外文原文
Structure improvement of construction winches
In recent years, construction winches have achieved great development, but due to various reasons, China's current production of construction hoists has varieties of problems such as disordered organization, structural differences in the same tonnage product transmission type, inconvenience of use , difficulty of repair ，the low rate of serialization generalization, standardization and so on.
A new type of JK1 winch has been produced by many construction machinery factories in the late 80’s. It has advantages of compact structure, reasonable layout, more advanced technical parameters reliable braking, convenient repairing flexible operation. But after years of production, there still exists some problems, for this, we performed the following improvements.
1. The improvement in sealing properties of transmission
In the JKI winch are found in the use of gear box oil leakage, site focused on the high speed shaft and the output shaft and the output shaft seal and cabinet. By the analysis of measurement, found the cause of oil leakage is bearing cover and between the output shaft and the felt is unreliable in sealing, the sealing effect can not reach the design requirements; and the high speed shaft and output shaft oil leakage is the main cause of hole inner and outer diameter of cylinder and coaxial degree did not meet the design requirements of accuracy, in order to achieve the design accuracy is required to increase grinding process and related process equipment, so as to increase the manufacturing cost. Therefore, we of the two structure was improved, the sleeve in the bore diameter on processing sealing groove, placed0type sealing ring, which reduces the outer diameter of the sleeve hole position accuracy and good sealing effect. In addition to the bearing cover, felt seal to 0type sealing can get good results.
2. The improvement of coupling type
the original design of JK1 hoist choose the tire coupling ,the coupling has the advantages of simple structure, good elasticity, torsion stiffness, damping capacity, compensation relativity great displacement; but the radial dimensions big, additional axial load, and the tire aging, in actual use, disassembly and assembly of complex, increased the difficulty of assembling. The current domestic production of couplings comparison, use a quincunx elastic coupling. It has the advantages of simple structure, good elasticity, torsion stiffness of small advantages, and small size, the axial load is small, simple disassembly and assembly, long service life of the elastic element. Through years of use，a quincunx elastic coupling safety, reliability than the original design of the tire coupling.
3. The improvement of gear materials
The original design of JKI hoist gear materials for ZG340 ~ 640 ( ZG55), poor processing technology, casting defects caused high scrap rate, high production costs. Using OT700-2to replace ZG55 with nodular cast iron, ductile iron gear. Check the contact strength and bending strength are better than the cast steel gear, casting scrap rate is greatly reduced, the machining process has been improved.
4. Improvement of control circuit
The original design by JKI hoist electromagnetic starter control circuit, poor safety, accident is frequent. According to GBI3329- 9I" building hoist safety regulations" and JG / T503I - 93" building hoist design standard", is a new design. The new design of the electric control box with a main contactor and a pair of motor control contactors， relays the other heating for overload protection, control the button box, the realization of the remote operation, the electronic control box in the reserved wiring terminal, and can be connected in series, lower limit and limit device. In order to realize and I plant the production of SSI00 lifting machine, also increased the phase sequence relay. The improved electric control box can realize the quick stop short circuit, overload and pressure loss, zero, broken phase protection, enhance the safety and reliability, improve the overall technical performance, users establish a good reputation, improve my plant hoister in market share.
5. The gear transmission mechanism with small tooth difference
Use of the gear transmission mechanism with small tooth difference superiority can improve and enhance the construction machinery and equipment of the transmission structure technical performance, the planetary gear drive with small teeth difference is applied to building hoist engine power transmission system, is to make the traditional hoist volume is reduced, optimize a structure, reduce cost, improve performance in an effective way, which has broad prospects
