Machine tool including a rotary cutting device

Abstract

To provide a machine tool which enables an operator to easily manage an oil amount in a storage part of a rotation indexing device.SOLUTION: The machine tool comprises rotation indexing device 3, 4 for indexing an angle position of a rotation target member fitted to an end of a rotary shaft. The rotation indexing device includes: frames 5, 6 for storing the rotary shaft in the state of being rotatably supported; a drive motor 21 for rotary-driving the rotary shaft; and a drive transmission mechanism stored in a space inside the frames to transmit rotation of an output shaft of the drive motor to the rotary shaft. The drive transmission mechanism includes a gear mechanism. The space includes one or more storage parts for storing lubricating oil for lubricating at least the gear mechanism. The rotation indexing device includes a detection device for detecting a height position of an oil surface of the lubricating oil stored in the storage parts. The detection device is provided in a detection target storage part set as a detection target among the one or more storage parts on a one-to-one basis.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a machine tool including a rotation detection device for determining the angular position of a rotatable member attached to an end of a rotation axis, wherein the rotation detection device includes a frame that rotatably supports the rotation axis and houses it, a drive motor that rotationally drives the rotation axis, and a drive transmission mechanism that is housed in a space inside the frame and transmits the rotation of the output shaft of the drive motor to the rotation axis, and the drive transmission mechanism Composed of a plurality of gears that mesh with each other includes a gear mechanism, and the space Corresponding to the gear mechanism and contains lubricating oil for lubricating the gear mechanism is stored and one or more storage parts a storage portion partitioned by a sealing member from other portions in the space and relates to a machine tool.

Background Art

[0002] As a machine tool including the above-described rotation detection device, there is one described in Patent Document 1. The machine tool disclosed in Patent Document 1 includes an NC circular table device (rotation detection device) having a rotation table configured to be able to attach a workpiece. In the rotation detection device, the frame is formed as a housing having a space inside. And in the space in the frame (housing), a rotation axis with a table attached to one end is housed. Further, a drive motor (servo motor) for rotationally driving the rotation axis (rotation table) is attached to the frame. Furthermore, the drive motor and the rotation axis are connected via a drive transmission mechanism that transmits the rotation of the drive motor to the rotation axis, and the drive transmission mechanism is also housed in the space in the frame described above.

[0003] Note that the drive transmission mechanism includes a gear mechanism such as a worm and a worm wheel. And lubricating oil is stored in a portion corresponding to the gear mechanism in the space so as to lubricate the gear mechanism. In other words, the space includes a storage part in which lubricating oil for lubricating the gear mechanism is stored.

[0004] In such a machine tool, the amount of lubricating oil (oil quantity) in the reservoir of the rotary indexing device may change. Specifically, in the reservoir, the oil quantity may decrease due to leakage or the like, or coolant may infiltrate and the oil quantity may increase. When the oil quantity decreases, the gear mechanism is in a state of insufficient lubrication. Also, when the oil quantity increases, the lubricating oil is in a state where the lubricating performance deteriorates due to the mixing of the coolant that has infiltrated into the reservoir. And in either case, as the gear mechanism wears with operation, the accuracy of the angular position of the workpiece indexed by the rotary indexing device decreases.

[0005] Therefore, in such a machine tool, an operator needs to manage the oil quantity. Thus, a general rotary indexing device is provided with a direct-vision oil gauge as a configuration for managing the oil quantity, so that the operator can visually confirm the height position of the oil level in the reservoir. Incidentally, the oil gauge is provided at a position corresponding to the reservoir in the frame so that it can be confirmed from the outside.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, in a machine tool including a conventional rotary indexing device, the rotary indexing device is provided in the machining area of the machine tool where the workpiece is machined. Therefore, the rotary indexing device is often in a state where dirt adheres to its surface due to coolant and cutting chips that scatter into the machining area during the machining of the workpiece.

[0008] In such a case, in the case of an oil gauge provided with a configuration for managing (checking) the oil quantity as described above, due to dirt adhering to the surface of the rotation detection device as described above, it may not be possible to check the oil quantity (the height position of the oil level) as it is. And when the oil quantity cannot be checked due to such dirt, in order to check it, an operator needs to perform a cleaning operation to remove the adhering dirt around the oil gauge.

[0009] As described above, a machine tool including a conventional rotation detection device manages the oil quantity by checking the oil quantity using an oil gauge that may involve the above-described cleaning operation, and there has been a problem that a large burden may be imposed on the operator in such management.

[0010] The present invention has been created in consideration of the above circumstances, and an object thereof is to provide a machine tool including a rotation detection device capable of reducing the burden on an operator in managing the oil quantity in the storage portion as described above.

Means for Solving the Problem

[0011] The present invention is a machine tool including a rotation detection device for determining the angular position of a rotation target member attached to an end of a rotation shaft. In particular, the rotation detection device includes a frame that houses the rotation shaft in a rotatable state, a drive motor that rotationally drives the rotation shaft, and a drive transmission mechanism that is housed in the space inside the frame and transmits the rotation of the output shaft of the drive motor to the rotation shaft. The drive transmission mechanism Composed of a plurality of gears that mesh with each other includes a gear mechanism, and the space Corresponding to the gear mechanism and is lubricating oil for lubricating the gear mechanism is stored one or more storage portions a storage portion partitioned by a sealing member from other portions in the space is premised on a machine tool including.

[0012] Furthermore, the present invention includes a detection device for detecting the height position of the oil level of the lubricating oil stored in the storage portion, and the detection device is provided one-to-one for a detection target storage portion set as a detection target among one or more of the storage portions.

[0013] Further, the machine tool according to such an invention may include a display device that is connected to the detection device and displays information regarding the height position detected by the detection device.

[0014] Further, the display device may be provided outside the cover that covers the processing area where the rotation detection device is disposed and the workpiece is processed.

Advantages of the Invention

[0015] According to the present invention, in a machine tool including the rotation detection device on the premise as described above, a detection device is provided in a one-to-one manner with respect to the detection target storage portion in the rotation detection device to detect the height position of the oil level in the detection target storage portion. Thereby, by setting the storage portion that requires management of the oil quantity as the detection target storage portion, the management of the oil quantity in the detection target storage portion can be performed using the detection result regarding the height position of the oil level by the detection device. Therefore, according to the present invention, by doing as described above, compared with a machine tool including a conventional rotation detection device in which the management of the oil quantity is performed using an oil gauge, the burden for the cleaning work as described above can be prevented from being imposed on the operator, and the burden imposed on the operator in the management of the oil quantity can be reduced.

[0016] Further, in the machine tool according to the present invention, by providing a display device that displays information regarding the height position of the oil level detected by the detection device, the operator can visually confirm the information displayed on the display device, and the operator can grasp the information regarding the height position of the oil level. Thereby, since the management of the oil quantity is performed while the operator grasps the state of the oil quantity, more appropriate management of the oil quantity can be performed.

[0017] Furthermore, in the machine tool according to the present invention, with respect to a cover that covers a machining area where the rotation indexing device is disposed and machining of a workpiece is performed, the display device is provided outside the cover. As a result, visual confirmation of the display device can be performed outside the cover. Therefore, confirmation of the information (display) regarding the oil amount as described above for the management of the oil amount can be performed more easily.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0019] Hereinafter, based on FIGS. 1 to 6, an embodiment (example) of the machine tool 1 to which the present invention is applied will be described. As shown in FIG. 1, the machine tool 1 of this embodiment is a machine tool 1 (so-called horizontal machining center) in which the direction of the rotation axis of the main shaft 1a is parallel to the horizontal direction. Further, the machine tool 1 includes a bed 1b serving as a base, a column 1c supported so as to be movable in the horizontal direction (X-axis direction) with respect to the bed 1b, a spindle head 1d supported so as to be movable in the vertical direction (Y-axis direction) with respect to the column 1c, and a table 1e provided on the bed 1b so as to be movable in a direction (Z-axis direction) orthogonal to the X-axis direction and the Y-axis direction. Note that the machine tool 1 of this embodiment includes a box-shaped exterior cover 1f. The exterior cover 1f is attached to the bed 1b so as to cover the area above the bed 1b including the machining area where the workpiece is machined in the machine tool 1.

[0020] Further, the machine tool 1 includes an inclined circular table device 2 for determining the angular position of the workpiece. More specifically, as shown in FIG. 2, the machine tool 1 of this embodiment includes a rotation detection device (tilt drive unit) 3 for determining the angular position of the rotary table 7 on which the workpiece is placed around the horizontal axis L1, and a rotation detection device (rotation drive unit) 4 for determining the angular position of the rotary table 7 on which the workpiece is placed around the axis L2 of the support shaft 17 that supports the rotary table 7. The machine tool 1 includes an inclined circular table device 2 including two types of rotation detection devices 3 and 4.

