Speed reduction mechanism for tool changer

Abstract

The reduction mechanism of the tool changer of the present disclosure has a hollow housing, a hollow gear provided in the housing and having gear portions at at least two outer peripheral portions coaxially, at least two bearings each having an outer race to which an inner peripheral surface of the gear is fixed, and a support shaft holding inner races of the bearings, the support shaft having a shoulder portion to restrict movement of an inner race of one of the bearings toward one end side in an axial direction, the inner race of the one bearing being in contact with the shoulder portion at one end surface in the axial direction, and the inner race of the one bearing being in contact with the housing at the other end surface in the axial direction, the support shaft being fixed to the housing.

Description

Technical Field

[0001] This disclosure relates to a speed reduction mechanism for a tool changing device in a machine tool. Background Technology

[0002] Previously, a tool changer was known that automatically changed the tools mounted on the spindle of a machine tool. The tool changer typically had a tool magazine that held multiple tools, and the tool magazine could be rotated by a motor. In such a tool changer, a reduction gear was provided between the tool magazine and the motor. The reduction gear used in the machine tool's tool changer had a counterspindle gear. This counterspindle gear was subjected to gear separation forces in two different directions during rotation. Therefore, in order to support the bending moment generated by the rotation and separation forces of the gear, the counterspindle gear was preferably supported by two or more bearings.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 58-177248 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The inner and outer rings of the bearings supporting the countershaft gear of the reduction mechanism are typically secured using lock nuts or C-rings, or by being pressed together by a cover. When using two or more bearings as described above, each bearing requires a fixing component, thus increasing the number of fixing components corresponding to the number of bearings. This increase in the number of fixing components leads to a larger space for them, resulting in a larger reduction mechanism.

[0008] To eliminate the above problems, a speed reduction mechanism for a tool changer that can reduce the number of parts and achieve a space-saving design is desired.

[0009] Solution for solving the problem

[0010] The reduction mechanism of the tool changing device disclosed herein comprises: a hollow housing; a hollow gear disposed within the housing, having gear portions at at least two coaxial locations on its outer periphery; at least two bearings, each having an outer ring, the inner circumferential surface of the gear being fixed to the outer ring; and a support shaft holding the inner ring of the bearing, the support shaft having a shoulder that restricts the axial movement of the inner ring of one of the bearings toward one end of the bearing, wherein the support shaft is fixed to the housing when one axial end face of the inner ring of the bearing contacts the shoulder and the other axial end face of the inner ring of the bearing contacts the housing. Attached Figure Description

[0011] Figure 1 This is a schematic cross-sectional view showing the deceleration mechanism of the tool changing device according to Embodiment 1 of the present invention.

[0012] Figure 2 This is a schematic cross-sectional view showing the deceleration mechanism of the tool changing device according to Embodiment 2 of the present invention.

[0013] Figure 3 This is a schematic cross-sectional view showing the deceleration mechanism of the tool changing device according to Embodiment 3 of the present invention. Detailed Implementation

[0014] The reduction mechanism of one aspect of the tool changing device of this disclosure will now be described with reference to the accompanying drawings. Figure 1 The reduction mechanism 1 of the tool changing device according to Embodiment 1 will be described below. The reduction mechanism 1 of the tool changing device includes a housing 2, a gear 3, bearings 4 and 5, a support shaft 6, and a fixing unit 7. Hereinafter, the axial direction of bearings 4 and 5 will be defined as axial direction J1. One end of axial direction J1 will be designated as J11 side, and the other end of axial direction J1 will be designated as J12 side.

[0015] Here, the tool changer applied to the machine tool is a device that automatically exchanges the tools mounted on the spindle of the machine tool, and has a tool magazine that holds multiple tools. The tool changer can exchange the tools mounted on the spindle of the machine tool by rotating the tool magazine. In order to rotate the tool magazine, the tool magazine gear 9 is rotated by the motor 8. The tool magazine gear 9 is connected to the gear section 11 of the drive shaft 10 of the motor 8 via the reduction mechanism 1 of the tool changer of this embodiment 1.

