Bevel gear cutting tool with non-rectangular quadrilateral bit slots and cutting blades

Abstract

The cutting head (50) has a plurality of cutting blade receiving slots (51), at least one of which has a cross-section in the form of a non-rectangular quadrilateral. Furthermore, the cross-section of the cutting blade (52) is a non-rectangular quadrilateral, in which the cross-sectional shape of the cutting blade is complementary to the cross-sectional shape of the non-rectangular quadrilateral cutting blade receiving slot (51), such that the cutting blade can be positioned and clamped in the cutting blade receiving slot.

Description

Technical Field

[0001] The present invention relates to the manufacture of gears, and in particular to cutting tools for the manufacture of gears such as bevel gears and hypoid gears. Background Art

[0002] Bevel gears and hypoid gears can be cut in a single indexing process or an intermittent indexing process (face milling) or in a continuous indexing process (face hobbing) by either a generating method or a non-generating method. The basic cutting device in the generating plane or the support plane will place the center of the cutter head in a position away from the center of the generated gear (support axis) by a distance amount called the radial distance. When the cutter rotates, the profile of the cutter blade represents one tooth of the generated gear. Common face tools for bevel gear cutting have several blade groups, wherein each blade group has between one and four cutting blades, which are usually called "stick" blades or "bar" blades. The most common is an alternating (complete) tool with one external cutting blade and one internal cutting blade. In order to achieve equal cutting loads for all internal blades and all external blades in the cutting process, the goal is to have the cutting edges of all external blades and all internal blades follow each other at the same radial position.

[0003] In the case of the most common stick blade tool, the cutter head 10 ( Figure 1 ) is a disc with slots and a clamping device for a blade bar. The cutter head blade receiving slot can have different cross-sections, such as square, rectangular, pentagonal or circular as known in the art. Blade bars designed for different slots usually have corresponding complementary blade receiving slot cross-sections. The bar blade size is defined by an amount slightly smaller than the cutter head receiving slot, which allows the blade to be inserted into the slot and positioned in the slot.

[0004] Common rectangular blade systems hold the blade in place against the cutting forces by friction. Blades with a pentagonal cross section are held in place against the cutting forces by positive seating. In the case of a circular blade cross section, the blade may be held by friction or by positive seating, depending on the clamping principle. Summary of the invention

[0005] The present invention relates to a cutter head having a plurality of cutting blade receiving slots, wherein at least one cutting blade receiving slot has a non-rectangular quadrilateral cross section.

[0006] Another embodiment of the present invention includes a cutting blade having a non-rectangular quadrilateral cross-section, wherein the cross-sectional shape of the cutting blade is complementary to the cross-sectional shape of the non-rectangular quadrilateral cutting blade receiving slot, so that the cutting blade can be positioned and clamped in the cutting blade receiving slot.

[0007] In a preferred embodiment, the cutter head includes a plurality of cutting blade receiving slots, wherein, relative to the direction in which the cutter head rotates about its rotational axis during the cutting process, at least one blade receiving slot includes a leading side surface having a slot depth of W2 and a trailing side surface having a slot depth of W1 (the trailing side surface being a seating surface), wherein W2 is less than (<) W1. The blade receiving slot also includes an inner side angle surface extending between the leading side surface and the trailing side surface and an outer side surface, the inner side angle surface also being a seating surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Shown is a three-dimensional view of a face milling cutter head having rectangular insert pockets.

[0009] Figure 2 A cutter head portion having a rectangular slot cross section and a rectangular blade cross section is shown. The clamping force uses friction to hold the blade against the cutting force F. C Keep it in its position.

[0010] Figure 3 A cutter head section 30 with a pentagonal slot cross section and a pentagonal insert cross section is shown. The clamping force presses the insert via contact surface 37 into the prismatic seat consisting of contact surface 35 and contact surface 36, thereby achieving a positive (form) seat.

[0011] Figure 4 A segment of a cutter head with a slot having a circular (circle) cross section and with a blade having a circular (circle) cross section is shown, wherein the circular shape is interrupted by a flat section. The diameter of the slot is larger than the diameter of the blade. Figure 4 The arrangement in provides a friction seat.

[0012] Figure 5 A tool tip section is shown in which the slot cross section is a quadrilateral that is non-rectangular.

[0013] Figure 6 A tool tip section is shown having a non-rectangular quadrilateral slot cross section including a machined groove or check.

