JP6769030B2 - Spindle equipment and machine tools - Google Patents

Description

The present invention relates to a spindle device for holding a tool and a machine tool.

The machine tool is provided with a spindle device, which is provided at a spindle, one end of the spindle, a chuck mechanism for gripping a tool, a drawbar connected to the chuck mechanism, and around the drawbar. A spring is provided on the other end side of the spindle to urge the drawbar (see, for example, Patent Document 1).

When the drawbar is located on the other end side of the spindle, the chuck mechanism grips the tool. When the drawbar moves toward one end of the spindle against the urging force of the spring, the chuck mechanism releases the grip of the tool.

Japanese Unexamined Patent Publication No. 2008-137110

When the drawbar moves toward one end of the spindle, the spring is shortened and the axially central portion of the spring expands radially outward, so that a gap is created between the drawbar and the spring. When the drawbar is gripping the tool, the spring is not fully extended. Therefore, there is a gap between the drawbar and the spring. When the spindle rotates at high speed while holding the tool, the spring vibrates due to the gap. The vibration of the spring is transmitted to the spindle, which reduces the machining accuracy of the workpiece.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a spindle device and a machine tool for suppressing vibration of a spring provided around a drawbar.

The spindle device according to the present invention is located around a tubular spindle that can rotate around an axis on which a tool is mounted at one end, a drawbar that can move in the axial direction inside the spindle, and a drawbar. In a spindle device including a spring that urges the drawbar to the other end side of the spindle, the spring has a small diameter portion whose inner diameter is smaller than other portions, or the drawbar has another diameter. It is characterized by having a large-diameter portion larger than the portion of.

The spindle device according to the present invention is characterized in that at least a part of the small diameter portion or the large diameter portion is located at the center of the spring in the axial direction.

The spindle device according to the present invention is characterized in that the spring includes a coil spring.

The spindle device according to the present invention is characterized by having a step at the boundary between the small diameter portion and the other portion.

The spindle device according to the present invention is characterized in that the other portion has a frustum-shaped portion whose outer diameter on the small diameter portion side is smaller than that on the opposite side of the small diameter portion.

The machine tool according to the present invention is characterized by including any of the above-mentioned spindle devices.

In the present invention, the spring has a small diameter portion or the drawbar has a large diameter portion, so that when the spring is shortened, a gap is suppressed between the spring and the drawbar.

In the present invention, the occurrence of the gap is surely suppressed by locating the small diameter portion or the large diameter portion in the axial center of the spring where the gap is most likely to occur.

In the present invention, by using a coil spring, it is possible to reduce the manufacturing cost as compared with the case of using a disc spring or the like.

In the present invention, by manufacturing the spring in a stepped shape, centering is facilitated and the accuracy of the spring is improved when manufacturing a small diameter portion and other portions having different inner diameters.

In the present invention, when the drawbar is inserted into the spring, a frustum-shaped portion guides the drawbar.

In the spindle device and machine tool according to the present invention, a gap is generated between the spring and the drawbar when the spring is shortened due to the spring having a small diameter portion or the drawbar having a large diameter portion. Can be prevented and the vibration of the spring can be suppressed.

It is a perspective view which shows the machine tool which concerns on Embodiment 1. It is sectional drawing which shows schematic the spindle device. It is sectional drawing which shows schematic the draw bar and the coil spring. It is sectional drawing which shows the draw bar and the coil spring of the machine tool which concerns on the modification 1 which partially changed the structure of the coil spring. It is sectional drawing which shows the draw bar and the coil spring of the machine tool which concerns on the modification 2 which partially changed the structure of the coil spring. It is sectional drawing which shows the draw bar and the coil spring of the machine tool which concerns on Embodiment 2.

(Embodiment 1)
Hereinafter, the present invention will be described with reference to the drawings showing the machine tool according to the first embodiment. In the following description, up and down, left and right, and front and back indicated by arrows are used in the figure. FIG. 1 is a perspective view illustrating a machine tool.

