JP4611833B2 - Internal processing method and internal processing apparatus for differential case - Google Patents

Description

  The present invention relates to an inner surface processing method and an inner surface processing apparatus for processing an inner surface of a differential case (so-called differential case) which is a constituent element of a differential device.

  For example, as a device constituting a driving force transmission system of an automobile, a differential device for realizing smooth rolling traveling by absorbing a difference in rotational speed between left and right driving wheels or front and rear driving axles is known. The differential case, which is the main body of the differential device, is configured as a hollow case body having a gear housing chamber defined therein, and a plurality of types of gears are incorporated in the gear housing chamber in a complicated manner. For this reason, various inner surface processing is given before a differential case is completed. More specifically, a pair of upper and lower spherical seats for rotatably supporting a pair of upper and lower bevel gear-shaped pinion gears, a pair of left and right plane seats for rotatably supporting a pair of left and right bevel gear-shaped side gears, and an axle Various inner surfaces such as an inner peripheral surface of a cylindrical portion (cylindrical support portion) opened to the left and right of the differential case are processed and formed inside the differential case.

  In general, when machining the inner and outer surfaces of the differential case, a plurality of types of lathes and machining centers are used for each process. For example, even when limited to inner surface machining, a lathe A is used to machine the inner circumferential surface of the cylindrical portion on the left side of the differential case, and a lathe B is used to machine the inner circumferential surface of the cylindrical portion on the right side of the differential case. The machining center C is used to process the left and right planar seats in the differential case, and the machining center D is used to process the upper and lower spherical seats in the differential case. As described above, work (chucking) is frequently performed in which a differential case, which is a workpiece, is replaced with a new lathe or machining center for each process, so that the work efficiency through all processes is not high. Further, as the number of times of chucking increases, a decrease in the relative position accuracy between the processing surfaces is promoted. The present invention has been made in view of such circumstances.

  In the prior art search by the present applicant, Patent Documents 1, 2 and 3 are given as prior art documents relating to the processing method of the pinion gear spherical seat in the differential case, and the side gear plane seat in the differential case. Patent Document 4 has been found as prior art documents relating to this processing method. However, all of the techniques of Patent Documents 1 to 3 are clearly different from the present invention in that they are aimed at accurate processing and forming of the spherical seat. Moreover, all of the techniques of Patent Documents 1 to 4 are clearly different from the present invention in that inner surface machining is performed by fixedly gripping a differential case that is a workpiece and rotationally driving cutting tools.

JP-A-2004-90181 (Differential case manufacturing method for differential) JP 2005-125473 A (Differential Case Processing Method) JP-A-2005-34974 (inner surface machining method for hollow workpiece) JP-A-2005-7534 (work processing machine and work processing method)

  An object of the present invention is to provide a differential case inner surface processing method capable of accurately processing the inner surfaces of a plurality of locations in a differential case while the differential case as a workpiece is held by a chuck mechanism. There is. Moreover, it is providing the inner surface processing apparatus of the differential case suitable for implementation of the method.

  The invention according to claim 1 is a method of applying inner surface processing to a differential case having a gear storage chamber and two cylindrical portions located on both sides thereof and extending along the center line (C) of the case. After the differential case is gripped by using a chuck mechanism that can rotate integrally with the differential case with the center line (C) of the differential case as the rotation axis, the differential case is rotated when the chuck mechanism and the differential case are rotated. A flat cutter clamped and supported in the gear housing chamber by a first shaft inserted into one cylindrical portion of the first shaft and a second shaft inserted into the other cylindrical portion of the differential case. Planar seat processing for cutting the gear plane seat on the inner wall, and inner peripheral surface for cutting the inner peripheral surface of the differential case cylindrical portion with a long tool inserted from either cylindrical portion of the differential case Processing, said A inner surface machining method of the differential case which is characterized by removing the differential case from the chuck mechanism after completion of the surface locus machining and the inner peripheral surface machining.

  The invention according to claim 2 is a method of applying inner surface processing to a differential case having a gear storage chamber and two cylindrical portions located on both sides thereof and extending along the center line (C) of the case. A chucking process for gripping one cylindrical portion of the differential case or the vicinity thereof using a chuck mechanism that can rotate integrally with the differential case using the center line (C) of the differential case as a rotation axis, and the chuck mechanism Under the gripping state of the differential case, a plane cutter is carried into the gear housing chamber of the differential case, and the first shaft provided in the central region of the chuck mechanism is inserted into one cylindrical portion of the differential case and A second shaft facing the first shaft is inserted into the other cylindrical portion of the differential case, and a plane cutter is sandwiched and supported by the first and second shafts, and the center line (C) is the rotation axis. Cha By rotating the three members of the first shaft, the flat cutter, and the second shaft synchronously reciprocating along the center line (C) of the differential case when the clamp mechanism and the differential case rotate. A flat seat processing step for spotting a pair of gear plane seats facing the inner wall of the gear storage chamber, and a gripping state of the differential case by the chuck mechanism, provided in the central region of the chuck mechanism The first shaft is inserted from one cylindrical portion of the differential case, and the distal end portion of the first shaft is brought into contact with the distal end portion of a long tool as a shaft-shaped tool facing the first shaft, and the center line (C ) Is rotated along the center line (C) of the differential case while the chuck mechanism and the differential case are rotated while maintaining the contact state between them. An inner peripheral surface machining step of cutting the inner peripheral surface of each cylindrical portion of the differential case, and a step of removing the differential case from the chuck mechanism after the flat seat machining step and the inner peripheral surface machining step are completed. This is a method for processing the inner surface of the differential case.

