GB1565621A – Drive pinion assembly for a starter
– Google Patents
GB1565621A – Drive pinion assembly for a starter
– Google Patents
Drive pinion assembly for a starter
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Publication number
GB1565621A
GB1565621A
GB1657/78A
GB165778A
GB1565621A
GB 1565621 A
GB1565621 A
GB 1565621A
GB 1657/78 A
GB1657/78 A
GB 1657/78A
GB 165778 A
GB165778 A
GB 165778A
GB 1565621 A
GB1565621 A
GB 1565621A
Authority
GB
United Kingdom
Prior art keywords
drive member
drive pinion
freewheel
drive
cage
Prior art date
1977-01-17
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB1657/78A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Societe de Paris et du Rhone SA
Original Assignee
Societe de Paris et du Rhone SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1977-01-17
Filing date
1978-01-16
Publication date
1980-04-23
1978-01-16
Application filed by Societe de Paris et du Rhone SA
filed
Critical
Societe de Paris et du Rhone SA
1980-04-23
Publication of GB1565621A
publication
Critical
patent/GB1565621A/en
Status
Expired
legal-status
Critical
Current
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Classifications
F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
F16D41/00—Freewheels or freewheel clutches
F16D41/06—Freewheels or freewheel clutches with intermediate wedging coupling members between an inner and an outer surface
F16D41/064—Freewheels or freewheel clutches with intermediate wedging coupling members between an inner and an outer surface the intermediate members wedging by rolling and having a circular cross-section, e.g. balls
F16D41/066—Freewheels or freewheel clutches with intermediate wedging coupling members between an inner and an outer surface the intermediate members wedging by rolling and having a circular cross-section, e.g. balls all members having the same size and only one of the two surfaces being cylindrical
F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
F02N15/00—Other power-operated starting apparatus; Component parts, details, or accessories, not provided for in, or of interest apart from groups F02N5/00 – F02N13/00
F02N15/02—Gearing between starting-engines and started engines; Engagement or disengagement thereof
F02N15/022—Gearing between starting-engines and started engines; Engagement or disengagement thereof the starter comprising an intermediate clutch
F02N15/023—Gearing between starting-engines and started engines; Engagement or disengagement thereof the starter comprising an intermediate clutch of the overrunning type
Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
Y10T74/00—Machine element or mechanism
Y10T74/13—Machine starters
Description
PATENT SPECIFICATION
( 21) Application No 1657/78 ( 22) Filed 16 Jan 1978 ( 31) Convention Application No 7701827 ( 32) Filed 17 Jan 1977 in ( 33) France (FR) ( 44) Complete Specification published 23 April 1980 ( 51) INT CL 3 F 02 N 15/06 ( 52) Index at acceptance FIK 4 A 3 4 A 4 4 C 1 ( 54) DRIVE PINION ASSEMBLY FOR A STARTER ( 71) We, SOCIETE DE PARIS ET DU RHONE, a French Societe Anonyme, of 36 Avenue Jean Mermoz, 69008 Lyon, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in
and by the following statement:-
The present invention relates to improvements made to a drive pinion assembly of an electric starter, that is to say the axially displaceable part which permits the driving of the large crown wheel of an internal combustion engine by means of the electric starter motor.
The part in question comprises a member (herein referred to as the drive member”), the bore of which is provided with splines cooperating with other splines provided on the periphery of the motor shaft, and a pinion intended for driving the large crown wheel The drive pinion assembly includes a freewheel of which the outer cage is traditionally on the drive member, whilst the inner track is solid with the aforesaid pinion.
A certain number of difficulties are encountered in connection with the freewheel, which is generally of the wedgable roller type.
In order to improve the operation and utilisation of a pinion assembly of this kind, the expedient has been adopted of inverting the freewheel so that its outer cage is solid with the pinion, whilst the inner track forms an integral part of the drive member A drive pinion assembly of this kind is described in British Patent No 994,887.
Despite the advantages that can be expected on an arrangement of this kind, it does not permit correct operation.
On the one hand the cage is overhung in relation to its part which constitutes a bearing, so that at high speeds the axis of rotation of this cage may be longer be coincident with that of the shaft.
Furthermore, the cage and the drive member between which the wedgable rollers are mounted are not centred directly in relation to one another, but are centred relative to a third part, namely the motor shaft Thus, each of the two elements behaves independently of the other, so that any uneven running due to manufacturing tolerances becomes accentuated.
These defects entail premature mear on the rollers, so that the life of the drive pinion assembly is decidedly inadequate having regard to the requirements of users.
The improvements which form the subject of the present invention enable the disadvantages mentioned above to be reduced or obviated.
To this end, we extend the bearing surface round the shaft of the part of the freewheel assembly which includes the cage and the drive pinion by a sleeve which extends into a bore in the drive member under the said track.
According to the present invention, therefore, we provide a drive pinion assembly for an electric starter for an internal combustion engine having a drive member splined on the starter motor shaft and a freewheel assembly including an inner track formed on the drive member and an outer cage round the said track, which cage is solid with the drive pinion and is mounted for free rotation on the starter motor shaft, wherein the bearing surface of the said drive pinion round the said shaft is extended axially by a sleeve which extends into a bore in the drive member under the said track.
Whilst it would clearly be possible to provide the drive member with a sleeve bearing between the outer surface of the sleeve and the inner surface of the bore, we find it is usually sufficient to make the two parts to fit one within the other with sufficient clearance to allow relative rotation of the two parts without permitting them a relative radial motion such as would impair the proper functioning of the freewheel.
One form of the invention given by way of example, will now be described with reference to the accompanying drawings, wherein:
( 1) 1 565 621 1,565,621 Figures 1 to 3 are diagrams explaining the operation of conventional drive pinion assemblies of electric starters; Figure 4 is a partial longitudinal section of a drive pinion assembly constructed in accordance with the invention; and Figure 5 is a section thereof on the line V-V in Figure 4.
It should first be noted that there exists a cut-out speed of the freewheel to which a determined angular velocity W corresponds.
For this speed each roller G is subjected to a centrifugal force F=Mw 2/R, resulting in forces exerted bv the roller, of which a component f is directed parallel to the line of action of the spring (Figure 1), M represents the mass of each roller and R its distance from the centre of the freewheel.
This direction of the force f is very substantially tangential to the circle of radius r passing through the centre of the spring, and the direct centrifugal effects of this force on the spring can in fact be ignored.
In the position of equilibrium we can write P=f, P being the load on the spring.
The no-load speed of the armature is about 12,000 r p m, but it is not constant and depends on the voltage at the terminals of the motor, that is to say in fact on the state of charge of the battery supplying the motor.
With regard to the relative values of the no-load speed V of the armature and the cutout speed VD, two cases may arise when the cage is rigid with the drive member:
I) V O
It is seen that the armature accelerates from V to V, because the pinion is driven by the engine turning at a determined speed V,, (generally>V 0) When the armature reaches the speed V, at which the freewheel cuts out, the connection between the drive member and the pinion is broken, and the armature therefore tends to decelerate and return to its no-load speed V, while however the freewheel re-engages at a speed VR,