[0021] The inclined circular table device 2 is provided on the table 1e of the machine tool 1. The inclined circular table device 2 includes a base frame 5 placed on the table 1e of the machine tool 1, an inclined frame 6 supported by the base frame 5, and a rotary table 7 installed on the inclined frame 6 and on which the workpiece is placed. The base frame 5 and the inclined frame 6 are frames in the inclined circular table device 2 including the two types of rotation detection devices 3 and 4 of this embodiment, and correspond to the frames in the present invention.

[0022] The base frame 5 is composed of a plate-shaped pedestal 5a serving as a base, and a pair of support bases 5b and 5c erected on the pedestal 5a at intervals in the longitudinal direction of the pedestal 5a. Further, as shown in FIGS. 4 and 5, in the base frame 5, rotation shafts 8 and 9 are rotatably supported on the respective support bases 5b and 5c of the pair via bearings B1 and B2.

[0023] Further, as shown in FIG. 2, the inclined frame 6 is a so-called cradle-type support frame, and is composed of an inclined table 14 on which the rotary table 7 is installed, and a pair of arm portions 15 and 16 for supporting the inclined table 14.

[0024] Note that, as shown in FIGS. 4 and 5, the inclined table 14 is formed in a housing shape that is externally plate-shaped and rectangular when viewed in the plate thickness direction, and has a space inside. And the inclined frame 6 is supported on the base frame 5 via a pair of rotation shafts 8 and 9 by fixing the respective arm portions 15 and 16 to the corresponding rotation shafts 8 and 9 between the pair of support bases 5b and 5c (between the pair of rotation shafts 8 and 9) in the base frame 5.

[0025] Further, a support shaft 17 is provided on the inclined table 14 in the inclined frame 6 in a direction in which the direction of the axis L2 coincides with the plate thickness direction of the inclined table 14. More specifically, a housing hole (hereinafter, also referred to as "support shaft housing hole") 14a for housing the support shaft 17 is formed at the center of the inclined table 14. And the support shaft 17 is housed in the support shaft housing hole 14a in a direction in which the direction of the axis L2 coincides with the plate thickness direction. However, the support shaft 17 is arranged such that one end portion thereof protrudes from the upper surface of the inclined table 14 with respect to the plate thickness direction, and is rotatably supported on the inclined table 14 via a bearing B3.

[0026] In addition, a disk-shaped back cover 19 is provided in the accommodation hole 14a for the support shaft on the side opposite to the side where the support shaft 17 protrudes in the plate thickness direction. A through hole 19a is formed in the substantially center of the disk shape of the back cover 19. Further, the through hole 19a is a hole whose inner diameter is larger than the outer diameter of the other end portion of the support shaft 17. And the back cover 19 is attached to the inclined table 14 in such a manner that the other end portion of the support shaft 17 is inserted into the through hole 19a.

[0027] And a rotary table 7 is attached to one end of the support shaft 17. The rotary table 7 is a disk-shaped member and is provided with its center aligned with the axis L2 of the support shaft 17. And by being attached to the support shaft 17 in such a manner, the rotary table 7 is supported rotatably with respect to the inclined table 14.

[0028] Then, as shown in FIG. 2, the inclined circular table device 2 includes an inclination drive unit 3 for swing-driving the inclined frame 6 and a rotation drive unit 4 for rotationally driving the rotary table 7.

[0029] The inclination drive unit 3 is provided in one of the pair of support bases 5b and 5c in the base frame 5 (hereinafter also referred to as the "drive support base") 5b so as to rotationally drive a rotary shaft (hereinafter also referred to as the "inclination drive shaft") 8 that is rotatably supported within the drive support base 5b. Therefore, the inclination drive unit 3 includes an inclination drive motor 21 as a drive source for rotationally driving the inclination drive shaft 8. And the inclination drive motor 21 of the present embodiment corresponds to the drive motor in the present invention.

[0030] In addition, the tilt drive shaft 8 that is rotationally driven by the tilt drive motor 21 supports a tilt frame 6 whose angular position is determined by the tilt drive unit 3. Therefore, the tilt drive shaft 8 and the drive support base 5b to which the tilt drive motor 21 is attached and which supports the tilt drive shaft 8 also form part of the tilt drive unit 3. For the tilt drive unit 3, the tilt frame 6 that is attached to the tilt drive shaft 8 and whose angular position is determined around the axis L1 of the tilt drive shaft 8 corresponds to the rotation target member 6 in the rotation detection device 3.

[0031] Regarding the tilt drive unit 3 in detail, as shown in FIGS. 3 and 4, the drive support base 5b includes a frame main body portion 22 that is a main portion where the tilt drive shaft 8 is rotatably supported, and a motor attachment portion 23 where the tilt drive motor 21, which is a drive source, is attached.

[0032] More specifically, for the drive support base 5b, the frame main body portion 22 is externally substantially rectangular parallelepiped-shaped. The tilt drive shaft 8 is provided with respect to the frame main body portion 22 in such a manner as to span both side surfaces in the thickness direction (X-axis direction) of the frame main body portion 22. Therefore, the frame main body portion 22 has a housing hole (hereinafter also referred to as the "housing hole for tilt shaft") 22a formed so as to penetrate in the thickness direction as a space for housing the tilt drive shaft 8 in such a manner. The tilt drive shaft 8 is supported with respect to the frame main body portion 22 via a bearing B1 in such an arrangement that one end portion thereof slightly protrudes from the frame main body portion 22.

[0033] Note that a disk-shaped rear cover 24 is provided in the housing hole 22a for tilt shaft on the side opposite to the side where the tilt drive shaft 8 protrudes in the thickness direction. A through hole 24a is formed in the substantially center of the disk shape of the rear cover 24. The through hole 24a is a hole whose inner diameter is larger than the outer diameter of the other end portion of the tilt drive shaft 8. The rear cover 24 is attached to the frame main body portion 22 in such a manner that the other end portion of the tilt drive shaft 8 is inserted into the through hole 24a.

[0034] Further, as shown in FIG. 3, the motor mounting portion 23 is also formed to have a substantially rectangular parallelepiped shape in appearance, and protrudes from the front side surface 22r of the front and rear surfaces (substantially orthogonal to the both side surfaces) parallel to the thickness direction in the frame main body portion 22, and is integrally formed with the frame main body portion 22. The motor mounting portion 23 is formed in a housing shape having a space (hereinafter also referred to as "internal space") 23a inside. However, the height dimension of the motor mounting portion 23 is smaller than the height dimension of the frame main body portion 22, and is about 1 / 4 in the illustrated example.

[0035] Then, the tilt drive motor 21 is mounted on the upper surface of the motor mounting portion 23 with its output shaft 21a directed downward. Therefore, the tilt drive motor 21 is mounted on the motor mounting portion 23 in such a state that the tip of its output shaft 21a enters the internal space 23a. For this reason, a through hole 23c through which the output shaft 21a penetrates is formed in the upper wall portion 23b including the upper surface of the motor mounting portion 23.

[0036] The tilt drive unit 3 includes a worm mechanism 26 connected to the tilt drive shaft 8 and a gear train 27 including a transmission gear 27b for transmitting the rotation of the output shaft 21a of the tilt drive motor 21 to the worm mechanism 26. That is, the tilt drive unit 3 is configured such that a drive transmission mechanism 28 for transmitting the rotation of the output shaft 21a of the tilt drive motor 21, which is a drive source, to the tilt drive shaft 8 is composed of two gear mechanisms 26 and 27, namely, the worm mechanism 26 and the gear train 27.

[0037] Among them, the worm mechanism 26 includes a worm wheel 26a attached to the tilt drive shaft 8 and a worm shaft 26c having a worm 26b connected to the worm wheel 26a.

[0038] Since the worm wheel 26a is attached to the tilt drive shaft 8 as described above, it is accommodated in the tilt shaft accommodating hole 22a described above.

[0039] Also, in the illustrated example, the worm shaft 26c is provided so as to extend from a position above the worm wheel 26a to the position of the motor mounting portion 23 with its axis L3 oriented in the vertical direction of the frame main body portion 22 with respect to the vertical direction.

[0040] Therefore, a hole (hereinafter, also referred to as "worm shaft accommodation hole 22b") for accommodating the worm shaft 26c provided in this way is formed in the frame main body portion 22. The worm shaft accommodation hole 22b is formed so as to communicate with the inclined shaft accommodation hole 22a in which the worm wheel 26a is accommodated. Further, the worm shaft accommodation hole 22b is formed so as to communicate with the internal space 23a of the motor mounting portion 23 described above in the frame main body portion 22. Also, the worm shaft accommodation hole 22b is formed as a hole that opens on the upper surface of the frame main body portion 22 so that the worm shaft 26c can be inserted from the outside of the frame main body portion 22. Then, a disk-shaped lid member 29 is provided at a portion of the worm shaft accommodation hole 22b that opens on the upper surface of the frame main body portion 22 so as to be fitted into the inner peripheral surface of the hole.

