Abstract:
This paper presents a novel grinding method that achieves tooth profile modification for cylindrical gears. By utilizing an inclined cubic boron carbide grinding disc, the proposed method enables full-tooth-width grinding and effective tooth profile modification. Vericut machining simulation verifies that the method achieves a micro-drum tooth profile, reducing meshing partial load and enhancing transmission stability. A drum shape control adjustment model is established based on the geometric relationship between the grinding trajectory and the sectional cutting plane of the gear. It is concluded that the drum shape quantity can be accurately controlled by adjusting the installation angle of the grinding disc, ensuring both accuracy and stability of the tooth profile modification.
1. Introduction
Cylindrical gears are widely employed in power transmission systems due to their reliability and efficiency. However, manufacturing and installation errors, as well as elastic deformations, often lead to uneven load distribution along the tooth width, causing issues such as meshing partial load, engagement impacts, and noise. These issues can result in localized tooth failures and reduced gear life. Tooth profile modification, particularly in the form of crowning, can help distribute the stress evenly, reduce meshing partial load, and ultimately enhance the overall performance of the gear system.
Numerous studies have been conducted to develop methods for tooth profile modification. Han et al. [1] proposed a method using high-order polynomials for topological modification on a machine tool. Wang et al. [2] used a multi-axis linkage system on a honing wheel to achieve tooth profile modification. Yu et al. [3] employed a diamond dressing wheel with the same tooth profile as the target gear for modification. Jiang et al. [4] introduced a method involving a conical grinding wheel with axial stroke and point-contact edge grinding for shaping helical gears. Yang et al. [5] established a mathematical model for tooth profile modification in form grinding based on spatial meshing principles and validated it through experiments.
Despite these advancements, traditional grinding processes for tooth profile modification often suffer from complex motions, difficulty in maintaining precision, and low efficiency. To overcome these limitations, this paper proposes a novel grinding method using an inclined cubic boron carbide grinding disc. The method is verified through Vericut simulation, and the modified gears are analyzed for meshing characteristics.
2. Principle of Grinding with Inclined Grinding Disc
2.1 Conventional Disk Grinding Principle
Traditional disk grinding methods utilize a disk-shaped grinding wheel to generate the involute tooth profile. the gear blank undergoes a generating motion (V = ω·r) while the grinding wheel rotates at an angular velocity ωT. The grinding wheel moves axially along the gear blank, resulting in discontinuous processing along the tooth width, which reduces grinding efficiency and accuracy.
When attempting tooth profile modification with this method, the grinding wheel requires additional motions, leading to complex trajectories and difficulties in controlling the modification amount.
2.2 Inclined Grinding Disc Method
To address the issues with conventional disk grinding, an inclined grinding disc method is proposed. This method employs a cubic boron carbide grinding disc installed at an angle θ. By adjusting the installation angle θ, the grinding trajectory can be controlled to achieve a conical grinding surface, thereby modifying the tooth profile into a micro-drum shape.
The grinding disc radius R can also be adjusted to suit different modification requirements. During grinding, the gear blank undergoes a generating motion, and the grinding disc rotates rapidly, forming a conical grinding surface that modifies the entire tooth width.
3. Processing Device and Simulation
The processing device for the inclined grinding disc method is modeled in SolidWorks. The device includes a large-diameter grinding disc, a dividing table, and a longitudinal slide rail. The grinding disc is inclined at an angle θ, and the dividing table and slide rail facilitate the generating motion of the gear blank.
These parameters define the specifications of the gear blank and the grinding disc used in the process. The number of teeth (Z) is 36, indicating the total number of teeth on the gear. The module (m) is 5, which determines the basic dimensions of the gear such as pitch, tooth thickness, and tooth space. The pressure angle (α) is 20°, which is a standard value for many industrial gears and affects the shape of the tooth profile. The tooth width (B) is 30 mm, indicating the width of the gear in the direction perpendicular to the axis of rotation.
The addendum coefficient (ha) and clearance coefficient (C) are used to calculate the addendum and dedendum of the gear, respectively. These coefficients are standard values and are often used to ensure compatibility with other gears in a system.