lathe

Abstract

This invention provides a lathe with high machining accuracy. The lathe of this invention includes: a first spindle (31) that holds a workpiece (W1) and is rotatable about a centerline (CL1) of the first spindle; a first tool post (5) on which a tool (T1) is mounted, the tool (T1) machining the workpiece (W1) by cutting into the workpiece (W1) held by the first spindle (31); an X1-axis ball screw (502) extending upward in an X1-axis orthogonal to the centerline (CL1) of the first spindle, causing the first tool post (5) to move upward in the X1-axis; and an X1-axis support bearing (…). 504), configured on one end of the X1 axis ball screw (502), restricting the movement of the X1 axis ball screw (502) in the X1 axis; the first tool holder (5) has an X1 axis ball screw nut (512), which engages with the X1 axis ball screw (502) and moves along the X1 axis by rotating the X1 axis ball screw (502); and the cutting direction of the tool (T1) is the direction in which the X1 axis ball screw nut (512) approaches the X1 axis support bearing (504).

Description

Technical Field

[0001] This invention relates to a lathe equipped with a spindle and a tool post. Background Technology

[0002] A lathe is known to include: a spindle that holds a workpiece and is rotatable; and a tool post equipped with a tool for machining the workpiece held by the spindle (for example, see Patent Document 1, etc.). The lathe described in Patent Document 1 machines a workpiece held and rotating by the spindle by moving the tool post in the cutting direction in which the tool cuts into the workpiece. The tool post is provided with a driven part. Furthermore, the driven part engages with a drive shaft, the axial movement of which is limited by a movement limiting part. The driven part moves along the drive shaft in its own axis by rotating the drive shaft about its own axis. Since the axis of the drive shaft is in the cutting direction, if the drive shaft is rotated by a motor, the tool post will move in the cutting direction or in the opposite direction to the cutting direction, depending on the direction of rotation.

[0003] [Background Technical Documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-509489 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] However, regarding the lathe described in Patent Document 1, when the tool post moves in the cutting direction and the tool cuts into the workpiece, the moving limiting part that restricts the movement of the drive shaft is greatly separated from the driven part of the tool post. As a result, the drive shaft extends and retracts along its axial direction due to heat, and the cutting depth of the tool changes, leading to a decrease in machining accuracy.

[0008] The present invention was made in view of the aforementioned problem, and its object is to provide a lathe with high machining accuracy.

[0009] [Technical means to solve the problem]

[0010] The lathe of the present invention, which achieves the aforementioned objective, is characterized by comprising:

[0011] The spindle holds the workpiece and can rotate about the spindle centerline.

[0012] A tool holder, equipped with a tool that processes the workpiece by cutting into it and holding it in place by the spindle;

[0013] A drive shaft extends in an axis orthogonal to the centerline of the spindle, causing the tool holder to move in that axis; and

[0014] A movement limiting part is disposed at one end of the drive shaft along the axial direction, thereby limiting the movement of the drive shaft along that axial direction; and

[0015] The tool holder has a driven part that engages with the drive shaft and moves along the axial direction by rotation of the drive shaft; and

[0016] The cutting direction of the tool is the direction in which the driven part moves toward the movement limiting part.

[0017] According to this lathe, if the tool moves in the cutting direction, the driven part moves closer to the movement limiting part, so that when machining the workpiece, the movement limiting part and the driven part are positioned close to each other. In this way, even if the drive shaft extends or retracts axially due to heat, the cutting depth of the tool on the workpiece is less likely to change, thus improving the machining accuracy of the workpiece.

[0018] Here, the lathe may also include a guide sleeve located in front of the spindle, which rotatably supports the workpiece about the spindle's centerline. Additionally, the drive shaft may be a ball screw, and the driven part may be a ball screw nut engaged with the ball screw. Furthermore, the movement limiting part may be a rolling bearing. Besides, the lathe may also include a motor that rotates the drive shaft; the cutting direction of the tool may also be the direction in which the driven part approaches the motor. Furthermore, the output shaft of the motor and the drive shaft may be arranged on the same axis.

[0019] The lathe can also be configured such that the driven part is located on the cutting direction side of the tool post.

[0020] In this way, the driven part is positioned close to the movement restriction part, so even if the drive shaft extends or retracts in its axial direction, the cutting depth of the tool on the workpiece is not easily changed. Therefore, the machining accuracy of the workpiece is further improved.

[0021] The lathe can also be configured as follows, namely, equipped with a motor to rotate the drive shaft; and

[0022] The motor is positioned closer to the cutting direction side than the tool holder.

[0023] If the motor is positioned closer to the side opposite to the cutting direction than the tool post, then the tool post and the motor are arranged side-by-side on one side of the spindle that holds the workpiece, making the lathe prone to becoming large. By configuring it as described above, the lathe can be made smaller.

