Structure design of interference fit
1 matching parts must be easy to mount
2 interference fit should have a clear positioning structure
3 avoid pressing at the same time into two mating surfaces
4 the interference fit parts should be taken into account.
5 avoid the same fit size into multiple interference fit parts
6 pay attention to the influence of working temperature on the interference fit
7 pay attention to the influence of centrifugal force on interference fit
8 to consider the two parts with interference fit assembly, the other dimensions of change
9 cone shaft shoulder positioning can not be used
10 cone taper should not be too small.
11 the small shaft embedded in the cast iron is easy to loosen.
12 stainless steel sleeve due to temperature effect will make the surplus with loose
13 interference fit shaft and hub, with a certain length of the surface
14 interference fit and key comprehensive use, should first install type slot
15 do not make the hole of the two same diameter to make interference fit
16 avoid interference fit on the set of asymmetric cut
Two, flexible transmission structure design
　
1 belt drive should increase the ferry angle
2 axis in the pulley position should enable the belt sag to increase angle
3 small pulley diameter should not be too small.
4 belt drive speed should not be too low or too high
5 belt wheel center distance can not be too small
6 belt drive center distance to be able to adjust
7 belt to be easy to replace
8 belt too wide when the belt wheel is not installed
9 by self weight tension belt drive, when the weight is not enough to add auxiliary device
10 axis parallel degree and belt wheel center
11 flat belt drive small belt wheel shall be convex
12 with wheel working surface should be smooth
13 half cross flat belt drive can not be reversed
14 high speed wheel surface should be slotted
15 the installation requirements of the synchronous belt drive is higher than that of the ordinary flat belt
16 synchronous belt wheel should consider installing ring
17 increase the radius of the top of the tooth and the top of the gear tooth
18 the outer diameter of the synchronous belt is suitable to adopt the positive deviation
19 chain drive should be tight side in the
20 two wheels under the arrangement, the small chain wheel on top
21 can not use a chain to drive a horizontal line more than a chain wheel
22 pay attention to the influence of the change of the tension of the flexible drive on the bearing load
23 chain with a small amount of oil lubrication as well
24 chain drive should be able to adjust the center distance
25 the direction of the chain and the chain to adapt to the direction of the chain
26 belt and chain transmission should be added cover
27 the diameter of the rope pulley shall not be arbitrarily reduced.
28 wire rope should avoid repeated bending
29 designers have strict regulations scrapped rope
30 wire rope must be lubricated periodically
31 the surface of the drum should have a rope groove
Three, gear transmission structure design
　
1 gear arrangement should be considered to be beneficial to the shaft and bearing capacity
Two direction 2 herringbone gear tooth combination (A) should first enter the engagement
3 the diameter of the gear should be used as the gear shaft.
4 gear root circle diameter can be smaller than the diameter of the shaft
5 the width of the pinion is greater than the width of the big gear
6 gear block to consider the distance from the cutting tool
7 gear and shaft coupling to reduce the assembly processing
8 pay attention to ensure the consistency of the gear stiffness along the tooth width
9 to compensate the deformation of the shaft by the uneven deformation of the gear
10 split big gear should be no separate spokes
11 the hardening layer on the surface of the gear teeth should not be interrupted
12 bevel gear shaft must be fixed in two way
13 the size of the bevel gear shaft should be able to make the axial adjustment
14 the bolt is not affected by the tension in the structure of the combined bevel gear
Four, worm drive structure design
　
1 worm self locking is not reliable
2 cooling fan should be installed on the worm
3 the direction of the cooling method of the outer heat sink of the worm reducer is related to the cooling method.
4 worm is more serious than the worm gear
5 the position of the worm is related to the rotational speed.
6 worm stiffness is not only determined by the force of the work
7 worm drive complex influence precision mechanical precision
8 the effect of worm drive on the flexibility of rotation
Five, reducer and transmission structure design
　
1 drive unit should strive to form a component
2 transmission ratio is not too large or too small
3 transmission of large power should be diverted to drive
4 as far as possible to avoid the use of vertical reducer
5 pay attention to the balance of internal and external pressure
6 box surface should not be used
7 vertical enclosure should be prevented from leaking oil
8 cases should have enough oil and timely replacement.
