Spiral bevel gear and tooth body surface structure

Abstract

The utility model belongs to the field of gear structures, and particularly relates to a spiral bevel gear and a tooth body surface structure, the spiral bevel gear comprises a spiral bevel gear body, a tooth body is arranged on the spiral bevel gear body, one side of the tooth body is provided with a tooth surface and a tooth root, the height of a boundary of the tooth surface and the tooth root is larger than x, and x is equal to the maximum value of x when matched teeth of the tooth body are matched with the tooth body. The height of the lowest lower edge of the projection of the matched tooth on the tooth body; and the height of the boundary of the tooth surface and the tooth root is less than or equal to 0.45 time of the midpoint modulus of the tooth body.

Description

Technical Field

[0001] The utility model belongs to the field of gear structures, and particularly relates to a spiral bevel gear and a tooth body surface structure. Background Technique

[0002] The tooth body surface of a spiral bevel gear includes a tooth surface on the upper part of one side of the tooth body, a tooth root in the middle and lower part of one side of the tooth body, and a tooth bottom between the tooth roots of two tooth bodies. The strength of the tooth root itself affects the strength of the tooth body, and at the same time, it smoothly transitions between the tooth surface and the tooth bottom.

[0003] In the prior art, determining the parameters of the tooth root depends on the parameters of the tooth bottom arc. According to parameters such as the position and size of the tooth bottom circle, the "tooth root crowning parameter" is obtained, that is, when determining the outer edge structure of the tooth root to be cut during the first step of gear processing, that is, when cutting teeth, the height, angle and other parameters of the tooth root are determined. The determination method is complex. Specifically, reference can be made to paragraph 0288 and the corresponding drawings in CN107020422A, as well as claims 4, 20-22 and the corresponding content of the specification in CN103945953B.

[0004] On the other hand, for the processing of the tooth body, the processing scheme of the prior art is to first perform gear cutting and heat treatment, and then perform gear grinding. Advantages: good tooth surface consistency and good tooth surface roughness; Disadvantages: low bending fatigue strength of the tooth root; Therefore, further, shot peening is added later. After shot peening, the bending fatigue strength of the tooth root is strengthened, but there are micro-pits on the tooth surface, reducing the tooth surface roughness; Or further add a lapping process, but there are still problems of low tooth surface roughness and poor consistency. Content of the Utility Model

[0005] In order to solve the problem that it is difficult to determine the tooth root parameters, and the problems of rough tooth surface or low tooth root strength in the existing tooth body processing, the utility model provides a spiral bevel gear and a tooth body surface structure.

[0006] The purpose of the utility model is achieved in the following way: a spiral bevel gear structure includes a spiral bevel gear body 1, and a tooth body 2 is arranged on the spiral bevel gear body 1. One side of the tooth body 2 has a tooth surface 21 and a tooth root 22. The height of the dividing line between the tooth surface 21 and the tooth root 22 is greater than x, where x is the height of the lowest lower edge of the projection of the mating tooth of the tooth body 2 on the tooth body 2 when the mating tooth cooperates with the tooth body 2; The height of the dividing line between the tooth surface 21 and the tooth root 22 is less than or equal to 0.45 times the module at the midpoint of the tooth body 2.

[0007] Further, the slope angle of the tooth root 22 is greater than or equal to the slope angle of the tooth surface 21 by 2° - 5°.

[0008] Further, the surface of the tooth root 22 is a shot peened surface; the surface of the tooth surface 21 is a ground tooth surface.

[0009] A surface structure of a spiral bevel gear tooth body, comprising a spiral bevel gear body 1, on which a tooth body 2 is provided. One side of the tooth body 2 has a tooth surface 21 and a tooth root 22, and the surface of the tooth root 22 is a shot-peened surface; the surface of the tooth surface 21 is a ground tooth surface.

[0010] Compared with the prior art, in this utility model: 1. The tooth root structure is determined based on the matching tooth profile structure, reducing the complex determination process; 2. The tooth root is strengthened by shot peening, and the tooth surface is formed into a smooth plane by grinding, and the two respectively form different structures. Brief Description of the Drawings

[0011] Figure 1 is a schematic structural diagram of the spiral bevel gear in the meshing state with its matching tooth;

[0012] Figure 2 is an enlarged view of the tooth body part of the spiral bevel gear in the meshing state with its matching tooth;

[0013] Figure 3 is a side expansion view of the spiral bevel gear tooth body and a diagram of the positional relationship with the mating tooth in meshing;

[0014] Figure 4 is a schematic structural diagram for determining the height of the dividing line between the tooth surface and the tooth root;

[0015] Figure 5 is a schematic structural diagram of the steps that will appear during processing when the height of the dividing line between the tooth surface and the tooth root is relatively low;

[0016] Figure 6 is a diagram of the thermal deformation data of the test piece;

[0017] Figure 7 is a diagram of the relationship between the cutting tooth surface, the tooth root surface, and the tooth body surface;

[0018] Figure 8 is formed by Figure 7 a schematic structural diagram for forming the cutting tooth surface.

