CN102485635B - Method for controlling kinematic accuracy of pallet fork - Google Patents
Method for controlling kinematic accuracy of pallet fork Download PDFInfo
- Publication number
- CN102485635B CN102485635B CN 201010572773 CN201010572773A CN102485635B CN 102485635 B CN102485635 B CN 102485635B CN 201010572773 CN201010572773 CN 201010572773 CN 201010572773 A CN201010572773 A CN 201010572773A CN 102485635 B CN102485635 B CN 102485635B
- Authority
- CN
- China
- Prior art keywords
- pallet fork
- orienting lug
- contact surface
- kinematic accuracy
- motor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention discloses a method for controlling the kinematic accuracy of a pallet fork, which belongs to the control field of mechanical motion. The method is characterized in that the pallet fork can be more stably braked by transforming the mechanical structure of a guide block, changing a lubrication mode and changing a motion control mode. With the method, the kinematic accuracy of the pallet fork can be favorably controlled, the phenomena that the pallet fork shakes between left and right, is subjected to clamping stagnation, creeps and the like when moving are overcome, the pallet fork is guaranteed to stably move and accurately position, the requirement that a dimensional tolerance is 0.17-0.22mm is satisfied, the fault incidence is greatly lowered, the stable continuity of production is improved, an extremely favorable condition is created for improving the production efficiency, and the labor intensity of maintenance personnel is lightened. The method for controlling the kinematic accuracy of the pallet fork is simple to operate and has the advantages of small input, good industrial application value and good popularization and application prospect.
Description
Technical field
The invention belongs to mechanical movement control field, relate to a kind of method of controlling the pallet fork kinematic accuracy.
Background technology
At present, overhead tiered warehouse facility owing to save the space, be convenient to statistics, access is convenient and swift, reduce labour intensity, save advantages such as human cost is extensive use of.Piler requires to have the function of single-direction and dual-direction double or single station access material as the access arrangement of key.Requirement has designed multi-class workload retractor device (hereinafter to be referred as pallet fork) based on this kind, can realize above-mentioned functions.Pallet fork commonly used mainly is made up of lower fork, middle fork, last fork, transmission component, power transmission assembly.
Because pallet fork belongs to high-accuracy parts, in the operational process locating accuracy require very high, so designed the registration device of forming by chute, bearing and the orienting lug of fork body.Its centre bearer mainly realizes respectively pitching the location up and down of body, orienting lug mainly realize respectively pitching body about the location.For prevent pallet fork when operation double swerve, clamping stagnation, creep, need reprocessing after all orienting lugs assemblings, to guarantee the planeness and the size tolerance requirements of orienting lug.Yet, because orienting lug is a nylon material, be subjected to the influence of ambient temperature factor and expand with heat and contract with cold, cause distance between orienting lug and the pallet fork contact surface to increase or dwindle, can not satisfy dimension limit requirement (0.17～0.22mm), pallet fork double swerve, clamping stagnation, creeping phenomenon when operation appear, reduced the accuracy of positioning of pallet fork, rate of breakdown is higher, has greatly influenced the operating efficiency of piler, can not reach the design original intention of orienting lug.
Summary of the invention
The object of the invention is to provide a kind of method of controlling the pallet fork kinematic accuracy.The present invention makes its temperature traverse that conforms by changing guide block structure and mode, reaches the object of the invention.
The principle of the invention: when temperature was high, the distance between orienting lug and the pallet fork contact surface reduced (less than 0.17mm), and friction force f increases, and need to satisfy: the power F that pallet fork obtains is greater than friction force f.As shown in Equation 1: formula 1:F＞f=
, shown in formula 1, reduce the positive pressure N of contact surface, reduce the coefficientoffriction of contact surface, increase pallet fork power F, the design original intention that can satisfy the pallet fork accurate positioning, operates steadily.When temperature was low, the distance between orienting lug and the pallet fork contact surface increased (greater than 0.22mm), needed to reduce the distance between orienting lug and the pallet fork contact surface, satisfied the requirement of dimension limit.