The invention of claim 3 is an inner surface processing apparatus for a differential case comprising a workpiece gripping rotation and shaft drive mechanism, a tool feed mechanism disposed opposite thereto, and a flat cutter transport mechanism ,
The workpiece gripping rotation and shaft drive mechanism includes a chuck mechanism that can grip a differential case as a workpiece and that can rotate integrally with the differential case with the center line (C) of the differential case as a rotation axis (L), A workpiece driving means for forcibly rotating the chuck mechanism and the differential case held by the chuck mechanism, a center shaft movably provided along the rotation axis (L) at the center of the chuck mechanism, and the center shaft Shaft drive means for moving, and
The tool feeding mechanism includes a planar cutter holding shaft and / or a long tool as a shaft-like tool that can be disposed opposite to the center shaft of the workpiece gripping rotation and shaft driving mechanism, and the shaft-like tool is attached to the differential case. The chuck mechanism is configured to be movable back and forth along the rotation axis (L) of the chuck mechanism so as to approach and separate .
The flat cutter conveyance mechanism can hold a flat cutter for spotting a gear flat seat on the inner wall portion of the gear storage chamber of a differential case as a workpiece, and the differential gripped by the chuck mechanism An apparatus for processing an inner surface of a differential case , wherein a flat cutter is carried into a gear housing chamber of the case and a flat cutter is carried out from the gear housing chamber .

The invention of claim 4 is a differential case inner surface machining apparatus comprising at least a workpiece gripping rotation and shaft drive mechanism (20) and a tool feed mechanism (100) disposed opposite thereto.
The workpiece gripping rotation and shaft drive mechanism (20) is a chuck mechanism that can grip a differential case as a workpiece and can rotate integrally with the differential case with the center line (C) of the differential case as a rotation axis (L). (30), a workpiece driving means for forcibly rotating the chuck mechanism and the differential case gripped by the chuck mechanism, and a center shaft provided movably along the rotation axis (L) at the center of the chuck mechanism (42) and a shaft drive means (22) for moving the center shaft,
The tool feed mechanism (100) includes a turret head equipped with a flat cutter holding shaft (101) and a long bite (102) as a shaft-like tool that can be disposed opposite to the center shaft of the workpiece gripping rotation and shaft drive mechanism. In addition, the shaft-shaped tool is configured to be movable back and forth along the rotation axis (L) of the chuck mechanism so as to approach and separate the differential tool from the differential case.
When the flat cutter holding shaft (101) of the shaft-like tools equipped on the turret head is selected, in the gear housing chamber of the differential case, the center shaft (42) and the flat cutter holding shaft ( 101) and in a state of sandwiching and supporting the flat cutter (202), the three of the center shaft (42), flat cutter (202) and flat cutter holding shaft (101) are synchronously reciprocated, A pair of gear plane seats facing each other on the inner wall of the gear housing chamber of the differential case are countersunk,
When the long tool (102) is selected from the shaft-like tools mounted on the turret head, the center penetrating the two cylindrical portions of the differential case and the gear storage chamber outside the differential case. The tip of the shaft (42) is brought into contact with the tip of the long bite (102), and both of them are moved synchronously along the center line (C) of the differential case while maintaining the contact state between the two. By cutting the inner peripheral surface of each cylindrical portion of the differential case,
This is an inner surface processing apparatus for a differential case.
The center shaft cooperates with the flat cutter holding shaft to hold the flat cutter in the gear housing chamber of the differential case, and comes into contact with the tip of the long cutting tool when cutting the long cutting tool. It works to stabilize the posture.

According to a fifth aspect of the present invention, in the differential case inner surface processing apparatus according to the fourth aspect, a flat cutter for spotting a gear plane seat on the inner wall portion of the gear housing chamber of the differential case as a workpiece ( 202) and a plane cutter transport mechanism (200) for carrying the plane cutter into and out of the gear storage chamber of the differential case gripped by the chuck mechanism. It is characterized by comprising.

