JP2016129919A - Hob - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hob that can secure high-processing accuracy for gear cutting without requiring a lot of time and workload for focusing a phase of a gear cutting blade.SOLUTION: The hob is provided with the gear cutting blade 4C extending while forming a serration shape in an extending direction of an axis line O in an outer periphery of hob body 1 turned about the axis line O. The gear cutting blade 4C in a row only is provided in the outer periphery of hob body 1. A fitting seat 2 is formed so as to extend parallel to the axis line O in the outer periphery of hob body 1 and the gear cutting blade 4C in a row only may be formed into a piece of a blade 4 that is detachably attached to the fitting seat 2.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hob that is provided with a saw-tooth cutting blade on the outer peripheral portion of a hob body and performs gear cutting.

  As such a hob, in Patent Document 1, a plurality of grooves along the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface of a cylindrical hob body, and a plurality of chevron shapes are formed on a supporter inserted into these grooves. An assembly-type hob in which a blade of this type is fitted and fixed has been proposed. Here, the supporter is positioned in the axial direction by the adjusting screw and the holding piece.

Japanese Utility Model Publication No. 63-091321

  By the way, in a hob in which a plurality of grooves are formed in the outer periphery of the hob body at intervals in the circumferential direction and the supporter and the blade are attached to these grooves, the angle of the angle formed by these blades is the axis. By sequentially shifting the position of the adjusting screw and holding piece of each groove so that a constant lead around, the supporter and the blade are also arranged so as to be spiral in the circumferential direction. Yes.

  However, it is difficult to position the blades attached to the plurality of grooves so that each of the chevron forms a spiral of the lead that is exactly constant. It takes a lot of time and labor to position the blade. In addition, if one of these blades has a chevron-shaped phase shift, the accuracy of the gear that has been gear cut will also be impaired. This is not limited to the assembly-type hob described in Patent Document 1, and the same applies to a solid or brazed hob.

  The present invention has been made under such a background, and provides a hob capable of ensuring high gear cutting processing accuracy without requiring much time and labor for phase alignment of the tooth cutting blade or the like. The purpose is that.

  In order to solve the above-described problems and achieve such an object, the present invention provides a gear cutting that extends in a sawtooth shape toward the direction in which the axis extends in the outer periphery of the hob body that is rotated around the axis. A hob provided with a blade, wherein only one row of the tooth cutting blades is provided on an outer peripheral portion of the hob main body.

  That is, in such a hob, only a single-toothed tooth cutting blade is provided on the outer periphery of the hob body, so that even the pitch of the saw blade formed by this one row of cutting blades is accurately formed. Then, the tooth profile can be formed on the workpiece by this one row of cutting blades without matching the phase with other cutting blades. For this reason, time and labor are not required for phase alignment, and further, the processing accuracy is not lowered due to the phase shift.

  Here, such a configuration can be applied to the above-described solid or brazed hob, but a mounting seat extending in parallel to the axis is formed on the outer peripheral portion of the hob body, and the one row is formed. If this tooth cutting blade is applied to an assembly-type hob formed on a single blade that is detachably mounted on the mounting seat, the positioning of the blade can be greatly simplified, so it is particularly effective. It is.

  Further, in this case, a plurality of recesses are formed in the outer peripheral portion of the hob main body adjacent to the mounting seat in the circumferential direction, and the blades are arranged in the axial direction to be mounted in the recesses. By pressing and attaching with the wedge member, a large contact area between the wedge member and the blade can be secured, and the blade can be pressed at a plurality of locations in the axial direction in which the blade extends. The blade can be stably attached to the hob body. Accordingly, it is possible to prevent the blade from rattling during gear cutting and to obtain high processing accuracy.

  Furthermore, by forming the wedge member in a plate shape or a column shape extending in the axial direction, it is possible to secure a larger contact area with the blade and further improve the mounting stability. Further, the pressed surface of the blade pressed by the wedge member is formed in a concave shape that is recessed in the thickness direction of the blade as it goes toward the outer peripheral side of the hob main body. It can be prevented from coming off.

