課程名稱︰機械設計
課程性質︰系定必修
課程教師︰尤春風
開課學院：工學院
開課系所︰機械系
考試日期（年月日）︰99.01.14
考試時限（分鐘）：3hr (14:20~17:20) (close+open)
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
I. Close book 部分
1.(10%,每一子題請用文字說明之，每一子題字數請勿少於40字)
Gear may be failure due to the bending stresses if the bending stresses are
too large.
(a) Please describe the failure phenomena due to the bending stresses.
(b) Please give some methods to avoid this problem?
2.(10%,每一子題請用文字說明之，每一子題請勿少於40字)
Gear may be failure due to the contact stresses if the contact stresses are
too large.
(a) Please describe the failure phenomena due th the contact stresses.
(b) Please give some methods to avoid this problem?
3.(8%,請用文字說明之，字數請勿少於50字)
There are two basic modes of potential faailure on the key. Please give
the detail descriptions of the failure modes for the keys (using a drawing
for your descriptions are strongly recommended).
4.(8%)
Bearing arrangement is shown in Fig. 1. Please indicate the improper
arrangement in that drawing and modify the bearing arrangement as the correct
arrangement.
附圖如下: (用手機照的,有點模糊請見諒<(_ _)> )
http://www.flickr.com/photos/jw771216/4285161110/
5.(12%,每一子題請用文字說明之，每一子題字數請勿少於30字)
(a) Why the hole-basis system is mostly used on the industry?
(b) Please give the detail descriptions of tolerance and fit.
(c) What kind fit can be used for the inner race of the bearing with the
shaft?
(d) What kind fit can be used for the outer race of the bearing with the
housing?
6.(12%,每一子題請用文字說明之，每一子題字數請勿少於50字)
Please give the detail descriptions of the following items:
(a) Pitting
(b) Scoring
(c) Static load rating
(d) Dynamic load rating
II. Open book 部分
7.(40%)
A train of spur gear is shown in Fig. 2. Gear 1 is the driving gear and
transmits 5 KW power at 1200 rpm. The number of teeth on gears 1, 2, 3, and
4 are 18, 55, 18 and 55 respectively. The gears have a 20 degree full depth
involute profile.
Please find the following design information:
(a) The modulus (M) of the gear 1 and gear 3.
(b) Specify the surface hardness (HRC) of gear 1 and gear 3.
(c) The necessary diameter of the intermediate shaft (中間軸, shaft is used
to support gear 2 and gear 3).
(d) The candidate bearing (bearing type and size) at support C.
(If it is possible, please make some decisions of suitable dimension for your
calculation).
┌──┐
┼ ─ ┼
│ │
│ ４ │
│ │
output │ │
shaft │ │
─┬───┤ ├───┐
┼ ╳ ─├ ─ ┤─ ╳ ┼
─┴───┤ ├───┘
a │ │ b ┌──┐
│ │ ┼ ─ ┼
│ │ │ │
│ │ │ ２ │
├──┤ │ │
┼ ─ ┼ │ │
├──┤ │ │
│ ３ │ │ │
┌──┤ ├────┤ ├─┐
┼╳─├ ─ ┤─ ─ ─├ ─ ┤╳┼
└──┤ ├────┤ ├─┘
c │ │ │ │ d
│ │ │ │
┼ ─ ┼ │ │
└──┘ │ │
│ │
├──┤
┼ ─ ┼
├──┤
│ １ │
┌──┤ ├────┬─
┼╳─├ ─ ┤─ ─ ╳┼ input
└──┤ ├────┴─ shaft
e │ │ f
│ │
┼ ─ ┼
└──┘
Fig. 2
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