Method for machining a pinion with offset helical tooth surfaces engaging a large helix angle spur gear

Abstract

The application relates to a machining method of a bias spiral tooth surface gear engaged with a large-spiral-angle cylindrical gear, wherein a gear cutting tool c1 is a involute spiral conical structure, the application sets the spiral angle of the gear cutting tool's division circle to be determined by the spiral angle of the cylindrical gear's division circle and the included angle of the two, sets the equivalent number of teeth of the cylindrical gear to be equal to the equivalent number of teeth of the gear cutting tool, calculates the number of teeth of the gear cutting tool, provides additional motion, and can ensure the feeding motion of the gear cutting tool or the to-be-machined face gear along the central axis direction of the cylindrical gear, and the rotary motion of the gear cutting tool and the to-be-machined face gear is a spiral motion. The gear cutting tool is simple in design and low in manufacturing cost, the gear cutting machining solves the problem that the large-spiral-angle bias face gear cannot be developed and machined, improves the machining efficiency of the bias spiral tooth surface gear, reduces the manufacturing cost of the complex face gear, and ensures that the gear cutting tool and the to-be-machined face gear will not interfere with each other in the actual gear cutting process.

Description

Technical fields:

[0001] This invention relates to the technical field of continuous and efficient generating processing of offset surface gears with large helix angles, specifically to a method for processing offset helical tooth surface gears that mesh with cylindrical gears with large helix angles. Background technology:

[0002] Face gear transmission is a type of gear transmission in which a cylindrical gear meshes with a face gear that has a variable module, variable pressure angle, and variable tooth thickness. Based on the tooth structure of the meshing cylindrical gear, it includes two common types: spur face gears and helical face gears. It can be applied to transmissions where the axes of the cylindrical gear and the face gear are orthogonal or non-orthogonal, or offset. The offset transmission form of the cylindrical gear (hereinafter referred to as the pinion) greatly expands the application range of face gear transmission, providing designers with greater creative freedom. The offset of the pinion axis helps to lower the height of the machine's center of gravity, and the use of straddle supports can significantly improve the rigidity of the system, while also resulting in a compact structure and convenient installation.

[0003] Face gears are machined differently from ordinary cylindrical gears and bevel gears. The machining location is on the end face of the cylindrical blank, not on the side of the cylindrical blank. Therefore, they can only be machined on special machine tools and cannot be machined directly on existing machine tools. Furthermore, because the tooth profile of face gears is relatively complex and the tooth thickness varies unevenly along the tooth width direction, face gears must be machined using the generating method, and cannot be machined using the contouring method like ordinary cylindrical gears.

[0004] Currently, traditional generating methods suitable for spur gears include gear shaping, worm hobbing, and worm grinding. However, these methods cannot be used to process helical gears due to their low processing efficiency, extremely complex tool design and manufacturing, and the need for costly specialized machine tools. Machining helical gears has always been an industry challenge. In recent years, gear turning has emerged as a generating method for spur gears. In patent number "201910646817.9", titled "A Method for Machining Face Gears", a method for machining face gears with intersecting axes is provided. This method involves using a helical bevel gear as the cutting cutter, with a set difference between the helix angle β0 of the cutting cutter and the helix angle β of the face gear to be machined. During the generating gear machining process, the rotation axis of the cutting cutter and the rotation axis of the face gear to be machined maintain a set axial intersection angle Σ, and the cutting cutter and the face gear to be machined maintain a set speed ratio Ur. The offset distance E between the rotation axis of the cutting cutter and the rotation axis of the face gear to be machined is continuously adjusted, and the cutting cutter is fed axially to machine a spur gear. Furthermore, in patent number "201921123382.1", titled "A Gear Turning Machine Tool for Machining Face Gears", a five-axis linkage CNC machine tool structure for machining face gears with intersecting axes is presented to overcome the existing problems in the "A Method for Machining Face Gears".

[0005] The big helix angle bias face gear transmission is composed of a helical gear with helix angle greater than 25° and a plane gear with variable helix angle along the tooth direction. Due to the particularity of the tooth structure of the bias helical face gear meshing with the big helix angle cylindrical gear and the high complexity of the tooth surface, the above-mentioned gear tooth turning and generating machining technology, including the arrangement technology of the gear turning cutter and the machined face gear, and the cutter parameter design technology related thereto, cannot meet the machining requirements of the bias helical face gear meshing with the big helix angle cylindrical gear. SUMMARY

[0006] The present application provides a machining method of a bias helical face gear meshing with a big helix angle cylindrical gear to solve the problem that the helical face gear cannot be continuously generated by the existing gear shaping, gear hobbing and gear turning methods.

