Boring Equipment

Abstract

To provide a boring device that is able to reduce man-hours for work, by detecting a state of a boring tool being caught by a support member, before this state actually happens.SOLUTION: A boring device 1 includes: a boring tool T having a shaft-like blade portion 21 with a blade 21a on an outer peripheral surface thereof and having a support shaft portion 22 positioned at least on an axial tip side from the blade portion 21; a support member 51 having a through-hole into which the support shaft portion 22 of the boring tool T can be inserted, and supporting the outer peripheral surface of the inserted support shaft portion 22; and a control device 7 that acquires an axial load R of the boring tool T generated in a feed device 5 when the support shaft portion 22 of a boring tool T is inserted into the support member 51, and that stops a feed operation of the feed device 5 when the acquired load R exceeds a set value Rth.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a boring machine. [Background technology]

[0002] For example, a cylinder block is formed with through holes for supporting a camshaft and through holes for supporting a crankshaft journal. As described in Patent Documents 1 and 2, it is known to use a boring tool to machine these through holes. This type of boring tool has a long shape that is prone to bending, so it is necessary to suppress the bending. Therefore, Patent Document 1 describes that a support member is used to rotatably support the tip and base ends of the boring tool in order to suppress the bending. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-205825 A [Patent Document 2] JP 2014-104523 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to support the boring tool with high precision, the radial gap between the inner peripheral surface of the support member and the outer peripheral surface of the boring tool is set to an extremely small dimension, so that when the boring tool is inserted into the support member, there is a risk that the boring tool will get caught on the support member due to adhesion of foreign matter such as cutting chips or other disturbance factors, making it impossible to move the boring tool in the axial direction.

[0005] When this happens, the worker hits the boring tool with a hammer or the like while pulling it out of the support member. If the boring tool or the support member is scratched, the worker repairs the damaged area and checks the accuracy of the machine. Therefore, if a stuck state occurs, a lot of repair work is required.

[0006] The present invention has been made in consideration of such problems, and aims to provide a boring device that can reduce work hours by detecting before the boring tool gets caught on the support member. [Means for solving the problem]

[0007] One aspect of the present invention is A boring tool having a shaft-shaped blade portion having a blade on an outer circumferential surface and a support shaft portion located at least on the axial tip side of the blade portion; A spindle device that holds and rotates the boring tool; a workpiece support table for supporting a workpiece to be machined by the boring tool; a feed device that moves the boring tool relative to the workpiece support in an axial direction of the boring tool; a support member that is provided on at least the opposite side of the spindle device from the workpiece support table, has a through hole into which the support shaft portion of the boring tool can be inserted, and supports an outer peripheral surface of the inserted support shaft portion; a control device that acquires a load in an axial direction of the boring tool generated in the feed device when the support shaft portion is inserted into the support member by a feed operation of the feed device, and stops the feed operation of the feed device when the acquired load exceeds a set value; Equipped with picture, the set value is a value smaller than a load generated in the feed device when the feed device is driven in a state in which the support shaft portion is axially hooked on the support member, the control device, when performing a machining cycle for a plurality of the workpieces in succession, executes an operation of inserting the boring tool into the support member before machining each of the workpieces; The set value is set to a load generated when the boring tool is inserted into the support member in a machining cycle of the workpiece that is one or more pieces before the workpiece when the support shaft portion is caught in the axial direction of the support member. Located in the boring device. Effect of the Invention

[0008] It was found that, during the operation of inserting the boring tool into the support member, the axial load of the boring tool caused by the feeding device starts to increase before the support shaft of the boring tool gets caught on the support member. Therefore, according to the above boring device, the control device acquires the axial load of the boring tool generated on the feeding device when the support shaft is being inserted into the support member by the feeding operation of the feeding device. Then, the control device stops the feeding operation of the feeding device when the acquired load exceeds a set value.

[0009] The state in which the axial load acting on the feed device reaches the set value can be set to a state before the support shaft of the boring tool gets caught on the support member, and therefore the feed operation of the feed device can be stopped before the support shaft of the boring tool gets caught on the support member.

[0010] Then, the worker can pull out the boring tool from the support member by performing a return operation after stopping the feeding operation of the feed device. The worker then performs maintenance work on the boring tool and the support member. This maintenance work is much easier than the work required to correct a state in which the support shaft of the boring tool is caught on the support member. Therefore, the number of work steps can be significantly reduced. [Brief description of the drawings]

[0011] [Figure 1] FIG. 13 is a diagram showing the boring device, illustrating a processing preparation state before the boring tool is inserted into the support member in the processing cycle. [Diagram 2] FIG. 2 is a functional block diagram of a portion of the configuration of the boring device. [Diagram 3] FIG. 2 is a diagram showing the boring device, illustrating a state in which machining is performed by a boring tool in a machining cycle. [Figure 4]This is a graph showing the axial load of the boring tool generated in the feed device for each machining cycle of the workpiece, the setting value for stopping the pre-machining feed operation by the feed device, and the load when the boring tool is caught on the support member. [Diagram 5] 4 is a flowchart showing processing of a machining cycle by a control device. [Figure 6] FIG. 11 is a functional block diagram of a partial configuration of a boring device in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (1. Configuration of boring device 1) The configuration of the boring device 1 will be described with reference to Fig. 1. The boring device 1 processes the inner surface of the through hole Wa of the workpiece W by moving the boring tool T relatively to the workpiece W in the axial direction of the boring tool T while rotating the boring tool T. In this embodiment, since the boring tool T is long, the boring device 1 is a horizontal boring device in which the central axis of the boring tool T is aligned horizontally. However, depending on the length of the boring tool T, a vertical boring device can also be used.

