JP2008132557A - Inner surface machining device for hollow workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inner surface machining device for a hollow workpiece capable of enhancing the efficiency of working by simplifying the control of a working machine and facilitating its introduction by little remodeling of the working machine. <P>SOLUTION: This inner surface machining device for the hollow workpiece is provided with a holding part for holding cutters 6, 7 to rotate around a central rotation axis X. The holding part has a movable mechanism for positioning the cutters 6, 7 in a working position in the hollow workpiece and an evacuation position outside the hollow workpiece, respectively, and a guide mechanism 32 for guiding the cutters 6, 7 positioned in the working position to move in the direction of central rotation axis X. The guide mechanism 32 includes an energizing means 36a for energizing the cutters 6, 7 onto a retreat side against pressing-in force when the cutters 6, 7 are pressed into an advance side due to advance travel of an internally fitted driving shaft. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for cutting an inner surface of a hollow workpiece.

  Conventionally, for example, as a device for cutting an inner surface of a differential case (hereinafter referred to as a differential case) as one of hollow workpieces, a cutter that is inserted from the opening of the differential case and positioned at a processing position inside the differential case is inserted from the through hole of the differential case. Devices are known that are supported on both sides by two drive shafts inserted inside. In this apparatus, the inner surface of the differential case is cut by rotating the cutter by rotation of the drive shaft.

  However, the processing apparatus has a two-axis configuration including two drive shafts for supporting the cutter, and two axes for rotating the cutter supported by the two drive shafts against the inner surface of the differential case. Therefore, there is a problem that the introduction cost is high because it is designed as a dedicated machine for processing the inner surface of the differential case.

On the other hand, for example, Patent Document 1 discloses a tool for enabling inner surface processing of a differential case using, for example, a general-purpose machining center. This tool is a tool that can be attached to the main spindle of a machining center. The holding mechanism that rotatably holds the cutter, and the central axis of the cutter with the tip of the main spindle (drive shaft attached to the main spindle) fitted inside. A guide mechanism that guides the cutter so as to be movable in the direction, and a compression spring that biases the cutter in the direction opposite to the moving direction when the cutter is pushed in by movement of the main shaft.
JP 2004-106081 A

  However, since the tool disclosed in Patent Document 1 is attached to the spindle of the machining center as described above, the cutter is held on the machining center side. For this reason, when machining the inner surface of the differential case, the main shaft of the machining center is first moved up and down to insert the cutter into the inside of the opening of the differential case, and then the machining center of the machining center is inserted into the through hole of the differential case. Control to move the spindle back and forth must be performed. As such, there is an inconvenience that the machining efficiency of the differential case is reduced because the spindle of the machining center to which the tool is attached has to be moved both vertically and forward and backward.

  Further, in the inner surface processing of the differential case, it is necessary to cut both the planar inner surface that contacts the back surface of the side gear and the spherical inner surface that contacts the rear surface of the pinion. It is necessary to switch the cutter between a flat cutter for processing and a spherical cutter for processing a spherical inner surface.

  Therefore, for example, in the technique of Patent Document 1, a plurality of tools holding each cutter are accommodated in a tool magazine, and a tool attached to the main shaft by an auto tool changer and a tool accommodated in the tool magazine are exchanged. However, since the tool has a special shape including a holding mechanism and a guide mechanism, a general tool such as an auto tool changer or a tool magazine cannot be used. Must be redesigned. Therefore, even the technique disclosed in Patent Document 1 is not easy to introduce.

  The present invention has been made in view of such points, and the object of the present invention is to simplify the control on the processing machine side to increase the processing efficiency, and to eliminate the modification on the processing machine side, and to introduce the introduction. To make it easier.

  According to one aspect of the present invention, an apparatus for processing the inner surface of a hollow work is provided with a tip of a drive shaft attached to a processing machine and moving forward and backward along a predetermined rotation center axis from one side thereof. A cutter that is fitted and rotated by rotation of the drive shaft to cut the inner surface of the hollow workpiece; and a holding unit that holds the cutter rotatably about the rotation center axis.

  The holding portion moves the cutter in a direction orthogonal to the rotation center axis of the drive shaft, thereby passing the cutter through the opening of the hollow workpiece and a processing position on the rotation center axis in the hollow workpiece. A moving mechanism that is positioned at each of the retraction positions outside the hollow workpiece, and a guide mechanism that guides the cutter positioned at the processing position so as to be movable in the direction of the rotation center axis of the drive shaft, The guide mechanism is inserted into the hollow work through a through-hole formed in the hollow work as the drive shaft moves forward, and the drive shaft is located on one side of the cutter positioned at the processing position. And the cutter was pushed to the forward side by further forward movement of the drive shaft. To come, in opposition to the pushing force, including biasing means for biasing said cutter in a retracted side of the drive shaft.

