JP5288994B2 - Cutting tools - Google Patents

Description

  The present invention relates to a cutting tool that is mounted on a spindle of a machine tool and incorporates a differential transmission mechanism and a cam, and particularly relates to a cutting tool that is applied to cutting of a tapered inner peripheral surface of a valve seat or the like. .

  One method of cutting the tapered inner peripheral surface of a valve seat or the like is a method of turning using an inner diameter tool. This method is a method in which a workpiece held by a lathe chuck is rotated and machining is performed without rotating the inner diameter tool. In the method by turning, there is a problem that the size of the workpiece is limited because a large workpiece cannot be held by the chuck. As another method, there is a method of performing a rolling process by rotating a tool clamped to a spindle with respect to a workpiece fixed on a table in a machining center. In the method using the rolling process, it is possible to perform machining using an overall tool or the like.

  Although it is not a cutting tool applied to the taper inner peripheral surface of a valve seat or the like, an example of a cutting tool incorporating a differential transmission mechanism and a cam is disclosed in Patent Document 1. Patent Document 1 discloses a recessing tool that is applied to an inner diameter grooving process. The recessing tool is a simple differential mechanism that uses only a spur gear combination without rotating the tool body by a complicated worm gear mechanism, etc. Then, the cutting blade is cut into the inner surface of the hole of the workpiece by sliding the holder by the guide of the cam, and an inner peripheral groove is formed on the inner surface of the hole.

  In the 30th to 44th lines of the third column of Patent Document 1, as a description of the configuration of the differential transmission mechanism, “the fixed gear 11 is fixed to the second stage of the stepped shaft of the main body 1, The left tooth of the intermediate gear 14 fitted through the needle roller bearing 13 to the gear shaft 12 screwed to the rear flange 3 in parallel with the axis of the main body 1 meshes with the fixed gear 11. The left tooth approaches the fixed gear 11 and meshes with a differential gear 16 that is loosely fitted together with the thrust ring 15. The differential gear 16 is in constant contact with the end face of the thrust ring 15 and serves as a cushion. "A part of the right side surface of the differential gear 16 ... meshes with the clutch teeth". Further, in the 6th to 18th lines in the fourth column of Patent Document 1, as an explanation of the cam mechanism, “the cam 19 is provided with a shifter groove and a left stepped step of the slide rail board 5 on its stepped outer diameter. A cam groove made of an Archimedes curve is engraved on the right end face of the inner diameter of the head, and in this embodiment, the head is raised and lowered twice in one rotation, and the rise is gently lowered. ..A blind hole that is equally spaced by two on the left side of the head of the slide rail board 5 opposite to this and that touches the inner diameter is formed, and the reset cam 25 is inserted into the hole. Yes.

  In the 15th to 23rd lines of the sixth column of Patent Document 1, as an explanation of the operation of the differential transmission mechanism, “the rotation of the fixed gear 1 of the main body 1 via the intermediate gear 14 is different. In this case, the tooth size or module is changed in the combination of the fixed gear 11 and the left tooth of the intermediate gear and the right tooth of the differential gear 16 and the intermediate gear 14, and each combination is changed. The rotation of the differential gear 16 is slightly delayed from the fixed gear 11 by changing the knitting number of teeth as an isocenter. "

Japanese Utility Model Publication No. 63-17602

  However, when a rolling process is performed using a general-purpose tool, there is a concern that chattering may occur due to a relatively large cutting resistance due to multipoint contact. When chattering occurs, chatter marks are formed on the taper inner peripheral surface, and in the case of the valve seat portion, there is a problem that a gap is formed between the valve and the taper inner peripheral surface, which impairs intake and exhaust performance.

  The present invention provides a cutting tool for turning that can perform high-precision machining with low cutting resistance by moving the cutting edge along with the rotation of the spindle of the machine tool by the built-in differential transmission mechanism and cam mechanism. The purpose is to provide.