5.1 The correct gear meshing transmission under the condition of selecting the modification coefficient.
The correct gear meshing transmission under the premise, in the design of few teeth difference speed reducing mechanism by changing the internal, external gear tooth number can get different drive ratio, if the internal gear tooth number ( Z 2) unchanged, the outer gear tooth number ( Z 1) is bigger, the tooth number difference ( Z1) smaller, the transmission ratio is bigger. But for the tooth top height h a! = 1, the original tooth angle!0 =20standard internal gear pair, in Z1to a certain extent because of internal and external gear tooth profile to an eclipse, not according to the original design of the center distance of the assembly. In Z1 very hour gear side can still normally meshing transmission, the existing two ways to follow; one is to reduce the tooth top height, using short tooth shape to remove the tooth outline overlap; two is through the selection of proper modification coefficient, increase the internal gear tooth width, reduced thickness from top gear, tooth gap eliminating tooth outline overlap. The implementation of the above two methods can be adopted at the same time, in order to achieve the best effect of meshing transmission. Notably, when the internal and external gear pair with short gear and internal gear are changed, the tooth thickness, tooth height, length of cable, center distance, the meshing angle and meshing performance are also changed, from inside and outside the choice of gear modification coefficient is key.
5.2 The reasonable range of displacement gear
Gear should ensure the addendum coefficient Se / M=0.4, and the tooth top still for tooth profile. Generally less tooth difference construction hoist technical parameters can meet the requirements， it can be omitted in inspection
5.3 internal gearing with interference
According to the transmission ratio and strength calculation conditions of the small tooth difference transmission pair of main technical parameters, can ensure its smooth installation and the normal operation of the key is to consider other without interference conditions can also meet the requirements.
（1）Interference in Z 2under the condition of Z 1is larger than a certain value, the interference does not occur. As a result of less tooth difference gear drive gear tooth number is closer to1, and Z has been greater than the incidence of inv interference limit value, so this condition without checking.
（2） the transition interference because of slotting internal gear slotting cutter of the top than the normal tooth height of a tooth tip clearance height, and few teeth difference internal gear pair made of short tooth for tooth ( h a! = 0.8), so both inner and outer tooth gear transition is the possibility of interference are small, actual node other teeth touch design can be from checking.
（3）Addendum together assembly
Internal gear pair in order to prevent the occurrence of those shown in Figure 1, the node of the tooth top touching each other, ensure the normal operation, to make internal gear pair of nodes each tooth top radial clearance should be reasonable, inspection.
6. Notes about processing
Small tooth difference transmission construction hoist in manufacture and other modes of transmission winch has many different, should be noted.
6.1 Ways of selection
JK1 type construction hoist is used in a pin shaft type gear transmission mechanism with small tooth difference, the selection of parts materials should not only consider the use of mechanical equipment requirements, processing conditions, but also to take into account the selected materials in the technical performance and cost reasonableness. comparison of pen. Thinking of that the main drive shaft, planetary gear and other parts can choose45 steel and 40Cr steel, pin, shaft sleeve can choose Gcrl5, pin45, pin shaft sleeve to switch to 40Cr steel can meet the using requirements; the output shaft can be ZG45or ZG55, internal gear should be chosen,Tl20or l T60(70,80) - 2; the support and the reel can choose HT200, so that not only can reduce the cost and ensure the mechanical properties. Notable is must carry on the reasonable heat treatment, in order to give full play to the selected material with excellent properties, for casting, forging, welding pieces must be aging treatment, to eliminate the internal stress, improve the processing performance.
6.2 Precision should be appropriate.
Proper machining accuracy is to ensure that product quality performance. Small tooth difference transmission has the advantages of compact structure, form and position tolerance requirements higher, except the shaft diameter tolerances.
（1）General coupling piece can be routinely asked to choose should also pay attention to the following points, gear machining accuracy not less than Gbl0095 - precision, the tooth thickness deviation based on clearance requirements in FL or GM flexible options, such as 877HK etc..
（2）A planet wheel pin hole, the output shaft and a pin shaft frame pinhole aperture tolerances can be selected by H8, pin shaft diameter according to the H7, pin shaft sleeve outer diameter can be selected according to f 7. Notable is the three above the coaxial error of hole distribution error should be as small as possible, general pin hole adjacent error. With the cumulative error tolerances are under the control of the 004mm and0 08mm within, or it may cause large noise, affect the transmission performance.
（3）A planet wheel pin hole of nominal size in addition to the pin shaft sleeve outer diameter and two times the eccentricity should also increase the appropriate amount of compensation, is introduced to remedy the pin shaft, pin, sets of processing and assembly error, is too small to improve related parts processing precision, otherwise difficult assembly, operation of case; too large may lead to pin loads are easily made into shaft break, or sets of crack.