Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUSRE33868 E
Publication typeGrant
Application numberUS 07/488,236
Publication dateApr 7, 1992
Filing dateMar 2, 1990
Priority dateAug 27, 1985
Fee statusPaid
Also published asCA1274699A1, DE3530600A1, EP0213529A1, EP0213529B1, US4750250
Publication number07488236, 488236, US RE33868 E, US RE33868E, US-E-RE33868, USRE33868 E, USRE33868E
InventorsWolfgang Maus, Helmut Swars
Original AssigneeMannesmann Fahrzeugtechnik GmbH
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of fastening drive elements of a hollow shaft
US RE33868 E
Abstract
Method fastening drive elements on a hollow shaft, which comprises:
pushing n drive elements with a thickness a over a hollow shaft, retaining the drive elements at mutual spacings b and in respective desired azimuthal positions by means of holding devices;
providing active sections of a material with a given limit of elasticity, a length c, mutual spacings d and being bounded by sealing lips on a hydraulic expanding device so that .[.n (a+b)=n (c+d).]. .Iadd.n.a+(n-1) b=n.c+(n-1) d.Iaddend., pushing the hydraulic expanding device into the hollow shaft; and
applying a pressure through the hollow shaft to the active sections stressing the material of the active sections radially beyond the given limit of elasticity.
Images(1)
Previous page
Next page
Claims(2)
We claim:
1. Method of fastening drive elements on a hollow shaft, which comprises:
pushing .[.n.]. drive elements with a thickness .[.a.]. over a hollow shaft of a material with a given limit of elasticity, retaining the drive elements at mutual spacings .[.b.]. and in respective desired azimuthal positions by means of holding devices; providing .Iadd.a hydraulic expanding device having .Iaddend.active sections with a length .[.c.]., mutual spacings .[.d.]. and .[.being bounded by.]. sealing lips .[.on a hydraulic expanding device so that n(a+b)=n(c+d).]. .Iadd.bounding the active sections.Iaddend., pushing the hydraulic expanding device into the hollow shaft;
applying a pressure through the hydraulic expanding device to the active sections stressing the material of portions of the hollow shaft opposite the active sections radially beyond the given limit of elasticity and into secured engagement with the drive elements;
reducing the pressure at the active sections; and withdrawing the hydraulic expanding device from the expanded hollow shaft.
2. Method according to claim .[.1.]. .Iadd.4.Iaddend., which comprises making a=c. .[.3. Method according to claim 1, which comprises making b=d.].. .Iadd.4. Method according to claim 1, which comprises making n.a+(n-1)b=n.c+(n-1)d, wherein n is the number of drive elements, a is the thickness of the drive elements, b is the spacing between the drive elements, c is the length of the active sections, and d is the spacing between the active sections.Iaddend..
Description

The invention relates to a method of fastening drive elements on a hollow shaft.

The method is described below by using an example of a cam shaft for four-cycle internal combustion engines, but it is similarly applicable to other drive elements, such gears, bearing shells and the like which are to be fastened to a smooth shaft, so as to be secure against rotation and axial shifting. Although numerous fastening possibilities are known from German Published, Non-Prosecuted Application No. DE-OS 23 36 241, they appear to be too costly to be used for mass production.

It is accordingly an object of the invention to provide a method of fastening drive elements on a hollow shaft, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, and which permits a maximum number of drive elements to be simultaneously fastened on a shaft with a minimum number of operations. Instead of expensive turned parts, less expensively producible precision tubing is to be used for the shafts, and machining and heat treating operations which may be required on the drive elements themselves should be performed prior to the actual assembly.

With the foregoing and other objects in view there is provided, in accordance with the invention, a method of fastening drive elements on a hollow shaft, which comprises:

pushing n drive elements with a thickness a over a hollow shaft, retaining the drive elements at mutual spacings b and in respective desired azimuthal positions to be assumed by means of holding devices; providing active sections of a material with a given limit of elasticity, a length c, mutual spacings d and being bounded by sealing lips on a hydraulic expanding device so that .[.n(a+b)=n(c+d).]. .Iadd.n.a+(n-1)b=n.c+(n-1)d.Iaddend., pushing the hydraulic expanding device into the hollow shaft; and applying a pressure through the hollow shaft to the active sections stressing the material of the active sections radially beyond the given limit of elasticity.

