Duplex rotary dividing device

Abstract

The invention provides a structure capable of reducing the interval between two sets of rotary indexing parts in a duplex rotary indexing device provided with the two sets of rotary indexing parts. The duplex rotary indexing device is provided with two sets of rotary indexing parts, each rotary indexing part comprises a driving shaft which is driven by a driving motor to rotate, a disc-shaped driven part which is arranged on a main shaft, and a driving part which is provided on the driving shaft and is provided with a spiral groove which is directly or indirectly clamped with the driven part. One side of one end of the driving shaft is supported by the frame through a bearing retainer internally provided with a thrust bearing, one side of the other end of the driving shaft is supported by the frame through a radial bearing, and the driving shafts of the two rotary indexing parts are connected through a connecting component. The drive motor is connected to an end portion of the drive shaft in one of the rotary indexing portions on the opposite side from the connection member side, and the other end of the drive shaft in one of the rotary indexing portions is connected to the other end of the drive shaft in the other rotary indexing portion.

Description

Technical Field

[0001] The present invention relates to a double-linked rotary indexing device, which has two sets of rotary indexing parts, the rotary indexing parts including a main shaft which is supported in a frame so as to be rotatable and has a rotating object part installed on one end side, and a driving transmission mechanism which transmits the rotation of the output shaft of the driving motor to the main shaft, the driving transmission mechanism including a driving shaft which is rotationally driven by the driving motor, a disc-shaped driven part installed on the main shaft, and a driving part which has a spiral groove which directly or indirectly engages with the driven part and is arranged on the driving shaft, the driving shaft is supported by the frame on one side of one end via a bearing retainer which has a thrust bearing installed therein, and is supported by the frame on one side of the other end via a radial bearing, the driving shafts of the two rotary indexing parts are connected by a connecting part, and the driving motor is connected to the end of the driving shaft on the side opposite to the connecting part side in one of the rotary indexing parts. Background Art

[0002] In the field of machine tools, a so-called multi-link rotary indexing device is known that includes a plurality of rotary indexing units for indexing the angular position of a workpiece. In the multi-link rotary indexing device, the rotary indexing unit includes a main shaft supported in a frame so as to be rotatable and a drive transmission mechanism for transmitting the rotation of the output shaft of a drive motor to the main shaft.

[0003] In addition, in the rotary indexing part, the spindle is configured to mount a rotating object component (e.g., a workbench for fixing a workpiece, etc.) on one end side thereof. Furthermore, the drive transmission mechanism is configured to include a drive shaft driven by a drive motor, a disc-shaped driven component mounted on the spindle, and a drive component having a spiral groove directly or indirectly engaged with the driven component and disposed on the drive shaft. Furthermore, as an example of a multi-link rotary indexing device having a plurality of such rotary indexing parts, there is a device disclosed in Patent Document 1.

[0004] Regarding the multi-link rotary indexing device disclosed in the patent document 1, in detail, in each rotary indexing part (indexing unit) of the multi-link rotary indexing device, its drive transmission mechanism is a worm gear mechanism, and the worm gear mechanism includes a worm shaft as a driving shaft driven by a driving motor, a worm as a driving component provided on the worm shaft, and a worm wheel as a driven component mounted on the main shaft. Moreover, as is well known, the worm gear mechanism is a structure in which the worm wheel is directly meshed (engaged) with a worm groove formed in a spiral shape on the outer periphery of the worm.

[0005] Furthermore, in the drive transmission mechanism of the rotary indexing portion, the worm shaft is supported relative to the frame via a bearing, but the support at one end side thereof is performed via a ball bearing as a thrust bearing, and the support at the other end side is performed via a roller bearing as a radial bearing. That is, in the support of the drive shaft (worm shaft) of the above-mentioned drive transmission mechanism (worm gear mechanism), in order that the position of the driving component (worm) does not change in the axial direction of the driving shaft even if it is subjected to a reaction force from the driven component (worm wheel), a thrust bearing (ball bearing) capable of withstanding the load in the above-mentioned axial direction (thrust direction) is adopted for the support at one end side thereof.

[0006] Furthermore, in the multi-link rotary indexing device of Patent Document 1, the support by the thrust bearing on one end side is performed in the form of a bearing holder (bearing housing) containing the thrust bearing installed on the frame. In detail, in the drive transmission mechanism, the position of the driving component in the above-mentioned axial direction needs to be the desired position for proper engagement with the driven component. Therefore, when assembling the drive shaft of the driving component relative to the frame, it is necessary to assemble it in such a way that the position of the driving component in the above-mentioned axial direction becomes the desired position accompanied by position adjustment (alignment) of the driving shaft.

