first work spindle 12 is capable of holding a workpiece. The first work spindle 12 rotates the workpiece around a central rotation axis 110 that is parallel to the Z-axis that extends horizontally. The second work spindle 14 is capable of holding a workpiece. The second work spindle 14 is disposed opposite the first work spindle 12 in the axial direction of the Z-axis (hereinafter also referred to as the "Z-axis direction"). The second work spindle 14 rotates the workpiece around the central rotation axis 110.

[0018] The first workpiece spindle 12 is fixed to a bed 21. The second workpiece spindle 14 is attached to the bed 21. The second workpiece spindle can be moved in the Z-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc.

[0019] The tool rest 16 can hold multiple tools. The tool rest 16 is a turret-type tool rest that moves the multiple tools it holds in the circumferential direction of a rotation center axis that is parallel to the Z axis, thereby indexing the tool to be used for machining.

[0020] The tool post 16 has a saddle (not shown) and a cross slide (not shown). The saddle is attached to the bed 21. The saddle can be moved in the Z-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc. The cross slide is attached to the saddle. The cross slide can be moved in the X-axis direction (hereinafter also referred to as the "X-axis direction"), which is perpendicular to the Z-axis and inclined relative to the vertical and horizontal directions, by various feed mechanisms, guide mechanisms, servo motors, etc.

[0021] In this configuration, the tool post 16 is movable in the X-axis direction and the Z-axis direction. The tool post 16 may be configured to be movable in the Y-axis direction (hereinafter also referred to as the "Y-axis direction"), which is perpendicular to the X-axis and Z-axis, in addition to the X-axis direction and the Z-axis direction.

[0022] The steady rest 31 is a device for preventing the vibration of a workpiece. The steady rest 31 is a device for preventing the vibration of a workpiece held by the first workpiece spindle 12 and / or the second workpiece spindle 14. The steady rest 31 is also called a steady rest or a workpiece support.

[0023] The plurality of steady rest devices 31 are provided opposite each other in the Z-axis direction. The plurality of steady rest devices 31 are provided between the first work spindle 12 and the second work spindle 14 in the Z-axis direction. The steady rest device 31A is provided between the steady rest device 31B and the second work spindle 14 in the Z-axis direction. The steady rest device 31B is provided between the first work spindle 12 and the steady rest device 31A in the Z-axis direction.

[0024] The steady rest device 31 can be moved in the Z-axis direction by various feed mechanisms, guide mechanisms, servo motors, etc. Note that the machine tool 100 may have one steady rest device 31, or may have three or more steady rest devices 31.

[0025] The second workpiece spindle 14, the plurality of steady rests 31, and the tool rest 16 are supported by a bed 21 so as to be slidable in the Z-axis direction.

[0026] More specifically, the bed 21 has pedestals 23 (23J, 23K). The pedestal 23 extends in the Z-axis direction. The pedestal 23 has a thickness in the Y-axis direction and a constant width in the X-axis direction, while extending in the Z-axis direction.

[0027] Pedestal 23 is made of the same casting that constitutes bed 21. Pedestal 23 is provided on the support surface of bed 21 that supports second workpiece spindle 14 and a plurality of steady rest devices 31. Pedestal 23J and pedestal 23K are provided at an interval from each other in a direction (X-axis direction) perpendicular to the Z-axis direction. Pedestal 23J is provided at a position spaced apart diagonally upward from pedestal 23K along the X-axis direction.

[0028] The second work spindle 14 and the plurality of steady rest devices 31 are disposed on a pedestal 23. The pedestal 23 bears the weight of the second work spindle 14 and the plurality of steady rest devices 31. The pedestal 23 constitutes a sliding guide mechanism that supports the second work spindle 14 and the plurality of steady rest devices 31 so that they can slide in the Z-axis direction.

[0029] The bed 21 further includes pedestals 22 (22J, 22K). The pedestal 22 extends in the Z-axis direction. The pedestal 22 has a thickness in the Y-axis direction and a constant width in the X-axis direction, while extending in the Z-axis direction.

[0030] Pedestal 22 is made of the same casting that makes up bed 21. Pedestal 22 is provided on the support surface of bed 21 that supports tool rest 16. Pedestal 22J and pedestal 22K are provided at an interval from each other in a direction perpendicular to the Z-axis direction (X-axis direction). Pedestal 22J is provided at a position spaced apart from pedestal 22K in the diagonally upward direction along the X-axis direction. Pedestal 22K is provided at a position spaced apart from pedestal 23J in the diagonally upward direction along the X-axis direction.