[0024] Alternatively, the lathe can also be configured such that it includes a motor for rotating the drive shaft; and

[0025] The tool post is positioned closer to the back side of the lathe than the spindle centerline;

[0026] The motor is positioned closer to the front side of the lathe than the tool post.

[0027] If the tool post is positioned closer to the back side than the spindle centerline, and the motor is positioned closer to the back side than the tool post, the motor or its support structure will protrude towards the back side, making the lathe prone to becoming large. According to this embodiment, by positioning the motor closer to the front side than the tool post, the lathe can be made smaller.

[0028] Alternatively, the lathe can also be configured such that it includes a motor for rotating the drive shaft; and

[0029] The tool post is positioned closer to the front side of the lathe than the spindle centerline;

[0030] The motor is positioned closer to the back side of the lathe than the tool post.

[0031] If the tool post is positioned closer to the front side than the spindle centerline, and the motor is positioned closer to that front side than the tool post, the motor or its support structure will protrude towards the front side, making the lathe prone to becoming large. According to this embodiment, by positioning the motor closer to the back side than the tool post, the lathe can be made smaller.

[0032] Here, the motor can also be positioned higher up than the spindle. Alternatively, the motor can also be a servo motor.

[0033] [Invention Effects]

[0034] According to the present invention, a lathe with high machining accuracy can be provided. Attached Figure Description

[0035] Figure 1 This is a perspective view showing the appearance of the NC lathe related to this embodiment.

[0036] Figure 2 It means Figure 1 The front view of the NC lathe shown.

[0037] Figure 3 It is a simple representation Figure 1The diagram shows a top view of the internal structure of an NC lathe.

[0038] Figure 4 It means Figure 1 The rear view of the NC lathe shown.

[0039] Figure 5 It is viewed from a slightly above and below the front side. Figure 4 The diagram shows a three-dimensional view of the distribution panel room.

[0040] Figure 6 It is cut off Figure 1 The front view of the NC lathe shown shows the exterior portion of the front side, followed by the interior front view.

[0041] Figure 7 From Figure 2 right side observation Figure 1 The right view of the tool post holder, the first tool post, and the guide sleeve of the NC lathe shown.

[0042] Figure 8(a) is a simplified representation Figure 1 The diagram shows a top view of the tool post holder and the lower part of the first tool post of the NC lathe.

[0043] Figure 8(b) is a top view showing the situation after the intermediate seat is moved towards the -X1 direction from the state in Figure 8(a).

[0044] Figure 9 This represents an example of changes in an NC lathe. Figure 7 Same right view. Detailed Implementation

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this embodiment, the application of the present invention to an NC (Numerical Control) lathe will be used as an example for explanation.

[0046] Figure 1 This is a perspective view showing the appearance of the NC lathe related to this embodiment. Additionally, Figure 2 It means Figure 1 The front view of the NC lathe shown.

[0047] like Figure 1 and Figure 2 As shown, the NC lathe 1 includes a cutting chamber 11, a spindle table chamber 12, and an operation panel 15 mounted on a bracket that serves as a base. This NC lathe 1 is an example of a lathe. Furthermore, in Figure 1 In the diagram, the left side near the front shows the front view of NC lathe 1, and the right side inside shows the back view of NC lathe 1. Furthermore, Figure 2The downstream end of the discharge conveyor 9 is also shown, which is responsible for transporting the workpieces processed by the NC lathe 1 to the outside of the NC lathe 1. Viewed from the front, the cutting chamber 11 is located on the right side of the NC lathe 1. A window 111 is provided on the front side of the cutting chamber 11 for viewing its interior. Viewed from the front, the spindle table chamber 12 is located on the left side of the NC lathe 1. The cutting chamber 11 is separated from the spindle table chamber 12, and a guide sleeve support table 41 (described later) is disposed between them. Figure 3 ) or the first tool holder 5 (refer to) Figure 3 Hereinafter, the portion between the cutting chamber 11 and the spindle chamber 12 will be referred to as the intermediate portion. The front side of the intermediate portion is covered by the tool post front cover 131. In addition, the upper end of the intermediate portion is covered by the tool post top cover 132. A plurality of vent holes 1322 are formed in the tool post top cover 132. Furthermore, the tool post front cover 131 and the tool post top cover 132 extend slightly from the intermediate portion toward the cutting chamber 11. Therefore, the tool post front cover 131 and the tool post top cover 132 also cover Figure 2 The cutting chamber 11 is located at the left end. The operation panel 15 is positioned above the spindle table chamber 12. This operation panel 15 is the input device for operating the NC lathe 1. The operator of the NC lathe 1 operates the NC lathe 1 by observing the cutting chamber 11 through the window 111 to confirm the machining operation, etc. At this time, the operator may repeatedly observe the cutting chamber 11 and operate the operation panel 15 to adjust the machining operation. In the tool post front cover 131 of this embodiment, since a large chamfer shape 131a is formed between the front portion extending to the front side of the tool post front cover 131 and the side portion on the operation panel 15 side, the operator of the NC lathe 1 is not easily obstructed by the tool post front cover 131 when moving their line of sight from the cutting chamber 11 to the operation panel 15 or from the operation panel 15 to the cutting chamber 11, and can quickly move their line of sight. In addition, when the operator of the NC lathe 1 reaches out to operate the control panel 15 while observing the window 111, or moves his hand from the cutting chamber 11 side to the control panel 15 side and reaches out to the control panel 15, the hand movement is not easily hindered by the tool post front cover 131, thus improving the operability of the NC lathe 1.