[0013] In this embodiment, an engine block is taken as an example of the workpiece W, and the through holes Wa serving as the machined portions of the workpiece W are through holes for supporting a camshaft of the engine block, through holes for supporting a journal of a crankshaft, etc. Here, a plurality of such through holes are formed coaxially in the engine block, and the boring device 1 can simultaneously machine the inner circumferential surfaces of the plurality of through holes Wa in the workpiece W. Note that the workpiece W machined by the boring device 1 is not limited to an engine block, and can be various other objects.

[0014] As shown in FIG. 1, the boring device 1 includes a boring tool T, a base 2, a spindle device 3, a workpiece support table 4, a feed device 5, and a support member 6.

[0015] The boring tool T has an elongated shape in the axial direction, and is a tool used to machine the inner surface of a through hole Wa in a workpiece W. The boring tool T includes a tool body 11, a tool attachment part 12, and a floating mechanism 13. The tool body 11 is a part that includes a plurality of blades 21a, and is located on the axial tip side (free end side) of the boring tool T. The tool body 11 occupies most of the boring tool T in the axial direction.

[0016] The tool body 11 includes a blade portion 21, a tip support shaft portion 22, and a base support shaft portion 23. The blade portion 21 is formed in a shaft shape. In this embodiment, the blade portion 21 has a length slightly longer than the distance between the through holes Wa at both ends of the workpiece W. The blade portion 21 has a blade 21a on its outer circumferential surface for machining the inner circumferential surface of the through hole Wa of the workpiece W. The blade portion 21 has, for example, a plurality of blades 21a arranged in the axial direction. The blade portion 21 has a number of blades 21a corresponding to the number of the through holes Wa of the workpiece W. Each of the plurality of blades 21a machines each of the plurality of through holes Wa of the workpiece W.

[0017] Furthermore, although not shown, the blade portion 21 may have a rough cutting blade 21a, a finish cutting blade 21a, a chamfering blade 21a, etc. Of course, the blade portion 21 may have only the rough cutting blade 21a, only the finish cutting blade 21a, or only the chamfering blade 21a.

[0018] The tip support shaft portion 22 is located on the axially tip side of the cutting portion 21, and constitutes a free end portion of the boring tool T. In other words, the tip support shaft portion 22 is located on the opposite side of the spindle device 3 from the cutting portion 21. The tip support shaft portion 22 has a cylindrical outer peripheral surface. The tip support shaft portion 22 has an outer diameter approximately equal to the circumscribing circle diameter of the cutting portion 21. The tip support shaft portion 22 may be the same as the circumscribing circle diameter of the cutting portion 21, or may be smaller or larger than the circumscribing circle diameter of the cutting portion 21. Furthermore, the tip support shaft portion 22 is formed with a key groove 22a extending in a direction parallel to the axial direction. The key groove 22a has a groove width (circumferential range of the groove) that gradually widens toward the tip side.

[0019] The base end support shaft portion 23 is located axially closer to the base end than the blade portion 21. In other words, the base end support shaft portion 23 is located closer to the spindle device 3 than the blade portion 21. The base end support shaft portion 23 has a cylindrical outer circumferential surface and is located coaxially with the tip support shaft portion 22. The base end support shaft portion 23 has an outer diameter larger than the circumscribing circle diameter of the blade portion 21 and also larger than the outer diameter of the tip support shaft portion 22. Furthermore, the base end support shaft portion 23 is formed with a key groove 23a extending in a direction parallel to the axial direction.

[0020] The tool mounting part 12 is located on the boring tool T closer to the axial base end than the tool body 11, and is a part that is mounted to the spindle unit 3. In detail, the tool mounting part 12 is located closer to the axial base end than the base end support shaft part 23 of the tool body 11 (to the right in FIG. 1). The tool mounting part 12 is configured to be able to replace tools with respect to the spindle unit 3, for example. The tool mounting part 12 has a known holder shape. Furthermore, the tool mounting part 12 has an engagement part (not shown) that can engage with a tool exchange arm (not shown).

[0021] The floating mechanism 13 connects the base end support shaft portion 23 of the tool body 11 and the tool mounting portion 12. The floating mechanism 13 transmits the rotation of the tool mounting portion 12 to the tool body 11, and supports the tool body 11 in a floating manner in the radial direction relative to the tool mounting portion 12. The floating mechanism 13 allows translation while maintaining the central axis of the tool body 11 and the central axis of the tool mounting portion 12 parallel to each other. The floating mechanism 13 allows, for example, movement of about several hundred μm in the radial direction. A known floating holder or the like can be used as the floating mechanism 13.

[0022] The base 2 is a base for the boring device 1 and is installed on an installation surface. A pair of guide rails 2a is provided on the upper surface of the base 2. The pair of guide rails 2a is provided so as to extend in the left-right direction in FIG.

[0023] The spindle device 3 holds and rotates the boring tool T. The spindle device 3 supports the boring tool T in a cantilever manner by holding only the base end side of the boring tool T. The spindle device 3 includes a spindle housing 31, a spindle 32, and a spindle motor 33.