[0007] In addition, the radial bearing used for the support on the other end side is a bearing that specifically bears loads in the radial direction, so it is generally set in a state that allows displacement in the axial direction relative to the frame. In contrast, the thrust bearing used for the support on the one end side is a bearing that bears loads in the thrust direction in addition to loads in the radial direction, so it is set in a state that does not allow displacement in the above-mentioned axial direction relative to the frame (a state in which the position in the above-mentioned axial direction is fixed relative to the frame). Therefore, in a structure in which the thrust bearing is directly assembled to the frame, the position is fixed at the time of assembly, and the position of the drive shaft relative to the frame is also fixed, making it difficult to adjust the position in the above-mentioned axial direction during assembly.

[0008] Therefore, in the above-mentioned drive transmission mechanism, as described above, a thrust bearing is used as the support on one end side, and on this basis, the thrust bearing is generally set in the form of a bearing retainer with a built-in thrust bearing installed on a frame, so that the position of the drive shaft relative to the frame can be easily adjusted during assembly.

[0009] Moreover, in the existing multi-link rotary indexing device, each rotary indexing part is installed in the device in a form in which the direction of its driving shaft (the positional relationship of the above-mentioned one end side and the above-mentioned other end side of the driving shaft relative to the driving component in the above-mentioned axial direction) is the same. Therefore, two sets of adjacent rotary indexing parts in the above-mentioned axial direction are in a state in which the above-mentioned one end side of the driving shaft in the rotary indexing part on one side and the above-mentioned other end side of the driving shaft in the rotary indexing part on the other side are opposed to each other. On this basis, in such a multi-link rotary indexing device, the above-mentioned one end side of the driving shaft on one side and the above-mentioned other end side of the driving shaft on the other side, which are in an opposed state as described above, are connected by a connecting part, so that the driving shafts in each rotary indexing part are connected to each other.

[0010] Furthermore, in such a conventional multi-link rotary indexing device, generally speaking, the drive motor is provided in a form connected to the end of one of the drive shafts located on the outside in the axial direction in the state where the plurality of drive shafts are connected as described above, which is opposite to the connection (connection member) side. Furthermore, the drive motor is provided in such a connected form, thereby avoiding the enlargement of the rotary indexing device itself or the machine tool in which the rotary indexing device is provided in the conventional multi-link rotary indexing device.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2002-066877 Summary of the invention

[0014] Problems to be solved by the invention

[0015] However, in the above-mentioned conventional multi-stage rotary indexing device, the interval in the axial direction between two sets of rotary indexing parts adjacent in the axial direction becomes larger, and there is a problem that the rotary indexing device itself becomes larger.

[0016] As described above, in the existing multi-linked rotary indexing device, the two sets of adjacent rotary indexing parts in the above-mentioned axial direction are configured such that the above-mentioned one end side of the driving shaft in one rotary indexing part and the above-mentioned other end side of the driving shaft in the other rotary indexing part are connected to each other through a connecting member. Therefore, in this structure, of course, the connection position of the driving shafts of the two sets of rotary indexing parts exists between the two rotary indexing parts, and the thrust bearing supporting the above-mentioned one end side of the driving shaft in one rotary indexing part exists at a position on the driving member side (in the rotary indexing part) compared to the connection position.

[0017] In addition, as described above, the thrust bearing used for the support on the one end side is built into the bearing holder and is mounted on the frame via the bearing holder. In addition, generally speaking, the outer diameter of the thrust bearing is larger than the outer diameter of the radial bearing used for the support on the other end side. Therefore, the bearing holder in which the thrust bearing is built must also have a larger outer diameter. Therefore, in the structure of the multi-link rotary indexing device, the above-mentioned large-diameter bearing holder is present at a position on the drive shaft of each rotary indexing part.

[0018] Moreover, regarding the position of the bearing holder on the drive shaft, in each rotary indexing portion, a driven component having a larger outer diameter and in a disc shape is present in a form of meshing with a driving component provided on the drive shaft. Therefore, the position of the bearing holder having a larger diameter on the drive shaft interferes with the driven component at a position closer to the driving component, and thus has to be located away from the driving component so as not to cause such interference. That is, the drive shaft is supported at the one end side at a position farther from the driving component than at the other end side.

