Design machining method for tooth profile chamfering

Abstract

The invention discloses a designing and processing method for tooth profile chamfering, which comprises the following steps of: 1, determining the design size of the tooth profile chamfering of a workpiece; 2, determining the end face size of the tooth profile chamfering of the workpiece; 3, determining the process size of the tooth profile chamfering of the workpiece; comprise the distance E from the positioning surface to the tooth end surface and the tooth width B. The design method of the tooth profile chamfering angle parameters can ensure that the distance in the vertical direction of the chamfer is always the same as the distance in the vertical direction of the tooth side; when the tooth end allowance and the grinding allowance in the machining process are involved, the chamfering angle of the tooth profile is selected, so that a technician can conveniently calculate the chamfering machining size; and the chamfer size of the tooth profile is clearly defined and clearly marked. The consistency of design, processing and inspection states is ensured; and gear blank tolerance is controlled, and chamfer size out-of-tolerance caused by the gear blank tolerance is prevented.

Description

Technical Field

[0001] The invention belongs to the field of parts processing, and in particular relates to a design and processing method for tooth profile chamfering. Background Art

[0002] As we all know, gear chamfers can be divided into 4 parts: tooth top chamfer, tooth end chamfer, tooth profile chamfer, tooth root chamfer, such as Figure 1 As shown in the figure, the tooth top chamfer is formed during the gear hobbing process. The tooth end chamfer is formed during the fine turning process. The tooth profile chamfer and tooth root chamfer are formed during the tooth profile chamfering process. Gear tooth profile chamfering can prevent stress concentration and fatigue microcracks during operation, reduce the risk of tooth breakage during long-term use, reduce tooth end wear, and extend gear service life. This is especially true in the new energy passenger vehicle sector, where high requirements are placed on noise, vibration, and ride comfort.

[0003] There are many different methods for chamfering tooth profiles. Common methods include grinding, extruding, and milling. Milling can be further categorized as milling, hobbing, flying cutter, and rolling. The advantage of grinding is that the entire tooth profile, including the tooth root, can be chamfered, resulting in low processing costs. However, the disadvantage is that the chamfer dimensions are difficult to control and a large amount of dust is generated during processing. The advantages of extruding are high efficiency, continuity, and suitability for automated production. The disadvantage is that extrusion molding results in metal protrusions on the tooth ends and surfaces. The advantages of milling are stable chamfer dimensions, high processing efficiency, and the ability to achieve automated production. Regardless of the processing method, the chamfer dimension design requirements must be clearly defined.

[0004] Currently, there are no unified regulations for gear chamfer dimensions, both domestically and internationally. In engineering drawings of gear parts, the requirements for tooth profile chamfers are typically specified in the technical specifications, such as tooth profile chamfers of C0.3 to C0.5. Simply specifying the chamfer value fails to clearly convey the specific dimensions required for machining. Consequently, during the gear manufacturing process, technicians, testers, and quality management personnel have varying understandings of gear chamfers, leading to differing standards, inconsistent test results, and even buck-passing. Clearly marking gear chamfers to ensure consistency in the design, machining, and acceptance of gear parts is crucial. Summary of the Invention

[0005] The present invention provides a design and processing method for tooth profile chamfering, which solves the problems of chaotic tooth profile chamfering design and rough marking causing confusion in the production process and poor performance during use.

