of Technology, Mechanical Engineering Department Nguyen Tan Tien Nguyen Tan Tien. Theory of Machine[r]
Trang 1HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
4 MA SÁT
Trang 2HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
A B
r
Nr
Fr
t
Fr
r
Rr
t
ϕ
N
F
ft= max
t
N
F
=
tanϕ
Trang 3HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
A B
Pr
Nr
Fr d
Fr
Sr
Rr
d
ϕ
N
F
d =
d d
N
F =
=
ϕ
tan
max
Fr d
Fr
Fr
N f F
N f F
d d
t
=
= max
Trang 4HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
-Tácd nglênAmộtlực Pr(Prx,Pry)
ϕ α
ϕ α
α α
≥
=
≥
≥ tan tan
cos sin
f
P f P
A B
α
Pr
x
Pr
y
Pr
ms
Fr
Nr
) tan(α+ϕ
≥ Q P
o α+ ϕ> π/ 2 tan (α+ϕ) < 0 →Pn mtheochiề ngượclại
≥ +
Nr
Rr ϕ α
α
Fr
ϕ
α +
Pr B
A
Trang 5HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
o α-ϕ < 0 tan (α-ϕ) < 0 →Qn mtheochiề ngượclại
) tan(α−ϕ
Q
Nr R r
ϕ α
α
Fr
ϕ
α −
Qv Sr
Pr A
B
Q
P
Trang 6HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
N ′r N ′r
Nr
Nr
Fr Pr
β
β
β
cos 2
cos 2 Q N
Q N
N
=
⇒
=
=
′
Q f Q f N f P
F P
′
=
=
≥
⇒
≥
β
cos 2
2
4 4 4 4 4 4 4 4 4
4 4 4 4 4 4 4 4
1
Trang 7Mr
HCM City Univ of Technology, Mechanical Engineering Department Nguyen Tan Tien
Qr
Qr
Pr
Pr tb r
tb
d
t π
λ arctan=
Qr
Pr
λ
tb d
π
) tan(α±ϕ
=
≥
⇒M Mms rtbQ
Mr
Qr
Mr
Qr
Pr
λ
tb d
π
β
Qr
Pr
Pr tb r
β
ϕ
cos arctan f
=
′
tb
d
t π
λ arctan=
) tan(
) tan(
ϕ α
ϕ α
′
±
=
′
±
= Q r M
Q P
tb ms
