Workpiece conveying unit

Abstract

To provide a workpiece conveying unit capable of reducing a product production cost and a maintenance cost of a machine tool by simplifying a structure without using a coolant as a working fluid and simplifying a process after delivering a workpiece.SOLUTION: The workpiece conveying unit includes a shank part 21 attached to a main spindle part of a machine tool and an arm portion 32 projecting in a vertical direction below the shank part 21. The arm portion 32 is provided with a workpiece support seat surface 34. The workpiece support seat surface 34 comes into contact with an inner annular flat surface of a workpiece and supports the workpiece by supporting the contacted portion from below. Further, the arm portion 32 is provided with a coolant discharge portion 90 for discharging a coolant toward the workpiece supported by the workpiece support seat surface 34, and a coolant flow passage 93 for allowing the coolant supplied from a spindle portion side to flow to the coolant discharge portion 90.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a workpiece transport unit that is attached to a spindle of a machine tool. [Background technology]

[0002] In machine tools such as machining centers, workpieces are sometimes loaded and unloaded using a workpiece transport unit attached to the spindle. A known example of such a workpiece transport unit is a chuck unit that uses coolant as a working fluid to operate a chuck (see Patent Document 1).

[0003] After a workpiece is removed from a machine tool using such a chuck unit, chips generated during machining such as cutting and drilling adhere to or accumulate on the workpiece. Since the chips must be removed before the workpiece can be processed in the next step, a chip removal step is provided after the workpiece is removed, and a cleaning device specifically designed for chip removal is used in this step (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-66114 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-45801 Summary of the Invention [Problem to be solved by the invention]

[0005] The chuck unit described in Patent Document 1 includes a mechanism for operating the chuck using coolant. This increases the complexity and size of the internal structure of the unit, thereby increasing the manufacturing cost of the chuck unit. Furthermore, coolant deteriorates with long-term, continuous use. Continued use of degraded coolant leads to deterioration of the seals installed in the flow passages. Degraded seals cause coolant leakage, affecting the operation of the chuck. To prevent this, periodic seal replacement is required, raising concerns about increased machine tool maintenance costs. These concerns are not limited to the chuck device described in Patent Document 1; they also arise when coolant is used as the working fluid for a mechanism for holding a workpiece.

[0006] Furthermore, if a chip removal process using a cleaning device is required after the workpiece is removed from the machine tool, the number of manufacturing steps increases accordingly, which, combined with the cost of installing the manufacturing equipment, increases the cost of manufacturing the product.

[0007] The present invention has been made in consideration of the above-mentioned situation, and aims to provide a work transport unit that can reduce product manufacturing costs and machine tool maintenance costs by having a simple configuration without using coolant as a working fluid and by simplifying the processes after the workpiece is removed. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides: A workpiece transport unit comprising a shank portion attached to a spindle portion of a machine tool, and transporting a workpiece while attached to the spindle portion, an arm portion provided on the shank portion; a work support seat provided on the arm portion and abutting against a contacted portion of the work to support the contacted portion, thereby supporting the work; a coolant discharge portion provided on the arm portion and configured to discharge coolant toward the workpiece supported by the workpiece support seat; a coolant flow passage that allows coolant supplied from the spindle portion side to flow to the coolant discharge portion when the coolant supply port is attached to the spindle portion; It is equipped with: [Effects of the Invention]

[0009] According to the present invention, after being attached to the spindle of a machine tool, the work support seat abuts against the abutted portion of the workpiece, supporting the abutted portion from below, thereby supporting the workpiece. By further moving the work transport unit through the operation of the spindle, the workpiece can be transported to the desired position. In this case, the workpiece is not held by a mechanism using coolant as the working fluid as in conventional technology; instead, the abutted portion of the workpiece is simply supported from below by the work support seat. Therefore, there is no need to circulate coolant for workpiece holding within the unit, simplifying the structure and reducing product manufacturing costs and machine tool maintenance costs.

[0010] Furthermore, when transporting a workpiece after it has been machined, such as by cutting or drilling, by discharging coolant from the coolant discharge port onto the workpiece supported by the workpiece support seat, it is possible to wash away chips that have adhered to or accumulated on the workpiece and clean the workpiece. If chips can be removed at the same time as the machined workpiece is transported, it may be possible to eliminate or simplify the chip removal process using a cleaning device, which also further reduces product manufacturing costs. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. [Figure 2] FIG. 10 is a front view of the differential case being transported by the work transport unit. [Figure 3] FIG. [Figure 4] AA cross section in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view showing a state in which the differential case is positioned in phase; [Figure 6] FIG. 10 is a top view of the differential case being transported by the work transport unit. [Figure 7] FIG. [Figure 8] FIG. 10 is an explanatory diagram illustrating a state in which the differential case before machining is lifted by the workpiece transport unit. [Figure 9] FIG. 10 is an explanatory diagram illustrating a state in which the differential case before machining is transported and placed on a machining jig. [Figure 10] FIG. 10 is an explanatory diagram illustrating how the machined differential case is lifted by the workpiece transport unit. [Figure 11] FIG. 10 is an explanatory diagram illustrating how the machined differential case is transported by the work transport unit and placed at the ejection position. DETAILED DESCRIPTION OF THE INVENTION

[0012] A workpiece transport unit according to an embodiment of the present invention will now be described with reference to the drawings. The workpiece transport unit of this embodiment is attached to a spindle of a machine tool such as a machining center, and transports a differential case.

[0013] (Basic configuration) First, the basic configuration will be described. As shown in FIG. 1, the work transport unit 10 is configured by attaching a work transport tool 30 to one end of a holder portion 20. In the following, the side of the holder portion 20 to which the work transport tool 30 is attached will be referred to as the lower side, and the opposite side will be referred to as the upper side. The holder portion 20 has a shank portion 21. The shank portion 21 is generally conical and tapered upward. A clamp portion 22 is provided at the lower end of the shank portion 21. The clamp portion 22 is gripped by an automatic tool changer (not shown), making it possible to exchange the work transport unit 10 for a tool unit (not shown). A pull stud 23 is provided at the upper end of the holder portion 20.

