Additional shaft attachment structure

Abstract

The present invention provides an additional shaft attachment structure that makes it possible to easily perform an attachment operation after maintenance of an additional shaft, that has excellent versatility, and that makes it possible to attach an additional shaft with good precision.　An additional shaft attachment structure (1) according to the present disclosure comprises a base member (6) which links a rotation shaft case (3) that has an additional shaft (2) and an additional shaft installation part (5) of a machine tool (4). The base member (6) has a first base member (9) which is removably attached to the rotation shaft case (3) and an second base member (10) which is removably attached to the additional shaft installation part (5). The first base member (9) and the second base member (10) are positioned by engagement parts (23) that engage with each other.

Description

Additional shaft mounting structure

[0001] The present disclosure relates to an additional axis mounting structure for mounting an additional axis to a machine tool.

[0002] Conventionally, machine tools such as machining centers are provided with one or more additional axes. For example, the additional axes are attached to the table (one example of an additional axis installation unit) of the machine tool so that the rotation axis of the additional axis is aligned with the Z axis of the machine tool. In this case, the additional axis is arranged so that its axial direction is perpendicular to the table of the machine tool. Therefore, the lower end of the additional axis in the axial direction is in close proximity to the upper surface of the table of the machine tool.

[0003] Various configurations are used to attach the additional shaft to the table of the machine tool. For example, a configuration in which a flange is provided on the additional shaft is available. In the configuration in which a flange is provided on the additional shaft, the additional shaft is detachably attached to the table of the machine tool via the flange.

[0004] JP 2011-11312 A

[0005] In conventional systems, the lower end of the additional axis in the axial direction is located very close to the top surface of the machine tool table, so when performing maintenance on the lower end of the additional axis, it is necessary to remove the additional axis from the machine tool table. With conventional configurations, once the additional axis is removed from the machine tool table, it is difficult to reinstall the additional axis in its original position. For this reason, positioning parts that indicate the position of the additional axis relative to the machine tool table are sometimes used. However, using positioning parts when installing the additional axis on the machine tool table increases the number of parts, making installation of the additional axis more time-consuming. Furthermore, there are cases where it is not possible to use positioning parts due to the limited space available on the machine tool table.

[0006] In conventional cases, a plate-shaped shim may be sandwiched between the table of the machine tool and the additional axis to adjust the accuracy of the attitude of the additional axis. When a shim is placed between the table of the machine tool and the additional axis, removing the additional axis from the table of the machine tool also removes the shim from between the table of the machine tool and the additional axis. When the additional axis is removed from the table of the machine tool and then attached to its original position on the table of the machine tool, the shim is sandwiched between the table of the machine tool and the additional axis. If the shim is re-inserted in this way, there is a risk that the accuracy of the attitude of the additional axis will decrease.

[0007] In conventional cases, an additional shaft may be provided with a fixing flange. If an additional shaft with a flange is to be used in a machine tool having two additional shafts, the flange of the additional shaft may get in the way and prevent the additional shaft from being used. Therefore, conventional additional shaft mounting structures lack versatility.

[0008] In order to solve the above-mentioned problems, there is a need for an additional shaft mounting structure that allows easy mounting work after maintenance of the additional shaft, is highly versatile, and allows the additional shaft to be mounted with high precision.

[0009] The additional shaft mounting structure of the present disclosure is an additional shaft mounting structure that includes a base member that connects a rotating shaft case having an additional shaft and an additional shaft installation section of a machine tool, and the base member has a first base member that is detachably attached to the rotating shaft case and a second base member that is detachably attached to the additional shaft installation section, and the first base member and the second base member are positioned by engaging sections that engage with each other.

[0010] FIG. 1 is a schematic perspective view showing an additional shaft mounting structure according to an embodiment of the present invention in use; FIG. 2 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention, viewed from above; FIG. 3 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention, viewed from below; FIG. 4 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention in use, showing a state in which the first base member is removed from the second base member; FIG. 5 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention in use, showing a state in which a rotating shaft case is in the middle of being attached to the second base member via a holding member; FIG. 6 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention in use, showing a state in which the rotating shaft case has been attached to the second base member via a holding member; FIG. 7 is a perspective view showing an additional shaft mounting structure according to an embodiment of the present invention in use, viewed from below, showing a state in which the rotating shaft case has been attached to the second base member via a holding member.