[0048] Figure 3 It is a simple representation Figure 1 The diagram shows a top view of the internal structure of an NC lathe.

[0049] like Figure 3As shown, the NC lathe 1 is equipped with an NC device 2, a first spindle head 3, a guide sleeve 4, a first tool post 5, a second spindle head 6, and a second spindle tool post 7. The NC device 2 stores an NC program. The NC device 2 is a computer that moves the first spindle head 3, the first tool post 5, the second spindle head 6, and the second spindle tool post 7 by numerical control according to this NC program. Furthermore, the first tool post 5 may sometimes be equipped with a rotary tool that rotates tool T1 itself, and similarly, the second spindle tool post 7 may sometimes be equipped with a rotary tool that rotates tool T2 itself. In this case, the NC device 2 also controls the rotation of the rotary tools. In addition to the NC device 2 using the NC program to perform the operation, it can also be controlled by... Figure 1 The operation panel 15 shown inputs direct commands to the NC device 2 to make the NC lathe 1 move.

[0050] The first spindle stage 3 is configured in Figure 1 The spindle stage chamber 12 is shown. A first spindle 31 is mounted in the first spindle stage 3. This first spindle 31 is an example of a spindle. The first spindle stage 3 can move upwards along the Z1 axis together with the first spindle 31. The Z1 axis is horizontal, and... Figure 3 The center represents the left-right direction. In the following explanations, for ease of clarification, we will... Figure 3 The right side of the middle is used as "front". Figure 3 The left side is referred to as "rear" in the description. Furthermore, in this NC lathe 1, the forward direction aligns with the +Z1 direction, and the rearward direction aligns with the -Z1 direction. The first spindle 31 has a first holding portion, such as a chuck, at its front end. The first spindle 31 can releasably hold a rod-shaped workpiece W1 inserted into its interior from its rear end via the first holding portion. The first spindle 31 holds the workpiece W1 and is capable of rotating about the first spindle centerline CL1. This first spindle centerline CL1 is an example of a spindle center line. The direction of the first spindle centerline CL1 aligns with the Z1 axis. A motor, such as a built-in motor, is provided in the first spindle 31. This motor receives commands from the NC device 2, causing the first spindle 31 to rotate about the first spindle centerline CL1. Thus, the workpiece W1 held by the first spindle 31 rotates about the first spindle centerline CL1.

[0051] The guide sleeve 4 is fixed to the bracket of the NC lathe 1 in front of the first spindle 31 by a guide sleeve support 41. The guide sleeve 4 supports the front end of the workpiece W1 that passes through the interior of the first spindle 31, allowing it to slide freely along the Z1 axis. The portion of the guide sleeve 4 that supports the workpiece W1 can rotate synchronously with the first spindle 31 around the center line CL1 of the first spindle. That is, the center line CL1 of the first spindle is also the rotation center line of the workpiece W1 supported by the guide sleeve 4. Since the deflection of the workpiece W1 during machining is suppressed by the guide sleeve 4, it is possible to machine particularly slender workpieces W1 with high precision. In addition, the front surface portion of the guide sleeve 4 is exposed inside the cutting chamber 11.

[0052] The first tool post 5 is positioned closer to the back side of the NC lathe 1 than the center line CL1 of the first spindle. This first tool post 5 is movable in the X1 axis (orthogonal to the Z1 axis and facing horizontally) and the Y1 axis (facing vertically). This first tool post 5 is an example of a tool post. Figure 3 In the middle, the vertical direction is the X1 axis, and the direction orthogonal to the paper plane is the Y1 axis. The first tool holder 5 is equipped with the tool T1 for machining workpiece W1. Figure 3 The diagram shows the first tool post 5 with tools T1 mounted on it. In the first tool post 5, various tools T1, including tools for external diameter machining and cutting-off machining, are mounted side-by-side along the Y1 axis. This is achieved by using the first tool post stage 52 (described later) provided on the first tool post 5. Figure 7 The tool T1 moves upward along the Y1 axis, selecting any tool T1 from among the various tools T1. Furthermore, by moving the first tool post 5 in the cutting direction, the tool T1 cuts into the workpiece W1 held by the first spindle 31 and processes the workpiece W1. In this embodiment, the cutting direction of the tool T1 is the frontal direction of the NC lathe 1. Figure 3 The direction is represented as -X1. The configuration of the first tool post 5 will be described in detail later. In addition, most of the first tool post 5, except for the front part, is located in the middle part, and the front part and the tool T1 are located in the cutting chamber 11.