[0006] In order to solve the above problems, the technical solutions adopted by the present invention include:

[0007] A design and processing method for tooth profile chamfering, comprising:

[0008] Step 1: Determine the design size of the workpiece tooth profile chamfer:

[0009] Define the included angle between the tooth tip and the acute chamfer edge as α, the included angle between the tooth tip and the obtuse chamfer edge as δ, and the vertical distance L of the chamfer as the tooth profile chamfer parameters for judging the chamfer size; calculate the included angle α between the tooth tip and the acute chamfer edge and the included angle δ between the tooth tip and the obtuse chamfer edge based on the gear helix angle β, equations 1 and 2; and determine the vertical distance L of the chamfer;

[0010]

[0011] Step 2: Determine the size of the workpiece tooth profile chamfer end face:

[0012] The lowest point of the tooth end of the tooth profile chamfer is lower than the diameter dev of the lowest meshing starting circle of the gear meshing;

[0013] Step 3: Determine the chamfering process dimensions of the workpiece tooth profile:

[0014] The tooth end machining allowance distance T and the grinding machining allowance K in the vertical direction of the tooth side are directly added to the vertical chamfer distance L in step 1; the angle α between the tooth end and the acute chamfer edge and the angle δ between the tooth end and the obtuse chamfer edge are the same as in step 1; the lowest point of the tooth end of the tooth profile chamfer is lower than the minimum meshing starting circle diameter dev of the gear meshing;

[0015] Step 4: Control the dimensional tolerance of the gear blank according to the chamfering clamping method, including the distance E from the positioning surface to the tooth end face and the tooth width B.

[0016] Optionally, the step 1 specifically includes:

[0017] The middle section of the tooth height of a left-handed cylindrical gear was selected as the research object;

[0018] For the acute angle edge, the change in the vertical distance L of the chamfer caused by the grinding allowance K in the vertical direction of the tooth side is as follows:

[0019] ΔL=Kcosβ(tanβ+tan(α-β));

[0020] Let ΔL = K, and we can get the angle α between the end face and the acute chamfered edge;

[0021]

[0022] For obtuse edges, the change in the vertical chamfer distance L caused by the grinding allowance K in the vertical direction of the tooth side is as follows:

[0023] ΔL=Kcosβ(tan(δ-β)-tanβ);

[0024] Let ΔL = K, and we can get the angle δ between the end face and the obtuse chamfered edge;

[0025]

[0026] Optionally, the gear helix angle β is a known product parameter and is determined by the gear design parameters.

[0027] Optionally, in step 3, the tooth end machining allowance distance T directly affects the chamfer vertical distance L and is independent of the chamfer angle parameter;

[0028] The grinding allowance K in the vertical direction of the tooth side directly affects the vertical distance L of the chamfer and is related to the chamfer angle parameter.

[0029] Optionally, in the step 2, viewed from the tooth end, the lowest point of the tooth profile chamfered tooth end is lower than the gear meshing minimum meshing starting circle diameter dev, and the gear meshing minimum meshing starting circle diameter dev has been determined in the gear parameter design stage.

[0030] Optionally, in step three, the chamfering process size of the workpiece tooth profile is L+T+K.

[0031] Optionally, in step 1, L is 0.4±0.1 mm.

[0032] Optionally, in step 4, the workpiece is moved downward from the upper center to fix the workpiece, thereby performing a pressing and centering function;

[0033] The workpiece is limited by the support below, and a spring is provided under the lower center to keep the center in a floating state, which can both center the workpiece and not affect the axial limit of the support.

[0034] Control the tolerance of the distance E from the workpiece's locating surface to the tooth end face and the tooth width B.

[0035] Optionally, the tolerance of the distance E from the positioning surface of the workpiece to the tooth end face and the tooth width B is controlled to be ±0.02mm.

[0036] The advantages of the present invention are as follows:

[0037] (1) The design method of the tooth profile chamfer angle parameters can ensure that the vertical distance of the chamfer and the distance perpendicular to the tooth side are always the same;

[0038] (2) When it comes to the tooth end allowance and grinding allowance during the processing, the tooth profile chamfer angle is selected to facilitate the process personnel to calculate the chamfer processing size;

[0039] (3) The tooth profile chamfer dimensions are clearly defined and clearly marked, ensuring consistency in design, processing, and inspection.