[0024] The spindle housing 31 is supported movably on the guide rail 2a of the base 2. The spindle 32 is rotatably supported by the spindle housing 31. The tool attachment portion 12 of the boring tool T is detachably held at the tip of the spindle 32. The spindle motor 33 is provided in the spindle housing 31, and drives the spindle 32 to rotate. In other words, the spindle motor 33 drives the boring tool T attached to the spindle 32 to rotate. The spindle motor 33 may be provided outside the spindle housing 31, or may be provided inside the spindle housing 31.

[0025] The workpiece support table 4 supports a workpiece W to be machined by the boring tool T. The workpiece support table 4 is provided on the base 2 at a position facing the spindle device 3. The workpiece support table 4 has a support surface corresponding to the shape of the workpiece W. The workpiece support table 4 is used to place the unmachined workpiece W transported by a transport device (not shown). The transport device removes the machined workpiece W from the workpiece support table 4.

[0026] The feed device 5 is a device that moves the boring tool T relatively in the axial direction of the boring tool T with respect to the workpiece support table 4. In this embodiment, the feed device 5 moves the spindle unit 3 in the axial direction of the boring tool T with respect to the base 2, thereby moving the boring tool T with respect to the workpiece support table 4. However, the feed device 5 may be configured to move the workpiece support table 4 in the axial direction of the boring tool T with respect to the base 2. In this case, the workpiece support table 4 moves with respect to the boring tool T.

[0027] For example, a ball screw mechanism or a linear motor mechanism is applied to the feed device 5. In this embodiment, a ball screw mechanism is applied to the feed device 5. The feed device 5 includes a ball screw 41, a ball screw nut 42, and a feed motor 43. The ball screw 41 is provided on the base 2 so as to be parallel to the extending direction of the guide rail 2a, and is supported by a support member 46 rotatably attached to the base 2. The support member 46 incorporates a rolling bearing that rotatably supports the ball screw 41. The ball screw 41 and the output shaft of the feed motor 43 are rotatably connected via a coupling 47.

[0028] The ball screw nut 42 is fixed to the spindle housing 31 of the spindle device 3. The ball screw nut 42 is screwed onto the ball screw 41, and moves in the axial direction of the ball screw 41 as the ball screw 41 rotates. The feed motor 43 drives the ball screw 41 to rotate.

[0029] The support member 6 is provided near the workpiece support table 4 on the base 2. In this embodiment, the support member 6 is provided immovably on the base 2. However, when the workpiece support table 4 moves relative to the base 2, the support member 6 is provided movable relative to the base 2 together with the workpiece support table 4.

[0030] In this embodiment, the support member 6 includes a first support member 51 and a second support member 52. The first support member 51 is provided on the opposite side to the spindle unit 3 (the left side in FIG. 1) from the workpiece support table 4. The first support member 51 has a through hole into which the tip support shaft portion 22 of the boring tool T can be inserted, and supports the outer circumferential surface of the inserted tip support shaft portion 22.

[0031] The first support member 51 includes a first support body 61 and a first sleeve 62. The first support body 61 is fixed on the base 2 on the opposite side of the workpiece support table 4 from the spindle unit 3. The first sleeve 62 is rotatably supported by the first support member 51 via a bearing. The central axis of the first sleeve 62 is parallel to the central axis of the spindle 32 of the spindle unit 3 and is substantially coaxial therewith.

[0032] The first sleeve 62 has a through hole into which the tip support shaft 22 of the boring tool T can be inserted, and supports the outer peripheral surface of the inserted tip support shaft 22. The first sleeve 62 has a cylindrical inner peripheral surface. The first sleeve 62 has an inner diameter into which the tip support shaft 22 of the boring tool T can be inserted. The inner diameter of the first sleeve 62 is formed to be extremely slightly larger than the outer diameter of the tip support shaft 22 of the boring tool T.

[0033] The radial gap between the inner peripheral surface of the first sleeve 62 and the outer peripheral surface of the tip support shaft 22 of the boring tool T is small compared to the radial tolerance (maximum radial movement distance) of the floating mechanism 13. For example, the radial gap between the inner peripheral surface of the first sleeve 62 and the outer peripheral surface of the tip support shaft 22 of the boring tool T is about several tens of μm.

[0034] The first sleeve 62 has a key 62a extending in the axial direction on its inner circumferential surface. The key 62a engages with a key groove 22a of the tip support shaft 22. The groove width (circumferential range of the groove) of the key groove 22a of the tip support shaft 22 is wider on the tip side. Therefore, the key 62a can be easily inserted into the key groove 22a. Note that a key groove may be formed in the first sleeve 62, and the tip support shaft 22 of the boring tool T may have a key.

[0035] The second support member 52 includes a second support body 71, a second sleeve 72, and a locking member 73. The second support body 71 is fixed on the base 2, and on the spindle unit 3 side (the right side in FIG. 1 ) of the workpiece support table 4. The second sleeve 72 is rotatably supported by the second support member 52 via a bearing. The central axis of the second sleeve 72 is parallel to and substantially coaxial with the central axis of the spindle 32 of the spindle unit 3. In addition, the central axis of the second sleeve 72 is coaxial with the central axis of the first sleeve 62.

