A precise modeling method for the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle

Abstract

The invention belongs to the technical field of bevel gear modeling, and discloses a method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle, including establishing a tooth blank model of a master gear and a slave gear; establishing a tool model of the master gear and the slave gear; establishing a machine tool model; using a generating method for the master gear and a forming method for the slave gear, respectively obtaining accurate models of the master gear and the slave gear. Compared with the prior art, the invention has higher modeling efficiency and high model accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of bevel gear modeling, and in particular to a method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle. Background Art

[0002] The tooth surface shape of the drive axle hypoid bevel gear is more complex than that of the involute cylindrical gear. In order to accurately evaluate the contact state of the tooth surface after force is applied and analyze the meshing performance of the bevel gear, it is necessary to establish a simulation calculation analysis model containing accurate tooth surface. The tooth surface shape of the bevel gear is not only related to the cutting edge parameters of the machining tool, but also to the motion parameters of the machine tool and the workpiece. At the same time, the tool can also be refined for different positions; there are many tooth surface control parameters, and the tooth surface of the bevel gear is a spatial surface, which makes the tooth surface modeling process of the bevel gear complicated and difficult.

[0003] At present, the precise modeling method of the tooth surface of the drive axle hypoid gear is usually to establish the tooth blank model without considering the micro-morphology, or to use the discrete method to establish the small wheel and large wheel model. Such precise modeling of the hypoid gear is not comprehensive, the modeling is not accurate enough, the efficiency is low, and it cannot support the performance analysis and calculation of the bevel gear. Summary of the invention

[0004] The object of the present invention is to provide a method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle, so as to solve the problems of low model accuracy and low efficiency.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle, comprising the following steps:

[0007] S1, establish the gear blank model of the master gear and the slave gear;

[0008] S2, establishing a tool model of the master gear and the slave gear;

[0009] S3, building a machine tool model;

[0010] S4, the main gear is formed by a developing method, and the slave gear is formed by a forming method, so as to obtain accurate models of the main gear and the slave gear respectively.

[0011] Optionally, step S1 specifically includes:

[0012] S11, inputting the macro parameters of the master gear and the slave gear into the Gleason bevel gear design software Gems;

[0013] S12, running the basic parameter design module of Gems software to obtain the design parameters required for establishing the gear blank models of the master gear and the slave gear;

[0014] S13, creating a two-dimensional sketch in CATIA software according to the design parameters;

[0015] S14, performing a rotation operation on the two-dimensional sketch to obtain the gear blank models of the master gear and the slave gear.

[0016] Optionally, the macro parameters include the number of teeth, hand direction, helix angle, pressure angle, pitch circle diameter of the tooth, tooth face width, pitch circle diameter, tooth height coefficient, tooth top height coefficient, cutter disc diameter, large wheel tip width and tip fillet radius.

[0017] Optionally, the design parameters include the number of teeth, tooth width, offset distance, axis angle, external cone distance, tooth top height, tooth root height, pitch cone offset, pitch cone angle, face cone angle, root cone angle, rotation direction and processing method.

[0018] Optionally, the method for establishing the tool model of the slave gear in step S2 is:

[0019] A two-dimensional tool curve is established in CATIA software according to tool parameters; and then the two-dimensional tool curve is rotated to obtain the tool model of the slave gear.

[0020] Optionally, the tool model of the main gear in step S2 is established by a tool equation, and the tool equation includes a tool point vector equation and a normal vector equation. For straight line shaping, the tool point vector equation and the normal vector equation are:

[0021]

[0022] For curve modification, the tool point vector equation and normal vector equation are:

[0023]

[0024] In the formula, F C (x, y, z) represents any point on the cutter head (x, y, z); N C (x, y, z) is the normal vector of any point (x, y, z) on the tool profile; θ is the tool rotation parameter, s is the distance from any point on the tool profile to the tool top, R is the shaping radius, R O R is the radius of the outer cutter disc, I is the radius of the outer cutter disc, α is the pressure angle, It is the angle from any point on the tool profile to the tool top.

[0025] Optionally, step S3 specifically includes:

[0026] Running the macro parameters and the tool parameters in the bevel gear parameter design software Gems to obtain the machine tool parameters required for the master gear and the slave gear;

[0027] In the machine tool coordinate system, establish the machine tool kinematic chain matrix.

[0028] Optionally, the forming method is specifically:

[0029] Determine the positional relationship between the tooth blank model of the slave gear and the tool model according to the horizontal tool position and the vertical tool position;

[0030] Setting the tool model as a working object, and performing cutting simulation on the tooth blank model of the slave gear through Boolean operation;

[0031] After the tooth surface array is formed by cutting, an accurate model of the slave gear is obtained.