[0019] On this basis, the driving shaft in the above-mentioned one rotating indexing part is connected to the driving shaft in the adjacent other rotating indexing part at the above-mentioned one end side, but its connection position is of course closer to the outside (the side opposite to the driving component side) than the support position at the above-mentioned one end side, so that in the above-mentioned one rotating indexing part, the distance from the driving component to the connection position at the above-mentioned one end side is necessarily large. Moreover, as a result, in the existing multi-link rotating indexing device, the interval between the two rotating indexing parts becomes larger, and there is a problem that the entire device becomes large.

[0020] In view of the above problems, an object of the present invention is to provide a structure, that is, in the above-mentioned multi-link rotary indexing device, especially in the double-link rotary indexing device having two groups of rotary indexing parts, the interval between the two groups of rotary indexing parts can be reduced in the axial direction of the driving shaft, so that the overall device becomes compact.

[0021] Solutions to Solve Problems

[0022] The present invention is based on a double-linked rotary indexing device, which has two sets of rotary indexing parts, the rotary indexing part including a main shaft supported in a frame so as to be rotatable and having a rotating object part installed on one end side, and a driving transmission mechanism for transmitting the rotation of the output shaft of the driving motor to the main shaft, the driving transmission mechanism including a driving shaft driven by the driving motor, a disc-shaped driven part installed on the main shaft, and a driving part having a spiral groove directly or indirectly engaged with the driven part and arranged on the driving shaft, the driving shaft is supported by the frame on one side of one end via a bearing retainer with a thrust bearing installed therein, and is supported by the frame on one side of the other end via a radial bearing, the driving shafts of the two rotary indexing parts are connected by a connecting part, and the driving motor is connected to the end of the driving shaft on the side opposite to the connecting part side in one of the rotary indexing parts.

[0023] On this basis, the present invention is characterized in that the double rotary indexing device is configured such that the other end of the drive shaft in one rotary indexing portion is connected to the other end of the drive shaft in the other rotary indexing portion.

[0024] The effects of the invention are as follows.

[0025] According to the present invention, in the double-linked rotary indexing device based on the above premise, the double-linked rotary indexing device is configured such that the other end of the driving shaft in the rotary indexing part of one side is connected to the other end of the driving shaft in the rotary indexing part of the other side. As a result, each rotary indexing part is arranged in the device in a state where one side of the driving shaft supported by the thrust bearing becomes the outer side in the axial direction relative to the connection position connecting the two driving shafts. Therefore, in this structure, the bearing retainer provided to support the driving shaft in each rotary indexing part is provided at the above-mentioned outer side relative to each driving component, that is, it is in a form that exists at a position on the opposite side of the above-mentioned connection position side relative to the driving component. Moreover, the connection between the two rotary indexing parts is in a form that is carried out between the radial bearings supporting the above-mentioned other end side of each driving shaft.

[0026] In addition, since the outer diameter of the radial bearing is smaller than that of the thrust bearing and the bearing holder is not required in the setting as in the case of the thrust bearing, the position on the drive shaft can be made close to the drive component. Thus, compared with the above-mentioned existing structure, the structure can be made to make the above-mentioned connection position closer to the two drive components. Therefore, according to this structure, the interval between the two rotating indexing parts can be reduced in the above-mentioned axial direction, so that the device as a whole can be made small. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a top cross-sectional view showing a double rotary indexing device to which the present invention is applied.

[0028] Figure 2yes Figure 1 AA section view (side section view).

[0029] Figure 3 yes Figure 1 Enlarged view of the main part.

[0030] Explanation of symbols

[0031] 1-Double rotary indexing device, 2-Frame, 3-Drive motor, 5-Coupling (connecting component), 10-Rotation indexing part, 11-Spindle, 12-Workbench (rotation object component), 14-Bearing, 15-Clamping disk, 16-Clamping piston, 17-Pressure chamber, 18-Clamping device, 25-Storage hole, 25a-Storage part, 25b-Expansion part, 25c-Communication part, 25d-Embedding part, 26-Hole, 27-Motor bracket, 30-Vortex Worm-gear mechanism (drive transmission mechanism), 31—pinion, 32—driven gear, 33—drive shaft, 33a—one end, 33b—the other end, 34—worm (driving component), 35—worm wheel (driven component), 40—bearing retainer, 40a—main body, 40b—large diameter portion, 40d—through hole, 41—angular contact ball bearing (thrust bearing), 42a—inner threaded hole, 42b—stop screw, 43—roller bearing (radial bearing). DETAILED DESCRIPTION

[0032] Hereinafter, one embodiment (example) of a double rotary indexing device to which the present invention is applied will be described based on the drawings.

