GB2068077A

GB2068077A - Flexible-rack and pinion-gear drive mechanism

Info

Publication number: GB2068077A
Application number: GB8041478A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1979-12-31
Filing date: 1980-12-30
Publication date: 1981-08-05
Also published as: FR2473138B1; JPS5697656A; DE3047800C2; GB2068077B; FR2473138A1; DE3047800A1

Abstract

A flexible-rack and pinion-gear drive mechanism for use in, for example, a window regular system for a vehicle door structure, comprises a pinion gear (34) to be driven for rotation by, for example, a window manipulating handle (24), and an elongated flexible rack member (41) constituted by a helically coiled elastic wire (42) or a helically grooved elastic member, wherein the coiled elastic member (42) or the grooved elastic member has, when at least partially curved, helix elements (H, H') which are spaced from one another along the outer ridge of the expanded side of the curved portion of the rack member (41) and form therebetween clearances (G) through which the pinion gear (34), which is preferably constituted by a spur gear, is held in mating engagement with the helix elements of the rack member. <IMAGE>

Description

SPECIFICATION Flexible-rack and pinion-gear drive mechanism The present invention relates to a drive mechanism and particularly to a flexible-rack and pinion-gear drive mechanism which will supersede a conventional flexible-wire and pinion-gear drive mechanism which has been used in, for example, a window regulator system for a door structure of, for example, an automotive vehicle.

A known flexible-wire and pinion-gear drive mechanism which has been used in, for example, a window regulator system for a door structure of an automotive vehicle largely comprises a helical pinion gear to be rotated by a window manipulating handle mounted on the inner side of the door structure, and a flexible wire rack consisting of a core wire and a coil wire helically wound on, and fixedly secured to, the core wire. The pinion gear is in mating engagement with some helix elements of the coil wire so that the flexible wire rack is moved end-wise when the window manipulating handle is manually driven to turn to rotate the pinion gear.

One of the drawbacks inherent in a prior-art drive mechanism of this nature results from the use of the helical pinion gearwhich is costly to design and to machine.

Another drawback of such a drive mechanism is that the mating engagement between the pinion gear and the coiled wire of the flexible wire rack tends to become loose unless the coil wire is helically wound round the core wire with extreme precision. Manufacturing the flexible wire rack with such precision requires a large amount of production cost and, if the engagement between the pinion gear and the flexible wire rack fails to be satisfactorily firm, the pinion gear is caused to chatter on the wire rack or to skip over a helix element or elements of the coil wire when the gear is being driven for rotation on the wire rack.

The present invention contemplates the provision of a novel flexible-rack and pinion gear drive mechanism which will overcome these and other drawbacks of a conventional wire-rack and piniongear drive mechanism.

In accordance with the present invention, there is provided a flexible-rack and pinion-gear drive mechanism which comprises, in combination, a pinion gear rotatable about its center axis, and an elongated flexible rack member having a substantially circular cross section and a helically extending rib consisting of a plurality of helix elements which are elastically deformable to be at least partially spaced from one anotherforforming clearances between adjacent ones of the helix elements which are at least partially spaced from one another, the pinion gear and the flexible rack member being positioned with respect to each other so that the pinion gear is engageable through the above mentioned clearances with the helix elements which are at least partially spaced apart from one another.

The pinion gear thus forming part of the flexiblerack and pinion-gear drive mechanism is preferably constituted by a spur gear which is easy and economical to design and manufacture. In this instance, the drive mechanism may further comprise a hollow guide tube having at least one curved portion adjacent to the pinion gear and formed with an opening through which the pinion gear slightly protrudes into the guide tube, the flexible rack member extending through the hollow guide tube and having a curved portion in the curved portion of the guide tube, the helix elements of the curved portion of the rack member being spaced from each other along the outer ridge of the expanded side of the curved portion of the rack member for thereby forming the aforesaid clearances between the helix elements of the curved portion of the rack member.

The flexible-rack and pinion-gear drive mechanism proposed by the present invention is useful especially when incorporated into a window regulator system for a venicle door structure and will therefore be hereinafter described in detail as such.