[0053] The second spindle stage 6 is positioned closer to the front than the guide sleeve 4, and Figure 1Inside the cutting chamber 11 shown, a second spindle 61 is mounted in a second spindle table 6. The second spindle table 6 can move together with the second spindle 61 in the X2 and Z2 axes. The X2 axis is in the same direction as the X1 axis, and the Z2 axis is in the same direction as the Z1 axis. The second spindle 61 has a second holding part, such as a chuck, at its rear end. When the front end of the workpiece W1, which has been machined using the first spindle 31, is clamped by the second spindle 61, the first spindle 31 and the second spindle 61 are rotated synchronously, and a cutting-off action is performed using a cutting-off tool. Alternatively, when the workpiece, which has been machined using the first spindle 31, is clamped by the second spindle 61, the second spindle 61 is rotated with the chuck of the first spindle 31 open, and a cutting-off action is performed using a cutting-off tool. In this way, the cut-off workpiece W2 is handed over to the second spindle 61. The second spindle 61 can be releasably held by the second holding part for the cut workpiece W2 received from the first spindle 31. The second spindle 61 can rotate around the second spindle centerline CL2 while holding the cut workpiece W2. The direction of the second spindle centerline CL2 is aligned with the Z2 axis. A motor, such as a built-in motor, is provided in the second spindle 61. This motor receives commands from the NC device 2 to cause the second spindle 61 to rotate around the second spindle centerline CL2. In this way, the cut workpiece W2 held by the second spindle 61 rotates around the second spindle centerline CL2. Furthermore, since the second spindle 61 and the first spindle 31 are arranged symmetrically opposite each other, they are sometimes referred to as opposing spindles.

[0054] The second spindle tool post 7 is positioned slightly in front of the guide sleeve 4 and offset towards the front side of the NC lathe 1 relative to the center line CL1 of the guide sleeve 4 and the first spindle. The second spindle tool post 7 is movable along the Y2 axis, which is the same direction as the Y1 axis. The second spindle tool post 7 is equipped with a tool T2, which processes the cut-off workpiece W2 held by the second spindle 61. Figure 3 The diagram shows the second spindle tool post 7 with tool T2 mounted on it. Additionally, the second spindle tool post 7 also includes a receiving device (not shown) for receiving machined workpieces. Various tools T2, such as drills or end mills, are mounted side-by-side in the second spindle tool post 7. Furthermore, Figure 3 Although not explicitly stated, tools T2 are mounted side-by-side not only along the X2 axis but also along the Y2 axis. By moving the second spindle tool holder 7 along the Y2 axis, any tool T2 can be selected from these various tools T2. Furthermore, by moving the second spindle head 6 in the -Z direction, the rear end portion of the cut-off workpiece W2, held by the second spindle 61, is machined. Additionally, the second spindle tool holder 7 is positioned in... Figure 1 Inside the cutting chamber 11 shown.

[0055] Figure 4 It means Figure 1 The rear view of the NC lathe shown.

[0056] like Figure 4 As shown, a switchboard compartment 14 is provided on the lower part of the back of the NC lathe 1. Generally, the switchboard compartment 14 is covered by a switchboard cover 141. Figure 4 The diagram shows the distribution panel cover 141 removed and moved to the right side of the figure as indicated by the arrow. Figure 4 As shown in the enlarged and circled figure, the distribution panel compartment 14 contains multiple electrical installation units 142, which are modular units composed of amplifiers or controllers, etc. These electrical installation units 142 are screwed into... Figure 4 The paper surface near the front side is in the middle, and by removing the screw, the electrical assembly unit 142 can be pulled out. Figure 4 The paper is located near the front side. This allows the necessary electrical unit 142 to be removed from the distribution panel 14 when maintenance or malfunction occurs. Furthermore, these electrical units 142 are connected to cables 143, which connect to various actuators or electrical components located on the NC lathe 1. Additionally, in... Figure 4 In the diagram, only the portion of cable 143 located near the distribution panel 14 is shown; the remaining portion is omitted. Cable 143 passes through two cable entry sections 145 located on each of the left and right sides of the distribution panel 14 and connects to the electrical installation unit 142 within the distribution panel 14.

[0057] Figure 5 It is viewed from a slightly above and below the front side. Figure 4 The diagram shows a three-dimensional view of the distribution panel room.