9 planetary gear reducer should have both load device
10 gear box gear to move the neutral position
11 transmission gear to round tooth
12 the friction wheel and the friction stepless speed changer should avoid the geometric sliding
13 soft material for active friction wheel
14 cone friction wheel drive, the compression spring should be installed in the small cone friction wheel
15 the design should try to increase the force transmission way, and the compression force into the internal force
16 the mechanical characteristics of the continuously variable transmission should be matched with the working machine and the prime mover.
17 CVT pulley cone bus line of work
Six, transmission system structure design
　
1 to avoid the phenomenon of the movement of the hinge four bar mechanism
Note 2 dead bodies
3 avoid the side thrust of the guide rail
4 limit switches should be set in the linkage mechanism of the larger component
5 pay attention to the transmission angle should not be too small
6 the swinging rod of the cylinder cam with oscillating follower should not be too short.
7 to arrange the position of the guide rail of the offset follower plate cam moving follower
Balance of 8 planar linkage mechanisms
9 the design of intermittent motion mechanism should consider the coefficient of motion
10 the reliability of locking device is analyzed by using the transient analysis.
11 select the type of gear transmission, the first consideration with cylindrical gears
12 mechanical requirements of the reversal, the general can be considered to reverse the motor
13 must take into account the starting performance of the prime mover
14 the hoisting mechanism of the crane shall not be driven by friction.
15 for the requirements of the slow movement of the body, the spiral is better than the rack
16 the large transmission ratio of the standard gear box instead of the bulk of the transmission
17 with a reduction motor instead of the original motive and transmission
18 shaft mounted reducer
Seven, coupling clutch structure design
　
1 reasonable choice of the type of coupling
2 coupling balance
3 have sliding friction coupling should pay attention to keep good lubrication condition
4 high speed rotating shaft coupling can not be prominent in the external projections
5 use the coupling with the convex shoulder and the groove on the shaft.
6 axis twoThe flexible coupling with elastic element is not suitable to be used in the synchronous rotation of the end transmission parts.
7 no bearing at both ends of the intermediate shaft, do not use the slider coupling
8 single universal coupling can not achieve synchronization between the two axes of rotation
9 do not use the gear shaft coupling to do the brake wheel
10 pay attention to the lubrication of gear shaft coupling
11 matters needing attention of nylon rope coupling
12 notice of the shear pin type safety clutch
13 separate the rapid occasion not to use oil lubricated friction disc clutch
14 in the case of high temperature work is not suitable for the use of multi disc friction clutch
15 the clutch control ring shall be mounted on a semi clutch attached to the driven shaft.
Eight, shaft structure design
　
1 minimize the stress concentration at the section of the shaft.
2 to reduce the stress concentration in the interference fit.
3 Effects to stress concentration caused by the shaft keyway
4 to reduce the interference fit parts assembly and disassembly difficulties
5 assembly starting point not sharp, with two surface starting point not assembly
6 axis positioning parts to the shoulder or collar
7 blind holes in the interference fit into consideration should be given to discharge the air shaft
8 the parts and the structure of the shaft are arranged reasonably to reduce the force of the shaft.
9 the load split is used to increase the strength and stiffness of the shaft.
10 using the central and other distance drive to prevent the distortion of the two ends of the torsion
11 improve the surface quality of the shaft, improve the fatigue strength of the shaft
12 shaft multikeyway position setting should be reasonable
Thick wall 13 hollow shaft keyway bottom not too thin
The 14 shaft keyway to convenient processing
15 it is difficult to drill a hole on a shaft.
16 cut threads on the rotary shaft to be beneficial to the fastening nut.
17 ensure the correct installation of the stop washer on the shaft.