[0041] Also, the worm shaft 26c has the worm 26b described above at an intermediate position in the direction of the axis L3. The worm shaft 26c is supported with respect to the frame main body portion 22 via bearings B4 and B5 provided on both sides in the vertical direction with respect to the worm 26b in such an arrangement that the worm 26b meshes with the worm wheel 26a in the vertical direction within the worm shaft accommodation hole 22b.

[0042] Furthermore, the worm shaft 26c is connected to the output shaft 21a of the tilt drive motor 21 via a gear train 27. More specifically, a drive gear 27a is fixed to a portion of the output shaft 21a of the tilt drive motor 21 attached to the drive support base 5b (motor attachment portion 23) as described above, which is located in the internal space 23a. On the other hand, a driven gear 27c is fixed to the lower end of the worm shaft 26c provided in the frame main body portion 22 as described above. The driven gear 27c and the drive gear 27a are connected via one or more transmission gears 27b in the internal space 23a.

[0043] Since the driven gear 27c is attached to the worm shaft 26c as described above, it is housed in the worm shaft housing hole 22b described above. The rotation of the output shaft 21a of the tilt drive motor 21 is transmitted to the worm mechanism 26 by the gear train 27 composed of the drive gear 27a, the transmission gear 27b, and the driven gear 27c.

[0044] In this way, in the tilt drive unit 3, the rotation of the output shaft 21a of the tilt drive motor 21, which is the drive source, is transmitted to the tilt drive shaft 8 by the drive transmission mechanism 28 composed of the gear train 27 and the worm mechanism 26, and the tilt drive shaft 8 is rotationally driven. Thereby, the tilt drive unit 3 swing-drives the tilt frame 6 supported by the tilt drive shaft 8.

[0045] Also, in the internal space of the drive support base 5b in the tilt drive unit 3, there are storage portions 31 and 32 corresponding to the respective gear mechanisms 26 and 27 for storing lubricating oil for lubricating the corresponding gear mechanisms 26 and 27. Among them, the storage portion 31 corresponding to the worm mechanism 26 is provided in a space (hereinafter, also referred to as the "main body portion side space") 31a composed of the tilt shaft housing hole 22a and the worm shaft housing hole 22b.

[0046] More specifically, as shown in FIG. 4, in the housing hole 22a for the tilt axis, on the side where the tilt drive shaft 8 protrudes, an oil seal 35 is provided in such a manner as to be interposed between the inner peripheral surface of the housing hole 22a for the tilt axis and the outer peripheral surface of the tilt drive shaft 8. Further, in the housing hole 22a for the tilt axis, on the side where the back cover 24 is provided, an oil seal 25 is provided in such a manner as to be interposed between the inner peripheral surface of the through hole 24a in the back cover 24 and the outer peripheral surface of the tilt drive shaft 8. Therefore, the housing hole 22a for the tilt axis is in a state where the portions communicating with the outside of the frame body portion 22 on both sides in the direction of the axis L1 of the tilt drive shaft 8 are sealed.

[0047] Also, as shown in FIG. 3, in the housing hole 22b for the worm shaft in the main body portion side space 31a, an O-ring 36 is provided above the worm shaft 26c in the direction of the axis L3 in such a manner as to be interposed between the outer peripheral surface of the lid member 29 and the inner peripheral surface of the housing hole 22b for the worm shaft. Therefore, the housing hole 22b for the worm shaft is in a state where the portion communicating with the outside of the frame body portion 22 above in the direction of the axis L3 of the worm shaft 26c is sealed.

[0048] Thereby, the main body portion side space 31a constituted by the housing hole 22a for the tilt axis and the housing hole 22b for the worm shaft is in a state where the portions communicating with the outside are sealed. Furthermore, in the main body portion side space 31a, at a position below the lower bearing B5 among the upper and lower bearings B4 and B5 that support the worm 26b in the housing hole 22b for the worm shaft, a first seal member 37, which is an oil seal, is provided in such a manner as to be interposed between the inner peripheral surface of the housing hole 22b for the worm shaft and the outer peripheral surface of the worm shaft 26c. Thereby, the main body portion side space 31a is in a state where the portion above the first seal member 37 is partitioned from the space below the first seal member 37 in the housing hole 22b for the worm shaft.

[0049] And, in the upper part of the main body side space 31a, lubricating oil for lubricating the worm mechanism 26 is stored. Therefore, the upper part thereof serves as a storage part (first storage part) 31 corresponding to the worm mechanism 26.

[0050] In addition, a storage part 32 corresponding to the gear train 27 that connects the output shaft 21a of the tilt drive motor 21 and the worm shaft 26c is provided in a space formed by the internal space 23a in the motor mounting part 23 and a part of the worm shaft accommodation hole 22b that communicates with the internal space 23a.

[0051] More specifically, in the worm shaft accommodation hole 22b, a second seal member 38, which is an oil seal, is provided in such a manner as to be interposed between the inner peripheral surface of the worm shaft accommodation hole 22b and the outer peripheral surface of the worm shaft 26c, below the position where the first seal member 37 described above is provided. Therefore, the worm shaft accommodation hole 22b is also partitioned by the second seal member 38 such that the space (lower space) 22s below the second seal member 38 is separated from the space above it.

[0052] Note that the driven gear 27c described above is attached to the worm shaft 26c at an end portion located below the position where the second seal member 38 is provided. Also, an oil seal 39 is provided in the motor mounting part 23 in such a manner as to be interposed between the inner peripheral surface of the through hole 23c through which the output shaft 21a of the tilt drive motor 21 passes and the outer peripheral surface of the output shaft 21a. Therefore, the internal space 23a in the motor mounting part 23 is in a state where the part communicating with the outside is sealed.

[0053] And, as described above, the internal space 23a in the motor mounting portion 23 and the lower space 22s in the worm shaft housing hole 22b communicate with each other to form one space. The gear train 27 described above is accommodated in that space, and the space for accommodating the gear train 27 is sealed by the oil seal 39 around the output shaft 21a and the second seal member 38 described above. On top of that, lubricating oil for lubricating the gear train 27 is stored in the space for accommodating the gear train 27. Therefore, that space serves as a storage portion (second storage portion) 32 corresponding to the gear train 27.

[0054] Also, as shown in FIGS. 2 and 5, the rotation drive unit 4 is provided to rotationally drive a support shaft 17 rotatably supported by the tilt table 14 and a rotation table 7 attached to the support shaft 17. Therefore, the rotation drive unit 4 includes a rotation drive motor 41 as a drive source for rotationally driving the support shaft 17. And the rotation drive motor 41 of the present embodiment corresponds to the drive motor in the present invention.

[0055] Note that, in the present embodiment, the rotation drive motor 41 is provided in such a manner as to be supported by the other support base (hereinafter, also referred to as "driven support base") 5c of the pair of support bases 5b and 5c in the base frame 5. However, in the tilt circular table device 2, since the support shaft 17 rotationally driven by the rotation drive motor 41 is supported by the tilt frame 6 (tilt table 14) that is swing-driven as described above, the rotation drive motor 41 is provided in such a manner as to be attached to a rotation shaft (hereinafter, also referred to as "driven shaft") 9 rotatably supported with respect to the driven support base 5c. That is, the rotation drive motor 41 is supported by the driven support base 5c via the driven shaft 9. Therefore, the driven support base 5c and the driven shaft 9 also form part of the rotation drive unit 4.

[0056] Further, the support shaft 17 driven by the rotary drive motor 41 is rotatably supported on the tilt table 14 in the tilt frame 6, and is connected to the rotary drive motor 41 by a drive transmission mechanism 43 provided in the tilt frame 6 as described later. Therefore, the support shaft 17 and the tilt frame 6 also form part of the rotary drive unit 4. And regarding the rotary drive unit 4, a rotary table 7 attached to the support shaft 17 and having its angular position determined around the axis L2 of the support shaft 17 corresponds to the rotary target member 7 in the rotation detection device 4.

[0057] Regarding the rotary drive unit 4 in detail, as shown in FIGS. 5 and 6, the driven shaft 9 has a configuration in which a shaft portion 9a formed in a hollow cylindrical shape and a wall portion 9b provided at one end side of the shaft portion 9a are integrally formed. However, the wall portion 9b is formed in a manner that closes the shaft portion 9a at its one end side. The inner diameter of the hollow cylindrical shaft portion 9a is sized to accommodate the rotary drive motor 41. Further, a through hole 9c sized to allow the output shaft 41a of the rotary drive motor 41 to pass through is formed substantially at the center of the wall portion 9b. And the driven shaft 9 is supported with respect to the driven support base 5c via a bearing B2 in such a direction that one end side thereof is located on the tilt drive shaft 8 side with respect to the direction of the axis L1', and at a position where the axis center coincides with the axis center of the tilt drive shaft 8 when viewed in the direction of the axis L1'.