In order to achieve the above object, according to the present invention, in a cutting tool mounted on a main shaft of a machine tool and incorporating a differential transmission mechanism and a cam, the input shaft is mounted on the main shaft, the input shaft An input shaft having the cam in which a cam groove is formed on a front end surface, and an output shaft that rotates at a rotational speed different from the input shaft by the differential transmission mechanism, An output shaft disposed coaxially with the input shaft, a cutting blade, and a slider provided on the output shaft, the cam follower engaging with the cam groove, and the cam follower in the cam groove A cutting tool comprising: a slider that moves in a direction inclined with respect to the rotation axis of the main shaft by being guided and moved; and a guide portion that guides the slider in a direction oblique to the axis of the main shaft. Will be provided

According to another aspect of the present invention, the slider includes a driving slider which moves in a direction perpendicular to the axis of rotation, driven to move in a direction inclined relative to the axis of rotation engaged in the drive slider A first guide portion that guides the drive slider in a direction orthogonal to the rotation axis, and guides the driven slider in a direction inclined with respect to the rotation axis of the main shaft. A second guide part. Moreover, according to the other aspect of this invention, it can also have a mounting part which mounts the hole processing tool which processes the hole of the direction of the said rotating shaft line to the front end side of the said output shaft.

  As described above, according to the cutting tool of the present invention, the differential transmission mechanism causes a difference in rotational speed between the input shaft and the output shaft, and is induced in the cam groove by the difference in rotational speed between the input shaft and the output shaft. When the cam follower moves, the slider is guided in the guide portion and moves in a direction inclined with respect to the rotation axis. As a result, the inner peripheral surface of the tapered hole can be processed with a single point contact with a low cutting resistance and high accuracy by the cutting edge provided in the slider. The slider is divided into a drive slider that slides in a direction perpendicular to the rotation axis and a driven slider that is coupled to the drive slider and slides in a direction inclined with respect to the rotation axis. By guiding with the guide portion and guiding the driven slider with the second guide portion, the driving slider and the driven slider can be guided with high accuracy, and high-precision cutting can be performed. If a hole machining tool is attached to the tip end side of the output shaft, a high degree of coaxiality can be obtained by simultaneously machining the hole machining and the inner circumferential surface of the tapered hole.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a cutting tool according to the present invention. A cutting tool according to the present invention is used by being mounted on a spindle head of a machining center, and has a taper portion mounted on a spindle at one end and a tool body (input shaft) having a shaft portion at the other end. In order to move the output shaft mounted on the shaft portion, the differential transmission mechanism that transmits the rotation of the tool body to the output shaft, and the slider provided at the end of the output shaft in a direction inclined with respect to the rotation axis of the main shaft Cam mechanism and guide mechanism. That is, the cutting tool according to the present invention moves the slider provided at the end of the output shaft in a direction inclined with respect to the rotation axis by the cooperation of the differential transmission mechanism, the cam mechanism, and the guide mechanism, thereby tapering the workpiece. The inner peripheral surface of the hole is cut (see FIG. 6). The form of the slider is not limited and may be a separated type or an integrated type. The separation type slider is described in the present embodiment, and the integral type slider is shown in FIG. 4 as a modification of the present embodiment. Moreover, the cutting tool of the present invention can cut the valve seat surface of the combustion chamber of the engine or the mixing chamber of the compressor with high accuracy as an example. However, the cutting tool is not limited to this, and is widely used for cutting the inner peripheral surface of the tapered hole. Applicable.

  FIG. 1 shows a cutting tool 1 of the present embodiment that is mounted on a spindle head 2. The spindle head 2 of the present embodiment can supply coolant in a spindle through manner. The coolant passes through the inside of the tool body 3 and is discharged from the discharge port at the tip of the output shaft 10. The life of the cutting edge can be extended by the cooling action of the coolant, the finished surface can be made good by the lubricating action of the coolant, and the chip disposal can be improved by the pressure of the coolant. The pressure of the coolant is arbitrary, but the above effect can be enhanced by discharging the coolant at a high pressure.