[0040] (4) Control the tolerance of the gear blank to prevent the chamfer size from exceeding the tolerance caused by the gear blank tolerance;

[0041] (5) Provide theoretical reference for the design optimization of chamfering tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0043] Figure 1 A flow chart of the design and processing method for tooth profile chamfering of the present invention;

[0044] Figure 2 Schematic diagram of gear chamfer division;

[0045] Figure 3 Schematic diagram of the finished gear tooth profile dimensions;

[0046] Figure 4 Schematic diagram of the minimum meshing starting circle diameter of the finished gear;

[0047] Figure 5 The influence of sharp-angle edge tooth side allowance on chamfer size;

[0048] Figure 6 The influence of the side allowance of the obtuse angle edge on the chamfer size;

[0049] Figure 7 Schematic diagram of tooth profile chamfering process dimensions;

[0050] Figure 8 Schematic diagram of tooth profile chamfering clamping and controlling gear blank tolerance;

[0051] Figure 9 This is the axial dimension requirement diagram in Example 1;

[0052] Figure 10 This is a diagram showing the axial dimension requirements before chamfering in Example 1;

[0053] Figure 11 The chamfer angle and distance dimensions in Example 1;

[0054] Figure 12 is the chamfered end face size in Example 1;

[0055] Figure 13 It is the chamfering process dimension in Example 1. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0057] In the present invention, the tooth profile chamfer is shown as follows Figure 2As shown in , when the angle between the tooth tip and the tooth side is acute, the chamfer here is called an acute chamfer; when the angle between the tooth tip and the tooth side is obtuse, the chamfer here is called an obtuse chamfer. In the present invention, the unit of angle is °, and the unit of distance is mm.

[0058] Combine Figure 1-8 The design and processing method for tooth profile chamfering of the present invention comprises:

[0059] Step 1: Determine the design size of the workpiece tooth profile chamfer:

[0060] Define the included angle α between the tooth tip and the acute chamfer edge, the included angle δ between the tooth tip and the obtuse chamfer edge, and the vertical chamfer distance L as the tooth profile chamfer parameters for judging the chamfer size; calculate the included angle α between the tooth tip and the acute chamfer edge and the included angle δ between the tooth tip and the obtuse chamfer edge based on the gear helix angle β, equations 1 and 2; determine the vertical chamfer distance L; for example, L is determined by the designer and is generally 0.4±0.1mm;

[0061]

[0062] Step 2: Determine the size of the workpiece tooth profile chamfer end face:

[0063] The lowest point of the tooth end of the tooth profile chamfer is lower than the diameter dev of the lowest meshing starting circle of the gear meshing;

[0064] Step 3: Determine the chamfering process dimensions of the workpiece tooth profile:

[0065] The tooth end machining allowance distance T and the tooth side vertical grinding allowance K are directly added to the chamfer vertical distance L in step (1); the angle α between the tooth end and the acute chamfer edge and the angle δ between the tooth end and the obtuse chamfer edge are the same as those in step (1); the lowest point of the tooth end of the tooth profile chamfer is lower than the minimum meshing starting circle diameter dev of the gear meshing;

[0066] Step 4: Control the dimensional tolerance of the gear blank according to the chamfering clamping method, including the distance E from the positioning surface to the tooth end face and the tooth width B.

[0067] In the embodiment of the present disclosure, step one specifically includes:

[0068] The middle section of the tooth height of a left-handed cylindrical gear is selected as the research object; the gear helix angle β is a known parameter of the product and is determined by the gear design parameters; when the gear tooth profile is chamfered, there are two main factors that affect the chamfer size: one is the tooth end face processing; the other is the tooth side grinding.