[0014] Figure 7 A cutter head section is shown in which the slot cross-section is a non-rectangular quadrilateral and the cutting blade cross-section is a non-rectangular quadrilateral.

[0015] Figure 8 A cutter head section is shown having a slot cross section that is a non-rectangular quadrilateral and a cutting blade cross section that is a non-rectangular quadrilateral with radial spacers.

[0016] Fig. 9 is an isometric view of a non-rectangular quadrilateral cutting blade showing the back contact side and the inner corner contact side.

[0017] Fig.10 Shows Fig. 9 An opposite side view of a cutting blade of , showing the front side and the outer side as well as the cutting edge, the clearance edge and the front end face.

[0018] Fig.11 A partial view of a tool head with a cutting blade positioned in each of two blade receiving slots is shown.

[0019] Fig.12 A cutter head section is shown having a slot cross section that is a non-rectangular quadrilateral and a cutting blade cross section that is a pentagonal with radial spacing blocks. DETAILED DESCRIPTION

[0020] The terms "invention," "described invention," and "present invention" as used in this specification are intended to refer broadly to all subject matter of this specification and any patent claims that follow. Statements containing these terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of any patent claim attached. In addition, this specification does not seek to describe or limit the subject matter covered by any claim in any particular part, paragraph, statement, or figure of this application. The subject matter should be understood by reference to the entire specification, all drawings, and any claims attached. The present invention can use other configurations and can be practiced or implemented in various ways. Furthermore, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered limiting.

[0021] The use of "including," "having," and "comprising," and variations thereof, herein is intended to encompass the items listed thereafter and their equivalents as well as additional items. The use of letters to identify elements of a method or process is for identification purposes only and is not meant to indicate that the elements should be performed in a particular order. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and the term "and / or" includes any and all combinations of one or more of the listed associated items.

[0022] Although reference may be made below to directions such as upper, lower, upward, downward, rearward, bottom, top, front, rear, etc., when describing the drawings, for convenience, these references are made relative to the drawings (as normally viewed). These directions are not intended to be taken literally or to limit the present invention in any way. In addition, unless expressly stated, terms such as "first", "second", "third", etc. are used herein for descriptive purposes and are not intended to indicate or imply importance or significance.

[0023] The details of the present invention will now be discussed with reference to the accompanying drawings, which illustrate the present invention by way of example only. In the accompanying drawings, similar features or components will be referred to by similar reference numerals. For the purpose of clarity or detailed explanation, the size and relative size of some aspects or elements may be exaggerated.

[0024] In the context of the present invention, the term "bevel" gear is understood to be broad enough to include those types of gears known as bevel gears, "hypoid" gears, and those gears known as "crown" gears or "face" gears.

[0025] Figure 1 A three-dimensional view of a known face milling cutter head 10 is shown with a rectangular outer insert slot 15 and a rectangular inner insert slot 16. The slots 15 and 16 represent one blade set 11. The cutter head 10 rotates in a direction 14 during cutting.

[0026] Figure 2 A section 20 of a known cutter head with a rectangular slot 21 and a rectangular blade 22 is shown. A clamping screw 23 is in contact with a clamping block 24, which enables surfaces 25 and 26 to generate a cutting force F C The friction force F is equal in magnitude but opposite in direction F1 and F F2 (F C =-F F1 -F F2 ).

[0027] Figure 3 A cutter head section 30 is shown with a pentagonal (pentagonal shape) slot 31 and a pentagonal blade 32 (see, for example, US 6,120,217). A clamping screw 33 contacts a clamping block 34 and presses the blade 32 through a surface 37 into two prismatic seating surfaces 35 and 36. Upon application of a cutting force F C In the case of R1 and F R2 The cutting force F C Tight, positive blade seating will allow the reaction force to be adjusted (theoretically) to any cutting force because it is independent of any surface friction.

[0028] Figure 4 A section 40 of a known cutter head with a circular slot 41 and a circular blade 42 with a flat section 47 is shown. The diameter of the blade 42 must be smaller than the diameter of the cutter slot 41 in order to provide a clearance fit between the slot and the blade for forceless insertion of the blade. The clamping screw 43 contacts the blade surface 47 and presses the blade 42 against the point 45. Due to the difference in curvature, the point 45 will expand to the contact surface area. In the presence of a cutting force F CIn the case of F1 (friction force on surface 47) and F F2 The friction force (at point 45) will act on the cutting force with the same magnitude but in the opposite direction. In the case of high cutting forces, the friction force F F1 +F F2 May be less than the cutting force F C size, which will cause the blade to slip. Figure 4 Another disadvantage of the arrangement in can be seen in that the clamping screw 43 contacting the blade flat portion 47 provides as the only geometric feature a defined rotational seating orientation 56 which is not sufficient for a cutting blade.

