Experiment of Machinery 1 & 2 - APS
Mechanics
5.3 Gear Shaper Institutional motion diagram mapping and analysis
Rack Generation with gear blank and cutter rotation
CY
- gear blank : rotation, cutter relieving
- cutter : indexing, rotation
YJ-79
- cutter : cutter relieving, cutting
- gear blank : rotation, indexing
YJ-79
cutting motion
- belt
- Slider-crank
- gear chain
indexing motion
- ratchet
- spring
- belt
- cam
- gear chain
- Slider-crank
Generation Motion
- belt
- turbine
- worm gear
5.5 Generating Motion
Aim:
- how work
- root cutting
DO
with pencil
Cutter : $m=18mm, h^*_a=1,\alpha=20^\circ,c^*=0.25$
Gear : $d_1=306mm,d_2=162mm, z_1=d_1/m=17,z_2=d_2/m=9$
- Pitch circle : $d=mz=18*17/9$
- Base circle : $r_b=r\cos\alpha$
- $r_a=r+h_a=r+h^*_am$
- $r_f=r-h_f=r-(h^*_a+c^*)m$
5.8 Slider-crank
sensor
0-100r/min
- laser pulse : displacement of slide,v,a
- motor : set velocity
DO
set sample time
$K=\dfrac{t_1}{t_2}=\dfrac{\alpha_1}{\alpha_2}$
Mechanical Engineering Material
6.1 Metallographic microscope utilize and sample making
Step1
- turn on light
- sample face down
- Coarse adjustment, and then fine, till light and clean
Step2
- get piece of material,small of axis, 2mm
- coarse grinding, make a plane
- fine grind, 0-06#
- polishing
- check by eye
- 3%-4% density Nitric acid alcohol solution, water, alcohol, dry
- black Grain boundary
6.2 Watch different Microstructure
3%-4% density Nitric acid alcohol solution & Sodium picrate
color revert
6.3
6.4 Hardness measurement
| Brinell Scale HB S/W | Rockwell ScaleHR B/C/A, hard to soft |
|---|---|
| Soft : low-carbon steel,non-ferrous alloy Hardened steel sphere/ alloy sphere $HB=0.102\dfrac{F}{S}$ |
120 degree diamond spheroconical : C/A steel sphere : B |
 |
 |
Step1
find the head and lasting time according to estimating hardness
turn on, set time by the screw
turn hand wheel till head against the surface and wheel slippe
push load button and screw the screw to turn on the timer
measurement the diameter, get hardness from table
$HBS=\dfrac{F}{\pi Dh}=\dfrac{2F}{\pi D(D-\sqrt{D^2-d^2})}$
Step2
find head by the estimating hardness
turn hand wheel till head and sample touch,dial point to number 3, initial pressure 10kgf
get the outside dial turn to 0
turn load wheel to pointer to the wanting number 3-5 s, then remove the load
read the number, outside for HRA HRC, inside for HRB
6.5
Interchangeability
7.1.1
7.2.1
7.3.1 Surface Roughness Measurement
K the gain
$R_z=i\dfrac{|(h_1+h_2+\cdots+h_5)-(h_6+h_7+\cdots+h_{10})|}{5} {\rm \mu m}$
$\overline{R_z}=\dfrac{R_{z1}+R_{z2}+\cdots+R_{zn}}{n}{\rm \mu m}$
Step
- estimate the tested sample with the model, decide the sample length and judge length
- turn on the microscope
- coarse justify the focal length
- loose 3
- screw down 6 to down place
- screw up till green band in the eyepiece
- fine justify 14 near the eyepiece
- loose screw at eyepiece turn to one line parallel to the light band
7.4 Screw Thread Measurement
Aim