[0014] The workpiece carrier 30 comprises a shaft portion 31, an arm portion 32, and a workpiece support plate portion 33. The shaft portion 31 is columnar and is attached to the holder portion 20 below the holder portion 20. The holder portion 20 and the shaft portion 31 have the same central axis C1. The arm portion 32 protrudes from the shaft portion 31 at the lower end portion thereof in a direction perpendicular to the central axis C1. The arm portion 32, which is substantially flat, is attached to the shaft portion 31 with its plate surface facing upward and horizontal.

[0015] The work support plate portion 33 is provided at the protruding end of the upper surface of the arm portion 32, with the plate surface facing up and down. The work support plate portion 33 is disk-shaped, and an abutment surface (an inner annular plane 49 (see FIG. 2) described below) of the work W is placed on its upper surface, so that the work W is supported in a state of being supported from below by the work support plate portion 33. Therefore, the upper surface of the work support plate portion 33 serves as a work support seat surface 34 that serves as a work support seat portion. Like the upper surface of the arm portion 32, the work support seat surface 34 is horizontal and perpendicular to the central axis C1 of the holder portion 20 and the shaft portion 31. The work support seat surface 34 corresponds to the work support seat portion.

[0016] The basic configuration of the work transport unit 10 is as described above, and transport of the work W using this work transport unit 10 is performed as follows: The work transport unit 10 is stored in a tool magazine (not shown) like other tool units of the machine tool, and when transport of the work W is required, the holder part 20 is attached to the spindle part (not shown) to transport the work W.

[0017] Before describing the transportation of the workpiece W in more detail, the configuration of the differential case 40, which is the workpiece W to be transported by the workpiece transport unit 10, will be briefly described with reference to FIG.

[0018] As shown in FIG. 2, the differential case 40 has a gear accommodating portion 41 that accommodates gears. The gear accommodating portion 41 corresponds to the main body of the workpiece W and has an accommodating space 42 that accommodates the gears and an accommodating wall portion 43 that forms the accommodating space 42. The accommodating space 42 corresponds to the inner space. Two relatively large window portions 44 are provided in the accommodating wall portion 43, and the window portions 44 face each other in a direction perpendicular to the plane of the paper in FIG. 2 (see FIG. 6). Each window portion 44 penetrates the inside and outside of the gear accommodating portion 41. In the gear accommodating portion 41, the central axis C2 thereof is in the direction of the rotational axis of a shaft (not shown).

[0019] The gear accommodating portion 41 is provided with a first shaft insertion portion 45 that protrudes axially from the gear accommodating portion 41 at one end on the central axis C2. The first shaft insertion portion 45 is generally cylindrical and extends axially. The first shaft insertion portion 45 has a first cylindrical interior 46 that communicates with the accommodating space 42. The first cylindrical interior 46 has a first communication port 47 that opens toward the accommodating space 42 and a first open port 48 that opens at the end opposite the gear accommodating portion 41. An inner annular flat surface 49 is provided on the opening periphery of the first communication port 47. The inner annular flat surface 49 is perpendicular to the central axis C2 and is formed over the entire periphery.

[0020] The gear accommodating portion 41 is provided with a flange portion 50 at the other end on its central axis C2, protruding radially from the outer periphery of the gear accommodating portion 41. The flange portion 50 is annular (see FIG. 6 ) and has a number of equally spaced bolt holes 51. A second shaft insertion portion 52 is provided at the other end beyond the flange portion 50, protruding axially from the flange portion 50. The second shaft insertion portion 52 is also substantially cylindrical and has the same central axis C2 as the gear accommodating portion 41 and the first shaft insertion portion 45. The second shaft insertion portion 52 has a second cylindrical interior 53 as a cylindrical space that communicates with the accommodating space 42. The second cylindrical interior 53 has a second communication port 54 that opens toward the accommodating space 42 and a second open port 55 that opens at the end opposite the flange portion 50.

[0021] As shown in FIG. 2 , the work transport unit 10 supports the differential case 40 with the central axis C2 of the differential case 40 oriented vertically, the first shaft insertion portion 45 on the upper side, and the second shaft insertion portion 52 on the lower side. In this case, the inner annular plane 49 is horizontal and provided on the ceiling side of the accommodation space 42. The protruding end of the arm portion 32 and the work support plate portion 33 are inserted into the accommodation space 42 from one of the pair of windows 44, and the work support seat surface 34 abuts against the inner annular plane 49, which serves as the abutment portion. With the inner annular plane 49 placed on the work support seat surface 34, the work transport unit 10 is moved upward, thereby lifting the differential case 40 onto the work transport unit 10. Then, the work transport unit 10 is moved, and the differential case 40 is transported to the required location. After the transfer, the workpiece support seat surface 34 is separated from the inner annular plane 49 , and the protruding end of the arm portion 32 and the workpiece support plate portion 33 are removed from the window portion 44 .

[0022] (Additional configuration) In addition to the above-described basic configuration and its functions, the workpiece transport unit 10 has the following additional configuration. As shown in Fig. 1, the additional configurations include a centering boss 60 that performs centering of the differential case 40 (see Fig. 2) placed on the workpiece support seat surface 34, a phase positioning device 70 that positions the rotational position (rotational phase) of the differential case 40, and a coolant discharge unit 90 that discharges coolant toward the differential case 40. Next, each of these additional configurations will be described in order.

[0023] (Centering boss 60) The centering boss 60 corresponds to a positioning portion for determining the placement position of the differential case 40 (workpiece W) when it is placed on the arm portion 32. The centering boss 60 is provided on the workpiece support seating surface 34 so as to protrude upward from the workpiece support seating surface 34. The centering boss 60 has a shape in which two cylindrical portions 61, 62 of different diameters are stacked. One is a first cylindrical portion 61 provided on the workpiece support seating surface 34, and the other is a second cylindrical portion 62 provided on the first cylindrical portion 61 and having a smaller diameter than the first cylindrical portion 61. Both cylindrical portions 61, 62 have the same central axis C3 as the workpiece support seating surface 34. Because the diameter of the first cylindrical portion 61 is smaller than the diameter of the workpiece support plate portion 33, the workpiece support seating surface 34 is provided in an annular shape around the first cylindrical portion 61.