[0033] Figure 1 to Figure 3 A double rotary indexing device 1 to which the present invention is applied is shown. In addition, the double rotary indexing device 1 shown in the figure is a so-called horizontal double rotary indexing device in which the axis of the main shaft is arranged in the vertical direction. The double rotary indexing device 1 includes a frame 2 mounted on a machine tool, two sets of rotary indexing parts 10, 10 arranged in the frame 2, and a driving motor 3 for rotating and driving each rotary indexing part 10. In addition, the two sets of rotary indexing parts 10, 10 have basically the same structure. Therefore, hereinafter, only one of the two sets of rotary indexing parts 10, 10 will be described, and the description of the other will be omitted.

[0034] like Figure 2 and Figure 3 As shown, the rotary indexing unit 10 includes a spindle 11 supported in a space within the frame 2 so as to be rotatable relative to the frame 2 and a table 12 as a rotating object component mounted on one end side of the spindle 11. In addition, the rotary indexing unit 10 includes a drive transmission mechanism 30 for transmitting the rotation of the output shaft of the drive motor 3 to the spindle 11 and a clamping device 18 for holding (clamping) the spindle 11 at the indexed angular position.

[0035] More specifically, the spindle 11 is supported by the bearing 14 in a space within the frame 2 with its axis oriented in the vertical direction so as to be rotatable relative to the frame 2. The table 12 is a disc-shaped component for mounting a workpiece or the like to be processed, and is mounted at one end of the spindle 11 by a plurality of mounting bolts (not shown) in a state where its end surface abuts against the spindle 11 so as to be non-rotatable relative to the spindle 11.

[0036] In addition, regarding the drive transmission mechanism 30, the present embodiment adopts a so-called worm gear mechanism including a disc-shaped worm wheel and a worm directly engaged with the worm wheel as an example of the drive transmission mechanism 30. Regarding the worm gear mechanism (drive transmission mechanism) 30, in more detail, the worm gear mechanism 30 is composed of a drive shaft 33 driven by the drive motor 3, a disc-shaped worm wheel 35 as a driven member mounted on the main shaft 11, and a worm 34 as a driving member provided on the drive shaft 33.

[0037] The worm wheel 35 is installed in the above-mentioned space of the frame 2 so as to be non-rotatable relative to the main shaft 11. In addition, the worm wheel 35 is composed of a shaft-shaped shaft portion installed on the main shaft 11 and a flange-shaped portion protruding in the radial direction from the shaft portion, that is, a flange portion having helical teeth formed on the outer peripheral surface. Moreover, the worm wheel 35 is set so that the flange portion is located approximately in the center of the main shaft 11 in the axial direction of the main shaft 11.

[0038] Furthermore, the drive shaft 33 is arranged in the frame 2 in such a manner that the axis thereof is oriented in the horizontal direction (a direction orthogonal to the axis of the main shaft 11). Therefore, a hole for accommodating the drive shaft 33, namely a receiving hole 25, is provided in the frame 2. The receiving hole 25 is formed to be connected to the above-mentioned space and to penetrate the frame 25 in the horizontal direction. In addition, the receiving hole 25 is formed to be a hole having a larger hole diameter than the thickness dimension of the above-mentioned flange portion of the worm wheel 35. Moreover, the receiving hole 25 is formed at a position including the existence range of the above-mentioned flange portion in the axial direction of the main shaft 11. Moreover, the drive shaft 33 is supported in the receiving hole 25 via a bearing so as to be rotatable relative to the frame 2.

[0039] On this basis, a worm 34 is provided on the drive shaft 33 supported in the storage hole 25 as described above. In addition, the worm 34 is provided at a substantially central portion of the drive shaft 33. Moreover, as is well known, the worm 34 is a gear having spiral teeth formed on the outer periphery, and having a spiral groove formed by the teeth on the outer peripheral surface. Moreover, when the worm 34 is provided on the drive shaft 33 as described above, the groove is in a state of meshing with the helical teeth of the flange portion of the worm wheel 35.

[0040] Moreover, in the present embodiment, the worm 34 is a so-called multi-lead worm in which the lead is slightly different on the left and right sides of the tooth surface and the thickness dimension of the tooth gradually increases toward one side in the axial direction of the drive shaft 33. And, as is well known, the worm gear mechanism 30 including such a multi-lead worm 34 adjusts the backlash between the worm 34 and the flange portion of the worm wheel 35 by displacing the worm 34 in the axial direction of the drive shaft 33.