[0007] In order to achieve the above-mentioned purpose, the technical solution provided by the present application is as follows: a machining method of a bias helical face gear meshing with a big helix angle cylindrical gear, comprising the following steps:

[0008] Step one, a gear turning cutter c1 is installed on the spindle of a gear turning machining numerical control machine tool or a multi-axis linkage machining center, the included angle between the central axis of the gear turning cutter c1 and the central rotation axis of the helical cylindrical gear in the horizontal plane is γ, and γ = arcsin(E / R2)

[0009] E is the bias distance of the bias helical face gear h2 and the involute helical cylindrical gear h1 meshing with the bias helical face gear h2; R2 is the outer radius of the bias helical face gear h2;

[0010] Step two, the blank of the bias helical face gear h2 to be machined is installed on the workbench of the shaft capable of controlling the rotation of the blank;

[0011] Step three, the gear turning cutter c1 is quickly aligned and positioned at the gear turning machining starting point of the bias helical face gear h2, the axis of the gear turning cutter c1 and the axis of the involute helical cylindrical gear h1 have an axial intersection angle, and the axial intersection angle is the included angle between the central axis of the gear turning cutter c1 and the central rotation axis of the involute helical cylindrical gear h1 in the horizontal plane, which is represented as

[0012] γ = arcsin(E / R2) (1)

[0013] Step four, the gear turning cutter c1 rotates at ω c at a high speed around the spindle of the numerical control machine tool, and the bias helical face gear h2 meshes with the gear turning cutter c1 at a certain transmission ratio m 2cDuring the generating motion, within one meshing cycle from the start of gear engagement to complete disengagement, the cutting edge encloses a narrow band-shaped area on the workpiece tooth surface. Simultaneously, the gear cutting tool c1 or the offset helical gear h2 to be machined provides continuous linear feed motion. Within one meshing cycle of rotation around the CNC machine tool spindle, it translates a small distance along the axis of the involute helical cylindrical gear h1 until the entire tooth width is machined, obtaining a complete large helix angle offset helical gear.

[0014] Furthermore, in step one above, the gear cutting tool c1 is an involute helical conical structure, the helix angle of the gear cutting tool c1 is β0, the number of teeth of the gear cutting tool c1 is Z0, the gear cutting tool c1 produces a rake angle and a clearance angle, and the cutting edge of the tool is the intersection of the involute helical surface and the inner conical surface.

[0015] Furthermore, in step one above, the helix angle of the involute helical cylindrical gear h1 meshing with the offset helical gear h2 is β1, and the helix angle β0 of the cutting tool c1 and the helix angle β1 of the involute helical cylindrical gear h1 have the same direction of rotation; other normal parameters of the cutting tool c1, such as the normal module m, are as follows: n0 Normal pressure angle α n0 Tooth tip height coefficient porosity and displacement coefficient The normal parameters corresponding to the involute helical cylindrical gear h1 are, for example, the normal module m. n1 Normal pressure angle α n1 Tooth tip height coefficient porosity and displacement coefficient Same as;

[0016] Furthermore, in step one above, the formula for calculating the pitch circle helix angle β0 of the gear cutting tool c1 is:

[0017] β0=β1-γ (2)

[0018] Wherein, β0 is the pitch circle helix angle of the gear cutting tool c1, and β1 is the pitch circle helix angle of the cylindrical gear meshing with the offset helical gear h2; it is required that β0 is less than β1, and the helical directions of β0 and β1 are the same.

[0019] Furthermore, in step one above, the number of teeth Z0 of the gear-cutting tool c1 is calculated according to the following steps:

[0020] Z'0=Z0 / cos 3 β0 (3)

[0021] Z'1=Z1 / cos 3 β1 (4)

[0022] Z'0 = Z'1 (5)

[0023] The obtained Z0 is rounded to an integer in the direction of the numerical value increase, and the actual tooth number Z0 of the gear cutting tool c1 is obtained. Wherein, Z1 is the tooth number of the involute helical cylindrical gear h1, and β1 is the helix angle of the involute helical cylindrical gear h1 engaged with the offset spiral tooth surface gear h2.

