Spindle device

Abstract

To provide a spindle device having simple structure.SOLUTION: A spindle device 10 comprises: a frame 11; a feed carriage 17 supported by the frame 11 movably back and forth; a spindle 29 which is rotatably supported by the feed carriage 17 and has a spindle bore 29a to which a tool 3 is fitted and a spline hole 29b which is arranged at a proximal end part of the spindle 29; a drawbar 31 which is arranged in the spindle 29; a collet 33 which is arranged in the drawbar 31; an elastic body 32 which energizes the drawbar 31 in a direction toward the proximal end of the spindle 29; and a spline shaft 23 which is inserted into the spline hole 29b, is rotatably supported by the frame 11 and comes in contact with the drawbar 31 when the feed carriage 17 moves in the direction toward the proximal end and causes the collet 33 to release the tool 3 when the feed carriage 17 moves in the direction toward the proximal end.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A drilling machine has been proposed that has a frame having a linear guide support plate with a reference surface, a ram support plate with a ram guide hole, and a motor support part, a linear guide arranged on the reference surface, a slider that reciprocates along the linear guide, a ram arranged on the slider and passing through the ram guide hole, a main shaft journaled within the ram, a main shaft motor connected to the main shaft, a nut arranged on the slider, a feed screw having a screw shaft one end journaled on the motor support part and the other end a free end, and a feed motor connected to the screw shaft (Patent Publication No. 2022-71706). Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide a spindle device with a simple structure. [Means for solving the problem]

[0004] A first aspect of the present invention is The frame and a hollow slide table supported by the frame so as to be able to move forward and backward; a hollow main shaft rotatably supported on the slide about a rotation axis, a spindle hole disposed at a tip end of the spindle and capable of receiving a tool; a spline hole disposed at a base end of the main shaft and extending along the rotation shaft; a main shaft having a a draw bar disposed at a tip end of the spindle so as to be reciprocable relative to the spindle; a collet disposed on the draw bar that secures the tool in the spindle bore when the draw bar moves proximally relative to the spindle; an elastic body disposed inside the main shaft and biasing the draw bar toward the base end of the main shaft; a splined shaft extending along the rotation axis, inserted into the splined hole, and rotatably supported by the frame, the splined shaft abutting against the draw bar when the slide table moves in the base end direction, and supporting the draw bar against the elastic force of the elastic body when the slide table moves in the base end direction, so that the collet releases the tool; The spindle device has the following features.

[0005] The slide may be a ram. The frame may be a spindle head fed in the direction of the axis of rotation. The main shaft motor rotates the spline shaft, and the rotation of the spline shaft is transmitted to the main shaft through the spline hole.

[0006] The draw bar may pull the pull stud of the tool toward the base end of the spindle by the elastic force of the elastic body. The draw bar may pull the collet by the elastic force of the elastic body, bringing the inner surface of the tool into close contact with the spindle hole. The elastic body is, for example, a disc spring or a compression coil spring. Both ends of the feed screw shaft may be supported by a frame. The spindle device may have a support block that is arranged to be able to reciprocate on a linear guide and that supports the slide.

[0007] The feeding device is a feed motor disposed on the frame; a feed screw shaft connected to the feed motor, extending parallel to the rotation shaft, and rotatably supported by the frame; a feed nut attached to the feed screw shaft and disposed on the feed table; It may have:

[0008] When the spindle releases the tool, the feed device pulls the slide toward the base end of the spindle. When the feed device moves the slide near the base end of the slide's stroke, the tip of the splined shaft (spline head) comes into contact with the draw bar. The splined shaft does not move axially. When the feed device pulls the slide further, the splined shaft pushes the draw bar toward the tip of the spindle relative to the spindle. The collet then releases the tool. When the feed device then pulls the slide further, the draw bar or collet pushes the tool out, releasing it from the spindle bore. The released tool is then received by an automatic tool changer or an operator.

[0009] When a tool is attached, the automatic tool changer or the operator inserts the tool into the spindle hole. Next, the feed device moves the slide toward the tip of the spindle. Immediately after the movement starts, the collet holds the tool. Next, the draw bar moves toward the base end of the spindle relative to the spindle. Then, the elastic force of the elastic body moving toward the base end of the spindle is gradually applied to the draw bar. The draw bar then fixes the tool to the spindle via the collet.

[0010] The tool includes a tooling tool. The tooling tool may have, for example, a tapered shank, a bottle grip taper, and a hollow taper. The hollow taper may be, for example, a shrink fit chuck. The collet may bias the pull stud in a proximal direction to mount the tool in the tool hole. The collet may bias the inner surface of the hollow taper radially outward to mount the tool in the tool hole. [Effects of the Invention]

[0011] According to the present invention, a spindle device with a simple structure can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] Cross-sectional view of a punching machine according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1, the spindle unit 10 of this embodiment has a frame 11, a spline shaft 23, a ram (slide table) 17, a main bearing 19, a spindle 29, a draw bar 31, a plurality of disc springs (elastic bodies) 32, and a collet 33. The spindle unit 10 may also have a spindle motor 47, a linear guide 13, a support block 15, a bearing 24, and a feed device 34. The feed device 34 includes a feed motor 41 , a ball screw (feed screw) 35 , a bearing 37 , a driving pulley 43 , a driven pulley 39 , and a drive belt 45 .

