Speed reduction mechanism of tool exchange device

Abstract

A speed reduction mechanism of a tool exchange device according to the present disclosure comprises: a hollow casing; a hollow gear that is provided in the casing and that has, on an outer circumferential part thereof, gear wheel parts at at least two coaxial locations; at least two bearings that each have an outer ring to which the inner circumferential surface of the gear is fixed; and a support shaft that holds inner rings of the bearings. The support shaft has a shoulder part that restricts the inner ring of one bearing, among the bearings, from moving toward one end in the axial direction. The support shaft is fixed to the casing, in a state where one end surface in the axial direction of the inner ring of said one bearing is in contact with the shoulder part, and the other end surface in the axial direction of the inner ring of said one bearing is in contact with the casing.

Description

Tool changer reduction mechanism

[0001] The present disclosure relates to a speed reduction mechanism of a tool changer provided in a machine tool.

[0002] Conventionally, tool changers that automatically change tools attached to the spindle of a machine tool are known. The tool changer typically has a tool magazine that holds a plurality of tools, and the tool magazine can be rotated by a motor. In a tool changer configured in this manner, a reduction mechanism is provided between the tool magazine and the motor. The reduction mechanism used in the tool changer of the machine tool has a counter gear. This counter gear is subjected to a gear separating force in two different directions during rotation. Therefore, the counter gear is preferably supported by two or more bearings to support the moment generated by the gear rotation and the separating force.

[0003] Japanese Unexamined Patent Publication No. 58-177248

[0004] The inner and outer rings of the bearings that support the counter gear of the reduction mechanism are generally fixed with a lock nut or a C-ring, or by being held down with a part such as a cover. As mentioned above, when two or more bearings are used, a fixing part for fixing the bearing is required for each bearing, so the number of fixing parts increases by the number of bearings. As the number of fixing parts increases, more space is required to install the fixing parts, leading to an increase in the size of the reduction mechanism.

[0005] In order to solve the above-mentioned problems, there is a demand for a reduction mechanism for a tool changer that can reduce the number of parts and enable a space-saving design.

[0006] The reduction mechanism of the tool changer disclosed herein comprises a hollow casing, a hollow gear provided within the casing and having gear portions on its outer periphery at least two coaxial locations, at least two bearings having outer rings to which the inner periphery of the gear is fixed, and a support shaft on which the inner rings of the bearings are held, the support shaft having a shoulder portion that restricts movement of the inner ring of one of the bearings toward one end in the axial direction, and the support shaft is fixed to the casing with one axial end face of the inner ring of the one bearing in contact with the shoulder portion and the other axial end face of the inner ring of the one bearing in contact with the casing.

[0007] 1 is a schematic cross-sectional view showing a reduction mechanism of a tool changer according to a first embodiment of the present invention; FIG. 2 is a schematic cross-sectional view showing a reduction mechanism of a tool changer according to a second embodiment of the present invention; FIG. 3 is a schematic cross-sectional view showing a reduction mechanism of a tool changer according to a third embodiment of the present invention;

[0008] A speed reduction mechanism of a tool changer according to one aspect of the present disclosure will be described below with reference to the drawings. A speed reduction mechanism 1 of a tool changer according to a first embodiment will be described with reference to FIG. 1 . The speed reduction mechanism 1 of the tool changer includes a casing 2, a gear 3, bearings 4 and 5, a support shaft 6, and a fixing means 7. Hereinafter, the axial direction of the bearings 4 and 5 is defined as an axial direction J1. Hereinafter, one end side of the axial direction J1 is defined as a J11 side, and the other end side of the axial direction J1 is defined as a J12 side.

[0009] Here, the tool changer applied to a machine tool is a device that automatically changes tools attached to the spindle of the machine tool and has a tool magazine that holds a plurality of tools. The tool changer can change the tools attached to the spindle of the machine tool by rotating the tool magazine. To rotate the tool magazine, a magazine gear 9 is rotated by a motor 8. The magazine gear 9 is connected to a gear portion 11 of a drive shaft 10 of the motor 8 via a reduction mechanism 1 of the tool changer according to the first embodiment.

