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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Autodesk Inventor Engineer s Handbook
انجمن اینونتور ایران
www.irinventor.com
irinventor@chmail.irEmail:
irinventor@hotmail.com
Tel: 09352191813 &
021-46088862
قابل توجه خوانندگان عزیر: کلیه مطالب [
Autodeskاین هندبوک از سایت شرکت
]کپی برداری شده است.
Autodesk Inventor هندبوک مهندسی نرم افزار
Transmission Mechanism
Power Screw
Calculator
Handbook
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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Basic calculation of power screws
Calculates power screws loaded by torsion and pressure, and checks for buckling and pressure in
the thread using metric or English units, depending on the specified standard. With the ANSI
standard, English units are used with corresponding screw dimensions.
Input Parameters
F maximal axial force [N, lb]
T maximal.moment [Nm, lb ft]
f 1
thread friction factor between the nut and screw [-]
NoteThe influence of the angle of thread must be included in the thread friction factor value.
d screw thread diameter [mm, in]
p pitch [mm, in]
d s mean screw diameter [mm, in]
d min minimum screw diameter [mm, in]
H nut height [mm, in]
n factor for end conditions according to the diagrammatic picture of mounting types [-]
L maximum loaded length of a screw [mm, in]
S y yield strength [MPa, psi]
k s safety factor (The value is selected according to the required safety level.) [-]
p a allowable thread pressure [MPa, psi]
E screw elasticity module [MPa, psi]
Calculated Parameters
Reduced length
L red = n L
Min. section area
S min = π d min 2 / 4
Helix Angle (Lead angle)
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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Efficiency
For “Rotation to Shift”
For “Shift to Rotation”
If α < arc tan f 1 , η = 0
Maximum moment - if it is the output moment
T = F p / (2 πη)
Maximum axial force - if it is the output force
F = 2 T πη / p
Slenderness ratio
λ = 4 L red / d s
Pressure stress
σ t = F / S min
Torsion stress
Reduced stress
Rankin Critical Stress
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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Euler Critical Stress
σ E = π 2 E / λ 2
Johnson Critical Stress
Calculated thread pressure
Calculated factor of safety
k v = min (S y / σred, min (σ R , σ F , σ J ) / σ t )
Strength check
k v ≥ k s
p c ≤ p A
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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Thread friction factor f1
Thread f 1
Acme thread 0.1 to 0.2
Ball power screws 0.01
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AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
Allowable thread pressure pa
For power screws
Material pa [MPa] pa [psi]
Steel - Cast iron 5 - 7 700 - 1000
Steel - Bronze 5 - 15 700 - 2200
Steel - Steel 7.5 - 10 1100 - 1450
Mounting Type:
The values are theoretical. You must include backlash and yielding in mounting.
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Web: www.irinventor.ir Email: irinventor@chmail.ir & irinventor@hotmail.com Tel: 09352191813 & 021-46088862
7
AUTODESK INVENTORانجمن اینونتور ایران/ هندبوک مهندسی نرم افزار
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