  As described above, according to the present invention, since there is only one row of cutting blades extending in the direction in which the axis of the hob body extends, time and labor required for phase alignment among the plurality of rows of cutting blades can be saved. In addition, it is possible to prevent a reduction in gear cutting accuracy due to a phase shift and to manufacture a highly accurate gear.

It is the partially broken front view seen from the axial direction one end side (left side in FIG. 3) which shows one Embodiment of this invention. It is the rear view which looked at embodiment shown in FIG. 1 from the axial direction other end side (right side in FIG. 3). It is a sectional side view of the embodiment shown in FIG. It is a fragmentary top view of the arrow line X direction view in FIG. It is an expanded sectional view of the mounting seat periphery of the embodiment shown in FIG.

  1 to 5 show an embodiment of the present invention. In the present embodiment, the hob main body 1 is formed of a steel material or the like, and has a multi-stage outer shape centering on the axis O in which both end portions 1A in the direction of the axis O are equal in outer diameter and smaller in diameter than the body portion 1B therebetween. It has a cylindrical shape, and a rotation shaft of a hobbing machine is attached to the inner periphery of the cylinder, and gear cutting is performed while being rotated in the rotation direction T around the axis O.

  On the outer peripheral surface of the body portion 1B having a larger diameter than the both end portions 1A of the hob body 1, a recessed groove-shaped mounting seat 2 that extends from the outer peripheral surface to the inner peripheral side and extends parallel to the axis O is provided in the direction of the axis O. Only one strip is formed over the entire length, and is open to both end faces 1C of the body 1B. The mounting seat 2 includes a bottom surface 2A facing the outer peripheral side of the hob body 1 and a wall surface 2B facing the rotation direction T perpendicular to the bottom surface 2A, and a corner angle at which the bottom surface 2A and the wall surface 2B intersect. An escape portion 2 </ b> C that is recessed in a “U” shape is formed in the portion.

  In addition, a recess 3 that is adjacent to the circumferential direction of the mounting seat 2 and communicates with the mounting seat 2 is formed in the outer peripheral portion of the body portion 1B. In this embodiment, the recess 3 is formed adjacent to the rotation direction T side of the mounting seat 2, and the bottom surface 3 </ b> A is located slightly on the inner peripheral side of the hob body 1 with respect to the bottom surface 2 </ b> A of the mounting seat 2. The bottom surface 3A has a wall surface 3B which is located on the rotation direction T side and extends toward the outer peripheral side, and faces the rear side in the rotation direction T. The wall portion 1B extends in parallel to the axis O like the mounting seat 2. Only one strip is formed over the entire length in the direction of the axis O so as to open at both end faces 1C of. Further, a plurality of screw holes 3C having a center line extending in parallel with the wall surface 3B on a plane perpendicular to the axis O are formed on the bottom surface 3A of the recess 3 at equal intervals in the direction of the axis O (3 in this embodiment). Are formed one by one.

  Furthermore, on the outer peripheral surface of the body portion 1B, an inclined surface 1D is formed from the outer peripheral edge of the wall surface 3B of the recess 3 toward the rotational direction T toward the outer peripheral side of the hob body 1 toward the rotational direction T. Has been. The inclined surface 1D is cut off to the outer peripheral surface of the body 1B just before reaching the wall surface 2B of the mounting seat 2 adjacent to the rotation direction T side of the recess 3 to form the bottom surface of the chip pocket. A key groove 1E that fits with a key provided on the rotation shaft of the hobbing machine is formed on the inner peripheral portion of the hob main body 1 on the opposite side of the mounting seat 2 with the axis O interposed therebetween.

