AU651266B2

AU651266B2 - Eccentric planetary gear for a motor vehicle seat hinge mounting

Info

Publication number: AU651266B2
Application number: AU32886/93A
Authority: AU
Inventors: Gerhard Schmale
Original assignee: Naue Johnson Controls Engineering and Co GmbH
Current assignee: Naue Johnson Controls Engineering and Co GmbH
Priority date: 1992-02-17
Filing date: 1993-02-09
Publication date: 1994-07-14
Anticipated expiration: 2013-02-09
Also published as: EP0556712A3; EP0556712A2; AU3288693A; DE4204693C2; DE4204693A1

Description

AUSTRALIA

Patents Act 651266 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: r Name of Applicant: Naue/Johnson Controls Engineering GmbH Co. KG Actual Inventor(s): Gerhard Schmale Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: ECCENTRIC PLANETARY GEAR FOR A MOTOR VEHICLE SEAT HINGE MOUNTING Our Ref 318571 POF Code: 1282/195091 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 6006 "Eccentric planetary gear for a motor vehicle seat hinge mounting" Eccentric planetary gears for motor vehicle seat hinge mountings are known from German patent specifications 16 80 128, 28 34 492 and 32 44 399 in which the journals of the toothed gearing members are narrow relative to their diameters, so that if the bearing spindle is disposed slightly crookedly to the gearing members the resulting edge pressure leads to difficulty in adjusting the angle of the backrest and in addition makes it necessary to apply a non-uniform torque. Small amounts of crookedness of the bearing spindles relative to the gearing members are unavoidable, since these members are attached independently to sheet metal pressings constituting the seat frames and ".backrests. In addition the journals lie to one side i.e.

not centrally and symmetrically of the gearing members, which introduces additional tilting moments and thereby S. increases the difficulty of operation. In the case of a 20 crash the deformations introduced also cause the bearing spindle of the gear to become even more obliquely disposed relative to the gearing members, so that the teeth come laterally partly or wholly out of engagement and as a result the breaking strength is further reduced or there is no longer any support for the position of the backrest.

Because in addition the journalling of the gearing members is not particularly free from axial play and has insufficient resistance to relatively large forces, these adverse influences are still further assisted by axial separation of the gearing members. The in-house design of the bearing arrangements of an eccentric planetary gear of this type, in accordance with German patent application P 41 17 497.6-16, which is not a prior publication, is an improvement over these known solutions and does not suffer from these main drawbacks, since the middle of the gearing members coincides axially with the abutment of the two gearing members in the bearing region on the gear spindle, and also the width of their journals is markedly increased relative to the starting material. Even here, however, a certain amount of crookedness of the spindle relative to the gearing members, or a force acting in this sense, is unavoidable owing to the inexact assembly relationships of the latter members on the sheet metal pressings forming the frames of the seat and the backrest.

In these circumstances it is a disadvantage that, as a result of their uniform all-through strength, the stiffness of the gearing members in the connection to the bearing region is very high, so that even in this case relatively high and non-uniform operating torques often have to be applied when manually adjusting the angle of the backrest by means of the eccentric planetary gear, owing to the need to overcome the forces acting. This is both perceived as annoying and increases the tendency to crookedness of the bearing spindle. Things are made worse by the fact that during the adjustment of the angle the S. occupant of the seat is often still leaning against the 20 backrest, thus increasing the operating torque that has to be applied. Particularly in the case of overload, as in a crash situation, the moments acting on the bearing spindle increase so much, as a result of the abovementioned rigid construction of the gearing members, that very high edge pressures arise in the journal. As a result a powerful axial bursting effect occurs, tending to cause the gearing members to gape apart, so that not only does the angular extent of the crookedness of the axis become large, but also, through lateral separation combined with 30 the absence of positive axial support, the engagement of the gearing members, and thus the strength of the gear, is reduced or completely lost.

The invention set forth in claim 1 is concerned with the problem of improving the behaviour of the gearing members in the connection to the bearing region in the known gears of this kind, and also in those proposed in German patent application P 41 17 497.6-16, so that the difficulties outlined above that affect the comfort of operation in adjusting the angle of the backrest are eliminated or greatly reduced, and that in the case of a crash favourable conditions of engagement are still assured, whereby even if permanent deformation cannot be avoided, the tendency to fracture is countered.