[0011] An additional shaft mounting structure according to one aspect of the present disclosure will be described below with reference to the drawings. An additional shaft mounting structure 1 according to this embodiment will be described with reference to FIGS. 1 to 3. The additional shaft mounting structure 1 includes a base member 6. The base member 6 connects a rotating shaft case 3 having an additional shaft 2 to an additional shaft installation section 5 of a machine tool 4. For ease of explanation, in FIGS. 1 to 3, the axial direction of the additional shaft 2 is defined as the up-down direction D1. Here, one of the axial directions is defined as the up-down direction D11, and the other is defined as the down-down direction D12. In FIG. 1, of two directions intersecting the up-down direction D1, one is defined as the front-rear direction D2, and the other is defined as the left-right direction D3. More specifically, the direction from the rear side to the front side of the machine tool 4 is defined as the forward direction D21, and the opposite direction is defined as the rearward direction D22. These directions are collectively defined as the front-rear direction D2. Furthermore, the leftward direction D31 and its opposite rightward direction D32 are collectively defined as the left-right direction D3. The directions of up, down, front, back, left and right used for the convenience of explanation may differ from the directions in the actual device.

[0012] The rotating shaft case 3 has a case main body 7 and an additional shaft 2. In this embodiment, the case main body 7 is shaped like a substantially rectangular box in a plan view. The additional shaft 2 is rotatably provided in this case main body 7. When the additional shaft 2 is provided in the case main body 7, the axial direction of the additional shaft 2 is along the vertical direction D1. When the additional shaft 2 is provided in the case main body 7, the additional shaft 2 penetrates the case main body 7 in the vertical direction D1. When the additional shaft 2 is provided in the case main body 7, the additional shaft 2 is rotatable around its own axis. The rotating shaft case 3 configured as described above is provided in a machine tool 4, as will be described later, with the axial direction of the additional shaft 2 along the vertical direction D1. Therefore, in this embodiment, the additional shaft 2 is a C-axis.

[0013] The machine tool 4 has an additional axis installation section 5 on which the additional axis 2 is installed. The machine tool 4 is not particularly limited, but in this embodiment it is a machining center. When the machine tool 4 is a machining center, the additional axis installation section 5 is a table of the machining center. The additional axis installation section 5 is plate-shaped, and the plate surface faces in the up-down direction D1. A plurality of grooves 8 that are open upward and recessed downward are provided on the plate surface on the upper side of the additional axis installation section 5. Each groove 8 extends in the left-right direction D3. The plurality of grooves 8 are arranged at a distance in the front-rear direction D2.

[0014] A base member 6 is used when installing the rotary shaft case 3 on the additional shaft installation section 5 of the machine tool 4. The base member 6 has a first base member 9 located on the upper side and a second base member 10 located on the lower side.

[0015] In this embodiment, the first base member 9 has a plate-like shape with a substantially rectangular outer shape in a plan view, with the plate surface facing the vertical direction D1. The first base member 9 has a shaft through hole 11 through which the additional shaft 2 provided in the rotating shaft case 3 passes. The shaft through hole 11 is provided in the center of the first base member 9. The shaft through hole 11 is circular in a plan view and passes through the first base member 9 in the vertical direction D1. The first base member 9 has base mounting holes 12 for detachably mounting the first base member 9 to the second base member 10. The base mounting holes 12 are provided at the four corners of the first base member 9. The base mounting holes 12 are circular in a plan view and pass through the first base member 9 in the vertical direction D1. The base mounting holes 12 are stepped holes and include a large-diameter hole 13 located on the upper side and a small-diameter hole 14 located on the lower side. The number of base mounting holes 12 is not limited to four.

[0016] The first base member 9 is detachably attached to the rotating shaft case 3. Therefore, in this embodiment, the first base member 9 has case mounting holes 15 for attaching the first base member 9 to the rotating shaft case 3. The case mounting holes 15 are circular in a plan view and penetrate the first base member 9 in the up-down direction D1. In the illustrated example, two case mounting holes 15 are located on the front side of the first base member 9 and two case mounting holes 15 are located on the rear side of the first base member 9. The number of case mounting holes 15 is not limited to four. The case mounting holes 15 are stepped holes and have a small diameter hole 16 located on the upper side and a large diameter hole 17 located on the lower side.