[0058] Then, a part of the rotary drive motor 41 is accommodated in the shaft portion 9a of the driven shaft 9, and the rotary drive motor 41 is attached to the driven shaft 9 with its output shaft 41a directed toward the tilt drive shaft 8 side. In the attached state, the output shaft 41a of the rotary drive motor 41 passes through the through hole 9c in the wall portion 9b of the driven shaft 9 and protrudes from the driven shaft 9 (wall portion 9b) toward the tilt drive shaft 8 side.

[0059] Further, the rotary drive unit 4 includes a worm mechanism 44 connected to the support shaft 17 and a gear train 45 including a transmission gear 45b for transmitting the rotation of the output shaft 41a of the rotary drive motor 41 to the worm mechanism 44. That is, the rotary drive unit 4 is configured such that the drive transmission mechanism 43 for transmitting the rotation of the output shaft 41a of the rotary drive motor 41, which is the drive source, to the support shaft 17 is composed of two gear mechanisms 44 and 45, namely, the worm mechanism 44 and the gear train 45.

[0060] Among them, the worm mechanism 44 is composed of a worm wheel 44a attached to the support shaft 17 and a rotary drive shaft 44c having a worm 44b connected to the worm wheel 44a.

[0061] As shown in FIG. 4, since the worm wheel 44a is attached to the support shaft 17 as described above, it is accommodated in the accommodation hole 14a for the support shaft described above. Further, as shown in FIGS. 5 and 6, the rotary drive shaft 44c has its axis L4 directed in a direction parallel to the axis L1' of the driven shaft 9, and is disposed in the inclined table 14 of the inclined frame 6 such that the worm 44b meshes with the worm wheel 44a.

[0062] Therefore, the inclined table 14 is provided with a hole (accommodation hole for the rotary shaft) 14b for accommodating the rotary drive shaft 44c provided in such a manner, and the accommodation hole 14b for the rotary shaft communicating with the accommodation hole 14a for the support shaft in which the worm wheel 44a is accommodated is formed. The rotary drive shaft 44c is supported with respect to the inclined table 14 via bearings B6 and B7 provided on both sides in the direction of its axis L4 with respect to the worm 44b within the accommodation hole 14b for the rotary shaft. Then, the rotary drive shaft 44c is connected to the output shaft 41a of the rotary drive motor 41 via the gear train 45.

[0063] More specifically, the rotary shaft receiving hole 14b for receiving the rotary drive shaft 44c is formed to open to the side surface of the inclined table 14 on both sides in the direction of the axis L4 of the rotary drive shaft 44c. However, both side surfaces of the inclined table 14 are the side surfaces to which the pair of arm portions 15 and 16 in the inclined frame 6 are respectively attached. Therefore, one end side of the rotary drive shaft 44c in the direction of its axis L4 is on the side of the tilt drive shaft 8, and the other end side is on the side of the driven shaft 9. And the rotary shaft receiving hole 14b is closed by the arm portion 15 on the tilt drive shaft 8 side on the tilt drive shaft 8 side.

[0064] On the other hand, in the arm portion 16 on the driven shaft 9 side, a space (gear train space 16a) extending from the rotary shaft receiving hole 14b of the inclined table 14 to the through hole 9c of the driven shaft 9 is formed inside. Also, as shown in FIG. 6, a through hole 16b that opens toward the rotary shaft receiving hole 14b of the inclined table 14 is formed in the arm portion 16 on the driven shaft 9 side. Therefore, the rotary shaft receiving hole 14b communicates with the gear train space 16a via the through hole 16b on the driven shaft 9 side.

[0065] Then, the end portion of the other end side of the rotary drive shaft 44c is in a state of being located in the gear train space 16a. Further, a through hole 16c that opens toward the through hole 9c of the driven shaft 9 is also formed in the arm portion 16 on the driven shaft 9 side. Therefore, the tip end portion of the output shaft 41a of the rotary drive motor 41 protruding from the driven shaft 9 as described above is also in a state of being located in the gear train space 16a.

[0066] And a drive gear 45a is fixed to a portion of the output shaft 41a of the rotary drive motor 41 that is located within the gear train space 16a. Also, a driven gear 45c is fixed to a portion of the rotary drive shaft 44c that is located within the gear train space 16a. Further, the driven gear 45c and the drive gear 45a are connected via one or more transmission gears 45b within the gear train space 16a. And the rotation of the output shaft 41a of the rotary drive motor 41 is transmitted to the worm mechanism 44 by the gear train 45 composed of the drive gear 45a, the transmission gears 45b, and the driven gear 45c.

[0067] In this way, the rotary drive unit 4 is configured such that the rotation of the output shaft 41a of the rotary drive motor 41, which is the drive source, is transmitted to the support shaft 17 by the drive transmission mechanism 43 composed of the gear train 45 and the worm mechanism 44, and the support shaft 17 is rotationally driven. Thereby, the rotary drive unit 4 rotationally drives the rotary table 7 supported by the support shaft 17.

[0068] Also, in the internal space of the tilt frame 6 in the rotary drive unit 4, there are provided storage portions 33 and 34 corresponding to the respective gear mechanisms 44 and 45 for storing lubricating oil for lubricating the corresponding gear mechanisms 44 and 45.

[0069] Among them, the storage portion 33 corresponding to the worm mechanism 44 is provided within a space (hereinafter, also referred to as the "tilt table side space") 14c composed of the support shaft accommodation hole 14a and the rotary shaft accommodation hole 14b.

[0070] More specifically, as shown in FIG. 4, in the housing hole 14a for the support shaft, on the side where the support shaft 17 protrudes, an oil seal 51 is provided in such a manner as to be interposed between the inner peripheral surface of the housing hole 14a for the support shaft and the outer peripheral surface of the support shaft 17. Further, in the housing hole 14a for the support shaft, on the side where the back cover 19 is provided, an oil seal 52 is provided in such a manner as to be interposed between the inner peripheral surface of the through hole 19a in the back cover 19 and the outer peripheral surface of the support shaft 17. Therefore, the housing hole 14a for the support shaft is in a state where the portions communicating with the outside of the inclined table 14 on both sides in the direction of the axis L2 of the support shaft 17 are sealed.

[0071] Also, as shown in FIG. 6, the housing hole 14b for the rotating shaft is in a state where the portion opening to the inclined drive shaft 8 side is closed by the arm portion 15 on the inclined drive shaft 8 side as described above. An O-ring 53 is interposed between the periphery of the opening of the housing hole 14b for the rotating shaft on the side surface of the inclined drive shaft 8 side and the arm portion 15 on the inclined drive shaft 8 side. Thereby, the inclined table side space 14c constituted by the housing hole 14a for the support shaft and the housing hole 14b for the rotating shaft is in a state where the portions communicating with the outside are sealed.

[0072] Then, in the housing hole 14b for the rotating shaft in the inclined table side space 14c, a third seal member 54, which is an oil seal 54, is provided in such a manner as to be interposed between the inner peripheral surface of the housing hole 14b for the rotating shaft and the outer peripheral surface of the rotary drive shaft 44c on the driven shaft 9 side with respect to the worm 44b in the rotary drive shaft 44c. However, the third seal member 54 is provided on the driven shaft 9 side with respect to the bearing B7 on the driven shaft 9 side among the two bearings B6 and B7 that support the rotary drive shaft 44c described above. Thereby, the inclined table side space 14c is in a state where the portion on the inclined drive shaft 8 side with respect to the third seal member 54 is partitioned from the space on the driven shaft 9 side with respect to the third seal member 54 in the housing hole 14b for the rotating shaft.

[0073] And, in the portion on the tilt drive shaft 8 side in the tilt table side space 14c, lubricating oil for lubricating the worm mechanism 44 is stored. Therefore, the portion on the tilt drive shaft 8 side serves as a storage portion (third storage portion) 33 corresponding to the worm mechanism 44.

[0074] Also, a storage portion 34 corresponding to the gear train 45 that connects the output shaft 41a of the rotary drive motor 41 and the rotary drive shaft 44c is provided in the gear train space 16a of the arm portion 16 on the driven shaft 9 side.