  Although the tool main body 3 has the short taper part 5 at one end and is held by two-sided restraint by the tapered hole inner surface 4a and the end surface 4b of the spindle 2a of the machining center, it is not limited to this. For example, instead of the short taper portion 5, a long taper portion may be formed so that the taper hole inner surface 4 a of the spindle head 2 is constrained on one surface. When the tool body 3 is constrained by two surfaces as in the present embodiment, the rigidity of the tool 1 is increased, and high-precision processing can be performed. The tool body 3 is formed with a flange portion 6 having an outer peripheral groove 6 a having a V-shaped cross section following the short taper portion 5. An ATC arm of a tool changer is engaged with the outer peripheral groove 6a, and the tool body 3 is gripped. The shaft portion 7 formed on the tip side of the tool body 3 is rotatably supported by a pair of bearings 23 and 24 inside the tool housing 22. A cam 33 constituting a cam mechanism is provided at the tip of the shaft portion 7 coaxially with the shaft portion 7.

  A plurality of oil seals 41, 42, 43 are disposed on both sides of the pair of bearings 23, 24. The oil seals 41, 42, 43 are disposed between the tool body 3 and the tool housing 22, and between the oil seal case 44 and the output shaft 10. Sealed to prevent coolant and chips from entering. An oil seal 41 provided on the spindle head 2 side seals between the tool housing 22 and the shaft portion 7 of the tool body 3, and a pair of oil seals 42 and 43 provided on the distal end side of the shaft portion 7 includes The space between the oil seal case 44 and the output shaft 10 is sealed.

Between the pair of bearings 23, 24, an input gear 26 fixed to the outer peripheral surface of the shaft portion 7 of the tool body 3 and an output gear 27 fixed to the outer peripheral surface on the end portion side of the output shaft 10 are mutually connected. They are located apart. As the input gear 26 and the output gear 27, a shift gear having the same outer diameter, tooth width, etc. can be used except that the number of teeth is different between the two gears 26, 27. The input gear 26 and the output gear 27 mesh with the transmission gear 28 so that the rotation of the tool body 3 is transmitted to the output shaft 10. The transmission gear 28 is supported by a pair of bearings 46 and 47 and rotates around the transmission gear shaft 48. The input gear 26, the output gear 27, and the transmission gear 48 are components of the differential transmission mechanism. According to the differential transmission mechanism, the rotational speed of the tool body 3 as the input shaft and the output shaft 10 as the output shaft is changed by engaging the transmission gear 48 with the input gear 26 and the output gear 27 having different numbers of teeth. be able to. That is, when the number of teeth of the input gear 26 and a, if the number of teeth of the output gear 27 and is b, the gear ratio of the output shaft is rotated to become the a / b, the spindle at a rotational speed N _S, The rotational speed N _O of the output shaft is N _O = N _S × (a / b). For this reason, by making the number of teeth of the input / output gears 26 and 27 slightly different, a slight rotational speed difference can be generated between the input shaft and the output shaft. For example, when the number of teeth of the input gear 26 is 149 and the number of teeth of the output gear 27 is 150, when the input shaft is rotated 150 times, the output shaft rotates 149, and the input shaft rotates one rotation relative to the output shaft. You can rotate a lot. As will be described later, the cam follower 19 is formed along the cam groove 37 (see FIG. 5) provided in the cam 33 by rotating the cam 33 provided at the tip of the shaft portion 7 of the tool body 3 relatively once. Thus, the drive slider 60 can be reciprocated once in the radial direction.

