Study on the effects of tooth profile design parameters of rotor to performance of vacuum pump

2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040141
Author(s):  
Van-The Tran ◽  
Bui Trung Thanh ◽  
Banh Tien Long ◽  
Hoang Quoc Tuan ◽  
Duc Toan Nguyen
Keyword(s):  
Vacuum Pump ◽  
Tooth Profile ◽  
Design Parameters ◽  
Tooth Root ◽  
Performance Indices ◽  
Circular Arc ◽  
Numerical Example ◽  
Design Flexibility ◽  
Profile Design ◽  
Rotor Tooth

The vacuum pump usually used traditional curves such as the circular, cycloidal curves and their combinations to construct tooth profile. However, to increase efficiency and design flexibility for the vacuum pump, a novel rotor tooth profile for Roots rotor of vacuum pumps is proposed. Which is named “CEIEC” tooth profile and orderly composed of five significant segments, a circular arc for tooth tip, an epicycloid curve with variable extension, an involute, an enveloped epicycloid curve and a conjugated circular arc for tooth root. A numerical example is presented to evaluate the performance indices for proposed vacuum pump, including the hermeticity coefficients of the rotor mesh gap and tip gap.

Study of Tooth Profile Design with Asymmetric Double Circular Arc Gears for Pumps

2010 ◽  
Vol 43 ◽  
pp. 409-413 ◽  
Author(s):  
Yuan Wei Liu ◽  
Jia Fan
Keyword(s):  
Theoretical Foundation ◽  
Tooth Profile ◽  
Design Parameters ◽  
Circular Arc ◽  
The Future ◽  
Gear Pumps ◽  
Profile Design

While transmission theory of asymmetric double circular arc gears is created,the design parameters of asymmetric double circular arc gears are also studied theoretically in this paper. A set of equations for determining asymmetric double circular arc tooth profile are deduced. The theoretical foundation will be laid for designing the gear pumps and reduction boxes in the future productively.

Design constraints of five-arc Roots vacuum pumps

2002 ◽  
Vol 216 (2) ◽  
pp. 225-234 ◽  
Author(s):  
P-Y Wang ◽  
Z-H Fong ◽  
H S Fang
Keyword(s):  
Design Procedure ◽  
Vacuum Pump ◽  
Tooth Profile ◽  
Design Constraints ◽  
Circular Arc ◽  
Ultimate Pressure ◽  
Rotor Profile ◽  
Circular Arcs ◽  
Centre Of Rotation ◽  
Inlet Opening

The design constraints for the tooth profile of the five-arc Roots vacuum pump are derived and discussed in this paper. The addendum portion of the five-arc tooth profile comprises five smoothly connected circular arcs, while the dedendum portion consists of conjugate curves of the addendum portion of the mating rotor. The top land of the proposed rotor profile is a circular arc with its centre coinciding with the centre of rotation. Therefore, the gap between the top land of the rotor and the wall of the chamber turns into a long and narrow path, which provides better gas sealing and wider inlet opening. The design constraints of the rotor profile are quite complex owing to the limitations of zero carryover and the condition of non-undercutting. A design procedure is proposed for determining the feasible design region by considering the geometry constraints, zero carryover and non-undercutting. By using the proposed procedure, wider inlet opening and better gas sealing are expected, while the characteristic of zero carryover is maintained. The results of experiment show that the ultimate pressure of the prototype of the five-arc Roots vacuum pump is 2,5 × 10-3 torr, and the maximum pumping speed is 1600L/min. The performance of the prototype is excellent compared with commercially available mechanical dry vacuum pumps.

Further Evaluation of Spur Gear Tooth Profile Designs Used in Heavily Loaded Transmissions

2011 ◽  
Author(s):  
Nihat Yıldırım ◽  
Hakan I˙s¸c¸i ◽  
Abdullah Akpolat
Keyword(s):  
Gear Tooth ◽  
Transmission Error ◽  
Spur Gear ◽  
Tooth Profile ◽  
Design Parameters ◽  
Preference Order ◽  
Spur Gears ◽  
Tooth Root ◽  
Contact Ratio ◽  
Practical Applications

Aerospace applications require special procedures for component design and manufacturing. Spur gears of different designs, because of their simpler geometries, are used in vital units-transmissions of helicopters and alike aerospace vehicles. In this study, performances of various profile designs of previously researched low and high contact ratio spur gears with some realistic design parameters are studied. Effects of the realistic parameters of variable tooth pair stiffness, relief shape, and adjacent pitch error on Transmission Error (TE), tooth loads and root stresses are presented; composition of these parameters determines the efficiency of the gearbox assembly. Detail of minimization of tooth root stress through optimized/proper design of relief is described. More comprehensive comparison of the gear tooth profile design cases is done to be able to guide aerospace transmission designers for practical applications with realistic parameters for each of the design cases. A preference order is done among the design cases, depending on effect of some design parameters on the results such as tooth loads, tooth root stresses, TE curves and peak-to-peak TE values.

scholarly journals Dimensionless design approach to translating flat faced follower mechanism with two-circular-arc cam

2019 ◽  
Vol 10 (2) ◽  
pp. 497-503
Author(s):  
Emre Arabaci
Keyword(s):  
Rotation Angle ◽  
Maximum Velocity ◽  
Design Approach ◽  
Design Parameters ◽  
Circular Arc ◽  
Dimensionless Parameters ◽  
Absolute Acceleration ◽  
Cam Profile ◽  
Profile Design ◽  
Critical Characteristics

Abstract. In this study, a dimensionless design approach was presented for translating flat-faced follower mechanism with two-circular-arc cam. Instead of second arc radius (r2), maximum follower lift (smax) and angle of the cam rotation angle (2θmax) variables from the cam profile design parameters were made dimensionless using r2∕r (=λ), smax∕r (=ψ) and θmax∕π (=μ) respectively. Equations for cam profile and follower movement were derived and graphics were obtained depending on the dimensionless parameters. λ and ψ should be in the range [0.0, 1.0], but μ should be in the range [0.0, 0.5]. λ and ψ were changed in the range [0.10, 0.90] and μ in the [0.25, 0.45] range and λ, ψ and μ values were determined for the cam profile. Maximum velocity (vmax), maximum absolute acceleration (amax) and average follower lift (save) changes, which are one of the critical characteristics of follower, were examined for possible cam profiles according to the change of λ, ψ and μ. As a result, vmax and save decreased when μ was increased, vmax and save increased and amax decreased when ψ was increased, amax and save increased when λ was increased.