[0058] like Figure 5 As shown, the cable inlet 145 includes an inlet stop 1451, an upper retainer 1452, and a lower retainer 1453. The inlet stop 1451, upper retainer 1452, and lower retainer 1453 are fixed to the side of the distribution panel 14 by screws. The upper retainer 1452 and lower retainer 1453 are arranged opposite each other in the vertical direction, and the opposing portions are each formed by a sponge-like component. The cable 143 is clamped between the sponge-like components of the upper retainer 1452 and the lower retainer 1453. Furthermore, the lower retainer 1453 is provided with a retaining fitting, which has an Ω-shaped groove for securing the portion of the cable 143 pulled out to the outside of the distribution panel 14 using a strap. After the inlet stop 1451 is removed from the distribution panel 14, the lower retainer 1453 can be pulled out of the distribution panel 14 by removing the screws. Figure 5The diagram shows the situation where the inlet stop 1451 is removed and the lower retainer 1453 of the upper cable inlet portion 145 is pulled out. By configuring it so that the lower retainer 1453 can be removed from the distribution panel compartment 14, when the electrical assembly unit 142 (see reference) is moved... Figure 4 When the electrical unit located near the side is pulled out of the distribution panel 14, it is prevented from being obstructed by the cable 143. In other words, the electrical unit 142 can be easily pulled out from the distribution panel 14, thus improving maintainability.

[0059] Figure 6 It is cut off Figure 1 The front view of the NC lathe shown shows the exterior portion of the front side, followed by the interior front view.

[0060] like Figure 6 As shown, the upper end of the first tool post 5 is covered by the tool post top cover 132. Additionally, an intermediate wall 133 is formed between the cutting chamber 11 and the intermediate section. Within the cutting chamber 11, a large amount of coolant is sprayed onto the machining area to facilitate machining and to cool the heat generated during machining. The coolant sprayed into the cutting chamber 11 is recovered and recycled within the NC lathe 1. The intermediate section and the cutting chamber 11 are separated from the front surface of the first tool post 5 by the intermediate wall 133. Therefore, coolant flow into the intermediate section or the spindle chamber 12 side is essentially prevented. However, sometimes liquid or mist-like coolant may seep into the tool post top cover 132 through the gap located at the upper end of the first tool post 5. As described above, a plurality of vent holes 1322 are formed in the tool post top cover 132 to expel air from inside the NC lathe 1. Therefore, if coolant seeps into the tool post top cover 132, there is a concern that the coolant may flow to the outside of the NC lathe 1, sometimes causing an unpleasant odor or stickiness around the area where the NC lathe 1 is located. Additionally, there is a concern that coolant may flow into the spindle chamber 12 via the intermediate section. If coolant flows into the spindle chamber 12, it will not only reduce the speed of the lathe but also... Figure 3 The lifespan of the first spindle head 3 or the first spindle 31 shown is potentially limited, and there are concerns that these first spindle heads 3 or the first spindle 31 may become sticky and difficult to maintain. In this embodiment, a partition plate 1321 is formed near the center of the tool post top cover 132 along the Z1 axis, hanging down from the top surface of the tool post top cover 132, and a vent hole 1322 is formed only in the portion further rearward (in the -Z1 direction) than the partition plate 1321. In this way, even if coolant seeps into the tool post top cover 132, it will be blocked by the partition plate 1321, and the coolant will not easily enter the portion further rearward than the partition plate 1321. As a result, coolant flow to the outside of the NC lathe 1 or coolant flow into the spindle head chamber 12 is suppressed.

[0061] Figure 7 From Figure 2 right side observation Figure 1 The image shows a right view of the tool post holder, the first tool post, and the guide bushing of an NC lathe. Furthermore, this... Figure 7 The lines showing the outline of the NC lathe 1 are represented by dashed lines.

[0062] like Figure 7 As shown, the first tool post 5 is mounted on the tool post base 50. The first tool post 5 includes: a first intermediate seat 51, which is movable upward in the X1 axis; and a first tool post table 52, mounted on the first intermediate seat 51, which is movable upward in the Y1 axis. The first tool post table 52 is positioned closer to the front than the first intermediate seat 51. Figure 7 In the diagram, the direction orthogonal to the paper surface is the Z1 axis, and the side closest to the front of the paper surface is the front side. The first intermediate seat 51 of the first tool holder 5 is located in the middle, and the front part of the first tool holder 52 is located inside the cutting chamber 11. The tool holder 50 is fixed on a bracket (not shown) that serves as a base. The first intermediate seat 51 is movably mounted on the tool holder 50 in the X1 axis. The first tool holder 52 is movably mounted on the first intermediate seat 51 in the Y1 axis. The first tool holder 52 is fixed with a Y1 axis ball screw nut (not shown). The output shaft of the Y1 axis motor (not shown) is connected to a Y1 axis ball screw (not shown). The Y1 axis ball screw has a helical groove formed on its outer circumference. In the Y1 axis ball screw nut, the internal balls circulate and engage (screw) with the groove provided on the Y1 axis ball screw. Furthermore, by driving the Y1 axis motor (not shown), the Y1 axis ball screw is rotated, and the first tool post 52 moves upward along the Y1 axis. Figure 7 The diagram shows the first tool post 52 located at the origin along the Y1 axis. Furthermore, the tool post 50 and the guide sleeve support 41 can also be configured as a single unit.

