Mechanical department, Pune University, Pune, India

Transcription

1 To Check Tir Of Gears Using Hydro-Pneumatic Intensifier After Heat Treatment Rohan Ghorpade 1, Rahul Parikh 2, Parag Gholawde 3, Amol Pangare 4, Mr. Mukesh Chaudhari 5 1,2,3,4,5 (student, student, student, student, guide), K.J.College of Engineering, Mechanical department, Pune University, Pune, India Abstract: Heat treatment plays a major role in manufacturing as well as performance of gears. Heat treatment being the crucial process cannot be omitted. Hence heat treatment plays a vital role. Gear goes through various processes in the heat treatment department which causes warpage in the gear which needs to be detected in advance further working on gear to avoid loss in time, money and eventually productivity loss. This warpage causes various geometrical errors in circularity, roundness and phase run out etc. These errors normally tend to go undetected as there is no provision for testing of these gears. Therefore to develop a best technique testing equipment as a pro-active measure to avoid these rejections. This paper shows a solution to the above problems by designing a semi-automatic gear clamping and testing fixture. Initially the gear is placed concentric with the expansion sleeve. The Hydro - Pneumatic intensifier supplies the hydraulic compressed fluid to the Expansion sleeve. Hence, the expansion sleeve expands and engages with the gear. This gear is rotated manually and the dial indicator placed above it is used to check the dimensions of the gear such as concentricity, roundness, surface finish, pitch circle diameter etc. Two different expanding sleeves have been designed for two various gears. The design of fixture is shown by 3D modeling and the gears to be clamped in 2D. The design was checked and validated for safety under the action of forces. Keywords: dial indicator, expanding sleeve, fixture design, gears. Introduction The rapid development of heavy industries such as vehicle, shipbuilding and aircraft industries require advanced application of gear technology [1]. Hence, it is very necessary for the gear to be defect free. Here, we are dealing only with the production of crank shaft spur gears. Gear defects are a major reason for poor quality and of embarrassment to manufacturers, hence, to reduce error on identifying gear defects requires more accurate and automotive process.[2] Total Indicator Run-out is the difference among the maximum and minimum measurements, that is, readings of an indicator, on the planar, cylindrical, or contoured surface of a part, showing its amount of departure from flatness, roundness (circularity), cylindricity, concentricity with other cylindrical features, or alike conditions. The TIR of a conveyor idler roll is measured by rotating its shell while its shaft is held stationary and reading measurements from a dial indicator or some type of displacement transducer that is resting on the revolving shell. [3] The indicator traditionally would be a dial indicator, today dial-type and digital indicators coexist. The amount of misalignment is measured accurately using dial test indicator [4]. Here we check the TIR of gears using a dial indicator which is static and the gear is moved to check the various dimensions. These gears are held in a fixture assembly operating on Hydro- Pneumatic intensifier. A way to guarantee constant air pressure is to install a hydro-pneumatic system, depending on the pressure level and pipeline operation. [5] The hydraulic and pneumatic combination saves lot of bulkiness to the apparatus and makes it compact for use. Moreover, it works efficiently with available pressure and eliminates any further arrangement of pumps, compressors etc. The Total Indicator Reading (T.I.R) is checked with the help of simple dial gauge which is mounted on the whole assembly. The fixture is designed to check the T.I.R. as deviation in reading will indicate that any one or more geometrical parameters of gear are not in conformation with the required ones. The fixture is basically designed to recognize these geometrical distortions of the gear caused due to heat treatment. Main criteria of the fixture for holding variety of work piece geometry within acceptable accuracy and stability.[6] The purpose of heat treatment is to soften the metal, to change the grain size, to modify the structure of the material and relive the stress set up in the material[7]. Hence, the gears are heat treated. Heat treatment of gears after their manufacturing resulted in scaling. This scaling is quite unavoidable in spite of various measures taken by the organization. There is no provision to check this distortion due to heat treatment and several geometrical errors it caused. Page 95

2 METHODOLOGY The gears are placed concentric to the central axes of the system. Here, two different types of gears having weights 1.5 kg and 3 kg (approx.) are used to check for their TIR. The gear fits into the expansion sleeve. There are two different clamping devices for the two different gears. The figure shows the two different gears and the expanding sleeve. Fig 1: Gears to be inspected. Fig 2: Expanding Sleeve 1&2 The expanding sleeve is held in its position using the locator. There are two different types of locators used according to the type of gear to be checked. The locatorshave an internal cavity through which the pressurized oil flows to the expanding sleeve. The figure shows the locators used. The locators are made in a way that easy and quick change of the locator along with expanding sleeve is possible. Page 96

