CN111441413B - Design method of excavator thrust wheel - Google Patents

Abstract

The invention discloses a design method of a thrust wheel of an excavator, which is used for guiding the reliability design of the thrust wheel so as to prolong the service life of the thrust wheel. The method comprises the steps of firstly determining the load distribution of each part of the thrust wheel, acquiring the rigidity and the strength of each part by utilizing finite element analysis, then acquiring various data capable of ensuring the use reasonability and the service life of the two key parts of the thrust wheel, namely a sliding bearing and a floating oil seal, through calculation and test, and then carrying out simulation test on the whole thrust wheel under each working condition so as to ensure the working reliability of the whole thrust wheel. The method provides effective guidance for the reliability design of the thrust wheel.

Description

Design method of excavator thrust wheel

Technical Field

The invention relates to a thrust wheel of an excavator, in particular to a design method of the thrust wheel of the excavator.

Background

The thrust wheel is used as a core part of the crawler chassis of the excavator, and the performance of the thrust wheel directly influences the reliability and the working efficiency of the whole excavator. The design of the thrust wheel is mostly carried out by adopting simulation and analogy means in China, although the strength of the thrust wheel is statically checked, the determination of dynamic load under a limit working condition is not researched, the design of key parts such as a floating oil seal and a sliding bearing is lack of standards, the technical problems of cracking, oil leakage, abnormal abrasion and the like of the thrust wheel are not thoroughly solved all the time, the design and verification of the reliability of a product are carried out by adopting an installation checking mode, the problems of long verification period, difficulty in collection of reliability data and the like exist, and the technical research for predicting the design reliability and the service life of the thrust wheel by simulating a working condition test is not carried out.

Disclosure of Invention

The invention aims to provide a design method of a thrust wheel of an excavator, which tests and checks the whole thrust wheel and key components through a simulation working condition experiment, greatly improves the reliability of the design of the thrust wheel and shortens the verification period.

In order to achieve the above object, the invention provides a design method of a thrust wheel of an excavator, wherein the thrust wheel comprises a shaft seat, a floating oil seal, a wheel body, a wheel shaft and a sliding bearing, and the design method comprises the following steps:

step 1, carrying out load analysis of a full-working-condition system through a multi-body dynamic model to obtain load distribution of each part of a thrust wheel; determining stress-strain parameters of each part by using a finite element and rigid-flexible coupling analysis technology, and providing a basis for strength and rigidity design of a product;

step 2, determining the optimal PV value of the sliding bearing by analyzing the influence of the bearing capacity and the linear speed of the sliding bearing on temperature rise, abrasion loss and failure modes;

step 3, testing the actual surface pressure of the floating oil seal through a floating oil seal surface pressure testing device, so as to generate an assembly clearance-pressure change curve; by analyzing the pressure change rule, the design rationality of the structure and the assembly clearance of the thrust wheel floating seal chamber is rapidly verified;

step 4, simulating a working condition reliability test bed through the floating oil seal, adopting axial loading and angle deviation to realize dynamic reliability test verification of the floating oil seal, and quickly verifying the design reasonability and the service life of the dynamic floating oil seal through temperature rise and abrasion loss change;

and 5, correcting the simulated load spectrum in the multi-body dynamic model by collecting the load spectrum of the thrust wheel under each working condition, then guiding the corrected load spectrum into a multi-direction variable load test bed, verifying the reliability of the thrust wheel, and further analyzing the matching of key parameters of axial clearance, assembly clearance and wear resistance.

The invention has the beneficial effects that: the invention obtains the rigidity and the strength of each part by establishing the load distribution of each part of the thrust wheel. Two important parts, the sliding bearing and the floating oil seal, are chosen, wherein a theoretical guarantee can be provided for the service life of the sliding bearing by calculating to establish the optimum PV value of the sliding bearing. The surface pressure and the dynamic reliability of the floating oil seal are verified through the test bed so as to determine the design reasonability and the service life of the floating oil seal. Through static and dynamic verification of the whole thrust wheel, professional theoretical support is provided for the design of the thrust wheel.

Drawings

FIG. 1 is a flow chart of a method of thrust wheel design;

FIG. 2 is a schematic structural view of a thrust wheel;

FIG. 3 is a view of a topological optimization of finite element of parts of the bogie wheel;

FIG. 4 is a test chart of the surface pressure of the floating oil seal;

FIG. 5 is a diagram of a simulated condition of the floating oil seal;

FIG. 6 is a graph of a bogie wheel simulation;

in the figure, 1-shaft seat, 2-floating oil seal, 3-wheel body, 4-wheel shaft and 5-sliding bearing.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

As shown in FIG. 1, the strength and rigidity data of the part in the thrust wheel are established as standards through multi-body dynamic model analysis and finite element analysis and used for guiding the design of the part. Two key parts, namely a sliding bearing and a floating oil seal, are selected, and the optimal PV value of the sliding bearing is utilized to guide the design of the sliding bearing. And obtaining a pressure change curve of the floating oil seal by using the floating oil seal experiment table, and guiding the design of the sealing reliability of the floating oil seal. And finally, various data are acquired and analyzed from the whole machine through a multi-directional variable load experiment table of the supporting wheel, a verification standard is established, and reliable guarantee is provided for the experiment of the supporting wheel under the simulated dynamic working condition.