[0036] The second sleeve 72 has a through hole into which the base end support shaft 23 of the boring tool T can be inserted, and supports the outer peripheral surface of the inserted base end support shaft 23. The second sleeve 72 has a cylindrical inner peripheral surface. The second sleeve 72 has an inner diameter into which the base end support shaft 23 of the boring tool T can be inserted. The inner diameter of the second sleeve 72 is formed to be extremely slightly larger than the outer diameter of the base end support shaft 23 of the boring tool T.

[0037] The radial gap between the inner peripheral surface of the second sleeve 72 and the outer peripheral surface of the base end support shaft portion 23 of the boring tool T is small compared to the radial tolerance of the floating mechanism 13. For example, the radial gap between the inner peripheral surface of the second sleeve 72 and the outer peripheral surface of the base end support shaft portion 23 of the boring tool T is about several tens of μm.

[0038] The second sleeve 72 has a key 72a extending in the axial direction on its inner circumferential surface. The key 72a engages with a key groove 23a of the base end support shaft portion 23. Note that a key groove may be formed in the second sleeve 72, and a key may be provided in the base end support shaft portion 23 of the boring tool T.

[0039] The locking member 73 is provided on the second support body 71 so as to be movable forward and backward in the radial direction by an actuator. When the locking member 73 advances radially inward, the tip of the locking member 73 engages with the second sleeve 72. In this state, the locking member 73 positions the second sleeve 72 with respect to the second support body 71. When the locking member 73 is engaged, the second sleeve 72 is unable to rotate. On the other hand, when the locking member 73 retreats radially, the engagement with the second sleeve 72 is released. In this state, the second sleeve 72 is able to rotate with respect to the second support body 71.

[0040] Here, the locking member 73 is engaged with the second sleeve 72 when the base end support shaft 23 of the boring tool T is inserted into the second support member 52 and when the base end support shaft 23 is pulled out from the second support member 52. On the other hand, when the workpiece W is machined by the boring tool T, the locking member 73 is disengaged from the second sleeve 72.

[0041] (2. Configuration of the driving mechanism of the boring device 1) The configuration of the drive mechanism of the boring device 1 will be described with reference to Fig. 2. The boring device 1 includes a control device 7, a spindle motor 33, a spindle motor drive circuit 34, a feed motor 43, a feed motor detector 44, and a feed motor drive circuit 45.

[0042] As shown in FIG. 2, the control device 7 controls the spindle device 3 and the feed device 5. Specifically, the machining control unit 82 of the control device 7 controls the spindle motor 33 of the spindle device 3 when machining the workpiece W with the boring tool T. Furthermore, the insertion control unit 81 of the control device 7 controls the feed motor 43 of the feed device 5 when inserting the boring tool T into the through hole Wa of the workpiece W and the support member 6 before machining the workpiece W. That is, the insertion control unit 81 of the control device 7 controls the pre-machining feed operation by the feed device 5. Furthermore, the retreat control unit 83 of the control device 7 controls the feed motor 43 of the feed device 5 when withdrawing the boring tool T from the through hole Wa of the workpiece W and the support member 6 after machining the workpiece W. That is, the retreat control unit 83 of the control device 7 controls the post-machining return operation by the feed device 5.

[0043] Furthermore, the determination unit 85 of the control device 7 acquires, from the feed motor drive circuit 45 described later, a physical quantity (torque, drive current, etc.) equivalent to the axial load R of the boring tool T generated in the feed device 5 when the support shafts 22, 23 of the boring tool T are inserted into the support members 51, 52. In detail, the determination unit 85 of the control device 7 acquires a physical quantity equivalent to the axial load R of the boring tool T generated in the feed device 5 when the tip support shaft 22 is inserted into the first support member 51 (during insertion control) or when the base end support shaft 23 is inserted into the second support member 52 (during insertion control) by the pre-machining feed operation by the feed device 5.

[0044] Here, the load R in the axial direction of the boring tool T generated on the feed device 5 corresponds to the torque applied to the feed motor 43. Moreover, the torque applied to the feed motor 43 is proportional to the drive current of the feed motor 43. Therefore, in this embodiment, the determination unit 85 of the control device 7 acquires the drive current of the feed motor 43 (the drive current detected by the ammeter 45h) as a physical quantity equivalent to the load R.

[0045] Furthermore, only when the insertion control unit 81 is operating, the judgment unit 85 of the control device 7 judges whether or not the physical amount corresponding to the acquired load R exceeds the set value Rth. When the physical amount corresponding to the acquired load R exceeds the set value Rth, the post-judgment processing unit 86 of the control device 7 stops the pre-processing feed operation of the feed device 5. After stopping the feed operation of the feed device 5, the post-judgment processing unit 86 of the control device 7 executes post-stop processing. In addition, the set value Rth is set and stored in the threshold setting unit 84 of the control device 7. In addition, the control device 7 controls a transport device (not shown) that loads and unloads the workpiece W.

[0046] The spindle motor drive circuit 34 is a drive circuit for driving the spindle motor 33. The spindle motor drive circuit 34 drives the spindle motor 33 based on commands from the control device 7 when the insertion control unit 81, the processing control unit 82, and the retraction control unit 83 of the control device 7 perform insertion control, processing control, and retraction control.

[0047] The feed motor detector 44 is, for example, an encoder, and detects the rotation angle of the feed motor 43. The feed motor drive circuit 45 is a drive circuit for driving the feed motor 43. The feed motor drive circuit 45 drives the spindle motor 33 based on commands from the control device 7 when the insertion control unit 81, the processing control unit 82, and the retraction control unit 83 of the control device 7 perform insertion control, processing control, and retraction control.

