Dimensional Synthesis (综合)
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E3 B3
Similarly, bisect(平分) C1C2 and C2C3. The intersection(交点) of the two bisectors(平分线) is F1 F2 the fixed pivot D.
F3 E2 B2 A C3 E1 B1 D C2 C1
E3 B3
If the three points C1, C2, C3 locate on a straight line, the the rocker become a sliding block.
铸造车间大型翻砂机的翻箱机构
热处理炉门机构
(1) The fixed pivots(铰链) have not been determined F2 A revolute fourbar mechanism ABCD is to be F3
designed to guide E2 a line segment(段) EF on the coupler
F1
passing through three specified positions E1F1, E2F2 and E3F3.
E1
E3
Points B1 and C1 can be chosen arbitrarily(任 意地) on the first position of the coupler.
E1 B1 E3
Constructing quadrilaterals B3C3F3E3 B1C1F1E1, we get points B3 and C3.
F2 F3 E2 B2 C3 E1 B1 E3 B3 C2
F1
C1
Since the locus(轨迹) of the point B relative to the frame is a circle the centre of which is the F1 F2 fixed pivot A, a circle is constructed F3 C1 passing through E2 C2 the three points C3 B1, B2 and B3. B2
ABCD is to be designed to guide EF on the coupler BC through three specified positions.
F1 E1 F2 E2
F3 E3
The points E and F are selected as the moving revolute centres B and C, rห้องสมุดไป่ตู้spectively.
E1 B1 E3 B3
Since the locus(轨迹) of the point B relative to the frame is a circle the centre of which is the F1 F2 fixed pivot A, a circle is constructed F3 C1 passing through E2 C2 the three points C3 B1, B2 and B3. B2 E1 The centre of A B1 the circle is the fixed pivot A.
1
B A
2
C
e
The accuracy(精度) of the graphical methods by hands is insufficient(不够的). However, the accuracy of the graphical methods is good enough if AutoCAD is used.
Usually, different problems will use different methods. •Graphical method
•Analytical method
•Experimental method
4.4.1 Body Guidance(刚体导引)
A linkage mechanism is to be design to guide a line segment on the coupler passing through some specified positions. Such a synthesis problem is called body guidance.
A A (a) (a) (b) (b)
B B
A A
B B
Dimensional synthesis(综合) of a mechanism is the determination of the kinematic dimensions necessary to achieve(获得) the required motion.
F2 F3 E2 E1 B1 E3 F1
C1
The shape of the quadrilateral(四边形) BCFE should remain the same in all positions. Constructing F1 F2 quadrilaterals B2C2F2E2 F3 C1 B1C1F1E1, we E2 C2 get points B2, and C2. B2
4.4 Dimensional Synthesis (综合) Dimensions affecting(影响) the motion of the mechanism are called kinematics dimensions(运动学尺寸).
LAB between the centres of the two holes in the coupler is the only kinematics dimension.
C 1(F1) B1 ( E1) C 2( F2 ) B 2(E 2)
C 3( F3) B 3(E 3)
The centre of a circle passing through the three points B1, B2 and B3 is the fixed pivot A.
Similarly, bisect(平分) C1C2 and C2C3. The intersection(交点) of the two bisectors(平分线) is F1 F2 the fixed pivot D.
F3 E2 B2 A C3 E1 B1 D C2 C1
E3 B3
If the three points C1, C2, C3 locate on a straight line, the the rocker become a sliding block.
铸造车间大型翻砂机的翻箱机构
热处理炉门机构
(1) The fixed pivots(铰链) have not been determined F2 A revolute fourbar mechanism ABCD is to be F3
designed to guide E2 a line segment(段) EF on the coupler
F1
passing through three specified positions E1F1, E2F2 and E3F3.
E1
E3
Points B1 and C1 can be chosen arbitrarily(任 意地) on the first position of the coupler.
E1 B1 E3
Constructing quadrilaterals B3C3F3E3 B1C1F1E1, we get points B3 and C3.
F2 F3 E2 B2 C3 E1 B1 E3 B3 C2
F1
C1
Since the locus(轨迹) of the point B relative to the frame is a circle the centre of which is the F1 F2 fixed pivot A, a circle is constructed F3 C1 passing through E2 C2 the three points C3 B1, B2 and B3. B2
ABCD is to be designed to guide EF on the coupler BC through three specified positions.
F1 E1 F2 E2
F3 E3
The points E and F are selected as the moving revolute centres B and C, rห้องสมุดไป่ตู้spectively.
E1 B1 E3 B3
Since the locus(轨迹) of the point B relative to the frame is a circle the centre of which is the F1 F2 fixed pivot A, a circle is constructed F3 C1 passing through E2 C2 the three points C3 B1, B2 and B3. B2 E1 The centre of A B1 the circle is the fixed pivot A.
1
B A
2
C
e
The accuracy(精度) of the graphical methods by hands is insufficient(不够的). However, the accuracy of the graphical methods is good enough if AutoCAD is used.
Usually, different problems will use different methods. •Graphical method
•Analytical method
•Experimental method
4.4.1 Body Guidance(刚体导引)
A linkage mechanism is to be design to guide a line segment on the coupler passing through some specified positions. Such a synthesis problem is called body guidance.
A A (a) (a) (b) (b)
B B
A A
B B
Dimensional synthesis(综合) of a mechanism is the determination of the kinematic dimensions necessary to achieve(获得) the required motion.
F2 F3 E2 E1 B1 E3 F1
C1
The shape of the quadrilateral(四边形) BCFE should remain the same in all positions. Constructing F1 F2 quadrilaterals B2C2F2E2 F3 C1 B1C1F1E1, we E2 C2 get points B2, and C2. B2
4.4 Dimensional Synthesis (综合) Dimensions affecting(影响) the motion of the mechanism are called kinematics dimensions(运动学尺寸).
LAB between the centres of the two holes in the coupler is the only kinematics dimension.
C 1(F1) B1 ( E1) C 2( F2 ) B 2(E 2)
C 3( F3) B 3(E 3)
The centre of a circle passing through the three points B1, B2 and B3 is the fixed pivot A.