[0024] As shown in FIG. 2, the first shaft insertion portion 45 of the differential case 40, which is the workpiece W, is divided into two portions with different diameters in the first cylindrical interior 46. One is a large diameter portion 56 provided on the gear accommodating portion 41 side, and the other is a small diameter portion 57 whose diameter is smaller than the large diameter portion 56. The first cylindrical portion 61 of the centering boss 60 corresponds to the large diameter portion 56, and the second cylindrical portion 62 corresponds to the small diameter portion 57. When the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat surface 34, the second cylindrical portion 62 is inserted into the small diameter portion 57, and the first cylindrical portion 61 is inserted into the large diameter portion 56.

[0025] The inner diameter of each of the cylindrical portions 61, 62 and the corresponding first cylindrical interior 46 are set to be approximately the same. Therefore, when each of the cylindrical portions 61, 62 is inserted into the first shaft insertion portion 45, the outer peripheral surface of the second cylindrical portion 62 abuts against the small diameter portion 57, and the outer peripheral surface of the first cylindrical portion 61 abuts against the large diameter portion 56. As a result, the central axis C2 of the first shaft insertion portion 45, i.e., the central axis C2 of the differential case 40, coincides with the central axis C3 of the workpiece support seating surface 34. In this state, the differential case 40 is placed on the workpiece support seating surface 34 and centered. Note that after the differential case 40 is transported to a predetermined location, the centering boss 60 is removed from the first shaft insertion portion 45. Therefore, the cylindrical portions 61, 62 of the centering boss 60 are inserted into and removed from the first shaft insertion portion 45. Therefore, a predetermined tolerance is provided between the outer periphery of each of the cylindrical portions 61, 62 and the inner surface of the first cylindrical interior .

[0026] (Phase positioning device 70) As shown in FIGS. 1 and 3, the phase positioning device 70 is provided on the arm section 32 closer to the shaft section 31 (on the side opposite the arm protruding side) than the workpiece support plate section 33. The phase positioning device 70 has a swinging section 71 and a swinging follower section 72. As shown in FIG. 3, the swinging section 71 is provided on the arm section 32 at the center in the width direction of the arm section 32 (a direction horizontal and perpendicular to the protruding direction). The swinging section 71 has a substantially rectangular parallelepiped shape, with its longitudinal direction facing the protruding direction, and is disposed in a swinging section accommodating space 35 provided in the arm section 32. The arm protruding side of the swinging section 71 extends inward beyond the outer periphery of the workpiece support plate section 33, and the workpiece support plate section 33 is provided with a recess 33a recessed inward from the outer edge to avoid interference with the swinging section 71.

[0027] The swinging portion 71 swings around a pivot 73 extending along the width direction of the arm portion 32. The swinging follower portion 72 is provided on the swinging portion 71 and is integrated with the swinging portion 71. Therefore, the swinging follower portion 72 follows the movement of the swinging portion 71. The long swinging follower portion 72 is disposed above the arm portion 32 so that its longitudinal direction is parallel to the width direction of the arm portion 32. The swinging follower portion 72 is formed to be slightly longer than the width of the arm portion 32.

[0028] The mechanism by which the swinging portion 71 swings is as follows. As shown in Fig. 4, the swinging portion 71 is provided with a shaft insertion hole 74 through which a pivot shaft 73 passes, and a bushing 75 is interposed between the swinging portion 71 and the pivot shaft 73. This allows the swinging portion 71 to swing around the pivot shaft 73. The pivot shaft 73 is provided on the side of the swinging portion 71 opposite to the arm protrusion side, and a rotation restricting plate 36 attached to the underside of the arm portion 32 is provided below the swinging portion 71. Spring accommodating portions 37, 76 that communicate with each other are provided on the underside of the swinging portion 71 and the upper surface of the rotation restricting plate 36, respectively, on the arm protrusion side of the pivot shaft 73. A coil spring 77 that straddles both spring accommodating portions 37, 76 is accommodated in a compressed state. The upper end of the coil spring 77 abuts against the bottom surface 76a (upper surface) of the spring accommodating portion 76 provided in the swinging portion 71, and the lower end abuts against the bottom surface 37a (lower surface) of the spring accommodating portion 37 provided in the rotation restricting plate .

[0029] Therefore, the arm protruding side end of the swinging part 71 is biased in a clockwise rotating direction in the drawing, and is held in a state where an upper surface 71a of the arm protruding side end is positioned above the work support seat surface 34. A bolt 78 is provided at the arm protruding side end of the swinging part 71, and a bolt head 79 is provided at the arm protruding side end of the upper surface 71a so as to protrude from the upper surface 71a.

[0030] When a force is applied that presses down the arm protruding side end of the swinging part 71 against the biasing force of the coil spring 77, the swinging part 71 rotates counterclockwise in the drawing about the pivot shaft 73. As a result, the arm protruding side end of the swinging part 71 abuts against the rotation restricting plate 36, as shown in FIG. 5, and further rotation is restricted. The force that presses down the arm protruding side end of the swinging part 71 is applied when the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seating surface 34. When the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seating surface 34, the upper surfaces of the bolt heads 79 provided at the arm protruding side end abut against the inner annular flat surface 49 in a horizontal position.

[0031] When the inner annular flat surface 49 moves away from the workpiece support seat surface 34, the arm protruding side end of the oscillating part 71 is again urged in the direction of clockwise rotation in the drawing, and as shown in Figure 4, the arm protruding side of the upper surface 71a is held in a state where it is positioned above the workpiece support seat surface 34. In this way, the oscillating part 71 has a basic state where the arm protruding side of its upper surface 71a is positioned above the workpiece support seat surface 34, and it oscillates between this basic state and a pressed-down state where the arm protruding side abuts against the rotation restricting plate 36 and the upper surface of the bolt head 79 is horizontal.