[0016] like Figure 1 As shown, the housing 2 is hollow. Gears 3, bearings 4 and 5, support shaft 6, and fixing unit 7 (described later) are housed within the housing 2. The housing 2 can be integrated with the housing housing the rotating mechanism such as the tool magazine gear 9 and the housing housing the motor 8, or it can be separate from them. The inner surface of the housing 2 has a fixing part 12 for fixing the support shaft 6. The fixing part 12 is a cylindrical shape protruding from the inner surface of the housing 2 and opening into the housing 2. An internal thread is formed on the inner circumferential surface of the cylindrical fixing part 12. Thus, the inner hole of the fixing part 12 becomes a threaded hole. Therefore, the housing 2 has an internally threaded part 13.

[0017] Gear 3 is hollow. In the illustrated example, gear 3 is generally cylindrical and extends along the axial direction J1. Gear 3 has gear portions 14 and 15 at two coaxial outer peripheral locations. A large-diameter portion 16, extending radially outward in a flange shape, is provided at one end J11 of the cylindrical portion of gear 3 along the axial direction J1. Multiple teeth are provided on the outer peripheral surface of the large-diameter portion 16. Thus, gear 3 has gear portion 14 at one end J11 along the axial direction J1. At the other end J12 of the cylindrical portion of gear 3 along the axial direction J1, multiple teeth are provided on the outer peripheral surface of the cylindrical portion. Thus, gear 3 has gear portion 15 at the other end J12 along the axial direction J1. The diameter of gear portion 14 is larger than the diameter of gear portion 15. Alternatively, gear 3 may have gear portions at three or more coaxial outer peripheral locations. That is, gear 3 may have gear portions at at least two coaxial outer peripheral locations.

[0018] The inner bore 17 of the cylindrical gear 3 is a stepped bore, consisting of a large-diameter bore 18, a small-diameter bore 19, and a medium-diameter bore 20 sequentially from one end J11 along the axial direction. Due to this structure, a stepped first shoulder 21 is provided between the small-diameter bore 19 and the medium-diameter bore 20, and a stepped second shoulder 22 is provided between the small-diameter bore 19 and the large-diameter bore 18. Therefore, the inner circumferential surface of the gear 3 has an annular first shoulder 21 and an annular second shoulder 22. The first shoulder 21 is located at a position closer to the other end J12 along the axial direction than the second shoulder 22.

[0019] The gear 3, with the structure described above, is housed within the housing 2. The gear 3 is fixed to two bearings 4 and 5 located on the support shaft 6 (described later). The first bearing 4 of one of the bearings 4 and 5 is, for example, a ball bearing, and has an inner ring 23 and an outer ring 24. The inner circumferential surface of the gear 3 is fixed to the outer ring 24 of the first bearing 4. Therefore, with the gear 3 fixed to the first bearing 4, the first bearing 4 is located within the inner bore 17 of the gear 3. In the illustrated example, the inner circumferential surface of the pitch diameter bore 20 of the gear 3 located at the other end J12 of the axial direction J1 is fixed to the outer ring 24 of the first bearing 4. Therefore, the first bearing 4 is located within the pitch diameter bore 20 of the gear 3. The second bearing 5 of the other of the bearings 4 and 5 is, for example, a ball bearing, and has an inner ring 25 and an outer ring 26. The inner circumferential surface of the gear 3 is fixed to the outer ring 26 of the second bearing 5. Therefore, with gear 3 fixed to the second bearing 5, the second bearing 5 is located within the inner bore 17 of gear 3. In the illustrated example, the inner circumferential surface of the large-diameter bore 18 of gear 3 located at one end J11 in the axial direction is fixed to the outer ring 26 of the second bearing 5. Therefore, the second bearing 5 is located within the large-diameter bore 18 of gear 3 and is disposed with a gap between it and the first bearing 4 in the axial direction J1. Furthermore, the first bearing 4 and the second bearing 5 are not limited to ball bearings.