  According to the method for processing the inner surface of the differential case according to claim 1 and 2, the differential case is gripped and rotated using a chuck mechanism that can rotate integrally with the differential case with the center line (C) of the differential case as a rotation axis. Inside, the flat seat processing is performed with a flat cutter supported tightly by the first and second shafts inserted into each cylindrical part of the differential case, and the cylindrical part with a long tool inserted into the cylindrical part of the differential case The procedure or process of removing the differential case from the chuck mechanism was then adopted. For this reason, it is possible to process the inner surfaces (planar seat and inner peripheral surface of the cylindrical portion) at a plurality of locations in the differential case while maintaining a single gripping state (one chuck state) by the chuck mechanism. The working efficiency of the inner surface processing can be increased as compared with the conventional one. In addition, since the number of chucking operations for the inner surface processing of the differential case can be reduced as compared with the conventional case, it is possible to increase the accuracy of the inner surface processing by suppressing a decrease in the relative position accuracy between the processing surfaces.

  In particular, according to the second aspect, the differential case gripped by the chuck mechanism is integrally rotated together with the chuck mechanism, while the first shaft provided in the central region of the chuck mechanism and the second shaft opposed thereto are planar. The cutter was supported tightly, and the first shaft, the flat cutter, and the second shaft were synchronously reciprocated along the center line (C) of the differential case during flat seat processing. That is, the relative rotation between the differential case, which is a workpiece, and the flat cutter, which is a cutting tool, which is necessary for flat seat processing, is shared by the chuck mechanism that holds the differential case, while the flat cutter The first and second shafts that tightly support the blades share a cutting feed function for linearly reciprocating the flat cutter. Therefore, the rotation driving mechanism of the chuck mechanism and the driving mechanism of the first and second shafts can be made different from each other, and the respective mechanical structures can be simplified.

  Further, according to claim 2, in the inner peripheral surface machining step, while maintaining the contact state between the first shaft inserted into one cylindrical portion of the differential case and the long tool as the shaft-like tool, Are synchronously moved along the center line (C) of the differential case to cut the inner peripheral surface of each cylindrical portion of the differential case. In other words, the long bite comes into contact with the first shaft and is integrated with the first shaft, so that the cutting force can be received in that state. For this reason, the posture of the long bite during the machining of the inner peripheral surface of the cylindrical portion is stabilized, vibration of the long bite and position blurring are avoided as much as possible, and the cutting accuracy of the inner peripheral surface of the cylindrical portion is increased. In addition, since the inner peripheral surface processing of the two cylindrical portions can be completed in the same process by the long tool integrated with the first shaft, the coaxiality of both the cylindrical portions can be reliably ensured.

  According to the differential case inner surface machining apparatus of the third to fifth aspects, the method for machining the inner surface of the differential case can be carried out smoothly and reliably. That is, the inner surface (plane seat and inner peripheral surface of the cylindrical portion) in a plurality of locations in the differential case can be accurately processed with excellent processing accuracy while the differential case as a workpiece is held by the chuck mechanism. . In particular, in this inner surface processing apparatus, a chuck mechanism and a workpiece driving means constituting a workpiece gripping rotation and shaft driving mechanism share the function of gripping and rotating the differential case, a center shaft constituting the workpiece gripping rotation and shaft driving mechanism, and A shaft feed means and a tool feed mechanism provided with a shaft-shaped tool facing the center shaft share the function of linearly cutting and feeding a flat cutter and / or a long tool. In this way, the part responsible for the gripping rotation function of the differential case and the part responsible for the cutting feed of the tool are mechanically separated, so avoid the complication of the mechanical structure of the part responsible for each function, and compare It is possible to make a simple configuration.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a differential case 10 which is an object (workpiece) for inner surface machining, and FIGS. 2 to 6 show an outline of the structure and operation of the inner surface machining apparatus used in this embodiment.

[Differential case inner surface processing equipment]
As shown in FIGS. 3 to 6, the differential case inner surface machining apparatus includes a workpiece gripping rotation and shaft drive mechanism 20, a first saddle 100 as a tool feed mechanism, and a second as a planar cutter transport mechanism. It consists of a saddle 200.

  The workpiece gripping rotation and shaft drive mechanism 20 grips the differential case 10 as a workpiece, and a chuck mechanism 30 for forcibly rotating the differential case 10 with the center line C of the differential case 10 as the rotation axis L; This is a special apparatus provided with a center shaft 42 as a first shaft that is provided in the central region of the chuck mechanism 30 and is movable along the rotation axis L of the chuck mechanism 30 (that is, the center line C). Details of the workpiece gripping rotation and shaft drive mechanism 20 will be described later with reference to FIG.

