GB2054725A

GB2054725A - Vehicle lock transmission mechanism

Info

Publication number: GB2054725A
Application number: GB8016982A
Authority: GB
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1979-06-09
Filing date: 1980-05-22
Publication date: 1981-02-18
Also published as: IT8067882A0; GB2054725B; IT8053285V0; FR2458654A1; DE2923447A1; SE8003715L; JPS563772A

Abstract

A drive for a locking device on a vehicle door, more especially a motor vehicle door, the drive comprising a motor, on whose driven shaft there is coupled a gear unit which converts the rotary movement of the driven shaft of the motor into a displacing movement of a driven member of the drive which is displaceably guided in the gear case, and comprising a driver clutch, which is provided with play and is operative in both driving directions, between the driven shaft of the motor and the driven member. The driver clutch is provided in the rotary movement force path and comprises two clutch elements (31, 33) which are coaxially mounted in the gear case so as to be rotatable relative to each other. Each of the two clutch elements (31, 33) has respectively one pair of stop faces arranged at an angular distance from each other and point in opposite circumferential directions. The stop faces of one of the two clutch elements (31) have, in pairs, a smaller angular distance from each other than the pair of stop faces of the other clutch element (33) and are arranged in the rotational path between these stop faces. <IMAGE>

Description

SPECIFICATION Vehicle lock transmission mechanism The invention relates to a drive for a closing and/or locking device on a vehicle door, more especially a motor vehicle door, the drive comprising a motor, on whose driven shaft there is coupled gear unit which converts the rotary movement of the driven shaft of the motor into a displacing movement of a driven member of the drive, which member is displaceably guided in the gear case, and comprising a driver clutch, which is operative in both drive directions, between the driven shaft of the motor and the drive member.

A drive of this kind is known from German Offenlegungsschrift 25 57 970. On this drive, an electric motor drives a flywheel which is coupled with the gearing so as to be secured against rotation and serves as an accumulator. As the driven member there serves a rod which is displaceably guided in a rack which can be displaced by the gearing. On both sides of the rack front ends which are located in the direction of displacement the rod is provided with stops which form, with these front ends, a driver clutch. The distance between the stops is larger than the distance between the faces to that an idle path comes about in both directions of movement before the rack strikes against the stops of the rod serving as the driven member. The idle path is so dimensioned that the electric motor, including the flywheel and the gearing, can start up until the idle path has been compensated for.One of the stops is spring-loaded through a helical spring so as to allow the locking device also to be actuated by hand, if necessary, through an actuating button coupled with the rod.

However, the known drive is relative voluminous since, in addition to the displacement path of the rack, the displacement path of the rod serving as the driven member has for sealing reasons to be disposed in the gear case. The helical spring, which also extends in the direction of displacement of the rack, necessitates additional space.

The known drive is so designed with respect to the flywheel effect of its flywheel that very high forces are exerted on the rack for a short time so as to allow the closing or locking device to be reliably engaged. However, if no high forces are required during the closing movement, as is the case, for example, in connection with a lock of easy motion, then the high forces become active on the stops which bound the lock stroke, which may result in the destruction of the lock or, more especially, the gearing of the drive.

It is the object of the invention to show a method of reducing the space requirement of a drive of the kind illustrated at the beginning, on the one hand, and avoiding damage to the parts provided for limiting the lock stroke, on the other hand, at a relative low constructional expenditure.

According to the invention, this problem is solved in that the driver clutch is provided in the rotary movement force path and comprises two clutch elements which are coaxially mounted in the gear case so as to be rotatable relative to each other, and in that each of the two clutch elements comprises at least one pair of stop faces which are arranged at an angular distance from each other and point in opposite circumferential directions, and in that the stop faces of one of the two clutch elements are in pairs at a shorter angular distance from each other than the pair of stop faces of the other clutch element and are arranged in the rotary path between these stop faces.

On this drive, the space in the gear case that is necessary anyway for the gears of the gear unit is utilised for accommodating the driver clutch. No additional space has to be provided for the idle path of the driver clutch. On the known drive, the driver clutch, which is subjected to play, is arranged downstream of the gear unit so as to make possible a maximum starting rotation angle for the flywheel. However, tests made in practice have shown that the starting angle which the parts producing the flywheel effect require in order to produce a sufficiently high torque is substantially smaller than was originally assumed.