[0020] The inner ring 23 of the first bearing 4 and the inner ring 25 of the second bearing 5 are held in place by the support shaft 6. The support shaft 6 is cylindrical and extends along the axial direction J1. The support shaft 6 is a generally cylindrical shape with steps, and has a middle diameter portion 27, a large diameter portion 28, and a small diameter portion 29 sequentially from one end side J11 along the axial direction J1. Due to this structure, a stepped shoulder 30 is provided between the large diameter portion 28 and the small diameter portion 29, and a stepped shoulder 31 is provided between the large diameter portion 28 and the middle diameter portion 27. Therefore, the outer circumferential surface of the support shaft 6 has annular shoulder 30 and annular shoulder 31. The shoulder 30 is located at the other end side J12 along the axial direction J1, closer to the shoulder 31.

[0021] The end face of one end J11 of the support shaft 6 along the axial direction J1 has a recess 32 that opens toward the end J11 along the axial direction J1. An internal thread is formed on the inner circumferential surface of the recess 32. Therefore, the recess 32 is a threaded hole. An external thread is formed on the outer circumferential surface of the other end J12 of the support shaft 6 along the axial direction J1. In the illustrated example, an external thread is formed on the outer circumferential surface of the top end of the small diameter portion 29. Therefore, the support shaft 6 has an externally threaded portion 33 on the other end J12 along the axial direction J1.

[0022] The support shaft 6 is mounted on the housing 2 in a manner that prevents it from rotating around its axis. Specifically, the external thread 33 of the support shaft 6 is screwed into the internal thread 13 of the housing 2, and a bolt 35 is screwed into the recess 32 of the support shaft 6 through a through hole in the housing 2, thereby fixing the support shaft 6 to the housing 2 while it is located inside the housing 2. The support shaft 6 is mounted on the housing 2 in a manner that it is supported between opposing walls of the housing 2. In the illustrated example, the support shaft 6 has an external thread 33 and the housing 2 has an internal thread 13, but the structure could also be the opposite. That is, the housing 2 could have an external thread and the support shaft 6 could have an internal thread. Therefore, in this embodiment 1, it is sufficient that one of the support shaft 6 and the housing 2 has an external thread and the other has an internal thread.

[0023] like Figure 1 As shown, the first bearing 4 is disposed on the outer peripheral surface of the support shaft 6. Specifically, the first bearing 4 is disposed on the support shaft 6 by holding the inner ring 23 of the first bearing 4 on the outer peripheral surface of the small diameter portion 29 of the support shaft 6. Therefore, the first bearing 4 is located in the small diameter portion 29 of the support shaft 6. The second bearing 5 is disposed on the outer peripheral surface of the support shaft 6. Specifically, the second bearing 5 is disposed on the support shaft 6 by holding the inner ring 25 of the second bearing 5 on the outer peripheral surface of the middle diameter portion 27 of the support shaft 6. Therefore, the second bearing 5 is located in the middle diameter portion 27 of the support shaft 6.

[0024] As described above, the inner circumferential surface of gear 3 is fixed to the outer rings 24 and 26 of two bearings 4 and 5 provided on the support shaft 6. Therefore, gear 3 is rotatably mounted on the support shaft 6 fixed to the housing 2 via the first bearing 4 and the second bearing 5. When gear 3 is mounted on the support shaft 67 fixed to the housing 2, the gear portion 14 of gear 3 meshes with the gear portion 11 provided on the drive shaft 10 of motor 8, and the gear portion 15 of gear 3 meshes with the tool magazine gear 9.