[0010] As shown in FIG. 1 , the casing 2 is hollow. The casing 2 accommodates a gear 3, bearings 4 and 5, a support shaft 6, and a fixing means 7, which will be described later. The casing 2 may be integral with or separate from a casing that accommodates a rotating mechanism such as a magazine gear 9 and a casing that accommodates a motor 8. The inner surface of the casing 2 has a fixing portion 12 for fixing the support shaft 6. The fixing portion 12 is cylindrical and protrudes into the casing 2 from the inner surface of the casing 2, opening into the casing 2. A female thread is formed on the inner circumferential surface of the cylindrical fixing portion 12. As a result, the inner hole of the fixing portion 12 is a threaded hole. In this way, the casing 2 has a female thread portion 13.

[0011] The gear 3 is hollow. In the illustrated example, the gear 3 is substantially cylindrical and extends along the axial direction J1. The gear 3 has gear portions 14, 15 at two coaxial locations on its outer periphery. A large-diameter portion 16 extending radially outward in a flange-like shape is provided at one end J11 of the axial direction J1 of the cylindrical portion of the gear 3. The outer periphery of the large-diameter portion 16 has a plurality of teeth. As a result, the gear 3 has the gear portion 14 at the one end J11 of the axial direction J1. At the other end J12 of the axial direction J1 of the cylindrical portion of the gear 3, the outer periphery has a plurality of teeth. As a result, the gear 3 has the gear portion 15 at the other end J12 of the axial direction J1. The gear portion 14 has a larger diameter than the gear portion 15. Note that the gear 3 may have gear portions at three or more coaxial locations on its outer periphery. That is, the gear 3 only needs to have gear portions on the outer periphery at least at two locations on the same axis.

[0012] The inner hole 17 of the cylindrical gear 3 is a stepped hole, and has, in order from one end J11 in the axial direction J1, a large-diameter hole 18, a small-diameter hole 19, and a medium-diameter hole 20. With this configuration, a stepped first shoulder 21 is provided between the small-diameter hole 19 and the medium-diameter hole 20, and a stepped second shoulder 22 is provided between the small-diameter hole 19 and the large-diameter hole 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 closer to the other end J12 in the axial direction J1 than the second shoulder 22.

[0013] The gear 3 configured as described above is provided in the casing 2. The gear 3 is fixed to two bearings 4, 5 provided on a support shaft 6 (described later). Of the two bearings 4, 5, the first bearing 4 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, when the gear 3 is fixed to the first bearing 4, the first bearing 4 is located in the inner hole 17 of the gear 3. In the illustrated example, the inner circumferential surface of a medium-diameter hole 20 located at the other end J12 of the gear 3 in the axial direction J1 is fixed to the outer ring 24 of the first bearing 4. Therefore, the first bearing 4 is located in the medium-diameter hole 20 of the gear 3. The other of the two bearings 4, 5, the second bearing 5, is, for example, a ball bearing and has an inner ring 25 and an outer ring 26. The inner peripheral surface of the gear 3 is fixed to the outer ring 26 of the second bearing 5. Therefore, when the gear 3 is fixed to the second bearing 5, the second bearing 5 is located in the inner hole 17 of the gear 3. In the illustrated example, the outer ring 26 of the second bearing 5 is fixed to the inner peripheral surface of a large diameter hole 18 located on one end J11 of the gear 3 in the axial direction J1. Therefore, the second bearing 5 is located within the large diameter hole 18 of the gear 3, and is disposed with a gap in the axial direction J1 from the first bearing 4. Note that the first bearing 4 and the second bearing 5 are not limited to ball bearings.

[0014] The inner ring 23 of the first bearing 4 and the inner ring 25 of the second bearing 5 are held by a support shaft 6. The support shaft 6 is columnar and extends along the axial direction J1. The support shaft 6 is stepped and approximately cylindrical, and has, in order from one end J11 in the axial direction J1, a medium-diameter portion 27, a large-diameter portion 28, and a small-diameter portion 29. With this configuration, a stepped shoulder portion 30 is provided between the large-diameter portion 28 and the small-diameter portion 29, and a stepped shoulder portion 31 is provided between the large-diameter portion 28 and the medium-diameter portion 27. Therefore, the outer peripheral surface of the support shaft 6 has an annular shoulder portion 30 and an annular shoulder portion 31. The shoulder portion 30 is located closer to the other end J12 in the axial direction J1 than the shoulder portion 31.