The machine tool 100 includes a rectangular base 1 extending back and forth. A work holding portion 3 for holding the work is provided on the front side of the upper part of the base 1. The work holding portion 3 can rotate around the A-axis with the left-right direction as the axial direction and the C-axis with the vertical direction as the axial direction.

A support base 2 for supporting the column 4 described later is provided on the rear side of the upper part of the base 1. A Y-axis direction moving mechanism 10 for moving the moving plate 16 in the front-rear direction is provided on the upper portion of the support base 2. The Y-axis direction moving mechanism 10 includes two rails 11 extending in the front-rear direction, a Y-axis screw shaft 12, a Y-axis motor 13, and a bearing 14.

Rails 11 are provided on the left and right sides of the upper part of the support base 2. The Y-axis screw shaft 12 extends back and forth and is provided between the two rails 11. Bearings 14 are provided at the front end and the middle of the Y-axis screw shaft 12. The bearing provided in the middle part is not shown. The Y-axis motor 13 is connected to the rear end of the Y-axis screw shaft 12.

A nut (not shown) is screwed to the Y-axis screw shaft 12 via a rolling element (not shown). The rolling element is, for example, a ball. A plurality of sliders 15 are slidably provided on each rail 11. A moving plate 16 is connected to the upper part of the nut and the slider 15. The moving plate 16 extends in the horizontal direction. The rotation of the Y-axis motor 13 causes the Y-axis screw shaft 12 to rotate, the nut to move in the front-rear direction, and the moving plate 16 to move in the front-back direction.

An X-axis direction moving mechanism 20 for moving the column 4 in the left-right direction is provided on the upper surface of the moving plate 16. The X-axis direction moving mechanism 20 includes two rails 21 extending to the left and right, an X-axis screw shaft 22, an X-axis motor (not shown), and a bearing 23.

Rails 21 are provided on the front and rear surfaces of the upper surface of the moving plate 16. The X-axis screw shaft 22 extends to the left and right and is provided between the two rails 21. Bearings 23 are provided at the left end and the middle of the X-axis screw shaft 22. The description of the bearing provided in the middle of the X-axis screw shaft 22 is omitted. The X-axis motor is connected to the right end of the X-axis screw shaft 22.

A nut (not shown) is screwed to the X-axis screw shaft 22 via a rolling element (not shown). Grease is applied to the X-axis screw shaft 22. A plurality of sliders 26 are slidably provided on each rail 21. A column 4 is connected to the upper part of the nut and the slider 26. Column 4 has a columnar shape. The rotation of the X-axis motor causes the X-axis screw shaft 22 to rotate, the nut to move in the left-right direction, and the column 4 to move in the left-right direction.

A Z-axis direction moving mechanism 30 for moving the spindle head 5 in the vertical direction is provided on the front surface of the column 4. The Z-axis direction moving mechanism 30 includes two rails 31 extending vertically, a Z-axis screw shaft 32, a Z-axis motor 33, and a bearing 34.

Rails 31 are provided on the left and right sides of the front surface of the column 4. The Z-axis screw shaft 32 extends vertically and is provided between the two rails 31. Bearings 34 are provided at the lower end and the middle portion of the Z-axis screw shaft 32, respectively. The bearing provided in the middle part is not shown. The Z-axis motor 33 is connected to the upper end of the Z-axis screw shaft 32.

A nut (not shown) is screwed to the Z-axis screw shaft 32 via a rolling element (not shown). Grease is applied to the Z-axis screw shaft 32. A plurality of sliders 35 are slidably provided on each rail 31. The spindle head 5 is connected to the front portion of the nut and the slider 35. The rotation of the Z-axis motor 33 causes the Z-axis screw shaft 32 to rotate, the nut to move in the vertical direction, and the spindle head 5 to move in the vertical direction. The Z-axis motor 33, the Z-axis screw shaft 32, the nut, and the rolling element form a ball screw mechanism.

