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Practical technology * Transmission rear cover assembly bearing assembly technology transformation Yan Cangfeng (Shaanxi Fast Auto Transmission Group Co., Ltd., Xi'an 710077, China) Quality reduction workers labor intensity of the back cover assembly bearing mechanical press technology transformation. Through the analysis of several bearing assembly schemes, a better bearing press-fit technical modification scheme was selected, and the corresponding press-fit fixture design was introduced.
;bearing;assembly Automotive transmission rear cover assembly bearing assembly using manual intrusion, can not meet the requirements of modern enterprise development. Firstly, the hand-inserted bearing is used, and the strong impact force of the boring bar increases the damage of the bearing and the back cover casing and affects the assembly quality of the transmission. Secondly, the manual intrusion of the bearing is labor intensive, and the noise is large, causing environmental pollution. To this end, the rear cover assembly assembly was technically modified to assemble the bearing by mechanical press fitting.
1 bearing assembly description transmission rear cover assembly bearing assembly. The assembly process is as follows: a. The secondary box intermediate shaft assembly is placed in the positioning hole of the assembly tire; Place the synchronizer; Attached to the sub-box spindle, sub-box reduction gear and other accessories to install the rear cover housing assembly bearing. The three bearing centers are convex in a straight line. The glyph combination bearing 2 is higher than the bearing 1 (2 X æ° and in a sub-box spindle!
on flat surface. Manual assembly is to first install two bearings on both sides (for positioning), and then install the intermediate combination bearing. Pressing can be carried out by pressing two bearings on both sides and then pressing the intermediate combined bearing or three bearings at the same time.
2 Scheme Argument According to the characteristics of the rear cover assembly assembly, two kinds of press schemes are proposed, namely the three-beam four-column tie rod structure press (the scheme one Xiang C-shaped special press (scheme two) scheme one workshop back cover assembly The assembly line adopts circular track line, and several assembly trolleys circulate on the circular track line. On the basis of the existing circular track production line, the rear cover assembly trolley is modified to meet the needs of press positioning. The press adopts three-beam four-column rod Structure (such as), the fuselage sinks in the ground, so that the auxiliary table is level with the original line track. When the work is assembled, the assembled workpiece (shaft, shell and bearing) is loaded through the line track and pushed to the press. The table top limit rail keeps the car's original running track, the press machine elastic pre-positioning device is initially positioned, the car supports the bearing, picks up the assembly car, so that the small wheel is not under pressure, and the press positioning guide is secondarily positioned, and the press-fit bearing is pressed. When the device is assembled, the pre-positioning device is assembled and the trolley is sent to the next station.
2.2 Scheme 2 On the basis of the original circular track production line, the modified rear cover assembly trolley is a C-shaped press using a C-shaped special press, such as) when working, -18-automotive process and material table i plan one plan two press structure three beams Four-column rod structure press C-shaped special press four-column four-wheel assembly trolley C-shaped four-wheel assembly trolley assembly trolley car chassis side through the press limit rail; the bottom of the chassis has a predetermined hole; and the pre-positioning hole and trolley work The positioning position of the secondary positioning guide rod has a high position requirement, and the machining precision is high. The processing difficulty is high. The initial positioning of the trolley and the limiting device have a matching groove; the trolley and the clamp have a large clearance fit, and the secondary positioning is ensured by the clamp. Low processing accuracy requirements, low processing cost, low initial positioning, secondary positioning mechanism: elastic pre-positioning device, automatic limiter for disengaging positioning guide rod positioning assembly car cylinder limit device: sensor detects automatic limit after car, automatic Lifting the lifting and positioning device ejector positioning fixture presses and stresses the force of the assembled vehicle, and the assembly of the trolley is not required to install and construct the wire guide. The long installation period of the pit affects the direct installation of the production, does not need to damage the line body, does not dig the pit; the short installation period does not affect the production guide pole (4) press-fit positioning fixture trolley table assembly trolley guide column two limit rail ( Both sides) line body guide auxiliary table bearing (two rows * 'predetermined position device t plan one assembly car loaded with press-fit workpiece under the action of the linear body guide push the car to the press machine cylinder limit device after sensing the signal automatically Lock the assembly car for initial positioning. Place the bearing to start the press press. Lift the positioning cylinder to pick up the booster fixture, so that the car is not under pressure and the two ejector pins are used for secondary positioning. The press clamp press head is pressed down. The in-position head returns to the lifting positioning cylinder and the returning machine limit device automatically releases the press-fit to push the trolley to the next station.
Scheme 2: Comparison of the two schemes The comparison of the two schemes is shown in Table 1. Through comparative analysis of Table 1, comprehensive consideration of the positioning method of the press, the structure of the assembled trolley, the stress of the press, the processing cost and the installation and other factors Second, there are advantages such as simple and reliable positioning, low processing cost, short installation and construction period, and no influence on production.
3 press-fit fixture design and improvement of the tooling. Pressing adopts the method of lower positioning, which requires higher position requirements of the pressing head on the press and the positioning ejector of the lifting device below. When working, the automatic initial positioning of the press assembly, the lifting device, the cylinder, the lifting and positioning positioning rod, the secondary positioning pressing clamp of the lower positioning hole of the pressing fixture, and the three positioning holes on the pressing fixture are positioned between the two auxiliary boxes. The shaft and the auxiliary box main shaft ensure that the three shafts and their bearings have a certain degree of concentricity with the three upper pressing heads, and a large gap is left in the inner holes of the upper pressing head to ensure that the shaft does not interfere with the shaft during press fitting. . The press-fit jig is picked up and disengaged from the assembly trolley during press-fit, and the lower tooling plate is subjected to pressure/car without pressure.
4 Effect Analysis Scheme 2 The C-shaped special press and its assembly trolley have been officially put into production after a period of trial operation. After the production practice, the press is running well. The quality of the three bearings at the same time is stable, the labor intensity of the workers is also reduced, and the noise pollution caused by the manual intrusion into the bearing is also avoided.
(Responsible Editor Lin Xi) Development and design and research work of transmission process tooling.