  According to this configuration, the cutter held by the holding unit is positioned at the machining position in the hollow workpiece and the retreat position outside the hollow workpiece by the moving mechanism of the holding unit. That is, since the cutter is moved by a moving mechanism different from the processing machine side, there is no need to move the cutter between the processing position and the retracted position on the processing machine side. It is only necessary to perform the backward movement control. Thus, the processing efficiency of the hollow workpiece is improved by separately performing the forward and backward movement control of the drive shaft and the movement control of the cutter on the processing machine side and the holding unit side.

  In addition, when the drive shaft is moved forward and fitted into one side of the cutter, and when the cutter is pushed and pressed against the inner surface of the hollow workpiece, the urging means of the guide mechanism causes the cutter to resist the pushing force. Power is granted. For this reason, although the said cutter is the state supported by one side by the drive shaft, it is supported stably, and, thereby, processing accuracy improves.

  Furthermore, the processing machine can be a general-purpose processing machine (for example, a machining center) having a single drive shaft, and the drive shaft is simply a drive shaft fitted inside one side of the cutter. For example, general-purpose tools such as auto tool changers and tool magazines can be used, and almost no modification on the processing machine side is required.

  When the drive shaft moves backward after completion of the inner surface processing of the hollow workpiece, the guide mechanism moves the cutter backward and follows the drive shaft by the biasing force by the biasing means. It is preferable that it is positioned at a position where it can move to the retracted position through the opening formed in the.

  By doing so, the drive shaft of the processing machine is only one shaft fitted inside one side of the cutter, but when the drive shaft is moved backward, the cutter is moved backward following the drive shaft. be able to. Further, since the cutter is positioned at a position where it can be moved to the retracted position through the opening of the hollow workpiece, the cutter can be moved out of the hollow workpiece by the moving mechanism. That is, after completion of the inner surface processing of the hollow workpiece, the cutter can be automatically moved out of the hollow workpiece.

  The holding unit may hold each of the plurality of cutters so as to be rotatable around the rotation center axis, and the moving mechanism may position each of the cutters individually at the processing position.

  By doing so, it becomes possible to efficiently execute the inner surface processing of the hollow workpiece while automatically switching a plurality of cutters. Also in this case, since the cutter is switched not on the processing machine side but on the inner surface processing apparatus side (holding portion side), no modification on the processing machine side is required.

  The cutter is a cutter that cuts the inner surface of the hollow workpiece into a spherical shape, and a support bearing protrudes from the side opposite to the one side on which the drive shaft is fitted in the cutter for spherical processing. The spherical processing cutter is inserted into a hole formed in the hollow workpiece when the support shaft is pushed in a forward direction by a drive shaft fitted therein. Both sides may be supported by both the bearing and the drive shaft.

  When the cutter for spherical processing is pressed against the inner surface of the hollow workpiece, the blade surface of the cutter and the inner surface of the hollow workpiece are in spherical contact with each other, so that, for example, vibration or vibration occurs when the cutter is supported on one side by the drive shaft. There is a fear.

  On the other hand, in the above-described configuration, a support bearing is protruded on the side opposite to the side on which the drive shaft is fitted in the spherical processing cutter, and the support bearing is inserted into the hole of the hollow workpiece. By doing so, the cutter for spherical surface processing is supported on both sides by both the support bearing and the drive shaft, so that the above-mentioned shake or the like does not occur. As a result, the accuracy of spherical processing of the hollow workpiece is further improved.

  As described above, according to the present invention, the cutter is held by the holding portion having the moving mechanism, and the cutter is positioned at the processing position and the retracted position by the holding portion, thereby controlling the processing machine side and the holding portion side. These controls can be simplified to improve the machining efficiency.

  Further, by including an urging means in the guide mechanism of the holding portion, a single-axis processing machine can be used, so that a general-purpose processing machine can be used, and for example, an auto tool changer, a tool magazine, etc. Can be diverted, making almost no modification on the processing machine side easy to introduce.

  Furthermore, by applying an urging force to the cutter by the urging means, the inner surface of the hollow workpiece can be processed with high accuracy even when the cutter is supported on one side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows the entire machining center 1 to which a hollow work inner surface processing apparatus 2 according to this embodiment is attached. The machining center 1 is an apparatus for processing the inner surface of a differential case 9 as a hollow work. ing. The machining center 1 uses a commercially available machining center 1, for example, and is a so-called horizontal machining center 1 in which a rotation center axis X of a main shaft extends in a horizontal direction.

  Here, the differential case 9 to be processed will be briefly described with reference to FIGS. In the following, the differential case 9 is defined as front / rear, left / right, and upper / lower with reference to the posture shown in FIG. 2 (based on the initial posture fixed to the workpiece fixing jig 8 described later). To do. That is, the left side of FIG. 7 is the front side, the right side is the rear side, the upper side is the right side, the lower side is the left side, and the plane perpendicular to the plane is the vertical direction. (In FIG. 2, the upper side of the drawing is the upper side of the differential case 9).