The spindle device 50 is provided on the spindle head 5. The spindle device 50 has a spindle 51 extending vertically. The spindle 51 rotates about an axis. A spindle motor 6 is provided at the upper end of the spindle head 5. A tool is attached to the lower end of the spindle 51. The rotation of the spindle motor 6 causes the spindle 51 to rotate, and the tool to rotate. The rotated tool processes the work held by the work holding portion 3.

The machine tool 100 includes a tool changing device (not shown) for changing tools. The tool changing device replaces the tool housed in the tool magazine (not shown) with the tool mounted on the spindle 51.

FIG. 2 is a cross-sectional view illustrating the spindle device 50. The spindle device 50 includes a tubular spindle 51, a chuck mechanism 52 for holding a tool, a draw bar 53, and a coil spring 54. A partition wall 51c is provided inside the main shaft 51. The first chamber 51a is provided on the upper side of the partition wall 51c, and the second chamber 51b is provided on the lower side of the partition wall 51c.

A draw bar 53 is inserted into the main shaft 51 along the axial direction. The drawbar 53 is movable in the axial direction. A rod-shaped main body portion 53a, a connecting shaft portion 53b, a flange portion 53c, and a screw shaft portion 53d are provided. The connecting shaft portion 53b projects axially from one end of the main body portion 53a and is connected to the chuck mechanism 52. The flange portion 53c has a larger diameter than the main body portion 53a and the connecting shaft portion 53b, and is provided at the connecting portion of the connecting shaft portion 53b and the main body portion 53a. The screw shaft portion 53d is provided at the other end of the main body portion 53a.

The main body portion 53a and the flange portion 53c are located in the first chamber 51a. The connecting shaft portion 53b penetrates the partition wall 51c and is located in the first chamber 51a and the second chamber 51b. The chuck mechanism 52 is provided at the end of the second chamber 51b. The connecting shaft portion 53b is connected to the chuck mechanism 52.

A spring receiver 59 is provided around the flange portion 53c. The spring receiver 59 is located in the first chamber 51a. The spring receiver 59 includes a tubular portion 59a and an annular portion 59b. The annular portion 59b is coaxially provided at the end of the tubular portion 59a. The diameter of the opening of the annular portion 59b is smaller than the diameter of the flange portion 53c. The main body portion 53a is inserted into the opening of the annular portion 59b from the tubular portion 59a side.

An extension member 57 is provided at the upper end of the first chamber 51a. The screw shaft 53d is screwed and connected to the extension member 57. In the first chamber 51a, a coil spring 54 is provided around the main body 53a. The coil spring 54 is located between the extension member 57 and the spring receiver 59, and the upper and lower ends of the coil spring 54 come into contact with the extension member 57 and the spring receiver 59, respectively. The coil spring 54 urges the extension member 57 and the drawbar 53 upward.

A plurality of bearings 55 are fitted on the outside of the lower part of the spindle 51 to rotatably support the spindle 51 around the axis. The non-mounting cylinder 56 is fitted on the outside of the upper part of the spindle 51. A flange 56a is provided at the lower end of the non-mounting cylinder 56. The non-mounting cylinder 56 is located on the radial outer side of the extension member 57.

Two oval holes (not shown) extending in the axial direction are provided on the upper part of the main shaft 51. The two oval holes face each other in the radial direction. The extension member 57 is provided with a pin hole 57a penetrating in the radial direction. The pin hole 57a is located at a position corresponding to the oval hole. The pin 58 is inserted into the oval hole and the pin hole 57a, and both ends of the pin 58 are connected to the non-mounting cylinder 56.

The spindle device 50 includes an arm (not shown) that pushes the non-mounting cylinder 56 downward. When the arm pushes the flange 56a downward, the drawbar 53 moves downward against the urging force of the coil spring 54.