[0017] In this embodiment, the second base member 10 is a plate-like member that is generally rectangular in plan view and larger in outer shape than the first base member 9, with the plate surface facing the up-down direction D1. The second base member 10 has a storage section 18 that stores the lower end of the additional shaft 2 provided in the rotating shaft case 3. The storage section 18 is provided in the center of the second base member 10. The storage section 18 is a recessed shape with a bottom that opens upward and is circular in plan view. The second base member 10 has a base fixing hole 19 for detachably attaching the first base member 9 to the second base member 10.

[0018] The base fixing holes 19 are provided in the second base member 10 so as to correspond to the base mounting holes 12 of the first base member 9. Specifically, two base fixing holes 19 are located on the front side of the second base member 10, and two base fixing holes 19 are located on the rear side of the second base member 10. The base fixing holes 19 are threaded holes with threads formed on their inner circumferential surfaces.

[0019] The second base member 10 is detachably attached to the additional axis installation section 5 of the machine tool 4. Therefore, in this embodiment, the second base member 10 has base installation holes 21 for attaching the second base member 10 to the additional axis installation section 5. The base installation holes 21 are provided at the four corners of the second base member 10. The base installation holes 21 have a circular shape in a plan view, and penetrate the second base member 10 in the up-down direction D1. It should be noted that the number of base installation holes 21 is not limited to four.

[0020] The first base member 9 and the second base member 10 are positioned by engaging portions 22, 23 that engage with each other. Therefore, in this embodiment, a concave engaging portion 22 is provided on the first base member 9, and a convex engaging portion 23 is provided on the second base member 10. The engaging portion 22 of the first base member 9 is provided on the lower surface of the first base member 9 so as to be recessed upward. The engaging portion 22 of the first base member 9 is circular in bottom view. The engaging portion 23 of the second base member 10 is provided on the upper surface of the second base member 10 so as to protrude upward. The engaging portion 23 of the second base member 10 is cylindrical.

[0021] In the illustrated example, two engagement portions 22 are provided on the front edge portion of the first base member 9, and two engagement portions 23 are provided on the front edge portion of the second base member 10. The two engagement portions 22 are arranged spaced apart in the length direction of the front edge portion of the first base member 9. The two engagement portions 23 are arranged spaced apart in the length direction of the front edge portion of the second base member 10.

[0022] To position the first base member 9 and the second base member 10, the lower surface of the first base member 9 is brought into contact with the upper surface of the second base member 10, and the convex engaging portion 23 of the second base member 10 is inserted into the concave engaging portion 22 of the first base member 9. Here, the concave engaging portion 22 is provided on the first base member 9 and the convex engaging portion 23 is provided on the second base member 10, but the reverse configuration may also be used. That is, the first base member 9 may be provided with a convex engaging portion, and the second base member 10 may be provided with a concave engaging portion. The engaging portions 22 of the first base member 9 and the engaging portions 23 of the second base member 10 are not limited to the shapes described above.

[0023] Since this embodiment has such a configuration, the rotating shaft case 3 having the additional shaft 2 can be installed on the additional shaft installation part 5 of the machine tool 4 via the base member 6. When the rotating shaft case 3 is installed on the additional shaft installation part 5, the axial direction of the additional shaft 2 is aligned with the up-down direction D1.

[0024] Specifically, with the lower surface of the second base member 10 abutting against the upper surface of the additional axis installation section 5, the second base member 10 is attached to the additional axis installation section 5 by inserting bolts 24 through the base installation holes 21 into the grooves 8 on the upper surface of the additional axis installation section 5. The second base member 10 can be attached at any position along the grooves 8 of the additional axis installation section 5.

[0025] The first base member 9 is attached to the rotating shaft case 3 by abutting the upper surface of the first base member 9 against the lower surface of the rotating shaft case 3 and threading bolts 26 into threaded holes (not shown) of the rotating shaft case 3 via case mounting holes 15 with the additional shaft 2 passing through the shaft through hole 11. With the first base member 9 attached to the rotating shaft case 3, the lower end of the additional shaft 2 of the rotating shaft case 3 passes through the shaft through hole 11 of the first base member 9 and therefore protrudes downward from the first base member 9. In the illustrated example, the lower end of the additional shaft 2 is generally circular in bottom view.

[0026] When the first base member 9 is attached to the rotating shaft case 3, the head of the bolt 26 is housed in the large diameter hole 17 of the case mounting hole 15. Therefore, the head of the bolt 26 does not protrude downward from the first base member 9. The first base member 9 is attached to the second base member 10 by abutting the lower surface of the first base member 9 against the upper surface of the second base member 10 and inserting the engaging portion 23 of the second base member 10 into the engaging portion 22 of the first base member 9, and then screwing the bolt 27 into the base fixing hole 19 of the second base member 10 through the base mounting hole 12. Therefore, the first base member 9 is detachably attached to the second base member 10.