[0024] Further, in the above step four, the additional rotation angular velocity of the gear cutting tool c1 is calculated as follows,

[0025]

[0026] Further, the gear cutting tool c1 provides additional rotation, and the actual rotation angular velocity relationship of the gear cutting tool c1 in gear cutting is

[0027]

[0028] Further, the offset spiral tooth surface gear h2 provides additional rotation, and the actual rotation angular velocity relationship of the gear cutting tool c1 in gear cutting is

[0029]

[0030] Wherein, Z0 represents the tooth number of the gear cutting tool c1; β0 represents the helix angle of the gear cutting tool c1; m n0 is the normal module of the gear cutting tool c1; v 2c is the feed speed of the gear cutting tool c1 or the offset spiral tooth surface gear h2 along the axial direction of the involute helical cylindrical gear h1 engaged with the offset spiral tooth surface gear h2; m 2c is the tooth number ratio of the gear cutting tool c1 and the offset spiral tooth surface gear h2 to be machined in gear cutting.

[0031] Further, when the gear cutting tool c1 or the offset spiral tooth surface gear h2 to be machined also has a feed motion along the straight line direction of the center rotation axis h1-x of the involute helical cylindrical gear h1 engaged with the actual offset spiral tooth surface gear h2, the actual transmission ratio between the gear cutting tool c1 and the offset spiral tooth surface gear h2 to be machined is represented as,

[0032]

[0033] Further, the above assumes that the contact point M of the gear cutting tool c1 and the offset spiral tooth surface gear h2 is the point M, and the speed of the contact point M when the gear cutting tool c1 moves is The vector expression is:

[0034] The speed of the contact point M when the offset spiral tooth surface gear h2 moves is The vector expression is,

[0035]

[0036] The linear feed speed of the gear tooth cutter c1 and the offset helical face gear h2 at the contact point M is

[0037]

[0038] Wherein, is the angular velocity vector of the gear tooth cutter c1, is the position vector of the gear tooth cutter c1 at the contact point M; is the angular velocity vector of the offset helical face gear h2, is the position vector of the offset helical face gear h2 at the contact point M, is the moving speed vector of the offset helical face gear h2 along the direction of the axis of the involute helical cylindrical gear h1.

[0039] Compared with the prior art, the present application has the following advantages:

[0040] 1. The gear tooth cutter c1 machining the offset helical face gear h2 is based on the principle of spatial intersection axis two-degree-of-freedom conjugate meshing for spatial generating machining. During machining, the center axis of the gear tooth cutter c1 and the center axis of the gear to be machined are in spatial intersection line, both of which rotate at high speed with transmission ratio and do forced meshing movement, at the same time, the gear tooth cutter c1 or the gear to be machined moves linearly along the rotation axis of the cylindrical gear, and the relative speed of the gear tooth cutter c1 relative to the gear to be machined along the tooth direction and the tooth profile direction removes the material. Since the gear tooth cutter c1 rotates at very high speed and there is no empty return stroke during machining, the machining efficiency is several times that of transmission gear cutting.

[0041] 2. The gear tooth cutter c1 is involute helical conical structure, and the design of the gear tooth cutter c1 is much simpler than that of the gear hobbing, and the manufacturing cost is lower. The gear tooth machining solves the problem of non-generating machining of large helix angle offset face gear, greatly improves the machining efficiency of the offset helical face gear h2, and greatly reduces the manufacturing cost of the complex face gear. The specific analysis is as follows:

[0042] (1) During the gear tooth cutter c1 machining the offset helical face gear h2, the existence of the intersection angle between the center axis c1-x of the gear tooth cutter c1 and the center rotation axis h1-x of the involute helical cylindrical gear h1 ensures the actual cutting speed and determines the improvement of the machining efficiency.

[0043] (2) During the gear tooth cutter c1 machining the offset helical face gear h2, the present application sets the dividing circle helix angle β0 of the gear tooth cutter c1, which is determined by the dividing circle helix angle β1 of the involute helical cylindrical gear h1 and the included angle γ between them, to ensure that there is no interference between the gear tooth cutter c1 and the machined face gear during the actual gear cutting process.

[0044] (3)Based on the principle of equivalent gear, the present application sets the equivalent teeth number of involute helical cylindrical gear h1 equal to the equivalent teeth number of gear cutting tool c1, and calculates the teeth number of gear cutting tool c1. In the case of ensuring the same tooth profile angle, the normal tooth profile of gear cutting tool c1 and the normal tooth profile of involute helical cylindrical gear h1 meshing with the offset helical face gear h2 are ensured to be the same, so that the gear cutting tool c1 can mesh with the involute helical cylindrical gear h1 tooth profile meshing point of the offset helical face gear h2 to be machined.

[0045] 4、In the method provided by the present application, when the offset helical face gear h2 is machined, the additional motion is provided, so that the feeding motion of gear cutting tool c1 or the offset helical face gear h2 to be machined along the central axis h1-x of the involute helical cylindrical gear h1 and the rotation motion of gear cutting tool c1 and the offset helical face gear h2 to be machined are a helical motion. The gear cutting tool c1 or the offset helical face gear h2 can provide additional rotation, which is convenient to implement.