[0063] An X1-axis motor 501 is fixed to the tool post 50. This X1-axis motor 501 is an example of a motor. The X1-axis motor 501 is positioned closer to the front side of the NC lathe 1 than the first tool post 5. Furthermore, the X1-axis motor 501 is positioned between the guide sleeve 4 and the first spindle 31 (see reference). Figure 3The X1 output shaft 5011 of the X1 axis motor 501 (see Figures 8(a) and (b)) is connected to an X1 axis ball screw 502 disposed on the same axis. This connection structure will be described in detail later. By supplying power to the stator within the X1 axis motor 501, the X1 output shaft 5011 rotates together with the rotor, causing the X1 axis ball screw 502 connected to the X1 output shaft 5011 to rotate. The X1 axis ball screw 502 extends in a direction orthogonal to the center line CL1 of the first main shaft, and has a helical groove formed on its outer circumference. Specifically, the X1 axis ball screw 502 extends upward in the X1 axis. This X1 axis corresponds to an example of an axial direction, and the X1 axis ball screw 502 corresponds to an example of a drive shaft. The first intermediate seat 51 has an X1 axis ball screw nut 512. This X1 axis ball screw nut 512 corresponds to an example of a driven part. In the X1 axis ball screw nut 512, the internal balls circulate and engage with the slots provided in the X1 axis ball screw 502. Furthermore, by driving the X1 axis motor 501 to rotate the X1 axis ball screw 502, the first intermediate seat 51 moves upward in the X1 axis. Figure 7 The diagram shows the first intermediate seat 51 located at the origin along the X1 axis.

[0064] Next, we will explain the structure and operation of the first tool holder in more detail.

[0065] Figure 8(a) is a simplified representation Figure 1 The diagram shows a top view of the tool post holder and the lower part of the first tool post of the NC lathe. In Figure 8(a), with... Figure 7 Similarly, the case where the intermediate seat is located at the origin in the X1 axis is shown. In addition, Figure 8(b) is a top view showing the case after the intermediate seat is moved in the -X1 direction from the state of Figure 8(a). Furthermore, in Figure 8(a), the guide sleeve 4 and the workpiece W1 are represented by dashed lines, and in Figure 8(b), the guide sleeve 4 and the cut workpiece W2 are represented by dashed lines.

[0066] As shown in Figure 8(a), the first tool post 52 includes: a base 520, a tool fixing part 521 for fixing the tool T1, and a Y1-axis sliding part 522. The base 520 is the foundation component of the first tool post 52, on which the tool fixing part 521 and the Y1-axis sliding part 522 are fixed. In addition, the first intermediate seat 51, besides having the Y1-axis motor and the X1-axis ball screw nut 512, also includes a seat base 510, an X1-axis sliding part 513, and a Y1-axis track 514. The seat base 510 is the foundation component of the first intermediate seat 51, on which the other components of the first intermediate seat 51 are fixed. The Y1-axis track 514 extends upward along the Y1-axis, orthogonal to the plane of the paper in Figure 8(a). The Y1-axis sliding part 522 is slidably mounted on this Y1-axis track 514. In this way, the first tool post 52 is configured to move freely in the Y1 axis relative to the first intermediate seat 51, and moves in the Y1 axis as described above by the drive of the Y1 axis motor.

[0067] Additionally, the tool holder 50 is fixed with an X1-axis track 505. The X1-axis track 505 extends upward in the X1-axis direction. An X1-axis sliding portion 513 is slidably mounted on the X1-axis track 505. In this way, the first intermediate seat 51 is configured to move freely in the X1-axis direction relative to the tool holder 50. An X1-axis coupling 503 is disposed within the tool holder 50. The X1-axis coupling 503 connects the X1 output shaft 5011 of the X1-axis motor 501 to the X1-axis ball screw 502. Furthermore, an X1-axis support bearing 504 is also disposed within the tool holder 50. This X1-axis support bearing 504 is an example of a movement limiting part. The X1-axis support bearing 504 is disposed on one end portion of the X1-axis ball screw 502 in the axial direction. The X1-axis support bearing 504 is a so-called rolling bearing having rolling elements between the outer and inner wheels. Furthermore, the outer wheel of the X1-axis support bearing 504 is fixed to the tool holder 50, and the inner wheel contains the X1-axis ball screw 502. Thus, the X1-axis ball screw 502 is rotatably fixed to the tool holder 50 with respect to the X1-axis. In other words, all movement of the X1-axis ball screw 502, except for rotation around the X1-axis, is restricted by the X1-axis support bearing 504. By rotating the X1-axis ball screw 502 with its movement restricted in the X1-axis direction, the X1-axis ball screw nut 512, engaged with the X1-axis ball screw 502, moves in the +X1 or -X1 direction depending on the direction of rotation. Consequently, the first intermediate seat 51 and the first tool holder 52 move together in the same direction as the X1-axis ball screw nut 512. That is, the first tool holder 5 moves in the +X1 or -X1 direction.