[0027] When the first base member 9 is attached to the second base member 10, the engaging portion 22 of the first base member 9 engages with the engaging portion 23 of the second base member 10, thereby positioning the first base member 9 relative to the second base member 10. When the first base member 9 is attached to the second base member 10, the head of the bolt 27 is housed in the large diameter hole 13 of the base mounting hole 12. Therefore, the head of the bolt 27 does not protrude upward from the first base member 9.

[0028] In this way, the rotating shaft case 3 is attached to the additional shaft installation part 5 by the base member 6. Therefore, the base member 6 can detachably connect the rotating shaft case 3 and the additional shaft installation part 5. When the rotating shaft case 3 is installed on the additional shaft installation part 5, the lower end of the additional shaft 2 is accommodated in the accommodation part 18 of the second base member 10.

[0029] Next, maintenance of the additional shaft 2 of the rotating shaft case 3 will be described using Figures 4 to 7. As described above, the rotating shaft case 3 is attached to the additional shaft installation part 5 by the base member 6. In this case, it can be said that the rotating shaft case 3 is detachably attached to the second base member 10 by the first base member 9. Here, the state in which the rotating shaft case 3 is attached to the second base member 10 by the first base member 9 is referred to as the "first state."

[0030] To perform maintenance on the additional shaft 2, first, as shown in FIG. 4 , the rotating shaft case 3 is removed from the first state. Specifically, with the first base member 9 attached to the rotating shaft case 3, the first base member 9 is removed from the second base member 10 attached to the additional shaft installation section 5. To remove the first base member 9 from the second base member 10, the bolts 27 are simply removed from the base fixing holes 19 of the second base member 10. This releases the connection between the first base member 9 and the second base member 10, making the first base member 9 removable from the second base member 10. By lifting the first base member 9 from this state, the rotating shaft case 3 to which the first base member 9 is attached can be removed from the second base member 10. Lifting the first base member 9 releases the engagement between the engagement portion 22 of the first base member 9 and the engagement portion 23 of the second base member 10. That is, by lifting up the first base member 9 , the engaging portion 23 of the second base member 10 is disengaged from the engaging portion 22 of the first base member 9 .

[0031] After the first base member 9 is removed from the second base member 10, the rotating shaft case 3 is detachably attached to the second base member 10 via the holding member 28, as shown in Figures 5 to 7. Specifically, the holding member 28 is detachably attached to the rotating shaft case 3, and the holding member 28 is detachably attached to the second base member 10 in a state where it is attached to the additional shaft installation part 5.

[0032] The holding member 28 has a generally rectangular plate shape in a plan view, with the plate surface facing the up-down direction D1. The holding member 28 has case mounting holes 29 for mounting to the rotating shaft case 3. The case mounting holes 29 have a circular shape in a plan view, and penetrate the holding member 28 in the up-down direction D1. In the illustrated example, two case mounting holes 29 are located on the front side of the holding member 28, and two case mounting holes 29 are located on the rear side of the holding member 28. The number of case mounting holes 29 is not limited to four.

[0033] The case mounting hole 29 is a stepped hole and has a small diameter hole 30 located on the upper side and a large diameter hole (not shown) located on the lower side. The holding member 28 has a base mounting hole 31 for mounting to the second base member 10. The base mounting hole 31 is circular in a plan view and penetrates the holding member 28 in the up-down direction D1. In the illustrated example, two base mounting holes 31 are located on the right edge of the holding member 28. The two base mounting holes 31 are arranged spaced apart in the length direction of the right edge of the holding member 28. The number of base mounting holes 31 is not limited to two.

[0034] The holding member 28 and the second base member 10 are positioned by engaging portions that engage with each other. For this reason, in this embodiment, a concave engaging portion (not shown) is provided on the holding member 28. The engaging portion of the holding member 28 is provided on the lower surface of the holding member 28 so as to be recessed upward. The engaging portion of the holding member 28 has a circular shape when viewed from the bottom. In the illustrated example, one engaging portion is provided on the front edge portion of the holding member 28. In this embodiment, the engaging portion 23 of the second base member 10 is used as the engaging portion that engages with the engaging portion of the holding member 28.