18 to ensure that the shaft and the installation of parts of the gap between the size of the compression or clearance
19 to avoid the elastic clamping ring to bear the axial force
20 hollow coupling material
21 do not allow the shaft to be in line with its natural frequency.
22 high speed shaft of the flexible coupling to try to close to the bearing
23 to avoid the bearing of the shaft is zero.
24 it is not suitable to be directly connected to the shaft at the shaft end of the large shaft.
25 axis neck surface requires sufficient hardness
Nine, sliding bearing structure design
　
1 to make the lubricating oil can smoothly into the friction surface
2 lubricating oil should be introduced from non bearing area bearing
3 do not make the whole ring oil groove in the middle of the bearing.
The joint 4 split bearing shell should open oil channel
5 to make the oil ring to the oil fully reliable
6 do not plug the hole
7 do not form a non flowing area of lubricating oil
8 to prevent the sharp edge of the oil film cutting edge or corner
9 step wear
10 do not make the bearing thrust face line contact
11 thrust bearing and the journal should not all contact
12 high speed rotary shaft of heavy duty machinery need high pressure top shaft system
Bearing 13 don't bear heavy load or high temperature rise of the bearing and the bearing contact surface hollowed out
14 do not occur or not dismantle bearing bush situation
15 to reduce the intermediate wheel and cantilever shaft bearing the edge of the bearing generated
16 in the bearing seat hole is not concentric or under the load bearing the axis of the deflection under the condition of the choice to choose the automatic adjustment of the heart sliding bearing
17 bearing and bearing seat does not allow relative movement
18 to make the two kinds of metal bearing in the metal attached to solid
19 ensure proper running clearance.
20 to ensure that the work of the shaft when the gap between the need for thermal expansion
21 consider the gap adjustment after wear
The cylindrical bearing 22 in high speed and light load conditions to prevent instability
23 bearings with high speed and light load condition should be used to select good vibration resistance.
24 oil bearing is not suitable for use in high speed or continuous rotation.
25 sliding bearing and sealing ring combination
26 in the bearing cover or the upper half body in the process of ascension do not make bearing off
Ten, rolling bearing shaft structure design
　
1 consider the design of bearing removal
2 bearing inner ring fillet radius and shaft shoulder fillet radius
3 a combination of a diagonal contact bearing
4 angular contact bearing
5 angular contact bearings should not be paired with non - adjusted gap bearings
6 bearing assembly should be conducive to the uniform load sharing
7 to ensure the need for expansion or contraction of the shaft due to temperature change
8 considering the temperature change of the inner and outer ring and the combination of the tapered roller bearing
9 axial positioning with high accuracy of the axis should be used to adjust the axial clearance of the bearing
10 cruise ships, the middle of the wheel should not be used to support a rolling bearing
11 in the two seat hole is not concentric or use axes under load occur deformation under the condition of shaft bearing with self-aligning properties to choose
12 the design of the multi pivot bearing with equal diameter axis should consider the difficulty of the installation of the middle bearing.
13 does not apply to high speed rotary rolling bearings
14 rigid bearing with high stiffness is required.
15 rolling bearings should not be used in combination with plain bearings
16 grease lubricated roller bearings and dust, sealed bearing easy to heat
17 avoid excess grease, do not form the end of the flow of grease
18 angular contact bearing grease installed on the vertical axis, to prevent the occurrence of fat from the bottom out of the bearing
19 grease lubrication to avoid oil, fat mixture
20 oil lubrication should pay attention to the problem
21 bearing box shape and the influence of rigidity
22 bearing seat force direction should point to support the bottom surface
The 23 hole bearing installation on the base should be simplified bore
24 for the bearing outer ring can not be separated in a hole in the installation should be convenient
25 it is not suitable to use the method of axial tightening to prevent the movement of the bearing with the surface.