  An opening 91 is formed on the upper surface of the differential case 9, and a hollow portion 92 that communicates with the opening and accommodates a gear mechanism (not shown) of the differential device is formed therein. The hollow portion 92 is divided into four front and rear surfaces, and left and right surfaces. Of these, the front and rear surfaces are flat surfaces (hereinafter referred to as these two surfaces) on which the back surface of the side gear included in the gear mechanism abuts. Are referred to as front and rear thrust surfaces 93a and 93b, respectively). On the other hand, the two left and right surfaces are spherical surfaces (hereinafter, these two surfaces are referred to as left and right spherical surfaces 94a and 94b) with which the back surface of the pinion included in the gear mechanism abuts.

  The differential case 9 is also formed with relatively large-diameter through holes 95a and 95b penetrating in the horizontal direction in the respective front and rear sides thereof so as to open at the center positions of the thrust surfaces 93a and 93b. The through holes 95a and 95b are holes through which the left and right drive shafts penetrate in the differential device, and when the inner surface of the differential case 9 is processed, the cutter 6 that performs thrust surfaces 93a and 93b is rotated as described later. This is a hole into which the drive shaft 18 to be inserted is inserted. Hereinafter, the through holes are referred to as thrust surface cutter drive shaft through holes 95a and 95b.

  The differential case 9 is further formed with through holes 96a and 96b having relatively small diameters penetrating in the horizontal direction on the left and right sides of the differential case 9 so as to open at the center positions of the spherical surfaces. The through holes 96a and 96b are holes into which a pinion drive shaft is inserted in the differential device, and when the inner surface of the differential case 9 is processed, a drive shaft 19 that rotates a cutter 7 that performs spherical processing as will be described later. Is a hole to be inserted (see FIG. 10). Hereinafter, the through holes are referred to as spherical cutter drive shaft through holes 96a and 96b.

  The opening 91 is an opening through which a cutter positioned in the hollow portion 92 passes when the inner surface of the differential case 9 is processed.

  Next, a cutter for inner surface processing (cutting) of the differential case 9 will be described. As described above, there are two types of inner surface processing of the differential case 9; cutting processing of the thrust surfaces 93a and 93b (flat surfaces) and cutting processing of the spherical surfaces 94a and 94b. Two types of cutters are attached: a thrust surface cutter 6 for cutting the thrust surfaces 93a and 93b, and a spherical cutter 7 for cutting the spherical surfaces 94a and 94b.

  Among these, as shown in FIGS. 7 and 8, the thrust surface cutter 6 has a substantially cylindrical shape arranged so that its central axis is in the front-rear direction. It has a cut-off shape, and a plurality of blades 61 are attached to the front end surface thereof at equal intervals in the circumferential direction to constitute a blade surface. Further, a concave groove 62 that is recessed inward in the radial direction from the circumferential surface is formed in the front and rear central portions of the thrust surface cutter 6. Furthermore, an engagement recess 63 is formed at the rear end of the thrust surface cutter 6 and opens in the rear end and is recessed radially inward from the upper surface. As will be described later, the engaging recess 63 engages with an engaging pin 39a of the cutter holding portion 3.

  A drive shaft insertion hole 64 that opens to the rear end surface is formed at the center position of the thrust surface cutter 6, and the front end portion of the thrust surface cutter drive shaft 18 is inserted into the drive shaft insertion hole 64. Two key grooves 65 and 65 are formed in the drive shaft insertion hole 64 so as to face each other with the central axis interposed therebetween, and a key (not shown) provided on the thrust surface cutter drive shaft 18 is the key groove 65. , 65, the rotational driving force of the thrust surface cutter drive shaft 18 is transmitted to the thrust surface cutter 6, and the thrust surface cutter 6 rotates about its central axis. The cutter 6 and the drive shaft 18 can be engaged by spline fitting instead of the key and the key grooves 65, 65. Further, the bottom surface of the drive shaft insertion hole 64 is a pressing surface 66 that abuts the front end surface of the thrust surface cutter drive shaft 18 and presses the thrust surface cutter 6 forward.

  On the other hand, as shown in FIGS. 9 and 10, the spherical cutter 7 has a substantially cylindrical shape arranged so that the central axis thereof is in the front-rear direction, and a plurality of blades 71 are provided on the front end surface. By being attached at equal intervals in the circumferential direction, a blade surface having a spherical tip surface is formed. Similarly to the thrust surface cutter 6, a concave groove 72 is formed in the front and rear central portions of the spherical cutter 7 and is recessed inward in the radial direction from the circumferential surface. A concavity 73 is formed.

  A drive shaft insertion hole 74 that opens to the rear end surface is formed at the center position of the spherical cutter 7, and the front end portion of the spherical cutter drive shaft 19 is inserted into the drive shaft insertion hole 74. Two key grooves 75 and 75 are formed in the drive shaft insertion hole 74 so that a key (not shown) provided on the spherical cutter drive shaft 19 is engaged with the key grooves 75 and 75. As a result, the rotational driving force of the spherical cutter drive shaft 19 is transmitted to the spherical cutter 7, and the spherical cutter 7 rotates about its central axis. The cutter 7 and the drive shaft 19 can be engaged by spline fitting instead of the key and the key grooves 75 and 75. Further, the bottom surface of the drive shaft insertion hole 74 is a pressing surface 76 that abuts the front end surface of the spherical cutter drive shaft 19 and presses the spherical cutter 7 forward.