[0019] Among them, there are the spiral bevel gear body 1, the tooth body 2, the tooth surface 21, and the tooth root 22. Detailed Embodiments

[0020] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts belong to the scope of protection of the present utility model.

[0021] In the present utility model, unless otherwise clearly defined and limited, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present utility model.

[0022] As shown in the attached Figure 1-2 figures, a spiral bevel gear structure includes a spiral bevel gear body 1, and the spiral bevel gear body 1 is preferably an arc-tooth spiral bevel gear. A tooth body 2 is provided on the spiral bevel gear body 1. One side of the tooth body 2 has a tooth surface 21 and a tooth root 22. As shown in the attached Figure 3 figures, the red line is the crowning height curve, and the yellow line is the profile of the mating gear. The height of the dividing line between the tooth surface 21 and the tooth root 22 is greater than x, where x is the height of the lowest lower edge of the projection of the mating tooth of the tooth body 2 on the tooth body 2 when the mating tooth cooperates with the tooth body 2; the height of the dividing line between the tooth surface 21 and the tooth root 22 is less than or equal to 0.45 times the midpoint module of the tooth body 2.

[0023] Furthermore, the slope angle of the tooth root 22 is greater than or equal to the slope angle of the tooth surface 21 by 2° - 5°.

[0024] Preferably, during production, based on the kimos software and using the backward deduction method.

[0025] The first step: After the macroscopic parameters of the product are designed, the grinding cutting edge angle and the tip radius of the tool will be obtained. Here, an embodiment is proposed. The cutting edge angle is 24.6388°, the midpoint module is 3.7424, and the tip radius of the tool is 1 mm. At this time, the crowning height of the tooth root (i.e., the above-mentioned dividing line height) and the crowning angle of the tooth root (i.e., the above-mentioned slope) can be defined. The actual crowning height of the tooth root is as shown in Figure 3 the figures. The red line is the crowning height curve, and the yellow line is the profile of the mating gear. The red line needs to be higher than the lower yellow line without intersection. At the same time, the crowning height of the tooth root needs to be less than or equal to 0.45 times the midpoint module, that is, the crowning height of the tooth root needs to be greater than 0.9356 mm and less than or equal to 1.68 mm. Finally, the crowning height of the tooth root is selected within this range as 1.5 mm.

[0026] If the crowning height of the tooth root is too small, it is easy to cause a tooth root step after grinding, reducing the bending fatigue strength of the gear; if the crowning height of the tooth root is too large, the tooth surface contact area will decrease, reducing the actual contact ratio and affecting the NVH performance (noise, vibration, and harshness).

[0027] The root relief angle is related to ① the control level of heat treatment deformation and ② the stability of gear grinding. The selected range of the root relief angle is 2° to 5°. Here, a root relief angle of 4° is selected from it, and then the enlarged drawing of the root relief and fillet can be drawn as Figure 4 shown: The green line is the root relief height of 1.5 mm, the black line is the root profile without root relief, the red line is the root relief angle of 4°, which is obtained based on the offset angle of the intersection point of the root and the bottom of the tooth, and it is the root relief profile when the root relief height is 1.5 mm. At this time, the normal tooth thickness difference between 0° and 4° is 0.052 mm, which means that when the single-sided tooth thickness machining deviation is greater than 0.068 mm, a stress concentration will occur at the step of the tooth surface and the root fillet, as Figure 5 shown.

[0028] Step 2: After considering the uneven deformation of the tooth surface at the large end and the small end of the spiral bevel gear after heat treatment, resulting in uneven grinding at the large and small ends; the solution is to produce test pieces for heat treatment deformation, detect the law of heat treatment deformation, and compensate on the cutting tooth profile. After production according to this plan, the tooth thickness grinding at the large and small ends is uniform during gear grinding, and the root relief amount remains consistent. The heat treatment compensation value is related to each heat treatment equipment and heat treatment process. Taking the above embodiment as an example, the difference between the cutting tooth and the ground tooth surface after heat treatment deformation compensation is as Figure 6 shown.

