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 Notherefore, the adjustment efforts of repressive can only be done within 90o. From the graph of Fig. 1 shows, that depending on the magnitude of the force repressive within 90oor decreases from maximum to minimum (when n = 1, 5), or increases from minimum to maximum (when n = 3, 7), passing through the average value at =oevery 45o. Therefore, the Assembly is press-fit connection must be carried out with an initial mutual offset of the slots in the angle = n45(where n= 1, 3, 5, 7), which will then allow by increasing or decreasing the angleowithin 45oto adjust (increase or decrease) the resulting Assembly load repressive.

In Fig. 1 for the case of an Assembly of parts with initial mutual offset of the slots in the angle o= 145o= 45oand the specified value the efforts of repressive Ner= Nroshows the resulting Assembly actual value the efforts of repressive N'RF> Nroand NRF< Nroand the corresponding actual deviations which should then decrease (N 0) by mutual adjustment of the shifting parts on the angletoto increase or decrease the angle of aotowithin 45- easily obtained from the expression (1). Subtracting from the left and right sides of the expressions (1) the value of Nroand considering thatto=o- = n45- where n = 1, 3, 5, 7, 'll get:

N = Nmsin2to, (2)

where

to= 1/2arcsin(N/Nm); (3)

when n = 3, 7

N = -Nmsin2to, (4)

where

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, [4]). 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 [4] 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.

 

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