[0046] 6、Wide application range: the present application can not only be applied to the machining of the offset helical face gear with large helical angle cylindrical gear, but also be applied to the high-efficiency gear cutting generating machining of the straight tooth offset face gear, the design and calculation of the cutter parameters are the same as the calculation and determination method of the gear cutting tool parameters of the present application, and the applicability is high. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a structural schematic view of the meshing of the face gear and the straight tooth cylindrical gear;

[0048] Figure 2 is a structural schematic view of the meshing of the helical face gear and the involute helical cylindrical gear;

[0049] Figure 3 is a structural schematic view of the meshing of the offset helical face gear and the helical angle of the helical tooth cylindrical gear greater than 25°;

[0050] Figure 4 is a structural schematic view of the intersection angle of the helical tooth cylindrical gear axis and the gear cutting tool horizontal axis;

[0051] Figure 5 、 Figure 6 is a structural schematic view of the motion relationship when the helical tooth gear cutting tool continuously generates the offset helical face gear. DETAILED DESCRIPTION

[0052] The present application will be described in detail below in combination with the drawings and examples.

[0053] According to the cylindrical gear tooth structure form of meshing, the face gear meshing with the straight tooth cylindrical gear p1 is defined as the straight tooth face gear p2 (seeFigure 1 ), and the helical gear ph2 that meshes with the helical cylindrical gear ph1. Figure 2 Two common types are available, applicable to transmissions where the axes of the cylindrical gear and the face gear are orthogonal or non-orthogonal, or where the axes are offset. The large helix angle offset face gear transmission consists of a helical involute cylindrical gear h1 with a helix angle greater than 25° and an offset helical face gear h2, such as... Figure 3 As shown, the tooth structure of the offset helical gear h2 is highly complex.

[0054] Therefore, the present invention provides a method for machining offset helical tooth surface gears that mesh with large helix angle cylindrical gears, see [link to relevant documentation]. Figure 5 and Figure 6 This includes the following steps:

[0055] Step 1: Install the gear cutting tool c1 on the spindle of a gear-turning CNC machine tool or a multi-axis CNC machining center.

[0056] The central rotation axis h1-x of the large helix angle involute helical cylindrical gear h1 and the central rotation axis h2-x of the large helix angle offset helical tooth surface gear h2 are spatially skew lines. The distance between the two lines is called the offset distance E of the two gears. The sign of the offset distance E is specifically determined in the generating method machining coordinate system.

[0057] The gear cutting tool c1 used has an involute helical conical structure with a helix angle of β0 and a number of teeth of Z0. The cutting tool c1 creates a rake angle and a clearance angle. The cutting edge of the tool is the intersection of the involute helical surface and the inner conical surface. The central axis of rotation c1-x of the gear cutting tool c1 and the central axis of rotation h2-x of the offset helical gear h2 are spatially intersecting straight lines. Simultaneously, the central axis of rotation c1-x of the gear cutting tool c1 and the central axis of rotation h1-x of the involute helical cylindrical gear h1 are spatially skew lines. The angle γ between these two lines in the horizontal plane is called the axis angle (e.g., ...). Figure 4 ).

[0058] During the continuous generating process of the offset helical gear h2 using the gear cutting tool c1, the gear cutting tool c1 and the offset helical gear h2 to be machined undergo two relative movements: first, the gear cutting tool c1 and the offset helical gear h2 to be machined move at angular velocities ω... c The transmission ratio m between ω2 and ω2 rotation. 2c constant (e.g.) Figure 5 Secondly, in order to machine the full tooth width of the offset helical gear h2, the gear cutting tool c1 or the offset helical gear h2 needs to provide a feed motion v along the straight line h1-x, which is the central axis of rotation of the involute helical cylindrical gear h1. 2c, while providing certain additional rotation (e.g. Figure 6 ). Both are based on the transmission ratio m 2c High-speed rotation and feed motion, according to the processing principle of the generating method, the cutting edge of the gear cutting tool c1 can envelope a space curved surface, until the complete large helix angle offset helical gear h2 is obtained.

[0059] It should be noted that: the helix angle of the involute helical cylindrical gear h1 engaged with the offset helical gear h2 is β1, and the helix angle β0 of the gear cutting tool c1 and the helix angle β1 of the involute helical cylindrical gear h1 are the same in rotation direction; the other normal surface parameters of the gear cutting tool c1 such as normal module m n0 , normal pressure angle α n0 , addendum coefficient , dedendum coefficient and modification coefficient corresponding to the normal surface parameters of the involute helical cylindrical gear h1 such as normal module m n1 , normal pressure angle α n1 , addendum coefficient , dedendum coefficient and modification coefficient are the same.