  The cam 33 has a head portion 35 and a handle portion 36 to form a stepped columnar shape, and the handle portion 36 is coaxial with the shaft portion 7 in a hole portion 8 a formed on the distal end side of the shaft portion 7 of the tool body 3. Is removably inserted. The cam 33 has a through hole 38 through which coolant passes from one end to the other end in the axial direction. The cam 33 is fixed to the hole portion 8 a by engaging the tip of a set screw 39 screwed into the screw hole 8 b of the shaft portion 7 with the locking hole 36 a of the handle portion 36. In a state where the cam 33 is fixed to the shaft portion 7, the vertical surface of the head portion 35 comes into contact with the tip surface of the shaft portion 7. As shown in FIG. 5, a cam groove 37 with which the cam follower 19 is engaged is formed on the distal end surface of the head portion 35.

  The cam follower 19 that engages with the cam groove 37 has a pin shape, and the base side is perpendicular to the moving direction of the drive slider 60 and is integrally fixed to the side surface of the drive slider 60 by press fitting or the like. Due to the difference in rotational speed between the tool body 3 and the output shaft 10, the cam 33 makes one relative rotation. Due to the rotation of the cam 33, the center distance between the center of the cam follower 19 and the rotation center of the cam 33 changes (see FIG. 5), so that the drive slider 60 moves in the radial direction.

  As the cam 33 rotates, the cam follower 19 repeats the same movement. The amount of movement of the cam follower 19 in the radial direction is equal to the center distance between the center of the cam follower 19 and the rotation center of the cam 33. In other words, the amount of movement of the cam follower 19 in the radial direction is defined by the form of the cam groove 37 of the cam 33, and the driven slider 70 interlocked with the driving slider 60 has a predetermined amount of movement in an oblique direction with respect to the rotational axis of the main shaft 2a. Only to move.

  An output shaft 10 that is extrapolated to the shaft portion 7 of the tool main body 3 with a gap in a freely rotatable manner has a large diameter portion 11 and a small diameter portion 13 that follows the large diameter portion 11. A driving slider 60 and a driven slider 70 are provided on the large-diameter portion 11 on the distal end side. A center reamer 90 for finishing a small-diameter lower hole 82 formed in advance in the hole 81 of the workpiece 80 (see FIG. 6) is attached to the tip of the large-diameter portion 11. The center reamer 90 has a blade portion 91 and a shank portion 92, and the proximal end side of the shank portion 92 is detachably fixed to the large diameter portion 11 with a set screw that is screwed into the female screw 18. As shown in the schematic view of the valve seat portion of the workpiece 80, FIG. 6 shows a small-diameter valve guide hole (lower hole) by a throw-away type cutting insert 95 provided in the center reamer 90 and the driven slider 60. ) 82 and the taper hole inner peripheral surface 83 are coaxially machined with high accuracy. Thereby, the sealing performance between the valve and the taper hole inner peripheral surface 83 is improved.

  The drive slider 60 is inserted into the guide hole 14 of the large diameter portion 11 together with the guide block 61 (see FIG. 2). The drive slider 60 has a cam follower 19 that engages with the cam groove 37 on one side surface, and an engagement hole 62 on the other side surface. The drive slider 60 is guided by the guide block 61 and is perpendicular to the rotation axis, that is, a radius. Slide in the direction. The guide block 61 fixed to the guide hole 14 engages with a protrusion 60a protruding from the lower surface of the drive slider 60, and guides the drive slider 60 in a direction perpendicular to the rotation axis (first groove). The guide portion) 61a.

  As shown in FIG. 2, the driven slider 70 is mounted together with the guide plate 71 in the groove 17 (see FIG. 2) of the large diameter portion 11. The driven slider 70 includes a triangular cutting insert 95 on the front side, and has an engagement protrusion 72 that engages with the engagement hole 62 of the drive slider 60 on the rear side. The driven slider 70 is guided by the guide plate 71 and rotates. It slides in the direction inclined with respect to. The engagement hole 62 of the drive slider 60 and the engagement protrusion 72 of the driven slider 70 are engaged so as to be slidable in the axial direction of the main shaft. The guide plate 71 fixed to the groove 17 of the large-diameter portion 11 engages with a ridge 70a projecting from the lower surface of the driven slider 70 and is driven in a direction inclined with respect to the rotation axis. Guide groove (second guide part) 71a.

