1、 ISO 2016 Plain bearings Hydrostatic plain journal bearings with drainage grooves under steady-state conditions Part 1: Calculation of oil-lubricated plain journal bearings with drainage grooves Paliers lisses Paliers lisses radiaux hydrostatiques avec rainures dcoulement fonctionnant en rgime stati
2、onnaire Partie 1: Calcul pour la lubrification des paliers lisses radiaux avec rainures dcoulement INTERNATIONAL STANDARD ISO 12167-1 Second edition 2016-09-15 Reference number ISO 12167-1:2016(E) ISO 12167-1:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in
3、Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
4、be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 12167-1:2016(E)Foreword iv Introduct
5、ion v 1 Scope . 1 2 Normative references 1 3 Bases of calculation and boundary conditions . 1 4 Symbols, terms and units . 3 5 Method of calculation 5 5.1 General . 5 5.2 Load-carrying capacity 6 5.3 Lubricant flow rate and pumping power . 8 5.4 Frictional power. 9 5.5 Optimization 10 5.6 Temperatur
6、es and viscosities 11 5.7 Minimum pressure in recesses 11 Annex A (normative) Description of the approximation method for the calculation of hydrostatic plain journal bearings .13 Annex B (informative) Example of calculation according to the method given in Annex A23 Bibliography .32 ISO 2016 All ri
7、ghts reserved iii Contents Page ISO 12167-1:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Ea
8、ch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Internatio
9、nal Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the differen
10、t types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall n
11、ot be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is i
12、nformation given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technic
13、al Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html. The committee responsible for this document is ISO/TC 123, Plain bearings. This second edition cancels and replaces the first edition (ISO 12167-1:2001), of which it constitutes a minor revision. ISO 12167 consists of t
14、he following parts, under the general title Plain bearings Hydrostatic plain journal bearings with drainage grooves under steady-state conditions: Part 1: Calculation of oil-lubricated plain journal bearings with drainage grooves Part 2: Characteristic values for the calculation of oil-lubricated pl
15、ain journal bearings with drainage groovesiv ISO 2016 All rights reserved ISO 12167-1:2016(E) Introduction Hydrostatic bearings use external lubrication to support pressure on the bearings; thus, are less prone to wear and tear, run quietly, and have wide useable speed, as well as high stiffness and
16、 damping capacity. These properties also demonstrate the special importance of plain journal bearings in different fields of application such as in machine tools. Basic calculations described in this part of ISO 12167 may be applied to bearings with different numbers of recesses and different width/
17、diameter ratios for identical recess geometry. Oil is fed to each bearing recess by means of a common pump with constant pumping pressure (system p en= constant) and through preceding linear restrictors, e.g. capillaries. The calculation procedures listed in this part of ISO 12167 enable the user to
18、 calculate and assess a given bearing design, as well as to design a bearing as a function of some optional parameters. Furthermore, this part of ISO 12167 contains the design of the required lubrication system including the calculation of the restrictor data. ISO 2016 All rights reserved v Plain be
19、arings Hydrostatic plain journal bearings with drainage grooves under steady-state conditions Part 1: Calculation of oil-lubricated plain journal bearings with drainage grooves 1 Scope This part of ISO 12167 applies to hydrostatic plain journal bearings under steady-state conditions. In this part of
20、 ISO 12167, only bearings with oil drainage grooves between the recesses are taken into account. As compared to bearings without oil drainage grooves, this type needs higher power with the same stiffness behaviour. 2 Normative references The following documents, in whole or in part, are normatively
21、referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3448, Industrial liquid lubricants ISO viscosity classification I
22、SO 12167-2:2001, Plain bearings Hydrostatic plain journal bearings with drainage grooves under steady-state conditions Part 2: Characteristic values for the calculation of oil-lubricated plain journal bearings with drainage grooves 3 Bases of calculation and boundary conditions Calculation in accord
23、ance with this part of ISO 12167 is the mathematical determination of the operational parameters of hydrostatic plain journal bearings as a function of operating conditions, bearing geometry and lubrication data. This means the determination of eccentricities, load- carrying capacity, stiffness, req
24、uired feed pressure, oil flow rate, frictional and pumping power, and temperature rise. Besides the hydrostatic pressure build up, the influence of hydrodynamic effects is also approximated. Reynolds differential formula furnishes the theoretical basis for the calculation of hydrostatic bearings. In
25、 most practical cases of application, it is, however, possible to arrive at sufficiently exact results by approximation. The approximation used in this part of ISO 12167 is based on two basic formulae intended to describe the flow through the bearing lands, which can be derived from Reynolds differe
26、ntial formula when special boundary conditions are observed. The Hagen-Poiseuille law describes the pressure flow in a parallel clearance gap and the Couette formula the drag flow in the bearing clearance gap caused by shaft rotation. A detailed presentation of the theoretical background of the calc
27、ulation procedure is included in Annex A. The following important premises are applicable to the calculation procedures described in this part of ISO 12167: a) all lubricant flows in the lubrication clearance gap are laminar; INTERNATIONAL ST ANDARD ISO 12167-1:2016(E) ISO 2016 All rights reserved 1
28、 ISO 12167-1:2016(E) b) the lubricant adheres completely to the sliding surfaces; c) the lubricant is an incompressible Newtonian fluid; d) in the whole lubrication clearance gap, as well as in the preceding restrictors, the lubricant is partially isoviscous; e) a lubrication clearance gap completel