[0032] Optionally, the development method is specifically:

[0033] S41, establishing the tooth surface equation of the main gear and performing discretization processing;

[0034] S42, importing the discretized tooth surface point coordinates of the main gear into CATIA software to obtain the spatial geometric relationship of the tooth surface points;

[0035] S43, through insert-create surface-mesh surface point operation, all concave tooth long lines and convex tooth long lines are set as guide lines, and all concave tooth height lines and convex tooth height lines are set as contour lines, so as to obtain the tooth surface of the main gear;

[0036] S44, performing Boolean operation on the obtained tooth surface array of the main gear and the tooth blank model of the main gear to obtain an accurate model of the main gear.

[0037] Optionally, the tooth surface equation of the main gear in step S41 is solved by an iterative approximation algorithm based on a surface parameter curve.

[0038] Beneficial effects of the present invention:

[0039] The invention provides a method for accurately modeling the tooth surface of a quasi-hyperbolic spiral bevel gear of a passenger car drive axle. During the modeling process of the bevel gear of the drive axle, a tooth blank model, a tool model and a machine tool model are established, and then an accurate model of the main gear can be established by a developing method, and an accurate model of the slave gear can be established by a forming method. Compared with the prior art, the modeling efficiency and accuracy are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention is a flow chart of a method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0042] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0045] The present invention provides a method for accurately modeling the tooth surface of a hypoid spiral bevel gear of a passenger car drive axle. Figure 1 As shown, the following steps are included:

[0046] S1, establish the gear blank model of the master gear and the slave gear;

[0047] S2, establishing tool models of the master gear and slave gear;

[0048] S3, building a machine tool model;

[0049] S4, the main gear adopts the developing method, and the slave gear adopts the forming method, and the accurate models of the main gear and the slave gear are obtained respectively.

[0050] The invention provides a method for accurately modeling the tooth surface of a quasi-hyperbolic spiral bevel gear of a passenger car drive axle. During the modeling process of the bevel gear of the drive axle, a tooth blank model, a tool model and a machine tool model are established, and then an accurate model of the main gear can be established by a developing method, and an accurate model of the slave gear can be established by a forming method. Compared with the prior art, the modeling efficiency and accuracy are high.

[0051] The following is a method for establishing the specific tooth surface accurate model based on the master gear and the slave gear respectively.

[0052] Optionally, step S1 specifically includes:

[0053] S11, inputting the macro parameters of the master gear and the slave gear into the Gleason bevel gear design software Gems;

[0054] The macro parameters include the number of teeth, hand direction, helix angle, pressure angle, pitch circle diameter of the tooth, tooth face width, pitch circle diameter, tooth height coefficient, tooth top height coefficient, cutter head diameter, large wheel cutter tip width and cutter tip fillet radius.

[0055] S12, running the basic parameter design module of Gems software to obtain the design parameters required for establishing the gear blank models of the master gear blank and the slave gear;

[0056] The design parameters include the number of teeth, tooth width, offset, axis angle, external taper, tooth top height, tooth root height, pitch cone offset, pitch cone angle, face cone angle, root cone angle, hand direction and processing method. This embodiment uses CATIA software to establish the model.

[0057] S13, creating a two-dimensional sketch, i.e., a plane view, of the master gear and the slave gear in CATIA software according to the design parameters;

[0058] S14, rotating the 2D sketch to obtain the gear blank models of the master gear and the slave gear respectively. The gear blank model does not contain tooth groove features.

[0059] Optionally, the method for establishing the tool model of the gear in step S2 is:

[0060] A two-dimensional tool curve is established in CATIA software according to the tool parameters; then the two-dimensional tool curve is rotated to obtain the tool model of the gear.

[0061] Among them, the tool parameters are design values. Generally, the tool parameters are designed according to the performance requirements of the product, and mainly include: tool tip diameter, tool top distance, concave pressure angle, convex pressure angle, concave shaping radius, convex shaping radius, concave corner radius, convex corner radius, concave root digging height, concave root digging radius, convex root digging height and convex root digging radius.

