The gear meshing mode of industrial gear pump is the core factor affecting the medium conveying efficiency, and the size of its meshing clearance is directly related to the amount of volume loss. When the gear meshing clearance is too small, the friction resistance between the tooth surfaces increases, which will consume more power and lead to a decrease in effective output efficiency; when the clearance is too large, the medium in the high-pressure chamber will leak through the clearance to the low-pressure chamber, causing volume loss. Especially when conveying high-viscosity media, this leakage will be more obvious, directly reducing the medium conveying volume per unit time. Therefore, a reasonable meshing clearance needs to find a balance between reducing leakage and reducing friction to ensure a higher conveying efficiency.
The effect of gear meshing accuracy on efficiency is reflected in the smoothness of power transmission. Gears with high-precision meshing have high tooth profile fit, small impact and vibration during operation, and can more efficiently convert the power of the motor into the energy of the conveying medium. If the meshing accuracy is insufficient, there will be misalignment or jamming between the tooth surfaces, which will not only cause additional energy loss, but also cause unstable medium conveying volume due to instantaneous pressure fluctuations. Long-term low-precision meshing will also aggravate tooth surface wear, further deteriorate the meshing state, and form a vicious cycle of continuous decline in efficiency.
Different gear meshing forms adapt to the conveying needs of different media, which in turn affects the efficiency. When spur gears are meshed, the tooth surface contact line is parallel to the axis. A large radial force will be generated during the meshing process, resulting in increased vibration of the gear pump body and increased energy loss. This effect is more significant especially when running at high speeds. It is suitable for conveying media with low viscosity. When helical gears are meshed, the tooth surface contact line is inclined, the meshing process is smoother, the radial force is small, and it can maintain stable operation at higher speeds. It is more efficient when conveying high-viscosity media because the smooth meshing reduces the energy loss caused by turbulence.
The overlap coefficient of gear meshing has a direct impact on the continuity of conveying, which is then related to efficiency. In the meshing method with a large overlap coefficient, there are always more than two pairs of teeth meshing at the same time during the transmission process, which can effectively reduce the pulsation of the medium conveying and make the flow more stable. This continuity avoids the pressure loss caused by flow fluctuations, makes the power output more uniform, and reduces unnecessary energy consumption. However, the meshing method with a small overlap coefficient is prone to instantaneous flow interruption, large pressure fluctuations, and more energy is consumed to maintain stable output, and the overall efficiency is relatively low.
The lubrication state during the meshing process depends on the reasonable meshing method. Insufficient lubrication will significantly reduce efficiency. When the gears are meshed in an appropriate manner, a stable oil film can be formed between the tooth surfaces, reducing the friction and wear caused by direct metal contact and reducing friction loss. If the meshing method is improper, the oil film is easily destroyed, and dry friction or semi-dry friction occurs on the tooth surface, which will not only increase power consumption, but also cause changes in the properties of the medium due to overheating, affecting the conveying efficiency. Especially when conveying media without lubricants, the influence of the meshing method on the lubrication state is more critical.
The symmetry of gear meshing will affect the force balance of the gear pump body and indirectly affect the efficiency. For symmetrically meshed gears, the axial forces generated during operation can offset each other, the gear pump shaft is evenly loaded, the bearing wears slowly, and can maintain a stable operating state for a long time, ensuring that the efficiency does not drop significantly with the use time. For asymmetrically meshed gears, the axial force cannot be balanced, which will cause the bearing to bear additional unilateral pressure, accelerate wear and increase the gap, resulting in increased medium leakage, gradually reduced efficiency, and more frequent maintenance is required to maintain performance.
The influence of the meshing method on the flow path of the medium will also change the conveying efficiency. The size and shape of the seal cavity formed when the gears mesh determine the flow speed and resistance of the medium in the gear pump. The optimized meshing method allows the medium to flow smoothly in the seal cavity, reducing eddy currents and impacts, and reducing energy losses caused by flow resistance. If the meshing method causes the seal cavity to have an irregular shape, the medium will generate violent turbulence in the cavity, which will not only consume energy, but may also cause damage to the seal due to excessive local pressure, further affecting efficiency and equipment life.