Concrete technical scheme is as follows: at first with vertical punching of contacted orienting lug one side of pallet fork, make the hole become the row, column rectangular distribution, internal stress is disperseed to each hole, change the internal stress defective outside or that inwardly disperse that caused because of temperature traverse originally, formation is with variation of temperature, each hole increases or dwindles, and can greatly reduce the lip-deep phenomenon of expanding with heat and contract with cold of orienting lug.When ambient temperature is high, reduce the positive pressure of contact surface, prevent catching phenomenon; When ambient temperature is low, reduce the amount of contraction of contact surface, prevent the double swerve phenomenon, satisfy the requirement of the dimension limit of orienting lug.And in the hole of orienting lug, inject lubricating oil, overcome the defective of easily the contact surface lubricating oil being taken away when original pallet fork moves, this improvement can make the lubricating oil in the orienting lug hole continue to replenish to contact surface, make contact surface keep certain thickness oil film, prevent the increasing of contact surface friction coefficient, skin friction force minimizes when keeping motion.
Pallet fork need in time stop, accurate location in motion process, thus require driving motor near stopping locating point in the very little scope with very low speed operation, prevent the inaccurate phenomenon in the location of causing stopping distance length to cause because of the speed height.In order to control the speed of pallet fork, the general mode that adopts frequency converter timing, however under frequency below the 5Hz and low cruise situation, the maximum torque of motor will sharply reduce, when ambient temperature is high (the contact surface friction force can strengthen), can not overcomes friction drag and cause and creep and catching phenomenon.The present invention changes original in the modes of 45Hz to 3.5Hz two speed conversions, steadily reduce frequency gradually, make the maximum torque change curve of driving motor mild, and at last 10mm, frequency is reduced to 3.5Hz, rely on the inertia of motor to overcome bigger friction drag, accurately locate at locating point.
The invention has the advantages that, at the existing pallet fork orienting lug temperature traverse ability that conforms, make the pallet fork can not smooth running, the inaccurate problem in location, the present invention has carried out comparatively detailed research and test, by transforming the structure of orienting lug, the operation control method that changes pallet fork has been realized the object of the invention.This method has enlarged the range of temperatures that orienting lug adapts to, and is suitable for-10 ℃～50 ℃.Operation result shows: phenomenons such as this method overcome pallet fork when operation double swerve, clamping stagnation, creep, guaranteed the smooth operation of pallet fork, accurate positioning, satisfy the requirement of dimension limit 0.17-0.22mm, greatly reduced rate of breakdown, improved the steady and continuous of producing, created very advantageous conditions, alleviated maintainer's labour intensity for promoting production efficiency.This invention is simple to operate, and less investment has good industrial application value and popularizing application prospect.
Description of drawings
Fig. 1: internal stress figure before and after orienting lug is transformed, (a) is the internal stress scheme drawing before transforming among the figure, (b) is improved internal stress distribution scheme drawing;
Fig. 2: the present invention transforms back guide block structure scheme drawing, and 1 is orienting lug among the figure, and 2 is through hole; 3 are gib block installation screw;
Fig. 3: the mechanical specialities figure of motor under the different frequency speed governing, transverse axis M is a motor output torque among the figure, longitudinal axis n is a motor speed, Mm is the motor maximum torque, curve f1 is the mechanical characteristics of motor under the 45Hz, curve f5 is the mechanical characteristics of motor under the 4.5Hz, and curve f6 is the mechanical characteristics of motor under the 3.5Hz;
Fig. 4: mechanical friction resistance is with the variation diagram of ambient temperature, transverse axis M is a friction drag moment among the figure, longitudinal axis T is an ambient temperature, and M2 is the cooresponding friction drag moment of highest temperature T2 in the range of temperatures, and M1 is the cooresponding friction drag moment of minimum temperature T1 in the range of temperatures;
Fig. 5: mechanical characteristics of motor and load range overlay chart, D is the point of crossing of minimized friction resistance torque curve and f6 curve among the figure;
Fig. 6: motor is maximum torque sudden change curve and friction drag moment scope overlay chart on each position under the height two speed control molding formulas, initial point O is the pallet fork locating point among the figure, transverse axis M is a motor torque, longitudinal axis L is the distance of pallet fork and locating point, M1 and M2 are friction drag moment scope curves, and Mm is a motor maximum torque sudden change curve;
Fig. 7: the design sketch behind the mild maximum torque sudden change curve;
Fig. 8: use the range of temperatures that adapts to behind the present invention and enlarge design sketch.
The specific embodiment
The present invention is done describe in further detail below in conjunction with accompanying drawing and concrete research process, implementation method.