The driver clutch can therefore be inserted in the rotary movement force path of the gear unit.

Particularly small constructional forms are achieved if one of the two clutch elements is coaxially arranged in an axial recess in the other clutch element, particularly so if the external clutch element is toothed on its circumferential surface and the internal clutch element is connected to a coaxial pinion so as to be secured against rotation. In this way, the driver clutch can be readily integrated in a gear of the gear unit which has to be provided anyway. A driver clutch which is stable and can stand up to permanent operation is obtained if a cam projects radially inwardly from the inner surface of the external clutch element and if the internal clutch element is a segmental disc, whose radial faces strike against the cam.

Of considerable importance are constructional forms wherein the stop faces of one of the two clutch elements are provided on at least one deformable part which transmits the torque. This deformable part forms an energy-absorbing damping device which is inserted in the force path between the driven shaft of the motor and the driven member and which is operative between the two clutch elements which can be rotated relative to each other. This damping device therefore does not require any or hardly any additional space, even if the clutch elements are cushioned against shocks in both directions of rotation, as is preferably provided for.

In a preferred constructional form, the deformable part is designed as a radially elastically deformable sleeve, whose circumferential surface forms the stop face. The sleeve is expediently held on the clutch element in that it is inserted, so as to be axially parallel to the axis of rotation of the clutch elements, in a recess in one clutch half, which recess encloses it over a circumferential angle of more than 180 . The associated stop face of the other clutch element is formed by the face of a ring segment that is coaxial with the axis of rotation, which face plunges into the recess and points in the circumferential direction. The sleeve preferably consists of a rubber-elastic material.

Instead of the sleeve, there may however be provided a buffer block or the like means which is suitably shaped in a different manner and can be deformed in a rubber-elastic manner upon the exertion of pressure.

In another preferred constructional form, one clutch element has a circular hollow cylinder which is coaxial with its axis of rotation and in which there is placed a spring part which is resilient radially to the axis of rotation and bears against the inner surface of the hollow cylinder over a circumferential angle of less than 3600 and whose ends project radially inwardly for the formation of the stop faces. The spring part forms, together with a hollow cylinder, a friction safety clutch which can only transmit a preset maximum torque. In its simplest constructional form, the spring part is a spring band whose ends are bent radially inwards.

In another preferred constructional form, the stop faces of both clutch elements extend obliquely to the radial planes extending through the axis of rotation of the clutch elements. The deformable part, on which the stops of one clutch element are provided, has to be elastic radially to the axis of rotation. When the oblique stop faces meet, the stop faces held on the deformable part are radially deflected, thus causing the shock energy to be absorbed. The stop faces, which are oppositely directed in pairs, preferably form radially inwardly or outwardly pointing cams.

Upon shock loading, the cams held on the deformable part snap over the cams of the other clutch element. The deformable part is preferably formed by a spring arm which freely projects from a boss of one clutch element substantially in the circumferential direction and is elastic to bending.

This spring arm is accommodated in the space, which is provided anyway, between the boss and the cams of the other clutch element which preferably project inwardly on the inner surface of a hollow cylinder. The space suffices in order to accommodate, if necessary, two spring arms which project in opposite directions and have diametrically opposite cams. Diametrically opposite cams may be provided in pairs on the other clutch element. The flywheel energy from the rotating parts does not have to be consumed on a single cam; on the contrary, several cams can successively become operative.

Preferred exemplified embodiments of the invention will be explained in more detail hereinafter with reference to drawings, in which: FIGURE 1 shows a partly sectional side view of a drive for a locking device of a motor vehicle door; FIGURE 2 shows an axial longitudinal section for a first constructional form of a driver clutch usable in the drive shown in Fig. 1; FIGURE 3 shows a cross section along the line Ill-Ill through the driver clutch shown in Fig. 2; FIGURE 4 shows an axial longitudinal section through a second constructional form of a driver clutch usable in the drive shown in Fig. 1; FIGURE 5 shows a cross section along the line V-V through the driver clutch shown in Fig. 4;; FIGURE 6 shows an axial longitudinal section through a third constructional form of a driver clutch usable in the drive shown in Fig. 1; FIGURE 7 shows a cross section along the line VIl-VIl through the driver clutch shown in Fig. 6; FIGURE 8 shows an axial longitudinal section through a fourth constructional form of a driver clutch usable in the drive shown in Fig. 1, and FIGURE 9 shows a cross section along the line IX-IX through the driver clutch shown in Fig. 8.