Eleven, sealing device structure design
　
1 between the static sealing gasket can not be loaded wire
2 the surface of the static connection should have a certain degree of roughness
3 high pressure vessel sealing contact surface width should be small
4 sealing with the edge of the blade should be added to the gasket
5.O - shaped sealing ring for high pressure seal, there should be a protective ring
6 avoid O ring edge convex cut
7 when the central position of the shaft with the sealing contact often changes, it is not suitable to use the contact type seal
8 correct use of skin ring seal
9 not rely on screw to press the seal packing gland
10 packing more, fill the hole deep compaction is not enough
11 to prevent filler hair
One2 different parts of the seal should be supplied separately.
13 oil lubrication sealing device, to maintain a certain height of the oil surface
14 when the sealing ring gap, multi ring gap should be staggered
Twelve, hydraulic system and pipeline structure design
　
1 pipeline arrangement to facilitate disassembly and inspection
The strength of the Y shaped joint of the 2 big diameter pipes is very poor
3 to avoid mixed with air in the oil pipeline
4 should pay attention to the lower part of pipe drainage
5 discharge pipe should avoid interference with each other
6 pipe to be unobstructed, to avoid disturbance when merging
7 avoid the stress caused by the expansion of the pipeline
8 piping system requires frequent operation, observation of the site, should be easy to operate
9 the joint of the pipe should not be used with the left and right thread
10 pay attention to the design of pipe support
11 when assembling and dismantling pipeline, it is not appropriate to move the equipment
12 pay attention to the hysteresis of hydraulic and pneumatic equipment.
13 to avoid the hose is subject to additional stress
14 when the medium pressure in the hose is pulse, the hose should be fixed.
15 to consider the starting and stopping of the fuel supply
16 the inner overflow valve of the oil pump should not be used frequently.
17 cooling water pollution will reduce the cooling capacity
The 18 surface of the cooling water pipe to prevent condensation
19 to prevent the valve in the vibration of the hand wheel rotation
20 large aperture stop valve opening difficulties
21 to prevent the opening of the safety valve when the medium of wounding
Thirteen, frame structure design
1 reduced number of cores
2 avoid the use of core support to prevent leakage
3 to change the inner cavity structure to ensure the core iron strength and easy to clean sand
4 pay attention to the small size of the site
5 improve the casting cooling condition
6 simplified casting molding
7 improved structure, eliminating type core
8 to prevent deformation of casting frame
9 the structure of the throat opening should be strengthened
10 pay attention to strengthening the base of the torsional stiffness
11 the change of the casting for punching welding structure
12 will be changed to forging forging welding structure
13 to reduce the wall thickness, saving metal
Fourteen, the structure design of the guide rail
　
1 under normal circumstances should not adopt double V guide rail
2 the working platform supported by the guide rail, the driving force acting point should balance the resistance moment of the two guide rails.
3 the working table and the guide rail should be “ short in the upper ”
4 pairs of rectangular guide rail to consider the adjustment gap
5 when the temperature change of the guide rail is larger, the distance between the guide surface should not be too large.
6 the clamp plate of the guide rail is in good contact, stable and reliable.
7 pressure plate to have size boundaries
8 insert the steel guide rail should not be fixed with slotted head screws
9 insert adjustment should be no gap
10 oriented surface should be unchanged
11 insert should be loaded on the surface of the force
12 avoid casting defects
13 the bearing part of the guide rail should have a high stiffness
14 the screw of the fixed guide rail should not be inclined
15 avoid the influence of the guide rail when the screw is firmly fixed.
16 ball guide rail should have enough hardness
17 roller guide roller should not be too long
18 as far as possible to avoid the use of scraping
19 to prevent the rolling piece from rail, mounting and limiting device
20 reduce the adjustment of the installation of the guide rail
21 pay attention to the combination of the guide rail surface can be mutual research
Fifteen, spring structure design
　
1 spring due to the necessary adjustment device
2 helical compression spring should have a certain margin when the maximum working load
3 spring should be safe device
4 the combination of helical spring rotation should be the opposite
5 note that the helical torsion spring force direction
6 should pay attention to the plate spring pin wear and lubrication
7 ring springs should be considered the reset problem
8 springs should avoid stress concentration
9 automatic feeding of the spring to avoid each other