  Further, a support bearing 77 that can rotate around the central axis is fixed to the spherical cutter 7 so as to protrude forward from the blade surface. As will be described in detail later, the support bearing 77 is inserted into the spherical cutter drive shaft through holes 96a and 96b when the inner surface of the differential case 9 is processed as shown in FIG. Thus, the spherical cutter 7 is supported on both the front and rear sides thereof by both the support bearing 77 and the spherical cutter drive shaft 19.

  The machining center 1 includes a base 11 extending in the front-rear direction (left-right direction in FIG. 1), and a main body placed on one end side of the base 11 (right side in FIG. 1, hereinafter referred to as the rear side). Part 12.

  The main body 12 has a main shaft 13 that can be rotated about a rotation center axis X extending in the horizontal direction and to which a thrust surface cutter drive shaft 18 and a spherical cutter drive shaft 19 are attached, and various types including the drive shafts described above. A tool magazine 14 in which a tool is accommodated, and each tool accommodated in the tool magazine 14 are attached to the main shaft 13, and a tool attached to the main shaft 13 is replaced with a tool accommodated in the tool magazine 14. And an auto tool changer 15.

  The main body 12 is movable back and forth by a guide rail 16 attached on the base 11. The main shaft 13 is movable up and down by a guide rail 17 attached to the main body 12. For this reason, the main shaft 13 can be moved forward and backward and vertically (see the two-dot chain line in the figure).

  The inner surface processing device 2 is installed at a position on the other end side (the left side in FIG. 1, hereinafter referred to as the front side) on the base 11 relative to the main body portion 12 of the machining center 1 in the front-rear direction. ing. In addition, a turntable 20 that rotates about a rotation axis Z extending in the vertical direction is also disposed at the front side position on the base 11, and a workpiece fixing that holds the differential case 9 to be processed on the turntable 20. A jig 8 is provided.

  As shown in FIGS. 2 and 3, the workpiece fixing jig 8 includes an insertion hole 81 into which a differential case 9 to be processed is inserted and fixed, and the differential case 9 is inserted into the insertion hole 81. Then, the opening 91 is made upward and the thrust surface cutter drive shaft through holes 95a and 95b are opened in the front-rear direction. The thrust surfaces 93 a and 93 b of the differential case 9 are orthogonal to the rotation center axis X of the main shaft 13 of the machining center 1.

  The workpiece fixing jig 8 also has a notch groove extending rearward from the front end thereof so that the spherical cutter drive shaft through holes 96a and 96b of the differential case 9 are exposed laterally on the left and right sides thereof. 82 is formed, and a communication hole 83 communicating with the opening 91 is formed in the upper portion thereof so as to open to the upper surface.

  Since the workpiece fixing jig 8 is fixed on the turntable 20 as described above, by rotating the turntable 20, two thrust surfaces 93a in the differential case 9 fixed to the workpiece fixing jig 8 are provided. A total of four surfaces 93b and two spherical surfaces 94a and 94b are positioned at positions orthogonal to the rotation center axis X of the main shaft 13 of the machining center 1 as processing target surfaces.

  2 to 6, the inner surface processing apparatus 2 is supported by leg portions 27 arranged on both the left and right sides of the turntable 20, and is erected at a front position of the workpiece fixing jig 8. A frame 21, a subframe 22 supported by the main frame 21, and a cutter holder 3 supported by the subframe 22 are provided.

  On the rear surface side of the main frame 21, two guide rails 23a, 23a extending in the left-right direction with a predetermined interval in the vertical direction are attached.

  On the other hand, on the front side of the sub-frame 22, two guides 23b, 23b arranged at predetermined intervals in the vertical direction are attached, and each guide 23b is related to each guide rail 23a of the main frame 21. By combining, the sub-frame 22 is supported with respect to the main frame 21.

  A cylinder 24 extending in the horizontal direction is attached to the right side portion of the main frame 21, and the tip of the cylinder rod 24a of the cylinder 24 passes through an intermediate position between the two guide rails 23a and 23a, It is fixed to the right side of the frame 22. By driving the cylinder 24 to extend and contract, the sub-frame 22 supported by the main frame 21 via the guide rails 23 a and 23 b moves in the left-right direction relative to the main frame 21.

  On the rear surface side of the sub-frame 22, two guide rails 25a and 25a extending in the vertical direction with a predetermined interval in the left-right direction are attached.

  On the other hand, two guides 25b, 25b arranged at a predetermined interval in the left-right direction are attached to the front surface side of the cutter holding portion 3, and each guide 25b is attached to each guide rail 25a of the subframe 22. By engaging, the cutter holder 3 is supported with respect to the subframe 22.

  A cylinder 26 extending in the vertical direction is attached to the upper portion of the subframe 22. Further, the cutter holding portion 3 is provided with a cylinder rod fixing portion 31 that protrudes forward through the two guide rails 25a, 25a and thereby is located in the subframe 22, and the cylinder The tip ends of the 26 cylinder rods 26 a are fixed to the cylinder rod fixing portion 31. By extending and retracting the cylinder 26 by this, the cutter holder 3 supported by the subframe 22 via the guide rail 25a and the guide 25b moves relative to the subframe 22 in the vertical direction. Become.