[0069] For the acute angle edge, the change in the vertical distance L of the chamfer caused by the grinding allowance K in the vertical direction of the tooth side is as follows:

[0070] ΔL=Kcosβ(tanβ+tan(α-β));

[0071] Let ΔL = K, and we can get the angle α between the end face and the acute chamfered edge;

[0072]

[0073] For obtuse edges, the change in the vertical chamfer distance L caused by the grinding allowance K in the vertical direction of the tooth side is as follows:

[0074] ΔL=Kcosβ(tan(δ-β)-tanβ);

[0075] Let ΔL = K, and we can get the angle δ between the end face and the obtuse chamfered edge;

[0076]

[0077] In the embodiment of the present disclosure, the gear helix angle β is a known product parameter and is determined by the gear design parameters.

[0078] In the embodiment disclosed herein, in step 3, the tooth tip machining allowance distance T directly affects the vertical chamfer distance L and is independent of the chamfer angle parameters; the tooth flank vertical grinding allowance K directly affects the vertical chamfer distance L and is related to the chamfer angle parameters. The tooth tip machining allowance directly affects the vertical chamfer distance L and is independent of the chamfer angle parameters α and δ. However, the tooth flank machining allowance affects the vertical chamfer distance L and is closely related to the chamfer angle parameters α and δ.

[0079] In the embodiment of the present disclosure, in step 2, as viewed from the tooth end, the lowest point of the tooth chamfer is lower than the minimum meshing starting circle diameter (dev) of the gear meshing. The minimum meshing starting circle diameter (dev) of the gear meshing is determined during the gear parameter design stage. As viewed from the tooth end, the diameter of the lowest point of the chamfer should be lower than the minimum meshing starting circle diameter (dev) of the gear meshing. This prevents stress concentration and fatigue microcracks during gear use. The minimum meshing starting circle diameter (dev) of the gear meshing is determined during the gear parameter design stage.

[0080] In the disclosed embodiment, in step three, the workpiece tooth profile chamfer process dimensions are L+T+K. The tooth end face machining allowance T and the grinding machining allowance K in the direction perpendicular to the tooth flank are determined during the process planning phase. Based on the tooth profile chamfer parameter design method described above, these two values ​​can be directly added to the product chamfer dimension L, i.e., the tooth profile chamfer process dimensions are L+T+K. The acute and obtuse chamfer angles and the lowest point of the end face tooth profile chamfer are selected consistent with the above design method.

[0081] In the embodiment of the present disclosure, in step four, the workpiece is moved downward by the upper center to fix the workpiece, which plays a role of pressing and centering; the workpiece is limited by the support below the workpiece, and a spring is provided under the lower center to keep the center in a floating state, which can be both centering and does not affect the axial limit of the support; the tolerance of the distance E from the positioning surface to the tooth end face and the tooth width B of the workpiece is controlled. The smaller the tolerance, the more stable the chamfer size, which is generally ±0.02mm. Taking the clamping method of shaft tooth chamfering processing as an example, the workpiece is moved downward by the upper center to fix the workpiece, which plays a role of pressing and centering. The workpiece is limited by the support below the workpiece, and a spring is provided under the lower center to keep the center in a floating state, which can be both centering and does not affect the axial limit of the support. Factors affecting the chamfering processing size: the distance E from the positioning surface to the tooth end face and the tooth width B. Control the tolerance of these two dimensions of the workpiece. It can effectively prevent the chamfering processing size from being out of tolerance.

[0082] Example 1:

[0083] Table 1 Workpiece parameters

[0084]

[0085] Combine Figure 9 and 10 According to the dimensional requirements in , the helix angle of 19.4° in the gear parameters is substituted into Equation 1 and Equation 2 to obtain:

[0086] The included angle of the acute chamfered edge is α=54.7°; the included angle of the obtuse chamfered edge is δ=35.3°; and L=0.4±0.1mm;

[0087] At this time, the design dimensions of the chamfer can be obtained, and the results are as follows: Figure 11 .

[0088] According to the axial dimensions in the drawing and the axial dimensions before chamfering, it can be seen that the machining allowance on the right side of the tooth is 0.15mm and the machining allowance on the left side is 0.3mm.