Fig. 1 shows an electric drive for the locking device on a motor vehicle door, which drive comprises an electric motor 1 which is coupled through a gear unit 3 to a push rod 5. The push rod 5 is provided at its free end with an eye hook 7, in which there is placed a push wire 8 which, with its other end, actuates a locking device (not shown) of a motor vehicle door lock. The electric motor 1 and the push rod 5 are held or displaceably guided on a housing 9 of the gear unit 3. The gear unit 3 converts the rotary movement of a driven shaft of the electric motor 1 , which shaft is designated 11, into the displacing movement of the push rod 5.On the driven shaft 1, there is mounted a pinion 13 which meshes with a gear 1 5. Through a driver clutch 17, which will be described in detail hereinafter and which is provided with play, the gear 1 5 is coupled with a pinion 1 9 which is coaxially mounted on a common shaft 1 8 and meshes with a rack 21 which is connected to the push rod 5. A pin 25, which engages in a recess 23 in the push rod 5 and is fixed on the housing, limits the displacement path of the push rod 5 in accordance with the end walls 27 of the recess 23 which are located in the direction of displacement.

The electric motor 1 is a direct-current permanent-magnet motor whose direction of rotation is reversible and whose rotor flywheel mass is utilised as an energy store for the actuation of the locking device. The idle play of the drive clutch allows the electric motor 1 to be started up without moving the push rod 5. Only when the play of the driver clutch 1 7 has been compensated for is the push rod 5 moved.

Figs. 2 and 3 show a first constructional form of a driver clutch. The driver clutch comprises two clutch elements 31,33 which can be rotated about a common axis and of which the clutch element 31 is provided on its outer circumference with teeth 35 for engagement in the pinion 1 3 of the electric motor 1 and the clutch element 33 is coupled in a positive non-rotatable manner with a coaxially arranged pinion 37 which is destined for engagement in the rack 21. The clutch element 33 sits in a recess 39 in the clutch element 31, which recess engages axially in the clutch element 31 which is mounted on a bearing lug 41, which projects from the clutch element 33, on the side of the clutch element 33 that is directed away from the pinion 37. The recess 39 is of substantially circular-cylindrical shape.From its inner surface there projects a cam 43 radially to the inside. The cam 43 has two radially extending stop faces 45, 47 which point into opposite circumferential directions. The clutch element 33 has the shape of a circular-segment disc with two radially extending stop faces 49, 51 which point towards each other. The cam 43 engages between the stop faces 49, 51. The angular distance between the stop faces 49, 51 is larger by an angle (x than the angular distance between the stop faces 45, 47. The clutch element 31 can therefore be rotated relative to the clutch element 33 through the angle rr between its two torque-transmitting end positions.This idle path is so dimensioned that during the compensation of the idle path the electric motor 1 can accelerate, on account of the flywheel effect of its armature, to a rotational speed which is sufficient for the actuation of the locking device.

Figs. 4 and 5 show a second constructional form of a driver clutch. This clutch again consists of two clutch elements 61, 63 which are coaxially arranged one within-the other and of which the clutch element 61 is provided with teeth 65, which are destined for engagement in the pinion 13 of the motor 1, on its circumference engaging over the clutch element 63. The clutch element 63 is coupled in a positive non-rotatable manner with a pinion 67 which is destined for engagement in the rack 21. The clutch element 63 sits in a hollow-cylindrical recess 69 in the clutch element 61. A spring band 70, which extends over less than 3600 of the inner circumference of the recess 69, is inserted in the recess 69. The ends of the radially outwardly resilient spring band 70 are angled radially to the inside and form two stop faces 72, 75 which point in opposite circumferential directions.Instead of the spring band, it is possible to provide a spring part made of spring wire. The clutch element 63 has the shape of a cylinder segment and comprises two stop faces 77, 79 which are directed towards each other in the circumferential direction and extend substantially radially. The angular distance between the stop faces 72, 75 is smaller than the angular distance between the stop faces 77, 79.