Embodiment
1, transforms guide block structure, reduce the deformation that orienting lug causes because of expanding with heat and contract with cold
After finding the pallet fork catching phenomenon, the present invention once considered the contact surface of grinding orienting lug, and this by analysis job operation can not guarantee the planeness of contact surface, also only was to adapt to current ambient temperature.Do not occur catching phenomenon if ensure temperature when high, will cause when temperature is low distance between the contact surface to exceed the upper limit of dimension limit, cause the double swerve amount of pallet fork to strengthen.The range of temperatures translation up or down that this job operation just adapts to orienting lug, and can not enlarge the range of temperatures that orienting lug adapts to, the present invention determines to transform the structure of orienting lug for this reason.The present invention has done two kinds of reforming modes: first kind is groove milling on contact surface, and second kind is to punch on contact surface, and does experiment respectively.Experimental result shows, second kind of reforming mode is better, trace it to its cause is because groove milling can not effectively change orienting lug in-to-in stress direction on contact surface, and on the orienting lug contact surface, punch, the internal stress direction is disperseed to the center in hole, thereby the hole is increased with variation of temperature or dwindle, greatly reduce the lip-deep phenomenon of expanding with heat and contract with cold of orienting lug.Can be understood as the coefficient of expansion that on contact surface, has reduced orienting lug, enlarged the range of temperatures that orienting lug adapts to, satisfy the requirement of the dimension limit of orienting lug.Shown in accompanying drawing one, stress F1 in figure (a) is decomposed into F1, F2, F3 in (b), F1 is reduced significantly, thereby greatly reduced the phenomenon of expanding with heat and contract with cold on orienting lug surface.
Because of on contact surface, punching, can reduce effective area of contact of contact surface.In order to ensure the positioning action of orienting lug, through overtesting, effectively area of contact reduces and can not surpass 25%.Preferably: on the orienting lug contact surface of 50 * 24mm, the diameter in hole, distribution and quantity are shown in accompanying drawing two: the quantity in hole is 11, and diameter is 5mm, both meets design requirement, and exceeds again to reduce effective area of contact; The hole be distributed as triplex row, each hole is staggered evenly distributed, and internal stress is uniformly dispersed.
2, change the contact surface lubricating method, effectively prevent the increase of surface friction coefficient
Before not transforming orienting lug, lubricating oil can only spread upon the contact surface surface, forms the thin oil film of one deck.Along with the operation of pallet fork, little by little the lubricating oil of contact surface to be taken away, the oil film attenuation that makes contact surface so, makes the friction coefficient of contact surface strengthen gradually until being zero easily, increases the friction drag of contact surface.After the present invention transforms orienting lug, coating lubricating oil on the orienting lug contact surface again, simultaneously lubricating oil is injected the hole of orienting lug, along with the extruding of pallet fork to orienting lug, lubricating oil in the hole can replenish to contact surface, compensation pallet fork dragged lubricant remains the thickness of contact surface oil film, the minimizing of the face friction coefficient of keeping in touch.
3, change the motor operation control method, the motor torque of control diverse location
In order to ensure the smooth operation of pallet fork, need motor (electric machine frequency is 45Hz) operation at a high speed when starting, enough big detent torque is provided, and operation fast; The low cruise during location (electric machine frequency is 3.5Hz) for avoiding can't accurately locating at locating point because of the speed inertia of motor, adopts frequency converter timing pattern control motor speed usually.The mechanical specialities of motor when frequency control is shown in accompanying drawing three: f1 is the mechanical specialities under the 45Hz, and f6 is the mechanical specialities under the 3.5Hz.And the temperature variant scope of pallet fork friction drag moment is shown in accompanying drawing four.
Mechanical specialities and the friction drag moment temperature variant scope of motor when the frequency control is superimposed, form the scheme drawing that motor torque under the different frequency shown in the accompanying drawing five overcomes friction drag moment scope.From accompanying drawing five as can be seen, when electric machine frequency is 3.5Hz, can't overcome maximum friction resistance torque in the range of temperatures.And vector frequency converter or the voltage when heightening low frequency etc. all are the methods that adopts when overcoming than the heavy load resistance in order to start, speed is to increase gradually, what motor torque was done is positive interaction, and in the pallet fork frequency conversion moderating process, speed is to reduce gradually, and low regime increases moment can cause stroke to braking, even because the excessive braking effect that causes of motor torque is bad, thereby make the location unstable, what bigger torque was done at glancing impact is counteraction.So should not adopt said method.