[0025] With the gear 3 fixed to the support shaft 6 of the housing 2, the inner ring 23 of the first bearing 4 is sandwiched between the shoulder 30 of the support shaft 6 and the fixing part 12 of the housing 2. Specifically, one end face 36 of the inner ring 23 of the first bearing 4, located at one end J11 in the axial direction J1, contacts the shoulder 30 of the support shaft 6, and the other end face 37 of the inner ring 23 of the first bearing 4, located at the other end J12 in the axial direction J1, contacts the top surface of the fixing part 12. Therefore, in this embodiment 1, with one end face 36 of the inner ring 23 of the first bearing 4 in contact with the shoulder 30 and the other end face 37 of the inner ring 23 of the first bearing 4 in contact with the housing 2, the support shaft 6 is fixed to the housing 2.

[0026] As described above, one end face 36 of the inner ring 23 of the first bearing 4 contacts the shoulder 30 of the support shaft 6. Therefore, when the gear 3 is mounted on the support shaft 6 fixed to the housing 2, the shoulder 30 of the support shaft 6 restricts the inner ring 23 of the first bearing 4 from moving toward one end J11 in the axial direction J1.

[0027] With gear 3 mounted on the support shaft 6 fixed to housing 2, the outer ring 24 of the first bearing 4 contacts the first shoulder 21 of gear 3, and the outer ring 26 of the second bearing 5 contacts the second shoulder 22 of gear 3. Specifically, the end face 39 of the outer ring 24 of the first bearing 4 located at one end J11 in the axial direction J1 contacts the first shoulder 21, and the other end face 40 of the outer ring 26 of the second bearing 5 located at the other end J12 in the axial direction J1 contacts the second shoulder 22.

[0028] As described above, one end face 39 of the outer ring 24 of the first bearing 4 contacts the first shoulder 21 of the gear 3, and the other end face 40 of the outer ring 26 of the second bearing 5 contacts the second shoulder 22 of the gear 3. Therefore, the first shoulder 21 of the gear 3 restricts the movement of the outer ring 24 of the first bearing 4 toward one end J11 in the axial direction J1, and the second shoulder 22 of the gear 3 restricts the movement of the outer ring 26 of the second bearing 5 toward the other end J12 in the axial direction J1.

[0029] With gear 3 fixed to support shaft 6 of housing 2, the inner ring 25 of second bearing 5 is sandwiched between fixing unit 7, which fixes second bearing 5 to support shaft 6, and shoulder 31 of support shaft 6. Fixing unit 7 is, for example, a lock nut. When fixing unit 7 is a lock nut, fixing unit 7 is provided on support shaft 6 by screwing into external thread formed on the outer circumferential surface of support shaft 6. When fixing unit 7 is a lock nut, one end face 45 of inner ring 25 of second bearing 5 located at axial direction J1 (J11) contacts end face 44 of fixing unit 7 located at axial direction J1 (J12), and the other end face 43 of inner ring 25 of second bearing 5 located at axial direction J1 (J12) contacts shoulder 31 of support shaft 6.

[0030] In addition, in this embodiment 1, the gear 3 is rotatably mounted on the support shaft 6 via two bearings 4 and 5, but it can also be rotatably mounted on the support shaft 6 via three or more bearings. That is, the reduction mechanism 1 of this embodiment 1 only needs to have at least two bearings.

[0031] In the case of the reduction mechanism 1 of the tool changing device in Embodiment 1, the gear 3 is rotatably held on the support shaft 6 via two bearings 4 and 5. The first bearing 4 of one of the bearings 4 and 5 contacts the fixing part 12 of the housing 2, the shoulder 30 of the support shaft 6, and the first shoulder 21 of the gear 3, while the second bearing 5 of the other contact the fixing unit 7 fixed to the support shaft 6, the shoulder 31 of the support shaft 6, and the second shoulder 22 of the gear 3. Therefore, according to the reduction mechanism 1 of the tool changing device in Embodiment 1, the number of components used to hold the bearings 4 and 5 on the support shaft 6 can be reduced, and the rigidity can be improved compared to the case where there is only one bearing.