[0014] 1 is a cross-sectional view taken along a plane passing through the rotation axis 1 of the spindle 29 and the central axis of the ball screw 35. In FIG. 1, the part above the rotation axis 1 shows a state in which a tool 3 is attached to the spindle 29. In FIG. 1, the part below the rotation axis 1 shows a state in which the tool 3 is detached from the spindle 29.

[0015] The spindle device 10 is incorporated into, for example, a drilling machine (not shown), a boring machine (not shown), or a machining center (not shown). The drilling machine includes a spindle unit 10 and a table (not shown). The table may be connected to a frame 11. The drilling machine may further include a robot (not shown). For example, a table and a robot may be placed on the floor. The spindle unit 10 may be placed at the end of the robot's arm. In this case, the robot can freely position the spindle unit 10 so that it faces a workpiece placed on the table. The machining center has a spindle unit 10, a table (not shown), and a moving device (not shown). The moving device moves the spindle unit 10 in the left-right and up-down directions facing the table.

[0016] The frame 11 is a hollow box. The frame 11 has a ram support hole 11a and a motor support plate 11b. The linear guide 13 is disposed in the frame 11. The support block 15 is disposed in the linear guide 13 and reciprocates along the rotation shaft 1.

[0017] The ram 17 is disposed in the support block 15 and passes through the ram support hole 11a. The ram 17 slides in the ram support hole 11a. The ram 17 has a hollow structure. The ram 17 extends along the rotation axis 1.

[0018] The main shaft 29 is supported inside the ram 17 via the main bearing 19. The main shaft 29 has a hollow structure. Inside the main shaft 29, in order from the tip, there is a main shaft hole 29a, a collet chamber 29e, a spring chamber 29d, a support hole 29c, and a spline hole 29b. The main shaft hole 29a, the collet chamber 29e, the spring chamber 29d, the support hole 29c, and the spline hole 29b are connected to one another. The support hole 29c is located in the center of the main shaft 29. The spline hole 29b is located at the base end of the main shaft 29.

[0019] The tool 3 has a pull stud 3a. The tool 3 is attached to the spindle hole 29a. Cutting oil is supplied to the tool 3. The cutting oil is supplied by an external oil supply system or an internal oil supply system. The internal oil supply system includes a center-through system and a side-through system. A known method of supplying cutting oil is disclosed in, for example, Patent No. 5469490.

[0020] The draw bar 31 is disposed so as to pass through the collet chamber 29e and the spring chamber 29d. The draw bar 31 reciprocates along the rotation shaft 1. Collet 33 is connected to the tip of draw bar 31 and is disposed in collet chamber 29e. As shown above rotary shaft 1 in FIG. 1, when collet 33 is pulled by draw bar 31 in the proximal direction relative to spindle 29, it grips pull stud 3a. Disc spring 32 is disposed in spring chamber 29d and presses draw bar 31 toward the base end of spindle 29. By pulling draw bar 31 toward the base end, disc spring 32 fixes tool 3 gripped by collet 33 in spindle hole 29a.

[0021] The spline shaft 23 has a spline head 23a. The spline shaft 23 is supported on the motor support plate 11b via a bearing 24. The spline shaft 23 is inserted into the spline hole 29b. The outer diameter of the spline head 23a is substantially the same as or larger than the outer diameter of the spline shaft 23. The outer diameter of the spline head 23a is substantially equal to the outer diameter of the support hole 29c. 1, when the ram 17 moves toward the base end, the spline head 23a is supported by the support hole 29c. At this time, the outer diameter of the spline head 23a slides in the support hole 29c.

[0022] The main shaft motor 47 is directly connected to the spline shaft 23. The main shaft motor 47 may be connected to the spline shaft 23 via a timing belt mechanism, a gear mechanism, a reducer, or a coupling. The main shaft motor 47 rotates the main shaft 29 via the spline shaft 23.

[0023] The feed motor 41 is disposed on the motor support plate 11b. The ball screw 35 has a screw shaft 35b and a nut 35a. The screw shaft 35b extends parallel to the rotation axis 1. Both ends of the screw shaft 35b are supported by the frame 11 via bearings 37. The nut 35a is disposed on the support block 15. The driving pulley 43 is fastened to the output shaft of the feed motor 41. The driven pulley 39 is fastened to the screw shaft 35b. The drive belt 45 is stretched between the driving pulley 43 and the driven pulley 39. The drive belt 45 is, for example, an endless toothed belt. The feed motor 41 may be directly connected to the screw shaft 35b, or may be connected to the screw shaft 35b via a gear mechanism, a reducer, or a coupling.