[0041] Furthermore, in the double rotary indexing device 1 in which the rotary indexing part 10 has the above structure, the two sets of rotary indexing parts 10, 10 are arranged in the frame 2 in a configuration in which the axes of the two drive shafts 33, 33 are aligned when viewed along the axial direction thereof. On this basis, the end of the drive shaft 33 in one rotary indexing part 10 is connected to the end of the drive shaft 33 in the other rotary indexing part 10 by a coupling 5 as a connecting member.

[0042] Furthermore, the drive motor 3 for driving the drive shafts 33, 33 is connected to the connected drive shafts 33, 33. In more detail, the frame 2 is provided with a hole 26 which is a bottomed hole opened on one of the two side surfaces where the storage hole 25 opens, and the hole 26 is used to accommodate the output shaft of the drive motor 3. Furthermore, the hole 26 is formed so as to be located above the storage hole 25 when viewed along the axial direction of the drive shaft 33, and a portion thereof overlaps with the storage hole 25. Furthermore, a plate-shaped motor bracket 27 is mounted on the side surface of the above-mentioned one side of the frame 2 in the form of blocking the opening of the storage hole 25 and the opening of the hole 26. Furthermore, a through hole is provided through the motor bracket 27 at a position communicating with the hole 26.

[0043] On this basis, the drive motor 3 is mounted on the motor bracket 27 in a form in which the output shaft passes through the through hole of the motor bracket 27 and is accommodated in the hole 26. In addition, a pinion 31 is mounted on the output shaft of the drive motor 3. On the other hand, a driven gear 32 meshing with the pinion 31 is mounted on the drive shaft 33 on the drive motor 3 side of the two drive shafts 33, 33 connected as described above and at the end on the side opposite to the coupling 5 (connecting member) side (drive motor 3 side). As a result, the two drive shafts 33, 33 are in a state where the end on the side opposite to the connecting member side of the drive shaft 33 in the rotation indexing portion 10 on one side (drive motor 3 side) is connected to the drive motor 3 via the driven gear 32 and the pinion 31.

[0044] Moreover, as described above, each rotary indexing portion 10 is provided with a clamping device 18 for holding the main spindle 11 at an angular position indexed as a result of the two drive shafts 33, 33 being rotationally driven by the connected drive motor 3. In addition, in the illustrated example, the clamping device 18 is a so-called disc-type clamping device. Specifically, the clamping device 18 includes a clamping disk 15 mounted on the side of the main spindle 11 and a clamping piston 16 that presses the clamping disk 15 toward a clamping surface provided on the frame 2, and a working fluid is supplied to a pressure chamber 17 divided by the clamping piston 16 and the frame 2, and the clamping disk 15 is clamped by the clamping piston 17 and the clamping surface using the pressure of the working fluid, thereby achieving a state (clamped state) in which the main spindle 11 is held.

[0045] In the double rotary indexing device 1 described above, in the present invention, the driving shaft 33 of each rotary indexing part 10 is supported by the frame 2 via a thrust bearing on one side of one end thereof, and is supported by the frame 2 via a radial bearing on one side of the other end thereof. Among them, the thrust bearing supporting the driving shaft 33 on one side of one end thereof is provided in the form of being built into a bearing holder, and is mounted on the frame 2 via the bearing holder. On this basis, in the present invention, the double rotary indexing device 1 is configured such that two rotary indexing parts 10, 10 are arranged in the form of connecting the other end of the driving shaft 33 in the rotary indexing part 10 on one side with the other end of the driving shaft 33 in the rotary indexing part 10 on the other side. Hereinafter, an embodiment (example) of such a double rotary indexing device 1 will be described in detail.

[0046] In the double rotary indexing device 1, each rotary indexing portion 10 is configured such that its drive shaft 33 is supported by the frame 2 via the thrust bearing 41 on one end 33a thereof as described above, and is supported by the frame 2 via the radial bearing 43 on the other end 33b thereof. In the present embodiment, the thrust bearing 41 is an angular contact ball bearing, and the radial bearing 43 is a roller bearing.

[0047] Furthermore, in the double rotary indexing device 1, as described above, the two rotary indexing parts 10, 10 are provided in a form in which the end portion on the other end 33b side of the driving shaft 33 in one rotary indexing part 10 is connected to the end portion on the other end 33b side of the driving shaft 33 in the other rotary indexing part 10. Figure 1 The rotation indexing portion 10 of the right side in the figure is configured such that one end 33a of the drive shaft 33 is one of the two side surfaces where the storage hole 25 in the frame 2 opens (the drive motor 3 side), and the other end 33a of the drive shaft 33 is one of the two side surfaces where the storage hole 25 in the frame 2 opens (the drive motor 3 side). Figure 1 The rotation indexing portion 10 (on the left side in the figure) is constructed so that one end 33a side of the driving shaft 33 becomes the other side of the above-mentioned two side surfaces (the side opposite to the driving motor 3 side).