Hydraulic expanding devices of this type are known in principle, although each has only one active section, e.g. for the fastening of heat exchanger tubes in tube plates. The method according to the invention is also well adapted to the pairing of materials such as a relatively tough, readily deformable shaft material with the higher grade, normally hardened material of the drive elements, which is desirable for other reasons as well. It is not difficult to adapt the hydraulic expanding device to the number of drive elements to be fastened on the shaft in one operation and to adapt it to their possibly uneven mutual spacings.

In accordance with a concomitant mode of the invention, there is provided a method which comprises making a=c or b=d. This method is used because it appears advantageous to utilize the entire contact area between the drive elements and the associated shaft sections to produce the positive frictional connection.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a method of fastening drive elements on a hollow shaft, it is nevertheless not intended to be limited to the details shown, since various modifications may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary, diagrammatic, axial, longitudinal sectional view taken along the line I--I in FIG. 2, in the direction of the arrows; and

FIG. 2 is an elevational view as seen along the arrow II in FIG. 1.

Referring now to FIGS. 1 and 2 of the drawings in detail, there is seen a cam shaft for a four-cylinder internal combustion engine such as is used in motor vehicles, having cylinders Z 1 to Z 4 with cams 1 which control intake valves and other cams Z which control outlet valves. The cams are retained by an appropriate number of holding tools or devices 3 which may be tong or clamp-shaped. The holding devices are in respectively required azimuthal alignment, are accurately spaced axially and are coaxial. The cams or drive elements 1 and 2 are finished, i.e. ground and hardened. The cams or drive elements have a uniform thickness, but need not necessarily have the illustrated uniformity and are disposed at distances b1, b2, b3 from each other, which may vary if desired. A hollow shaft 4 formed of a relatively tough steel is pushed through bores formed in the cams 1, 2 with a sightly larger diameter than the shaft. A hydraulic expanding device 5 is pushed into the hollow shaft 4 when the shaft is pushed through the bores or in a second operation. In addition to conventional non-illustrated pressure generating devices, the expanding device 5 is formed of a tube 6 on which active sections are installed at varying distances (d1, d2, d3 corresponding to the mutual spacings of the cams or drive elements. The active sections have a width c which may be narrower than a width a of the cams as shown but preferably is the same. In the latter case, the distances b1, b2, b3 between the cams are naturally equal to the distances d1, d2, d3. The active sections are formed by elastic rings or sealing lips 7 which are inserted in pairs into grooves formed in the surface of the tube 6. At least one hole 8 is provided in the tube 6 between each two rings of a pair through which hydraulic fluid can escape into the space between the elements 7. The elements 7 are constructed in such a way that they are slightly smaller than the inside diameter of the tube 4 in their relaxed state while contacting the inner wall surface of the tube 4 when pressure is applied, preventing the escape of the hydraulic fluid from the active sections to a large extent. The hydraulic fluid pressure is sufficient to expand the tube 4 in the vicinity of the active sections by exceeding the elasticity limit. After the conclusion of this process in all of the active sections, the device 5 is simultaneously made pressureless again for all drive elements and is pulled out of the tube 4. The holding devices 3 can then be opened and the cam shaft can be transported to the location of the next operation.

FIG. 2 shows the sectors associated with the individual cylinders Z 1 AND Z 4 in which the valves associated with the cylinders must be controlled and which accordingly determine the cam orientation.