[0089] According to the tooth thickness of hobbing and grinding, the single-side tooth thickness allowance is 0.07 mm. When the design angle is selected according to the present invention, the machining allowance and the single-side tooth thickness allowance can be directly added to the axial dimension of the chamfer.

[0090] At this point it is easy to get the chamfering process dimensions such as Figure 12 and 13 shown.

[0091] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A design and processing method for tooth profile chamfering, characterized in that: include: Step 1: Determine the design size of the workpiece tooth profile chamfer: Define the included angle between the tooth tip and the acute chamfer edge as α, the included angle between the tooth tip and the obtuse chamfer edge as δ, and the vertical distance L of the chamfer as the tooth profile chamfer parameters for judging the chamfer size; calculate the included angle α between the tooth tip and the acute chamfer edge and the included angle δ between the tooth tip and the obtuse chamfer edge based on the gear helix angle β, equations 1 and 2; and determine the vertical distance L of the chamfer; Step 2: Determine the size of the workpiece tooth profile chamfer end face: The lowest point of the tooth end of the tooth profile chamfer is lower than the diameter dev of the lowest meshing starting circle of the gear meshing; Step 3: Determine the chamfering process dimensions of the workpiece tooth profile: The tooth end machining allowance distance T and the grinding machining allowance K in the vertical direction of the tooth side are directly added to the vertical chamfer distance L in step 1; the angle α between the tooth end and the acute chamfer edge and the angle δ between the tooth end and the obtuse chamfer edge are the same as in step 1; the lowest point of the tooth end of the tooth profile chamfer is lower than the minimum meshing starting circle diameter dev of the gear meshing; Step 4: Control the dimensional tolerance of the gear blank according to the chamfering clamping method, including the distance E from the positioning surface to the tooth end face and the tooth width B.

2. The design and processing method for tooth profile chamfering according to claim 1, characterized in that: The step 1 specifically includes: The middle section of the tooth height of a left-handed cylindrical gear was selected as the research object; For the acute angle edge, the change in the vertical distance L of the chamfer caused by the grinding allowance K in the vertical direction of the tooth side is as follows: ΔL=Kcosβ(tanβ+tan(α-β)); Let ΔL = K, and we can get the angle α between the end face and the acute chamfered edge; For obtuse edges, the change in the vertical chamfer distance L caused by the grinding allowance K in the vertical direction of the tooth side is as follows: ΔL=Kcosβ(tan(δ-β)-tanβ); Let ΔL = K, and we can get the angle δ between the end face and the obtuse chamfered edge; 3. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: The gear helix angle β is a known product parameter and is determined by the gear design parameters.

4. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: In step 3, the tooth end machining allowance distance T directly affects the chamfer vertical distance L and has nothing to do with the chamfer angle parameter; The grinding allowance K in the vertical direction of the tooth side directly affects the vertical distance L of the chamfer and is related to the chamfer angle parameter.

5. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: In the step 2, viewed from the tooth end, the lowest point of the tooth end of the tooth profile chamfer is lower than the gear meshing lowest meshing starting circle diameter dev, which has been determined in the gear parameter design stage.

6. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: In the step three, the chamfering process size of the workpiece tooth profile is L+T+K.

7. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: In the step 1, L is set to 0.4±0.1 mm.

8. The design and processing method for tooth profile chamfering according to claim 1 or 2, characterized in that: In the fourth step, the workpiece is moved downward from the top center to fix the workpiece, which plays a role of pressing and centering; The workpiece is limited by the support below, and a spring is provided under the lower center to keep the center in a floating state, which can both center the workpiece and not affect the axial limit of the support. Control the tolerance of the distance E from the workpiece's locating surface to the tooth end face and the tooth width B.

9. The design and processing method for tooth profile chamfering according to claim 8, characterized in that: The tolerance of the distance E from the workpiece positioning surface to the tooth end face and the tooth width B is controlled to be ±0.02mm.

Images