[0032] In the case of the reduction mechanism 1 of the tool changing device in this embodiment 1, the support shaft 6 can be fixed to the housing 2 by screwing the external thread 33 of the support shaft 6 into the internal thread 13 of the housing 2. Therefore, according to the reduction mechanism 1 of the tool changing device in this embodiment 1, the installation operation of the support shaft 6 to the housing 2 and the removal operation of the support shaft 6 from the housing 2 can be easily performed.

[0033] In the case of the reduction mechanism 1 of the tool changing device in this embodiment 1, the gear 3 is clamped between the first bearing 4 and the second bearing 5. Therefore, according to the reduction mechanism 1 of the tool changing device in this embodiment 1, the position of the gear 3 relative to the support shaft 6 can be fixed with a simple structure.

[0034] Next, use Figure 2 The deceleration mechanism of the tool changing device in Embodiment 2 will be described. Furthermore, components having the same reference numerals as those in Embodiment 1 are assumed to function the same way, therefore descriptions may be omitted hereafter.

[0035] In Embodiment 1, the first bearing 4 directly contacts the fixing portion 12 of the housing 2. However, in the reduction mechanism 1a of the tool changing device in Embodiment 2, the first bearing 4 contacts the housing 2 via a contact member 46. In the illustrated example, the contact member 46 is annular and fixed to the top surface of the fixing portion 12 of the housing 2. Due to this structure, the other end face 37 of the inner ring 23 of the first bearing 4 contacts the top surface of the fixing portion 12 of the housing 2 via the contact member 46.

[0036] Next, use Figure 3 The deceleration mechanism of the tool changing device in Embodiment 3 will be described. Furthermore, components having the same reference numerals as those in Embodiment 1 are assumed to have the same function, therefore descriptions may be omitted hereafter.

[0037] The structure of the fixing unit 7 in the reduction mechanism 1b of the tool changing device in Embodiment 3 differs from that in Embodiment 1. In Embodiment 1, the fixing unit 7 is a locking nut screwed into the support shaft 6, but in Embodiment 3, the fixing unit 7 is an annular retaining ring. When the fixing unit 7 is a retaining ring, the fixing unit 7 is fixed to the support shaft 6 by inserting it into a groove 48 formed circumferentially on the outer peripheral surface of the support shaft 6. With the fixing unit 7 fixed to the support shaft 6, one end face 45 of the inner ring 25 of the second bearing 5 contacts the fixing unit 7.

[0038] According to at least one embodiment described above, the two bearings 4 and 5 are fixed by a support shaft 6 having shoulders 30 and 31, a gear 3 having a first shoulder 21 and a second shoulder 22, and a housing 2. Therefore, a reduction mechanism 1 for a tool changer can be provided that reduces the number of components and achieves a space-saving design.

[0039] Although this disclosure has been described in detail, it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions may be made to these embodiments without departing from the spirit of this disclosure, or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments may also be implemented in combination. For example, in the embodiments described above, the order of each action and the order of each process are shown as an example, and are not limited thereto. The same applies to the use of numerical values ​​or formulas in the description of the embodiments described above.

[0040] Regarding the above-described embodiments, the following notes are further disclosed.

[0041] (Postscript 1)

[0042] A reduction mechanism (1) for a tool changing device comprises: a hollow housing (2); a hollow gear (3) disposed within the housing (2), having gear portions (14, 15) on at least two coaxial outer peripheral portions; at least two bearings (4, 5), each having an outer ring (24, 26), the inner peripheral surface of the gear (3) being fixed to the outer ring (24, 26); and a support shaft (6) holding the inner rings (23, 25) of the bearings (4, 5), the support shaft (6) having The shoulder (30) that restricts the movement of the inner ring (23) of one of the bearings (4, 5) toward one end (J11) of the axial direction (J1) is in contact with the shoulder (30) at one end face (36) of the inner ring (23) of the bearing (4) along the axial direction (J1) and the other end face (37) of the inner ring (23) of the bearing (4) along the axial direction (J1) is in contact with the housing (2), and the support shaft (6) is fixed to the housing (2).