Tooth Root Stress and Tooth Contact Stress of the Modified Cycloid Helical Gear

2003 ◽  
Author(s):  
Florin Gabriel Tutulan ◽  
Kazuteru Nagamura ◽  
Kiyotaka Ikejo
Keyword(s):  
Contact Stress ◽  
Helical Gear ◽  
Contact Stresses ◽  
Measured Data ◽  
Tooth Profile ◽  
Design Parameters ◽  
Present Calculation ◽  
Tooth Root ◽  
Tooth Contact ◽  
Root Stress

This paper describes the relationship between tooth root and tooth contact stresses and the tooth profile of the modified cycloid helical gear, which was developed as a non-involute tooth profile gear based on cycloid tooth profile and which has a greater surface durability than the involute helical gear. The modified cycloid helical gear has some design parameters such as pressure angle and rolling circle, which define the modified cycloid tooth curve. The tooth bending and tooth contact strengths of the modified cycloid helical gear are directly affected by its tooth profile. In this study, we developed a method to calculate the load distribution, the tooth root stress and the tooth contact stress of the modified cycloid helical gear. Then we compared the tooth root stress calculated by this method with the experimentally measured data and the validity of the present calculation method was certified by the good agreement of the calculated values with the measured data. Furthermore, we discussed the effects of the design parameters on the tooth bending and tooth contact strengths of the modified cycloid helical gear considering the results of the tooth root and the tooth contact stresses calculated in the case of various values of the design parameters.

Rotor Profile Design for the Twin-Screw Compressor Based on the Normal-Rack Generation Method

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yu-Ren Wu ◽  
Zhang-Hua Fong
Keyword(s):  
Helix Angle ◽  
Tooth Profile ◽  
Normal System ◽  
Rotor Profile ◽  
Twin Screw ◽  
Screw Rotor ◽  
Profile Design ◽  
Rotor Tooth ◽  
Rotor Profiles ◽  
Screw Rotors

This paper proposes a method for designing the rotor profiles of twin-screw compressors using a rack defined in the normal plane. All tooth profile segments are explicitly defined as tangent continuous in the normal section to generate a pair of conjugated rotors. Numerical comparisons between the two types of screw rotor tooth profile design, one based on a normal system, the other on an axial system, show the advantages of using the normal-rack generation method (NRGM). Most particularly, this method allows the same hob used for screw rotors to be used to manufacture mating rotors even as the helix angle varies, because in a normal system the circular pitch remains the same. The numerical results also indicate that the rotor tooth thickness generated by the NRGM rack cutter can prevent serious deflection for a variety of helix angles and tooth combinations.

The Tooth Profile Design and Examination of Circular-Arc Gear Pump

2014 ◽  
Vol 672-674 ◽  
pp. 1604-1607
Author(s):  
Yang Zhou ◽  
Shuang Hui Hao ◽  
Ming Hui Hao
Keyword(s):  
Tooth Profile ◽  
Gear Pump ◽  
Helical Surface ◽  
Circular Arc ◽  
Engagement Theory ◽  
Flow Fluctuations ◽  
Profile Design ◽  
The Mathematical Model ◽  
Gear Engagement ◽  
Examination Process

This paper presents the circular-arc tooth profile that has no trapped-oil feature and flow fluctuations. The mathematical model of tooth profile and helical surface is obtained by gear engagement theory. The examination of helical surface is by coordinate measuring machining (CMM). The sections that perpendicular to the axis direction of gear are selected to obtain the trajectory of measuring ball by the starting points and end points of measuring ball. The examination process of CMM is simulated by Matlab in this paper.

Study on the High-Sealing of Roots Rotor With Variable Trochoid Ratio

2006 ◽  
Vol 129 (12) ◽  
pp. 1278-1284 ◽  
Author(s):  
Chiu-Fan Hsieh ◽  
Yii-Wen Hwang
Keyword(s):  
Design Procedure ◽  
Vacuum Pump ◽  
Tooth Profile ◽  
Vacuum System ◽  
Design Parameters ◽  
Spline Functions ◽  
Area Efficiency ◽  
High Area ◽  
Order Polynomial ◽  
Fifth Order

Vacuum pump plays an important role in the vacuum system. In this paper, a new method is proposed to design the Roots rotor that was the trochoidal curve with variable trochoid ratio. The fifth-order polynomial and cubic spline functions are used to generate smoothly trochoid ratio functions and thus a regular addendum curve for Roots rotor will be generated. Based on the addendum curve, the tooth profile for the complete Roots rotor is derived by the gearing theory. In order to improve the sealing between the rotor tip and the chamber, a design procedure is also developed for roots rotor with high sealing and high area efficiency. In addition, the undercutting equation is used to study the constraints of design parameters and the center of curvature is used to check the occurrence of the carryover on the tooth profile. Finally, some design examples are presented to show the feasibility of the proposed method.

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