[0024] The tool replacement method will now be described. When the ram 17 moves near the base end of its stroke, the spline head 23a is inserted into the support hole 29c. As the ram 17 moves further in the base direction, the spline head 23a abuts against the base end of the draw bar 31. Even if the ram 17 moves further in the base direction, the position of the draw bar 31 is maintained because it is in contact with the spline shaft 23. The spindle 29 moves in the base direction together with the ram 17. As a result, the spline head 23a pushes the draw bar 31 toward the tip relative to the spindle 29. This opens the collet 33. As shown below the rotating shaft 1 in FIG. 1, when the ram 17 reaches near the end of its stroke in the base direction, the spindle 29 moves downward in the base direction relative to the position of the tool 3. Then, the tool 3 is removed from the spindle hole 29a. The tool 3 is removed by an operator or an automatic tool changer.

[0025] Next, another tool 3 is inserted into the spindle hole 29a by an operator or an automatic tool changer. Next, the ram 17 moves toward the tip. As a result, the collet 33 grips the ram 17. As the ram 17 moves further toward the tip, as shown above the rotary shaft 1 in FIG. 1, the draw bar 31 retracts the collet 33. As a result, the collet 33 fixes the tool 3 in the spindle hole 29a.

[0026] A typical prior art (for example, Japanese Utility Model Laid-Open Publication No. 60-48927) requires a push rod for pushing out the draw bar and a drive device for the push rod.

[0027] According to the spindle unit 10 of this embodiment, the feed device 34 moves the ram 17 in the base end direction, causing the draw bar 31 to abut against the spline shaft 23. Then, the spline shaft 23 pushes the draw bar 31 out relative to the spindle 29. Then, the collet 33 releases the tool 3. In this way, the spindle unit 10 can unclamp or clamp the tool 3 with a very simple operation. The spindle unit 10 does not require a push rod or a drive unit. The spindle unit 10 can drive the draw bar 31 by the feed device 34, which moves the ram 17, and the spline shaft 23, which rotates the spindle 29.

[0028] The size of the spindle bore 29a and the elastic force of the disc spring 32 are designed based on the magnitude of the machining reaction force and vibrations that the tool 3 receives. As the size of the spindle bore 29a increases, the elastic force of the disc spring 32 must also increase. In conventional technology, the push rod drive mechanism must push the push rod and draw bar 31 toward the tip against the elastic force of the disc spring. Therefore, as the size of the spindle bore 29a increases, the drive mechanism also becomes larger and its mass increases. Hydraulic devices or servo devices are often selected as the drive mechanism.

[0029] The spindle unit 10 of this embodiment does not require a push rod, a drive unit for the push rod, or a device for fixing them. Furthermore, the feed unit 34 can exert a force to push out the ram 17 against the machining reaction force of the tool 3. Therefore, even if the size of the tool 3 or the spindle hole 29a increases, the feed unit 34 can drive the draw bar 31. The spindle unit 10 of this embodiment can be made smaller. Furthermore, the mass of the spindle unit 10 can be reduced.

[0030] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention, and all technical matters included in the technical ideas described in the claims are subject to the present invention. The above-described embodiments are preferred examples, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the appended claims. [Explanation of symbols]

[0031] 3 tools 10 Spindle device 17 Ram (feed table) 23 Spline shaft 29 Main shaft 31 Drawbar 32 Disc spring (elastic body) 33 Colette

Claims

1. The frame and a hollow slide table supported by the frame so as to be able to move forward and backward; a hollow main shaft rotatably supported on the slide about a rotation axis, a spindle hole disposed at a tip end of the spindle and capable of receiving a tool; a spline hole disposed at a base end of the main shaft and extending along the rotation shaft; a main shaft having a a draw bar disposed at a tip end of the spindle so as to be reciprocable relative to the spindle; a collet disposed on the draw bar that secures the tool in the spindle bore when the draw bar moves proximally relative to the spindle; an elastic body disposed inside the main shaft and biasing the draw bar toward the base end of the main shaft; a splined shaft extending along the rotation axis, inserted into the splined hole, and rotatably supported by the frame, the splined shaft abutting against the draw bar when the slide table moves in the base end direction, and supporting the draw bar against the elastic force of the elastic body when the slide table moves in the base end direction, so that the collet releases the tool; A spindle device having

2. the spline hole is connected to the spindle hole; The spindle device according to claim 1 .

3. the spline shaft has a spline head disposed at a tip end of the spline shaft and abutting against the draw bar; The spindle device according to claim 1 or 2.

4. the main shaft is disposed on the base end side of the draw bar and has a support hole that supports the spline head when the main shaft moves in the base end direction; The spindle device according to any one of claims 1 to 3.

5. a main shaft motor disposed on the frame and connected to the spline shaft; The spindle device according to any one of claims 1 to 4.

6. a linear guide disposed on the frame and extending along the rotation axis; a feed device disposed on the frame and adapted to reciprocate the slide; The spindle device according to any one of claims 1 to 5, further comprising:

7. The frame has a slide passage hole extending along the rotation axis, The slide passes through the slide passage hole. The spindle device according to any one of claims 1 to 6.

Images