[0075] More specifically, an oil seal 55 is provided in a manner interposed between the inner peripheral surface of the through hole 9c and the outer peripheral surface of the output shaft 41a in the through hole 9c through which the output shaft 41a of the rotary drive motor 41 penetrates in the driven shaft 9. Therefore, on the driven shaft 9 side, the portion of the gear train space 16a that communicates to the outside is in a sealed state. An O-ring 56 is interposed between the periphery of the opening of the through hole 9c on the end surface of the one end side of the driven shaft 9 and the arm portion 16 on the driven shaft 9 side.

[0076] Also, a fourth seal member 57, which is an oil seal 57, is provided in a manner interposed between the inner peripheral surface of the through hole 16b that opens toward the rotary shaft accommodation hole 14b in the arm portion 16 on the driven shaft 9 side and the outer peripheral surface of the rotary drive shaft 44c. By the fourth seal member 57, the gear train space 16a is partitioned from the space (tilt table side space 14c) in the rotary shaft accommodation hole 14b. Then, lubricating oil for lubricating the gear train 45 is stored in the gear train space 16a. Therefore, the gear train space 16a serves as a storage portion (fourth storage portion) 34 corresponding to the gear train 45.

[0077] In the machine tool 1 configured as described above, in the present invention, the rotation indexing device 2 in the machine tool 1 is a detection device for detecting the height position of the lubricating oil stored in the storage portions 31 to 34 (hereinafter, also simply referred to as "height position"), and is provided with detection devices provided one-to-one for the detection target storage portions set as the detection targets among the storage portions 31 to 34.

[0078] And in this embodiment, in the inclined circular table device 2 as the rotation indexing device 2, all of the four storage portions 31 to 34 described above are set as detection target storage portions, and an example is provided with four detection devices 61 to 64. Further, in this embodiment, it is assumed that the inclined circular table device 2 includes display devices 71 to 74 that display information regarding the height position detected by the detection devices 61 to 64. Regarding the characteristic portions of the machine tool 1 including such a rotation indexing device 2, specifically, it is as follows.

[0079] As described above, the inclined circular table device 2 includes the first to fourth storage portions 31 to 34. And the detection devices 61 to 64 are provided one-to-one for each of the storage portions 31 to 34. Regarding each of these detection devices 61 to 64, first, the detection device corresponding to the first storage portion 31 (hereinafter, also referred to as "first detection device") 61 and the related configuration will be described.

[0080] First, as shown in FIG. 3, in the drive support base 5b of the inclination drive unit 3 described above, the worm shaft accommodation hole 22b in the first storage portion 31 has a portion (hereinafter, also referred to as "large diameter portion") 22c formed in such a manner that the inner diameter of the hole 22b is enlarged above the upper bearing B4 among the upper and lower bearings B4 and B5 that support the worm shaft 26c described above.

[0081] On top of that, in the frame main body 22 of the drive support base 5b of the tilt drive unit 3, communication paths (hereinafter also referred to as "frame-side communication paths") 22e, 22f are formed which communicate with the large-diameter portion 22c in the worm shaft accommodation hole 22b and open to the outer side surface (outer side surface) 22d facing the anti-tilt frame side among both side surfaces in the thickness direction of the frame main body 22. Two of them are formed with their positions shifted in the vertical direction of the frame main body 22.

[0082] Among the two frame-side communication paths 22e, 22f, the upper first frame-side communication path 22e is formed so as to communicate with the large-diameter portion 22c at a position close to the upper end in the large-diameter portion 22c. On the other hand, the lower second frame-side communication path 22f is formed so as to communicate with the large-diameter portion 22c at a position close to the lower end in the large-diameter portion 22c. Also, each of the frame-side communication paths 22e, 22f is formed so as to open at a position on the outer side surface 22d opposite to the side of the worm shaft 26c with respect to the tilt drive shaft 8. Therefore, each of the frame-side communication paths 22e, 22f is formed such that the portion communicating with the large-diameter portion 22c extends to a position beyond the tilt drive shaft 8 in the front-rear direction, and is bent at a position opposite to the side of the worm shaft 26c with respect to the tilt drive shaft 8 and formed to open to the outer side surface 22d.

[0083] On top of that, as shown in FIGS. 3 and 4, the first detection device 61 is provided in a manner attached to the outer side surface 22d of the frame main body 22 of the tilt drive unit 3. The first detection device 61 includes a main body block 61a attached to the frame main body 22 of the tilt drive unit 3 and a detector 61h attached to the main body block 61a.

[0084] Among them, the main body block 61a is a member formed in a substantially rectangular parallelepiped shape with four side faces being rectangular and the upper and lower faces being substantially square. And the main body block 61a is attached to the drive support base 5b of the tilt drive unit 3 on one of its four side faces. Accordingly, that side face becomes the attachment surface 61b. Further, in the main body block 61a, there is a hole 61c for providing a detector 61h to be described later, and a bottomed hole (hereinafter also referred to as a "detection hole") 61c that opens to the upper surface and is closed on the lower surface side is formed.

[0085] Furthermore, in the main body block 61a, two communication passages (hereinafter also referred to as "detector-side communication passages") 61d and 61e that communicate with the detection hole 61c and open to the attachment surface 61b are formed with their positions shifted in the depth direction of the detection hole 61c. Note that, among the two detector-side communication passages 61d and 61e, the upper first detector-side communication passage 61d and the lower second detector-side communication passage 61e are formed so that the interval therebetween coincides with the interval in the vertical direction between the first frame-side communication passage 22e and the second frame-side communication passage 22f described above.

[0086] Then, the detector 61h is provided in a manner attached to the upper surface of the main body block 61a. Regarding the detector 61h, in this embodiment, a so-called guided pulse type level sensor that detects the position of the detection target (the oil level) by microwaves is adopted. Specifically, the detector 61h is composed of a detector main body portion 61i that is a portion attached to the upper surface of the main body block 61a, and a rod-shaped detection rod 61j provided so as to protrude from the detector main body portion 61i.

[0087] The detector 61h calculates the distance to the detection target based on the time it takes for the microwave transmitted from the detector main body 61i toward the detection target to be reflected by the detection target (the oil level) and received by the detector main body 61i. The detection rod 61j is for assisting the transmission and reception of microwaves in the detector main body 61i. The detector 61h is attached to the upper surface of the main body block 61a in the detector main body 61i in such a manner that the detection rod 61j is positioned within the detection hole 61c of the main body block 61a.

[0088] Furthermore, the first detection device 61 is attached to the outer side surface 22d of the frame main body 22 of the drive support base 5b of the tilt drive unit 3 on its mounting surface 61b in such an arrangement that the first detector-side communication passage 61d communicates with the first frame-side communication passage 22e and the second detector-side communication passage 61e communicates with the second frame-side communication passage 22f. As a result, the detection hole 61c in the first detection device 61 is in communication with the first storage portion 31 via the respective detector-side communication passages 61d, 61e and the respective frame-side communication passages 22e, 22f. An O-ring 61p is interposed between the periphery of the opening of the first detector-side communication passage 61d on the mounting surface 61b of the main body block 61a and the outer side surface 22d of the frame main body 22. Also, an O-ring 61q is interposed between the periphery of the opening of the second detector-side communication passage 61e on the mounting surface 61b of the main body block 61a and the outer side surface 22d of the frame main body 22.

[0089] As a result, when the oil level of the lubricating oil stored in the first storage portion 31 to lubricate the worm mechanism 44 as described above exists between the first frame-side communication passage 22e and the second frame-side communication passage 22f in the large-diameter portion 22c in the vertical direction, the lubricating oil flows into the detection hole 61c through the second frame-side communication passage 22f and the second detector-side communication passage 61e, and the height position in the detection hole 61c and the height position in the first storage portion 31 are in a coincident state.

[0090] Regarding the lubricating oil stored in the first storage portion 31, in this embodiment, the upper and lower bearings B4 and B5 that support the worm shaft 26c are also lubricated with the lubricating oil. Therefore, the height position in the first storage portion 31 needs to be at least above the upper bearing B4. Thus, the lower limit of the height position is determined to be a position slightly above the upper bearing B4.

[0091] On top of that, in the first storage portion 31, the large-diameter portion 22c is formed immediately above the upper bearing B4, and the lower second frame-side communication passage 22f of the two frame-side communication passages 22e and 22f is formed to communicate with the large-diameter portion 22c at a position close to the lower side of the large-diameter portion 22c as described above. Thereby, even when the height position in the first storage portion 31 reaches the lower limit, the height position in the detection hole 61c matches the height position in the first storage portion 31. Therefore, it is possible to detect the state where the height position in the first storage portion 31 reaches the lower limit by the first detection device 61.