[0032] The swing follower 72 follows the swing of the swinging part 71. As shown in FIG. 4, the swing follower 72 is connected to the swinging part 71 by a connecting part 80 that protrudes upward from the upper end of the swinging part 71. As shown in FIG. 5, the swing follower 72 has a pair of end faces 81 that are perpendicular to the protruding direction of the arm part 32 when the swinging part 71 is in the pressed-down state. The swing follower 72 has a protruding part 82 that protrudes from the end face 81 on the arm protruding side of the pair of end faces 81 toward the arm protruding side. As shown in FIG. 3, the protruding part 82 is provided at both ends of the swing follower 72 in the longitudinal direction. All of the protruding parts 82 are set to protrude the same amount from the end face 81 on the arm protruding side. The protruding part 82 is formed by a bolt 83 that protrudes from the end face 81 on the arm protruding side of the swing follower 72.

[0033] As shown in Fig. 4, when the swinging part 71 is in the basic state, the protrusions 82 of the swinging follower part 72 protrude obliquely upward in the arm protrusion direction from the end face 81. When the inner annular flat surface 49 of the differential case 40 is placed on the work support seat surface 34 and the swinging part 71 is in the pressed-down state, as shown in Fig. 5, both protrusions 82 provided on the swinging follower part 72 protrude horizontally and the protruding ends abut against the outer surface of the differential case 40. As a result, with the inner annular flat surface 49 of the differential case 40 placed on the work support seat surface 34, the rotational phase of the differential case 40 about the central axis C2 is positioned at a specific phase.

[0034] This positioning will be explained in more detail. First, as shown in Figure 6, the differential case 40 has a storage wall 43 that forms the gear storage portion 41, and the storage wall 43 has horizontally elongated window upper edge surfaces 58 above the pair of windows 44 among the peripheral edges that form the pair of windows 44. When the differential case 40 is viewed from above, the pair of window upper edge surfaces 58 each extend in a direction perpendicular to the direction in which the window portions 44 face each other, and are substantially parallel to the central axis C2 of the differential case 40 and are also parallel to each other.

[0035] As shown in FIGS. 5 and 6 , when the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat 34 and the swinging portion 71 is in the pressed-down state, the protruding ends of the two protrusions 82 provided on the swinging follower 72 abut against the pair of window upper edge surfaces 58 on the side opposite the arm protrusion. This abutment presses the window upper edge surface 58 on the side opposite the arm protrusion at two points spaced apart by approximately the width of the arm portion 32 toward the arm protrusion direction. As a result, when viewed from above, the differential case 40 with the inner annular flat surface 49 placed on the workpiece support seat 34 is positioned so that the window upper edge surfaces 58 are perpendicular to the protruding direction of the arm portion 32, as shown in FIG. 6 . From this position, the differential case 40 is prevented from rotating about its central axis C2. As a result, the differential case 40 is positioned at a specific rotational phase among the rotational phases about its central axis C2.

[0036] In the phase positioning device 70, the swinging portion 71, more specifically, the arm protruding end portion thereof corresponds to the pressed-down portion, and the pair of protruding portions 82 provided on the swinging follower portion 72 correspond to the abutment portions that abut against the workpiece W and position its rotational phase.

[0037] (coolant discharge part 90) As shown in FIG. 1, the coolant discharge portion 90 has a first discharge port 91 and a second discharge port 92. As also shown in FIG. 7, one first discharge port 91 is provided below the workpiece support plate 33, on the central axis C3 of the workpiece support plate 33 and the centering boss 60. The first discharge port 91 opens downward in a direction parallel to the central axis C1 of the holder portion 20 and the shaft portion 31. The first discharge port 91 has a larger opening than the second discharge port 92, allowing for the discharge of a larger amount of coolant. When the inner annular flat surface 49 is placed on the workpiece support seat surface 34, as shown in FIG. 2, the first discharge port 91 opens downward in the vertical direction and is located above the second communication port 54 in the second cylinder interior 53.

[0038] As shown in FIGS. 1 and 7 , the second outlets 92 are provided in multiples on the protruding end side of the arm portion 32 at both widthwise ends of the arm portion 32. In this embodiment, five second outlets 92 are provided on each end. The multiple second outlets 92 provided at each end are arranged in a row at equal intervals along the protruding direction of the arm portion 32. As shown in FIG. 2 , the areas where the second outlets 92 are provided form inclined surfaces 38 that slope outward. Therefore, the second outlets 92 open diagonally downward and outward. The second outlets 92 are smaller in size than the first outlets 91, and the amount of coolant discharged from each second outlet 92 is smaller than the amount discharged from the first outlet 91. However, by discharging from multiple locations, coolant can be discharged over a wide area.

[0039] As shown in FIG. 1, the pull stud 23 provided at the upper end of the holder portion 20 is provided with an inlet 24 through which coolant is introduced. The inlet 24 opens upward on the central axis C1 of the holder portion 20. A coolant flow passage 93 is formed inside each of the holder portion 20, the shaft portion 31, and the arm portion 32 (see also FIG. 7). The coolant flow passage 93 is connected from the inlet 24 to a first discharge port 91 and a second discharge port 92, respectively. Therefore, when coolant is supplied to the inlet 24 with the workpiece transport unit 10 attached to the spindle portion of the machine tool, the coolant flows through the coolant flow passage 93 and reaches the first discharge port 91 and the second discharge port 92, and is discharged from each of the discharge ports 91, 92.

[0040] When the inner annular flat surface 49 is placed on the workpiece support seat surface 34, the first discharge port 91 discharges coolant downward toward the inside of the second cylinder interior 53. Meanwhile, the multiple second discharge ports 92 discharge coolant toward a wide area below the inner wall portion 43a of the accommodation wall portion 43 that forms the accommodation space 42. The flow of coolant discharged at a relatively high flow rate from the first discharge port 91, combined with the flow of coolant discharged from the multiple second discharge ports 92 and rebounding off the inner wall portion 43a, creates a powerful flow of coolant in the accommodation space 42, which is discharged from the window portion 44 and the second open port 55 of the second cylinder interior 53.

[0041] (Work transport procedure) The workpiece transport unit 10 has the above-described basic configuration and additional configuration. Next, the transport of the differential case 40 using the workpiece transport unit 10 in a machine tool will be described. The description will be divided into a case where the differential case 40 is introduced into the processing position before being machined by the machine tool, and a case where the differential case 40 is removed (discharged) from the processing position after being machined. Both transport operations are controlled by controlling the drive of the main shaft to which the workpiece transport unit 10 is attached. Note that in Figures 8 to 11 which explain the transport procedure, the holder portion 20 and the shaft portion 31 are not shown.

