Optimization design of compound KCB gear oil pump

Optimal design is a new technology developed on the basis of the extensive application of modern computers.

It is based on the optimization principle and method of comprehensive aspects of the factors, with man-machine cooperation or "automatic exploration" way, carried out on the computer semi-automatic or automatic design, in order to select the best design scheme under the existing engineering conditions of a modern design method.

It has been proved by practice that optimal design is an effective design method to ensure the product has excellent performance, reduce the weight of the product and reduce the cost of the project.

At the same time, it can also make the designer free from a lot of tedious and repetitive calculation work, so that they have more energy to engage in creative design, and greatly improve the design efficiency.

The "optimal value" in design refers to the optimal design value that can be obtained under the influence of certain conditions (various design factors).

Optimal value is a relative concept.

It is not the same as a mathematical extremum, but can be expressed in terms of a maximum or a minimum in many cases.

To sum up, the optimization design work includes the following two parts:

(l) Transform the physical model of the design problem into a mathematical model.

The design variables should be selected, the objective function should be listed, and the constraint conditions should be given when establishing the mathematical model.

The objective function is the functional relationship between the optimal index required by the design problem and the design variables.

(2) Adopt the appropriate optimization method to solve the mathematical model.

It can be summed up as the problem of finding the extremum or optimal value of the objective function under the given condition (constraint condition).

This chapter will be based on the theoretical basis provided in the previous chapters, the theoretical displacement G = 6.0 x L0-5 m3/r, the pressure of 5 MPa.

To minimize the volume at 25 r/s, a mathematical model for optimal design of KCB gear oil pump was established, and the calculation procedure for optimal design was worked out with Delphi language. For the equation constraint, the design point represented by the design variable must be on the surface (or line) represented by Equation (5~ll).

For the inequality constraint, the geometric surface (line) represented by its limit case divides the design space into two parts: all points in one part satisfy the constraint condition Equation (5-L2) or Equation (5-13), and this part of the space is called the feasible region of the design point and is represented by 0.

The points in the feasible domain can be selected by the design variables, which are called feasible design points or feasible points for short.

All the points in the other part do not meet the constraint conditions of Equation (5-12) or Equation (5, 13). If the design point is selected in this region, the constraint conditions will be violated. It is the non-feasible region of the design, and the point in this region is called the non-feasible point.

If the design point falls on a bound boundary surface (or boundary), it is called a boundary point. The boundary point is the allowable limit design scheme.

Optimal design process, that is, to find the best advantage or the best design scheme within the feasible region.

The following constraint conditions of the compound gear pump are established.

When the gear is processed by the model method, sometimes the top of the cutter is cut into the root of the gear tooth, so the tooth root is cut off a part of the tooth profile. This phenomenon is called the root cutting of the gear tooth.

In the mechanical principle, the cause of root cutting of gear is described in detail. Serious root cutting will affect the strength of gear teeth and the stability of transmission.

But because the gear pair in the gear pump is not a simple transmission pair, it is mainly to make the sealing volume continuously change to transport the liquid with pressure, so this book is designed by allowing slight root cut, in order to reduce the center distance and the volume of the gear pump, and can appropriately reduce the weight coefficient, is conducive to reducing the impact of trapped oil.

Nowadays, many pump manufacturers are optimizing the design to improve the quality of pumps.