[0015] The end face of one end J11 in the axial direction J1 of the support shaft 6 has a recess 32 that opens to the one end J11 in the axial direction J1. A female thread is formed on the inner peripheral surface of the recess 32. Therefore, the recess 32 is a threaded hole. A male thread is formed on the outer peripheral surface of the other end J12 in the axial direction J1 of the support shaft 6. In the illustrated example, a male thread is formed on the outer peripheral surface of the tip of the small diameter portion 29. Therefore, the support shaft 6 has a male thread portion 33 on the other end J12 in the axial direction J1.

[0016] The support shaft 6 is mounted on the casing 2 so as not to rotate around its axis. Specifically, the male threaded portion 33 of the support shaft 6 is screwed into the female threaded portion 13 of the casing 2, and a bolt 35 is screwed into the recess 32 of the support shaft 6 through a through-hole in the casing 2, thereby fixing the support shaft 6 to the casing 2 while positioned within the casing 2. The support shaft 6 is mounted on the casing 2 so as to bridge between opposing wall portions of the casing 2. Note that in the illustrated example, the support shaft 6 has the male threaded portion 33 and the casing 2 has the female threaded portion 13, but this configuration may be reversed. That is, the casing 2 may have the male threaded portion and the support shaft 6 may have the female threaded portion. Therefore, in the first embodiment, it is sufficient that one of the support shaft 6 and the casing 2 has the male threaded portion and the other has the female threaded portion.

[0017] As shown in FIG. 1 , the first bearing 4 is provided on the outer peripheral surface of the support shaft 6. Specifically, the first bearing 4 is provided 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 on the small diameter portion 29 of the support shaft 6. The second bearing 5 is provided on the outer peripheral surface of the support shaft 6. Specifically, the second bearing 5 is provided on the support shaft 6 by holding the inner ring 25 of the second bearing 5 on the outer peripheral surface of the medium diameter portion 27 of the support shaft 6. Therefore, the second bearing 5 is located on the medium diameter portion 27 of the support shaft 6.

[0018] As described above, the inner peripheral surface of the gear 3 is fixed to the outer rings 24, 26 of the two bearings 4, 5 provided on the support shaft 6 in this manner. Therefore, the gear 3 is rotatably provided on the support shaft 6 fixed to the casing 2 via the first bearing 4 and the second bearing 5. With the gear 3 provided on the support shaft 6 fixed to the casing 2, the gear portion 14 of the gear 3 meshes with the gear portion 11 provided on the drive shaft 10 of the motor 8, and the gear portion 15 of the gear 3 meshes with the magazine gear 9.

[0019] With the gear 3 mounted on the support shaft 6 fixed to the casing 2, the inner ring 23 of the first bearing 4 is sandwiched between a shoulder 30 of the support shaft 6 and a fixed portion 12 of the casing 2. Specifically, one end face 36 located on one end side J11 in the axial direction J1 of the inner ring 23 of the first bearing 4 is in contact with the shoulder 30 of the support shaft 6, and another end face 37 located on the other end side J12 in the axial direction J1 of the inner ring 23 of the first bearing 4 is in contact with the tip surface of the fixed portion 12. Therefore, in the first embodiment, the support shaft 6 is fixed to the casing 2 with the 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 casing 2.

[0020] As described above, one end surface 36 of the inner ring 23 of the first bearing 4 is in contact with the shoulder 30 of the support shaft 6. Therefore, in a state in which the gear 3 is provided on the support shaft 6 fixed to the casing 2, the shoulder 30 of the support shaft 6 restricts movement of the inner ring 23 of the first bearing 4 toward the one end J11 in the axial direction J1.

[0021] With the gear 3 mounted on the support shaft 6 fixed to the casing 2, the outer ring 24 of the first bearing 4 is in contact with the first shoulder 21 of the gear 3, and the outer ring 26 of the second bearing 5 is in contact with the second shoulder 22 of the gear 3. Specifically, one end face 39 located on one end side J11 in the axial direction J1 of the outer ring 24 of the first bearing 4 is in contact with the first shoulder 21, and the other end face 40 located on the other end side J12 in the axial direction J1 of the outer ring 26 of the second bearing 5 is in contact with the second shoulder 22.

[0022] 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 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 movement of the outer ring 26 of the second bearing 5 toward the other end J12 in the axial direction J1.