  Accordingly, the cutter holder 3 is movable up and down and left and right relative to the main frame 21, and the guide rail 23 a and the cylinder 24 of the main frame 21 and the guide rail 25 a of the subframe 22. The cylinder 26 constitutes a moving mechanism 4 that positions a plurality of cutters individually at a machining position in the differential case and a retracted position outside the differential case, as will be described later.

  The cutter holding unit 3 includes two guide mechanisms 32 and 32 that are arranged at predetermined intervals in the left-right direction and extend rearward, and the thrust surface cutter 6 is provided in one guide mechanism 32. The spherical guide 7 is held on the other guide mechanism 32. Therefore, by moving the cutter holder 3 in the left-right direction, the thrust surface cutter 6 held by one guide mechanism 32 and the spherical cutter 7 held by the other guide mechanism 32 are selectively fixed to the workpiece. It will be positioned above the tool 8.

  As shown in FIGS. 5 and 6, each guide mechanism 32 is arranged with two support rods 33, 33 extending in the front-rear direction with a predetermined interval in the left-right direction, and with a predetermined interval in the front-rear direction. A rod holding portion 34 for holding each support rod 33 at two positions on the front and rear sides, and a cutter holding portion 35 fixed to the support rod 33 at a substantially intermediate position on the support rod 33 at the front and rear. .

  Each of the support rods 33 is held so as to be movable in the front-rear direction with respect to the rod holding part 34, and the cutter holding part 35 is also moved in the front-rear direction as the support rod 33 moves back and forth. (Refer to the one-dot chain line in FIG. 5).

  Further, the rod holding portion 34 disposed on the front side is attached with a cylindrical spring support member 36 whose rear end is opened and the front end portion of the support rod 33 is inserted and whose front end is closed, The spring support member 36 is inserted with a compression spring 36a as an urging means that abuts the front end surface of the support rod 33 and urges the support rod 33 and the cutter holding portion 35 rearward. Yes.

  On the other hand, a stopper 37 is fixed to the rod holding portion 34 disposed on the rear side, and the cutter holding portion 35 urged rearward by the compression spring 36 a comes into contact with the stopper 37. The initial position is defined (see the solid line in FIG. 5). As will be described later, this initial position is a position where the cutters 6 and 7 are on the center line of the opening 91 of the differential case 9 (the communication hole 83 of the workpiece fixing jig 8) (see FIG. 2). Reference numeral 33a denotes a proximity switch fixed to the rod holding portion 34. By detecting the rear end surface of the support rod 33 by the proximity switch 33a, the cutter holding portion 35 is positioned at the initial position. I try to detect that.

  The cutter holding portion 35 is provided at a fixed portion 35a fixed to the support rod 33, an extended portion 35b extending downward from the fixed portion 35a, and a lower end of the extended portion 35b, and the thrust surface. And a bearing portion 38 that supports the cutter 6 and the spherical cutter 7 so as to be rotatable around the central axis. Of these, the bearing portion 38 is composed of a halved first bearing portion 38a formed integrally with the extending portion 35b and a halved second bearing portion 38b, and the first and second bearings. By fixing the portions 38a, 38b to each other in a state where they are positioned in the concave grooves 62, 72 of the cutters 6, 7, the cutters 6, 7 are held so as to be rotatable around the central axis.

  A cutter engaging portion 39 extending downward along the extending portion 35 b of the cutter holding portion 35 is moved up and down relative to the cutter holding portion 35 on the rear side of the cutter holding portion 35. It is attached to the cutter holding part 3 so that it becomes possible. At the lower end of the cutter engaging portion 39, an engaging pin 39a that engages with the engaging recess of each cutter 6 and 7 is attached, and this engaging pin 39a is connected to the engaging recess 63 of each cutter 6 and 7. 73, the rotational positions of the cutters 6 and 7 are restricted, whereby the key grooves 65 and 75 of the cutters 6 and 7 and the keys of the drive shafts 18 and 19 can be aligned. I am doing so.

  The cutter engaging portion 39 is also integrally attached with an abutting portion 39b that protrudes forward and abuts against the abutting portion 22a fixed to the subframe 22, and has moved the cutter holding portion 3 downward. When the abutting portion 39b sometimes abuts against the contact portion 22a (see the two-dot chain line in FIG. 5), the downward movement of the cutter engaging portion 39 is stopped, while the cutter holding portion 35 is further lowered. By moving, the engagement pin 39a and the engagement recesses 63 and 73 of the cutters 6 and 7 are disengaged, whereby the cutters 6 and 7 are accommodated in the differential case 9 so as to be rotatable around the central axis. It has come to be.

  Control of the machining center 1 with the inner surface machining apparatus 2 configured as described above will be described with reference to the flow shown in FIG.