The foregoing is a description corresponding in substance to German Application No. P 35 30 600.9, filed Aug. 27, 1985, the International priority of which is being claimed for the instant application, and which is hereby made part of this application. Any material discrepancies between the foregoing specification and the afore-mentioned corresponding German application are to be resolved in favor of the latter.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2892254 *Jun 8, 1953Jun 30, 1959American Radiator & StandardMethod of making cam shafts
US3131467 *Oct 11, 1960May 5, 1964Olin MathiesonMethod of explosively bulging a tube by a tape wound about an explosive charge
US3977068 *Jul 14, 1975Aug 31, 1976Balcke-Durr AktiengesellschaftDevice and method for expansion-swaging tubes into the bores of a tube plate
US4210991 *Sep 5, 1978Jul 8, 1980Westinghouse Electric Corp.Hydraulic expansion swaging of tubes in tubesheet
US4368571 *Sep 9, 1980Jan 18, 1983Westinghouse Electric Corp.Sleeving method
US4420867 *Feb 16, 1982Dec 20, 1983Wilfried BusseMethod of pressure fitting a tube in a tube sheet
US4445261 *Jul 28, 1980May 1, 1984Haskel, IncorporatedMethod for installing tubes in a tube sheet
US4597365 *Feb 7, 1985Jul 1, 1986General Motors CorporationCamshaft assembly and method
US4608739 *Mar 21, 1984Sep 2, 1986Big-Inch Marine Systems, Inc.Connector of and sealing of tubular members
US4622732 *Nov 23, 1984Nov 18, 1986Haskel, Inc.Method for forming joints in pressurized fluid systems
US4660269 *May 12, 1986Apr 28, 1987Musashi Seimitsu Kogyo Kabushiki KaishaProcess for producing built-up camshafts
US4727635 *Apr 24, 1987Mar 1, 1988Balcke-Durr AktiengesellschaftMethod of securing tubes between tube sheets
US4781076 *Jan 17, 1986Nov 1, 1988The Torrington CompanyCamshaft for reciprocating piston engines
DE2232438A1 *Jul 1, 1972Jan 10, 1974Kloeckner Humboldt Deutz AgNockenwelle, insbesondere fuer hubkolbenbrennkraftmaschinen
DE2336241A1 *Jul 17, 1973Feb 6, 1975Volkswagenwerk AgCompound camshaft assembly for combustion engine - consists of shaft carrying separate bearings cams gearwheels etc fixed in correct positions
DE2914095A1 *Apr 7, 1979Oct 16, 1980Daimler Benz AgHollow camshaft for IC engine prodn. - involves deep drawn half cams or bearings assembled mirror symmetrically and welded, with flanges formed by forging, or casting etc.
DE2922509A1 *May 31, 1979Dec 4, 1980Mannesmann AgVerfahren und vorrichtung zur herstellung von nockenwellen
FR2531883A1 * Title not available
GB1117816A * Title not available
SU1232338A1 * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5220727 *Jun 25, 1992Jun 22, 1993Hochstein Peter AMethod making cam shafts
US7210219Aug 30, 2002May 1, 2007Cinetic Automation CorporationCir-clip to shaft insertion tool
Classifications
U.S. Classification29/888.1, 72/58, 29/523, 74/567
International ClassificationB23P11/02, F01L1/047, B21D39/20, B21D53/84, B21D39/04, F16H53/02
Cooperative ClassificationB21D53/845, Y10T74/2101, B21D39/04, Y10T29/49805, F16H53/025, F01L1/047, B21D39/203, Y10T29/4994, Y10T29/49293, B23P2700/02
European ClassificationF01L1/047, B21D39/20B, B21D53/84A, B21D39/04
Legal Events
DateCodeEventDescription
Oct 28, 1991ASAssignment
Owner name: MANNESMANN FAHRZEUGTECHNIK GMBH A GERMAN CORPORAT
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:EMITEC GESELLSCHAFT FUR EMISSIONSTECHNOLOGIE MBH;REEL/FRAME:005887/0833
Effective date: 19911014
Nov 14, 1995FPAYFee payment
Year of fee payment: 8
Nov 22, 1999FPAYFee payment
Year of fee payment: 12