  A blade 4 is detachably attached to the mounting seat 2. Therefore, the hob of this embodiment is an assembly-type hob, and there is only one blade 4 attached to one hob body 1. The blade 4 is formed in a flat plate shape from a hard material such as cemented carbide, and the seating surface 4A is directed toward the inner peripheral side of the hob body 1 with the thickness direction of the flat plate directed in the circumferential direction of the hob body 1. Is brought into close contact with the bottom surface 2A of the mounting seat 2 and the back surface 4B directed toward the rear side in the rotation direction T is brought into close contact with the wall surface 2B so as to be seated on the mounting seat 2. In the present embodiment, a blade 4 having a length substantially equal to the length of the body 1 </ b> B of the hob body 1 in the axis O direction is attached to the mounting seat 2.

  The width of the blade 4 seated on the mounting seat 2 in the radial direction of the hob body 1 is made larger than the depth of the mounting seat 2 from the outer peripheral surface of the body 1B of the hob body 1 to the bottom surface 2A. Therefore, the blade 4 protrudes from the outer peripheral surface of the body portion 1B, and the protruding portion has a sawtooth shape uneven in the radial direction of the hob body 1 as shown in FIG. A tooth cutting edge 4 </ b> C is formed which extends in the shape and forms a tooth profile on the workpiece. Therefore, the tooth cutting blade 4C provided in one hob main body 1 is also only one row. In the present embodiment, the size and pitch of the individual saw teeth formed by the tooth cutting blade 4C in the blade 4 are constant.

  Moreover, the surface which continues to the rotation direction T back side of the tooth cutting blade 4C and is directed to the outer peripheral side of the hob main body 1 of the blade 4 is a flank 4D. A clearance angle is given to the flank 4D from the tooth cutting edge 4C toward the rear side in the rotation direction T toward the inner peripheral side of the hob body 1, and an axis O direction as it goes toward the rear side in the rotation direction T. Leads are provided so as to be twisted from one end to the other end (from the left end to the right end in FIGS. 3 and 4).

  On the other hand, a surface that is connected to the tooth cutting blade 4C and is directed to the rotation direction T on the outer peripheral side of the hob body 1 of the blade 4 is a rake surface 4E. It is formed so as to be positioned on a plane including O. The seating surface 4A of the blade 4 is formed perpendicular to the back surface 4B.

  Further, a pressed surface 4F is formed on a portion of the surface facing in the rotation direction T as in the rake surface 4E of the blade 4 that is located on the inner peripheral side of the hob body 1 and faces the recess 3. The pressed surface 4F is concavely inclined toward the back surface 4B side by being gradually recessed in the thickness direction of the blade 4 with respect to the rake surface 4E as it goes toward the outer peripheral side (rake surface 4E side) of the hob body 1. It is formed in a plane and is connected to the rake face 4E through a small step slightly recessed on the back face 4B side. Such a pressed surface 4F is formed over the entire length of the blade 4 with a certain width from the seating surface 4A, and in the state where the blade 4 is seated on the mounting seat 2 as described above, this pressed surface 4F inclines so that it may space apart with respect to the said wall surface 3B of the recess 3 as it goes to the outer peripheral side of the hob main body 1. FIG.

  Such a blade 4 seated on the mounting seat 2 is mounted by pressing the pressed surface 4F by a wedge member 6 mounted in the recess 3 by a clamp screw 5. The clamp screw 5 is formed with male screw portions 5A and 5B twisted in opposite directions at both ends, and the male screw portion 5A formed at one end of the clamp screw 5 is a screw hole in the recess 3. Screwed into 3C.

  The wedge member 6 has a planar side surface 6A that is directed in the rotational direction T and is in sliding contact with the wall surface 3B of the recess 3, and a pressing surface 4F that is directed to the rear side in the rotational direction T and presses the pressed surface 4F. The pressing surface 6B is provided, and is formed in a plate shape or a column shape extending in the axis O direction. The pressing surface 6B is inclined so as to be separated from the side surface 6A toward the outer peripheral side of the hob body 1, and the wedge member 6 has a trapezoidal cross section, and the pressing surface 6B forms the side surface 6A. The inclination angle is substantially equal to the inclination angle formed by the pressed surface 4F of the blade 4 seated on the mounting seat 2 with respect to the wall surface 3B of the recess 3.