The present invention changes motor (from 45Hz to 3.5Hz) maximum torque of (with the distance of locating point) on diverse location in frequency conversion moderating process, in conjunction with the accompanying drawings four, plot the maximum torque variation diagram, shown in accompanying drawing six: as can be seen, early suddenling change with locating point larger distance motor maximum torque, less than friction drag moment, the merit that motor self kinetic energy can not overcome friction be done (motor inertia can not overcome long frictional distance).As shown in Equation 2:
Formula 2:
Motor enters low regime (motor stall) when motor self kinetic energy is zero, can not arrive locating point, and this is that the physics of catching phenomenon is described.
The present invention carries out the Mm curve mild on the short distance of distance locating point, shown in accompanying drawing seven, making electric machine frequency at the L1 place is 3.5Hz, enters the motor maximum torque less than friction drag moment district, makes motor kinetic energy
, overcome the friction drag of last distance L 1 by the inertia of motor, eliminate the pallet fork catching phenomenon, can reduce impact simultaneously to braking.
The principle of the invention is, on the L1 segment distance, utilizes friction drag that the brake action of motor is braked in advance, and this moment, the effect of friction drag was a positive interaction, and prerequisite is a motor kinetic energy
, according to above-mentioned principle and through test, determine that frequency converter timing is following three kinds of situations:
When the distance of pallet fork position and locating point greater than 100mm, the frequency converter output frequency is 45Hz;
When the distance of pallet fork position and locating point less than 10mm, the frequency converter output frequency is 3.5Hz;
When the distance of pallet fork position and locating point at 100mm between the 10mm, frequency converter output frequency Y is shown in the formula 3:
Formula 3:Y=(L-10) ÷ (100-10) * (45-4.5)+4.5
=(L-10)?÷90×40.5+4.5
=(L-10)?×0.45+4.5；
Formula 3 shows that between the 10mm, geometric ratio changes the frequency converter output frequency with the variation of position at 100mm, and between the 10mm, minimum frequency is 4.5Hz at 100mm, ensures at this interval motor torque greater than friction drag moment.L1=10mm, the mechanical characteristics of motor during 4.5Hz is seen the f5 in the accompanying drawing three.
Overcome under the condition of maximum friction resistance torque M2 satisfied, if ambient temperature reduces, when friction drag moment drops to M1,10mm in the end, motor stabilizing operates in the joining of f6 curve shown in the accompanying drawing five and M1 line, and this moment, friction drag moment and motor torque equated, glancing impact only needs except that the kinetic energy of motor own, this moment, motor was very little to the momentum of braking, satisfied the requirement of stable braking fully.
4, the effect that reaches behind application the present invention is shown in figure eight:
Before using the present invention, the range of temperature of adaptation is T1;
After transforming guide block structure, the range of temperature of adaptation is T2;
After changing lubricating method, the range of temperature of adaptation is T3;
After changing mode, the range of temperatures upper limit has been enlarged T4, the range of temperature of adaptation is T5;
Behind overall application the present invention, under the prerequisite that satisfies the installation dimension tolerance,, solve the pallet fork catching phenomenon fully, prevent pallet fork double swerve phenomenon simultaneously, reached the object of the invention along with the expansion of adaptive temperature scope.
Claims (2)
1. a method of controlling the pallet fork kinematic accuracy is characterized in that, has carried out following technological improvement: (1) transforms guide block structure: punch on the orienting lug contact surface, its internal stress is disperseed to the center in hole; Simultaneously, the diameter of control punch, quantity and distribution ensure that the minimizing of effective area of contact is no more than 25% of orienting lug contact surface; (2) change orienting lug contact surface lubricating method: in its mating surfaces coating lubricating oil, simultaneously lubricating oil is injected the hole of orienting lug, by the keep in touch thickness of face oil film of motion extruding, the minimizing of the face friction coefficient of keeping in touch; (3) change movement control mode: when the distance of pallet fork position and locating point greater than 100mm, the frequency converter output frequency is 45Hz; When the distance of pallet fork position and locating point less than 10mm, the frequency converter output frequency is 3.5Hz; To between the 10mm, the frequency converter output frequency changes with variation geometric ratio between 45Hz-4.5Hz of position at 100mm.