3 Fig 3: Locator 1&2 The bottom locator is connected to the spindle. The spindle is hollow which allows for the flow of compressed oil through. The bottom side of the spindle is connected to the Hydro - Pneumatic intensifier, hence, the spindle acts as a connecting link between the locator and the Hydro - Pneumatic intensifier. The spindle along with the locator can be rotated manually in order to rotate the gear for checking. The figure shows the spindle. Fig 4: Spindle The spindle is supplied with pressurized hydraulic oil using a hydro-pneumatic intensifier. The intensifier uses the air system pressure of around 6 bar intensifying the hydraulic fluid used for clamping of gears. The use of hydro-pneumatic enables fast testing along with accuracy and reliability. The figure shows the Hydro Pneumatic intensifier circuit using intensifier and 3/2 spool operated DCV valve which is supplied with air under pressure which further intensifies the oil finallyexpanding the sleeve. Hence, the expansion sleeve expands and engages with the gear making it clamp. The figure below shows the hydro-pneumatic circuit. Page 97

4 Fig 5: Hydro-Pneumatic Intensifier Circuit The entire expanding sleeve, locator, spindle assembly is supported together using the housing, resting ring, adaptor ring, block, cover, bearing holder which are held together using the bearings, pin rod, shoulder screws. The figure shows a compact design of the above assembly. Fig 6: Clamping Assembly The above entire assembly is held on a weldment which holds tightens the above assembly into it and prevents any movements. Welding fabrication is one of the most common joining procedures of metallic structure [8].Hence, the Weldment is done using welding procedures. The figure shows the weldment. Page 98

5 Fig 7: Weldment The weldment is fitted into the stand using nuts and bolts. Hence, the stand holds the entire assembly including the intensifier. The figure shows the stand. Fig 8: Stand After the complete setup of the fixture machine, the Hydro-Pneumatic intensifier is connected to the air supply. Therefore, the air enters the intensifier intensifying the fluid making it pass through spindle, locator and expanding sleeve. When the pressure in the expanding sleeve reaches the desired pressure, it expands and engages with the gear causing gear to be clamped. This gear can be rotated manually to check the TIR using the dial indicator. Therefore, gears with any defects are recognized and accordingly the desired action is taken. The figure below shows the entire assembly of the fixture. Fig 9: Fixture Design Page 99

6 Conclusion The design is quite simple and only the method of clamping makes it distinct from other gear holding fixtures. The hydraulic and pneumatic combination saves lot of weight to the apparatus and makes it compact for use. Additionally, it works efficiently with available pressure and eliminates any further arrangement of pumps, compressors etc. The Total Indicator Reading (T.I. R) is checked with the help of simple dial gauge which is mounted on the whole assembly.the fixture is designed to check the T.I.R. as deviation in reading will indicate that any one or more geometrical parameters of gear are not in conformation with the required ones. The fixture is essentially designed to recognize these geometrical distortions of the gear caused due to heat treatment. Heat treatment of gears after their manufacturing resulted in scaling. This scaling was inevitable in spite of various measures taken by the organization. No provision was available to check this distortion due to heat treatment and several geometrical errors it caused. Consequently, it resulted in increased rejection of gears by the quality department. As the effects due to heat treatment were inevitable and so a process for testing these gears after heat treatment was a must. Therefore to develop a fixture to check the total indicator reading of the gear using hydro-pneumatic intensifier was designed. References [1]. Mr. Bharat Gupta, Mr. AbhishekChoubey, Mr. Gautam V. Varde. "Contact Stress Analysis of Spur Gears". International Journal of Engineering Research & Technology (IJERT), ISSN: ,Vol.1 Issue4, June [2]. AmandeepMavi, MandeepKaur. "Identify Defects in Gears using Digital Image Processing". International Journal of Engineering Research and Development". ISSN: X, Volume I, Issue 6 (June 2012) PP [3]. Paul Munzerberger, Craig Wheeler, "The Influence of 'Maximum Indicated Slope' and 'Total Indicated Run-Out' on the noise caused by the interaction of conveyor idler rolls and conveyor belts", TUNRA Bulk Solids Associates, The University of Newcastle, Australia, B16-02 page2. [4]. VaggeeramHariharan, PSS. Shrinivasan. "Vibration analysis of parallel misaligned shaft with ball bearing system". Songklanakarin Journal of Science and Technology. 33(1), 61-68, Jan.-Feb [5]. 5.Gustavo A. Sanchez, Carlos Gonzalez O. "A low cost system for hydraulic applications". [6]. Afzeri, Nukhaei Ibrahim. "Hybrid Optimization of Pin type fixture Configuration for Free Form Workpiece". International Journal of Engineering, (IJE) Volume (2): Issue (3). [7]. Swapnil R. Nimbhorkar, Prof. B. D. Deshmukh. "Effect of Case Hardening Treatment on the Structure and Properties of Automobile Gears". International Journal of Modern Engineering Research (IJMER), ISSN: , Vol.3, Issue pp [8]. Dr. Ali SadiqYasir. "Study the Effect of Welding Joint Location on the Fatigue Strength and Fatigue Life for Steel Weldment". Asian Transactions on Engineering (ATE ISSN: ) Volume 02 Issue 04. Page 100