A chuck mechanism 52 is provided at the lower end of the spindle 51. When replacing the tool mounted on the chuck mechanism 52, the spindle head 5 rises to the replacement position, the drawbar 53 lowers when the arm pushes the flange 56a downward, the coil spring 54 shortens, and the chuck mechanism 52 shortens. Release the holding of the tool. The tool changer exchanges the released tool with the new tool, the arm releases the push-down of the flange 56a, the drawbar 53 is moved upward by the coil spring 54, and the chuck mechanism 52 holds the new tool. When the chuck mechanism 52 holds the tool, the coil spring 54 is not fully extended and is still kept in a shortened state (a state in which it is extended compared to when the holding of the tool is released).

FIG. 3 is a cross-sectional view illustrating the draw bar 53 and the coil spring 54. The coil spring 54 includes an upper end portion 54a, a lower end portion 54b, and a small diameter portion 54c. The small diameter portion 54c is located between the upper end portion 54a and the lower end portion 54b, and at least a part of the small diameter portion 54c is located at the axial center of the coil spring 54.

The inner diameters of the upper end portion 54a and the lower end portion 54b are substantially constant. The inner diameter of the small diameter portion 54c is smaller than the inner diameters of the upper end portion 54a and the lower end portion 54b, and is substantially constant. That is, a step 54s is provided at the boundary between the upper end portion 54a and the lower end portion 54b and the small diameter portion 54c, respectively. The inner diameters of the upper end portion 54a and the lower end portion 54b may be different as long as they are larger than the inner diameter of the small diameter portion 54c. For example, the inner diameter of the upper end portion 54a may be larger or smaller than that of the lower end portion 54b.

As described above, when the chuck mechanism 52 holds the tool, the coil spring 54 is not fully extended and keeps the shortened state. In the spindle device 50 and the machine tool 100 according to the first embodiment, when the coil spring 54 has a small diameter portion 54c and the coil spring 54 is shortened, a gap is formed between the coil spring 54 and the drawbar 53. It suppresses the occurrence and suppresses the vibration of the coil spring 54 when the spindle 51 rotates.

The upper and lower ends of the coil spring 54 are in contact with the extension member 57 and the spring receiver 59, respectively, and are difficult to expand in the radial direction when the spindle 51 rotates. Therefore, the axially central portion of the coil spring 54 is more likely to expand in the radial direction than the upper and lower end portions, and a gap is most likely to be generated between the coil spring 54 and the drawbar 53. Since the small diameter portion 54c is located at the center of the coil spring 54 in the axial direction, the occurrence of a gap can be reliably suppressed.

Further, by using the coil spring 54, the manufacturing cost can be reduced as compared with the case of using a disc spring or the like.

Further, by manufacturing the coil spring 54 in a stepped shape, when manufacturing the small diameter portion 54c having different inner diameters and the upper end portion 54a and the lower end portion 54b, centering becomes easy and the accuracy of the coil spring 54 is improved.

The inner diameter of one of the upper end portion 54a or the lower end portion 54b may be larger than that of the small diameter portion 54c, and the inner diameter of the other may be the same as that of the small diameter portion 54c.

FIG. 4 is a cross-sectional view illustrating the draw bar 53 and the coil spring 54 of the machine tool 100 according to the first modification in which the configuration of the coil spring 54 is partially modified. The upper end portion 54d of the coil spring 54 has a frustum shape in which the inner diameter of the upper side is larger than that of the lower side. The lower end portion 54e of the coil spring 54 has a frustum shape in which the inner diameter on the lower side is larger than that on the upper side. The upper end portion 54d and the lower end portion 54e form a frustum-shaped portion.

Since the upper end portion 54d and the lower end portion 54e form a frustum shape, when the draw bar 53 is inserted into the coil spring 54, the upper end portion 54d and the lower end portion 54e guide the draw bar 53. One of the upper end portion 54d or the lower end portion 54e may have a frustum shape, and the inner diameter of the other portion may be constant.