[0048] Therefore, in each rotary indexing portion 10, the position of the angular contact ball bearing 41 supporting the end portion on the side of one end 33a of the drive shaft 33 becomes the corresponding end portion in the receiving hole 25 of the frame 2. On this basis, at the end portion of the receiving hole 25, the angular contact ball bearing 41 supporting the drive shaft 33 is installed in the bearing holder 40 and is installed on the frame 2 via the bearing holder 40. That is, each drive shaft 33 is supported by the frame 2 at the end portion of the receiving hole 25 via the bearing holder 40 in which the angular contact ball bearing 41 is installed.

[0049] Each bearing holder 40 is a hollow cylindrical member having a through hole 40d in the center for housing an angular contact ball bearing 41. The bearing holder 40 is formed so that the outer diameter of a portion on one end side in the axial direction is larger than the outer diameter of the other portion. That is, the bearing holder 40 is composed of the large diameter portion 40b on the one end side and the main body portion 40a other than the large diameter portion 40b.

[0050] In contrast, the receiving hole 25 is formed to have an expanded diameter portion 25b at both ends thereof whose aperture is larger than the aperture of the other portion. Furthermore, in the receiving hole 25, a portion (communication portion) 25c communicating between the portion (storage portion) 25a for storing the worm 34 and the expanded diameter portion 25b and the two portions needs to have an aperture larger than the outer diameter of the worm 34 so that the worm 34 can be inserted from the outside toward the receiving portion 25a. In the illustrated example, the aperture is the same as the aperture of the receiving portion 25a.

[0051] On this basis, the large diameter portion 40b in the bearing holder 40 is formed so that its outer diameter is substantially the same as the hole diameter of the enlarged diameter portion 25b in the receiving hole 25. Furthermore, the main body portion 40a is formed so that its outer diameter is substantially the same as the hole diameter of the connecting portion 25c in the receiving hole 25. Furthermore, each bearing holder 40 is provided in a form in which the main body portion 40a is inserted into the connecting portion 25c with respect to the corresponding end portion in the receiving hole 25 in a direction in which the large diameter portion 40b side becomes the opening side (outside) of the receiving hole 25.

[0052] In addition, an internal thread is formed on the inner circumferential surface of each enlarged diameter portion 25b in the storage hole 25, and on the other hand, an external thread is formed on the outer circumferential surface of the large diameter portion 40b in each bearing holder 40. Thus, each bearing holder 40 is mounted on the frame 2 in a form in which the external thread of its large diameter portion 40b is threadedly engaged with the internal thread of the enlarged diameter portion 25b of the storage hole 25. And, according to this structure, by rotating the bearing holder 40 (external thread of the large diameter portion 40b) relative to the frame 2 (internal thread of the enlarged diameter portion 25b), the position of the bearing holder 40 relative to the frame 2 can be changed in the axial direction of the drive shaft 33.

[0053] On this basis, the frame 2 is formed with internal threaded holes 42a which are opened in the communication parts 25c in the storage hole 25 and are penetrated in a horizontal direction from the rear surface of the frame 2 toward the storage hole 25. In addition, a stop screw 42b is threadedly inserted into each of the internal threaded holes 42a. In addition, the position of each bearing holder 40 relative to the frame 2 is fixed by pressing each stop screw 42b onto the outer peripheral surface of the main body 40a in the bearing holder 40 inserted into the communication part 25c as described above.

[0054] In addition, each bearing holder 40 mounted on the frame 2 as described above has an angular contact ball bearing 41 therein, and in the example shown in the figure, two angular contact ball bearings 41 are provided in the through hole 40d. In each through hole 40d, two angular contact ball bearings 41, 41 are provided at a distance in a direction facing each other.

[0055] The roller bearing 43 used for supporting the other end 33b of the drive shaft 33 is a bearing that is specifically designed to bear radial loads. Therefore, the roller bearing 43 is directly embedded in the receiving hole 25 on the other end 33b and is provided in a state that allows displacement in the axial direction.

[0056] Furthermore, as described above, the bearing holder 40 in which the angular contact ball bearing 41 supporting the one end 33a side of the drive shaft 33 is installed is arranged in a state that it can be displaced relative to the frame 2 in the axial direction of the drive shaft 33. In addition, the roller bearing 43 supporting the other end 33b side of the drive shaft 33 is arranged in a state that allows displacement in the axial direction thereof. Thus, in the worm gear mechanism 30 using the above-mentioned multi-lead worm 34, by displacing the bearing holder 40 relative to the frame 2 in the axial direction of the drive shaft 33, the worm 34 can be displaced relative to the worm wheel 35 in the axial direction of the drive shaft 33 to adjust the above-mentioned backlash.

