共查询到20条相似文献,搜索用时 7 毫秒
1.
2.
3.
4.
The aim is to study the effect of several distinct manufacturing processes, parameters and ingredients on the physical, mechanical and frictional characteristics of brake pad developed using hand lay method (sample 1), brake pad developed using hot compression method (sample 2) and commercial brake pad (sample 3). The non asbestos brake pad samples were compared with the selected commercial brake pad sample using pin on disc test set up. Results showed that friction performances of all three samples were insensitive to water and oil absorption test. Sample 2 had better mechanical properties and greater wear resistance than other two samples which are attributed to use of hot press method of manufacturing the composite and selecting the carbon-based ingredients. Sample 1 maintained high coefficient of friction even though manufactured with the help of hand lay method. Both fabricated brake pads are stable upto the temperature 220 °C without any weight loss and degradation. Brake pad surfaces showed different shape wear debris and plateaus significantly affecting the friction characteristics. Finally, the test results indicated that both fabricated brake pad samples have potential braking characteristics to be used as a brake pad material. 相似文献
5.
This work is aimed to study the tribological properties difference of potentially new designed non-commercial brake pad materials with and without asbestos under various speed and nominal contact pressure. The two fabricated non-commercial asbestos brake pad (ABP) and non-asbestos brake pad (NABP) materials were tested and compared with a selected commercial brake pad (CMBP) material using a pin-on-disc tribo-test-rig under dry contact condition. Results showed that friction coefficients for all materials were insensitive to increasing speed and pressure. NABP maintained stable frictional performance as ABP material when contact temperature elevated. Moreover, NABP proved to have greater wear resistance compared to ABP and CMBP materials. Furthermore, the SEM micrographs of brake pad surfaces showed craters which is due to disintegration of plateaus. Finally, the test results indicated that the NABP has the potential braking characteristic for a brake pad material. 相似文献
6.
制动盘对盘形制动摩擦性能的影响 总被引:3,自引:0,他引:3
在l:l惯性力矩制动试验台上研究了蠕墨铸铁制动盘和灰铸铁制动盘与所研制的合成材料闸片配副时的摩擦磨损性能。结果表明制动盘材质对摩擦性能有很大的影响:所研制的合成材料闸片与灰铸铁盘配副的摩擦副具有较小的速度、压力敏感性,较高的摩擦系数,较低的制动盘表面温度,但闸片的磨损量较大。 相似文献
7.
Worldwide, both brake lamps and tail lamps on motor vehicles are required to be red. Previous studies have not examined the effect of this confound in a complex, high-traffic scenario in a driving simulator or on visuomotor behavior. In the first experiment, drivers detected brake lamps on nine lead vehicles and lane changes on two rear vehicles in a 15 min simulated night time highway drive. A second experiment was used to examine the findings in the context of pre-attentive visual processing research. A third experiment analyzed visuomotor behavior and subjective workload during a vigilance task to further evaluate this hypothesis. For all studies, tail lamp color was manipulated, resulting in two conditions: the currently mandated red tail lamps and red brake lamps vs. yellow tail lamps and red brake lamps. Compared to current rear lighting, employing yellow tail lamps with red brake lamps reduced RT, error, subjective workload, improved performance in detecting lane changes and also changed visuomotor behavior. It is suggested that the mechanism allowing better performance is pre-attentive, parallel visual processing. 相似文献
8.
9.
10.
树脂基体作为粘结剂,对NAO刹车片的各项性能有着很大的影响,酚醛树脂已经不能满足要求,必须对酚醛树脂进行物理或化学改性。通过分析酚醛树脂的分子结构特点,指出了酚醛树脂的改性途径和方向。全面介绍了近年来常用的几种化学和物理改性酚醛树脂方法,以及对刹车片摩擦材料性能的影响。 相似文献
11.
An analysis of thermoelastic contact problem of functionally graded (FG) rotating brake disk with heat source due to contact friction is presented. Finite element method (FEM) is used. The material properties of disk are assumed to be represented by power-law distributions in the radial direction. The inner and outer surfaces considered are metal and ceramic, respectively. Pure material is considered for the brake pad. Coulomb contact friction is assumed as the heat source. It is divided into two equal parts between pad and brake disk which leads to thermal stresses. Mechanical response of FG disks are compared and verified with the known results from the literatures. The results show that the maximum value of radial displacement in mounted FG brake disk is not at outer surface. It is found that the all areas between pad and brake disk is in full-contact status when the ratio of pad thickness to brake disk thickness is 0.66. It is observed that the total strain due to thermomechanical load is negative for some parts of the disks, whereas, the thermal strains are always positive. It can be concluded that gradation index of the metal-ceramic has significant effect in the thermomechanical response of FG disks. 相似文献
12.
This paper describes research and parametric analyses of braking effectiveness and directional stability for golf cars, personal transport vehicles (PTVs) and low speed vehicles (LSVs). It is shown that current designs, which employ brakes on only the rear wheels, can lead to rollovers if the brakes are applied while traveling downhill. After summarizing the current state of existing safety standards and brake system designs, both of which appear deficient from a safety perspective, a previously developed dynamic simulation model is used to identify which parameters have the greatest influence on the vehicles’ yaw stability. The simulation results are then used to parametrically quantify which combination of these factors can lead to yaw induced rollover during hard braking. Vehicle velocity, steering input, path slope and tire friction are all identified as important parameters in determining braking stability, the effects of which on rollover propensity are presented graphically. The results further show that when vehicles are equipped with front brakes or four-wheel brakes, the probability of a yaw induced rollover is almost entirely eliminated. Furthermore, the parametric charts provided may be used as an aid in developing guidelines for golf car and PTV path design if rear brake vehicles are used. 相似文献
13.