29、y filled with lubricant is the basis of frictional behaviour; f) fluctuations of pressure in the lubricant film normal to the sliding surfaces do not take place; g) bearing and journal have completely rigid surfaces; h) the radii of curvature of the surfaces in relative motion to each other are larg
30、e in comparison to the lubricant film thickness; i) the clearance gap height in the axial direction is constant (axial parallel clearance gap); j) the pressure over the recess area is constant; k) there is no motion normal to the sliding surfaces. The bearing consists of Z cylindrical segments and r
31、ectangular recess of the same size and is supplied with oil through restrictors of the same flow characteristics. Each segment consists of a circumferential part between two centre lines of axial drainage grooves. With the aid of the above- mentioned approximation formulae, all parameters required f
32、or the design or calculation of bearings can be determined. The application of the similarity principle results in dimensionless similarity values for load-carrying capacity, stiffness, oil flow rate, friction, recess pressures, etc. The results indicated in this part of ISO 12167 in the form of tab
33、les and diagrams are restricted to operating ranges common in practice for hydrostatic bearings. Thus, the range of the bearing eccentricity (displacement under load) is limited to = 0 to 0,5. Limitation to this eccentricity range means a considerable simplification of the calculation procedure as t
34、he load-carrying capacity is a nearly linear function of the eccentricity. However, the applicability of this procedure is hardly restricted as in practice eccentricities 0,5 are mostly undesirable for reasons of operational safety. A further assumption for the calculations is the approximated optim
35、um restrictor ratio 1 = 1 for the stiffness behaviour. As for the outside dimensions of the bearing, this part of ISO 12167 is restricted to the range bearing width/bearing diameter B/D = 0,3 to 1, which is common in practical cases of application. The recess depth is larger than the clearance gap h
36、eight by a factor of 10 to 100. When calculating the friction losses, the friction loss over the recess in relation to the friction over the bearing lands can generally be neglected on account of the above premises. However, this does not apply when the bearing shall be optimized with regard to its
37、total power losses. To take into account the load direction of a bearing, it is necessary to distinguish between the two extreme cases, load in the direction of recess centre and load in the direction of land centre. Apart from the aforementioned boundary conditions, some other requirements are to b
38、e mentioned for the design of hydrostatic bearings in order to ensure their functioning under all operating conditions. In general, a bearing shall be designed in such a manner that a clearance gap height of at least 50 % to 60 % of the initial clearance gap height is ensured when the maximum possib
39、le load is applied. With this in mind, particular attention shall be paid to misalignments of the shaft in the bearing due to shaft deflection which may result in contact between shaft and bearing edge and thus in damage of the bearing. In addition, the parallel clearance gap required for the calcul
40、ation is no longer present in such a case. In the case where the shaft is in contact with the bearing lands when the hydrostatic pressure is switched off, it might be necessary to check the contact zones with regard to rising surface pressures. It shall be ensured that the heat originating in the be
41、aring does not lead to a non-permissible rise in the temperature of the oil.2 ISO 2016 All rights reserved ISO 12167-1:2016(E) If necessary, a means of cooling the oil shall be provided. Furthermore, the oil shall be filtered in order to avoid choking of the capillaries and damage to the sliding sur
42、faces. Low pressure in the relieved recess shall also be avoided, as this leads to air being drawn in from the environment and this would lead to a decrease in stiffness (see 5.7). 4 Symbols, terms and units Table 1 Symbols, terms and units Symbol Term Unit a Inertia factor 1 A lan Land area m 2 * A
43、 Relative land area * 1 A p Recess area m 2 b Width perpendicular to the direction of flow m b ax Width of axial outlet m b c Width of circumferential outlet m b G Width of drainage groove m B Bearing width m c Stiffness coefficient N/m c p Specific heat capacity of the lubricant (p = constant) J/kg
44、K C R Radial clearance / m d cp Diameter of capillaries m D Bearing diameter (D J : shaft; D B : bearing; D D J D B ) m e Eccentricity (shaft displacement) m f Relative film thickness f = h/C R 1 f en,i Relative film thickness at i 1 f ex,i Relative film thickness at i 1 F Load-carrying capacity (lo
45、ad) N F* Characteristic value of load-carrying capacity F* = F/(B D p en ) 1 F * Characteristic value of effective load-carrying capacity 1 F * Characteristic value of effective load-carrying capacity for N = 0 1 h Local lubricant film thickness (clearance gap height) m h min Minimum lubricant film
46、thickness (minimum clearance gap height) m h p Depth of recess m K rot Speed-dependent parameter 1 l Length in the direction of flow m l ax Axial land length m ISO 2016 All rights reserved 3 ISO 12167-1:2016(E) Symbol Term Unit l c Circumferential land length m l cp Length of capillaries m N Rotatio
47、nal frequency (speed) s -1 p Recess pressure, general Pa p Specific bearing load p = F/(B D) Pa p en Feed pressure (pump pressure) Pa p i Pressure in recess i Pa P i * Pressure ratio P i * = P i /P en 1 p i, 0 Pressure in recess i, when = 0 Pa P* Power ratio (P* = P f /P p ) 1 P f Frictional power W
48、 P p Pumping power W P tot Total power (P tot= P p+ P f ) W P * Characteristic value of total power 1 Q Lubricant flow rate (for complete bearing) m 3 /s Q* Lubricant flow rate parameter 1 Q cp,i Lubricant flow rate from capillary into recess 1 m 3 /s R cp Flow resistance of capillaries Pas/m 3 R lan, ax Flow resistance of one axial land Pas/m 3 R lan, c Flow resistance of one circumferential land Pas/m 3 R P, 0 Flow resistance of one recess, when = 0, R R Pas/m 3 Re Reynolds number 1 So Somme