[0068] As shown in Figure 8(b), if the X1 axis motor 501 is driven to move the first tool holder 5 in the -X direction, then the tool T1 cuts into the workpiece W1. That is, the -X direction corresponds to an example of the cutting direction. The -X direction is the direction in which the X1 axis ball screw nut 512 approaches the X1 axis support bearing 504. Additionally, the -X direction is also the direction in which the X1 axis ball screw nut 512 approaches the X1 axis motor 501. Using a cutting-off tool as tool T1, the workpiece W1 is cut off by bringing the tip of the cutting-off tool to the center line CL1 of the first spindle. Figure 8(b) shows the case where the tip of tool T1 reaches the center line CL1 of the first spindle, cutting off the front portion of the workpiece W1 to become the cut-off workpiece W2. Furthermore, generally speaking, by making the tool T1 cut off before cutting off the workpiece W1... Figure 3 The second spindle 61, as shown, holds the front portion of workpiece W1 before cutting it off, thereby transferring the cut-off workpiece W2 to the second spindle 61. Furthermore, when machining the rear (-Z side) portion of the cut-off workpiece W2, the cut-off workpiece W2 is held by the second spindle 61 and... Figure 3 The tool T2 shown is used to process the rear part.

[0069] According to the NC lathe 1 of this embodiment, if the tool T1 moves in the cutting direction, the X1-axis ball screw nut 512 moves closer to the X1-axis support bearing 504. Therefore, when machining the workpiece W1, the X1-axis support bearing 504 and the X1-axis support bearing 504 are positioned close to each other. In other words, in the NC lathe 1 of this embodiment, when the tool T1 contacts the workpiece W1 for machining, the X1-axis ball screw nut 512 moves closer to the X1-axis support bearing 504. When machining the workpiece W1, frictional heat and other heat are generated during the cutting process, sometimes causing the X1-axis ball screw 502 to extend slightly upward in the X1-axis direction. In addition, generally, multiple products are manufactured from the long workpiece W1 during the period from the start to the end of machining. Therefore, the length of the X1-axis ball screw 502 is somewhat different in the early and late stages of machining, and the cutting depth of the tool T1 may sometimes change. In the NC lathe 1 described earlier, even if the X1-axis ball screw 502 expands and contracts along its X1 axis due to heat, the cutting depth of the tool T1 is not easily changed during machining because the X1-axis ball screw nut 512 and the X1-axis support bearing 504 are close to each other. As a result, the machining accuracy of the workpiece W1 can be improved. Furthermore, if the X1-axis motor 501 is positioned closer to the back side than the first tool post 5, the X1-axis motor 501 or its support structure will protrude towards the back side, making the NC lathe 1 prone to becoming larger. In other words, if the X1-axis motor 501 is positioned closer to the side opposite to the cutting direction of the tool T1 than the first tool post 5, the first tool post 5 and the X1-axis motor 501 become arranged side-by-side closer to the back side than the first spindle, thus making the NC lathe 1 prone to becoming larger. In the NC lathe 1 of this embodiment, the NC lathe 1 is made smaller because the first tool post 5 is positioned closer to the back side of the NC lathe 1 than the center line CL1 of the first spindle, and the X1-axis motor 501 is positioned closer to the front side of the NC lathe 1 than the first tool post 5. In other words, the NC lathe 1 is made smaller by positioning the X1-axis motor 501 closer to the cutting direction side of the tool T1 than the first tool post 5. Furthermore, since the X1-axis ball screw nut 512 is positioned on the front side (cutting direction side) of the first tool post 5 where the X1-axis motor 501 or the X1-axis support bearing 50 is located, the first intermediate seat 51 can move upward in the X1-axis direction even if the X1-axis ball screw 502 is short. In addition, since the X1-axis ball screw nut 512 is positioned on the front side of the first tool holder 5, and thus close to the X1-axis support bearing 504, the cutting depth of the tool T1 on the workpiece W1 is less likely to change even if the X1-axis ball screw 502 extends or retracts in its axial direction. This further improves the machining accuracy of the workpiece W1.Furthermore, since the cutting tip of tool T1 is configured to overlap with the X1-axis ball screw nut 512 in the X1 axis, even if the base 510 or the first tool post 52 located between the X1-axis ball screw nut 512 and tool T1 expands or contracts in the X1 axis due to heat, the cutting tip of tool T1, as the machining position, is not easily affected by the expansion or contraction. This also improves machining accuracy. In addition, as long as the cutting tip of tool T1 and the X1-axis ball screw nut 512 are located close to each other in the X1 axis, machining accuracy will be improved. By making the cutting tip of tool T1 overlap with the X1-axis ball screw nut 512 in the X1 axis, machining accuracy is further improved.

[0070] Next, regarding the variation of the NC lathe 1 described above, in the following description, for components with the same names as those described above, the same symbols as those used above will be attached, and repeated descriptions will sometimes be omitted.