[0092] Also, regarding the upper limit of the height position, in the inclined circular table device 2, during operation, the temperature of the lubricating oil rises, and the volume of the lubricating oil may expand as the temperature rises. In that case, if the size of the space above the oil level of the first storage portion 31 in the initial state before operating the inclined circular table device 2 is so small that it cannot accommodate the expansion, the pressure of the lubricating oil will rise during the operation as the expansion occurs. Therefore, it is desired that the height position in the initial state is a position where a space large enough to accommodate at least the expansion during operation is formed above the oil level. Thus, the height position in the initial state is determined to be a position where such a space is formed above the oil level.

[0093] On top of that, the upper first frame-side communication passage 22e is formed so as to communicate with the large-diameter portion 22c at a position close to the upper end of the large-diameter portion 22c as described above. That is, the first frame-side communication passage 22e is formed so that the detection hole 61c communicates with the space formed above the oil level in the first storage portion 31. As a result, air can move between the first storage portion 31 and the detection hole 61c. Thereby, even in a state where the height position in the first storage portion 31 is located near the upper end of the first storage portion 31, the height position in the detection hole 61c is made to coincide with the height position in the first storage portion 31. Therefore, it is possible to detect even a state where the height position of the first storage portion 31 is located near the upper end of the first storage portion 31 by the first detection device 61.

[0094] Next, a detection device corresponding to the second storage portion 32 (hereinafter, also referred to as the "second detection device") 62 and the related configuration will be described. Note that the configuration of the second detection device 62 itself is substantially the same as the configuration of the first detection device 61 described above.

[0095] First, as shown in FIGS. 2 and 3, the second storage portion 32 includes the internal space 23a of the motor mounting portion 23 in the drive support base 5b of the tilt drive portion 3 as described above. On top of that, in the motor mounting portion 23, two through holes 22i and 22j are formed in a vertical arrangement with respect to the side wall 22h including the side surface (outer side surface 23d) facing the same side as the outer side surface 22d of the frame main body portion 22 to which the first detection device 61 is attached. Therefore, the internal space 23a of the motor mounting portion 23 communicates with the outside through the through holes 22i and 22j, and the two through holes 22i and 22j correspond to the frame-side communication passages 22e and 22f in the configuration related to the first detection device 61 described above.

[0096] Of the two through holes 22i and 22j, the upper through hole 22i is provided so as to open into the internal space 23a at a position near the upper end in the internal space 23a. On the other hand, the lower through hole 22j is provided so as to open into the internal space 23a below the gear train 27 in the motor mounting portion 23.

[0097] Furthermore, the second detection device 62 is provided in a manner attached to the outer side surface 23d of the motor mounting portion 23. However, in the second detection device 62, the interval between the two detector-side communication passages (the upper first detector-side communication passage 62d and the lower second detector-side communication passage 62e) in the main body block 62a is made to coincide with the interval between the two through holes 22i and 22j in the motor mounting portion 23 described above.

[0098] The second detection device 62 is attached to the outer side surface 23d of the motor mounting portion 23 on its mounting surface 62b in such an arrangement that the first detector-side communication passage 62d communicates with the upper through hole 22i in the motor mounting portion 23 and the second detector-side communication passage 62e communicates with the lower through hole 22j. Thereby, the detection hole 62c in the second detection device 62 is in a state of being communicated with the second reservoir 32 via the detector-side communication passages 62d and 62e and the through holes 22i and 22j.

[0099] Regarding the lubricating oil stored in the second reservoir 32, the height position in the initial state is determined to be a position where a space of a size that allows at least the expansion during operation is formed above the oil level, similar to the height position in the first reservoir 31. The upper through hole 22i is provided at a position near the upper end in the internal space 23a as described above, and the height position in the detection hole 62c is made to coincide with the height position in the internal space 23a, so that the second detection device 62 can detect the height position.

[0100] Also, the height position needs to be above the lower surface of the gear train 27 that is the object of lubrication. Therefore, the lower through-hole 22j is provided below the gear train 27 as described above. That is, the second detection device 62 is provided so as to be able to detect the height position down to a position below the gear train 27. However, the lower limit of the height position of the lubricating oil in the second reservoir 32 is determined to be a position slightly above the lower surfaces of all the gears 27a, 27b, 27c included in the gear train 27 described above. An O-ring 62p is interposed between the periphery of the opening of the first detector-side communication passage 62d on the mounting surface 62b of the main body block 62a and the outer side surface 23d of the motor mounting portion 23. Also, an O-ring 62q is interposed between the periphery of the opening of the second detector-side communication passage 62e on the mounting surface 62b of the main body block 62a and the outer side surface 23d of the motor mounting portion 23.

[0101] Next, as shown in FIG. 6, a detection device (hereinafter also referred to as the "third detection device") 63 corresponding to the third reservoir 33 and related configurations will be described.

[0102] First, in the inclined table 14 described above, the accommodation hole 14b for the rotating shaft in the third reservoir 33 is formed such that the portion where the worm 44b is accommodated has a larger diameter portion (hereinafter also referred to as the "worm large-diameter portion") 14d with a larger inner diameter than the other portions. Then, as shown in FIG. 2, in the inclined table 14, two through-holes 14h, 14i are formed side by side in the plate thickness direction with respect to the front wall 14f including the front side surface 14e of the inclined table 14.

[0103] As shown in FIG. 6, among the two through-holes 14h, 14i, the upper through-hole 14h is formed to open into the worm large-diameter portion 14d at a position close to the upper surface side (upper end) of the inclined table 14 in the plate thickness direction of the worm large-diameter portion 14d. On the other hand, the lower through-hole 14i is formed to open into the worm large-diameter portion 14d at a position close to the lower surface side (lower end) of the inclined table 14 in the plate thickness direction of the worm large-diameter portion 14d.

[0104] On top of that, the third detection device 63 is provided in a manner attached to the front surface 14e of the inclined table 14. In the third detection device 63, the main body block 63a is formed such that its upper surface and lower surface also form a rectangular shape with respect to the main body blocks 61a and 62a of the first and second detection devices 61 and 62. However, the upper surface and the lower surface forming the rectangular shape are surfaces formed such that the dimension in the long side direction is sufficiently larger than the dimension in the short side direction. Therefore, two of the four side surfaces are also surfaces formed such that the dimension in the long side direction is sufficiently larger than the dimension in the short side direction (hereinafter also referred to as "horizontally long side surfaces"). The third detection device 63 is attached to the inclined table 14 on one of its horizontally long side surfaces, and the horizontally long side surface serves as the attachment surface 63b.

[0105] Also, as shown in FIG. 2, in the main body block 63a, the detection hole 63c that opens on the upper surface is formed at a position close to one end side in the long side direction. Further, in the main body block 63a, two detector-side communication paths 63d and 63e that communicate with the detection hole 63c are formed to open to the attachment surface 63b at a position close to the other end side in the long side direction. In addition, the interval between the openings of the two detector-side communication paths (the upper first detector-side communication path and the lower second detector-side communication path) 63d and 63e in the main body block 63a on the attachment surface 63b coincides with the interval between the two through holes 14h and 14i in the inclined table 14 described above.

[0106] On top of that, the third detection device 63 is arranged such that the first detector-side communication passage 63d communicates with the upper through-hole 14h in the inclined table 14 and the second detector-side communication passage 61e communicates with the lower through-hole 14i, and is attached to the front surface 14e of the inclined table 14 on its mounting surface 63b. Therefore, the two through-holes 14h and 14i in the inclined table 14 correspond to the frame-side communication passages 22e and 22f in the configuration related to the first detection device 61 described above. As shown in FIG. 6, an O-ring 63p is interposed between the periphery of the opening of the first detector-side communication passage 63d on the mounting surface 63b of the main body block 63a and the front surface 14e of the inclined frame 14. Also, an O-ring is interposed between the periphery of the opening of the second detector-side communication passage 63e on the mounting surface 63b of the main body block 63a and the front surface 14e of the inclined frame 14.

[0107] Regarding the lubricating oil stored in the third storage portion 33, in the state of the inclined circular table device 2 in which the upper surface of the rotary table 7 is parallel to the horizontal direction (hereinafter, also simply referred to as the "horizontal state"), the height position needs to be above the meshing position in the worm mechanism 44 (worm 44b, worm wheel 44a) that is the object of lubrication. Therefore, the lower through-hole 14i is provided at a position close to the lower end of the large-diameter portion 14d for the worm described above. However, the lower limit of the height position of the lubricating oil in the third storage portion 33 is determined to be a position slightly above the meshing position.

[0108] Also, regarding the upper limit of the height position, the third storage portion 33 includes the support shaft housing hole 14a as described above, and the support shaft housing hole 14a has a portion above the large-diameter portion 14d for the worm in the horizontal state. Therefore, the third storage portion 33 can allow the expansion of the lubricating oil during the operation of the inclined circular table device 2 by the support shaft housing hole 14a even when the large-diameter portion 14d for the worm is filled with the lubricating oil.