[0060] It is said that the center axis c1-x of the gear cutting tool c1 and the center rotation axis h1-x of the involute helical cylindrical gear h1 belong to space different surface straight lines, and the included angle γ between the two straight lines in the horizontal plane can be calculated by the geometric relationship. Figure 4 Figure 4 In the formula, the parameter E is the distance between the center rotation axis h1-x of the involute helical cylindrical gear h1 and the center rotation axis h2-x of the offset helical gear h2, that is, the offset distance of the assembly, the tool axis c1-x, the cylindrical gear axis h1-x and the geometric outer radius R2 of the offset helical gear h2 determine the intersection of the circle at point M, and γ is represented as,

[0061] γ = arcsin (E / R2) (1)

[0062] In the formula, R2 is the given outer radius of the offset helical gear h2 to be processed.

[0063] It is said that the center axis c1-x of the gear cutting tool c1 and the center rotation axis h1-x of the involute helical cylindrical gear h1 belong to space different surface straight lines, and the included angle γ between the two center axes in the horizontal projection plane is obtained by formula (1) under the premise that the dividing circle helix angle β0 of the gear cutting tool c1 is limited, and the dividing circle helix angle β0 of the gear cutting tool c1 is obtained by the following calculation formula:

[0064] β0 = β1-γ (2)

[0065] ​Wherein, β0 is the c1 indexing circle helix angle of the gear tooth cutter, and β1 is the indexing circle helix angle of the h1 involute helical cylindrical gear meshing with the h2 offset helical tooth surface gear. It is required that β0 is less than β1, and the helix directions of β0 and β1 are the same.

[0066] According to the principle of the equivalent gear of the helical gear, if the gear number Z0 of the gear tooth cutter c1 and the gear number Z1 of the h1 involute helical cylindrical gear meshing with the h2 offset helical tooth surface gear, then the equivalent gear number Z'0 of the gear tooth cutter c1 is equal to the equivalent gear number Z'1 of the h1 involute helical cylindrical gear. Under the condition that the indexing circle helix angle β0 of the gear tooth cutter c1 is determined, the gear number Z0 of the gear tooth cutter c1 is calculated according to the following steps:

[0067] Z'0 = Z0 / cos 3 β0 (3)

[0068] Z'1 = Z1 / cos 3 β1 (4)

[0069] Z'0 = Z'1 (5)

[0070] The obtained Z0 is rounded to an integer in the increasing direction according to the design requirements, and the actual gear number Z0 of the gear tooth cutter c1 is obtained. Wherein, Z1 is the gear number of the h1 involute helical cylindrical gear, and β1 is the helix angle of the h1 involute helical cylindrical gear meshing with the h2 offset helical tooth surface gear.

[0071] Step two, the h2 offset helical tooth surface gear blank to be machined is installed on the workbench of the shaft capable of controlling the rotational motion thereof.

[0072] Step three, the gear tooth cutter c1 is quickly set up, positioned at the gear tooth machining starting point of the h2 offset helical tooth surface gear, and the cutter axis and the h2 offset helical tooth surface gear axis have an axis intersection angle. The axis intersection angle is the included angle between the center axis of the gear tooth cutter c1 and the center axis of revolution of the h1 involute helical cylindrical gear in the horizontal plane, which is represented as γ = arcsin (E / R2).

[0073] Step four, the gear tooth cutter c1 is rotated at a high speed ω c around the main shaft of the numerical control machine tool, and the h2 offset helical tooth surface gear is driven to rotate at a certain transmission ratio m 2c . In one meshing period from the beginning of the engagement to the complete exit of the gear tooth cutter c1 and the h2 offset helical tooth surface gear, the cutting edge envelopes a narrow strip-shaped area on the workpiece tooth surface. At the same time, the gear tooth cutter c1 or the h2 offset helical tooth surface gear to be machined provides continuous linear feed motion, and in one meshing period of rotation around the main shaft of the numerical control machine tool, the h2 offset helical tooth surface gear translates a small distance along the axis of the h1 involute helical cylindrical gear, until the entire tooth width is machined, and a complete large helix angle offset helical tooth surface gear is obtained.