  The first saddle 100 is a tool feed mechanism that is disposed to face the workpiece gripping rotation and shaft drive mechanism 20. The first saddle 100 includes a turret head (not shown) similar to a turret lathe, and the turret head is equipped with a plurality of types of tools. The turret head of the first saddle 100 includes at least two types of shaft-like tools including a flat cutter holding shaft 101 (see FIG. 3) and a long bite 102 (see FIG. 5) as a second shaft, and a normal type Bite and other general tools (not shown) are equipped. When a shaft-like tool (planar cutter holding shaft 101 or long bite 102) is selected from the tools mounted on the turret head, the selected shaft-like tool is the workpiece gripping rotation and center shaft 42 of the shaft drive mechanism 20. It arrange | positions in the position facing. At the time of operation of the inner surface machining apparatus, at least the first saddle 100 functions as a tool feeding mechanism that moves the selected shaft-shaped tool 101 or 102 closer to or away from the differential case 10 held by the chuck mechanism 30.

  As shown in FIGS. 5 and 6, the long cutting tool 102 includes a shaft-shaped cutting tool holder 103 and an internal turning cutting blade 104 mounted near the tip of the tool holder 103. The tip of the bite holder 103 has a flat end surface.

  The second saddle 200 is disposed on the side (downward in FIG. 3) of the differential case 10 gripped by the chucking mechanism 30 of the workpiece gripping rotation and shaft driving mechanism 20 and grips the flat cutter 202. The planar cutter 202 held by the arm 201 is carried into the differential case 10 or functions as a planar cutter transport mechanism for carrying out from the differential case 10. The flat cutter 202 has cutting blades on both the left and right sides, and the left and right sides respectively function as front milling cutters.

  The workpiece gripping rotation and shaft drive mechanism 20, the first saddle 100, and the second saddle 200 are electrically connected to a control device (not shown), and numerical values are based on a control program incorporated in the control device in advance. Be controlled. That is, the inner surface machining apparatus of this embodiment is a kind of NC lathe specialized for machining the inner surface of the differential case 10.

[Work gripping rotation and shaft drive mechanism 20]
As shown in FIG. 2, the workpiece gripping rotation and shaft drive mechanism 20 includes a spindle case 21 provided at the center thereof, and a three-claw as a chuck mechanism provided in front of the spindle case 21 (right side in FIG. 2). The chuck 30 and at least a first drive cylinder 22 and a second drive cylinder 23 provided behind the spindle case 21 (left side in FIG. 2) are provided.

  A spindle 24, a face plate 25, and a three-claw chuck 30 are supported at the front end of the spindle case 21 so as to be integrally rotatable. In the center region of the spindle case 21, a long cylindrical draw bar 26 is provided so as to penetrate the spindle case 21 horizontally and to be rotatable and slidable in the front-rear direction. The rear end portion of the draw bar 26 is operatively connected to the second drive cylinder 23 via an adapter 27, and the front end portion of the draw bar 26 is operatively connected to a three-jaw chuck 30 via a joint 28.

  The three-jaw chuck 30 includes three parent claws 31 (only one is shown) so as to surround the rotation axis L at equal angular intervals, and a child claw 32 is attached to each parent claw 31. The three pairs of parent claws 31 and child claws 32 included in the three-jaw chuck 30 are in operative connection with the draw bar 26 via the internal mechanism of the three-jaw chuck 30 and the joint 28. Therefore, based on the back and forth sliding of the draw bar 26 by the action of the second drive cylinder 23, the three sets of the parent pawl 31 and the child pawl 32 are opened and closed synchronously. To be released.

  Further, the three-jaw chuck 30 is provided with a reference metal 33 and three swing-type clamp arms 34 (only one is shown) so as to face the three sets of the parent pawl 31 and the child pawl 32. ing. Each clamp arm 34 can be switched between a standby position where it does not interfere with the workpiece when the workpiece is attached and detached, and a clamp position (position shown in FIG. 2). The clamp arm 34 disposed at the clamp position presses a part of the workpiece against the reference metal 33 with the clamp claw 35 at the tip thereof, thereby positioning the workpiece in the thrust direction and preventing the workpiece from floating during cutting.

  The second drive cylinder 23 connected to the draw bar 26 is held non-rotatable by a detent 29. On the other hand, the draw bar 26, the spindle 24, the face plate 25, and the three-jaw chuck 30 are operatively connected to a built-in motor (not shown) as a work driving means, and are forcibly rotated integrally by the built-in motor.

  Inside the draw bar 26, a center shaft 42 and an adapter shaft 43 are supported so as to be slidable in the front-rear direction (direction along the rotation axis L) via a slightly long cylindrical shaft bush 41. The center shaft 42 and the adapter shaft 43 are connected in series in the front-rear direction, and practically constitute one shaft connection body. The rear end portion of the adapter shaft 43 is connected to a first drive cylinder 22 as a shaft drive means through a knuckle 44, and the shaft connection body (42, 43) is moved in the front-rear direction by the action of the first drive cylinder 22. Forced slide. The front end of the shaft bush 41 is supported by a bearing 46 in a bearing case 45 provided in the center area of the three-jaw chuck 30. For this reason, even when the draw bar 26, the spindle 24, the face plate 25, and the three-claw chuck 30 are integrally rotated by the built-in motor, the shaft bush 41 does not follow and follows the center shaft 42 and the adapter shaft 43. Is not affected by the rotation of the draw bar 26 or the like.

