Gear grinding processing technology and all aspects of gear grinding machine improvement

Gear grinding processing technology and all aspects of gear grinding machine improvement

Gears grinding Process have the advantages of low transmission noise, high transmission efficiency and long service life. Gear grinding was once considered an expensive means of machining gears used in aerospace or other high-tech fields. But now, the concept has changed: the efficiency of the gear grinding machine has increased, the grinding wheel performance has also been better, and the high cost has been greatly reduced. As a result, gear grinding has begun to be applied in gear processing on a large scale, such as the manufacture of automobile and motorcycle gears, and has reached a level of general application. In fact, all Tier 1 automotive gear suppliers generally have gear grinding machines in order to remain competitive. The automotive industry will gradually become the largest growth market for hard tooth surface machining in the next 2 to 5 years. Many gearboxes use ground gears for better control of transmission backlash and noise, as grinding removes heat-treating distortion. The gear grinding process has basically matured and is growing rapidly in the entire gear industry.

Advances in gear grinding machines

Today's gear grinding machines are much more efficient than the same type of machines of a decade ago. This comes from a series of major improvements:

1 Airborne measurements

Many gear grinding machines are made more accurate by being equipped with on-board measurement systems. Due to the use of on-machine measurement, it is not necessary to remove the gear from the workbench and send it to other places for testing, which avoids secondary installation errors during reprocessing. During processing, the gear is initially analyzed by the airborne measurement system, and then the measured parameters are compared with the theoretical design parameters to obtain the required correction. and measurement. This cycle is repeated until the required accuracy is achieved. Integrated on-board measurement and on-board correction systems make modern gear grinding machines more efficient.

In China, for example, the YK75100 profile grinding wheel gear grinding machine of Qinchuan Development Co., Ltd. is equipped with the CEP 1000 top-mounted gear measurement system of Chengdu Tool Research Institute. and control also need to be done manually). However, as far as the overall domestic level is concerned, the precision of processing and measurement needs to be further improved.

2 Direct drive motor

In recent years, there has been an increase in the use of compact direct-drive motors for grinding wheel spindles and geared workpiece spindles. Direct drive spindle avoids drive chain errors. Therefore, the use of a direct drive motor in the "grinding wheel-grinding gear" cycle, coupled with better grinding wheel and multi-axis linkage control, can eliminate high-frequency errors and harmful vibrations from cutting lines, eccentric geometry, gear operating noise .

3 Automation

The term "automation" is increasingly used in gear grinding, especially in flow production, including workpiece installation, tool change, and inventory sorting that is synchronized with the workpiece flow. Automation eliminates machine idling time and helps reduce wait time between operations. nextpage

4 Gear grinding software

Windows-based software is as widely used in today's gear grinding machines as it is for personal computers (eg Windows-based design systems and CNC systems). Previously, it was only possible to draw on paper. Now, the design plus correction software package combining the graphical interface and algorithm software can program the design of gear geometry and simulate local manufacturing.

The high-precision closed-loop control between the drive, the ball screw and the position sensor is realized by the application of software. Many new-generation gear grinding machine components are equipped with position sensors that are separate from the drive unit, resulting in greater accuracy and thermal stability. Absolute displacement sensor and absolute coding technology ensure the high-speed transmission of feedback data and the stability of machine tool transmission under the premise of high positioning accuracy.

5 Machine tool shape

Today’s gear grinders are smaller and take up less space, which allows manufacturers to make better use of the limited production area to “create” more usable space without having to spend money on the “bricks and cements” of expanding the plant ”, but used to purchase equipment.

6 New material grinding wheel

Advanced vitrified bond wheels and electroplated cubic boron nitride (CBN) wheels have the same high productivity. Due to the use of new materials in the "mixed particle" type composition and the advancement of bonding processes, the toughness, shape accuracy retention, material removal force and durability of vitrified bonded grinding wheels have been improved. These excellent properties are derived from the high performance particle structure and increased porosity. At the same time, the good particle structure reduces the grinding pressure and reduces the grinding temperature.

Now, the choice between electroplated CBN and vitrified wheels is made difficult by new cold-grinding ceramic grits that use a high-pressure coolant system. However, electroplated CBN grinding wheels are simpler to operate than vitrified bond grinding wheels, have shorter installation time, and require less technical ability of the operator, providing a more feasible low-cost option than CBN abrasive vitrified bond grinding wheels.

The American company Reishauer tested these ceramic grinding wheels with their "cold grinding" process and concluded that: ①max's new alumina abrasive and ceramic abrasive wheels can produce the same or less pressure as CBN abrasive vitrified abrasive wheels. ②Contrary to expectations, ceramic grinding wheels are more efficient and durable than CBN grinding wheels. ③Different from electroplated CBN grinding wheels, ceramic grinding wheels can be sharpened on a gear grinding machine, while electroplated CBN grinding wheels must be returned to the original factory for grinding.

Ceramic grinding wheel has a high cutting speed (such as 60m/s), so it is suitable for mass production of gears. This wheel has a longer lifespan than previous wheels such as alumina wheels. The new grinding wheel technology is more used in the worm grinding wheel for grinding gears of 200mm and below with a large output.

7. Reduction of grinding costs

Today, the cost of gear grinding has dropped sharply for many reasons, such as cost-effective models based on modular design, numerical control systems, and streamlined production. Even gear grinding machines that integrate all of the aforementioned advanced technologies are cheaper than previous models. Large-scale production has shortened the single-piece production cycle by 50% to 70% compared with the previous one, and the cost of consumables (grinding wheels and diamond correctors, etc.) has also been greatly reduced.