  First, the differential case 9 to be processed is fixed by the workpiece fixing jig 8, and the thrust surface cutter drive shaft through-holes 95a and 95b of the differential case 9 are formed so that one of the thrust surfaces 93a thereof becomes the processing target surface. The rotational position of the turntable 20 is set at a position where the central axis of the main shaft 13 is coaxial with the central axis of the main shaft 13 of the machining center 1.

  In step S <b> 1, with the thrust surface cutter 6 positioned at the upper position of the workpiece fixing jig 8, the cutter holding unit 3 is lowered, thereby positioning the thrust surface cutter 6 at the processing position in the differential case 9. At this time, as described above, the engaging pin 39a is disengaged from the engaging recess 63 of the cutter 6 so that the thrust surface cutter 6 can rotate around its central axis.

  In the subsequent step S2, the main body 12 is advanced with the thrust surface cutter drive shaft 18 attached to the main shaft 13 of the machining center 1. In step S3, the thrust surface cutter drive shaft 18 is inserted into the thrust surface cutter drive shaft through hole 95b of the differential case 9, and the front end of the drive shaft is inserted into the drive shaft insertion hole 64 of the thrust surface cutter 6. Insert it. At this time, the rotational position of the thrust surface cutter drive shaft 18 is preset at a position where the key matches the key groove 65 of the cutter 6, whereby the drive shaft front end is inserted into the drive shaft of the thrust surface cutter 6. It can be inserted into the hole 64.

  Then, if the thrust surface cutter drive shaft 18 is inserted into the cutter 6, in step S4, the main shaft 13 is rotated to rotate the thrust surface cutter 6 and the drive shaft 18 is further advanced. As shown, the blade surface of the thrust surface cutter 6 is pressed against the thrust surface 93a of the differential case 9 to cut the thrust surface 93a. At this time, since the thrust surface cutter 6 and the cutter holding portion 35 move forward, the thrust spring 6a of the guide mechanism 32 applies a rearward biasing force to the thrust surface cutter 6 and the cutter holding portion 35. Is granted. Although the thrust surface cutter 6 is supported on one side by the thrust surface cutter drive shaft 18, the urging force is applied to the cutter 6, so that the cutter 6 is stably supported and the processing accuracy is improved. Can be made.

  When the machining is completed, the thrust surface cutter drive shaft 18 is moved backward in step S5. At this time, the thrust surface cutter 6 moves backward together with the drive shaft by the urging force of the compression spring 36a, and the cutter holding portion 35 abuts against the stopper 37, whereby the backward movement of the thrust surface cutter 6 stops. The thrust surface cutter drive shaft 18 is further retracted until its front end is outside the differential case 9. Further, the rotation of the thrust surface cutter drive shaft 18 is stopped at a predetermined rotation angle by the control on the machining center 1 side, whereby the engagement recess 63 of the thrust surface cutter 6 is positioned at a rotation position that opens upward. .

  In step S6, the cutter holder 3 is raised. Since the position at which the thrust surface cutter 6 stops as described above is a position corresponding to the opening 91 of the differential case 9, the thrust surface cutter 6 moves out of the differential case 9 through the opening 91. . At this time, the engaging pin 39a is inserted into the engaging recess 63 of the thrust surface cutter 6, and the thrust surface cutter 6 is fixed at a predetermined rotational position.

  Then, it is determined in step S7 whether the thrust surfaces 93a, 93b have been processed twice, that is, whether each of the two thrust surfaces 93a, 93b has been performed. If YES, the process proceeds to step S9. If NO, the turntable 20 is rotated 180 ° in step S8. As a result, the other thrust surface 93b becomes the surface to be processed, and steps S1 to S6 are executed on the thrust surface 93b. Since the rotational position of the thrust surface cutter 6 is defined, the thrust surface cutter drive shaft 18 can be inserted into the drive shaft insertion hole 64 of the thrust surface cutter 6 even in the second time.

  Thus, when the processing of the two thrust surfaces 93a and 93b is completed (YES in step S7), the turntable 20 is rotated by 90 ° in step S9. Thereby, the central axis of the through-holes 96a and 96b for the spherical cutter drive shaft of the differential case 9 is positioned so as to be coaxial with the central axis of the main shaft 13 of the machining center 1, and the one spherical surface 94a is set as the processing target surface.

  In the subsequent step S10, the spherical cutter 7 is positioned above the workpiece fixing jig 8 by moving the cutter holder 3 in the left-right direction, and in that state, the cutter holder 3 is lowered in step S11. The spherical cutter 7 is positioned at the processing position in the differential case 9. Also at this time, the engaging pin 39a is disengaged from the engaging recess 73 of the cutter 7, so that the spherical cutter 7 is rotatable around its central axis.

  Next, in step S12, the spherical cutter drive shaft 19 is attached to the main shaft 13 of the machining center 1 by the auto tool changer 15, and the drive shaft 19 is advanced. In step S13, the drive shaft front end is inserted into the drive shaft insertion hole 74 of the spherical cutter 7. At this time, the rotational position of the spherical cutter drive shaft 19 is set in advance to a position where the key matches the key groove 75 of the cutter 7, whereby the front end portion of the drive shaft is the drive shaft insertion hole 74 of the spherical cutter 7. Can be inserted into.