  When the differential case 10 as a workpiece is gripped by the three-jaw chuck 30, the center line C of the differential case, the rotation axis L of the three-jaw chuck 30, and the center axis of the center shaft 42 are all the same. To do.

[Overview of the whole process of inner and outer surface machining for differential cases]
As shown in FIG. 1, the differential case 10 is configured as a case body that defines a gear storage chamber 11 for incorporating a plurality of pinion gears and side gears therein. The differential case 10 has a left cylindrical portion 12 and a right cylindrical portion 13 located on both sides of the gear storage chamber 11. These two cylindrical portions 12 and 13 provide a tunnel portion for passing the axle shaft of the vehicle, and extend along the center line C of the differential case 10. A flange portion 14 is provided on the outer peripheral portion of the differential case 10 so as to surround the center line C. The flange portion 14 is an attachment portion for fixing a bevel tooth ring gear for transmitting the driving force of the engine to the differential case 10 using a fastener such as a bolt. A mounting hole (not shown) is set. Furthermore, on the left and right inner walls of the gear storage chamber 11, a plane seat (planar seat surface) 15 for seating the flat rear surface of each side gear is set, and on the upper and lower inner walls of the gear storage chamber 11. A spherical seat (spherical seating surface) 16 for seating the spherical rear surface of each pinion gear is set. A pair of upper and lower pinion holes 17 for inserting a pinion gear shaft for coaxially mounting two pinion gears is set in the upper and lower inner walls of the gear storage chamber 11. The differential case 10 is provided with relatively large side openings on both sides (that is, the front side and the back side of the drawing) along the direction orthogonal to the drawing sheet of FIG. Thus, the flat cutter 202 can be carried into or out of the gear storage chamber 11.

  And, for the differential case 10 as an intermediate product obtained by casting, for example, the final product is obtained by performing various processing on the inner surface and outer surface of the case, which consists of four processing stages as described below. The differential case 10 is completed. That is, in the first machining stage, the differential case 10 is mounted on a horizontal NC lathe, and the NC lathe is used for roughing the inner peripheral portion and the outer peripheral portion of the left cylindrical portion 12 and turning the end surface of the flange portion 14. Do. In the second machining stage, the differential case 10 removed from the horizontal NC lathe is mounted on the inner surface machining apparatus of the present embodiment, the machining of the side gear plane seat 15 with respect to the inner wall portion of the gear storage chamber 11, and both the left and right cylindrical portions. 12 and 13 inner peripheral surfaces are finished. A series of processing procedures in the second processing stage will be described in detail later. In the third machining stage, the differential case 10 removed from the inner surface machining apparatus of the present embodiment is mounted on another horizontal NC lathe different from the NC lathe used in the first machining stage, and the NC lathe is used to form a cylinder. Finishing of the outer surface of the part (12, 13) and other parts and drilling of a mounting hole (not shown in FIG. 1) to the flange part 14 are performed. In the fourth machining stage, the differential case 10 removed from the NC lathe used in the third machining stage is mounted on a horizontal machining center, and the machining center finishes the spherical seat 16 for pinion gears and finishes the inner diameter of the pinion hole 17. Processing. Thus, the differential case 10 as the final product is obtained through the first to fourth processing steps.

[Inner surface machining method using inner surface machining apparatus of this embodiment]
A series of inner surface processing procedures using the inner surface processing apparatus of the present embodiment in the second processing stage will be described in more detail with reference to FIGS.

  First, as shown in FIG. 3, the left cylindrical portion 12 of the differential case 10 is gripped by the workpiece gripping rotation and the three-claw chuck 30 of the shaft drive mechanism 20. That is, in the state where the left cylindrical portion 12 of the differential case 10 is disposed in the central area of the three-claw chuck 30, the second drive cylinder 23 closes the three sets of the parent claw 31 and the child claw 32 toward each other. Let Then, the left cylindrical portion 12 of the differential case 10 is gripped by the three-claw chuck 30 in a state where the center line C of the differential case 10 coincides with the rotation axis L of the three-claw chuck 30. Further, the clamp arm 34 is switched to the clamp position in a state where the flange portion 14 of the differential case 10 is in contact with the reference metal 33 (see FIG. 2), and the flange portion 14 is connected to the reference metal 33 with the clamp claws 35 of the clamp arm 34. The thrust positioning of the differential case 10 is performed by pressing against the.