[0048] In detail, the position counter 45i of the feed motor driving circuit 45 obtains the rotation angle of the feed motor 43 detected by the feed motor detector 44, and obtains a count value indicating the position of the rotation angle. Then, the position deviation generating unit 45a of the feed motor driving circuit 45 generates a position deviation which is the difference between the position command value obtained from the control device 7 and the output value of the position counter 45i. The position deviation corresponds to the difference between the position command value obtained from the control device 7 and the rotation angle of the feed motor 43 detected by the feed motor detector 44.

[0049] A position control processing unit 45b of the feed motor driving circuit 45 generates an output value by multiplying the generated position deviation by a position loop gain. A position speed conversion unit 45g converts the output value of the position counter 45i into a speed value. A speed deviation generating unit 45c of the feed motor driving circuit 45 generates a speed deviation based on the output value of the position control processing unit 45b and the output value of the position speed conversion unit 45g. A speed control processing unit 45d of the feed motor driving circuit 45 generates an output value by multiplying the generated speed deviation by a speed loop gain.

[0050] The ammeter 45h of the feed motor drive circuit 45 detects the drive current of the feed motor 43. The current deviation generating unit 45e of the feed motor drive circuit 45 generates a current deviation based on the output value of the speed control processing unit 45d and the drive current detected by the ammeter 45h. The current control processing unit 45f of the feed motor drive circuit 45 multiplies the generated current deviation by a current loop gain, thereby supplying the drive current of the feed motor 43.

[0051] (3. Example of a method for detecting the load R acting on the feed device 5) As described above, the ammeter 45h detects the drive current of the feed motor 43. The drive current of the feed motor 43 is proportional to the torque applied to the feed motor 43. The torque of the feed motor 43 corresponds to the load R in the axial direction of the boring tool T generated on the feed device 5. In other words, the ammeter 45h functions as a load detector that detects a physical quantity equivalent to the load R in the axial direction of the boring tool T generated on the feed device 5.

[0052] The driving current detected by the ammeter 45h is input to the determination unit 85 of the control device 7 as a physical quantity equivalent to the load R in the axial direction of the boring tool T acting on the feed device 5. That is, the determination unit 85 of the control device 7 acquires the driving current of the feed motor 43 detected by the ammeter 45h functioning as a load detector.

[0053] In the above, the case where the drive current of the feed motor 43 detected by the ammeter 45h is used as the load R in the axial direction of the boring tool T generated in the feed device 5 has been exemplified. In addition, the torque applied to the feed motor 43 calculated based on the drive current can also be used as the load R.

[0054] In addition to the above, the load R acting on the feed device 5 can also be detected in the following manner. For example, a load cell serving as a load detector may be provided between the ball screw 41 and the support member 46, and the load R in the axial direction of the boring tool T acting on the load cell via the ball screw 41 may be directly detected.

[0055] (4. Basic operation of boring device 1) The basic operation of the boring device 1 will be described with reference to Fig. 1 and Fig. 3. Before machining, the boring device 1 transitions from the state shown in Fig. 1 to the state shown in Fig. 3. Then, in the state shown in Fig. 3, the boring device 1 machines the workpiece W. Then, after machining, the boring device 1 transitions from the state shown in Fig. 3 to the state shown in Fig. 1.

[0056] First, the insertion control unit 81 of the control device 7 controls the feed device 5 to start a pre-machining feed operation of the spindle device 3 and the boring tool T. By starting the pre-machining feed operation, the tip support shaft portion 22 of the boring tool T passes through the second sleeve 72 of the second support member 52. By further performing the pre-machining feed operation, the tip support shaft portion 22 of the boring tool T passes through the multiple through holes Wa of the workpiece W. At this time, the tool main body portion 11 of the boring tool T passes through the second sleeve 72 and is inserted into the multiple through holes Wa of the workpiece W.

[0057] As the pre-machining feed operation is further performed, the tip support shaft 22 of the boring tool T is inserted into the first sleeve 62 of the first support member 51. At this time, the key 62a of the first sleeve 62 is inserted into the key groove 22a of the tip support shaft 22. Since the groove width on the tip side of the key groove 22a of the tip support shaft 22 is wide, the key 62a of the first sleeve 62 is easily inserted into the key groove 22a of the tip support shaft 22. As the key 62a of the first sleeve 62 is inserted into the key groove 22a of the tip support shaft 22, the tip support shaft 22 engages with the first sleeve 62 in the circumferential direction. In other words, the tip support shaft 22 and the first sleeve 62 are in a state in which they can rotate together.

[0058] Furthermore, at substantially the same time that the tip support shaft 22 of the boring tool T is inserted into the first support member 51, the base end support shaft 23 of the boring tool T is inserted into the second sleeve 72 of the second support member 52. Since the second sleeve 72 is engaged with the second support body 71 by the locking member 73, the circumferential positions (phase) of the key 72a of the second sleeve 72 and the key groove 23a of the base end support shaft 23 are aligned. Therefore, the key 72a of the second sleeve 72 is inserted into the key groove 23a of the base end support shaft 23.

