A method of obtaining a press-fit connection of hollow cylindrical parts
(57) Abstract:The method can be used to obtain press connection cylindrical parts used, for example, in devices for protection against vibration and shock. On the mating surfaces of the connected parts perform end-to-end lengthwise of the slot. Details are combined with the relative offset of the slots in the circumferential direction at an angleo= n45where n = 1,3,5,7. Then measure the actual load repressive and determine its deviation from the setpoint. Then adjust the load repressive by relative adjustment of the offset parts in the circumferential direction at an angle of 45°. This increases the fidelity of a given load repressive. 2 Il. The invention relates to the field of engineering, namely to methods for forging connections cylindrical parts used, for example, in devices for protection against vibration and shock.A known method of obtaining a press-fit connection of hollow cylindrical parts, including Assembly parts (SU 449798 A, 15.11.74, B 23 P 11/02).The disadvantage of this method is the lack of fidelity of a given load respres is giving the fidelity of a given load repressive.To solve the problem in the known method of obtaining a press-fit connection of hollow cylindrical parts, including Assembly parts on the mating surfaces of the connected parts perform end-to-end longitudinal slot, and the Assembly of parts is carried out with a relative offset of the slots in the circumferential direction at an angleo= n45where n = 1, 3, 5, 7, and then measure the actual load repressive, determine its deviation from the setpoint and adjust the load repressive by relative adjustment of the offset parts in the circumferential direction at an angle of 45o.Running through the longitudinal slots in both parts significantly reduces the radial rigidity of the press-fit connection. So there is the possibility of obtaining low values of efforts repressive at higher values of radial interference fit. Thereby the expansion of the range specified loads repressive with the increased accuracy of their playing. Each installed in forging the connection parts with a through longitudinal slot has a cross sectional shape of an ellipse with the greater axis passing through the slot. Therefore, when the combination of the slits of the Rog relative to each other on the 90oor 270othe area of contact decreases, radial force, and hence the force repressive (as confirmed by the experimental data). This allows through mutual reversal of the slots to provide an exact reproduction of a given load repressive.The invention is illustrated in the drawings.In Fig. 1 shows the idealized dependence of load repressive Npfrom the angle of reciprocal rotation slots.In Fig. 2 shows obtained from the graph of Fig. 1 dependence of correcting deviations N = NRF-Npofrom the corner corrective offsetto.
As can be seen from Fig. 1, the dependence of Np() is determined by the ratio:
Np= Npo+Nmcos2, (1)
where Npo- the value of the load repressive wheno= n45,
n= 1, 3, 5, 7;
Nm- the maximum deviation of the load repressive on the value of Npowhen = 0oand 180o;
-Nm- the maximum deviation of the load repressive on the value of Npowhen = 90 and 270o.The dependence of Np() is superimposed on the horizontal line Npo= const cosinusoid with amplitude N
N = Nmsin2to, (2)
to= 1/2arcsin(N/Nm); (3)
when n = 3, 7
N = -Nmsin2to, (4)
to= -1/2arcsin(N/Nm) (5)
The method is as follows.On the mating surfaces of hollow cylindrical parts perform a longitudinal slits.Assembly press-fit connection carried out as follows.Produce a press-fitting the bushing by means of an axial load or otherwise. While allowing relative displacement of the slits on the corner o= n45where n = 1, 3, 5, 7. As can be seen from Fig. 1, with the specified value load repressive Ner= Nro. Angleochoose depending on the design and other features press-fit connection.Choose the right value ofoit is very important, because practical dependencies may differ from the idealized shown in Fig. 1, 2 for explanation of the invention (for example, it is possible that N is the total control (for example, ). Determine the deviation of N = NRF-Ner= NRF-Npoand depending on its sign and magnitude to produce the adjustment of the value of Npthe relative corrective shift of parts in the circumferential direction at an angle toin the range 45. As follows from Fig. 1, 2 and relations (3), (5):
foro= 45oand 225oif N > 0, the correction shift is produced in the direction of increasing angle (to> 0), and if N < 0 in the direction of decreasing angle (to< 0);
foro= 135oand 315oif N > 0,to< 0, and if N < 0, to> 0.