[0031] The tool rest 16 (saddle) is disposed on a pedestal 22. The pedestal 22 supports the weight of the tool rest 16. The pedestal 22 constitutes a sliding guide mechanism that supports the tool rest 16 (saddle) so that it can slide in the Z-axis direction.

[0032] The feed mechanism that applies a driving force in the Z-axis direction to the tool post 16 (saddle) is composed of a ball screw. Telescopic covers (not shown) that can deform in accordance with the movement of the tool post 16 in the Z-axis direction are provided on both sides of the tool post 16 (saddle) in the Z-axis direction. The ball screw and base 22 that constitute the feed mechanism are covered by the telescopic covers. The ball screw and base 22 that constitute the feed mechanism are separated from the machining area 200 by the telescopic covers.

[0033] Next, a feed mechanism that applies a driving force in the Z-axis direction to the second workpiece spindle 14 and the plurality of steady rest devices 31 will be described.

[0034] Fig. 6 is a side view showing the machine tool in the area surrounded by the two-dot chain line VI in Fig. 3. Fig. 7 is a side view showing the bed in the area surrounded by the two-dot chain line VII in Fig. 5. Fig. 8 is an exploded assembly view for explaining the configuration of a first feed mechanism and a linear scale provided in the machine tool in Fig. 1. Fig. 9 is a cross-sectional view showing the machine tool as seen in the direction of the arrows on line IX-IX in Fig. 2. Fig. 10 is a cross-sectional view showing the machine tool as seen in the direction of the arrows on line XX in Fig. 2.

[0035] 1 to 10, machine tool 100 further includes a first feed mechanism 51 and a servo motor 53. First feed mechanism 51 applies a driving force in the Z-axis direction to second workpiece spindle 14. Servo motor 53 is provided as a power source for first feed mechanism 51.

[0036] The first feed mechanism 51 has a rack 52 and a first pinion 54. The rack 52 extends in the Z-axis direction (see FIG. 2). The rack 52 is attached to the bed 21. The rack 52 is attached to the bed 21 via a bracket 71, which will be described later. The first pinion 54 is provided on the second work spindle 14. The first pinion 54 rotates while engaging with the rack 52. The first pinion 54 receives rotational motion output by the servo motor 53 and rotates while engaging with the rack 52.

[0037] Machine tool 100 further has a bracket 71. Bracket 71 extends in the Z-axis direction (see FIGS. 2 and 4). Bracket 71 is made of a plate material that extends in the Z-axis direction while having a thickness in the Y-axis direction. Bracket 71 is an elongated body whose longitudinal direction corresponds to the Z-axis direction. The length of bracket 71 in the Z-axis direction is longer than the length (width) of bracket 71 in the X-axis direction and is longer than the length (thickness) of bracket 71 in the Y-axis direction.

[0038] The bracket 71 is attached to the bed 21. The bracket 71 is fastened to the bed 21 using bolts or the like. The bracket 71 is attached to the base 23. The bracket 71 is attached to the base 23K.

[0039] 7, the base 23K has a guide surface 23a. The guide surface 23a is a flat surface that extends in the Z-axis direction and is inclined relative to the horizontal. The guide surface 23a guides the second workpiece spindle 14 and the plurality of steady rest devices 31 in the Z-axis direction.

[0040] The guide surface 23a has a constant width in the X-axis direction and extends in a strip shape in the Z-axis direction. The guide surface 23a is formed of a plane (X-axis-Z-axis plane) perpendicular to the Y-axis. The guide surface 23a is in sliding contact with the second work spindle 14 and the plurality of steady rest devices 31. Lubricant is supplied to the sliding surfaces between the guide surface 23a and the second work spindle 14 and the plurality of steady rest devices 31. The second work spindle 14 and the plurality of steady rest devices 31 move in the Z-axis direction while making surface contact with the guide surface 23a.

[0041] The bracket 71 has a top surface 71a. The top surface 71a has a constant width in the X-axis direction and extends in a strip shape in the Z-axis direction. The top surface 71a is formed on a plane (X-axis-Z-axis plane) perpendicular to the Y-axis. The top surface 71a is disposed so as to be flush with the guide surface 23a. There is no step between the top surface 71a and the guide surface 23a. The top surface 71a is disposed below the guide surface 23a. The top surface 71a extends in the Z-axis direction along the lower edge of the guide surface 23a.