[0059] When the key 72a of the second sleeve 72 is inserted into the key groove 23a of the base end support shaft portion 23, the base end support shaft portion 23 circumferentially engages with the second sleeve 72. In other words, the base end support shaft portion 23 and the second sleeve 72 are allowed to rotate integrally.

[0060] Here, the radial gap between the tip support shaft 22 and the first sleeve 62 and the radial gap between the base end support shaft 23 and the second sleeve 72 are very small. Therefore, unless the central axis of the tool main body 11 of the boring tool T is substantially aligned with the central axes of the first sleeve 62 and the second sleeve 72, the boring tool T cannot be inserted into the first sleeve 62 and the second sleeve 72.

[0061] The floating mechanism 13 can move the tool body 11 in the radial direction relative to the tool mounting part 12. In particular, the radial tolerance of the floating mechanism 13 is larger than the radial gap between the first sleeve 62 and the tip support shaft 22, and is also larger than the radial gap between the second sleeve 72 and the base end support shaft 23. Therefore, the operation of the floating mechanism 13 can bring the central axis of the tool body 11 of the boring tool T into a state where it substantially coincides with the central axis of the first sleeve 62 and the central axis of the second sleeve 72.

[0062] 3, the tool body 11 of the boring tool T is inserted into the through hole Wa of the workpiece W. That is, the blades 21a of the blade portion 21 of the tool body 11 of the boring tool T are positioned at positions corresponding to the through holes Wa of the workpiece W. When this state is reached, the insertion control unit 81 of the control device 7 stops the pre-machining feed operation by the feed device 5.

[0063] Next, the machining control unit 82 of the control device 7 controls the spindle device 3 to rotate the spindle device 3. As a result, the spindle 32 rotates and the boring tool T rotates. At the same time, the machining control unit 82 of the control device 7 moves the boring tool T in the axial direction by causing the feed device 5 to perform a forward or backward operation for machining. In this manner, the inner circumferential surface of the through hole Wa of the workpiece W is machined by the blade 21a of the boring tool T.

[0064] When machining is completed, the retreat control unit 83 of the control device 7 stops the rotation of the spindle device 3 and performs a post-machining return operation of the feed device 5. Then, the boring tool T is withdrawn from the workpiece W, the first support member 51, and the second support member 52, resulting in the state shown in Fig. 1. In this way, the machining cycle of the workpiece W is completed, and then the machining cycle of the next workpiece W is performed.

[0065] (5. Explanation of the setting value Rth) As described above, the control device 7 determines whether or not the load R in the axial direction of the boring tool T acting on the feeding device 5 exceeds the set value Rth, and stops the feeding operation of the feeding device 5 when the acquired load R exceeds the set value Rth. This set value Rth will be described with reference to FIG.

[0066] In Fig. 4, the horizontal axis represents the number of machining cycles of the workpiece W, and the vertical axis represents the axial load R of the boring tool T generated in the feeding device 5. For convenience, the numbers of machining cycles of the workpiece W in Fig. 4 are shown as N1 to N11. In Fig. 4, when the numbers of machining cycles are N1 to N7, the tip support shaft portion 22 is smoothly inserted into the first sleeve 62, and the base end support shaft portion 23 is smoothly inserted into the second sleeve 72. Therefore, when the numbers of machining cycles are N1 to N7, the axial load R of the boring tool T generated in the feeding device 5 exhibits a small value.

[0067] When the number of machining cycles is N8, the load R is greater than when the number of machining cycles is N1 to N7. When the number of machining cycles is N9, the load R is greater than when the number of machining cycles is N8. When the number of machining cycles is N10, the load R is greater than when the number of machining cycles is N9.

[0068] At times N8 to N10, the tip support shaft 22 is fully inserted into the first sleeve 62, and the base end support shaft 23 is fully inserted into the second sleeve 72. In other words, at times N8 to N10, during the pre-processing feed operation, the tip support shaft 22 does not get caught on the first sleeve 62 to prevent the feed operation, and the base end support shaft 23 does not get caught on the second sleeve 72 to prevent the feed operation.

[0069] When the number of machining cycles is N11, the load R increases further than when the number of machining cycles is N10. When the number of machining cycles is N11, the tip support shaft 22 is caught on the first sleeve 62 during the pre-machining feed operation, preventing the feed operation, or the base end support shaft 23 is caught on the second sleeve 72, preventing the feed operation. The load R at this time is the maximum load Rmax.

[0070] Here, the set value Rth is set to a value smaller than the load Rmax in the stuck state. In particular, the set value Rth is set to a value closer to the load R in the normal state (loads N1 to N7 in FIG. 4) than the load Rmax in the stuck state.

[0071] Furthermore, the set value Rth is set to the load R generated when the boring tool T is inserted into the first sleeve 62 and the second sleeve 72 in the machining cycle of the workpiece W that is one or more workpieces W before the workpiece W when the stuck state occurs (N11th workpiece in FIG. 4). In this embodiment, as shown by the two-dot chain line in FIG. 4, based on the results obtained from the experiment, the set value Rth is set so that the load R in the machining cycle of the workpiece W that is three workpieces before the workpiece W when the stuck state occurs exceeds the set value Rth. In other words, in FIG. 4, the load R of the N8th workpiece W exceeds the set value Rth.

[0072] (6. Processing of machining cycle by control device 7) Processing of the machining cycle by the control device 7 will be described mainly with reference to Fig. 5, and also with reference to Fig. 1 and Fig. 4 as appropriate. A case will be described in which the boring device 1 performs continuous machining cycles for a plurality of workpieces W. Also, it is assumed that the boring tool T is attached to the spindle device 3.