The advantages obtained with the invention are in particular that the manual adjustment of the angle of the backrest of motor vehicle seats using eccentric planetary gears is facilitated and that the torque that has to be applied is largely uniform, and that in case of a crash the gearing members are held together axially in a reliable manner. In respect of the fact that, owing to the abovementioned slight obliqueness of the bearing spindle to the gearing members, there are distortions in such gears of the previous kind that lead to difficulties, the invention provides assistance with regard to the effects of such deviations by increasing the elasticity of the rolling bodies when they are at an angle to the bearing spindle 20 without in practice decreasing the strength in respect of the torque that can be transmitted. Since in addition the tendency of the bearing bodies to gape apart axially in the journalling region is counteracted by the small amount of play and stable abutment, combined with coincidence of the middle of the tooth system with the abutment of the two rolling bodies on the bearing spindle, the engagement of the tooth systems in case of a crash is ensured, leading to increased security against fracture.

Further features of the invention are set forth in the S" 30 claims.

Exemplary embodiments of the invention are illustrated in the drawings and will now be described in more detail.

In the drawings: Fig. 1 shows a section through an embodiment of the invention, in which annular grooves are stamped in the webs of the gearing bodies and the gearing bodies are secured axially in a stable manner by a firm shoulder on the one side and the formation of a flange on the bearing spindle on the other, Fig. 2 is a detail Z from Fig. 1 that shows the outer region of the bearing arrangement before a shoulder for axial support has been produced, Fig. 3 shows an arrangement similar to that of Fig. 1, except that the axial securing is effected by pulsed current welding of an abutment bushing to the bearing spindle, Fig. 4 shows an outer part of the loose bearing spindle shown in Fig, 3, and Fig. 5 is similar to Fig. 4, except that the pulsed current weld is made on the end face of a bearing region.

In an eccentric planetary gear 1 as shown in Fig. 1 a .".pinion 2 is welded to a fitting 3 connected to one side of the frame (not shown) of a motor vehicle seat. An internal ring gear 4 meshing with the pinion 2 is similarly attached to a fitting 5 that is connected to one side of an 20 angularly adjustable backrest (not shown).

The pinion 2 and the internal gear 4 are journalled in known manner on mutually eccentrically disposed bearing regions 6 and 7 of a bearing spindle 8. The number of teeth on the pinion 2 is one less than that of the internal ring gear 4, so that self-locking occurs. Connected to a hub 9 of the pinion 2 and a hub 10 of the internal ring gear 4 are a web 11 of the pinion 2 and a web 12 of the internal gear 4, these webs being reduced in thickness on each side, by cold forming therein rounded annular grooves 30 13 and 14 respectively, to a thickness 16 of about 60% of the thickness 15 of the starting material. This results in higher elasticity of the gearing members the pinion 2 and the internal ring gear 4 in the region of the webs 11 and 12 in the neighbourhood of the bearing, whereby already in the case of manual adjustment of the angle of the backrest by turning a handwheel 17 under normal loads on the eccentric planetary gear 1 operation is made easier, insofar as the torque that has to be applied is more uniform. The explanation of this is that in such eccentric planetary gears 1, in which the journals of both the pinion 2 and of the internal ring gear 4 have a low ratio of bearing width to bearing diameter of only about one third, so that in the case of the deviations occurring in such eccentric planetary gears in the alignment of the bearing spindles 8 to the gearing members the pinion 2 and the internal ring gear 4 distortions are present that cause edge pressures in the bearings, whereby in eccentric planetary gears of this kind difficulties are to be noted arising from the need to apply high and non-uniform torques, which however are reduced through the increased elasticity of the gearing bodies 2 and 4 of the invention.

In addition the pitch circle diameters of the tooth systems amount to almost four times the bearing diameter, whereby the said difficulties are further increased.

On the inside the pinion 2 bears axially against a shoulder 18 of the bearing spindle 8.

20 The axial play of the gearing members on the spindle is made small by keeping the manufacturing tolerances correspondingly narrow, by corresponding mutual adjustment of the sum of the widths 19 and 20 of the hubs 9 and 10 and also the distance 21 between the face 22 of the shoulder 18 and the face 23 of a flanged hub part 27.