[0042] The bracket 71 further has a first bottom surface 71b and a second bottom surface 71c. The first bottom surface 71b and the second bottom surface 71c are located on the back side of the top surface 71a in the Y-axis direction. The first bottom surface 71b is a plane perpendicular to the Y-axis (X-axis-Z plane). The second bottom surface 71c is a plane perpendicular to the Y-axis (X-axis-Z plane). The first bottom surface 71b and the second bottom surface 71c form a step in the Y-axis direction. The length (thickness) of the bracket 71 between the top surface 71a and the first bottom surface 71b in the Y-axis direction is shorter than the length (thickness) of the bracket 71 between the top surface 71a and the second bottom surface 71c in the Y-axis direction. The second bottom surface 71c is located between the first bottom surface 71b and the pedestal 23K in the X-axis direction.

[0043] The rack 52 is attached to the first bottom surface 71b. The toothed surface 52a of the rack 52 extends in the Z-axis direction within a plane (X-axis-Z-axis plane) perpendicular to the Y-axis. The length (thickness) of the rack 52 in the Y-axis direction is longer than the length (step) of the bracket 71 between the first bottom surface 71b and the second bottom surface 71c in the Y-axis direction. The toothed surface 52a of the rack 52 is provided at a position that protrudes beyond the second bottom surface 71c.

[0044] In a preferred mounting configuration of the rack 52 relative to the bed 21, the toothed surface 52a of the rack 52 faces diagonally downward. The toothed surface 52a of the rack 52 faces diagonally downward along the Y-axis direction. The toothed surface 52a of the rack 52 is provided on a side surface of the block that constitutes the rack 52 that faces diagonally downward. In a more preferred mounting configuration of the rack 52 relative to the bed 21, the toothed surface 52a of the rack 52 is positioned below the top surface 71a. The toothed surface 52a of the rack 52 is positioned at a position that is projected onto the top surface 71a in the vertical direction. When the toothed surface 52a of the rack 52 is projected onto the top surface 71a of the bracket 71 in the vertical direction, the entire toothed surface 52a is included in the top surface 71a.

[0045] The bracket 71 may be made up of a plurality of bracket segments arranged in the Z-axis direction. The rack 52 may be made up of a plurality of rack segments arranged in the Z-axis direction. The tooth surface 52a of the rack 52 may be integrally formed with the bracket 71.

[0046] As shown in FIGS. 3 and 6 , the servo motor 53 and the first pinion 54 are attached to the second workpiece spindle 14. The servo motor 53 can selectively output rotation in a forward direction or a reverse direction about a rotation center axis 120 via its output shaft. The rotation center axis 120 extends in the Y-axis direction. A reducer 56 is provided on the power transmission path from the servo motor 53 to the first pinion 54. The reducer 56 reduces the speed of the rotation from the servo motor 53, converts the rotation about the rotation center axis 120 by 90° into rotation about a rotation center axis 130, and transmits the rotation to the first pinion 54. The first pinion 54 can rotate about the rotation center axis 130. The rotation center axis 130 extends in the X-axis direction. The first pinion 54 meshes with the tooth surface 52 a of the rack 52.

[0047] The first pinion 54 is disposed below the top surface 71a and at a position projected in the vertical direction onto the top surface 71a of the bracket 71. As shown in Fig. 3, the second work spindle 14 is disposed between the rotation center shaft 110 and the first pinion 54 in the vertical direction.

[0048] As shown in FIGS. 1, 2, and 8, the first feed mechanism 51 has a pair of first pinions 54 (54p, 54q). The first pinions 54p and 54q are spaced apart from each other in the Z-axis direction. Each of the first pinions 54p and 54q is engaged with the rack 52. Each of the first pinions 54p and 54q is in mesh with the tooth surface 52a of the rack 52.

[0049] The first pinion 54p and the first pinion 54q are provided so as to apply a force (tension) in a direction moving them away from each other in the Z-axis direction or a force (compression) in a direction moving them toward each other in the Z-axis direction to the rack 52. When applying forces from the first pinion 54p and the first pinion 54q to the rack 52 in a direction moving them away from each other in the Z-axis direction, for example, the mounting positions of the first pinion 54p and the first pinion 54q on the second work spindle 14 may be shifted in a direction moving them away from each other in the Z-axis direction while the first pinion 54p and the first pinion 54q are each engaged with the tooth surface 52a of the rack 52. When applying a force from the first pinion 54p and the first pinion 54q to the rack 52 in a direction that moves them closer to each other in the Z-axis direction, for example, with each of the first pinion 54p and the first pinion 54q meshing with the tooth surface 52a of the rack 52, the mounting positions of the first pinion 54p and the first pinion 54q on the second work spindle 14 can be shifted in a direction that moves them closer to each other in the Z-axis direction.