  FIG. 3 shows a state in which the driving slider 60 and the driven slider 70 are connected. When the driving slider 60 moves in the upward direction a, the driven slider 70 moves in conjunction with the direction aa in which the cutting edge of the cutting insert 95 approaches the rotation axis, and when the driving slider 60 moves in the downward direction b, the driven slider 70 is moved. The cutting edge of the cutting insert 95 moves in conjunction with a direction bb away from the rotation axis.

  An output gear 27 is integrally provided on the outer peripheral surface of the small diameter portion 13 on the proximal end side of the output shaft 10. A pair of oil seals 42 and 43 are in contact with the oil seal case 44 on the outer peripheral surface of the small diameter portion 13 adjacent to the output gear 27. Inside the output shaft 10, a small-diameter hole 15 and a large-diameter hole 16 into which the tip of the shaft portion 7 of the tool body 3 enters are formed. The small-diameter hole 15 on the distal end side has a communication hole communicating with the guide hole 14, and a cam groove formed in the head 35 of the cam 33 disposed in the small-diameter hole 15 through the communication hole. 37, the front end side of the cam follower 19 protruding from the side surface of the drive slider 60 is engaged.

  Further, the cutting tool 1 according to the present embodiment detects that the cutting edge position of the insert 95 provided on the tip end side of the driven slider 70 is at the origin, that is, that the rotational position of the cam 33 is at the origin. A positioning mechanism is provided. By detecting the origin of the cam 33 by the positioning mechanism, it is possible to prevent the cutting edge of the insert 95 from interfering with the workpiece when the cutting tool 1 is inserted into the hole 81 of the workpiece 80. The positioning mechanism includes a socket 51 fixed to the end surface of the spindle head 2, an anti-rotation pin 52 connected to the socket 51, one end connected to the anti-rotation pin 52, and the other end connected to the oil seal case 44. A tube 53 and a pressure sensor (not shown) for detecting the back pressure of the supplied air are provided. The socket 51, the rotation prevention pin 52, and the air tube 53 are formed with through holes 54 for flowing air. In addition, when the rotational position of the cam 33 is at the origin, the air supplied from the machine side passes through the socket 51, the detent pin 52, and the air tube 53 in the shaft portion 7 and the output shaft 10 of the tool body 3. A communication hole 56 is formed to pass through the hole 54, pass through the shaft portion 7 of the tool body 3 and the output shaft 10, and be discharged outside. Therefore, when the supplied air is discharged to the outside of the tool body 3 and the back pressure is reduced, it can be recognized that the cutting edge position is at the origin, and conversely, when the back pressure is detected, the cutting edge position is It can be recognized that it is not at the origin.

In the positioning mechanism of the present embodiment, when the cutting tool 1 is in an ATC magazine (not shown), the cam 33 always has an origin phase (predetermined angular position) that comes every predetermined number of rounds. To. The actual sequence including the positioning of the tool 1 by the positioning mechanism is as follows.
1. The tool 1 is mounted on the spindle head 2 by ATC (automatic tool changer).
2. The tool 1 is originated by the positioning mechanism, and the tip of the tool 1 (tip of the output shaft 10) is inserted into the hole 81 of the workpiece.
3. The spindle 2a of the machining center is rotated by a predetermined number of revolutions (r rounds) by a spindle circumference count function, for example, Cs axis control (spindle rotation feed control), and the inner peripheral surface of the tapered hole is machined.
4). The tool 1 is extracted from the hole 81.
5. When there is another place to be machined, the tool 1 is moved to another machining position, and the above sequences 2 to 4 are repeatedly performed.
6). Finish processing.
7). At this time, the main shaft 2a is accurately rotated by r × h (h is an integer) by Cs axis control.
8). Change the tool with ATC and return tool 1 into the tool magazine.
Note that the origin of the tool 1 in 2 is achieved by rotationally positioning the spindle by Cs axis control.