[0042] First, a case where the workpiece transport unit 10 is used to load the unmachined differential case 40 into the machining position will be described.

[0043] As shown in FIG. 8(a), the unmachined differential case 40 is placed on the workpiece stand 101 at a predetermined pre-loading position. The differential case 40 placed on the workpiece stand 101 has its central axis C2 aligned vertically, the first shaft insertion portion 45 on the upper side, and the second shaft insertion portion 52 on the lower side. The direction in which the pair of windows 44 face each other generally coincides with the protruding direction of the arm portion 32. However, since the centering and rotational phase positioning of the differential case 40 are performed during transportation, precision in the orientation of the windows 44 is not required. With the differential case 40 thus placed, the protruding end of the arm portion 32 is inserted into the accommodation space 42 of the gear accommodation portion 41 through the window portion 44 on the side where the workpiece transport unit 10 is located. The insertion is continued until the centering boss 60 is positioned below the first shaft insertion portion 45, and then the workpiece transport unit 10 is moved upward.

[0044] 8(b), the second cylindrical portion 62 of the centering boss 60 is inserted into the small diameter portion 57 of the first cylindrical interior 46 of the first shaft insertion portion 45, and the first cylindrical portion 61 is inserted into the large diameter portion 56, so that the workpiece support seating surface 34 abuts against the inner annular flat surface 49. If the workpiece transport unit 10 is further moved upward from there, the inner annular flat surface 49 is placed on the workpiece support seating surface 34, and the differential case 40 is lifted by the workpiece transport unit 10. At this time, the outer peripheral surface of the first cylindrical portion 61 abuts against the large diameter portion 56 of the first cylindrical interior 46, and the outer peripheral surface of the second cylindrical portion 62 abuts against the small diameter portion 57, so that the central axis C2 of the differential case 40 coincides with the central axis C3 of the workpiece support seating surface 34, thereby centering the differential case 40. This positions the differential case 40 on the arm portion 32.

[0045] 5 and 6, when the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat surface 34, the inner annular flat surface 49 presses down on the workpiece protruding side end of the swinging portion 71 of the phase positioning device 70, causing the swinging portion 71 to swing from the base state to the pressed-down state. Accordingly, the protruding ends of the two protrusions 82 provided on the swing follower portion 72 come into contact with the window upper edge surface 58 of the differential case 40, and the differential case 40 is positioned at a specific rotational phase.

[0046] The differential case 40, which has been centered and positioned in phase as described above, is transported by the workpiece transport unit 10. The destination is above a central protrusion 103 provided on a processing jig 102, to a position where the central axis C3 of the workpiece support plate 33 and the centering boss 60 coincides with the central axis C4 of the central protrusion 103 (see FIG. 9). At this time, since the differential case 40 is centered and its center position on the arm 32 is identified, the center of the central protrusion 103 of the processing jig 102 and the center of the differential case 40 can be aligned with high precision.

[0047] Next, when the workpiece transport unit 10 is lowered, as shown in FIG. 9(a), the differential case 40 is placed on a plurality of support stands 104 provided on the processing jig 102, and the second cylindrical interior 53 of the differential case 40 is inserted into the central protrusion 103 of the processing jig 102. At this time, since the differential case 40 is positioned at a specific rotational phase, it is placed on the processing jig 102 at a specific rotational phase. As a result, a phase positioning protrusion 105 provided on the processing jig 102 is inserted into a specific bolt hole 51 out of a plurality of bolt holes 51 provided in the flange portion 50 of the differential case 40, and the differential case 40 is placed on the processing jig 102 at a predetermined rotational phase.

[0048] When the workpiece transport unit 10 is further lowered from there, as shown in FIG. 9(b), the centering boss 60 is removed from the first cylinder interior 46, and the workpiece support seat surface 34 moves away from the inner annular plane 49. Then, the protruding end side of the arm portion 32 is removed from the accommodation space 42 through the window portion 44, completing the insertion operation of the differential case 40 into the machining position. Thereafter, in the machine tool, the workpiece transport unit 10 attached to the spindle portion is replaced, and a predetermined tool unit is attached to the spindle portion. Using this tool unit, necessary machining such as cutting and drilling is performed on the inner wall portion 43a of the accommodation wall portion 43 of the differential case 40, which is placed on the machining jig 102 while being positioned at a specific rotational phase.

[0049] Next, a case where the machined differential case 40 is removed from the machining position using the workpiece transport unit 10 will be described.

[0050] As shown in FIG. 10(a), the machined differential case 40 is placed on a machining jig 102, and machining such as cutting and drilling is performed on the inner wall portion 43a of the gear accommodating portion 41. As a result, chips K remain in the accommodation space 42 of the gear accommodating portion 41 and the second cylindrical interior 53 of the second shaft insertion portion 52. When removing the differential case 40, the tool unit attached to the main shaft is replaced, and the workpiece transport unit 10 is reattached to the main shaft. Then, under the control of the machine tool, coolant is introduced into the inlet 24 provided at the upper end of the holder portion 20 and discharged from the first discharge port 91 and the second discharge port 92. In this case, the coolant is discharged vertically downward from the first discharge port 91 provided on the lower surface of the workpiece support plate portion 33 on the central axis C3. The coolant is discharged diagonally downward outward from the second discharge ports 92 provided at both widthwise ends of the arm portion 32.

[0051] With the coolant being discharged, as shown in FIG. 10(b), the protruding end of the arm 32 is inserted into the accommodation space 42 of the gear accommodating section 41 through the window 44 on the side where the workpiece transport unit 10 is located, with the differential case 40 placed on the machining jig 102. When the protruding end of the arm 32 is inserted into the accommodation space 42, the coolant discharged from the first outlet 91 and the second outlet 92 flows into the accommodation space 42 and the second cylinder interior 53. The coolant is discharged from the first outlet 91 toward the bottom of the accommodation space 42 and from the multiple second outlets 92 toward a wide area below the inner wall 43a. This discharging of coolant in different directions creates a powerful flow of coolant in the accommodation space 42. Chips K accumulated in the accommodation space 42 are caught up in this flow and are discharged together with the coolant out of the gear accommodating section 41 through openings such as the window 44.

