จำนวน Repository ( 164 )

การศึกษาพฤติกรรมการถ่ายโอนความร้อนในระบบเบรกเพื่อกำหนดค่าการนำความร้อนของผ้าเบรกที่เหมาะสม
การศึกษาพฤติกรรมการถ่ายโอนความร้อนในระบบเบรกเพื่อกำหนดค่าการนำความร้อนของผ้าเบรกที่เหมาะสม

Brake pad is a one of products that plays a role in the automotive parts industry and directly affects safety. Therefore there are many designs of brake pads for product development. This research aims to study the thermal conductivity of brake pads and define the thermal conductivity that appropriate to brake pads and also solve the problem of deterioration of braking automotive parts. To achieve this the 3 different ingredient brake pads from Compact International (1994) Co. Ltd. are studied in terms of the heat transfer behavior. The experimental work was set by simulating a brake on the single dynamometer at the braking speed of 50 100 and 130 km/h. As a results the significant parameters are copper and fillers respectively. It affects the heat transfer behavior by means of applying heat from the contact area between the brake pad and the brake disc to the caliper This knowledge will be used in the design of brake pad ingredients to determine the appropriate conductivity of the brake pads.

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การการศึกษาพฤติกรรมค่าความจุความร้อนของวัสดุความเสียดทาน
การการศึกษาพฤติกรรมค่าความจุความร้อนของวัสดุความเสียดทาน

Nowadays one of the automotive engineering is conductivity of brake pads playing a role in friction coefficient which means safety of customer. Thus thermal properties have been improved using composited materials. This project aims to study the heat capacity behavior of 3 different brake pads which are supported by the company Compact International (1994) Ltd. For experimental works temperature based on brake condition was simulated from 05 to 003°C at 5 MPa of pressure. By standard JIS D4413 testing condition of pressure was referred. The heat capacity values of brake pads are calculated under the temperature conditions. As a result of testing brake pad made of copper or high metal powders result in relatively low heat capacity. On the other hand brake pads containing fiber and a large amount of fillers result in an increased heat capacity and stability in various temperature conditions. The heat capacity varied according to the operating temperature. In addition the lubricant contained in the brake pads affects the higher heat capacity and stability at various temperatures.

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การศึกษาและวิเคราะห์อิทธิพลของธาตุเจือโลหะเงิน ทอง ทองแดง สังกะสี และดีบุก ที่มีผลต่อสมบัติ                       ทางกล และโครงสร้างจุลภาค (ความแตกต่างของระดับสี) และพฤติกรรมความต้านกันหมองของทองขาวเจือต่ำ 8k
การศึกษาและวิเคราะห์อิทธิพลของธาตุเจือโลหะเงิน ทอง ทองแดง สังกะสี และดีบุก ที่มีผลต่อสมบัติ ทางกล และโครงสร้างจุลภาค (ความแตกต่างของระดับสี) และพฤติกรรมความต้านกันหมองของทองขาวเจือต่ำ 8k