[0050] Machine tool 100 has the above-described servo motor 53 and reducer 56 corresponding to first pinion 54p and first pinion 54q, respectively. A control device of machine tool 100 synchronously controls servo motor 53 provided corresponding to first pinion 54p and servo motor 53 provided corresponding to first pinion 54q.

[0051] 6 to 8, the machine tool 100 further includes a linear scale 85. The linear scale 85 constitutes a position detection mechanism that detects the respective positions of the second workpiece spindle 14 and the steady rest device 31 in the Z-axis direction.

[0052] 7 and 8, the linear scale 85 has a scale section 86. The scale section 86 extends in the Z-axis direction. The scale section 86 is attached to a bracket 71. The scale section 86 is attached to the bed 21 via the bracket 71. The scale section 86 is provided with a scale (not shown). More specifically, the scale section 86 has a base attached to the bracket 71, a scale body made of a magnetic material that is supported by the base and has a scale recorded magnetically, and a cover made of stainless steel foil or the like that is attached to the base so as to cover the scale body.

[0053] The scale portion 86 is attached to the second bottom surface 71c of the bracket 71. The scale portion 86 is disposed adjacent to the rack 52 in the X-axis direction. The scale portion 86 is disposed adjacent to the tooth surface 52a of the rack 52 in the X-axis direction.

[0054] As shown in FIG. 6, the linear scale 85 further has a head unit 87. The head unit 87 is attached to the second workpiece spindle 14. The head unit 87 faces the scale unit 86 with a gap in the Y-axis direction. The head unit 87 moves integrally with the second workpiece spindle 14 in the X-axis direction. The head unit 87 is capable of reading the scale marks provided on the scale unit 86. The head unit 87 is provided with a TMR (tunneling magnetoresistance) sensor for reading the scale marks recorded on the scale unit 86.

[0055] The head portion 87 is disposed below the top surface 71a and at a position projected onto the top surface 71a of the bracket 71 in the vertical direction. The second workpiece spindle 14 is disposed between the rotation center axis 110 and the head portion 87 in the vertical direction. The head portion 87 may be disposed between the first pinion 54p and the first pinion 54q in the Z-axis direction.

[0056] 6, the machine tool 100 has a control device 400. The control device 400 controls the operation of the machine tool 100.

[0057] The components of the control device 400 are realized by hardware including computing units such as a CPU (Central Processing Unit) and various computer processors, storage devices such as memory or storage, and wired or wireless communication lines connecting them, as well as software stored in the storage devices and supplying processing instructions to the computing units. The computer programs may be configured by device drivers, an operating system, various application programs located at higher layers thereof, or libraries that provide common functions to these programs.

[0058] The control device 400 has a numerical control device 410 and a servo driver 420. The numerical control device 410 executes a pre-designed machining program. The machining program is written, for example, as an NC (Numerical Control) program. The numerical control device 410 controls the servo driver 420 and other components in accordance with the machining program. The servo driver 420 controls the power supply to the servo motor 53 so that the servo motor 53 rotates in accordance with commands from the numerical control device 410, including a target position for the second workpiece spindle 14.

[0059] The linear scale 85 detects the position of the second work spindle 14 in the Z-axis direction, and outputs the detected position information of the second work spindle 14 to the servo driver 420. The servo driver 420 controls the power supply to the servo motor 53 so as to correct the difference between the position of the second work spindle 14 detected by the linear scale 85 and the position of the second work spindle 14 commanded by the numerical control device 410.

[0060] 6 and 8, the second work spindle 14 further includes a brake mechanism 91. The brake mechanism 91 is a device for fixing the position of the second work spindle 14 in the Z-axis direction.

[0061] The brake mechanism 91 is provided at the bottom of the second work spindle 14. The brake mechanism 91 has a brake pad 92 and an actuator (not shown). The brake pad 92 is made of a plate material whose thickness direction corresponds to the Y-axis direction. The brake pad 92 is arranged so as to face the pedestal 22 from the back side of the guide surface 23a in the Y-axis direction and to straddle the pedestals 22J and 22K in the X-axis direction. The actuator (not shown) is a device for stroking the brake pad 92 in the Y-axis direction, and may be an electromagnetic brake or a piston cylinder that uses fluid pressure such as hydraulic pressure.