- Major diameter
- Pitch
- flank angle
Step
just the focus, and so on of the instrument [expensive, only 2 of them, skip, justify by the teacher]
flank angle
screw the front and side to move the cross at mid of the tooth
screw the wheel beside the eyepiece
the A-A dotted line from vertical 0 degree to parallel close to the line of the tooth
measure 4 place
$\dfrac{\alpha}{2}(left)=\dfrac{\dfrac{\alpha}{2}(\rm I)+\dfrac{\alpha}{2}(IV)}{2}\\dfrac{\alpha}{2}(right)=\dfrac{\dfrac{\alpha}{2}(\rm II)+\dfrac{\alpha}{2}(III)}{2}$
ERROR : $\Delta \dfrac{\alpha}{2}( \rm left)=\dfrac{\alpha}{2}( \rm left)-\dfrac{\alpha}{2}\\Delta \dfrac{\alpha}{2}( \rm right)=\dfrac{\alpha}{2}( \rm right)-\dfrac{\alpha}{2}$
Major diameter
- let A-A half in the screw and A-A touch the line of tooth
- read the front wheel number
- move front wheel to II, get $d_2(left)$
- III, IV, get$d_2(right)$
$d_2=\dfrac{d_2({\rm left})+d_2({\rm right})}{2}$
$\Delta d_2=d_{2m}-d_2$
Pitch
- A-A touch the line read the number of side wheel
- move to n pitch II, read side wheel
- same III, IV
$P_{nm}=\dfrac{P_{n{\rm left}}+P_{n{\rm right}}}{2}$
$\Delta P_n=P_{nm}-P_n$
7.5.5 Gear base tangent length deviation measurement
Pitch Unevenness
Step
- calculate $W=m[1.476\times(2n-1)+0.014z], n={\rm round}(\dfrac{z}{9}+\dfrac{1}{2})$
- just to 0
- measure around the gear
length variation : $\Delta F_W=W_{max}-W_{min}$
average length error : $\Delta E_W=W_{av}-W=\dfrac{\sum\limits^z_1 W_i}{z}-W$
Satisfaction $\Delta F_W\le F_W\E_{Wi}\le\Delta E_W\le E_{Ws}\E_{Ws}=E_{ss}\cos\alpha-0.72F_r\sin\alpha\E_{Wi}=E_{si}\cos\alpha+0.72F_r\sin\alpha$
- $E_{ss}$ : tooth thickness upper dievation
- $E_{si}$ : tooth thickness lower dievation
- $F_r$ : Radial runout tolerance
Mechanical Design
9.3 Belt Drive
Slip ratio
$\varepsilon=\dfrac{v_1-v_2}{v_1}=\dfrac{d_1n_1-d_2n_2}{d_1n_1}$
Effectiveness
$\eta=\dfrac{P_2}{P_1}=\dfrac{T_2n_2}{T_1n_1}$
Step
- Set initial force $F_0$
- turn off the velocity knob, then turn on power, clean, and set to rotating speed to 1200$\pm$5 r/min
- record the rotating speed and torque of the forced wheel with no load
- then add load, just the rotating speed of the major, record
- do 8 times
- close all, clean all
- draw $\varepsilon -T_2$, $\eta- T_2$ graphs
9.5.1 Closed gear
$P_1=P_9-P_9\times\eta_{sum}$
Effectiveness
$\eta=\sqrt{\dfrac{T_9-T_1}{T_9}}$
Transmission ratio=1
T9
$T=\frac{WL}{2}=T_9$
Step
- turn down knob to 0, turn on power
- clean all
- set rotating speed to 300-800r/min
- Weight on the plate, record
- then next, record till 8 of weight
- clean all, close all
- draw $\eta-T_9$ and $T_1-T_9$
9.7 Knowing gear reducer
1 class
- cylindrical gear
- Bevel gear
2 class
- unfolding
- Coaxial
- Diversion
Step
- pull pin
- screw off bolt and the cap axis end
- screw off the upper lid, and get it off
- get off the bearing and gear on the shaft, watch the shaft
- knowing the way how gear fix on the shaft
- how the gear reducer work and place
- assemble it back