Depending on the design and technological features press-fit connection correcting the shift details are carried out either in the assembled connection, or the connection apart, and after corrective shift gather again. If you want to implement with high accuracy given the efforts of repressive can be carried out several corrective shifts.The invention is illustrated by the following example.Press the compound containing two hollow cylindrical part with a longitudinal through slots used in the device for damping vibrations.Value o = 45oby application of axial force, the value of NRFwas measured by the method of  and was 5.3 kg. Was determined deviation N = 5,3 - 5 = 0.3 kg. Was calculated according to equation (3) the angular adjustment of the shift
< / BR>Made corrections Npadditional turn components on the 9oin the direction of increasing angle .
The use of the proposed method to provide the specified load repressive in wide range and with high accuracy. A method of obtaining a press-fit connection of hollow cylindrical parts, comprising an Assembly of parts, characterized in that the mating surfaces of the connected parts perform end-to-end longitudinal slot, and the Assembly of parts is carried out with a relative offset of the slots in the circumferential direction at an angleo= n45where n = 1, 3, 5, 7, and then measure the actual load repressive, determine its deviation from the setpoint and adjust the load repressive by relative adjustment of the offset parts in the circumferential direction at an angle of 45o.
FIELD: machine engineering, possibly manufacture of sealing envelopes of corrosion resistant steels of metal-plastic high-pressure bottles.
SUBSTANCE: method comprises steps of separately making metallic convex bottoms with cylindrical collar and backing ring. Thermal expansion factor of backing ring exceeds that of bottoms; outer diameter of backing ring provides close fit of bottoms onto it at 20°C; cooling preliminarily assembled backing ring with bottoms until cryogenic temperature; sliding bottoms on backing ring in cooled state until mutual touch of cylindrical collars of bottoms; heating assembly up to 20°C in order to provide close fit of backing ring in cylindrical collars of bottoms; welding bottoms along butt of assembly and then removing backing ring by chemical milling.
EFFECT: simplified process of making envelopes with enhanced mass characteristics.
2 cl, 4 dwg, 1 ex
FIELD: machine engineering, namely equipment for dismounting press-fit joints, possibly restoration of electric machines.
SUBSTANCE: apparatus includes housing with platforms for horizontal and vertical motions. Part to be dismounted is placed on horizontal motion platform and it is fed to stripping mechanism. The last is joined with vertical motion platform by means of fastening members and it is provided with adjusted grips supporting heating members with possibility of their axial movement. Heating members are in the form of nozzles for alternating feed of hot and cooled air.
EFFECT: reduced axial errors between dismounted part and stripping mechanism, lowered efforts for stripping parts.
5 cl, 5 dwg
FIELD: machine engineering, possibly restoration of articles operating at large cyclical loads and high temperature values.
SUBSTANCE: method comprises steps of cooling male part in liquefied nitrogen and introducing it into female part. Male part is made of refractory nickel alloy similar to that of female part. After equalizing temperature of assembly, it is heated till recrystallization temperature and subjected to isothermic soaking. It causes creation of structural and phase conversions in assembled parts.
EFFECT: improved quality of joints of parts.
1 ex, 1 tbl
FIELD: mechanical engineering.
SUBSTANCE: invention can be used in shaft-bushing interference. According to invention, shaft and bushing are made of material with similar physical and mechanical properties with projections in form of laser hardened paths. Pitch of parts is twice as great as their width. Paths are arranged at angle of 0-90° to axis of joint. Opposite paths of shaft and bushing are displaced relative to each other by width of part. In particular cases, paths can be arranged along ring lines lying in planes square to axis of joint, in starting lines parallel to axis of joint, or helical lines.
EFFECT: increased load-carrying capacity of joint.
4 cl, 4 dwg
FIELD: measuring technique.