It should, however, be borne in mind that the drive mechanism according to the present invention is not exclusively applied to such a system but can be used for various other purposes.

The drawbacks of a prior-art wire-rack and piniongear drive mechanism and the features and advantages of a flexible-rack and pinion-gear drive mechanism according to the present invention and a window regulator system incorporating the flexiblerack and pinion-gear drive mechanism will be rriore clearly understood from the following description taken in conjunction with the accompanying drawings, in which like reference numerals designate similar or corresponding members, elements and means and in which: Figure 1 is an inner side view of a vehicle door structure equipped with a window regulator system using a prior-art wire-rack and pinion-gear drive mechanism; Figure 2 is a fragmentary sectional view showing parts of the prior-art wire-rack and pinion-gear drive mechanism incorporated in the window regulator system shown in Figure 1.

Figure 3 is a view similar to Figure 1 but showing a vehicle door structure equipped with a window regulator system having incorporated therein an embodiment of the flexible-rack and pinion-gear drive mechanism according to the present invention.

Figure 4 is a fragmentary sectional view showing, to an enlarged scale, parts of the flexible-rack and pinion-gear drive mechanism incorporated in the window regulator system in the arrangement shown in Figure 3; Figure 5 is a fragmentary longitudinal sectional view showing portions of the hollow guide tube and the flexible rack member forming part of the flexiblerack and pinion-gear drive mechanism illustrated in Figure 3; Figure 6 is a horizontal sectional view showing, also to an enlarged scale, the arrangement in which the hollow guide tube and the flexible rack member of the drive mechanism illustrated in Figure 3 are connected to the door structure and the window glass thereof;; Figure 7 to 11 are views showing, each at least partly in longitudinal section, respective portions of various modifications of the flexible rack member constituted by a helically coiled steel wire in the arrangement shown in Figures 3 to 6; Figure 12 is a longitudinal sectional view showing a portion of a flexible rack member in the form of a steel wire helically wound on a core element for use as an alternative to the flexible rack member shown in the arrangement of Figures 3 to 6; Figure 13 is a longitudinal sectional view showing a portion of another modification of the flexible rack member provided in the flexible-rack and piniongear drive mechanism in the arrangement illustrated in Figures 3 to 6; and Figure 14 is a view similar to Figure 3 but showing another type of vehicle door structure equipped with a window regulator system having incorporated therein an embodiment of the flexible-rack and pinion-gear drive mechanism according to the present invention.

In Figures 1 and 2 of the drawings, a known wire-rack and pinion-gear drive mechanism is shown used in a window regulator system for a door structure 20 of an automotive vehicle. The door structure 20 per se comprises an inner panel member 21, an outer panel member (not shown) and a window glass 22 which is vertically movable through a space formed between the inner and outer panel members.

On the internal face of the inner panel member 21 is fixedly attached a base plate 23 having a window manipulating handle 24 rotatably mounted on the base plate 23. The handle 24 is securely connected to a pinion gear 25 which is rotatable about an axis normal to the inner panel member 21. A hollow guide tube 26 is fixedly attached at suitable locations to the panel member 21 by clamping members (not shown). The guide tube 26 has a straight portion extending in part on the base plate 23 and an acutely curved portion extending in part on a bracket 27 fixedly secured to a lower end portion of the window glass 22 as shown. The guide tube 26 has formed in the above-mentioned straight portion an opening 28 through which the pinion gear 25 slightly protrudes into the tube 26 as will be better seen from Figure 2.

A flexible wire rack 29 consisting of a core wire 30 and a coil wire 31 helically and fixedly wound on the core wire 30 at regular pitches is endwise movable in and through the holow guide tube 26 and is anchored at one end to the window glass 22 through the bracket 27. The coil wire 31 of such a flexible wire rack 29 is helically wound on the core wire 30 at regular pitches conforming to the pitches of the teeth of the pinion gear 25 and is in mating engagement with the teeth of the pinion gear 25 through the opening 28 in the tube 26.