2. a kind of method of controlling the pallet fork kinematic accuracy as claimed in claim 1 is characterized in that, on the orienting lug hole be distributed as triplex row, each hole is staggered evenly distributed, the aperture is 5mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010572773 CN102485635B (en) | 2010-12-04 | 2010-12-04 | Method for controlling kinematic accuracy of pallet fork |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010572773 CN102485635B (en) | 2010-12-04 | 2010-12-04 | Method for controlling kinematic accuracy of pallet fork |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102485635A CN102485635A (en) | 2012-06-06 |
| CN102485635B true CN102485635B (en) | 2013-07-31 |
Family
ID=46151212
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201010572773 Active CN102485635B (en) | 2010-12-04 | 2010-12-04 | Method for controlling kinematic accuracy of pallet fork |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102485635B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3894350A4 (en) * | 2018-12-14 | 2022-09-07 | Cascade Corporation | Telescoping/weighing fork combination |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0277782A2 (en) * | 1987-02-04 | 1988-08-10 | Cascade Corporation | Load-lifting mast especially adapted for use with automatically-guided vehicles |
| WO2006003248A1 (en) * | 2004-07-06 | 2006-01-12 | Rocla Oyj | Forklift mast |
| CN1986377A (en) * | 2005-12-23 | 2007-06-27 | 斗山英维高株式会社 | Control system and method for electric-powered forklifts |
| CN101109941A (en) * | 2007-08-30 | 2008-01-23 | 上海精星仓储设备工程有限公司 | Method for fast accurate locating and stepless speed regulation of stacker |
-
2010
- 2010-12-04 CN CN 201010572773 patent/CN102485635B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0277782A2 (en) * | 1987-02-04 | 1988-08-10 | Cascade Corporation | Load-lifting mast especially adapted for use with automatically-guided vehicles |
| WO2006003248A1 (en) * | 2004-07-06 | 2006-01-12 | Rocla Oyj | Forklift mast |
| CN1986377A (en) * | 2005-12-23 | 2007-06-27 | 斗山英维高株式会社 | Control system and method for electric-powered forklifts |
| CN101109941A (en) * | 2007-08-30 | 2008-01-23 | 上海精星仓储设备工程有限公司 | Method for fast accurate locating and stepless speed regulation of stacker |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102485635A (en) | 2012-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104578562B (en) | Large-stroke multi-section linear actuator mechanism | |
| CN101130413A (en) | Method for controlling speed increase and reduction of high speed positioning movement of paper pulling device of paper cutter | |
| KR20120058150A (en) | Cylinder bore formed with oil pocket | |
| CN105328692A (en) | Telescopic device | |
| CN211202621U (en) | Isolator formula does not have little texture cylindrical roller bearing in holder surface | |
| CN102485635B (en) | Method for controlling kinematic accuracy of pallet fork | |
| CN103921133A (en) | Novel linear rolling and sliding composite guide rail pair | |
| CN105932902A (en) | J-type structure precise piezoelectric stick-slip linear motor and drive method thereof | |
| CN102321790B (en) | Nanometer modifying apparatus of metal material surface | |
| Bogajevskiy et al. | Selection of methods for modernizing the regulator of the rotation frequency of locomotive diesels | |
| CN103611793A (en) | Multi-module multi-directional high frequency vibration hot forming die | |
| EP3115654B1 (en) | Piston ring configured to reduce friction | |
| CN102506000A (en) | Pressure lubricating integral barrel-shaped tappet device | |
| CN101758631A (en) | Electromagnetic lead screw driving type precise-punching presser | |
| Zhan et al. | Investigation on the application of YAG laser texturing technology to the cylinder wall of auto engine | |
| CN201619254U (en) | Electromagnetic screw rod drive type fine blanking press | |
| CN102593022A (en) | Cross rolling needle guide pair | |
| CN202071396U (en) | Sealed height regulating device of precise punching hydraulic machine | |
| CN102601404B (en) | A kind of self-centering fast fixture | |
| CN203171249U (en) | Skidding combining guiding rail pair with adjustable gap | |
| US10077838B2 (en) | Piston ring configured to reduce friction | |
| CN101654727B (en) | Equal channel corner extrusion preparing method for preparing high-performance metal materials based on multi-pair wheel drive | |
| US9816457B2 (en) | Internal combustion engine and lubrication structure thereof | |
| JP5174121B2 (en) | Roller screw | |
| CN102886686A (en) | Beam used for vertical lath |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP02 | Change in the address of a patent holder |
Address after: 450000 Yulin South Road, Henan, Zheng Dong, No. 16 South Road, Zhengzhou Patentee after: China Tobacco Henan Industrial Co., Ltd. Address before: 450006 No. 29, agricultural East Road, Henan, Zhengzhou Patentee before: China Tobacco Henan Industrial Co., Ltd. |