[0052] Next, the centering boss 60 is positioned below the first cylinder interior 46, and then the workpiece transport unit 10 is moved upward. During this operation, coolant is still being discharged from the first discharge port 91 and the second discharge port 92, and the discharged coolant is discharged to the outside of the gear accommodating portion 41 through openings such as the window portion 44, while carrying with it chips K remaining in the accommodating space 42.

[0053] In particular, when the centering boss 60 is located below the first-tube interior 46, the first discharge port 91 is located above the second-tube interior 53. Therefore, the coolant discharged downward from the first discharge port 91 enters the second-tube interior 53. The coolant that enters the second-tube interior 53 hits the central protrusion 103 of the machining jig 102 present in the second-tube interior 53, forming a rebound flow. In addition, the coolant is discharged from the multiple second discharge ports 92 toward a wide area below the inner wall 43a. The discharged coolant hits the inner wall 43a, forming a rebound flow. These two flows form a powerful flow, and the coolant is discharged to the outside of the gear accommodating portion 41 through openings such as the window 44, while dragging along chips K accumulated in the accommodation space 42 and the second-tube interior 53.

[0054] As the workpiece transport unit 10 continues to move upward, the second cylindrical portion 62 of the centering boss 60 is inserted into the small-diameter portion 57 of the first cylindrical interior 46, and the first cylindrical portion 61 is inserted into the large-diameter portion 56, just as when the workpiece was inserted. Thereafter, the workpiece support seating surface 34 abuts against the inner annular flat surface 49. If the workpiece transport unit 10 is further moved upward from there, the inner annular flat surface 49 is placed on the workpiece support seating surface 34, and the differential case 40 is lifted by the workpiece transport unit 10, as shown in FIG. 11(a). At this time, centering is performed by the centering boss 60, and the rotational position (phase) is positioned by the phase positioning device 70. During this operation, the coolant continues to be discharged from the first discharge port 91 and the second discharge port 92, and the flow of coolant washes away chips K present in the accommodation space 42.

[0055] When the differential case 40 is lifted by the workpiece transport unit 10, the central protrusion 103 of the machining jig 102 is removed from the second-tube interior 53. The second open port 55 of the second-tube interior 53 is no longer blocked by the central protrusion 103 and opens downward. As a result, the coolant discharged from the first discharge port 91 and the second discharge port 92 is not only discharged through openings such as the window portion 44, but also discharged downward from the second open port 55 through the second-tube interior 53, carrying chips K with it. In addition, the coolant discharged downward from the second open port 55 also washes away chips K adhering to the central protrusion 103 of the machining jig 102 and chips K present on the upper surface of the machining jig 102.

[0056] 11(b), the machined differential case 40 is then transported above a workpiece placement table 106 provided at a predetermined removal position. From there, the workpiece transport unit 10 is lowered to place the differential case 40 on the workpiece placement table 106. At this time, the differential case 40 is centered and its central position on the arm portion 32 is identified. Therefore, the differential case 40 is placed with high precision above an arbitrary placement position on the workpiece placement table 106 (for example, a position required for movement to the next process).

[0057] When the workpiece transport unit 10 is further lowered, the centering boss 60 is removed from the first cylinder interior 46, and the workpiece support seat surface 34 moves away from the inner annular plane 49. Then, the protruding end side of the arm portion 32 is removed from the accommodation space 42 through the window portion 44, completing the operation of discharging the differential case 40 to the discharge position. The coolant continues to be discharged until the machined differential case 40 is placed on the workpiece table 106, or until it is transported to a predetermined position before being placed thereon.

[0058] According to the workpiece transport unit 10 of this embodiment described above, the following effects can be obtained.

[0059] (1) If the work transport unit 10 is attached to the spindle of a machine tool, the work W can be transported using the work transport unit 10 by controlling the drive of the spindle. When transporting a differential case 40 as the work W, the inner annular flat surface 49 of the differential case 40 is placed on the work support seat surface 34, and when the spindle moves upward, the differential case 40 is lifted and supported. If the work transport unit 10 is further moved by the spindle, the differential case 40 can be transported to a desired position. In this case, the differential case 40 is not held by a mechanism using coolant as the working fluid as in the conventional technology, but rather the inner annular flat surface 49 of the differential case 40 is simply placed on the work support seat surface 34. This simplifies the structure, reducing product manufacturing costs and machine tool maintenance costs.

[0060] Furthermore, when transporting the differential case 40 after machining such as cutting and drilling using a machine tool, coolant can be discharged from the coolant discharge portion 90 onto the differential case 40 supported by the work support seat surface 34. This allows chips K that have adhered to or accumulated on the differential case 40 to be washed away, thereby cleaning the differential case 40. If chips K can be removed at the same time as transporting the processed differential case 40, it is possible to eliminate or simplify the chip removal process using a cleaning device, which also further reduces product manufacturing costs.

[0061] (2) The workpiece support seat surface 34 is provided with centering bosses 60, which allow the differential case 40 to be positioned on the arm portion 32 when the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat surface 34. This positioning identifies the center position of the transported differential case 40 on the arm portion 32, so that when the differential case 40 is inserted into the processing position, the center of the processing jig 102 and the center of the differential case 40 can be aligned, allowing the differential case 40 to be accurately positioned on the processing jig 102. Furthermore, when the differential case 40 is delivered to the removal position, the differential case 40 can be accurately positioned at any desired placement position, such as on the workpiece placement table 106.

[0062] (3) The arm portion 32 is provided with a phase positioning device 70, which positions the inner annular flat surface 49 of the differential case 40 at a specific rotational phase among rotational phases about the central axis C2 of the differential case 40 when the inner annular flat surface 49 of the differential case 40 is placed on the work support seat surface 34. As a result, the transported differential case 40 is placed on the processing jig 102 while being positioned at a specific rotational phase, and processing such as cutting and drilling can be performed on the differential case 40.