When the handle 24 is manipulated to turn the pinion gear 25 in either direction about the axis of rotation thereof, the flexible wire rack 29 is driven to move endwise through the hollow guide tube 26.

The window glass 22 to which the wire rack 29 is anchored at one end is therefore moved upwardly or downwardly with respect to the door structure 20 depending upon the direction in which the handle 24 is turned about the axis of rotation of the gear 25.

One of the important requirements in the conventional wire-rack and pinion-gear drive mechanism thus constructed and arranged is that the pinion gear 25 in mesh with the coil wire 31 forming part of the flexible wire rack 29 must be constituted by a helical gearwhich is costly for designing and machining.

Another important requirement of such a drive mechanism is that the coil wire 31 of the wire rack 29 must be helically wound on the core wire 30 with upmost precision so that the pitches of the helix elements of the coil wire 31 be accurately in conformity to the pitches between the teeth of the helical pinion gear 25. If the coil wire 31 is not precisely wound on the core wire 30 and as a consequence the pitches of the helix elements of the coil wire 31 fail to be strictly in conformity to the pitches of the teeth of the pinion gear 25, there will result loose mating engagement between the pinion gear 25 and the coil wire 31 of the wire rack 29. This may cause the pinion gear 25 to chatter on the coil wire 31 or to skip a helix element or elements of the coil wire 31 when the gear 25 is being driven for rotation on the wire rack 29.

In order to meet these requirements of the priorart wire-rack and pinion-gear drive mechanism to a satisfactory degree, problems are encountered in that high costs and techniques are indispendable for the designing and machining of, especially, the helical pinion gear 25 and numerous steps are needed for the production and quality control of the wire rack 29.

Since, furthermore, the coil wire 31 wound on the core wire 30 is, in itself, subject to elongation or deformation when a pull or a compressive force is applied thereto, it is required to have the coil wire 31 wound on the core wire 30 throughout the total length of the core wire 30. This gives rise to an increase in the weight of the wire rack 29 per se and accordingly in an increase in the overall weight of the drive mechanism as a whole.

The present invention aims at the provision of a flexible-rack and pinion-gear drive mechanism which will overcome all these problems that have thus far been inherent in a conventional wire-rack and pinion-gear drive mechanism of the described nature. The present invention further contemplates provision of an improved window regulator system for a door structure of an automotive vehicle having such a flexible-rack and pinion-gear drive mechanism incorporated therein.

Embodiments of the flexible-rack and pinion-gear drive mechanism according to the present invention will be hereinafter described with reference to Figures 3 to 14 of the accompanying drawings.

Referring first to Figure 3 of the drawings, a flexible-rack and pinion-gear drive mechanism embodying the present invention is shown applied, by way of example, to a window regulator system for a door structure of an automotive vehicle as is the case with the prior-art wire-rack and pinion-gear mechanism described with reference to Figures 1 and 2. The door structure 20, is thus composed of an inner panel member 21, an outer panel member (not shown) partly spaced from the inner panel member 21 for forming a hollow space therebetween, and a window glass 2 which is vertically movable through the hollow space between the inner and outer panel members.The window glass 22 is herein assumed, by way of example, to be of the framed type and is provided with a window frame or sash 32 having portions respectively extending along upper, front and rear edges of the window glass 22 and two lower portions 32a and 32b respectively attached to the inner panel member 21 and extending downwardly as indicated in dot-and-dash lines in Figure 3.

The lower portions 32a and 32b of the window sash 32 are arranged in such a manner as to be capable of guiding the upward and downward movement of the window glass 22 with respect to the door structure 20. The window glass 22 is therefore movable upwardly and downwardly on a predetermined plane between the inner and outer panel members of the door structure 20.

The window regulator system provided for the door structure thus constructed and arranged comprises a base plate 23 which is fixedly attached to the internal face of the inner panel member 21 of the door structure 20 by suitable fastening means such as bolts and nuts (not shown). The "internal" face of the inner panel member 21 as herein mentioned refers to that face of the panel member 21 which is inboard of the door structure 20 per se, while the "inner" panel member 21 refers to that component panel of the door structure 20 which is in-board of the vehicle compartment.