This Research is a Development of 8k White Gold low Alloy Metal Components for Jewelry Pieces. By Study and Analyze the Influence of Silver Alloy Gold Alloy Bronze Alloy Zinc Alloy and Tin Alloy. Which Affect Microstructure and Mechanical Properties. (The Different of Color Scales) And Resistance Behavior of Lowered 8k White Gold Alloy in Varies Ratio. The Results Showed that Tests and Analysis to Find the Quantities of Elements has found out that Chemical Components of 8k White Gold Low Alloy Metal had a Little Different Quantities when Compared Between Before and After Centrifugal Casting Process. The Tests and Analysis Results of Mechanical Properties of Test Pieces Showed that the Hardness and Tensile Strength of 8k White Gold Low Alloy Metal with Mixture of 33.33%Au+50.67%Ag+10%Cu+5%Zn+1%Sn had Minimum Ultimate Tensile Strength Equal 0.54 kN/mm2 Minimum Elongation Percentage of 55% and Maximum Hardness of 137.0 HV. The Test Results also Show that the Mechanical Properties of the Material are Brittle Material. When Perform a Forming Process the Pieces will be Easily Broken which was Meant that the Forming Process would be Difficult. But The Color Level of the Test Pieces at this Composite Ratio had the Best Metal Color Level. The Brightness L * = 74.87 was a * = -0.89 b * = 13.74 and the Value of ΔE with the Lowest Color Difference Level of 1.35. Compared to other Varies Ratio. It Showed that 8k White Gold Low Alloy Metal Test Pieces were Very Green and Came out Slightly Yellow Compared to the Blue Line that Approached the Standard Line. These Properties were the Physical Properties Required in 8k White Gold Low Alloy Metal Jewelry Pieces Production. Also there were the Results of 8k White Gold Low Alloy Metal in Two Formulas 8k 33.33%Au+50.67%Ag +8%Cu+7%Zn+1%Sn 33.33%Au+50.67%Ag+8%Cu+8%Zn+0%Sn. These Formulas had Tensile Strength in the Range of 1.10 0.60 kN /mm2 Elongation Percentage in the Range of 70 61% and Hardness of 115.6 123.3HV Respectively. The Results of the Mechanical Properties Test of the Test Pieces Showed that 8k White Gold Low Alloy Metal 33.33% Au+50.67%Ag+8%Cu+7%Zn+1%Sn has Similar Tensile Strength but Maximum Elongation Percentage of 70% and Minimum Hardness of 115.6HV. Which was Suitable for Forming Because of good Ductility and Stretchness Properties (Ductile Material). Forming would be Easy. These were Good Mechanical Properties for Forming Precious Metals.

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การศึกษาพฤติกรรมค่าการนำความร้อนแบบไม่เชิงเส้นของวัสดุความเสียดทาน
การศึกษาพฤติกรรมค่าการนำความร้อนแบบไม่เชิงเส้นของวัสดุความเสียดทาน

Nowadays one of the automotive engineering is conductivity of brake pads playing a role in friction coefficient which means safety of customer. Thus thermal properties have been improved using composited materials. This project aims to study the conductivity behavior of 3 different brake pads which are supported by the company Compact International (1994) Ltd. For experimental works temperature based on brake condition was simulated from 200 to 400°C and cooled down from 400 to 200°C at 1 5 and 8 MPa of pressure respectively. By standard JIS D4413 testing condition of pressure was referred. The non-linear of conductivity value are calculated from the temperature under steady state condition. As a result of testing there are several of parameters effecting on the non-linear conductivity value. The brake pad that is a mix of high-fiber affects the fluctuation of thermal conductivity. At the same time lubricant in the brake pad cause the stability of conductivity value in different temperature range at the same pressure. On the other hand the brake pad mixed hi-copper inspires the narrow range of conductivity value in different pressures at the same temperature. Moreover the conductivity value as a mention is inversely proportion with the coefficient of kinetic friction.

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การศึกษาพฤติกรรมการถ่ายโอนความร้อน และการสั่นสะเทือนของจานเบรกแบบตรง/แบบกลับที่ส่งผลกระทบต่อความสามารถการเบรก
การศึกษาพฤติกรรมการถ่ายโอนความร้อน และการสั่นสะเทือนของจานเบรกแบบตรง/แบบกลับที่ส่งผลกระทบต่อความสามารถการเบรก

The purposes of this study were to investigate the heat transfer and the vibration characteristics caused by front and back vented brake disc which had physically different shapes affecting braking distance. In accordance with the theory of heat transfer the heat transfer rates of two types of brake disc were different and played an important role in the deformation during usage. The single dynamometer was conducted to the experimental work as an engineering tool with boundary conditions according to JASO C406 standard. One degree of freedom (DOF) acceleration signals on the brake caliper were analyzed. The results obviously discovered that the back vented brake disc was able to reduce the vibration up to 43.5% comparing to the front vented brake disc in case of the braking temperature 200C initial breaking speed 50 km/h and the hydraulic pressure of 4 MPa. Besides the hydraulic pressure at 4 MPa generated the maximum vibration. Furthermore the initial braking speed and the braking temperature were also the important factors. Regarding braking distance results the results of the experimental work obviously discovered that the back vented brake disc created braking distance shorter than front vented brake disc. Besides there were important factors as braking temperature hydraulic pressure and initial speed of braking. Especially the high braking temperature caused an increase of deceleration and a decrease of braking distance. Moreover the high hydraulic pressure produced a deduction of braking distance and an increase of deceleration. Finally the initial speed of braking directly varied to the braking distance

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