[0073] The control device 7 controls a conveying device (not shown) to load the workpiece W (workpiece loading step ST1). As shown in FIG. 1, the loaded workpiece W is placed on a workpiece support table 4.

[0074] Next, the insertion control unit 81 of the control device 7 controls the feed device 5 to start a pre-machining feed operation of the spindle device 3 and the boring tool T (pre-machining feed operation start step ST2). That is, an operation for inserting the boring tool T into the through hole Wa of the workpiece W, the first support member 51, and the second support member 52 is started.

[0075] When the pre-processing feed operation is started, the determination unit 85 of the control device 7 determines whether the acquired load R exceeds the set value Rth (load determination step ST3). If the load R during the pre-processing feed operation is equal to or less than the set value Rth (ST3: No), the pre-processing feed operation is continued until the processing start position is reached (processing start position determination step ST4). In other words, if the processing start position has not been reached (ST4: No), the load determination step ST3 is executed again. On the other hand, if the processing start position has been reached (ST4: Yes), the insertion control unit 81 of the control device 7 ends the pre-processing feed operation (pre-processing feed operation end step ST5).

[0076] Next, the control device 7 moves the locking member 73 of the second support member 52 backward in the radial direction to release the engagement between the locking member 73 and the second sleeve 72 (second support member unlocking step ST6). That is, the second sleeve 72 becomes rotatable relative to the second support body 71.

[0077] Next, the machining control unit 82 of the control device 7 controls the spindle device 3 to rotate the boring tool T, and controls the feed device 5 to move the boring tool T in the axial direction. In this manner, the control device 7 machines the through hole Wa of the workpiece W with the boring tool T (machining step ST7). When machining is completed, the machining control unit 82 of the control device 7 controls the spindle device 3 to stop the rotation of the boring tool T, and controls the feed device 5 to stop the axial position of the boring tool T.

[0078] Then, when the control device 7 finishes the processing, it advances the locking member 73 of the second support member 52 radially inward to engage the locking member 73 with the second sleeve 72 (second support member locking step ST8). That is, the second sleeve 72 becomes unrotatable with respect to the second support body 71.

[0079] Next, the retreat control unit 83 of the control device 7 controls the feed device 5 to perform a post-machining return operation of the spindle device 3 and the boring tool T (post-machining return operation step ST9). That is, the boring tool T is pulled out from the through hole Wa of the workpiece W, the first support member 51, and the second support member 52 to the state shown in Fig. 1. Next, the control device 7 controls a transfer device (not shown) to carry out the machined workpiece W (workpiece carrying-out step ST10).

[0080] Next, the control device 7 judges whether or not the next workpiece W exists, and if the next workpiece W exists (next workpiece presence / absence judging step ST11: Yes), the process is repeated from the workpiece carrying-in step ST1. On the other hand, if the next workpiece W does not exist (ST11: No), the control device 7 ends the process.

[0081] Here, in the load determination step ST3, if the load R during the pre-machining feed operation exceeds the set value Rth (ST3: Yes), the post-determination processing unit 86 of the control device 7 stops the pre-machining feed operation (feed operation stopping step ST12). In Fig. 4, since the load R exceeds the set value Rth during the pre-machining feed operation for the N8th workpiece W, the pre-machining feed operation is stopped.

[0082] Furthermore, the post-determination processing unit 86 of the control device 7 performs post-stop processing after stopping the pre-machining feed operation (post-stop processing step ST13). The post-stop processing includes, for example, notifying a manager or an operator that the load R has exceeded the set value Rth, displaying the information on a display device (not shown) constituting the boring device 1, displaying the information on a management device (not shown), sounding an alarm, and the like.

[0083] Then, the control device 7 ends the process after performing the post-stop processing. Here, when the control device 7 performs the post-stop processing, the worker performs maintenance work on the boring tool T, the first sleeve 62, and the second sleeve 72. For example, when foreign matter such as cutting chips is present, the worker performs work to remove the cutting chips. When scratches are present on the surfaces of the tip support shaft portion 22, the base end support shaft portion 23, the first sleeve 62, and the second sleeve 72 of the boring tool T, the worker performs work to correct the object. After the worker has finished the work, the process of FIG. 5 is performed again, thereby allowing continuous machining of the workpiece W.

[0084] (7. Effects) As described above, it has been found that during the operation of inserting the boring tool T into the first support member 51 and the second support member 52, the axial load R on the boring tool T by the feed device 5 begins to increase before the support shaft portions 22, 23 of the boring tool T become caught on the sleeves 62, 72 of the support members 51, 52.

[0085] Therefore, according to the boring device 1, the control device 7 acquires the axial load of the boring tool T generated on the feeding device 5 when the support shaft portions 22, 23 are inserted into the support members 51, 52 by the pre-processing feed operation of the feeding device 5. Then, the control device 7 stops the pre-processing feed operation by the feeding device 5 when the acquired load R exceeds a set value Rth.

[0086] The state in which the axial load R generated in the feeding device 5 becomes the set value Rth can be the state before the support shaft portions 22, 23 of the boring tool T get caught on the support members 51, 52. Therefore, the feeding operation of the feeding device 5 can be stopped before the support shaft portions 22, 23 of the boring tool T get caught on the support members 51, 52.