[0109] However, if the large-diameter portion 14d for the worm is filled with lubricating oil, in the configuration where the through-holes (frame-side communication passages) 14h and 14i are formed at the positions as described above, air cannot move between the storage portion (large-diameter portion 14d for the worm) 33 and the detection hole 63c. Therefore, for the third storage portion 33, the upper limit of the height position is determined to be slightly below the upper through-hole (frame-side communication passage) 14h in the horizontal state. And by determining the upper limit of the height position with respect to the upper through-hole 14h in this way, it becomes possible to detect the height position of the third storage portion 33 with the third detection device 63.

[0110] Next, a detection device corresponding to the fourth storage portion 34 (hereinafter, also referred to as the "fourth detection device") 64 and the related configuration will be described. Note that the configuration of the fourth detection device 64 itself is substantially the same as the configuration of the first detection device 61 described above.

[0111] First, the fourth storage portion 34 includes the gear train space 16a in the arm portion 16 on the driven shaft 9 side as described above. Then, as shown in FIG. 2, on the arm portion 16 on the driven shaft 9 side of the rotary drive unit 4, two through-holes 16h and 16i are formed in a vertical arrangement with respect to the front wall 16e including the surface facing the same side as the front surface 14e of the inclined table 14 described above (the front surface 16d in the arm portion 16 on the driven shaft 9 side). Therefore, the gear train space 16a in the arm portion 16 on the driven shaft 9 side communicates with the outside through the through-holes 16h and 16i, and the two through-holes 16h and 16i correspond to the frame-side communication passages 22e and 22f in the configuration related to the first detection device 61 described above.

[0112] Of the two through holes 16h and 16i, the lower through hole 16i is formed to penetrate the front wall 16e at a position below the transmission gear 45b in the gear train space 16a in the horizontal state. Then, as shown in FIGS. 2 and 6, the upper through hole 16h is formed to penetrate the front wall 16e at a position where the distance between the upper through hole 16h and the lower through hole 16i coincides with the distance between the two detector side communication passages 64d and 64e in the main body block 64a of the fourth detection device 64.

[0113] The fourth detection device 64 is arranged such that the first detector side communication passage 64d communicates with the upper through hole 16h in the arm portion 16 on the driven shaft 9 side and the second detector side communication passage 64e communicates with the lower through hole 16i, and is attached to the front side surface 16d of the arm portion 16 on the driven shaft 9 side at its mounting surface 64b. Thereby, the detection hole 64c in the fourth detection device 64 is in a state of communicating with the fourth storage portion 34 via the detector side communication passages 64d and 64e and the through holes 16h and 16i. An O-ring 64p is interposed between the periphery of the opening of the first detector side communication passage 64d on the mounting surface 64b of the main body block 64a and the front side surface 16d of the arm portion 16 on the driven shaft 9 side. Also, an O-ring is interposed between the periphery of the opening of the second detector side communication passage 64e on the mounting surface 64b of the main body block 64a and the front side surface 16d of the arm portion 16 on the driven shaft 9 side.

[0114] Regarding the lubricating oil stored in the fourth storage portion 34, the driving gear 45a, which is the uppermost one in the gear train 45 to be lubricated in the horizontal state, is indirectly lubricated by the transmission gear 45b meshing with the driving gear 45a being lubricated. Therefore, the height position needs to be at least a position where the transmission gear 45b is lubricated with the lubricating oil. Thus, the lower limit of the height position is determined to be a position slightly above the meshing position between the transmission gear 45b and the driven gear 45c in the horizontal state.

[0115] Also, regarding the upper limit of the height position, the fourth storage portion 34 includes the gear train space 16a as described above, and the gear train space 16a is a space where there is a large space above the gear train 45 (drive gear 45a). Therefore, even if the gear train space 16a is filled with lubricating oil so that the gear train 45 is immersed, the fourth storage portion 34 is capable of allowing for the expansion of the lubricating oil during the operation of the inclined circular table device 2.

[0116] However, similar to the other detection devices 61 to 63, it is necessary that air can move between the gear train space 16a and the detection hole 64c. Therefore, also for the fourth storage portion 34, similar to the third storage portion 33, the upper limit of the height position is determined at a position slightly lower than the upper through hole (frame side communication passage) 16h in the horizontal state. And by determining the upper limit of the height position with respect to the upper through hole 16h in this way, it becomes possible to detect the height position of the fourth storage portion 34 with the fourth detection device 64.

[0117] Furthermore, as shown in FIG. 2, in this embodiment, the inclined circular table device 2 includes display devices 71 to 74 that are connected to the detection devices 61 to 64 and display information regarding the height positions detected by the detection devices 61 to 64. And in this embodiment, it is assumed that the display devices 71 to 74 are provided one-to-one for each detection device. Therefore, four display devices 71 to 74 are provided in the inclined circular table device 2 of this embodiment. However, in this embodiment, each of the display devices 71 to 74 is attached to the upper part of the detector main body portions 61i to 64i in the detectors 61h to 64h of the corresponding detection devices 61 to 64 and is provided integrally with the detectors 61h to 64h. Also, it is assumed that the configuration of each of the display devices 71 to 74 itself is the same in each of the detection devices 61 to 64.

[0118] Also, the information regarding the height position displayed by the display devices 71 to 74 shall be the detection results (the distances from the detector main body parts 61i to 64i to the oil surface) by the detectors 61h to 64h in the respective detection devices 61 to 64. And the display devices 71 to 74 shall be configured to display the detection results in numbers. Therefore, each of the display devices 71 to 74 includes display parts 71a to 74a that display numbers corresponding to the detection results in the corresponding detection devices 61 to 64.

[0119] In addition, each of the display devices 71 to 74 is provided integrally with the detectors 61h to 64h as described above and is provided inside the exterior cover 1f of the machine tool 1. Therefore, each of the display devices 71 to 74 is provided in a direction such that an operator can visually observe the display parts 71a to 74a from the outside of the exterior cover 1f in the above-described initial state and horizontal state.

[0120] According to the machine tool 1 including the tilt circular table device 2 described above, for the first to fourth storage parts 31 to 34 which are the detection target storage parts, the height positions of the lubricating oil stored in the respective storage parts 31 to 34 are detected by the detection devices 61 to 64 provided in a one-to-one correspondence with the respective storage parts 31 to 34. And the detection results by the respective detection devices 61 to 64 are displayed on the display parts 71a to 74a of the display devices 71 to 74 provided integrally with the detectors 61h to 64h in the respective detection devices 61 to 64. Therefore, by visually observing the display parts 71a to 74a (display content), the operator can confirm the detection results.

[0121] Note that, as described above, the detection result is the distance from the detectors 61h to 64h (detector main bodies 61i to 64i) to the oil level. However, since the relationship between the height position (oil quantity) of the oil level in each storage section 31 to 34 and that distance is unique, by checking that distance, the operator can grasp the height position. Further, for each of the storage sections 31 to 34, although the upper limit and the lower limit of the height position are defined as described above, the state of the height position with respect to the upper limit and the lower limit can also be grasped. For example, for each of the storage sections 31 to 34, by converting the upper limit and the lower limit of the height position into the distance and enabling the operator to check the value, the comparison between the upper limit and the lower limit and the detection result can be performed more easily.

[0122] And, as described above, by providing the display devices 71 to 74 such that the display units 71a to 74a can be visually recognized from the outside of the exterior cover 1f of the machine tool 1, for example, before the start of operation of the machine tool 1 in which the tilt circular table device 2 is in the initial state (the horizontal state), the state of the height position in each of the storage sections 31 to 34 can be easily confirmed from the outside of the exterior cover 1f. Therefore, according to such a machine tool 1, compared with a machine tool 1 including a conventional rotary indexing device in which the oil quantity is managed using an oil gauge, it becomes easier for the operator to grasp the state of the height position of each of the storage sections 31 to 34.

[0123] Note that the present invention is not limited to the embodiments (the examples) described above, and can also be implemented in other embodiments (modification examples) as follows.

[0124] (1) Regarding the rotary indexing device included in the machine tool on which the present invention is premised, in the above example, the tilt circular table device 2 including two types of rotary indexing devices 3 and 4, namely, the tilt drive unit 3 and the rotary drive unit 4, is adopted. However, the rotary indexing device in the present invention is not limited to such a tilt circular table device, and may be a tilt table device composed only of a rotary indexing device corresponding to the tilt drive unit 3 in the above example, or a circular table device composed only of a rotary indexing device corresponding to the rotary drive unit in the above example.

[0125] Further, the circular table device may be a so-called vertically arranged circular table device configured to determine the angular position of the rotation target member around a horizontal axis, or a so-called horizontally arranged circular table device configured to determine the angular position of the rotation target member around a vertical axis.