[0074] The detailed description is as follows:

[0075] 1. In the process of continuously generating a bias helical face gear h2 with a gear tooth cutter, the gear tooth cutter c1 and the bias helical face gear h2 to be machined need to make two relative movements: one is that the gear tooth cutter c1 and the bias helical face gear h2 to be machined rotate at angular velocities ω c and ω2, and the transmission ratio m 2c between them is constant (such as Figure 5 ); the other is that in order to machine the full tooth width of the bias helical face gear h2 to be machined, the gear tooth cutter c1 or the bias helical face gear h2 to be machined needs to provide a feed motion v 2c along the straight line of the center rotation axis h1-x of the involute helical cylindrical gear h1, and also provide a certain additional rotation (such as Figure 6 ). Based on the transmission ratio m 2c high-speed rotation and the feed motion, according to the generating principle, the cutting edge of the gear tooth cutter c1 can envelope a space curve, and a complete large helix angle bias helical face gear h2 can be machined.

[0076] 2. On the basis of calculating the gear number Z0 and the helix angle β0 of the gear tooth cutter c1, the rotational angular velocity ratio of the gear tooth cutter c1 and the bias helical face gear h2 to be machined is further limited, and the rotational angular velocity ratio is,

[0077]

[0078] wherein ω c is the rotational angular velocity of the gear tooth cutter c1, ω2 is the rotational angular velocity of the bias helical face gear h2, Z0 is the gear number of the gear tooth cutter c1, and Z2 is the gear number of the bias helical face gear h2.

[0079] Since the gear tooth cutter c1 and the bias helical face gear h2 to be machined have a space meshing transmission relationship, the gear tooth cutter c1 or the bias helical face gear h2 to be machined also has a feed motion along the straight line of the center rotation axis h1-x of the involute helical cylindrical gear h1 which meshes with the actual bias helical face gear h2, and therefore the gear tooth cutter c1 or the bias helical face gear h2 to be machined needs to provide a certain additional rotation, so as to machine a face gear tooth structure with variable tooth thickness and variable helix angle. The additional rotational angular velocity of the gear tooth cutter c1 is calculated as follows based on the rotational angular velocity of the gear tooth cutter c1, the helix angle β0 of the gear tooth cutter c1, the gear number Z0 of the gear tooth cutter c1, and the feed speed along the center rotation axis h1-x of the involute helical cylindrical gear h1 which meshes with the bias helical face gear h2,

[0080]

[0081] If additional rotation is provided by the gear tooth cutter cl, the actual rotation angular velocity relationship of the gear tooth cutter cl in gear tooth machining is

[0082]

[0083] If additional rotation is provided by the offset helical tooth face gear h2, the actual rotation angular velocity relationship of the gear tooth cutter cl in gear tooth machining is

[0084]

[0085] Wherein, Z0 represents the number of teeth of the gear tooth cutter cl; β0 represents the helix angle of the gear tooth cutter cl; m n0 is the normal module of the gear tooth cutter cl; v 2c is the feed speed provided by the gear tooth cutter cl or the offset helical tooth face gear h2 along the axial direction of the involute helical spur gear h1 engaged with the offset helical tooth face gear h2; m 2c is the tooth number ratio of the gear tooth cutter cl and the offset helical tooth face gear h2 in gear tooth machining.

[0086] 4. In the generating machining process of the offset helical tooth face gear h2 by the gear tooth cutter cl, the gear tooth cutter cl and the offset helical tooth face gear h2 to be machined are engaged according to a certain transmission ratio, and there is a feed motion of the gear tooth cutter cl or the offset helical tooth face gear h2 along the straight line direction of the central rotation axis h1-x of the involute helical spur gear h1 engaged with the actual offset helical tooth face gear h2, the actual transmission ratio between the gear tooth cutter cl and the offset helical tooth face gear h2 to be machined is

[0087]

[0088] It is assumed that the contact point M between the gear tooth cutter cl and the offset helical tooth face gear h2 is the point M, the speed of the contact point M when the gear tooth cutter cl moves is The vector expression is:

[0089] The speed of the contact point M when the offset helical tooth face gear h2 moves is The vector expression is,

[0090] The relative motion speed v of the gear tooth cutter cl and the offset helical tooth face gear h2 at the contact point M is (02) The vector expression is,

[0091]

[0092] Wherein, is the angular velocity vector of the gear tooth cutter cl, is the position vector of the face gear h2 at the contact point M. is the angular velocity vector of the face gear h2, is the position vector of the face gear h2 at the contact point M. is the moving velocity vector of the face gear h2 along the axis direction of the involute helical cylindrical gear h1.

[0093] The offset distance E of the face gear h2 from the involute helical cylindrical gear h1 with which the face gear h2 meshes, i.e. the distance between the face gear h2 and the central axis of the involute helical cylindrical gear h1, is further described. The positive and negative of the offset distance E is determined in the generating method processing coordinate system.

