LBT PROJECT 2x8.4m TELESCOPE
	TECHNICAL SPECIFICATION OF AZIMUTH RADIAL BEARING
	Doc. 401e046/B Date: September 21st, 1998 Prepared and Approved By: G.MARCHIORI/EIE

The AZIMUTH RADIAL BEARING is an element composing the LBT Project.

The aim of the LBT (Large Binocular Telescope) Project is to realise a telescope having two mirrors of 8.4 m diameter, to be installed at Mount Graham in Arizona (Fig. 1)(ref. dwg. No. 407e001c).

The AZIMUTH RADIAL BEARING represents the radial guidance of the Azimuth axis of the Telescope Pier.

The bearing is especially engineered in order to reduce the number of high precision mating parts, simplify erection and assure a high overall accuracy.

The supply of the AZIMUTH RADIAL BEARING includes:

• execution of all workshop drawings and Part Lists, based upon the design drawings included in the Request for Proposal;
• preparation of the Manufacturing Plan;
• selection and purchase of all materials, components, etc.
• preparation of all procedures and methods to execute the critical operations of the manufacturing;
• fabrication of all components;
• fabrication and/or purchase of all tools, necessary for the manufacturing and/or assembly and packing;
• painting or surface treatment;
• performance of checks and tests;
• packing;
• drawing up of the inspection and check documentation.

The main performance characteristics of the AZIMUTH RADIAL BEARING are the following:

• sustain the radial loads;
• grant the minimum radial clearance
• grant the axial freedom
• grant an adequate radial stiffness
• grant a smaller friction torque

The useful lifetime of the telescope is expected to exceed 25 years.

The contractor shall take into account of all aspects which could limit the lifetime of the supply (in particular the seal).

He shall also contain the number of maintenance interventions, supply adequate access for maintenance operations and minimise risks of damage, loss and injury to personnel and the telescope from telescope maintenance operations.

This chapter defines the natural and induced environmental conditions the telescope and subassemblies will encounter during its lifetime.

• Storage temperature: -30 to +50°C
• Operating temperature: -20 to +25°C
• Storage pressure: 500 to 750 Torr
• Operating pressure: 500 to 600 Torr
• Storage humidity: 5 to 80%
• Operating humidity: 5 to 95%
• Maximum operating windspeed: 80 km/h
• Maximum observing windspeed: 120 km/h
• Survival windspeed: 150 km/h
• Altitude 3250 m a.s.l.

Scope of the present chapter is to introduce the main characteristics of the supply from a manufacturing point of view.

The contractor shall fabricate all parts, equipment, components and materials of the AZIMUTH RADIAL BEARING in accordance with the requirements indicated in the present Technical Specification, pertinent drawings and Proposal documents.

Subsequent to fabrication, but prior to packaging the materials, the contractor shall store, at its sole expenses, all components, materials and equipment in manner that will reasonably protect such components, materials and equipment against loss or damage.

The bearing inner and outer diameter and the borehole are machined with tolerances indicated in dwg. n. 460e001b and defined with the contractor.

After working, these dimensions will have to be measured and the measurement protocol will have to be transmitted to LBT P.O. (LBTC Technical Representative). LBT P.O. will make these measurements available to the manufacturer of the central bearing support, in order that the pivot can be machined accordingly.

N. 24 (the number has to be defined with the manufacturer) threaded holes will have to be foreseen, both for the inner and for the outer ring . These holes have to be used for three purposes: for the fixing relevant to the Spoke device,for the clamps, and for the extraction of the AZIMUTH RADIAL BEARING.

The manufacturer will have to propose a grease lubrication system, in accordance with the requirements of this technical specification, and grant what follows:

• relubrication every minimum five years;
• low friction.

(See what indicated in the Statement of Work).

The contractor shall prepare and submit to the P.O. the Acceptance Test Plan.

The following tests and inspections shall be performed prior to Plant Acceptance, and shall be included in the Acceptance Test Plan:

• Chemical analysis of materials of bearing rings and rollers
• Materials tensile strenght
• Magnetic particle inspection and penetrant liquid inspection of the forgings
• Hardness depth (only for parts subjected to surface-hardening)
• Hardness of rollers
• Hardness of bearing races
• Roughness of bearing races
• Radial run-out of assembled bearing inner ring
• Measurement protocol of functional dimensions
• Measurement of friction torque under load (conditions to be agreed)

The supplier will have to propose a list of spare parts, granting what indicated in # 6.0

Doc_info_start
Title: AZIMUTH RADIAL BEARING
Document Type: TECHNICAL SPECIFICATION
Source: EIE
Issued by: G.MARCHIORI
Date_of_Issue: 21/09/98
Revised by:
Date_of_Revision:
Checked by:
Date_of_Check:
Accepted by:
Date_of_Acceptance:
Released by:
Date_of_Release:
File Type:MS-WORD 6
Local Name: 00397/DOC/401e046b.doc
Category: TELESCOPE AZIMUTH PLATFORM
Sub-Category: GENERAL TELESCOPE
Assembly: TELESCOPE TECHNICAL DOCUMENTS
Sub-Assembly: AZIMUTH RADIAL BEARING
Part Name:
CAN designation: 401e046
Revision: b
Doc_info_end