[0035] The engaging portion 23 of the second base member 10 is used when positioning the first base member 9 and the second base member 10. To position the holding member 28 and the second base member 10, the lower surface of the holding member 28 is brought into contact with the upper surface of the second base member 10, and the convex engaging portion 23 of the second base member 10 is inserted into the concave engaging portion of the holding member 28.

[0036] 5 and 7 , with one plate surface of the retaining member 28 abutting against a predetermined side surface of the rotating shaft case 3, the retaining member 28 is attached to the rotating shaft case 3 by screwing a bolt 32 into the rotating shaft case 3 through the case mounting hole 29 of the retaining member 28. Thus, the retaining member 28 is detachably attached to the rotating shaft case 3. With the retaining member 28 attached to the rotating shaft case 3, the head of the bolt 32 is received in the large-diameter hole of the case mounting hole 29. Therefore, the head of the bolt 32 does not protrude downward from the retaining member 28.

[0037] 5 and 6 , the other plate surface of the holding member 28 is abutted against the upper surface of the second base member 10 attached to the additional axis installation section 5, and the engaging portion 23 of the second base member 10 is inserted into the engaging portion of the holding member 28. Then, bolts 33 are threaded through the base mounting holes 31 of the holding member 28 and into the base fixing holes 19 of the second base member 10, thereby attaching the holding member 28 to the second base member 10. Thus, the holding member 28 is detachably attached to the second base member 10. In this embodiment, when attaching the holding member 28 to the second base member 10, the base fixing holes 19 used to attach the first base member 9 to the second base member 10 are used. Therefore, in this embodiment, there is no need to provide additional screw holes for fixing the holding member 28 to the second base member 10.

[0038] In this way, the rotating shaft case 3 is attached to the second base member 10 by the holding member 28. When the rotating shaft case 3 is attached to the second base member 10, the axial direction of the additional shaft 2 is along the left-right direction D3. In this case, the axial direction of the additional shaft 2 intersects with the axial direction of the additional shaft 2 in the first state. Here, the state in which the rotating shaft case 3 with the first base member 9 attached is attached to the second base member 10 with the additional shaft installation part 5 attached, with the additional shaft 2 aligned in the axial direction intersecting the axial direction of the additional shaft 2 in the first state, is referred to as the "second state."

[0039] In the second state, the rotating shaft case 3 is detachably attached via the holding member 28 to the second base member 10, which is attached to the additional shaft installation section 5. The rotating shaft case 3 is turned sideways when changing from the first state to the second state. Therefore, in the second state, the axial direction of the additional shaft 2 intersects with the axial direction of the additional shaft 2 in the first state, so that the lower end of the additional shaft 2 can be exposed. This allows maintenance and inspection of the lower end of the additional shaft 2.

[0040] After the maintenance work is completed, the rotating shaft case 3 is returned to the first state. Specifically, after the holding member 28 is removed from the rotating shaft case 3 and the second base member 10, the first base member 9 to which the rotating shaft case 3 is attached is attached to the second base member 10. In this way, in this embodiment, the first state and the second state can be changed.

[0041] In this embodiment, a shim (not shown) may be used to adjust the accuracy of the posture of the additional shaft 2 provided in the rotating shaft case 3. The shim is a thin metal plate. The shim is provided at least either between the bottom surface of the rotating shaft case 3 and the top surface of the first base member 9, or between the bottom surface of the second base member 10 and the top surface of the additional shaft installation section 5.

[0042] In the case of the additional shaft mounting structure 1 of this embodiment, the rotating shaft case 3 having the additional shaft 2 is attached to the additional shaft installation section 5 of the machine tool 4 via the base member 6. Therefore, with the first base member 9 attached to the rotating shaft case 3, the first base member 9 can be attached and detached to the second base member 10 attached to the additional shaft installation section 5. Therefore, according to the additional shaft mounting structure 1 of this embodiment, after the rotating shaft case 3 is removed from the additional shaft installation section 5, it can be returned to its original position.

[0043] In the case of the additional shaft mounting structure 1 of this embodiment, the first base member 9 is detachably attached to the rotating shaft case 3. Therefore, according to the additional shaft mounting structure 1 of this embodiment, the first base member 9, which is a flange for mounting the rotating shaft case 3 to the additional shaft installation portion 5, and the additional shaft 2 can be separate bodies.