[0094] According to the above processing method, two specific examples are given below for illustration:

[0095] 1. High-efficiency face gear machining of large helix angle offset face gear:

[0096] Design conditions: the number of teeth Z1 of the involute helical cylindrical gear h1 meshing with the face gear h2 is 7, the helix angle β1 is 53° (left-handed), the normal modulus m n1 = 0.85 mm, the pressure angle a n1 = 20°, the addendum coefficient h * an1 = 1.0, the dedendum coefficient c * n1 = 0.25, the modification coefficient x * n1 = 0.2, the number of teeth Z2 of the face gear is 34, the offset distance E is -7.5 mm, the inner radius R1 of the face gear is 16.8 mm, the outer radius R2 of the face gear is 19.8 mm, and the shaft included angle Σ is 90° (offset).

[0097] Reference design scheme: according to the design conditions, the geometric dimensions of the face gear cutter c1 are calculated as follows: the number of teeth Z0 is 21, the normal modulus m n0 = 0.85 mm, the normal pressure angle a n0 = 20°, the shaft intersection angle γ = 22.2586°, the rotation direction of the face gear cutter c1 is left-handed, the helix angle β0 = 30.7414°, the normal addendum angle δ o = 5°, the normal dedendum angle δ f = 10°, the normal addendum coefficient h * an0 = 1.0, the normal dedendum coefficient c * n0 = 0.25, the normal modification coefficient x * n0 = 0.2, and the root radius r = 0.2 mm.

[0098] 2. High efficiency gear hobbing of large helix angle offset face gear h2

[0099] Design condition: the number of teeth Z1 = 6, helix angle β1 = 61° (left hand), normal module m n1 = 0.6 mm, pressure angle a n1 = 20°, addendum coefficient h * an1 = 1.1, dedendum coefficient c * n1 = 0.25, modification coefficient x * n1 = 0.4203, the number of teeth of face gear Z2 = 37, offset distance E = -6.45 mm, face gear inner radius R1 = 13 mm, face gear outer radius R2 = 16 mm, shaft angle Σ = 90° (offset).

[0100] Reference design: according to the design condition, the geometric dimensions of hobbing tool c1 are calculated as follows: the number of teeth Z0 = 27, normal module m n0 = 0.6 mm, normal pressure angle a n0 = 20°, shaft intersection angle γ = 23.7737°, the rotation direction of hobbing tool c1 is left hand, helix angle β0 = 37.2263°, tool rake angle δ o = 2.5°, tool relief angle δ f = 12°, normal addendum coefficient h * an0 = 1.1, normal dedendum coefficient c * n0 = 0.25, normal modification coefficient x * n0 = 0.4203, root radius r = 0.2 mm.

[0101] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification according to the technical essence of the present application to the above embodiment are still within the protection scope of the technical solution of the present application.

Claims

1. A method of machining a large helix angle offset spiral bevel gear in mesh with an involute spiral bevel gear, characterized by: It comprises the following steps: Step one, install the gear turning tool (c1) on the spindle of the gear turning numerical control machine tool or multi-axis linkage numerical control machining center, the included angle between the central axis of the gear turning tool (c1) and the center rotation axis of the involute spiral cylindrical gear in the horizontal plane is γ, γ = arcsin (E / R2) E is the offset distance of the offset spiral tooth surface gear (h2) and the involute spiral cylindrical gear (h1) engaged with it; R2 is the outer radius of the offset spiral tooth surface gear (h2); Step two, the blank of the offset spiral tooth surface gear (h2) to be processed is installed on the workbench capable of controlling its rotation; Step three, the gear turning tool (c1) is quickly calibrated and positioned at the gear turning processing starting point of the offset spiral tooth surface gear (h2), the gear turning tool (c1) axis and the involute spiral cylindrical gear (h1) axis have an axial intersection angle, the axial intersection angle is the included angle between the gear turning tool (c1) central axis and the involute spiral cylindrical gear (h1) center rotation axis in the horizontal plane, which is denoted as γ = arcsin (E / R2) (1) Step four, the gear cutting tool (c1) rotates around the spindle of the CNC machine or multi-axis CNC machining center at ω c High speed rotation, with the offset spiral tooth surface gear (h2) at a certain number of teeth ratio m 2c Doing the generating motion, in a tooth engagement to the complete exit of such a meshing cycle, the cutting edge in the workpiece tooth surface envelope a narrow strip area, while the gear cutting tool (c1) or the offset spiral tooth surface gear (h2) to be processed provides continuous linear feed motion, in a meshing cycle around the spindle of the CNC machine or multi-axis CNC machining center, along the axis of the involute spiral cylindrical gear (h1) to translate a small distance, until the entire tooth width is machined, and a complete large spiral angle offset spiral tooth surface gear is obtained.

2. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 1, characterized in that: In the step one, the gear turning tool (c1) is an involute spiral conical structure, the spiral angle of the gear turning tool (c1) is β0, the tooth number of the gear turning tool (c1) is Z0, the gear turning tool (c1) is manufactured with a rake angle and a relief angle, and the cutting edge of the gear turning tool is the intersection line of the involute spiral curved surface and the inner conical surface.

3. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 2, characterized in that: The helix angle of the involute helical cylindrical gear (h1) engaged with the bias helical gear (h2) in the step one is β1, and the helix angle β0 of the cutter (c1) and the helix angle β1 of the involute helical cylindrical gear (h1) have the same rotation direction; the normal module m n0 , the normal pressure angle α n0 , the addendum coefficient , the dedendum coefficient , and the modification coefficient of the cutter (c1) are the same as those of the involute helical cylindrical gear (h1). n1 , the normal pressure angle α n1 , the addendum coefficient , the dedendum coefficient , and the modification coefficient of the cutter (c1) are the same as those of the involute helical cylindrical gear (h1).

4. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear according to claim 3, characterized in that: In the step one, the calculation formula of the spiral angle β0 of the gear turning tool (c1) is: β0 = β1-γ (2) Wherein, β0 is the spiral angle of the gear turning tool (c1), β1 is the spiral angle of the involute spiral cylindrical gear engaged with the offset spiral tooth surface gear (h2); it is required that β0 is less than β1, and the spiral directions of β0 and β1 are the same.

5. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 4, characterized in that: In the step one, the tooth number Z0 of the gear turning tool (c1) is calculated as follows: Z'0= Z0 / cos 3 β0 (3) Z'1 = Z1 / cos 3 β1 (4) Z'0 = Z'1 (5) Wherein, Z′0 is the equivalent tooth number of the gear turning tool (c1); Z′1 is the equivalent tooth number of the involute spiral cylindrical gear (h1) Increase the obtained Z0 to an integer in the value increasing direction to obtain the actual tooth number Z0 of the gear turning tool (c1). Wherein, Z1 is the tooth number of the involute spiral cylindrical gear (h1), and β1 is the spiral angle of the involute spiral cylindrical gear (h1) engaged with the offset spiral tooth surface gear (h2).

6. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as set forth in claim 5, characterized in that: In the step four, the additional rotation angle velocity of the gear turning tool (c1) is calculated as follows, wherein v 2c is the feed speed in axial direction of the involute helical cylindrical gear (h1) engaged with the offset helical tooth surface gear (h2) provided by the gear cutter (c1) or the offset helical tooth surface gear (h2).

7. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 6, characterized in that: The actual rotation angle velocity relationship of the gear turning tool is, 8. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 7, characterized in that: The actual rotation angle velocity relationship of the offset spiral tooth surface gear is, wherein ω2 is the theoretical rotational angular velocity of the offset helical tooth surface gear (h2) in the process of gear turning; ω'2 is the actual rotational angular velocity of the offset helical tooth surface gear (h2) in the process of gear turning; Z0 represents the number of teeth of the gear turning tool (c1); β0 represents the helix angle of the gear turning tool (c1); m n0 is the normal module of the gear turning tool (c1); v 2c is the feed speed provided by the gear turning tool (c1) or the offset helical tooth surface gear (h2) along the axial direction of the involute helical cylindrical gear (h1) engaged with the offset helical tooth surface gear (h2); m 2c is the gear ratio of the gear turning tool (c1) and the offset helical tooth surface gear (h2) to be machined.

9. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 8, characterized in that: When the gear turning tool (c1) or the offset spiral tooth surface gear (h2) to be processed has a feeding motion along the straight line direction of the center rotation axis h1-x of the involute spiral cylindrical gear (h1) engaged with the actual offset spiral tooth surface gear (h2), the actual transmission ratio between the gear turning tool (c1) and the offset spiral tooth surface gear (h2) to be processed is denoted as, Wherein, ω2 is the theoretical rotation angular velocity of the offset helical tooth surface gear (h2) in the process of machining the gear tooth; Z2 is the number of teeth of the offset helical tooth surface gear (h2).

10. A method of machining a large helix angle offset spiral bevel gear meshing with an involute spiral bevel gear as claimed in claim 9, characterized in that: The linear feed speed of the gear tooth cutter (c1) and the offset helical tooth surface gear (h2) at the contact point M is wherein is the angular velocity vector of the gear tooth cutter (c1), is the position vector of the gear tooth cutter (c1) at the point of contact M.

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