[0062] An actuator (not shown) strokes the brake pad 92 obliquely upward along the Y-axis direction, causing the brake pad 92 to come into close contact with the pedestal 22. The position of the second work spindle 14 in the Z-axis direction is fixed by the frictional force generated between the brake pad 92 and the pedestal 22. An actuator 93 strokes the brake pad 92 obliquely downward along the Y-axis direction, causing the brake pad 92 to move away from the pedestal 22. The frictional force between the brake pad 92 and the pedestal 22 is eliminated, and the second work spindle 14 is released from fixation by the brake mechanism 91.

[0063] 1, 2, 9, and 10, the steady rest device 31 has a pair of arms 32, a plurality of rollers 33, and an actuator (not shown). Each arm 32 is supported rotatably about a rotation center axis extending in the Z-axis direction. The plurality of rollers 33 are provided at the tip of each arm 32 and at the base of the pair of arms 32, etc. The actuator (not shown) is a device for rotating the pair of arms 32, and may be a motor or a piston cylinder that uses fluid pressure such as hydraulic pressure. When the actuator (not shown) rotates the pair of arms 32 in accordance with the diameter of the workpiece to be supported, the outer circumferential surface of the workpiece is supported by the plurality of rollers 33.

[0064] Machine tool 100 further includes a second feed mechanism 61 and a servo motor 62. Second feed mechanism 61 applies a driving force in the Z-axis direction to steady rest device 31. Servo motor 62 is provided as a power source for second feed mechanism 61.

[0065] The second feed mechanism 61 has a rack 52 and a second pinion 63. The rack 52 is shared by the first feed mechanism 51 and the second feed mechanism 61. The first feed mechanism 51 and the second feed mechanism 61 share the rack 52. The second pinion 63 is provided in the steady rest device 31. The second pinion 63 rotates while engaged with the rack 52. The second pinion 63 receives the rotational motion output by the servo motor 62 and rotates while engaged with the rack 52.

[0066] As shown in FIGS. 9 and 10 , the servo motor 62 and the second pinion 63 are attached to the steady rest device 31. The servo motor 62 can selectively output rotation in a forward direction or a reverse direction about a rotation center axis 140 through its output shaft. The rotation center axis 140 extends in the Y-axis direction. A reducer 66 is provided on the power transmission path from the servo motor 62 to the second pinion 63. The reducer 66 reduces the speed of the rotation from the servo motor 62, converts the rotation about the rotation center axis 140 by 90° into rotation about a rotation center axis 150, and transmits the rotation to the second pinion 63. The second pinion 63 can rotate about the rotation center axis 150. The rotation center axis 150 extends in the X-axis direction. The second pinion 63 meshes with the tooth surface 52 a of the rack 52.

[0067] The second pinion 63 is disposed below the top surface 71a and at a position projected in the vertical direction onto the top surface 71a of the bracket 71. A vibration prevention device 31 is disposed between the rotation center shaft 110 and the second pinion 63 in the vertical direction.

[0068] The first pinion 54 and the second pinion 63 are arranged to overlap each other when viewed in the Z-axis direction. The servo motor 53 and the servo motor 62 are arranged to overlap each other when viewed in the Z-axis direction. The reducer 56 and the reducer 66 are arranged to overlap each other when viewed in the Z-axis direction.

[0069] The above-mentioned linear scale 85 and brake mechanism 91 are also provided in the steady rest device 31. The linear scale 85 and brake mechanism 91 are provided in the same form as in the second workpiece spindle 14. The steady rest device 31A and the steady rest device 31B have the same structure.

[0070] 1, 2, 4 and 9, no telescopic cover is provided on the support surface of the bed 21 on which the first work spindle 12, the steady rest 31B, the steady rest 31A and the second work spindle 14 are aligned in the Z-axis direction. The base 23 (23J, 23K) is exposed to the machining area 200 between the first work spindle 12 and the steady rest 31B in the Z-axis direction, between the steady rest 31B and the steady rest 31A in the Z-axis direction, and between the steady rest 31A and the second work spindle 14 in the Z-axis direction.