[0029] The surface structure of the spiral bevel gear tooth body includes a spiral bevel gear body 1, a tooth body 2 is arranged on the spiral bevel gear body 1, one side of the tooth body 2 has a tooth surface 21 and a tooth root 22, and the surface of the tooth root (22) is a shot-peened surface, that is, there are pits formed by shot peening on the tooth root 22; the surface of the tooth surface (21) is a ground tooth surface, that is, the tooth surface 21 is a smooth plane formed by gear grinding.

[0030] To form the above structure, the process technical solution is the cutting - heat treatment - high - power shot peening - gear grinding process. Specifically,

[0031] Step 3: After the first two steps are completed, the setting calculation of the cutting tooth root relief parameters can be carried out. The detailed steps are as follows: ① According to the tooth thickness allowance, offset the tooth surface to obtain the cutting tooth surface position. As Figure 7 , the black line is the ground tooth surface, and the red line is the cutting tooth surface; ② Extend the ground tooth root relief contour line to intersect with the cutting tooth surface to obtain the cutting tooth root relief height. As Figure 7 shown, the lower half of the green line is the ground tooth root relief contour line, and the upper part is the extended cutting tooth root relief contour line. The height of the intersection point of the red line and the green line is the cutting tooth root relief height.

[0032] Still taking the above embodiment as an example, the angle of the grinding tooth cutting edge is 24.6388°, the radius of the tip round corner is 1 mm, the height of the root rounding of the grinding tooth is 1.5 mm, the angle of the root rounding of the grinding tooth is 4°, and the allowance of the grinding tooth is 0.12 mm. After extension according to the third step, the height of the root rounding of the cutting tooth is 3.11 mm, and the angle of the root rounding is the same as that of the grinding tooth, both being 4°.

[0033] According to the root rounding parameters after the above three steps, the use of the above process method can be satisfied. That is, the process of cutting teeth - heat treatment - shot peening - grinding teeth, and the tooth surface profile is as Figure 6 shown, the black line is the profile of the cutting gear, and the red line is the profile of the grinding gear.

[0034] Specifically, shot peening is only carried out on the tooth root, and grinding teeth is preferably carried out on the tooth surface only by a grinding wheel grinding machine.

[0035] Using the composite process implementation method described in this patent has all the advantages of the traditional processing process plan, namely ① high bending fatigue strength of the tooth root; ② low tooth surface roughness; ③ high consistency of the grinding tooth process; which is superior to the traditional process.

[0036] The process plan of this patent processing process is cutting teeth - heat treatment - high-intensity shot peening - grinding teeth. ① When cutting teeth, root rounding treatment is carried out on the tooth root, and the uneven deformation of the large and small ends caused by heat treatment is compensated; ② After heat treatment, high-intensity shot peening strengthens the tooth root; ③ Grinding teeth only grinds the tooth surface, without grinding the tooth root and the round corner; since the transition between the tooth surface and the tooth root round corner is smooth when cutting teeth, when the root rounding design is reasonable, the transition between the tooth surface and the tooth root round corner is still smooth after grinding teeth.

[0037] The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the overall concept of the present invention, several changes and improvements can still be made, and these should also be regarded as the protection scope of the present invention.

Claims

1. A spiral bevel gear structure, comprising a spiral bevel gear body (1), a tooth body (2) being arranged on the spiral bevel gear body (1), and a tooth surface (21) and a tooth root (22) being provided on one side of the tooth body (2), wherein: The height of the dividing line between the tooth surface (21) and the tooth root (22) is greater than x, where x is the height of the lowest lower edge of the projection of the matching tooth of the tooth body (2) on the tooth body (2) when the matching tooth is matched with the tooth body (2); the height of the dividing line between the tooth surface (21) and the tooth root (22) is less than or equal to 0.45 times the midpoint module of the tooth body (2); The surface of the tooth root (22) is a shot peened surface; and the surface of the tooth surface (21) is a ground tooth surface.

2. A spiral bevel gear structure according to claim 1, characterized in that: The slope angle of the tooth root (22) is greater than or equal to the slope angle of the tooth surface (21) by 2° to 5°.

3. A spiral bevel gear tooth surface structure, comprising a spiral bevel gear body (1), a tooth body (2) being arranged on the spiral bevel gear body (1), and a tooth surface (21) and a tooth root (22) being provided on one side of the tooth body (2), characterized in that: The surface of the tooth root (22) is a shot peened surface; and the surface of the tooth surface (21) is a ground tooth surface.

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