  Further, the wedge member 6 is formed with a screw hole 6C between the side surface 6A and the pressing surface 6B into which the male screw portion 5B formed at the other end of the clamp screw 5 is screwed. The screw hole 6C is formed to be coaxial with the screw hole 3C of the recess 3 when viewed from the direction of the axis O when the side surface 6A is brought into close contact with the wall surface 3B of the recess 3.

  Furthermore, in the present embodiment, a plurality of (three) wedge members 6 having the same number as the screw holes 3C formed in one recess 3 are axially connected by one clamp screw 5 that is screwed into the screw hole 3C. It is mounted in the recess 3 so as to line up in the O direction. That is, the single blade 4 seated on the mounting seat 2 is mounted by the plurality of wedge members 6.

  The plurality of wedge members 6 mounted in the recess 3 are of the same shape and size, and the length of each wedge member 6 in the direction of the axis O is the length of the recess 3 in the direction of the axis O. The length of the wedge member 6 is slightly shorter than the length divided by the number of wedge members 6, and one screw hole 6 C is formed in each wedge member 6 in the central portion in the axis O direction of each wedge member 6. Thereby, a slight gap is formed between the wedge members 6 adjacent to each other in the direction of the axis O attached to the recess 3.

  By mounting the wedge member 6 in the recess 3 with the clamp screw 5, the blade 4 seated on the mounting seat 2 is pressed against the pressed surface 4 </ b> F and the seating surface 4 </ b> A and the back surface 4 </ b> B are mounted on the mounting seat 2. Are pressed against the bottom surface 2A and the wall surface 2B, respectively, and fixed to the mounting seat 2. In this embodiment, as shown in FIGS. 2 and 3, an annular plate-like plate 7 having an outer diameter substantially equal to that of the body 1B is inserted from the other end 1A of the hob body 1, The blade 4 is screwed to the other end surface 1C of the body portion 1B, and the blade 4 is positioned in the axis O direction with the end surface facing the other end side in the axis O direction contacting the plate 7.

  In the hob configured as described above, only one row of the tooth cutting blades 4C for forming a tooth profile on the work is provided on the outer peripheral portion of the hob body 1, so that the gears of other rows are provided. There is no need to perform phase alignment with the blade, and gear cutting can be performed by controlling the hobbing machine with simple positioning such that the end surface of the blade 4 contacts the plate 7 as described above. For this reason, it is possible to reduce the time and labor required for phase alignment between multiple rows of tooth cutting blades, which is efficient, and it is possible to prevent a decrease in machining accuracy due to a phase shift. Precision gear cutting can be performed.

  Further, in the present embodiment, only one blade 4 on which one row of cutting blades 4C as described above is formed is detachably attached to the mounting seat 2 formed on the hob body 1 alone. The above configuration is applied to the assembly type hob. For this reason, when the tooth cutting edge 4C is worn or damaged, the blade 4 may be replaced, and positioning of the new blade 4 at that time can be performed by the simple operation as described above. And even with such an assembly-type hob, since the positioning of the blade 4 is easy, there is no need for an adjustment mechanism such as the adjustment screw of the hob described in Patent Document 1, Simplification can be achieved.

  However, in addition to such an assembly-type hob, for example, a solid hob formed integrally with the outer peripheral part of the hob body formed of high-speed tool steel, etc. In a brazed hob in which a blade made of cemented carbide or the like with a blade formed thereon is brazed, only one row of cutting blades may be formed. In the present embodiment, the rotating shaft of the hobbing machine is attached to the inner peripheral portion of the cylindrical hob body 1. For example, a handle (shank) extending along the central axis O is provided on the hob body. It is also possible to apply the present invention to a hob with a handle that is formed, and this handle is attached to a spindle of a machine tool and rotated to perform gear cutting.