[0071] The bed 21 has a plurality of ribs 24. The ribs 24 have a rib shape that protrudes in the Y-axis direction and extends in the X-axis direction. The plurality of ribs 24 are provided at intervals from one another in the Z-axis direction. The pedestal 23J and the pedestal 23K are arranged at intervals from one another in the X-axis direction. Each of the pedestal 23J and the pedestal 23K extends in the Z-axis direction, straddling the tops of the plurality of ribs 24.

[0072] A passage 25 is provided between adjacent ribs 24 in the Z-axis direction. Passage 25 opens obliquely upward along the Y-axis direction between pedestal 23J and pedestal 23K. Passage 25 opens obliquely downward along the X-axis direction between the lower ends of adjacent ribs 24 in the Z-axis direction.

[0073] Machine tool 100 further includes a chip conveyor 81. Chip conveyor 81 is provided on the floor of a factory or the like, in front of bed 21. Chip conveyor 81 is provided directly below bracket 71.

[0074] Chips generated in the machining area 200 during workpiece machining are mainly collected by the chip conveyor 81 through the passage 25. Some of the chips adhere to the guide surface 23a of the base 23K. The chips move down the guide surface 23a and the top surface 71a of the bracket 71, drop from the bracket 71, and are collected by the chip conveyor 81.

[0075] To summarize the configuration of machine tool 100 in the embodiment of the present invention described above, machine tool 100 in the present embodiment comprises a first movable body 310 supported by bed 21 so as to be slidable in the Z-axis direction as a predetermined direction, a second movable body 320 supported by bed 21 so as to be slidable in the Z-axis direction, a rack 52 extending in the Z-axis direction, a first feed mechanism 51 having a first pinion 54 provided on first movable body 310 and rotating while engaging with rack 52, and applying a driving force in the Z-axis direction to first movable body 310, and a second feed mechanism 61 having a rack 52 shared with first feed mechanism 51 and a second pinion 63 provided on second movable body 320 and rotating while engaging with rack 52, and applying a driving force in the Z-axis direction to second movable body 320.

[0076] With this configuration, the rack 52 is shared between the first feed mechanism 51 that applies a driving force to the first moving body 310 (second workpiece spindle 14) and the second feed mechanism 61 that applies a driving force to the second moving body 320 (steady rest device 31), so the first feed mechanism 51 and the second feed mechanism 61 can be configured simply. Also, the first feed mechanism 51 and the second feed mechanism 61 can be installed in a more compact space.

[0077] Furthermore, the first feed mechanism 51 and the second feed mechanism 61 use a rack and pinion structure that is more resistant to chips than a ball screw, making it possible to omit a telescopic cover. In other words, both the first feed mechanism 51 and the second feed mechanism 61 are disposed in the machining area 200 where the workpiece is machined. This increases the proximity of the first movable body 310 (second workpiece spindle 14) and the second movable body 320 (steady rest device 31) in the Z-axis direction.

[0078] In particular, in this embodiment, by increasing the proximity in the Z-axis direction between the first work spindle 12 and the steady rest device 31B, the proximity in the Z-axis direction between the steady rest device 31B and the steady rest device 31A, and the proximity in the Z-axis direction between the steady rest device 31A and the second work spindle 14, it is possible to position the second work spindle 14 closer to the first work spindle 12. This enables a shorter workpiece transfer between the first work spindle 12 and the second work spindle 14.

[0079] The first feed mechanism 51 also has a pair of first pinions 54 (54p, 54q) that are spaced apart from each other in the Z-axis direction and each engage with the rack 52.

[0080] According to this configuration, tension or compression in the Z-axis direction is applied from the pair of first pinions 54 to the rack 52, thereby preventing backlash from occurring between the pair of first pinions 54 and the rack 52. This improves the positioning accuracy of the first movable body 310 (second workpiece spindle 14) in the Z-axis direction.

[0081] The machine tool 100 also has a bracket 71 attached to the bed 21 and on which a rack 52 is provided, a scale unit 86 attached to the bracket 71 and on which a scale is provided, a head unit 87 capable of reading the scale and attached to the first moving body 310 and the second moving body 320 as at least one of the first moving body 310 and the second moving body 320, and further includes a linear scale 85 for detecting the positions of the first moving body 310 and the second moving body 320 in the Z-axis direction.

[0082] According to this configuration, the first feed mechanism 51 performs feedback control using the position information of the first moving body 310 (second work spindle 14) and the second moving body 320 (steady state device 31) detected by the linear scale 85, thereby improving the positioning accuracy of the first moving body 310 (second work spindle 14) and the second moving body 320 (steady state device 31) in the Z-axis direction.