[0023] With the gear 3 mounted on the support shaft 6 fixed to the casing 2, the inner ring 25 of the second bearing 5 is sandwiched between a fixing means 7 that fixes the second bearing 5 to the support shaft 6 and a shoulder 31 of the support shaft 6. The fixing means 7 is, for example, a lock nut. When the fixing means 7 is a lock nut, the fixing means 7 is attached to the support shaft 6 by being screwed onto a male thread formed on the outer peripheral surface of the support shaft 6. When the fixing means 7 is a lock nut, one end face 45 located on one end side J11 in the axial direction J1 of the inner ring 25 of the second bearing 5 contacts an end face 44 located on the other end side J12 in the axial direction J1 of the fixing means 7, and the other end face 43 located on the other end side J12 in the axial direction J1 of the inner ring 25 of the second bearing 5 contacts the shoulder 31 of the support shaft 6.

[0024] In the first embodiment, the gear 3 is rotatably mounted on the support shaft 6 via the two bearings 4 and 5, but it may be rotatably mounted on the support shaft 6 via three or more bearings. In other words, the reduction gear mechanism 1 of the first embodiment is required to have at least two bearings.

[0025] In the case of the reduction gear mechanism 1 of the tool changer according to the first embodiment, the gear 3 is rotatably held on the support shaft 6 via two bearings 4, 5. Of the two bearings 4, 5, the first bearing 4 is in contact with the fixed portion 12 of the casing 2, the shoulder 30 of the support shaft 6, and the first shoulder 21 of the gear 3, while the other bearing, the second bearing 5, is in contact with the fixing means 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 gear mechanism 1 of the tool changer according to the first embodiment, it is possible to reduce the number of parts for holding the bearings 4, 5 on the support shaft 6 and to improve rigidity compared to a case where only one bearing is used.

[0026] In the case of the reduction gear mechanism 1 of the tool changer according to the first embodiment, the support shaft 6 can be fixed to the casing 2 by screwing the male thread portion 33 of the support shaft 6 into the female thread portion 13 of the casing 2. Therefore, according to the reduction gear mechanism 1 of the tool changer according to the first embodiment, the work of attaching the support shaft 6 to the casing 2 and the work of removing the support shaft 6 from the casing 2 can be easily performed.

[0027] In the case of the reduction mechanism 1 of the tool changer according to the first embodiment, the gear 3 is sandwiched between the first bearing 4 and the second bearing 5. Therefore, according to the reduction mechanism 1 of the tool changer according to the first embodiment, the position of the gear 3 relative to the support shaft 6 can be fixed with a simple configuration.

[0028] Next, a speed reduction mechanism of a tool changer according to a second embodiment will be described with reference to Fig. 2. Note that components having the same reference numerals as those in the first embodiment have the same functions, and therefore, their description may be omitted below.

[0029] In the first embodiment, the first bearing 4 directly contacts the fixed portion 12 of the casing 2, but in the speed reduction mechanism 1a of the tool changer according to the second embodiment, the first bearing 4 contacts the casing 2 via a contact member 46. In the illustrated example, the contact member 46 is annular, and is fixed to the tip surface of the fixed portion 12 of the casing 2. With this configuration, the other end surface 37 of the inner ring 23 of the first bearing 4 contacts the tip surface of the fixed portion 12 of the casing 2 via the contact member 46.

[0030] Next, a speed reduction mechanism of a tool changer according to a third embodiment will be described with reference to Fig. 3. Note that components having the same reference numerals as those in the first embodiment have the same functions, and therefore, their description may be omitted below.

[0031] The speed reduction mechanism 1b of the tool changer according to the third embodiment differs from that of the first embodiment in the configuration of the fixing means 7. In the first embodiment, the fixing means 7 is a lock nut screwed onto the support shaft 6, but in the third embodiment, the fixing means 7 is an annular snap ring. When the fixing means 7 is a snap ring, the fixing means 7 is fixed to the support shaft 6 by being inserted into a groove 48 formed along the circumferential direction on the outer peripheral surface of the support shaft 6. When the fixing means 7 is fixed to the support shaft 6, one end face 45 of the inner ring 25 of the second bearing 5 is in contact with the fixing means 7.

[0032] According to at least one embodiment described above, the two bearings 4, 5 are fixed by the support shaft 6 having the shoulders 30, 31, the gear 3 having the first shoulder 21 and the second shoulder 22, and the casing 2. Therefore, it is possible to provide the reduction mechanism 1 of the tool changer that can reduce the number of parts and enable a space-saving design.

[0033] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, 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.