[0087] Then, the worker can pull out the boring tool T from the support members 51, 52 by performing a return operation after stopping the pre-machining feed operation by the feed device 5. After that, the worker performs maintenance work on the boring tool T and the support members 51, 52. This maintenance work is much easier than the correction work for the state in which the support shaft portions 22, 23 of the boring tool T are caught on the support members 51, 52. Therefore, the number of work steps can be significantly reduced.

[0088] (8. Modifications) In the embodiment described above, the judgment unit 85 performs the comparison judgment while the insertion control unit 81 is operating. The judgment unit 85 may perform the comparison judgment not over the entire range in which the insertion control unit 81 is operating, but during the range from immediately before insertion until the insertion is in progress.

[0089] The configuration of the boring apparatus 1 in this case will be described with reference to Fig. 6. The configuration of the boring apparatus 1 shown in Fig. 6 differs from the configuration of the boring apparatus 1 shown in Fig. 2 only in the feed motor drive circuit 45.

[0090] A position range of the spindle unit 3 from a position immediately before the boring tool T is inserted into the first support member 51 and the second support member 52 to a position where insertion is completed is set and stored in the setting unit 45j of the feed motor drive circuit 45. Next, the comparison unit 45k compares the current position of the spindle unit 3 obtained by the position counter 45i with the position range stored in the setting unit 45j. When the current position of the spindle unit 3 obtained by the position counter 45i is located within the position range of the spindle unit 3 stored in the setting unit 45j, the gate unit 45m opens the gate so that a signal from the ammeter 45h is sent to the determination unit 85.

[0091] When the determination unit 85 receives a signal (load R) from the gate unit 45m, the determination unit 85 determines whether the received load R exceeds the set value Rth. In other words, the determination unit 85 does not perform a determination from the start of the pre-processing feed operation until immediately before the boring tool T is inserted into the first support member 51 and the second support member 52.

[0092] Here, the torque (or drive current) in the feed motor 43 becomes very large when the spindle device 3 starts to move, that is, immediately after the spindle device 3 starts to move from a stopped state. The start of movement of the spindle device 3 is equal to the start of movement of the feed motor 43. In the above process, since the start of movement of the spindle device 3 is excluded from the judgment target, it is possible to reliably judge the signs that the support shaft portions 22, 23 of the boring tool T will get caught on the support members 51, 52. [Explanation of symbols]

[0093] 1 Boring device 3 Spindle device 4 Workpiece support 5 Feeder 6 Support material 7 Control device 11 Tool body 12 Tool attachment section 13 Floating mechanism 21 Blade 21a blade 22 Tip support shaft 23 Base end support shaft 51 First support member 52 Second support member R load Rth setting value T Boring Tool W Workpiece Wa Through hole

Claims

1. A boring tool having a shaft-shaped blade portion having a blade on an outer circumferential surface and a support shaft portion located at least on the axial tip side of the blade portion; A spindle device that holds and rotates the boring tool; a workpiece support table for supporting a workpiece to be machined by the boring tool; a feed device that moves the boring tool relative to the workpiece support in an axial direction of the boring tool; a support member that is provided on at least the opposite side of the spindle device from the workpiece support table, has a through hole into which the support shaft portion of the boring tool can be inserted, and supports an outer peripheral surface of the inserted support shaft portion; a control device that acquires a load in an axial direction of the boring tool generated in the feed device when the support shaft portion is inserted into the support member by a feed operation of the feed device, and stops the feed operation of the feed device when the acquired load exceeds a set value; Equipped with the set value is a value smaller than a load generated in the feed device when the feed device is driven in a state in which the support shaft portion is axially hooked on the support member, the control device, when performing a machining cycle for a plurality of the workpieces in succession, executes an operation of inserting the boring tool into the support member before machining each of the workpieces; The set value is set to a load generated when the boring tool is inserted into the support member in a machining cycle of the workpiece that is one or more pieces before the workpiece when the support shaft portion is caught in the axial direction of the support member. Boring device.

2. The boring tool comprises: The blade portion, a tip support shaft portion as the support shaft portion, the tip support shaft portion being located on the axial tip side of the blade portion; a base end support shaft portion located on the base end side of the axial direction relative to the blade portion; Equipped with The support member is a first support member provided on the opposite side of the spindle device from the workpiece support table, the first support member having a through hole into which the tip support shaft portion of the boring tool can be inserted, and supporting an outer peripheral surface of the inserted tip support shaft portion; a second support member provided closer to the spindle device than the workpiece support table, having a through hole into which the base end support shaft portion of the boring tool can be inserted, and supporting an outer peripheral surface of the inserted base end support shaft portion; Equipped with The boring device according to claim 1, wherein the control device acquires an axial load of the boring tool generated in the feeding device when the tip support shaft portion is inserted into the first support member or when the base end support shaft portion is inserted into the second support member, and stops the feeding operation of the feeding device when the acquired load exceeds the set value.

3. The boring tool comprises: a tool body including the blade portion and the support shaft portion; A tool mounting portion that is mounted on the spindle device; a floating mechanism that supports the tool body in a radial direction relative to the tool mounting portion; 3. The boring device according to claim 1 or 2, comprising:

4. The boring device according to claim 3 , wherein a radial gap between the support member and the support shaft portion is set to be smaller than a radial allowable range of the floating mechanism.

Images