FIG. 5 is a cross-sectional view illustrating the draw bar 53 and the coil spring 54 of the machine tool 100 according to the second modification in which the configuration of the coil spring 54 is partially modified. Two protruding portions 54f protruding in the radial direction are provided in the middle portion of the small diameter portion 54c. The inner diameter of the protruding portion 54f is larger than that of the small diameter portion 54c. At least a part of the small diameter portion 54c is located at the center of the coil spring 54 in the axial direction. In addition, three or more protrusions 54f may be provided.

(Embodiment 2)
Hereinafter, the present invention will be described with reference to the drawings showing the machine tool 100 according to the second embodiment. FIG. 6 is a cross-sectional view illustrating the draw bar 53 and the coil spring 54.

The inner diameter of the coil spring 54 is substantially constant from the upper end to the lower end. The drawbar 53 includes a large diameter portion 53e having a diameter larger than that of other portions. The draw bar 53 is inserted into the coil spring 54, and at least a part of the large diameter portion 53e is located at the center of the coil spring 54 in the axial direction.

In the spindle device 50 and the machine tool 100 according to the second embodiment, when the coil spring 54 is shortened due to the draw bar 53 having the large diameter portion 53e, there is a gap between the coil spring 54 and the draw bar 53. It can be suppressed from occurring.

Further, by locating the large diameter portion 53e at the center in the axial direction of the coil spring 54 where the gap is most likely to occur, the generation of the gap can be reliably suppressed.

Of the machine tool configurations according to the second embodiment, the same configurations as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The coil spring 54 is an example of a spring, and is not limited thereto. For example, a plurality of disc springs may be arranged vertically around the draw bar 53.
In the machine tool 100, the column 4 moves in the X direction and the Y direction, but a machine tool in which the column 4 is fixed to the support base 2 and the table holding the work is moved in the X direction and the Y direction may be used. Further, although the machine tool 100 is a vertical type in which the spindle head 5 moves up and down, a horizontal type machine tool in which the spindle head 5 moves in the front-rear direction may also be used.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The technical features described in each example can be combined with each other and the scope of the invention is intended to include all modifications within the claims and scope equivalent to the claims. Will be done.

50 Spindle device 51 Spindle 52 Chuck mechanism 53 Drawbar 53e Large diameter part 54 Coil spring (spring)
54c Small diameter part 54d Upper end part (frustum-shaped part)
54e Lower end (frustum)
54s step 100 machine tool

Claims (3)

A tubular spindle that can rotate around an axis on which a tool is mounted at one end, a drawbar that can move in the axial direction inside the spindle, and a drawbar that is located around the drawbar and has the drawbar in addition to the spindle. In a spindle device having a spring urging on the end side,
The spring has a small diameter portion having an inner diameter smaller than that of other portions.
At least a part of the small diameter portion is located at the axial center of the spring.
The spring is a coil spring and
A member arranged on the other end side of the spindle inside the spindle, connected to the drawbar, and movable in the axial direction of the spindle.
It is provided with a spring receiver which is arranged on the one end side of the spindle inside the spindle and has an opening for inserting the drawbar.
The spring is arranged between the member and the spring receiver around the rod-shaped main body of the drawbar extending from the member toward the one end side, and comes into contact with the member and the spring receiver.
When the tool is attached, the spring shortens,
When the spindle to which the tool is mounted rotates, the shortened spring rotates integrally with the spindle and the drawbar.
No groove is formed on the outer peripheral surface of the main body ,
The inner diameter of at least two turns in the small diameter portion is set to be constant.
A spindle device characterized in that the inner diameter of the other portion of the spring is set to be constant. The spindle device according to claim 1, wherein a step is provided at the boundary between the small diameter portion and the other portion. A machine tool comprising the spindle device according to claim 1 or 2 .

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