SUBSTANCE: device comprises flexible measuring member mounted concentrically with respect to the bearing race and having strain gauges covered with casing and set on its surface. The device also has split bushing with conical outer side mounted for permitting cooperation of the inner side of the flexible member with the outer side of the bearing race to be tested. The flexible member is sectional and composed of two step thick-walled races provided with strain gauges, mounted on the bushing, and interconnected by means of a thread joint. The bushing has ring cylindrical recess centered in its outer surface. The inner surfaces of the smaller steps of the thick-walled races are conical, with cone bases arranged from the side of the large steps.
EFFECT: enhanced convenience of testing and reduced metal consumption.
FIELD: plastic working of metals, namely processes for forming butt welded seams on tubes at making tube studs of U-shaped tube bundles using effect of localized hot plastic deforming of welded seam and near-seam zones.
SUBSTANCE: method comprises steps of preliminarily working tube ends by expanding them from cylinder to cylinder; assembling tubes with use of mandrel and placing intermediate member of additive material between joined end surfaces of end portions of tubes sized by expansion and end surfaces of step ring. Welded seams are formed by argon-arc welding due to melting material of intermediate member at its both sides adjacent to tube ends. The intermediate member is heated up and it is subjected to hot radial squeezing while concentrating its initial deformation in surface layers according to position of ring steps, welded seams and near-seam zones on mandrel for providing size of their outer diameter equal to initial outer diameter of tubes.
EFFECT: improved quality of welded seams.
FIELD: railway transport; repair of rolling stock.
SUBSTANCE: invention relates to repair of load-bearing parts of vehicles, particularly, to repair of overspring beams of car bogies with inserts press-fitted into step bearings. According to proposed method, step bearing of overspring beam is heated, together with insert, to temperature exceeding 250°C. Inner surfaces of insert are cooled by blowing at velocity 1.1 times higher than velocity of heat exchange through surfaces in contact with step bearing to eliminate negative allowance between insert and outer bead of step bearing. To extract insert, it is expanded from inside by applying force. Device for implementing the method has body in form of disk to be arranged in step bearing with slots on side surface in which bellcranks 9 are fitted being driven by pneumatic cylinder, with claws for gripping the insert, central hole through which rod 16 of pneumatic cylinder passes to extract insert 40, with inner space designed for distribution of cooling compressed air among nozzles pointed to surfaces of insert.
EFFECT: increased efficiency when repair overspring beams, reduced energy consumption and labor input in process of repair.
3 cl, 4 dwg
FIELD: processes and apparatuses for assembling parts at tightness, possibly production and restoration of sleeves of sealing unit of turbo-compressor.
SUBSTANCE: method comprises steps of placing sleeve into embracing part at technological tightness; performing electric-contact heating of inner surface of sleeve and then deforming it by drifting for creating mounting tightness of sleeve and embracing part joint; smoothing roughness of inner surface of sleeve. Electric-contact heating and drifting of inner surface of sleeve are realized with use of duplex tool in the form of contact- heating tool and arranged behind it deforming- calibrating tool. Contact-heating tool provides heating of inner surface of sleeve in annular zone of contact with said contact-heating tool. Deforming- calibrating tool is mounted at tightness equal to 0.8 mm. In the result during one operation sleeve is pressed-in to embracing part, roughness of inner surface of sleeve is smoothed and inner surface of sleeve is strengthened at hardness 48 - 54 HRC3.
EFFECT: enhanced efficiency of assembling parts.
FIELD: machine building.
SUBSTANCE: invention is related to machine building and instrument making, and may be used in performance of machine assembly works. Method for interference fit of parts by means of press fitting with application of material that strengthens the joint includes partial press fitting of parts with measurement of press fitting force and their further additional press fitting. According to method partial press fitting of parts is carried out. Then material that strengthens joint is applied on free sections of joined surfaces of one or both parts. After that their further additional press fitting is realised.
EFFECT: simplification of assembly process and reduction of costs for joint strengthening.
FIELD: process engineering.
SUBSTANCE: external part inner surface is furnished with 2 to 5 mm-pitch teeth. Assembly is carried out to make a clearance between external and internal parts. Internal part is subjected to upsetting.
EFFECT: higher quality and strength of joint, simplified assembly.
4 dwg, 1 ex