A design method of a thrust wheel of an excavator is characterized in that the thrust wheel used in the method comprises a shaft seat 1, a floating oil seal 2, a wheel body 3, a wheel shaft 4 and a sliding bearing 5, and is shown in figure 2. The test method comprises the following steps:

step 1, establishing a model through multi-body dynamics software such as RecurDyn, carrying out full-working-condition system load analysis, obtaining load distribution of each part of the thrust wheel, selecting the thrust wheels (the thrust wheels at two ends bear larger load during excavation) at different parts of the excavator as a research object as shown in figure 3, and analyzing load change in a series of complete actions (such as excavation actions) of the excavator. And determining the stress-strain parameters of each part by utilizing a finite element and rigid-flexible coupling analysis technology, and providing a basis for designing the strength and the rigidity of each part of the thrust wheel.

And 2, analyzing the influence of the bearing capacity P and the linear speed V of the sliding bearing 5 on the temperature rise, the abrasion loss and the failure mode, and establishing the sliding bearing technology determined based on the optimal PV value. The PV value of the sliding bearing 5 is the most important influence factor of the service life of the bearing, the PV value is the product of the load P borne by the sliding bearing and the linear velocity V, and the optimal PV value is determined by calculating the product to be smaller than the limit PV value borne by the sliding bearing so as to guide the design of the sliding bearing.

And 3, testing the actual surface pressure of the floating oil seal 2 through the floating oil seal surface pressure testing device so as to generate an assembly clearance-pressure change curve, and quickly verifying the structural rationality and the assembly clearance design of the thrust wheel floating seal chamber by analyzing the pressure change rule. The floating oil seal is also called as floating seal, belongs to one of mechanical seals in dynamic seal, and has super strong sealing performance. The floating oil seal is an important part on the thrust wheel, and the thrust wheel needs to work under a severe working condition, so that water, oil and mud are prevented from seeping into the thrust wheel, and the problem is very realistic, as shown in fig. 4, the surface pressure test device of the floating oil seal is used for actually detecting the surface pressure of the floating oil seal 2, a pair of the same floating oil seals 2 are pressed into corresponding floating seal chambers, the two floating seal chambers have a relative clearance, the surface pressure equipment is provided with a pressure sensor, the expansion force of the pair of floating oil seals 2 can be detected, namely the smaller the clearance is, the larger the expansion force is, and the equipment is used for designing the optimal assembly clearance of the floating oil seals by detecting the actual pressure (expansion force).

And 4, simulating a working condition reliability test bed through the floating oil seal, adopting axial loading and angle deviation to realize dynamic reliability test verification of the floating oil seal, quickly verifying the design rationality and the service life of the dynamic floating oil seal through temperature rise and abrasion loss change, and loading a sample of the floating oil seal into the test bed according to the assembly requirement of the floating oil seal by using hydraulic pressure to ensure that the pressure of a cover meets the specified pressure range and the continuous operation is specified for a long time. As shown in fig. 5, the floating oil seal 2 is dynamically run in (rotated), the reliability of the floating oil seal under dynamic conditions is detected, the dynamic reliability of the floating oil seal is judged according to the variation of a running temperature curve, and the more gentle the temperature is, the more reliable the dynamic use of the floating oil seal is.

And 5, collecting a thrust wheel load spectrum under each working condition through various pressure sensors arranged on the excavator, correcting the simulated load spectrum in the multi-body dynamic model, then leading the simulated load spectrum into a multi-direction variable load test bed, verifying the reliability of the thrust wheel, and further analyzing the matching of key parameters of axial clearance, assembly clearance and wear resistance of the shaft. As shown in fig. 6, it is a graph of a dynamic rotation test of the thrust wheel, after the reliability of the parts on the thrust wheel is designed, the reliability of the thrust wheel in the installation state can be checked by verifying the whole thrust wheel, and it can be seen from the graph that the gentler the temperature curve is, the more reliable the thrust wheel is, because the temperature rise is the root cause of the oil leakage of the thrust wheel.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes which can be made within the knowledge of those skilled in the art without departing from the gist of the present invention are within the scope of the claims of the present invention.

Claims (1)

1. A design method of a thrust wheel of an excavator is disclosed, wherein the thrust wheel comprises a shaft seat, a floating oil seal, a wheel body, a wheel shaft and a sliding bearing, and is characterized by comprising the following steps:

step 1, carrying out all-condition system load analysis through a multi-body dynamic model to obtain the load distribution of each part of the thrust wheel; determining stress-strain parameters of each part by using a finite element and rigid-flexible coupling analysis technology, and providing a basis for strength and rigidity design of a product;

step 2, determining the optimal PV value of the sliding bearing by analyzing the influence of the bearing capacity and the linear speed of the sliding bearing on temperature rise, abrasion loss and failure modes;

step 3, testing the actual surface pressure of the floating oil seal through a floating oil seal surface pressure testing device so as to generate an assembly clearance-pressure change curve, and quickly verifying the structural reasonability and the assembly clearance design of the thrust wheel floating seal chamber through analyzing a pressure change rule;

step 4, simulating a working condition reliability test bed through the floating oil seal, adopting axial loading and angle deviation to realize dynamic reliability test verification of the floating oil seal, and quickly verifying the design rationality and the service life of the dynamic floating oil seal through temperature rise and abrasion loss change;

and 5, correcting the simulated load spectrum in the multi-body dynamic model by collecting the load spectrum of the thrust wheel under each working condition, then guiding the corrected load spectrum into a multi-direction variable load test bed, verifying the reliability of the thrust wheel, and further analyzing the matching of key parameters of axial clearance, assembly clearance and wear resistance.

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