[0044] In the case of the additional shaft mounting structure 1 of this embodiment, a shim for adjusting the attitude of the additional shaft 2 is provided between the lower surface of the rotating shaft case 3 and the upper surface of the first base member 9, and between the lower surface of the second base member 10 and the upper surface of the additional shaft installation section 5. In the case of the additional shaft mounting structure 1 of this embodiment, the additional shaft 2 can be removed from the additional shaft installation section 5 by removing the first base member 9 from the second base member 10. Therefore, according to the additional shaft mounting structure 1 of this embodiment, it is not necessary to remove the shim when removing the additional shaft 2 from the additional shaft installation section 5.

[0045] The additional shaft mounting structure 1 of this embodiment can be changed between a first state and a second state. Therefore, according to the additional shaft mounting structure 1 of this embodiment, maintenance of the lower end of the additional shaft 2 can be easily performed, and the additional shaft 2 can be easily returned to its original position after maintenance.

[0046] In the case of the additional shaft mounting structure 1 of this embodiment, in the second state, the rotating shaft case 3 is detachably mounted via the holding member 28 to the second base member 10, which is mounted to the additional shaft installation part 5. Therefore, according to the additional shaft mounting structure 1 of this embodiment, the rotating shaft case 3 can be easily mounted to the second base member 10 in a state in which the rotating shaft case 3 is laid on its side.

[0047] According to the present embodiment described above, the rotary shaft case 3 having the additional shaft 2 is detachably attached to the additional shaft installation section 5 of the machine tool 4 by the base member 6. Therefore, it is possible to provide an additional shaft mounting structure 1 that can easily perform the mounting work after maintenance of the additional shaft 2, has excellent versatility, and can mount the additional shaft 2 with high precision.

[0048] Although the present disclosure has been described in detail, the present disclosure is not limited to the above-described embodiments. Various additions, substitutions, modifications, partial deletions, etc. are possible within the scope of the gist of the present disclosure, or within the scope of the gist of the present disclosure derived from the content of the claims and their equivalents. In the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0049] For example, in the above embodiment, the first base member 9 is attached to the second base member 10 by the bolts 27, but the first base member 9 may be detachably attached to the second base member 10 by means other than the bolts 27. In the above embodiment, the first base member 9 and the second base member 10 have a generally rectangular shape in plan view, but this is not limiting.

[0050] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) An additional shaft mounting structure (1) is an additional shaft mounting structure including a base member (6) that connects a rotating shaft case (3) having an additional shaft (2) and an additional shaft installation section (5) of a machine tool (4), the base member (6) having a first base member (9) detachably attached to the rotating shaft case (3) and a second base member (10) detachably attached to the additional shaft installation section (5), and the first base member (9) and the second base member (10) are positioned by engaging sections (22, 23) that engage with each other.

[0051] (Appendix 2) In Appendix 1, the additional shaft mounting structure (1) is preferably changeable between a first state in which the rotating shaft case (3) is mounted to the second base member (10) by the first base member (9), and a second state in which the rotating shaft case (3) is mounted to the second base member (10) with the first base member (9) attached so that the additional shaft (2) is aligned along an axial direction that intersects the axial direction of the additional shaft (2) in the first state.

[0052] (Supplementary Note 3) In the case of Supplementary Note 2, in the additional shaft mounting structure (1), in the second state, it is preferable that the rotating shaft case (3) is attached to the second base member (10) via a holding member (28).

[0053] REFERENCE SIGNS LIST 1 Additional axis mounting structure 2 Additional axis 3 Rotating axis case 4 Machine tool 5 Additional axis installation section 6 Base member 9 First base member 10 Second base member 22 Engagement section 23 Engagement section 28 Holding member

Claims

1. An additional axis mounting structure comprising a base member that couples a rotary shaft case having an additional axis to an additional axis installation portion of a machine tool, wherein the base member includes a first base member detachably attached to the rotary shaft case and a second base member detachably attached to the additional axis installation portion, and the first base member and the second base member are positioned by engaging portions that engage with each other.

2. The additional axis mounting structure according to claim 1, wherein it is possible to change between a first state in which the rotary shaft case is attached to the second base member by the first base member and a second state in which the rotary shaft case in a state where the first base member is attached is attached to the second base member such that the additional axis extends along an axial direction intersecting the axial direction of the additional axis in the first state.

3. The additional axis mounting structure according to claim 2, wherein in the second state, the rotary shaft case is attached to the second base member via a holding member.

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