  As described above, according to the cutting tool of the present embodiment, a difference in rotational speed occurs between the tool body 3 and the output shaft 10 by the differential transmission mechanism, and a difference in rotational speed between the tool body 3 and the output shaft 10 occurs. As the cam follower 19 is moved by being guided by the cam groove 37, the drive slider 60 is guided by the guide block 6 and moved in the radial direction, and the driven slider 70 is guided by the guide plate 71. Moves in a direction inclined with respect to the rotation axis. Thereby, the taper hole inner peripheral surface 83 can be processed with a single point contact with a low cutting resistance by the cutting edge of the insert 95 provided in the driven slider 70. When the cutting tool 1 of the present embodiment is applied to the processing of a valve seat in a combustion chamber of an engine or compressor, a processed surface without chatter marks is obtained, and a valve (not shown) and an inner periphery of a tapered hole are obtained. The sealing property with the surface 83 is improved, which contributes to increasing the combustion efficiency of the combustion chamber.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. In the present embodiment, the slider is shown as a separated type in which the slider is separated into the driving slider 60 and the driven slider 70, but an integrated slider 75 may be used as shown in FIG. In this modification, the integrated slider 75 is guided by a guide groove 76 formed in the large-diameter portion 11 and moves in an oblique direction with respect to the rotation axis. In the present embodiment, the protrusions 60a and 70a are formed on the drive slider 60 and the driven slider 70, and the guide grooves 61a and 71a are formed on the guide block 61 and the guide plate 71. Further, a groove may be formed in the driven slider 70, and a protrusion may be formed in the guide block 61 and the guide plate 71. In the present embodiment, a center reamer 90 is mounted on the large-diameter portion 11 of the output shaft 10 and the driven slider 70 is provided with a throw-away type cutting insert 95. However, instead of the center reamer 90, a drill is used. It is also possible to attach, and it is also possible to provide a brazing type blade portion instead of the throw-away type cutting insert 95.

It is sectional drawing which shows embodiment of the cutting tool which concerns on this invention. It is a perspective view of the cutting tool shown in FIG. It is sectional drawing explaining a motion of a drive slider and a driven slider. It is sectional drawing which shows the modification of the cutting tool of this Embodiment with which the drive slider and the driven slider were integrated. It is a front view of the cam which has a cam groove. It is explanatory drawing which shows the state which is cutting the process site | part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting tool 2 Spindle head 2a Spindle 3 Tool main body 10 Output shaft 14 Guide hole 19 Cam follower 26 Input gear 27 Output gear 48 Transmission gear 33 Cam 37 Cam groove 60 Drive slider 61 Guide block 70 Driven slider 71 Guide plate

Claims (3)

In a cutting tool mounted on a spindle of a machine tool and incorporating a differential transmission mechanism and a cam,
An input shaft mounted on the main shaft, wherein the cam is provided coaxially with the input shaft, the input shaft having the cam having a cam groove formed on a front end surface;
An output shaft that rotates at a rotational speed different from that of the input shaft by the differential transmission mechanism, and an output shaft that is arranged coaxially with the input shaft;
A slider provided on the output shaft having a cutting edge, the cam follower engaging with the cam groove, and the cam follower being guided and moved by the cam groove to move the rotation axis of the main shaft; A slider that moves in a direction inclined with respect to
A guide portion for guiding the slider in a direction oblique to the axis of the main shaft;
A cutting tool comprising: The slider includes a driving slider that moves in a direction perpendicular to the rotation axis, and a driven slider that moves in a direction inclined with respect to the rotation axis by being engaged with the driving slider. 2. A first guide portion that guides the driving slider in a direction orthogonal to the rotation axis, and a second guide portion that guides the driven slider in a direction inclined with respect to the rotation axis. The cutting tool described in 1.   The cutting tool according to claim 1, further comprising: a mounting portion that mounts a hole processing tool for processing a hole in the direction of the rotation axis on the tip side of the output shaft.

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