[0063] In this way, when loading the differential case 40 before machining, it is necessary to place the differential case 40 on the machining jig 102 at a specific rotational phase. Therefore, if the phase positioning device 70 is not provided in this work transport unit 10, the work transport unit 10 can only be used for transporting the work at the time of discharge and, at the same time, for cleaning the chips K. Therefore, when loading a work that requires phase positioning, it is necessary to provide a work loading unit equipped with the phase positioning device 70 separately from the work transport unit 10.

[0064] In this regard, the workpiece transport unit 10 of this embodiment not only has the function of removing chips K by washing with coolant while transporting the workpiece for unloading, but also can be used for transporting the workpiece when loading it because it is provided with a phase positioning device 70. This allows the transport of the workpiece W when loading it, the transport of the workpiece when unloading it, and the washing away of chips K to be performed by a single workpiece transport unit 10, which can contribute to reducing product manufacturing costs.

[0065] (4) The phase positioning device 70 has a pair of protrusions 82 provided on the oscillating portion 71 and the oscillating follower portion 72. When the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat 34, the oscillating portion 71, which is in its base state, is pressed down by the inner annular flat surface 49 due to the biasing force of the coil spring 77. The oscillating portion 71 rotates around the pivot shaft 73 and enters a pressed-down state. When the oscillating portion 71 enters the pressed-down state, the protruding ends of the pair of protrusions 82, which are provided at separate positions, abut against the upper edge surface 58 of the window portion of the differential case 40, and the two protruding ends press the differential case 40 in the arm protrusion direction. This positions the differential case 40 at a specific rotational phase. In this way, phase positioning can be performed using a simple mechanical mechanism in accordance with the placement of the inner annular flat surface 49 of the differential case 40 on the workpiece support seat 34.

[0066] (5) In this embodiment, the workpiece W to be transported by the workpiece transport unit 10 is a differential case 40. The differential case 40 has a gear housing portion 41 having a housing space 42 that houses gears, and a housing wall portion 43 that forms the gear housing portion 41. An inner wall portion 43a of the housing wall portion 43 is subjected to machining, such as cutting and drilling, by a machine tool. As a result, chips K accumulate on the bottom side of the housing space 42. When the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat surface 34, the protruding end side of the arm portion 32 is positioned in the housing space 42. The coolant discharge portion 90 is provided on the protruding end side of the arm portion 32 and discharges coolant toward the inner wall portion 43a of the housing wall portion 43. Therefore, when the discharged coolant is discharged from openings such as the window portion 44, chips K present in the housing space 42 can be washed away.

[0067] (6) When the inner annular flat surface 49 of the differential case 40 is placed on the workpiece support seat surface 34, the protruding end side of the arm portion 32 is positioned on the ceiling side of the accommodation space 42. The coolant discharge portion 90 has a first discharge port 91 and a second discharge port 92. The first discharge port 91 is provided above the second shaft insertion portion 52 and discharges coolant downward. A plurality of second discharge ports 92 are provided at both ends of the arm portion 32 in the width direction and each discharges coolant diagonally downward outward. Discharging the coolant in such different directions creates a powerful flow that entrains the chips K and discharges them from the window portion 44 and the second cylinder interior 53, thereby ensuring the removal of the chips K.

[0068] (7) The differential case 40 serving as the workpiece W has a second shaft insertion portion 52 communicating with the accommodation space 42 at one end on the central axis C2. When the differential case 40 is placed on the machining jig 102, the central protrusion 103 of the machining jig 102 is inserted into the second cylindrical interior 53 of the second shaft insertion portion 52, thereby determining the center position of the differential case 40 on the machining jig 102. When the inner annular flat surface 49 of the workpiece W abuts against the workpiece support seat surface 34 in this state, the first discharge port 91 is positioned above the second communication port 54 in the second cylindrical interior 53 and discharges coolant toward the second communication port 54. Therefore, chips K accumulated in the second cylindrical interior 53 blocked by the central protrusion 103 can be washed away. Furthermore, when the differential case 40 is lifted and the central protrusion 103 is removed from the second cylinder interior 53, the second cylinder interior 53 is opened to the outside through the second open port 55, and the coolant is discharged downward from the second open port 55. This flow of coolant can wash away chips K adhering to the central protrusion 103.

[0069] (8) In the differential case 40, machining such as cutting and drilling is performed on the inner wall portion 43a of the housing wall portion 43, causing chips K to accumulate at the bottom of the housing space 42. In this case, when the inner annular flat surface 49 of the differential case 40 abuts against the workpiece support seat surface 34, the second discharge port 92 discharges coolant toward the underside of the inner wall portion 43a of the housing wall portion 43. The discharged coolant bounces off the inner wall portion 43a, creating a powerful flow of coolant at the bottom side of the housing space 42, which is discharged from the window portion 44 and the second open port 55 of the second cylinder interior 53. This allows chips K accumulated at the bottom of the housing space 42 to be more reliably washed away.

[0070] The embodiment of the present invention is not limited to the workpiece transport unit 10 of the above embodiment, and may be, for example, in the following form.

[0071] (a) The workpiece transport unit 10 of this embodiment employs a configuration in which the arm portion 32 protrudes perpendicularly to the central axis C1 of the holder portion 20 so that it can be used when the central axis of the spindle is vertical, such as in a vertical machining center. For example, the arm portion 32 may protrude in a direction along the central axis C1 of the holder portion 20 so that it can be used when the central axis of the spindle is horizontal, such as in a horizontal machining center.

[0072] (b) The shank portion 21 of the holder portion 20 of the work transport unit 10 in this embodiment is a BT shank, but the type of shank portion 21 is not particularly limited as long as it is capable of automatic tool replacement, and it may be, for example, an HSK shank.

[0073] (c) The workpiece W does not have to be the differential case 40, and any configuration or type is acceptable as long as it has an abutment portion that abuts against and is supported by the workpiece support seat surface 34 and can be placed on the workpiece support seat surface 34. For example, instead of the abutment portion of the workpiece W being provided in the inner space like the inner annular flat surface 49 of the differential case 40, the underside of the workpiece W may be the abutment portion, and the underside may be placed on the workpiece support seat surface 34. Also, a configuration without a cylindrical portion like the first shaft insertion portion 45 or the second shaft insertion portion 52 is also acceptable.

