Digital Simulation of Reducer Power Enhancement

In the design of the transmission, it was necessary to consider a large number of operating parameters in the design and determination of the size of the design, allowing the power geometry boundary and position relationship, speed ratio data and many other parameters to be determined. When determining the size of the reducer shaft, the transmitted torque, the bending stress and the lateral force appear, taking into account the stress concentration in the hazardous area accordingly, all play a decisive role in the calculation. For rolling bearing calculations, the dimensions should be included in the application's required life limits and space limits.

Today, the transmission of technical components, such as gear reducer, requires light weight, reducer structure is firm, high power density, reducer components long life. From the single-piece production of the gear unit to the large number of reducer series, it is required that the individual system components be accurately evaluated at the planning stage, and these components must be operated without trouble under different installation conditions and operating conditions. In the development phase, this type of complex system is increasingly using digital simulation method to study.

In order to identify the static, especially the dynamic limit of the relationship between the mechanical transmission technology in the establishment of a simulation model, which in modeling efforts to try to draw as much as possible the actual system. The actual calculation model of the drive system only represents an abstract concept. In addition to finding the deformation relationship and displacement in the gear meshing, a computational model was established, in particular, for the analysis of dynamic performance, which sets out the following points: Cost savings and time savings in new development or optimization by dynamic simulation.

(1) to clarify the questions raised (resonance, shaft or box breakage, noise, etc.).

Determine the best parameters related to the predetermined limit (eg, energy consumption stiffness limit rotational speed structural space, noise radiation, etc.).

In order to meet the growing market demand, in recent years, SKF has carried out a lot of software development work, which special attention to the development of both for the development of rolling bearings, but also for the system description of the model software and simulation software. One of the packages developed by SKF for complex system modeling and simulation is the Orpheus program, which is a set of modeling and simulation programs that best approximate the actual operating conditions.

With this software package, it is possible to achieve the planning tasks of analyzing the static and dynamic performance of the entire part or machine (eg gearboxes including gears, axle housing and rolling bearings).

In order to be able to provide the expertise and technical capabilities of SKF engineers to all users, a business unit that provides computing technology services for SKF customer circles in the name of "SKF Engineering Consulting Services" has been established. The focus of the service is on modeling and modeling of engineering applications and static and dynamic performance simulations. The preferred range of applications is a cylindrical gear reducer or a planetary gear unit, a compressor, a pump, a motor or an entire transmission circuit which, when summarized in the problem, in terms of defect analysis of deformation characteristics or noise and vibration performance, or in order to optimize the system, To carry out the study precisely.

218K reducer program prototype to participate in the 2003 Hannover Industrial Fair by SKF's different departments to optimize the 18K reducer program prototype (), that its design process.

The 18K reducer prototype was built on a 280-gauge gear reducer, constructed and analyzed in detail, and the center distance was reduced to 250 mm at the same speed ratio and power data. Of the components and the new power density to match, and to achieve the required system life of more than 5000h, it is necessary to re-calculate the reducer single parts. In addition to the new, higher carrying capacity of SKF bearings, that is, the average load capacity increased by 15% of the flexibility characteristics, deformation characteristics and component load digital simulation, the reducer analysis.

In the modeling, all parts of the gearbox housing are considered, the shafts are engaged with the bearings and the individual gears are engaged. The difficulty in modeling is a detailed description of the rolling bearing, taking into account the bearing in the preload, bearing clearance, temperature and other operating parameters and the occurrence of deflection. Manufacturing deviations (such as assembly or orientation errors, non-roundness of bearing fit) can be modeled in principle, but are not taken into account in the study.

The original box design can be very fast to build the three-dimensional model of the box (). The model is entered into the commercial finite element software "ANSYS * program, which is inserted into a single node (the outer bearing of the rolling bearing) description, and is connected into a box grid ().

The lattice structure is generally a lot of data, often due to the processing time is too long, not applicable to the actual analysis. Thus, in order to further handle the box structure, a smart compression technique called CMS (component modal synthesis) is used, thereby significantly reducing the number of degrees of freedom. In this method, The deformation field is described by the corresponding shape function, and the shape function should be chosen so that they satisfy the boundary condition.

With this method, the deformation can be calculated, and the vibration mode in the wide frequency range is naturally obtained. As a basic structure for further calculation, the deceleration including all the components is shown. In addition to calculating the core, the Orpheus program also provides the purpose of animating and visualizing the possibility. The deformation performance of the structure or the dynamic performance of the application can be graphically processed in this way (or), or viewed as a video presentation. The comparative observation data for the different structures or schemes can be listed and evaluated. Possible optimization measures, and their impact on the stiffness changes associated with factors such as enclosure structure, bearing selection and bearing arrangement, can be virtually modeled in a computer.

3 Summary In order to evaluate and optimize the prototype of the 18K reducer program within the scope of the 18K project, the following data are obtained: all contact stress distributions in a single rolling bearing.

One by one bearing inside and outside the seat between the tilt.

One by one in accordance with ISO281131 calculated by a single rolling bearing to modify the nominal bearing life.

The identification of vibration characteristics and possible reduction of the main characteristic noise source of the gear unit is not the object of the optimization measure.

The power of the reducer unit prototype 18K is comparable to that of the large-scale 280 reducer currently used in the industry. However, compared with the basic model, the weight is reduced by 15% to 2%, the size is reduced by 1 to 20% 10% to 13%. The large number of applications with the limited number of methods associated with the SKF program Orpheus make it possible to perform detailed analysis of the static and dynamic performance of all the transmission parts of the overall reducer system.