DESIGNAND ANALYSIS OF HYDRAULIC CENTERING MACHINE

Transcription

1 DESIGNAND ANALYSIS OF HYDRAULIC CENTERING MACHINE 1 Nainesh Nahar, BE-Mechanical, VIIT Pune 2 Shubham Jain, BE-Mechanical, VIIT Pune 3 Prof. M.G. Gadge, Department of Mechanical Engineering, VIIT Pune ABSTRACT-The objective of this paper is to present Design of Hydraulic Centering Machine. This machine is used for balancing of bending bar in piston of steering gear. The prime moto behind this study is to increase the productivity of the machine in operating hours per shift. By the study, it is found that the production rate can be increased by 33% per shift. That leads to increase in productivity by 45-50% per shift. Motor power is reduced from 10HP to 2HP (1HP two motors). Current machine is bulky and has higher power consumption. This design allows us to have compact sized machine along with extended benefit of lower power consumption.current machine has a single fixture operating ; while this new design helps in accommodating two fixtures on a single platform for balancing. The overlook positive benefits of the design will be, a fully functional digital display over conventional analog gauges. Additional aspects assumed in design is use of thermostat to maintain the oil temperature at 45-55ºC which helps in reducing the friction, oxidation & impurity of oil as well increase the accuracy. This helps in smooth functioning between the fixture and piston while balancing. Keywords- Hydraulic Centering, piston, torsional bar, Steering Gear, Productivity INTRODUCTION Hydraulic centering is used in power steering gears. It is a process carried out for balancing of torsional/bending bar in the neutral position of the piston of steering gear. This helps in minimizing the effort while steering. This further helps in return of wheels to the mean position. The power consumption can be reduced. The productivity can be increased by 45-50% per shift. The display unit used are fully digital over analog which helps in increasing the accuracy. Two fixtures can be accommodated on single platform. 19

2 CLASSIFICATION OF POWER STEERING SYSTEM Power steering gears Light Weight Vehicle Heavy Weight Vehicle Multi Utility Vehicle (LH) (RH) (Regular) (RH) (Facemounted) 1. M033 (LH) 2. M033(RH) Figure 1. Classification of power steering gear.[1] BALL AND NUT TYPE POWER STEERING GEAR. Figure 2. Ball and Nut type power steering gear.[1] 20

3 TECHNICAL SPECIFICATION. PARAMETERS Suitable for vehicle with FAW SPECIFICATIONS kg Steering ratios 23,6:1 20.1:1 Hand of vehicles Steering gear hand Controlled flow rate Maximum pressure RHD/LHD RH/LH 16 dm3/min 150 bar Dimension Maximum drop arm travel No of steering wheels turns Pressure relief valve Hydraulic steering limiter Blending arrangement Assembly weight Mounting holes 49 degree Each 5.9 at 90 degree Inbuilt Manual Automatic 40.2 kg M18*1.5-4 NOS Input shaft serrations 1* 79 ZGN 738 Max torque 5356 Nm Table No.1. Technical Specification [1] OBJECTIVE OF DESIGNING To increase the overall efficiency of the machine. To reduce the power consumption by using required capacity pumps. Improve production rate. To combine the working of two machines on a single platform. 21

4 EXPERIMENTAL SETUP:- 1. PINION The following piston is mounted on the fixtures of the machine to carry out centering process. The piston consists of end cover, worm, set screw, valve spool & piston teeth. Figure 3.Piston [2] 22

5 2. MACHINE SETUP Figure 4. Machine setup[4] 2.1 Pump Pump helps in regulating the oil flow from reservoir to the fixture. Pump of 2HP (1HP each)is used to obtain pressure of 40 bar 2.2 Fixtures The operation of fixture is to position the piston in a neutral position for hydraulic centering. 2.3 Oil reservoir The oil used is Gulf ATF Type A. Its benefits are as follows:- Good oxidation & thermal stability Provides good anti-wear protection to critical parts. Extremely high viscosity index ensures adequate lubrication in both high operating and low starting temperature. Provides good protection against rust and corrosion. Good foam control leads to smooth gear shifting Specification Approvals and Typical properties 23

6 Test Parameters ASTM Method Typical values Viscosity at 100ºC, cst D Viscosity index D Flash point ºC D Pour point ºC D Brookfield - D ºC Density at 15ºC,kg/l D WORKING 3.1 CLAMPING OF PISTON Table No.2. Specification of Gulf ATF Type A Oil. [2&3] Attach seals to piston & insert into fixtures with assembly pliers, noting correct positing of splines. Clamp the piston to locate it, then release it again.attach cover with screw. Tighten the thread ring for the torsion bar to 8-10 Nm. 3.2 INITIAL HYDRAULIC CENTERING After moving out in both direction & by turning the torsion bar,the two pointers of the differential pressure gauge must be set to approximately the same value. Deviation of 1-2 scale marking are permissible. Check pressure on both side 3.3 CHECKING OIL LEAKOFF Deflect fully to both side, with the pressure held for approx 10 sec. Oil leak off must not exceed 1.2 l/min. RESULT The new designed machine helps in increasing the production rate upto 45-50% per shift. The quality and accuracy of the product is increased by using Gulf ATF oil while centering. It is now possible to operate two fixtures on a single platform which reduces the floor space and increases the productivity. Cover framing helps in preventing foreign particles to enter the machine. The power consumption is reduced by using lower HP pumps. Thermostat helps in maintaining the oil temperature at standard operating condition. CONCLUSION Two jobs can be operated simultaneously on a single machine. The production rate can be increased by 33% per shift. That leads to increase in productivity by 45-50% per shift. The power consumption is reduced. Thermostat is used to maintain the oil temperature at 45-55ºC which helps in reducing the friction, oxidation & impurity of oil as well increase the accuracy. 24

7 This helps in smooth functioning between the fixture and piston while balancing. A digitalized functioning system is now used. ACKNOWLEDGEMENT The authors are grateful to Mr. A. Ravi (ZF Steering Gears Ltd) & Prof. M.G. Gadge for his support and guidance. REFERENCE 1. ZF Steering Gears Ltd Data book (ZF Steering gears ltd.) 4. Solidworks software for designing. (2015 version) 25