[0083] The tooth surface 52a of the rack 52 faces diagonally downward. This configuration can prevent chips dropping from the machining point of the workpiece from adhering to the tooth surface 52a of the rack 52. Note that the tooth surface 52a of the rack 52 may also be configured to face downward.

[0084] Machine tool 100 also includes a bracket 71 having a top surface 71a extending in the Z-axis direction, attached to bed 21, and on which rack 52 is mounted. Tooth surface 52a of rack 52 is located below top surface 71a and at a position projected onto top surface 71a in the vertical direction.

[0085] With this configuration, the top surface 71a of the bracket 71 functions like an umbrella, covering the tooth surface 52a of the rack 52 from above, thereby more effectively preventing chips from adhering to the tooth surface 52a.

[0086] Bed 21 has a guide surface 23a that is formed on a plane that extends in the Z-axis direction while being inclined relative to the horizontal plane and that guides first moving body 310 and second moving body 320 in the Z-axis direction. Top surface 71a is disposed so as to be flush with guide surface 23a, and extends in the Z-axis direction along the lower edge of guide surface 23a.

[0087] With this configuration, chips adhering to the guide surface 23a can be smoothly discharged from the bed 21 through the top surface 71a.

[0088] The first movable body 310 is the second workpiece spindle 14 as a workpiece spindle. The second movable body 320 is the steady rest device 31. With this configuration, the first feed mechanism 51 and the second feed mechanism 61, which apply driving forces to the second workpiece spindle 14 and the steady rest device 31, respectively, can be simply configured and installed in a more compact space.

[0089] In this embodiment, the first movable body 310 is the second workpiece spindle 14, but the present invention is not limited to this and the first movable body 310 may be a tailstock. The tailstock is disposed opposite the first workpiece spindle 12 in the Z-axis direction in place of the second workpiece spindle 14. The tailstock supports the center of rotation of the workpiece held by the first workpiece spindle 12. In this embodiment, the second movable body 320 is the steady rest 31, but the present invention is not limited to this and the second movable body 320 may be a tool rest provided in a machine tool. The first movable body and the second movable body in the present invention are not particularly limited as long as they are structures that are slidably supported by a bed.

[0090] Furthermore, the machine tool in the present invention is not limited to a lathe, but may be, for example, a multi-tasking machine having both a milling function that processes a workpiece by bringing a rotating tool into contact with a stationary workpiece, and a turning function that processes a workpiece by bringing a tool into contact with a rotating workpiece.

[0091] 5 shows a workpiece W that is held by at least one of the first workpiece spindle 12 and the second workpiece spindle 14 and is rotatable about a central rotation axis 110, a tool rest 16 having a turret 17 that is rotatable about a central rotation axis 160, and a tool T that is attached to the turret 17 via a tool holder 18. The position where the tool T comes into contact with (the outer peripheral surface of) the workpiece W is the machining point of the workpiece W.

[0092] 5 and 7, the rack 52 is attached to the bed 21. The rack 52 is attached to the pedestal 23K. The rack 52 is attached to the pedestal 23K, which is located at the lowest position among the plurality of pedestals 23, 22. The rack 52 is attached to the pedestal 23K via a bracket 71.

[0093] The tooth surface 52a of the rack 52 faces downward or obliquely downward. The tooth surface 52a of the rack 52 is disposed below the guide surface 23a of the base 23K. The bracket 71 is disposed between the rotation center axis 110 (the processing point of the workpiece) and the rack 52 in the vertical direction. The bracket 71 is provided so as to cover the tooth surface 52a of the rack 52 from above. The bracket 71 protrudes further forward than the tooth surface 52a of the rack 52 of the machine tool 100.

[0094] The rack 52 is disposed below the machining point of the workpiece W. The rack 52 is disposed below the rotation center axis 110 of the first workpiece spindle 12 and the second workpiece spindle 14. The rack 52 is disposed below the turning center axis 160 of the turret 17. The rack 52 is disposed between the rotation center axis 110 of the first workpiece spindle 12 and the second workpiece spindle 14 and the turning center axis 160 of the turret 17 in the machine front-to-rear direction of the machine tool 100. The chip conveyor 81 is disposed directly below the rack 52 (see FIG. 9).