  Next, after adjusting the position (rotation phase) of the three-jaw chuck 30 and the differential case 10 so that one of the two side openings of the differential case 10 faces the second saddle 200, 3 is slid from the standby position of FIG. 3 toward the differential case 10, and the flat cutter 202 held by the arm 201 is carried into the gear storage chamber 11 of the differential case 10. Subsequently, the first drive cylinder 22 is operated to insert the center shaft 42 into the left cylindrical portion 12 of the differential case 10. Further, the first saddle 100 in which the flat cutter holding shaft 101 is selected as a tool is slid in the direction approaching the three-jaw chuck 30 from the standby position in FIG. 3, and the holding shaft 101 is moved to the right cylinder of the differential case 10. Insert into part 13. Then, as shown in FIG. 4, the flat cutter 202 is closely attached from the left and right sides of the center shaft 42 on the three-jaw chuck 30 side and the holding shaft 101 on the first saddle 100 side. Thus, the flat cutter 202 is tightly supported by the two shafts 42 and 101 while the central axis of the flat cutter 202 is aligned with the rotation axis L of the three-jaw chuck 30, and the flat cutter 202 is held in the gear storage chamber 11. Leave it floating.

  In this state, the three-jaw chuck 30 and the differential case 10 are forcibly rotated by the built-in motor. During this forced rotation, the center shaft 42 and the flat cutter holding shaft 101 are synchronously slid in the same direction and at the same speed. That is, by numerically controlling the sliding direction, sliding speed, and sliding amount (displacement amount) of the shafts 42 and 101, the center shaft 42, the flat cutter 202, and the flat cutter holding shaft 101 are centered on the differential case 10. Slide (i.e., reciprocate) synchronously along line C to the left and right. In this way, the left and right inner walls of the gear housing chamber 11 of the differential case 10 are subjected to counterbore processing (milling) by the flat cutter 202, and as a result, a pair of gears facing each other in the gear housing chamber 11. A flat seat 15 is formed.

  When the processing of the pair of gear plane seats 15 is completed, the plane cutter 202 is returned to an intermediate position between the two plane seats 15 and the rotation of the three-jaw chuck 30 and the differential case 10 is also temporarily stopped. Thereafter, the flat cutter 202 is gripped by the arm 201 of the second saddle 200 and returned to the standby position of FIG. 3 together with the second saddle 200. Further, the center shaft 42 and the flat cutter holding shaft 101 are returned to the standby position shown in FIG.

  Subsequently, the inner peripheral surfaces of both cylindrical portions 12 and 13 are finished while maintaining the gripping state of the differential case 10 by the three-jaw chuck 30. In that case, first, a long bite 102 which is one of the shaft-like tools is selected from the tools mounted on the turret head on the first saddle 100 side, and the long bite 102 is selected with respect to the center shaft 42. It is made to oppose (refer FIG. 5). Then, as shown in FIG. 5, after the center shaft 42 is advanced to the right until the center shaft 42 penetrates the left cylindrical portion 12, the gear storage chamber 11, and the right cylindrical portion 13 of the differential case 10, the center shaft 42 The tip of 42 is brought into contact with the tip of the long bite 102.

  In this state, the three-jaw chuck 30 and the differential case 10 are forcibly rotated by the built-in motor. During this forced rotation, the center shaft 42 and the long bite 102 are synchronously slid in the left direction (direction approaching the three-jaw chuck 30) at the same speed. That is, by numerically controlling the sliding direction, sliding speed, and sliding amount (displacement amount) of the center shaft 42 and the long bite 102, the center shaft 42 and the long bite 102 are maintained in the abutting state while being integrated. It is slid to the left synchronously along the center line C of the moving case (see FIG. 6). In this way, the long bite 102 is caused to enter the differential case 10 from the right cylindrical portion 13 and reach the left end of the left cylindrical portion 12, so that the inner peripheral portion of each cylindrical portion 12, 13 of the differential case is Turning with the cutting blade 104 of the long bite 102 is performed, and the inner peripheral surfaces of both cylindrical portions 12 and 13 are finished.

  When finishing of the inner peripheral surfaces of both cylindrical portions 12 and 13 is completed, the rotation of the differential case 10 and the like is stopped, and the long cutting tool 102 is kept so that the cutting blade 104 does not contact the inner peripheral surfaces of both cylindrical portions 12 and 13. Is returned to the standby position (see FIG. 5), and the second processing stage is completed. In addition, the differential arm 10 is removed from the three-jaw chuck 30 by switching the clamp arm 34 from the clamp position to the standby position and opening the three sets of the parent claws 31 and the child claws 32 in a direction away from each other. It is.

[Effect of the embodiment]
According to the present embodiment, in a single gripping state (one chuck state) by the three-jaw chuck mechanism 30, the counterbore processing of the pair of flat seats 15 in the differential case gear storage chamber 11, and both the left and right cylindrical portions Since the inner peripheral surface processing of 12, 13 can be performed, the work efficiency of the inner surface processing of the differential case 10 can be increased as compared with the conventional case. Moreover, since the number of times of chucking for processing the inner surface of the differential case 10 can be reduced as compared with the conventional case, it is possible to suppress a decrease in relative position accuracy between the processing surfaces.