The stop faces 72, 75 engage between the stop faces 77, 79 with a play extending over the angle (r. The play is dimensioned to be so large that until the compensation for the play the electric motor 1 is brought to the rotational speed which is suitable for the actuation of the locking device on account of the flywheel effect of its rotor. The spring band 70 forms, together with the inner surface of the recess 69, a friction clutch which can indeed transmit the torque applied by the motor but not the motor rotor flywheel effect which arises upon the impingement of the push rod or another part of the locking device.

Figs. 6 and 7 shows a third constructional form of a driver clutch with two clutch elements 71, 73 which are coaxially arranged so as to be rotatable one within the other and of which the clutch element 71 is provided on its cylindrical circumference with teeth 78, which are destined for engagement with the pinion of the electric motor, and the clutch element 73 is coupled, in accordance with the constructional forms explained above, with a coaxial pinion 80 which is destined for engagement with the rack 21. The clutch element 73 sits in a hollow-cylindrical recess 81 in the clutch element 71, which recess has on its cylindrical inner surface four cams 83 which are staggered by 900, that is to say which are diametrically opposite to one another in pairs, and whose flanks 85, 87 point away from each other and are inclined towards the radial direction.

Instead of four cams 83, it is possible to provide a larger even number of cams, e.g. six or eight pieces. The clutch element 73 comprises a boss 89 which is coupled with the pinion 80 and from which a web 91 projects radially. The web 91 is provided with two spring arms 93, 95 which freely project towards opposite sides approximately in the circumferential direction and which have at their free ends, diametrically opposite to each other, two outwardly projecting cams 97, 99. The cam faces of the cams 97 and 99 extend obliquely towards each other to the outside and engage in the movement path of the cams 83. The cams 97 and 99 resin pairs against opposite cams 83 of the clutch element 71.The radial spring force in the spring arms 93, 95 is so dimensioned that the driver clutch can transmit the electrically produced torque of the electric motor but not the additional flywheel effect arising when a stop is hit. In this case, the cams 97, 99 snap above the cams 83 while the spring arms 93, 95 are deflected. The angular distance between the two cam faces of each of the two cams 97, 99 is smaller than the angular distance between the facing cam faces of adjacent cams 83. In this way, there is provided an idle play whose angle rU is so dimensioned that until the compensation for the idle play the electric motor 1 can reach a rotational speed that is adequate for the required flywheel effect.

Figs. 8 and 9 show a fourth constructional form of a driver clutch. This driver clutch comprises two clutch elements 101,103 which can be rotated relative to each other about a common axis and of which the clutch element 101 is provided on its outer circumference with teeth 105 for engagement in the pinion 13 of the electric motor 1 and the clutch element 103 is coupled in a positively non-rotatable manner with a pinion 107 which is coaxially arranged and is destined for engagement in-the rack 21. The clutch element 103 sits in a clutch element 101 recess 109 which engages axially in the clutch element 101 which is mounted on a bearing lug 111, which projects from the clutch element 103, on the side of the clutch element 103 that is directed away from the pinion 107.

On the inner surface of the recess 109, there are provided two recesses 113,115 which open in two opposite circumferential directions. The recesses are of substantially circular cylindrical shape and enclose over an angle of more than 1 800 sleeves 11 7 and 11 9 respectively which are arranged so as to be coaxial with the axis of rotation of the clutch elements 101, 103 and are made of a rubber-elastic material.The sleeves 11 7, 11 9 are accessible in the circumferential directional from the open side of the recesses 113,115 and form stop faces for the faces 121, 123, which are directed towards each other in the circumferential direction, of a ring segment 125 which concentrically encloses the axis of rotation of the clutch elements 101, 103 and which is held on a boss 1 27 which is coupled with the pinion 107. The angular distance between the faces 121, 123 is larger than the angular distance between the two zones of the sleeves 11 7, 11 9 which form the stop faces. The clutch element 101 can therefore be rotated through an angle cr relative to the clutch element 103 before it transmits a torque to this element. The idle path is so dimensioned that, during the compensation for the idle path, the electric motor 1 can accelerate to a rotational speed that is sufficient for the actuation of the locking device on account of the flywheel effect of its armature. The eleastic sleeves 11 7, 11 9 form energy-absorbing damping elements which elastically intercept the rotor of the electric motor when one of the elements of the gear unit or of the locking device, for example the pin 25, impinges on a stop. A cover plate 129 of the clutch element 103 closes the recess 109 in a clutch element 101 in a protective manner. Such a cover plate may also be provided in the other constructional forms.