[0095] The machine tool 100 in this embodiment includes a movable body 14 / 31 supported by a bed 21 so as to be slidable in a predetermined direction (Z-axis direction), a rack 52 attached to the bed 21 and extending in the Z-axis direction, and a feed mechanism 51 / 61 provided on the movable body 14 / 31 and having a pinion 54 / 63 that rotates while engaging with the rack 52, and that applies a driving force in the predetermined direction (Z-axis direction) to the movable body 14 / 31. A tooth surface 52a of the rack 52 faces downward or diagonally downward.

[0096] With this configuration, chips dropping from the machining point of the workpiece can be prevented from adhering to the tooth surface 52a of the rack 52.

[0097] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0098] 12 First work spindle, 14 Second work spindle, 16 Tool rest, 17 Turret, 18 Tool holder, 21 Bed, 22, 22J, 22K, 23, 23J, 23K Base, 23a Guide surface, 24 Rib, 25 Passage, 31, 31A, 31B Steady rest device, 32 Arm, 33 Roller, 51 First feed mechanism, 52 Rack, 52a Tooth surface, 53, 62 Servo motor, 54, 54p, 54q First pinion, 56, 66 Reducer, 61 Second feed mechanism, 63 Second pinion, 71 Bracket, 71a Top surface, 71b First bottom surface, 71c Second bottom surface, 81 Chip conveyor, 85 Linear scale, 86 Scale unit, 87 Head unit, 91 Brake mechanism, 92 Brake pad, 100 Machine tool, 110,120,130,140,150 rotation center axis, 160 swivel center axis, 200 machining area, 310 first moving body, 320 second moving body, 400 control device, 410 numerical control device, 420 servo driver, W workpiece, T tool.

Claims

1. a first moving body supported by the bed so as to be slidable in a predetermined direction; a second movable body supported by the bed so as to be slidable in the predetermined direction; a first feed mechanism including a rack extending in the predetermined direction and a first pinion provided on the first moving body and rotating while engaging with the rack, the first feed mechanism applying a driving force in the predetermined direction to the first moving body; a second feed mechanism including the rack shared with the first feed mechanism and a second pinion provided on the second movable body and rotating while engaging with the rack, and applying a driving force in the predetermined direction to the second movable body; the first movable body is a work spindle or a tailstock, The machine tool, wherein the second movable body is a steady rest or a tool rest.

2. 2. The machine tool according to claim 1, wherein the first feed mechanism has a pair of the first pinions arranged at an interval in the predetermined direction, each of the first pinions engaging with the rack.

3. A first movable body supported by a bed so as to be slidable in a predetermined direction; a second movable body supported by the bed so as to be slidable in the predetermined direction; a first feed mechanism including a rack extending in the predetermined direction and a first pinion provided on the first moving body and rotating while engaging with the rack, the first feed mechanism applying a driving force in the predetermined direction to the first moving body; a second feed mechanism including the rack shared with the first feed mechanism and a second pinion provided on the second movable body and rotating while engaging with the rack, the second feed mechanism applying a driving force in the predetermined direction to the second movable body; a bracket attached to the bed and on which the rack is mounted; A machine tool comprising: a scale unit attached to the bracket and having a scale provided thereon; a head unit capable of reading the scale and attached to at least one of the first movable body and the second movable body; and a linear scale for detecting the position of the movable body in the specified direction.

4. A first movable body supported by a bed so as to be slidable in a predetermined direction; a second movable body supported by the bed so as to be slidable in the predetermined direction; a first feed mechanism including a rack extending in the predetermined direction and a first pinion provided on the first moving body and rotating while engaging with the rack, the first feed mechanism applying a driving force in the predetermined direction to the first moving body; a second feed mechanism including the rack shared with the first feed mechanism and a second pinion provided on the second movable body and rotating while engaging with the rack, and applying a driving force in the predetermined direction to the second movable body; The tooth surface of the rack faces downward or obliquely downward, and a bracket having a top surface extending in the predetermined direction, attached to the bed, and on which the rack is provided; A machine tool, wherein the tooth surface of the rack is positioned below the top surface and at a position projected onto the top surface in the vertical direction.

5. the bed is formed of a plane that extends in the predetermined direction while being inclined with respect to a horizontal plane, and has a guide surface that guides the first moving body and the second moving body in the predetermined direction; The machine tool according to claim 4 , wherein the top surface is disposed so as to be flush with the guide surface and extends in the predetermined direction along a lower edge of the guide surface.

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