  In the inner surface processing apparatus of the present embodiment, the three-jaw chuck 30 constituting the workpiece gripping rotation and shaft driving mechanism 20 and the built-in motor as the workpiece driving means share the function of gripping and rotating the differential case 10. . On the other hand, a center shaft 42 constituting the workpiece gripping rotation and shaft drive mechanism 20, a first drive cylinder 22 as a shaft drive means, and a shaft-like tool (101 or 102) that can face the center shaft 42 are provided. The first saddle 100 as a tool feeding mechanism shares the function of cutting and feeding the flat cutter 202 and the long bite 102 linearly. That is, the part responsible for the gripping rotation function of the differential case 10 and the part responsible for the tool cutting feed function are mechanically separated. For this reason, it is possible to make each part relatively simple without complicating the mechanical structure of the part responsible for each function, and it is possible to reduce the equipment cost.

  In the inner peripheral surface machining step of the cylindrical portions 12 and 13 shown in FIGS. 5 and 6, the long bite 102 that is cantilevered on the first saddle 100 side receives the abutment of the center shaft 42 and is integrated therewith. That is, it will be in a state of supporting both ends. Therefore, the posture of the long bite 102 at the time of cutting the inner peripheral surface is stabilized, and vibration and position blur of the long bite 102 are avoided as much as possible, and the cutting accuracy of the inner peripheral surface of the cylindrical portion is increased. Further, since the inner peripheral surface machining of the left and right cylindrical portions 12 and 13 is completed at a time by moving the long tool 102 integrated with the center shaft 42 in one direction, the coaxiality of both the cylindrical portions 12 and 13 is ensured. Can be secured.

  [Modification] In the above embodiment, one cylindrical portion 12 of the differential case 10 is gripped by the three-claw chuck 30, but instead, the three-claw chuck is provided around the flange portion 14 of the differential case 10. You may make it hold | grip with 30.

  [Modification] In the second processing stage in the above embodiment, the processing of the flat seat 15 by the flat cutter 202 and the inner peripheral surface processing of the cylindrical portions 12 and 13 by the long bite 102 are performed. While maintaining the gripping state of the differential case 10 by the three-jaw chuck 30, a normal tool is selected from the tools mounted on the turret head on the first saddle 100 side. Rough turning may be applied to the outer peripheral portion of the right cylindrical portion 13.

Sectional drawing of the differential case as a workpiece | work. The schematic sectional drawing of the workpiece | work holding | grip rotation and shaft drive mechanism of an internal surface processing apparatus. The figure which shows before the start of the plane seat process by a plane cutter. The figure which shows the time of the plane seat process by a plane cutter. The figure which shows before the start of a cylindrical part internal peripheral surface process by a long bite. The figure which shows the time of cylindrical part internal peripheral surface processing by a long tool.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Differential case (workpiece), 11 ... Gear storage chamber, 12 ... Left cylindrical part, 13 ... Right cylindrical part, 14 ... Flange part, 15 ... Planar seat, 16 ... Spherical seat, 20 ... Work gripping rotation and Shaft drive mechanism, 22 ... first drive cylinder (shaft drive means), 23 ... second drive cylinder, 30 ... three-claw chuck (chuck mechanism), 42 ... center shaft (first shaft), 43 ... adapter shaft, DESCRIPTION OF SYMBOLS 100 ... 1st saddle (tool feed mechanism), 101 ... Flat cutter holding shaft (2nd shaft), 102 ... Long bite, 200 ... 2nd saddle (plane cutter conveyance mechanism), 202 ... Flat cutter, C ... Center line of the differential case, L ... rotation axis.

Claims (5)