[0029] Figure 5 A section of a cutter head 50 of the present invention is shown (seen in an axial cross-section defined by a plane perpendicular to the axis of rotation of the cutter head 50) including a cutting blade receiving slot 51 in the form of a non-rectangular (i.e., not rectangular) quadrilateral having side 55, side 56, side 57, and side 58. For purposes of discussion and illustration, the cutting blade receiving slot 51 (in all figures) is parallel to the axis of rotation of the cutter head 50 on the top surface ( Fig.11 106) and a bottom surface (not shown). Side 55 and side 56 are mounting or seating surfaces against which the cutting blade will contact and seat when positioned and clamped in slot 51. Side 55 is the tail or back seating surface with reference to the direction "R" of rotation of the cutter head during machining, and is preferably parallel to the front side 57. The distance between side 55 and side 57 is referred to as the width of the tooth slot. Side 56 is an angular seating surface extending between and intersecting the front or front side 57 (defined relative to direction R) and the tail side 55.

[0030] The intersection angle α1 between the side 57 and the side 56 is greater than ninety degrees (i.e., >90°) and the intersection angle α2 between the side 55 and the side 56 is less than ninety degrees (i.e., <90°). The side 58 is the outer side of the slot 51 and includes at least one opening, preferably a threaded opening, wherein a clamping screw (e.g., Figure 7 53) or other clamping mechanism can extend through the threaded opening. The outer side 58 is preferably perpendicular to the side 55 and the side 57. The angle side 56 can be considered to be relative to the rotation axis of the cutter head 50 (see Fig.11 ) because corner side 56 is closer (radially) to the axis of rotation than side 58. Thus, side 58 is the "outer" side of slot 51 relative to the same axis of rotation. The slot depth of side 55 is W1, and the slot depth of side 57 is W2, which is less than W1 (i.e., W2 <W1)。

[0031] Figure 6 and Figure 5 Same except for the inclusion of a groove 59 referred to as a "check" which is used to act as a machining clearance when finish machining the clamping surface 55 and the seating surface 56 because many tools cannot adequately and repeatedly machine sharp corners, and furthermore, sharp corners may cause stress concentrations.

[0032] Figure 7 Shows Figure 5 The cutter head 50 of the present invention includes a rod-type or strip-type cutting blade 52 installed in a narrow slot 51 (shown in a cross-section defined by a plane perpendicular to the rotation axis of the cutter head 50), wherein the cutting blade 52 includes four non-rectangular (i.e., not rectangular) sides and is defined by an outer side 60, a front side or positive side 61, a tail contact side or back contact side 62, and an inner corner contact side 64. The distance between the side 61 and the side 62 is referred to as the width of the cutting blade, and the distance between the side 60 and the contact side 64 is referred to as the thickness of the cutting blade. The terms "front" and "tail" are defined according to the working orientation of the cutting blade 52 as installed in the narrow slot 51 during machining. The cutting edge, not shown, is located on the positive side 61 of the blade 52 at the end of the portion of the blade extending from the positive end face of the cutter head 50. For the purpose of discussion and illustration, the cutting blade 52 extends parallel to the rotation axis of the cutter head 50.

[0033] The clamping force F of the clamping screw 53 and the clamping block 54 夹持 The clamping force F is transmitted to the blade 52 by contacting the surface of the blade outer side 60. In order to achieve a balance between the clamping force and the surfaces of the contacting sides 62 and 64 of the blade, the clamping force F 夹持 is divided into the normal force F N1 and F N2 . Normal force F N1 The blade is pressed against the slot seating surface 55, and the normal force F N2 Press the blade onto the slot seating surface 56. R1 Yes F N1 The reaction force, and F R2 Yes F N2 The clamping force holds the blade tightly and rigidly in the correct position. C There will only be a reaction force F on surface 55 R3 The surface 55 is perpendicular to the average cutting force F C , which generates a reaction force F of equal magnitude but opposite direction to the cutting force R3This condition is optimal for accurate and rigid blade seating in the cutter head. Due to the clamping and cutting forces, a small spacing 70 will exist between the front side 61 of the cutting blade 52 and the front side 57 of the slot 51. If desired, the blade corner formed by the intersection of the side 55 and the side 56 can be slightly rounded to eliminate sharp corners.

