Tractor rubber vibration damping handle style design and performance analysis

 

    (College of Mechanical and Electrical Engineering, Zhejiang University, Hangzhou, 310014)

 

Abstract tractor handlebar vibration source characteristics in the analysis, based on the 1154 for the isolation of natural rubber element designed a new type of rubber vibration damping handle, the handle has a simple structure, stable, easy to install use and reliable. Peasants-5 type tractor in the experimental results show that the handle effectively reduces the vibration transmissibility in the three most intense vibration in the axial direction of the maximum acceleration and the weighted acceleration were reduced by 54.8% and 55.8 %. Three axial joint accelerations decreased 44.1%, while the incidence rate of 30% of occupational vibration when the vibration disease before the extended period allowed by the vibration 126.4%, with a significant damping effect.

 

Keywords: tractor; isolation; handle

 

CLC: TB535

 

    Tractor is used in a large area of ​​rural farming machinery and power sources, especially in China, to maintain a huge amount of the large number of pilots. According to statistics, since the long-term operation of tractor, the driver due to vibration handlebar vibration causes a high incidence of the disease. Therefore, reducing the tractor vibration level, to improve working conditions for operating personnel at home and abroad has become a consistent emphasis on the agricultural machinery industry research topic. Italy Guarn-teri and Ragni, who has studied the small farm handlebar vibration transmission mechanism 11-2], Japan's large black and Danchuan Wen Ching Wu et al. Studied on the handlebars to add weight to reduce hand and Tsui Nepal The vibration method '31; in the country, Su Qingzu and others through local modification armrest frame structure parameters to improve the vibration characteristics of hand '43; Chenxin Fu and Hu Yimin declination on the flywheel balanced 's]. Each of the above methods, reducing hand handlebar vibration have some effect, but there is difficulty in conversion, complex structure, highly technical shortcomings. This paper presents a vibration-damping rubber isolator handle, the handle vibration effect is good, and has a simple, practical, easy installation advantages.

 

A rubber vibration damping handle design style

 

1.1 About damping solution

 

    General damping method are the following:

 

    (1) to prevent resonance. The method by changing the vibration frequency of the system or changing the frequency of the vibration system to reduce disturbances on the vibration response of the handle, but need to do a lot of modifications on the tractor structure, easy to implement. (2) to reduce disturbance. The method to reduce vibration excitation by reducing the vibration at the handles, but the diesel engine piston and connecting rod reciprocating inertia force generated by imbalance can not be completely eliminated, and therefore the actual damping effect is limited.

 

    (3) adopt measures to isolate the transmission of vibration isolation. Vibration at the handles tractor engine vibration source is mainly incentive and road roughness caused by road excitation, these two incentives through the chassis, frame rails, etc. spread handlebar, so if the armrest bracket connecting the appropriate shock absorber, can make the pass hand to the vibration significantly weakened, this method has a simple structure, easy to install in existing tractor advantages. In this paper, the above method (3) the mechanism design rubber isolator type

 

Vibration handle.

 

1.2 rubber vibration damping handle style design requirements

 

    Rubber vibration damping handle style basic design requirements are:

 

    (1) has good damping properties. Handlebar vibration isolation device should be rubber vibration energy consumption and spread and weaken the ability of structure-borne vibration;

 

    (2) has a good operation of tropism. Vibration handle handrail holder shall have sufficient rigidity, does not affect the operation of the tractor performance, especially at high speeds and in case of emergency, requiring large enough to withstand bending and torque;

 

    (3) simple structure and easy to install. Vibration handle should not change the basic structure of the original frame rails, and has a low cost, easy to install and convenient features, ease of application;

 

    (4) securely installed, strength, long life, safe and reliable.

 

1.3 Isolation material selection

 

    Vibration damping vibration-damping handle should be used in good performance, stable performance, ease of manufacture, low cost, good adhesion to metal, large load capacity per unit area and a long service life of the material. A variety of applications from the vehicle engineering practice, the rubber material can be effectively reduced from the engine vibration excitation, using its damping characteristics, the peak amplitude of the vibration can be eliminated, so that more uniform and reduce the impact vibration. Therefore, the choice has good overall physical and mechanical properties and can be firmly bonded with the metal material 1154 as a natural rubber vibration material, Shore hardness of 60.

 

1.4 rubber vibration damping handle style structure and working principle

 

    Vibration-damping rubber isolator handle is made of rubber vibration isolation system and handrail frame composition, front armrest between the frame and rear frame rails connected by a rubber vibration isolation devices. Structure of the rubber vibration isolator shown in Figure 1. 1154 will be strong adhesive natural rubber glued together with internal and external metal casing, this structure not only guarantees the handrail frame stiffness requirements, but also makes vibration isolation system is easy to install. In use, the engine and the surface of the vibration excitation have to be transmitted by the vibration device in to the rear end of the driver to grasp the handrail frame, the rubber phase transition and molecular diffusion can effectively consume and extended vibration energy, so that transient vibration rapid decay, reducing vibration amplitude.

 

    Since vibrations are transmitted frame rails gradually enlarge, therefore, does not affect the operation of the shift lever and ease of installation, under the premise isolation component parts should be installed near the engine. Experiments handlebar vibration damping rubber isolator type component installation parts shown in Figure 2.

 

2 Vibration Test and Analysis of Results

 

2.1 Analysis of vibration source tractor

 

    Tractor using water-cooled single-cylinder diesel engine compression ignition

 

2.2 Test Methods

 

    In view of the vibration caused by uneven road painting the total station only 20% of the vibration at the handles, the pilot study to observe the handle of the engine vibration caused by unbalanced inertia force based vibration isolation effect. To simplify the test, one of the workers and peasants, 5 type tractor parked on a flat concrete floor test, the driver holding the handle simulated working conditions, the engine speed is 3000r/min, because in this hand to deliver speeds of maximum vibration. According to IS05349-1986 (E) provided by the vibration of the hand coordinate system, shown in Figure 3. Authors made a sensor bracket mounted on the handlebar to ensure three mutually perpendicular axis. Using CA - YD127 accelerometer measured acceleration signals taken by YE5938 dynamic data acquisition acquisition and recording, and then through the RS232-C serial interface to the computer for data analysis, and use the printer output.

 

    For comparison, the first anti-vibration device not added when measuring vibration acceleration of the handle. Then, install the anti-vibration device, and measured under the same experimental conditions handlebar vibration acceleration. To reduce the random error, each time taking the average of five tests spectral analysis of frequency band is 0 ~ 2000Hz. Test points shown in Figure 2, the test results in time domain waveforms

 

And the amplitude spectrum shown in Figure 4 and Figure 5.

 

    Xh direction in, for example, from Figure 4 and Figure 5, plus vibration loading Z3 conclusions

 

    (1) from the tractor transmitted to the driver handle arm vibration mainly from diesel engines unbalanced periodic vibrations and inertia force generated as a random uneven surface caused by vibration, the former 80% of the total energy of the vibration, the vibration energy basically concentrated in the 0-200Hz band, the maximum amplitude occurred in Xh direction.

 

(2) the amplitude of vibration at the handles with the arm rest a distance from the engine increases, vibration isolation device should be installed close to the engine.

 

(3) vibration-damping rubber isolator components increase grip with rubber vibration damping and isolation transmissibility, damping effect is obvious. When the incidence of C a 30% allowable vibration disease before the occurrence of vibration period extended by 126.4%.

 

    (4) rubber isolator type vibration damping handle simple structure, stable performance, easy installation, safe and reliable.