  If the spherical cutter drive shaft 19 is inserted into the cutter 7, in step S14, the main shaft 13 is rotated to rotate the spherical cutter 7, and the drive shaft 19 is further advanced, as shown in FIG. The blade surface of the spherical cutter 7 is pressed against the spherical surface 94a of the differential case 9 to cut the spherical surface 94a. At this time, since the spherical cutter 7 and the cutter holding portion 35 are moved forward, the spherical cutter 7 and the cutter holding portion 35 are given a rearward urging force by the compression spring 36a of the guide mechanism. The Further, the support bearing 77 of the spherical cutter 7 is inserted into the spherical cutter drive shaft through hole 96 a of the differential case 9, and the spherical cutter 7 is supported by both the support bearing 77 and the spherical cutter drive shaft 19. Both front and rear sides are supported.

  The thrust surface cutter 6 and the thrust surface 93a, 93b of the differential case 9 are relatively stable because the planes orthogonal to the rotation center axis of the main shaft 13 are in contact with each other, whereas the spherical surface 7a of the spherical cutter 7 and the differential case 9 94b, since the spherical surfaces abut each other, for example, blurring is likely to occur. However, since the spherical cutter 7 is supported by the support bearing 77 on the abutting side with the spherical surfaces 94a, 94b of the differential case 9, such blurring occurs. Etc. are prevented. As a result, the processing accuracy of the spherical surfaces 94a and 94b can be improved.

  When the machining is completed, the spherical cutter drive shaft 19 is moved backward in step S15. At this time, the spherical cutter 7 is moved backward together with the drive shaft 19 by the urging force of the compression spring 36a, and the cutter holder 35 abuts against the stopper 37, so that the backward movement of the spherical cutter 7 is stopped. The spherical cutter drive shaft 19 is further retracted until its front end is outside the differential case 9. Further, the rotation of the spherical cutter drive shaft 19 is stopped at a predetermined rotation angle by the control on the machining center 1 side, so that the engagement recess 73 of the spherical cutter 7 is positioned at a rotation position opened upward.

  In step S <b> 16, the spherical cutter 7 is moved out of the differential case 9 through the opening 91 by raising the cutter holder 3. At this time, the engaging pin 39a is inserted into the engaging recess 73 of the spherical cutter 7, and the spherical cutter 7 is fixed at a predetermined rotational position.

  Then, it is determined whether or not the spherical surfaces 94a and 94b have been processed twice in step S17, that is, whether the spherical surfaces 94a and 94b are respectively processed. If NO, the turn is determined in step S18. The table 20 is rotated 180 °. As a result, the other spherical surface 94b becomes the surface to be processed, and steps S11 to S16 are performed on the spherical surface 94b. Since the rotational position of the spherical cutter 7 is defined, the spherical cutter drive shaft 19 can be inserted into the drive shaft insertion hole 74 of the spherical cutter 7 even in the second time.

  Thus, when the processing of the two spherical surfaces 94a and 94b is completed (YES in step S17), in step S19, the machining center 1 and the inner surface processing device 2 are returned to their original positions, thereby the differential case. All the inner surface machining of 9 is completed.

  As described above, in this configuration, the thrust surface cutter 6 and the spherical cutter 7 are held by the cutter holding portion 3 of the inner surface processing device 2 which is a device different from the machining center 1, and the cutter holding portion 3 The cutters 6 and 7 are positioned at a processing position in the differential case 9 and a retracted position outside the differential case 9. Therefore, it is not necessary to move the cutters 6 and 7 between the machining position and the retracted position on the machining center side, and the machining center 1 only needs to perform forward and backward movement control of the drive shafts 18 and 19. As described above, the four inner surfaces 93a, 93b, 94a, and 94b are processed for one differential case 9, and the drive shafts 18 and 19 are moved forward and backward at least four times. By moving up and down at least four times, the forward and backward movement control of the drive shafts 18 and 19 and the upward and downward movement control of the cutters 6 and 7 are separately performed on the machining center side and the inner surface processing apparatus side. , Processing efficiency is improved.

  Further, in the above-described configuration, the commercially available machining center 1 is diverted, and the drive shafts 18 and 19 are shafts that are simply inserted into the cutters 6 and 7, respectively. For example, the auto tool changer 15 or the tool magazine As for 14 etc., a general purpose thing can be diverted as it is. As a result, almost no modification on the machining center 1 side is required.

  Furthermore, although the thrust surface cutter 6 is only supported on one side by the drive shaft 18 of the machining center 1, the thrust surface cutter 6 is stabilized by being given a biasing force by the compression spring 36a attached to the guide mechanism 32. Therefore, high-precision cutting is possible. On the other hand, since both sides of the spherical cutter 7 are supported by the drive shaft 19 and the support bearing 77 of the machining center 1, the cutter 7 can be supported more stably and high-precision cutting can be performed.