[0074] (d) The workpiece W may not have an inner space such as the accommodation space 42 of the gear accommodation portion 41 of the differential case 40. In this case, in the case of a workpiece W that does not have an inner space, machining such as cutting or drilling is performed on the outer periphery thereof, and therefore chips K adhere to the outside of the workpiece W. For this reason, the coolant discharge portion 90 is configured to discharge coolant toward the outside of the workpiece W.

[0075] (d) The direction in which the coolant is discharged from the coolant discharge portion 90 provided on the arm portion 32 is arbitrary depending on the configuration in which the workpiece W is placed on the workpiece support seat 34, the shape of the workpiece W, and the location where chips K accumulate or adhere when the workpiece W is machined. For example, the optimal discharge direction for removing chips K can be selected, such as discharging the coolant diagonally upward or to the side of the arm portion 32. Furthermore, although the first discharge port 91 and the second discharge port 92 are provided on the protruding end side of the arm portion 32, the locations in which these discharge ports 91, 92 are provided are arbitrary. It is sufficient to discharge the coolant toward the location where chips K to be washed away have accumulated or adhered.

[0076] (e) Only one first discharge port 91 is provided on the underside of the workpiece support plate portion 33, but multiple first discharge ports 91 may be provided. Also, there may be only one second discharge port 92 provided at each end of the arm portion 32 in the width direction. When multiple first discharge ports 91 are provided, the respective discharge directions may be different, and this is also true when multiple second discharge ports 92 are provided. Furthermore, each of the discharge ports 91, 92 may not be a simple opening, but may be like a shower hole that discharges coolant radially.

[0077] (f) The first shaft insertion portion 45 of the differential case 40 as the workpiece W has a large diameter portion 56 and a small diameter portion 57 in the first cylindrical interior 46, and therefore the centering boss 60 has a first cylindrical portion 61 that is inserted into the large diameter portion 56 and a second cylindrical portion 62 that is inserted into the small diameter portion 57. If the cross section of the first shaft insertion portion 45 were the same throughout the central axis direction, the centering boss 60 would only need to be a single columnar portion.

[0078] (g) The coolant flow passage 93 connecting the coolant inlet 24 provided in the holder portion 20 to the first discharge outlet 91 and the second discharge outlet 92 may be configured as an external passage such as a flow pipe rather than an internal passage.

[0079] 1, a reinforcing member 111 may be provided that connects the shaft portion 31 and the arm portion 32 at an angle and reinforces the arm portion 32. This reinforcing member 111 reinforces the arm portion 32 that is cantilevered relative to the shaft portion 31. As a result, even if the workpiece W placed on the workpiece support seat surface 34 is relatively heavy, the load acting on the connection portion between the arm portion 32 and the shaft portion 31 when the workpiece W is lifted is alleviated, reducing the risk of the arm portion 32 being damaged by the weight of the workpiece W. [Explanation of symbols]

[0080] 10...work transport unit, 21...shank portion, 32...arm portion, 34...work support seat surface (work support seat portion), 40...differential case (work), 41...gear accommodating portion (main body portion), 42...accommodating space (inner space), 44...window portion, 43a...inner wall portion, 49...inner annular plane (contact portion), 53...inside of second cylinder (cylindrical space), 54...second communication port (communication port), 60...centering boss (positioning portion for positioning the mounting position), 70...phase positioning device, 71...oscillating portion (pressed-down portion), 82...protrusion (contact portion), 90...coolant discharge portion, 91...first discharge port, 92...second discharge port, 93...coolant flow passage, 102...machining jig, 103...central protrusion.

Claims

1. A workpiece transport unit that includes a shank portion that is attached to a spindle portion of a machine tool and transports a workpiece while attached to the spindle portion, an arm portion provided on the shank portion; a work support seat provided on the arm portion and configured to support the work by contacting a contacted portion of the work and supporting the contacted portion; a coolant discharge portion provided on the arm portion and configured to discharge coolant toward the workpiece supported by the workpiece support seat; a coolant flow passage that allows coolant supplied from the spindle portion side to flow to the coolant discharge portion when the coolant supply port is attached to the spindle portion; A work transport unit equipped with the above.

2. The work transport unit according to claim 1, further comprising a positioning section for positioning the work so that the work is placed at a predetermined position on the arm section when the abutted portion of the work is placed on the work support seat section.

3. 3. The work transport unit according to claim 1, further comprising a phase positioning device that positions the abutted portion of the work at a specific rotational phase among rotational phases around the central axis of the work when the abutted portion of the work is placed on the work support seat.

4. The phase positioning device a pressed-down portion that is pressed down by the workpiece placed on the workpiece support seat; a contact portion that contacts the workpiece when the pressed-down portion is pressed down, thereby positioning the rotation phase of the workpiece; The workpiece transport unit according to claim 3, further comprising:

5. the workpiece to be transported comprises a main body having an inner space and a window provided in the main body and penetrating the inner space to the outside, and an inner wall portion forming the inner space in the main body is machined by the machine tool; 5. The work transport unit according to claim 4, wherein the coolant discharge portion is provided in a portion that is disposed in the inner space when the abutted portion of the workpiece abuts against the work support seat portion, and discharges coolant toward the inner wall portion.

6. The contacted portion of the workpiece is provided on the ceiling side of the internal space, The workpiece transport unit according to claim 5 , wherein the coolant discharge portion has at least a first discharge port and a second discharge port that discharge the coolant in different directions.

7. The workpiece has a cylindrical space in its main body, one end of which communicates with the inner space and the other end of which is open to the outside, and during machining, the cylindrical space is inserted into a central protrusion provided on a machining jig, thereby positioning the center of the workpiece on the machining jig; 7. The work transport unit according to claim 6, wherein when the abutted portion of the workpiece abuts against the workpiece support seat portion while the center position on the machining jig is positioned, the first discharge port is positioned above a communication port through which the cylindrical space opens toward the inner space, and discharges coolant toward the communication port.

8. The workpiece transport unit according to claim 6 , wherein the second discharge port discharges the coolant toward a lower side of the inner wall portion when the contacted portion of the workpiece contacts the workpiece support seat portion.

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