[0034] The following supplementary note is further disclosed regarding the above embodiment. (Supplementary note 1) A reduction mechanism (1) of a tool changer includes a hollow casing (2), a hollow gear (3) provided in the casing (2) and having gear portions (14, 15) on the outer periphery at least two positions on the same axis, at least two bearings (4, 5) having outer rings (24, 26) to which the inner periphery of the gear (3) is fixed, and a support shaft (6) on which inner rings (23, 25) of the bearings (4, 5) are held. ), the support shaft (6) has a shoulder portion (30) that restricts movement of the inner ring (23) of one of the bearings (4) toward one end side (J11) in the axial direction (J1), and the support shaft (6) is fixed to the casing (2) in a state in which one end face (36) of the inner ring (23) of the one bearing (4) in the axial direction (J1) contacts the shoulder portion (30) and the other end face (37) of the inner ring (23) of the one bearing (4) in the axial direction (J1) contacts the casing (2).

[0035] (Supplementary Note 2) The reduction gear mechanism (1) of the tool changer according to Supplementary Note 1, further comprising: a first bearing (4) that is one of the bearings and a second bearing (5) that is disposed at an interval from the first bearing (4); a fixing means (7) that fixes the second bearing (5) to the support shaft (6); and an inner peripheral surface of the gear (3) that is fixed to the outer ring (24) of the first bearing (4) in the axial direction ( The bearing may have a first shoulder (21) that restricts movement of an outer ring (24) of the first bearing (4) toward one end (J11) of the outer ring (24) of the second bearing (5) in the axial direction (J1), and a second shoulder (22) that restricts movement of an outer ring (26) of the second bearing (5) toward the other end (J12) of the outer ring (24) of the second bearing (5), wherein one end face (39) of the outer ring (24) of the first bearing (4) in the axial direction (J1) is in contact with the first shoulder (21), and the other end face (40) of the outer ring (26) of the second bearing (5) in the axial direction (J1) is in contact with the second shoulder (22).

[0036] (Supplementary Note 3) In the reduction mechanism (1) of the tool changer in Supplementary Note 1 or Supplementary Note 2, one of the support shaft (6) and the casing (2) may have a male thread portion (33) and the other may have a female thread portion (13), and the support shaft (6) may be fixed to the casing (2) by screwing the male thread portion (33) into the female thread portion (13).

[0037] REFERENCE SIGNS LIST 1 reduction mechanism of tool changer 2 casing 3 gear 4 first bearing 5 second bearing 6 support shaft 7 fixing means 13 female thread portion 14 gear portion 15 gear portion 21 first shoulder portion 22 second shoulder portion 23 inner ring 24 outer ring 26 outer ring 30 shoulder portion 33 male thread portion 36 one end surface 37 other end surface 39 one end surface 40 other end surface

Claims

1. A reduction mechanism for a tool changer comprising: a hollow casing; a hollow gear provided within the casing and having gear portions on its outer periphery at least two coaxial locations; at least two bearings having outer rings to which the inner periphery of the gear is fixed; and a support shaft on which the inner rings of the bearings are held, wherein the support shaft has a shoulder portion that restricts movement of the inner ring of one of the bearings toward one end in the axial direction, and the support shaft is fixed to the casing with one end face in the axial direction of the inner ring of the one bearing in contact with the shoulder portion and the other end face in the axial direction of the inner ring of the one bearing in contact with the casing.

2. A reduction gear mechanism for a tool changer as set forth in claim 1, wherein the bearings are two bearings having outer rings to which the inner peripheral surface of the gear is fixed, the bearing comprising a first bearing which is the one bearing, and a second bearing which is arranged at an interval from the first bearing, and further comprising fixing means for fixing the second bearing to the support shaft, the inner peripheral surface of the gear having a first shoulder portion which restricts movement of the outer ring of the first bearing towards one end in the axial direction, and a second shoulder portion which restricts movement of the outer ring of the second bearing towards the other end in the axial direction, and wherein one end face in the axial direction of the outer ring of the first bearing contacts the first shoulder portion, and the other end face in the axial direction of the outer ring of the second bearing contacts the second shoulder portion.

3. A reduction mechanism for a tool changer as described in claim 1 or 2, wherein one of the support shaft and the casing has a male threaded portion and the other has a female threaded portion, and the support shaft is fixed to the casing by screwing the male threaded portion into the female threaded portion.

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