上游充通大学 SHANGHAI JIAO TONG UNIVERSITY LECTURE 7 CAM DESIGN 凸轮机构设计 漏 员员员是 6 SHANG 1日gG ERSITY
LECTURE 7 CAM DESIGN CAM DESIGN 凸轮机构设计
上游充通大学 SHANGHAI JIAO TONG UNIVERSITY .Cam >Convenient device for transforming one motion into another >Has a curved or grooved surface that mates with a follower =Imparts motion to follower Follower oscillation,translation,or both
•Cam ¾Convenient device for transforming one motion into Convenient device for transforming one motion into another ¾Has a curved or grooved surface that mates with a follower =Imparts motion to follower Follower oscillation translation or both Follower oscillation, translation, or both
上游充通大学 Cams compare with linkage SHANGHAI JLAO TONG UNIVERSITY .Linkage advantages >Reliability >Ease of construction >Lower cost .Cam-follower systems more compact than linkages >For same output motion >Can generate a true dwell >Intermittent motion ME357 Design Manufacturing ll
Cams compare with linkage •Linkage advantages Linkage advantages ¾Reliability ¾Ease of construction ¾Lower cost Lower cost •Cam -follower systems more compact than follower systems more compact than linkages ¾For same output motion ¾Can generate a true dwell Can generate a true dwell ¾Intermittent motion ME357 Design & Manufacturing II
上游充通大学 Cam Design Procedure SHANGHAI JIAO TONG UNIVERSITY Type Synthesis ● Selection of cam and follower type based on basic motion requirements 。 Geometric,environmental,and economic considerations Follower Motion Based on specified rise,return,dwell Dimensional Synthesis of Cam Profile ."Wrapping around"follower profile onto cam Analysis Pressure Angle,Radius of Curvature,Dimensional Constraints... ME357 Design Manufacturing ll
Cam Design Procedure Typ y e S ynthesis • Selection of cam and follower type based on basic motion requirements • Geometric, environmental, and economic considerations Follower Motion Follower Motion • Based on specified rise, return, dwell Di i l S th i f C P fil Dimensional Synthesis o f Cam Profil e • “Wrapping around” follower profile onto cam Ali na ys s • Pressure Angle, Radius of Curvature, Dimensional Constraints... ME357 Design & Manufacturing II
上浒文通大学 Cam Terminology SHANGHAI JIAO TONG UNIVERSITY Type of follower motion (rotation,translation) Type of joint closure (force,form) Type of follower (roller,mushroom,flat) Direction of follower motion (radial,axial) Type of motion constraints(critical extreme position(CEP)and critical path motion(CPM)) Type of motion program (rise-fall (RF),rise-fall- dwell (RFD),rise-dwell-fall-dwell(RDFD) ME357 Design Manufacturing Il
Cam Terminology Type of follower motion (rotation, translation) Type of joint closure (force, form) T f f ll ( ll h fl t) Type o f follower (roller, mus hroom, fl at) Direction of follower motion (radial, axial) Direction of follower motion (radial, axial) Type of motion constraints (critical extreme position(CEP) and critical path motion (CPM)) Type of motion program (rise Type of motion program (rise -fall (RF) rise fall (RF), rise -fall - dwell (RFD), rise-dwell-fall-dwell (RDFD) ME357 Design & Manufacturing II
上浒文通大学 Type of Follower Motion SHANGHAI JIAO TONG UNIVERSITY 国 Translating a and Follower Half joint oscillating followers Depends on motion Cam Spring 2 required 4 Half joint Cam 公 02 ⊕ Vfoilower Spring Follower
Type of Follower Motion Translating and Translating and oscillating followers Depends on motion required ME357 Design & Manufacturing II
上游充通大学 Type of Joint Closure SHANGHAI JIAO TONG UNIVERSITY Force and Form Follower Half joint Closed Cams Cam Spring Force closed cams require an external force 2 to keep the cam in contact Half joint with the follower Cam A spring usually supplies this force 2 Vfollower Spring Follower
Type of Joint Closure F dF orce an d Form Closed Cams Closed Cams Force closed cams Force closed cams require an external force to kh i eep t he cam in contact with the followe r A spring usually suppli thi f lies this force ME357 Design & Manufacturing II
上游充通大学 Type of Joint Closure SHANGHAI JIAO TONG UNIVERSITY Form closed cams are closed by joint geometry Slot milled out of the cam Half joint Follower Half joint Conjugate 2 Follower 2 cam com 2 @cam Conjugate 1 Vfollower Follower Track or groove Cam Cam Track or groove ME357 Design Manufacturing Il
Type of Joint Closure Form closed cams are closed by joint geometry Form closed cams are closed by joint geometry Slot milled out of the cam ME357 Design & Manufacturing II
上海文通大粤 Type of Follower SHANGHAI JIAO TONG UNIVERSITY Roller Mushroom Flat-Faced Follower Follower Follower Vfollower Vfollower follower Follower Follower Follower Spring Spring Spring Cam Cam Cam ⊙cam ocam ocam
Type of Follower Roller Mushroom Flat-Faced Follower Follower Follower Roller Follower Roller Follower Mushroom Follower Flat-Faced Follower ME357 Design & Manufacturing II 9
上海文通大 Direction of Follower Motion SHANGHAI JIAO TONG UNIVERSITY Radial.offset or Axial Radial Cam offset Cam Axial Cam Vfollower ollower Cam Half joint pring B ca C Cam Follower cam N Vfollower D ME357 Design Manufacturing ll
Direction of Follower Motion Radial, offset or Axial Radial Cam offset Cam Axial Cam Axial Cam ME357 Design & Manufacturing II