[0034] The non-rectangular quadrilateral blade slot 51 and the cutting blade design make one seating surface 55 of the slot 51 perpendicular to the average cutting force F C The second seating surface 56 is oriented at an angle ( Figure 5 ) and therefore at a clamping force F 夹持 The sliding of the cutting blade 52 against the seating surface 55 is achieved during the clamping of the blade. Compared to the prior art, the arrangement between the cutting blade and the cutter head mounting slot of the present invention enables the clamping force to press the blade firmly against the seating surface, while one of the seating surfaces is perpendicular to the average cutting force. Compared to the prior art solutions, during the cutting process, Figure 7 The arrangement shown exhibits a significant static and dynamic increase in seating stiffness and seating accuracy. Increased cutting force F C The contact pressure on the seating surface 55 will be increased by the same factor.

[0035] Figure 8 The slot cross section 51 is shown to be a non-rectangular quadrilateral and as shown in FIG. Figure 7 The cutting blade 52 shown in cross section is a section of a cutter head 50 in a non-rectangular quadrilateral shape. In order to achieve different radial positions of the blade (relative to the axis of rotation of the cutter head 50), a radial shim spacer block 67 is used to increase the radial blade position (i.e., the distance of the blade 52 from the axis of rotation of the cutter head 50) by an amount 63. The spacer block 67 is shaped to closely contact the slot seating surfaces 55 and 56 at the corresponding contact surfaces 65 and 66 and the blade contact surface 64 via the spacer block seating surface 69. The connecting screw 68 connects the spacer block 67 to the body of the cutter head 50.

[0036] The radial blade shimming achieved with the spacer block 67 enables the same cutter head to be used to cut a wider range of different gear geometries. It is highly desirable to achieve this flexibility in order to reduce cutter head inventory, which has heretofore only been achieved by placing conventional parallel spacers between the slot surfaces 25 holding the friction blade and the cutting blade 22 (see Figure 2) between the slots 55 and 56 of the cutter head body 50 and towards the blade surface 64. The spacer block 67 increases the radial position of the blade 52 by an amount 63. The amount 63 may vary within the various available spacer blocks to increase flexibility in using different blade sizes and covering a wider range of gear geometries.

[0037] Shown in cross section Figure 7 and Figure 8 The cutting blade 52 is shown in an isometric view in FIG. Fig. 9 and Fig.10 middle. Fig. 9 A cutting blade 52 having a non-rectangular cross-section and a quadrilateral shape is shown, the cutting blade having an overall length between the tip and the bottom end of the cutting blade, as shown in FIG. Fig. 9 The cutting blade 52 includes an outer side 60, a front side or front side 61, a rear contact side or back contact side 62 and an inner corner contact side 64. Figure 7 The terms "front" and "rear" are defined by the working orientation of the cutting blade 52 in the cutting blade 51 during machining. The thickness of the cutting blade 52 at the back contact side 62 is greater than the thickness at the front side 61. The cutting edge 90 is located at the blade 52 from the blade head (e.g., Fig.11 The cutting blade 52 also includes a shoulder 91, a cutting side profile surface 92 and a tip finishing surface 98. A rectangular reference cross section is shown at 100.

[0038] Fig.10 Shows Fig. 9 9, wherein the positive end face 94, the clearance edge 95, the clearance side profile surface 96 and the shoulder 93 are visible. The positive end face 94 is shown as being oriented at a certain cutting angle (rake angle) K, which is shown as a cutting angle that exemplifies a positive value, but can also be zero or negative.

[0039] Fig.11 A partial view of a cutter head 50 rotatable in a clockwise direction R about a tool axis T is shown. The cutter head 50 includes a plurality of cutting blade receiving slots 51. An inner cutting blade 102 and an outer cutting blade 104 are shown positioned in respective receiving slots of the cutter head and extending from an end face 106 of the cutter head 50.