[0043] (Postscript 2)

[0044] For the reduction mechanism (1) of the tool changing device, it is also possible that, based on Appendix 1, the bearings (4, 5) are two bearings, having one bearing, namely the first bearing (4), and a second bearing (5) disposed at a distance from the first bearing (4). The two bearings each have an outer ring (24, 26), and the inner circumferential surface of the gear (3) is fixed to the outer ring (24, 26). The reduction mechanism of the tool changing device also includes a fixing unit (7) for fixing the second bearing (5) to the support shaft (6). The inner circumferential surface of the gear (3) has a first shoulder (21) and a second shoulder. Part (22), the first shoulder (21) restricts the movement of the outer ring (24) of the first bearing (4) toward one end (J11) of the axial direction (J1), the second shoulder (22) restricts the movement of the outer ring (26) of the second bearing (5) toward the other end (J12) of the axial direction (J1), one end face (39) of the outer ring (24) of the first bearing (4) in contact with the first shoulder (21), and the other end face (40) of the outer ring (26) of the second bearing (5) in contact with the second shoulder (22).

[0045] (Note 3)

[0046] For the reduction mechanism (1) of the tool changing device, it is also possible that, based on Appendix 1 or Appendix 2, one of the support shaft (6) and the housing (2) has an external thread (33) and the other has an internal thread (13). The support shaft (6) is fixed to the housing (2) by screwing the external thread (33) into the internal thread (13).

[0047] Explanation of reference numerals in the attached figures

[0048] 1: Reduction mechanism of tool changing device; 2: Housing; 3: Gear; 4: First bearing; 5: Second bearing; 6: Support shaft; 7: Fixing unit; 13: Internal thread part; 14: Gear part; 15: Gear part; 21: First shoulder; 22: Second shoulder; 23: Inner ring; 24: Outer ring; 26: Outer ring; 30: Shoulder; 33: External thread part; 36: One end face; 37: The other end face; 39: One end face; 40: The other end face.

Claims

1. A reduction gear mechanism for a tool changing device, wherein, The speed reduction mechanism of the tool changing device includes: Hollow shell; A hollow gear, disposed within the housing, having gear portions at at least two coaxial locations on its outer periphery; At least two bearings, each having an outer ring, the inner circumferential surface of the gear being fixed to the outer ring; and A support shaft that holds the inner ring of the bearing. The support shaft has a shoulder that restricts the inner ring of one of the bearings from moving axially toward one end. The support shaft is fixed to the housing when one axial end face of the inner ring of the bearing contacts the shoulder and the other axial end face of the inner ring of the bearing contacts the housing.

2. The reduction mechanism of the tool changing device according to claim 1, wherein, The bearing consists of two bearings: a first bearing and a second bearing disposed at a distance from the first bearing. Each bearing has an outer ring, and the inner circumferential surface of the gear is fixed to the outer ring. The reduction mechanism of the tool changing device also includes a fixing unit for fixing the second bearing to the support shaft. The gear has a first shoulder and a second shoulder on its inner circumferential surface. The first shoulder restricts the outer ring of the first bearing from moving toward one end of the axial direction, and the second shoulder restricts the outer ring of the second bearing from moving toward the other end of the axial direction. One axial end face of the outer ring of the first bearing contacts the first shoulder, and the other axial end face of the outer ring of the second bearing contacts the second shoulder.

3. The reduction mechanism of the tool changing device according to claim 1 or 2, wherein, One of the support shaft and the housing has an external thread, and the other has an internal thread. The support shaft is fixed to the housing by being screwed into the internal thread by the external thread.

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