[0126] Regarding each rotation detection device, in the above embodiment, the rotation shaft (tilt drive shaft 8, support shaft 17) to which the rotation target member is attached and the drive motor are connected via two gear mechanisms, namely, a worm mechanism and a gear train. As a result, there are two storage portions in each rotation detection device. However, in the present invention, the rotation detection device may be configured such that the rotation shaft and the drive motor are connected by one gear mechanism such as a worm mechanism. In that case, there is one storage portion in the rotation detection device.

[0127] (2) Regarding the detection target storage portion, in the above embodiment, in the configuration where the four storage portions 31 to 34 are included in the rotation detection device, all of the four storage portions 31 to 34 are set as the detection target storage portions. That is, all of the storage portions 31 to 34 included in the rotation detection device are set as the detection target storage portions. However, in the present invention, even when the rotation detection device includes a plurality of storage portions, not all of them are necessarily set as the detection target storage portions, and only some of the storage portions may be set as the detection target storage portions.

[0128] (3) Regarding the detection device, in the above embodiment, the detection device employs a guide pulse type level sensor as the detectors 61h to 64h. However, in the present invention, the detection device may employ, for example, an ultrasonic type level sensor or a laser type level sensor as the detector.

[0129] In addition, in the present invention, the detection device is not limited to one that employs a detector capable of linearly detecting the position of such a detection target (the oil level). Instead, it may employ a detector (for example, an optical level sensor or a float type level sensor) capable of detecting that the detection target (the oil level) has reached (exceeded) a predetermined detection position.

[0130] Note that with such a detector, it is not possible to detect the height position itself as in the detector of the above-described embodiments. However, for example, by setting the lower limit of the above-described height position as the detection position, it is possible to grasp that the height position has fallen below the lower limit, which is a problem in lubricating the gear mechanism. Therefore, in terms of the oil quantity management aimed at by the present invention, the detector can also be accommodated by a detection device of this type. And although the detection device in the present invention is one that "detects the height position", the "detection of the height position" also includes detecting the state of the height position.

[0131] (4) Regarding the display device, the above-described embodiments are examples in which display devices 71 to 74 for displaying information regarding the height position detected by the detection devices 61 to 64 are provided. Moreover, the display devices 71 to 74 are provided integrally with the detectors 61h to 64h of the corresponding detection devices 61 to 64. However, even when the machine tool is equipped with a display device in such a manner, in the present invention, the display device is not limited to being provided integrally with the detector. For example, the display device may be provided in a manner attached to the outer surface of the peripheral wall 1h of the exterior cover 1f on the outside of the exterior cover 1f of the machine tool 1. Further, the display device is not limited to one that displays the detection result by the detection device in numbers as in the above-described embodiments, and may be one that displays a message corresponding to the detection result in characters, or may be one that lights a warning lamp according to the detection result.

[0132] However, in the present invention, it is not essential to provide such a display device, and the machine tool according to the present invention may not be provided with a display device. For example, instead of the above-described display device, an alarm that emits a warning sound according to the detection result of the detection device may be provided. Further, the information regarding the height position detected by the detection device may be output to the control device of the machine tool and used by the control device of the machine tool. Note that the usage method by the control device is, for example, a method of preventing the operation of the machine tool when information corresponding to the height position falling below the lower limit is input to the control device.

[0133] (5) Regarding the machine tool, the above embodiment is an example in which the present invention is applied to a machine tool 1 (so-called horizontal machining center) whose spindle 1a has a horizontal rotation axis direction. However, the machine tool to which the present invention is applied is not limited to a horizontal machining center, and may be, for example, a machine tool (so-called vertical machining center) whose spindle has a vertical rotation axis direction.

[0134] Further, the present invention is not limited to any of the embodiments described above, and can be appropriately changed without departing from the gist thereof.

Explanation of Signs

[0135] 1 Machine tool 1a Spindle 1b Bed 1c Column 1d Spindle head 1e Table 1f Exterior cover (cover) 1h Peripheral wall 2 Inclined circular table device (rotation indexing device) 3 Inclined drive unit (rotation indexing device) 4 Rotation drive unit (rotation indexing device) 5 Base frame 5a Mounting frame 5b Support base (drive support base) 5c Support base (driven support base) 6 Inclined frame (rotating member) 7 Rotating table (rotating member) 8 Rotating shaft (tilting drive shaft) 9 Rotating shaft (driven shaft) 9a Shaft portion 9b Wall portion 9c Through hole 14 Inclined table 14a Accommodating hole for support shaft 14b Accommodating hole for rotating shaft 14c Space on the inclined table side 14d Large diameter portion for worm 14e Front surface 14f Front wall 14h Through hole 14i Through hole 15 Arm portion (arm portion on the tilting drive shaft side) 16 Arm portion (arm portion on the driven shaft side) 16a Space for gear train 16b Through hole 16c Through hole 16d Front surface 16e Front wall 16h Through hole 16i Through hole 17 Support shaft 19 Rear cover 19a Through hole 21 Tilting drive motor 21a Output shaft 22 Frame main body portion 22a Accommodating hole for tilting shaft 22b Accommodating hole for worm shaft 22c Large diameter portion 22d Outer side surface 22e Frame side communication path (first frame side communication path) 22f Frame side communication path (second frame side communication path) 22h Side wall 22i Through hole 22j Through hole 22r Front surface 22s Lower space 23 Motor mounting portion 23a Internal space 23b wall part 23c through-hole 23d outer side surface 24 back cover 24a through-hole 25 oil seal 26 worm mechanism (gear mechanism) 26a worm wheel 26b worm 26c worm shaft 27 gear train 27a drive gear 27b transmission gear 27c driven gear 28 drive transmission mechanism 29 cover member 31 storage part (first storage part) 31a space on the main body part side 32 storage part (second storage part) 33 storage part (third storage part) 34 storage part (fourth storage part) 35 oil seal 36 O-ring 37 first seal member 38 second seal member 39 oil seal 41 rotation drive motor (drive motor) 41a output shaft 43 drive transmission mechanism 44 worm mechanism (gear mechanism) 44a worm wheel 44b worm 44c rotation drive shaft 45 gear train 45a drive gear 45b transmission gear 45c driven gear 51 oil seal 52 oil seal 53 O-ring 54 third seal member (oil seal) 55 oil seal 56 O-ring 57 fourth seal member (oil seal) 61 Detection device (first detection device) 61a Body block 61b Mounting surface 61c Detection hole 61d Detector-side communication path (first detector-side communication path) 61e Detector-side communication path (second detector-side communication path) 61h Detector 61i Detector body part 61j Detection rod 61p O-ring 61q O-ring 62 Detection device (second detection device) 62a Body block 62b Mounting surface 62c Detection hole 62d Detector-side communication path (first detector-side communication path) 62e Detector-side communication path (second detector-side communication path) 62h Detector 62i Detector body part 62j Detection rod 62p O-ring 62q O-ring 63 Detection device (third detection device) 63a Body block 63b Mounting surface 63c Detection hole 63d Detector-side communication path (first detector-side communication path) 63e Detector-side communication path (second detector-side communication path) 63h Detector 63i Detector body part 63j Detection rod 63p O-ring 64 Detection device (fourth detection device) 64a Body block 64b Mounting surface 64c Detection hole 64d Detector-side communication path (first detector-side communication path) 64e Detector-side communication path (second detector-side communication path) 64h Detector 64i Detector body part 64j Detection Rod 64p O-ring 71 Display Device 71a Display Section 72 Display Device 72a Display Section 73 Display Device 73a Display Section 74 Display Device 74a Display Section

[0136] Axis L1 Axis L1’ Axis L2 Axis L3 Axis L4 Bearing B1 Bearing B2 Bearing B3 Bearing B4 Bearing B5 Bearing B6 Bearing B7

Claims

【Claim 1】 A machine tool including a rotation detection device for determining the angular position of a rotatable member attached to an end of a rotating shaft, the rotation detection device including a frame that houses the rotating shaft in a rotatably supported state, a drive motor that rotationally drives the rotating shaft, and a drive transmission mechanism that is housed in a space inside the frame and transmits the rotation of the output shaft of the drive motor to the rotating shaft, the drive transmission mechanism including a gear mechanism composed of a plurality of gears that mesh with each other, the space corresponding to the gear mechanism and including one or more storage portions in which lubricating oil for lubricating the gear mechanism is stored, the storage portions being partitioned from other portions of the space by a seal member, in a machine tool including a rotation detection device, including a detection device for detecting the height position of the oil level of the lubricating oil stored in the storage portion, the detection device being provided one-to-one for each detection target storage portion set as a detection target among one or more of the storage portions, A machine tool including a rotation detection device, characterized by the above.

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