[0062] Optionally, in step S2, the tool model of the main gear is established by a tool equation, and the tool equation includes a tool point vector equation and a normal vector equation. For straight line modification, the tool point vector equation and the normal vector equation are:

[0063]

[0064] For curve modification, the tool point vector equation and normal vector equation are:

[0065]

[0066] In the formula, F C (x, y, z) represents any point on the cutter head (x, y, z); N C (x, y, z) is the normal vector of any point (x, y, z) on the tool profile; θ is the tool rotation parameter, s is the distance from any point on the tool profile to the tool top, R is the shaping radius, R O R is the radius of the outer cutter disc, I is the radius of the outer cutter disc, α is the pressure angle, It is the angle from any point on the tool profile to the tool top.

[0067] Optionally, step S3 specifically includes:

[0068] Run the macro parameters and tool parameters in the bevel gear parameter design software Gems to obtain the machine tool parameters required for the master gear and the slave gear;

[0069] The machine tool parameters include: vertical tool position, horizontal tool position, horizontal wheel position, installation angle, radial tool position, tool inclination angle, tool rotation angle, vertical wheel position, installation angle, horizontal wheel position, bed position, roll ratio, angular tool position and spiral correction coefficient.

[0070] In the machine tool coordinate system, establish the machine tool kinematic chain matrix.

[0071] It should be noted that in the machine tool coordinate system, the tool position parameters include tool inclination angle, tool rotation angle, radial tool position and angular tool position. The angular tool position can also be called the initial cradle angle. The workpiece rotation angle changes with the cradle angle, and its change ratio is determined by the rolling ratio. Then, the machine tool kinematic chain matrix M can be obtained: b1 .

[0072] M b1 =M bg (φP ,X D )M gx (γ m )M xe (X B )M em (E M )M mc (-φ0+φ C ,S r )M c1 (σ,ζ0) (5)

[0073] In the formula, φ P is the workpiece rotation angle, X D is the horizontal wheel position, γ m is the installation angle, X B For beds, E M For vertical wheel position, -φ0+φ C is the rocker angle, S r is the radial tool position, σ is the tool inclination angle, and ζ0 is the tool rotation angle. bg 、M gx M xe 、M em 、M mc 、M c1 The parameter matrices (4×4) respectively represent the corresponding parameters. The specific expressions are well-known technologies and will not be elaborated or limited in the present invention.

[0074] Optionally, in this embodiment, the gear is processed by forming method, and the tooth shape modeling is directly obtained by simulating the tooth cutting process by using the tool model and the gear blank model of the gear, specifically:

[0075] According to the horizontal tool position and vertical tool position in the machine tool parameters, determine the positional relationship between the gear blank model and the tool model;

[0076] Set the tool model as the working object, and perform cutting simulation on the gear blank model through Boolean operation;

[0077] After cutting to form a tooth surface array, an accurate model of the gear is obtained.

[0078] Optionally, the main gear is machined by the generating method. The tooth shape cannot be directly obtained through the motion relationship between the tool model and the gear blank model. It is necessary to fit the tooth surface according to the coordinates of the detection points through the tooth surface file of the bevel gear design software. Specifically, the sub-steps of establishing the precise model of the main gear include:

[0079] S41, establishing the tooth surface equation of the main gear and performing discretization processing;

[0080] The tooth surface equation is the time-varying position of the cutter head in the workpiece coordinate system, where the workpiece refers to the tooth blank model of the main gear.

[0081] Knife disc F C Time-varying position F in the main gear coordinate system C1 The equation is as follows:

[0082] F C1 =M b1 (φ P ,X D ,γ m ,X B ,E M ,-φ0+φ C ,S r ,σ,ζ0)F C (6)

[0083] Based on the meshing principle, the tooth surface equation FC1 is solved for the change of the speed and normal vector relative to the workpiece, and the meshing equation is solved to obtain the relationship between the tooth surface equation and the cutter head rotation parameter. The tooth surface equation is discretized. The cross section of the gear blank model is discretized first, and the tooth surface points are constrained in the form of rotating projection points. The iterative approximation algorithm based on the surface parameter curve is used to obtain the tooth surface point coordinates of the main gear.

[0084] S42, importing the discretized tooth surface point coordinates of the main gear into CATIA software to obtain the spatial geometric relationship of the tooth surface points;

[0085] S43, through insert-create surface-mesh surface point operation, all concave tooth length lines and convex tooth length lines are set as guide lines, and all concave tooth height lines and convex tooth height lines are set as contour lines to obtain the tooth surface of the main gear;

[0086] S44, performing Boolean operation on the obtained tooth surface array of the main gear and the tooth blank model of the main gear to obtain an accurate model of the main gear.