A seating part 26 of the flanged hub part 27 is fitted on an outer spigot 25 of the bearing spindle 8 and secured against rotation by a feather key 29. As can be seen from Fig. 2, the outer spigot 25 of the bearing spindle 8 is 30 made longer than the seating part 26 of the flanged hub part 27 by so much, and is provided with a recess 30 so deep, that after fitting the flanged hub part 27 on to the spigot 25 a collar 31 can be formed by upsetting or flanging of the projecting region of the spigot 25 that bears firmly against the flanged part 27 and secures it axially.

In the eccentric planetary gear 31 shown in Fig. 3 the pinion 2 and the internal ring gear 4 are journalled, likewise with only a small amount of play, likewise between the shoulder 18 of a bearing spindle 33 on the inner side and the abutment against a flanged bushing 32 on the outer side.

The flanged bushing 32 is seated on a spigot 35 of the bearing spindle 33, which is secured to the bushing by a pulsed current weld 37 to provide a connection with a high resistance to axial loading. To obtain such a high quality weld the end face 34 is provided approximately centrally, as shown in Fig. 4, with a triangular section welding ring 36.

A handwheel 11 is suitably fitted on to an outer spigot 40 of the bearing spindle 33 and secured axially by a retaining ring 41.

As shown in Fig. 5, a pulsed current weld is likewise S. provided between a bearing spindle 44 and the flanged sleeve 32 with a triangular cross-section on an end face 43, for which a welding ring 42 is provided centrally on 20 this end face 43 of the bearing spindle 44.

The invention is equally applicable to eccentric planetary gears of this kind in which, as is known from o'':German patent applications 16 80 128, 28 34 492 and 32 42 399, a spacer ring is provided between the pinion and the internal ring gear.

Claims

1. An eccentric planetary gear for hinge mountings of motor vehicle seats which serves as rotary connection, tilt adjustment and fastening, comprising a pinion and an internal ring gear made by cold extrusion moulding, wherein both the pinion and the internal ring gear have annular grooves formed in their webs adjacent to their respective hubs and wherein the hubs are fitted between shoulder-like components arranged on the axis against which they bear on either side so as to give a narrow axial play in the bearing.

2. A gear according to claim i, wherein in the connection to the bearing region on the bearing spindle the web of the pinion and the web of the internal ring gear are narrowed *o p-UAC(ec cnu(ttr grobves by cold stamping 4 symmetrically on both sides, to a residual web thickness of about 60% of the thickness of the S. starting material, the pinion bears on the inner side with 20 its hub against an end face of a shoulder of the bearing spindle, and the internal ring gear, which has its hub adjoining said pinion, likewise bears on the outer side on an end face of a hub flange part, the sum of the widths of the hubs of the pinion and the internal ring gear and the distance between the said end faces of the shoulder and of the hub flange part being mutually adapted in terms of :tolerances so that for the pinion and internal ring gear constituting the gearing members there is only a narrow axial bearing play.

3. A gear according to claim 1 or claim 2, wherein the outer end face is formed by a flanged hub part of the handwheel and the hub of said flanged part is secured axially as a result of the formation of a collar by flanging or upsetting of the end face of a spigot on which it is seated.

4. A gear according to one or more of claims 1 to 3, wherein a flange bushing having an end face for the axial abutment of the internal ring gear is secured at the end to the bearing spindle by pulsed current welding, for which purpose the end face of the bearing spindle or of a spigot thereon or an end face of a bearing region of the bearing spindle is provided with a triangular section welding ring. DATED: 8 February, 1993 PHILLIPS ORMONDE FITZPATRICK Attorneys for: c NAUE/JOHNSON CONTROLS ENGINEERING GmbH CO. KG o 0 4, 0 to I fc r Abstract "Eccentric planetary gear for a motor vehicle seat hinge mounting". Eccentric planetary gears for a motor vehicle seat hinge mounting mostly require a non-uniform and relatively high operating torque for changing the angular position of the backrest, and in case of a crash the teeth of the pinion and of the internal ring gear do not remain laterally engaged sufficiently or indeed at all, so that the holding ability is reduced or lost. To overcome this disadvantage the webs (11 and 12) of the pinion and internal ring gear are made elastically yielding in the 15 connection to their bearing region by means of annular grooves (13, 14) impressed into them on both sides, and the gearing bodies 4) are fitted axially on the bearing spindle with narrow play and secured by a shoulder (18) and a collar that form firmly seated abutments. *e *e S S