[0071] Figure 9 This represents an example of changes in an NC lathe. Figure 7 The same right view. Furthermore, in this... Figure 9 In the diagram, the X1 axis coupling 503, the X1 axis support bearing 504, and the X1 output shaft 5011 are all represented by double-dotted lines.

[0072] like Figure 9 As shown, the main difference between this variant of the NC lathe 1 and the X1 axis motor 501 lies in the positional relationship between the first tool post 5 and the X1 axis motor 501. Figure 7 The NC lathe 1 shown is an example of a variation where a first tool post 5 is positioned on the front side of the NC lathe 1. An X1-axis motor 501 is positioned closer to the back side of the NC lathe 1 than the first tool post 5. Furthermore, the X1-axis motor 501 is positioned between the guide sleeve 4 and the first spindle 31 (see reference). Figure 3 (More closely above.) The X1 output shaft 5011 of the X1 axis motor 501 is connected to an X1 axis ball screw 502 arranged on the same axis. The X1 axis ball screw 502 extends upward along the X1 axis, which is orthogonal to the center line CL1 of the first main shaft, and has a helical groove formed on its outer periphery. Figure 9 The image shows the case where the first intermediate seat 51 is located at the origin in the X1 axis.

[0073] If the X1 axis motor 501 is driven to move the first tool post 5 from... Figure 9Moving the indicated position towards the +X direction, tool T1 cuts into workpiece W1. In other words, in this variation, the +X direction corresponds to an example of the cutting direction. The +X direction is the direction in which the X1-axis ball screw nut 512 approaches the X1-axis support bearing 504. Additionally, the +X direction is also the direction in which the X1-axis ball screw nut 512 approaches the X1-axis motor 501. In the variation described above, the X1-axis ball screw nut 512 is also positioned on the cutting direction side of the first tool post 5. Furthermore, the X1-axis motor 501 is positioned closer to the cutting direction side than the first tool post 5. Moreover, the first tool post 5 is positioned closer to the front side of the NC lathe 1 than the first spindle centerline CL1, and the X1-axis motor 501 is positioned closer to the back side of the lathe than the first tool post 5. This variation also achieves the same effect as the previous embodiment.

[0074] The present invention can be varied within the scope of the claims without being limited to the described embodiments. For example, in this embodiment, the X1 output shaft 5011 of the X1 axis motor 501 and the X1 axis ball screw 502 are arranged on the same axis and directly connected by the X1 axis coupling 503. However, the X1 output shaft 5011 and the X1 axis ball screw 502 can also be arranged at mutually offset positions and indirectly connected by a drive transmission element such as a drive belt or gear. In addition, the X1 axis can be tilted relative to the horizontal direction, and the Y1 axis can be tilted relative to the vertical direction. Furthermore, the X1 axis can be vertical, and the Y1 axis can be horizontal.

[0075] Furthermore, the constituent elements contained individually in each of the variations described above can also be applied to other variations.

[0076] [Explanation of Symbols]

[0077] 1 NC Lathe

[0078] 5. Tool Holder (First Tool Holder)

[0079] 31 First spindle (main spindle)

[0080] 502 X1 axis ball screw (drive shaft)

[0081] 504 X1 shaft support bearing (movement restriction part)

[0082] 512 X1 axis ball screw nut (driven part)

[0083] CL1 First spindle centerline (spindle centerline)

[0084] T1 tools

[0085] W1 is the workpiece.

Claims

1. A lathe, characterized in that, have: The spindle holds the workpiece and can rotate about the spindle centerline. A tool holder, equipped with a tool that processes the workpiece by cutting into it and holding it in place by the spindle; A drive shaft extends in an axis orthogonal to the center line of the main shaft, causing the tool holder to move in that axis; and A movement limiting part is disposed at one end of the drive shaft along the axial direction, thereby limiting the movement of the drive shaft along that axial direction; and The tool holder has a driven part that engages with the drive shaft and moves along the axial direction by rotation of the drive shaft; and The cutting direction of the tool is the direction in which the driven part moves towards the movement limiting part; and The orthographic projection of the tool's tip onto the drive shaft partially coincides with the driven portion.

2. The lathe according to claim 1, characterized in that, The driven part is disposed on the cutting direction side portion of the tool holder.

3. The lathe according to claim 1 or 2, characterized in that, It is equipped with a motor that rotates the drive shaft; The motor is positioned closer to the cutting direction side than the tool holder.

4. The lathe according to claim 1 or 2, characterized in that, It is equipped with a motor that rotates the drive shaft; The tool post is positioned closer to the back side of the lathe than the spindle centerline; The motor is positioned closer to the front side of the lathe than the tool post.

5. The lathe according to claim 1 or 2, characterized in that, It is equipped with a motor that rotates the drive shaft; The tool post is positioned closer to the front side of the lathe than the spindle centerline; The motor is positioned closer to the back side of the lathe than the tool post.

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