  On the other hand, in the present embodiment, in the assembly-type hob as described above, a plurality of blades 4 seated on the mounting seat 2 are arranged in the direction of the central axis O of the hob body 1 (3 in the present embodiment). Since the wedge member 6 is pressed and attached, a large contact area between the pressed surface 4F of one blade 4 and the pressed surface 6B of these wedge members 6 can be secured. A plate-like blade 4 extending in the direction of the axis O can be attached by pressing at a plurality of locations in the same direction of the center axis O. For this reason, it becomes possible to attach the blade 4 to the hob main body 1 stably, it is possible to prevent the blade 4 from rattling during gear cutting, and high processing accuracy can be obtained. .

  Further, in this embodiment, each of the plurality of wedge members 6 that press the single blade 4 is formed in a plate shape or a column shape extending in the direction of the central axis O, and the blade 4 extends substantially over its entire length. It is pressed by the plurality of wedge members 6. For this reason, a larger contact area between the blade 4 and the wedge member 6 can be ensured, and the blade 4 can be stably attached to the hob body 1 to improve the processing accuracy.

  Further, the pressed surface 4F of the blade 4 is formed in a concave shape that is recessed in the thickness direction of the blade 4 directed in the circumferential direction toward the outer peripheral side of the hob body 1, and this pressed surface 4F is formed into a wedge member. When the pressing surface 6B of 6 is in close contact and pressed, the blade 4 can be attached to the outer peripheral side of the hob body 1 while being prevented from coming off. For this reason, even when the hob body 1 is rotated at a high speed during gear cutting, the blade 4 can be prevented from rattling, and the blade 4 can be held more stably and the high efficiency gear cutting. Processing can be performed.

  In the present embodiment, there is only one row of tooth cutting blades 4C for forming (creating) a tooth profile on the workpiece. For example, there is a chamfering blade for chamfering the protrusion in the tooth height direction of the tooth shape formed by the tooth cutting blade 4C. It may be provided at a position different from the tooth cutting edge 4C. In the present embodiment, the pitch of the saw blades formed by the tooth cutting blades 4C in each blade 4 is constant. For example, a blade having a chipped cutting blade lacking teeth at a predetermined position may be used.

  Further, in order to balance the rotation of the hob, for example, a balance blade that does not perform gear cutting on the opposite side of the tooth cutting blade 4C across the axis O may be provided. The hob of the above embodiment may be configured by attaching the blade 4 to only one mounting seat 2 of the hob main body 1 having the mounting seat 2 (groove). Furthermore, the row of cutting blades 4C only needs to extend in the direction in which the axis O of the hob body 1 extends, and may be twisted around the axis O, for example.

DESCRIPTION OF SYMBOLS 1 Hob main body 2 Mounting seat 3 Recess 4 Blade 4C Tooth cutting blade 4F Pressed surface 5 Clamp screw 6 Wedge member 6B Press surface O Hob main body 1 axis T Rotation direction

Claims (5)

  A hob provided with tooth cutting blades extending in a sawtooth shape in the direction in which the axis extends in the outer periphery of the hob body rotated around the axis, and only one row is provided on the outer periphery of the hob body. A hob comprising the above-described tooth cutting blade.   A mounting seat extending in parallel with the axis is formed on the outer peripheral portion of the hob body, and the tooth cutting blades of only one row are formed on a single blade that is detachably mounted on the mounting seat. The hob according to claim 1, wherein:   A recess is formed in the outer peripheral portion of the hob main body adjacent to the circumferential direction of the mounting seat, and the blade is pressed by a plurality of wedge members arranged in the axial direction mounted in the recess. The hob according to claim 2, wherein the hob is attached.   The hob according to claim 3, wherein the wedge member is formed in a plate shape or a column shape extending in the axial direction.   The pressed surface of the blade pressed by the wedge member is formed in a concave shape that is recessed in the thickness direction of the blade as it goes toward the outer peripheral side of the hob body. 4. The hob according to 4.

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