[0040] Fig.12A section of a cutter head 50 is shown in which the slot cross-section 51 is a non-rectangular quadrilateral and has a pentagonal blade 72 shown in cross-section. The cutting edge, not shown, is located on the positive side of the blade 72 at the end of the portion of the blade that protrudes from the positive end face of the cutter head 50 (i.e., on the side adjacent to the spacing 70). In order to achieve different radial positions of the blade (relative to the rotation axis of the cutter head 50), a radial shim spacer block 77 is used to increase the radial blade position (i.e., the distance of the blade 72 from the rotation axis of the cutter head 50) by an amount 73. The spacer block 77 is shaped to closely contact the slot seating surfaces 55 and 56 via corresponding contact surfaces 81 and 82 and to closely contact the contact surfaces 74 and 79 of the cutting blade 72 via corresponding spacer block seating surfaces 83 and 84. A connecting screw 78 connects the spacer block 77 to the body of the cutter head 50. Due to the clamping and cutting forces, there will be small spacings 70 , 71 between the front side of the cutting blade 52 and the front side 57 of the slot 51 , and between the back side of the cutting blade 52 and the trailing side 55 of the slot 51 .

[0041] The spacer block 77 is shaped to accommodate the seating of the slot surfaces 55 and 56 toward the cutter head body 50 and toward the cutting blade 72 having the contact surfaces 74 and 79. The spacer block 77 increases the radial position of the blade 52 by an amount 73. The amount 73 may vary within the various available spacer blocks to increase flexibility in using different blade sizes and covering a wider range of gear geometries.

[0042] Although the present invention has been described with reference to the preferred embodiment, it should be understood that the invention is not limited to the details thereof. The present invention is intended to include modifications obvious to those skilled in the art without departing from the spirit and scope of the appended claims.

Claims

1. A gear cutting tool having a rotation axis and comprising a cutter head, wherein: The cutter head includes a plurality of cutting blade receiving slots, wherein, relative to the direction in which the cutter head rotates around the rotation axis during the gear cutting process, an axial cross-section of at least one of the receiving slots is a non-rectangular quadrilateral and the at least one receiving slot includes a leading side surface with a slot depth of W2, a trailing side seating surface with a slot depth of W1, an inner angle side seating surface extending between the leading side surface and the trailing side surface, and an outer side surface, wherein W2 is smaller than W1.

2. The gear cutting tool according to claim 1, wherein: The anterior side surface is parallel to the caudal side surface, and wherein the inner angle side surface intersects the anterior side surface and defines an intersection angle α1 greater than 90 degrees, and wherein the inner angle side surface intersects the caudal side surface and defines an intersection angle α2 less than 90 degrees.

3. The gear cutting tool according to claim 1, wherein: The lateral side surface is perpendicular to the anterior side and the caudal side.

4. The gear cutting tool of claim 1, further comprising a cutting blade positioned in the at least one quadrilateral and non-rectangular blade receiving slot.

5. The gear cutting tool according to claim 4, wherein: The cross-sectional shape of the cutting blade is complementary in shape to the cross-sectional shape of the at least one said quadrilateral and non-rectangular blade receiving slot.

6. The gear cutting tool according to claim 1, wherein: The cutter head also includes a radial shim spacer block, thereby increasing the radial blade position distance of the cutting blade from the rotational axis.

7. The gear cutting tool according to claim 7, wherein: The radial shim spacer block is configured to receive a pentagonal cutting blade mounted therein.

8. A cutter head for a gear cutting tool, the cutter head having an axis of rotation and comprising a plurality of cutting blade receiving slots, wherein: Relative to the direction in which the cutter head rotates around the rotation axis during the gear cutting process, the axial cross-section of at least one of the receiving slots is a non-rectangular quadrilateral and the at least one of the receiving slots includes a front side surface with a slot depth of W2, a rear side seating surface with a slot depth of W1, an inner angle side seating surface extending between the front side surface and the rear side surface, and an outer side surface, wherein W2 is smaller than W1.

9. The cutter head of claim 8, further comprising a radial shim spacer block, whereby a radial blade position distance of the cutting blade from the rotational axis is increased.

10. The cutter head according to claim 7, wherein: The radial shim spacer block is configured to receive a pentagonal cutting blade mounted therein.

11. A cutting blade for a gear cutting tool, the cutting blade having a non-rectangular quadrilateral cross-section and comprising an outer side surface, a leading side surface, a trailing contact side surface and an inner corner contact side surface relative to the orientation of the cutting blade positioned in a cutter head during a gear cutting process.

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