[0087] In a method for accurately modeling the tooth surface of a quasi-hyperbolic spiral bevel gear for a passenger car drive axle provided by the present invention, the main gear (small wheel) is processed by the development method, and the slave gear (large wheel) is processed by the forming method. The tooth surface equation of the small wheel can be obtained by expressing the parallel tooth surface equation through the relative posture of the tool model and the tooth blank model (workpiece), and then the accurate tooth surface model of the small wheel is finally obtained by discrete solution of the tooth surface equation. The accurate tooth surface model of the large wheel is obtained by Boolean operation of the tooth blank model and the tool model, and then the accurate tooth surface models are arrayed respectively to obtain the final model containing the accurate tooth surface. The above method has the advantages of high efficiency and high precision.

[0088] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for accurately modeling the tooth surface of a hypoid spiral bevel gear for a passenger car drive axle, characterized in that: The steps include: S1, establish the gear blank model of the master gear and the slave gear; S2, establishing a tool model of the master gear and the slave gear; S3, building a machine tool model; S4, the master gear adopts a generating method, and the slave gear adopts a forming method, to obtain accurate models of the master gear and the slave gear respectively; The forming method is specifically: Determine the positional relationship between the tooth blank model of the slave gear and the tool model according to the horizontal tool position and the vertical tool position; Setting the tool model as a working object, and performing cutting simulation on the tooth blank model of the slave gear through Boolean operation; After cutting to form a tooth surface array, an accurate model of the slave gear is obtained; The development method is specifically as follows: S41, establishing the tooth surface equation of the main gear and performing discretization processing; S42, importing the discretized tooth surface point coordinates of the main gear into CATIA software to obtain the spatial geometric relationship of the tooth surface points; S43, through insert-create surface-mesh surface point operation, all concave tooth long lines and convex tooth long lines are set as guide lines, and all concave tooth height lines and convex tooth height lines are set as contour lines, so as to obtain the tooth surface of the main gear; S44, performing Boolean operation on the obtained tooth surface array of the main gear and the tooth blank model of the main gear to obtain an accurate model of the main gear.

2. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of the passenger car drive axle according to claim 1 is characterized in that: Step S1 is specifically as follows: S11, inputting the macro parameters of the master gear and the slave gear into the Gleason bevel gear design software Gems; S12, running the basic parameter design module of Gems software to obtain the design parameters required for establishing the gear blank models of the master gear and the slave gear; S13, creating a two-dimensional sketch in CATIA software according to the design parameters; S14, performing a rotation operation on the two-dimensional sketch to obtain the gear blank models of the master gear and the slave gear.

3. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 2, characterized in that: The macro parameters include the number of teeth, hand direction, helix angle, pressure angle, pitch circle diameter of the tooth, tooth face width, pitch circle diameter, tooth height coefficient, tooth top height coefficient, cutter disc diameter, large wheel cutter tip width and cutter tip fillet radius.

4. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 2, characterized in that: The design parameters include the number of teeth, tooth width, offset distance, axis angle, external cone distance, tooth top height, tooth root height, pitch cone offset, pitch cone angle, face cone angle, root cone angle, rotation direction and processing method.

5. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 3 is characterized in that: The method for establishing the tool model of the slave gear in step S2 is: A two-dimensional tool curve is established in CATIA software according to tool parameters; and then the two-dimensional tool curve is rotated to obtain the tool model of the slave gear.

6. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 1, characterized in that: The tool model of the main gear in step S2 is established by a tool equation, and the tool equation includes a tool point vector equation and a normal vector equation. For straight line shaping, the tool point vector equation and the normal vector equation are: For curve modification, the tool point vector equation and normal vector equation are: In the formula, F C (x, y, z) represents any point on the cutter head (x, y, z); N C (x, y, z) is the normal vector of any point (x, y, z) on the tool profile; θ is the tool rotation parameter, s is the distance from any point on the tool profile to the tool top, R is the shaping radius, R O R is the radius of the outer cutter disc, I is the radius of the outer cutter disc, α is the pressure angle, It is the angle from any point on the tool profile to the tool top.

7. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 5, characterized in that: Step S3 specifically includes: Running the macro parameters and the tool parameters in the bevel gear parameter design software Gems to obtain the machine tool parameters required for the master gear and the slave gear; In the machine tool coordinate system, establish the machine tool kinematic chain matrix.

8. The method for accurate modeling of the tooth surface of the hypoid spiral bevel gear of a passenger car drive axle according to claim 1, characterized in that: In step S41, the tooth surface equation of the main gear is solved by an iterative approximation algorithm based on a surface parameter curve.

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