A method of applying inner surface processing to a differential case having a gear storage chamber and two cylindrical portions located on both sides thereof and extending along the center line (C) of the case,
After gripping the differential case using a chuck mechanism that can rotate integrally with the differential case with the center line (C) of the differential case as the rotation axis,
During rotation of the chuck mechanism and the differential case, the first shaft inserted into one cylindrical portion of the differential case and the second shaft inserted into the other cylindrical portion of the differential case are clamped in the gear housing chamber. Flat seat processing for cutting the gear plane seat on the inner wall of the gear housing chamber of the differential case with a supported flat cutter, and the differential case with a long bit inserted from one cylindrical portion of the differential case The inner peripheral surface machining that cuts the inner peripheral surface of the cylindrical part of
A method for processing an inner surface of a differential case, comprising: removing the differential case from the chuck mechanism after completion of the flat seat processing and inner peripheral surface processing. A method of applying inner surface processing to a differential case having a gear storage chamber and two cylindrical portions located on both sides thereof and extending along the center line (C) of the case,
A chucking step of gripping one cylindrical portion of the differential case or the vicinity thereof using a chuck mechanism that can rotate integrally with the differential case with the center line (C) of the differential case as the rotation axis.
Under the gripping state of the differential case by the chuck mechanism, a plane cutter is carried into the gear housing chamber of the differential case, and the first shaft provided in the central region of the chuck mechanism is attached to one cylindrical portion of the differential case. A second shaft that is inserted and is opposed to the first shaft is inserted into the other cylindrical portion of the differential case, and a plane cutter is sandwiched and supported by the first and second shafts, and the center line (C When the chuck mechanism and the differential case are rotated about the rotation axis, the first shaft, the flat cutter and the second shaft are synchronously reciprocated along the center line (C) of the differential case. By doing this, a plane seat machining step for spot facing a pair of gear plane seats opposed to the inner wall portion of the gear storage chamber of the differential case,
Under the gripping state of the differential case by the chuck mechanism, the first shaft provided in the central region of the chuck mechanism is inserted from one cylindrical portion of the differential case, and the tip of the first shaft is inserted into the first shaft. The first shaft and the long tool are brought into contact with each other at the time of rotation of the chuck mechanism and the differential case with the center line (C) as the rotation axis, which is brought into contact with the tip of the long tool as an opposing shaft-shaped tool. An inner peripheral surface machining step of cutting the inner peripheral surface of each cylindrical portion of the differential case by synchronously moving along the center line (C) of the differential case while maintaining the state;
And a step of removing the differential case from the chuck mechanism after completion of the flat seat processing step and the inner peripheral surface processing step. A differential case inner surface processing apparatus comprising a workpiece gripping rotation and shaft drive mechanism, a tool feed mechanism disposed opposite thereto, and a plane cutter transport mechanism ,
The workpiece gripping rotation and shaft drive mechanism includes a chuck mechanism that can grip a differential case as a workpiece and that can rotate integrally with the differential case with the center line (C) of the differential case as a rotation axis (L), A workpiece driving means for forcibly rotating the chuck mechanism and the differential case held by the chuck mechanism, a center shaft movably provided along the rotation axis (L) at the center of the chuck mechanism, and the center shaft Shaft drive means for moving, and
The tool feeding mechanism includes a planar cutter holding shaft and / or a long tool as a shaft-like tool that can be disposed opposite to the center shaft of the workpiece gripping rotation and shaft driving mechanism, and the shaft-like tool is attached to the differential case. The chuck mechanism is configured to be movable back and forth along the rotation axis (L) of the chuck mechanism so as to approach and separate .
The flat cutter conveyance mechanism can hold a flat cutter for spotting a gear flat seat on the inner wall portion of the gear storage chamber of a differential case as a workpiece, and the differential gripped by the chuck mechanism An apparatus for processing an inner surface of a differential case , wherein a flat cutter is carried into a gear housing chamber of the case and a flat cutter is carried out from the gear housing chamber . A differential case inner surface machining apparatus comprising at least a workpiece gripping rotation and shaft drive mechanism (20) and a tool feed mechanism (100) disposed opposite thereto.
The workpiece gripping rotation and shaft drive mechanism (20) is a chuck mechanism that can grip a differential case as a workpiece and can rotate integrally with the differential case with the center line (C) of the differential case as a rotation axis (L). (30) , a workpiece driving means for forcibly rotating the chuck mechanism and the differential case gripped by the chuck mechanism, and a center shaft provided movably along the rotation axis (L) at the center of the chuck mechanism (42) and a shaft drive means (22) for moving the center shaft,
The tool feed mechanism (100) includes a turret head equipped with a flat cutter holding shaft (101) and a long bite (102) as a shaft-like tool that can be disposed opposite to the center shaft of the workpiece gripping rotation and shaft drive mechanism. together are movably configured along the rotational axis (L) of the chuck mechanism in order to close away the shaft-like tool to the differential case,
When the flat cutter holding shaft (101) of the shaft-like tools equipped on the turret head is selected, in the gear housing chamber of the differential case, the center shaft (42) and the flat cutter holding shaft ( 101) and in a state of sandwiching and supporting the flat cutter (202), the three of the center shaft (42), flat cutter (202) and flat cutter holding shaft (101) are synchronously reciprocated, A pair of gear plane seats facing each other on the inner wall of the gear housing chamber of the differential case are countersunk,
When the long tool (102) of the shaft-like tools equipped on the turret head is selected, the center penetrating the two cylindrical portions of the differential case and the gear storage chamber outside the differential case. The tip of the shaft (42) is brought into contact with the tip of the long bite (102), and the two are synchronously moved along the center line (C) of the differential case while maintaining the contact state of both. By cutting the inner peripheral surface of each cylindrical portion of the differential case,
An inner surface processing apparatus for a differential case. The differential case as a workpiece can hold a flat cutter (202) for countersinking the flat seat for gears on the inner wall of the gear storage chamber of the differential case, and the gear storage of the differential case gripped by the chuck mechanism 5. The differential case inner surface processing apparatus according to claim 4, further comprising a plane cutter conveyance mechanism (200) for carrying the plane cutter into the room and carrying out the plane cutter from the gear storage room.

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