采用半固态搅拌熔炼-液态模锻工艺制备了与Santana轿车前制动器相匹配的SiC颗粒增强铝基复合材料制动盘,对该制动盘进行了材料拉伸性能和微观结构分析,并在SCHENCK制动试验台上进行了制动性能和制动磨损试验。结果表明,复合材料的拉伸性能优于传统制动盘材料HT250铸铁;在各种制动工况条件下,复合材料制动盘对制动衬片的摩擦系数均在大众公司企业标准规定的范围之内,且较稳定;此外,复合材料制动盘质轻、耐磨,制动噪音小、温升低,运转平稳;因此,可望以其替代传统的铸铁制动盘,提高制动器的安全可靠性和服役寿命,减轻轿车悬挂系统的重量,降低油耗。 相似文献
14.
In this paper, the transient and contact analysis of functionally graded (FG) brake disk is presented. The analysis was carried out using ANSYS parametric design language (APDL). The FG brake disk is made of metal–ceramic material. The material properties vary in radial direction with the values from full-metal at the inner radius to that of full-ceramic at the outer radius. In the analysis, FG brake disk is in contact with one pure pad disk and coulomb contact friction is considered as heat source. The non-dimensional results are obtained for specific value of grading index (n = 1) by considering different material property divisions of 25, 50, 100 and 200. The results presented are for the pressure distribution, total stress, pad penetration, friction stress, heat flux and temperature during contact, for different values of contact stiffness factor, Fkn, which depends on the property gradation of FG brake disk with 200 material property divisions. The results show that the contact pressure and contact total stress increase with increasing values of Fkn, and hence it can be concluded that gradation of the metal–ceramic has significant effect in the thermomechanical response of FG brake disks. 相似文献
15.
对机车车辆在低速制动工况下转向架及制动系统发生的颤振现象进行了系统分析。通过对制动中轮对与闸瓦摩擦副特性曲线、制动系统动态特性的分析研究可知,摩擦副负特性曲线是引起制动系统颤振的根本原因,可通过加强制动器与转向架构架连接刚度的方法来抑制和消除制动系统颤振。 相似文献
16.
汽车制动器振动形式的噪声,成为目前汽车研究的一个难题.首先在理论上,对制动器的振动特性进行了研究,然后利用ANSYS/LS-DYNA软件,对某汽车盘式制动器进行了瞬态动力学分析,得出了其振动曲线.模型研究得出,制动盘和摩擦片之间的摩擦力,是引起制动器振动的一个诱导因数,减小摩擦系数可降低振动. 相似文献
17.
The present work deals with the influence of pad span on fretting fatigue behaviour of AISI 304 stainless steel. Relative
slip is one of the three primary variables influencing fretting fatigue behaviour. The relative slip can be modified by changing
the pad span and/or cyclic stress. In the present study, the effect of relative slip was studied at different cyclic stress
levels and by using fretting pads with three different pad span values (15, 20 and 30 mm). The relative slip increased with
an increase in pad span and cyclic stress. Samples tested with fretting pads having longer pad span (30 mm) exhibited longer
lives. Though the specimens tested with pads having longer pad span experienced higher frictional stress and tangential force
coefficient compared with those tested with pads having smaller pad span (15 or 20 mm), the relative slip values were larger
in the former. Due to larger relative slip values it was assumed that small cracks initiated by fretting fatigue would have
been worn away due to wear damage. Due to this the specimens tested with pads having longer pad span exhibited enhanced fretting
fatigue lives. More deformation-induced martensite formed in the samples tested with pads having longer pad span owing to
longer lives. 相似文献
18.
19.
构建了一个质量集中参数模型来研究耦合摩擦力对产生制动啸叫的影响,从理论模型复域特征值的研究可以揭示出产生啸叫噪声的本质原因。利用构建的质量集中参数模型对盘式制动片的各项特征参数进行了研究,由此推导出获得稳定频域响应的概念设计思路,对制动系统的有限元优化设计提供了很好的途径。 相似文献
20.
This field experiment takes a novel approach in applying methodologies and theories of visual search to the subject of conspicuity in automobile rear lighting. Traditional rear lighting research has not used the visual search paradigm in experimental design. It is our claim that the visual search design uniquely uncovers visual attention processes operating when drivers search the visual field that current designs fail to capture. This experiment is a validation and extension of previous simulator research on this same topic and demonstrates that detection of red automobile brake lamps will be improved if tail lamps are another color (in this test, amber) rather than the currently mandated red. Results indicate that when drivers miss brake lamp onset in low ambient light, RT and error are reduced in detecting the presence and absence of red brake lamps with multiple lead vehicles when tail lamps are not red compared to current rear lighting which mandates red tail lamps. This performance improvement is attributed to efficient visual processing that automatically segregates tail (amber) and brake (red) lamp colors into distractors and targets respectively. 相似文献