  Further, when the drive shafts 18 and 19 are moved backward, the cutters 6 and 7 can be moved backward following the drive shafts 18 and 19 by the biasing force of the compression spring 36a. 7 can be positioned at a position where it can be moved out of the differential case 9 through the opening 91.

  In addition, since the cutter holding unit 3 can hold the plurality of cutters 6 and 7 and individually position the cutters 6 and 7 at the processing positions in the differential case 9, as described above, The inner surface machining of the differential case 9 can be efficiently executed while automatically switching 7.

  In the above-described embodiment, the cutter holding unit 3 holds two cutters, the thrust surface cutter 6 and the spherical cutter 7. However, the number of cutters held by the cutter holding unit 3 is not particularly limited.

  Further, although no support bearing is attached to the thrust surface cutter 6, a support bearing may be attached to the thrust surface cutter 6 as well as the spherical cutter 7.

  Furthermore, the processing machine to which the inner surface processing apparatus 2 of the present invention can be applied is not limited to the horizontal machining center 1, and may be applied to, for example, the vertical machining center 1. In addition, the processing machine is not limited to the machining center 1 and can be widely applied to a single-axis processing machine.

  Further, the hollow workpiece to be processed by the inner surface processing apparatus 2 of the present invention is not limited to the differential case 9.

  As described above, the present invention can use a general-purpose processing machine such as a machining center to process the inner surface of a hollow workpiece with high accuracy and efficiency, and hardly requires modification of the general-purpose processing machine. Therefore, it is useful as an apparatus for cutting an inner surface of a hollow work such as a differential case with a cutter.

1 is an overall view of a machining center with an inner surface processing apparatus. It is a side view of an inner surface processing apparatus. It is a front view of an inner surface processing apparatus. It is a top view of an inner surface processing apparatus. It is a side view which expands and shows the cutter holding part of an inner surface processing apparatus. It is a rear view which expands and shows the cutter holding part of an inner surface processing apparatus. It is plane explanatory drawing which shows the state of the process by a thrust surface cutter. It is a rear view of a thrust surface cutter. It is plane explanatory drawing which shows the state of the process by a spherical cutter. It is a rear view of a spherical cutter. It is a flowchart which concerns on the process control of the machining center with an internal surface processing apparatus.

Explanation of symbols

1 Machining center (processing machine)
2 Internal processing equipment (holding part)
18 Thrust surface cutter drive shaft 19 Spherical cutter drive shaft 3 Cutter holder 32 Guide mechanism 36a Compression spring (biasing means)
37 Stopper 4 Moving mechanism 6 Thrust surface cutter 7 Spherical cutter 77 Support bearing 9 Differential case (hollow workpiece)
X rotation center axis

Claims (4)

An apparatus for processing the inner surface of a hollow workpiece,
A front end of a drive shaft that is attached to a processing machine and moves forward and backward along a predetermined rotation center axis is fitted from one side and rotated by the rotational drive of the drive shaft, thereby rotating the inner surface of the hollow workpiece. A cutter for cutting,
A holding part that holds the cutter rotatably about the rotation center axis,
The holding part is
By moving the cutter in a direction perpendicular to the rotation center axis of the drive shaft, the cutter is moved through the opening of the hollow workpiece and the processing position on the rotation center axis in the hollow workpiece and the outside of the hollow workpiece. A moving mechanism positioned at each of the retreat positions of
A guide mechanism that guides the cutter positioned at the processing position so as to be movable in the direction of the rotation center axis of the drive shaft,
The guide mechanism is inserted into the hollow work through a through-hole formed in the hollow work as the drive shaft moves forward, and is driven to one side of the cutter positioned at the processing position. When the shaft is fitted and the cutter is pushed toward the forward side by further forward movement of the drive shaft, the cutter is biased toward the backward side of the drive shaft against the pushing force. An internal surface processing apparatus for a hollow work including an urging means. In the internal processing apparatus of the hollow workpiece of Claim 1,
When the drive shaft moves backward after completion of the inner surface processing of the hollow workpiece, the guide mechanism moves the cutter backward and follows the drive shaft by the biasing force of the biasing means. An inner surface machining apparatus for a hollow workpiece, which is positioned at a position that can be moved to the retracted position through an opening formed in the inner wall. In the inner surface processing apparatus of the hollow workpiece according to claim 1 or 2,
The holding unit holds each of the plurality of cutters so as to be rotatable around the rotation center axis,
The moving mechanism is an inner surface machining apparatus for a hollow workpiece that positions the cutters individually at the machining position. In the inner surface processing apparatus of the hollow workpiece according to any one of claims 1 to 3,
The cutter is a cutter that cuts the inner surface of the hollow workpiece into a spherical shape,
The spherical processing cutter has a support bearing projecting on the side opposite to the side on which the drive shaft is fitted,
When the spherical processing cutter is pushed forward by a drive shaft fitted therein, the support bearing is inserted into a hole formed in the hollow workpiece so that the support bearing and the drive shaft are inserted. A hollow work inner surface processing device supported on both sides by both.

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