[0057] Furthermore, as described above, the worm 34 stored in the storage hole 25 (storage portion 25a) is configured to mesh with the worm wheel 35 provided in the above-mentioned space of the frame 2, and the storage hole 25 is formed so that its storage portion 25a is connected to the above-mentioned space. Moreover, this connection is achieved by forming an opening formed in the storage portion 25a throughout the axial direction of the drive shaft 33. As a result, in the storage hole 25, a part of its storage portion 25a overlaps with a part of the above-mentioned space in the axial direction of the drive shaft 33, and a part of the disc-shaped worm wheel 35 penetrates into the storage portion 25a in the radial direction through the above-mentioned opening.

[0058] On this basis, the roller bearing 43 is provided in the receiving hole 25 and in a portion (embedded portion) 25d on the opposite side of the communicating portion 25c relative to the receiving portion 25a thereof in a form directly inserted into the receiving hole 25 (embedded portion 25d) as described above. However, the outer diameter of the roller bearing 43 is generally smaller than the outer diameter of the angular contact ball bearing 41 used for supporting the one end 33a side of the above-mentioned drive shaft 33. Therefore, the embedding portion 25d in the receiving hole 25 is formed to have a smaller hole diameter than the hole diameters of the receiving portion 25a and the communicating portion 25c.

[0059] In addition, the embedding portion 25d and the communicating portion 25c are portions that are continuous (communicated) with the receiving portion 25a on both sides of the receiving portion 25a as described above. Furthermore, the embedding portion 25d is formed so that its aperture is smaller than the aperture of the communicating portion 25c. Therefore, in the relationship between the embedding portion 25d and the worm wheel 35 that intrudes into the receiving portion 25a as described above, the embedding portion 25d can be formed at a position closer to the worm 34 than the communicating portion 25c.

[0060] Therefore, in the rotation indexing portion 10, the insertion portion 25d is formed at a position closer to the worm 34 than the connecting portion 25c. As a result, the position of the roller bearing 43 disposed in the insertion portion 25d, that is, the support position of the roller bearing 43 on the other end 33b side of the drive shaft 33 is closer to the worm 34 than the support position of the angular contact ball bearing 41 on the one end 33a side of the drive shaft 33.

[0061] Thus, in the two rotary indexing parts 10, 10 of the double rotary indexing device 1, the drive shaft 33 is provided in such a manner that the other end 33b side based on the roller bearing 43 is supported at a position closer to the worm 34 than the one end 33a side based on the angular contact ball bearing 41 (bearing holder 40). And, concomitantly, the drive shaft 33 in each rotary indexing part 10 is formed such that the distance from the worm 34 to the shaft end on the drive shaft 33 is shorter on the other end 33b side than on the one end 33a side.

[0062] On this basis, as described above, the double-linked rotary indexing device 1 is configured such that the other end 33b side of the drive shaft 33 in one rotary indexing portion 10 is connected to the other end 33b side of the drive shaft 33 in the other rotary indexing portion 10. Therefore, according to this structure, for example, compared with a double-linked rotary indexing device in which the drive shaft 33 in one rotary indexing portion 10 is connected at its one end 33a side to the drive shaft 33 (other end 33b) in the other rotary indexing portion 10, the distance from the position of the worm 34 in the rotary indexing portion 10 on the one side to the connection position of the two drive shafts 33, 33 is shorter.

[0063] In addition, in the rotary indexing part 10, the position of the worm 34 corresponds to the position of the main shaft 11 in the axial direction of the drive shaft 33, so as described above, the distance from the position of the worm 34 in one rotary indexing part 10 to the connection position of the two drive shafts 33, 33 becomes shorter, thereby reducing the interval between the two main shafts 11, 11 in the double rotary indexing device 1. Therefore, according to such a structure, the interval between the two rotary indexing parts 10, 10 can be minimized in the axial direction of the drive shaft 33, so that the whole double rotary indexing device 1 can be made small.

[0064] An embodiment of the double rotary indexing device of the present invention has been described above, but the double rotary indexing device of the present invention is not limited to the above embodiment, and can also be implemented in the following modified examples.