Claims

1. A drive for a closing and/or locking device on a vehicle door, more especially a motor vehicle door, the drive comprising a motor, on whose driven shaft there is coupled a gear unit which converts the rotary movement of the driven shaft of the motor into a displacing movement of a driven member of the drive which is displaceably guided in the gear case, and comprising a driver clutch, which is provided with play and is operative in both driving directions, between the driven shaft of the motor and the driven member, characterised in that the driver clutch is provided in the rotary movement force path and comprises two clutch elements which are coaxially mounted in the gear case so as to be rotatable relative to each other, and in that each of the two clutch elements has respectively one pair of stop faces which are arranged at an angular distance from each other and point in opposite circumferential directions, and in that the stop faces of one of the clutch elements have, in pairs, a smaller angular distance from each other than the pairs of stop faces of the other element and are arranged in the rotational path between these stop faces.

2. A drive as claimed in Claim 1, characterised in that one of the two clutch elements is coaxially arranged in an axial recess in the other clutch element.

3. A drive as claimed in Claim 2, characterised in that the external clutch element is toothed on its circumferential surface and the internal clutch element is connected to a coaxial pinion so as to be secured against rotation.

4. A drive as claimed in Claim 2, characterised in that a cam projects radially inwardly from the inner surface of the external clutch element and in that the internal clutch element is a segmental disc, whose radial surfaces strike against the cam.

5. A drive as claimed in Claim 1, characterised in that the stop faces of one of the two clutch elements are provided on at least one deformable part which transmits the torque.

6. A drive as claimed in Claim 5, characterised in that the deformable part is designed as a radially elastically deformable sleeve whose circumferential surface forms the stop face.

7. A drive as claimed in Claim 6, characterised in that the sleeve is inserted, in an axially parallel manner to the axis of rotation of the clutch elements in a recess in one clutch element, which recess encloses the sleeve over a circumferential angle of more than 1800, and in that the associated stop face of the other clutch element is formed by the face of a ring segment which is coaxial with the axis of rotation, which face plunges in the recess and points in the circumferential direction.

8. A drive as claimed in Claim 5, characterised in that the deformable part consists of a material which is deformable in a rubber-elastic manner upon the exertion of pressure.

9. A drive as claimed in Claim 5, characterised in that one clutch element comprises a circular hollow cylinder which is coaxial with its axis of rotation and in which there is inserted a spring part which is resilient radially to the axis of rotation and which bears against the inside surface of the hollow cylinder over a circumferential angle of less than 3600 and whose ends project radially inwardly for the formation of the stop faces.

10. A drive as claimed in Claim 9, characterised in that the spring part is designed as a spring band, whose ends are bent radially inwardly.

11. A drive as claimed in Claim 5, characterised in that the stop faces of both clutch elements extend obliquely to the radial planes which extend through the axis of rotation of the clutch elements and in that the deformable part is elastic radially to the axis of rotation.

12. A drive as claimed in Claim 11, characterised in that the stop faces which are oppositely directed in pairs form radially inwardly or outwardly pointing cams.

1 3. A drive as claimed in Claim 12, characterised in that the deformable part is formed by a spring arm which freely projects from a boss of one clutch element substantially in the circumferential direction and which is elastic to bending.

14. A drive as claimed in Claim 13, characterised in that one clutch element comprises two spring arms which project in opposite directions and have diametrically opposite cams which point radially to the outside and in that the other clutch element comprises cams which are diametrically opposite to each other in pairs and point to the inside.

1 5. A drive for a closing and/or locking device on a vehicle door, more especially a motor vehicle door substantially as described with reference to the accompanying drawings.