[0065] (1) Regarding the drive transmission mechanism, in the above embodiment, a worm gear mechanism 30 composed of a worm wheel 35 and a worm 34 is used as a drive transmission mechanism for transmitting the rotation of the output shaft of the drive motor 3 to the main shaft 11. In addition, in the above embodiment, the worm 34 in the worm gear mechanism 30 is a multi-lead worm.

[0066] However, in the present invention, even when a worm gear mechanism is used as a drive transmission mechanism, the worm is not limited to the multi-lead worm of the above-mentioned embodiment, but may be a so-called single-lead worm formed so that the thickness dimension of the teeth is constant in the axial direction of the drive shaft 33. In addition, in the case where the worm is a single-lead worm, even if the worm is displaced in the axial direction of the drive shaft 33, the tooth gap between the worm and the worm wheel cannot be adjusted, so that the double-linked rotary indexing device may not be configured so that the drive shaft can adjust its position in the axial direction as in the above-mentioned embodiment. Therefore, in this case, the bearing retainer may also be configured so that the position in the axial direction of the drive shaft cannot be changed. That is, the double-linked rotary indexing device may also be configured so that the bearing retainer is set in a form fixed to a specific position.

[0067] Furthermore, the drive transmission mechanism is not limited to the worm gear mechanism as the above-mentioned embodiment in which the worm as the driving component directly engages with the worm wheel as the driven component in a spiral groove, but may also be other forms of drive transmission mechanisms in which the driving component indirectly engages with the driven component in a spiral groove. Specifically, the drive transmission mechanism may also be a so-called ball drive mechanism in which the worm wheel and the worm are connected via steel balls. Furthermore, the drive transmission mechanism may also be a so-called roller wheel cam mechanism in which a turret wheel having a plurality of roller followers installed at intervals on the periphery and a roller wheel cam having a spiral cam groove corresponding to the roller of the roller follower are connected. In addition, in the case of the roller wheel cam mechanism, the turret wheel is equivalent to the driven component, and the roller wheel cam is equivalent to the driving component.

[0068] (2) Regarding the frame of the double rotary indexing device, in the above embodiment, the double rotary indexing device 1 is constructed so that the frame 2 on which the two groups of rotary indexing parts 10, 10 are arranged is an integrally formed component. However, the double rotary indexing device is not limited to being constructed so that the frame is formed like this, and can also be constructed so that two components that are respectively arranged with two groups of rotary indexing parts are combined (connected) to form a frame. In addition, in this case, each component used to form the frame forms a through hole that becomes a storage hole when combined, and one of the side surfaces (the surface where the through hole opens) of the two components becomes a connecting surface that is orthogonal to the through direction of the storage hole (parallel to the axis of the main shaft). On this basis, the two components are combined in a state where their connecting surfaces are abutted to form a frame.

[0069] (3) Regarding the double rotary indexing device which is the premise of the present invention, in the above-mentioned embodiment, the double rotary indexing device 1 is a so-called horizontal double rotary indexing device in which the axis of its main shaft is arranged in the vertical direction. However, the double rotary indexing device to which the present invention is applied is not limited to such a horizontal double rotary indexing device, but may also be a so-called vertical double rotary indexing device in which the axis of the main shaft is arranged in the horizontal direction. Furthermore, the double rotary indexing device to which the present invention is applied is not limited to being arranged in the form of being directly mounted on a machine tool in the above-mentioned frame. For example, the present invention may also be applied to the rotary indexing part of a so-called inclined rotary indexing device having two types of rotary indexing parts, an inclined indexing part and a rotary indexing part.

[0070] In addition, the present invention is not limited to any of the above-described embodiments, and can be modified appropriately within the scope of the present invention.

Claims

1. A double-linked rotary indexing device, comprising two sets of rotary indexing parts, the rotary indexing part including a main shaft which is supported in a frame so as to be rotatable and has a rotating object part installed on one end side, and a drive transmission mechanism which transmits the rotation of the output shaft of the driving motor to the main shaft, the drive transmission mechanism including a driving shaft which is rotationally driven by the driving motor, a disc-shaped driven part installed on the main shaft, and a driving part which has a spiral groove and is directly or indirectly engaged with the driven part and is arranged on the driving shaft, the driving shaft is supported by the frame on one side of one end via a bearing holder which has a thrust bearing installed therein, and is supported by the frame on one side of the other end via a radial bearing, the driving shafts of the two rotary indexing parts are connected by a connecting member, the driving motor is connected to the end of the driving shaft on the side opposite to the connecting member side in one rotary indexing part, and the double-linked rotary indexing device is characterized in that, The other end of the drive shaft in the one rotation indexing portion is coupled to the other end of the drive shaft in the other rotation indexing portion.

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