The window regulator system shown in Figure 3 further comprises a window manipulating handle 24 which is mounted on the inner panel member 21 of the door structure 20 in such a manner that the handle 24 can be manipulated from the interior of the vehicle compartment. The window manipulating handle 24 has an end portion connected to, or integral with, a shaft 33 having a pinion gear 34 carried thereon as shown in Figure 4 of the drawings. The pinion gear 34 is positioned between the base plate 23 and the plane along which the window glass 22 is to be moved up and down within the space between the inner and outer panel members of the door structure 20.The shaft 33 thus carries the window manipulating handle 24 at one end thereof and the pinion gear 34 at the other end thereof and is rotatable with respect to the door structure 20 about its center axis which is substantially normal to the above mentioned plane. Thus, the window manipulating handle 24 and the pinion gear 34 are rotatable with the shaft 33 with respect to the door structure 20 about the center axis of the shaft 33. The pinion gear 34 forming part of the flexible-rack and piniongear drive mechanism embodying the present invention is constituted by a spur gear and is associated with suitable reverse-turn preventive means (not shown) operative to prevent the gear 34 from being turned in a direction opposite to the direction in which the gear 34 is driven for rotation by the handle 24.

The flexible-rack and pinion-gear drive mechanism incorporated in the window regulator system shown in Figure 3 further comprises an elongated, hollow guide tube 35 extending in a generally J-shaped configuration on the internal face of the inner panel member 21 of the door structure 20. The guide tube 35 has a curved portion 35a (Figure 4) extending on the base plate 23 and a substantially straight upper portion 35b (Figure 5) directed upwardliy toward the lower end of the window glass 22, viz., extending substantially in parallel with the two lower portions 32a and 32b of the window sash 32. The guide tube 35 has in its curved portion 35a an opening 36 through which the pinion gear 34 slightly projects into the tube 35 as will be seen from Figure 4.The guide tube 35 is fixedly attached at suitable locations thereof to the internal face of the inner panel member 21 of the door structure 20 by fixtures 37 secured to the panel member 21. In Figure 6, the hollow guide tube 35 is shown to be attached at each of these locations by a pair of fixtures 37 each of which is fastened to the internal face of the inner panel member 21 by means of a bolt 38 and a nut 39 and which is secured to the tube. Furthermore, the guide tube 35 is welded or brazed to the base plate 23 along its curved portion extending on the base plate 23 so that the curved portion 35a of the tube 35 is fixed with respect to the base plate 23 and accordingly to the shaft 33 carrying the pinion gear 34.For the reason that will be understood as the description proceeds, the straight upper portion 35b of the guide tube 35 is formed with a longitudinal slot 40 which is open toward the previously mentioned plane on which the window glass 22 is vertically movable between the inner and outer panel members of the door structure 20 as will be seen from Figure 6.

The flexible-rack and pinion-gear drive mechanism comprising the hollow guide tube 35 further comprises an elongated flexible rack member 41 which is indicated by broken lines in Figure 3. As indicated in partto enlarged scales in Figure 4 and 5, the flexible rack member 41 provided in the embodiment of Figures 3 to 6 is constituted by a helically coiled steel wire 42 which is elastically expansible longitudinally thereof. The coiled steel wire 42 movable endwisely extends in and through the hollow guide tube 35 and is securely connected at the leading end of the straight upper portion thereof to a lower end portion of the window glass 22 by fastening means which is schematically indicated at 43 in Figure 3.As is illustrated in detail in Figure 6, the fastening means 43 comprises a pair of brackets 44 welded or brazed as at W to a straight upper portion of the flexible rack member 41 adjacent to the upper end of the particular portion. The brackets 44 project radially outwardly from the coiled steel wire 42 toward the inner face of the window glass 22 through the previously mentioned longitudinal slot 40 in the portion 35b of the tube 35 and are securely attached to the inner face of the window glass 22 by bolts 45 and nuts 46. The slot 40 in the straight upper portion 35b of the guide tube 35 is elongated in the longitudinal direction in the portion 35b of the tube 35 so that the brackets 44 are movable through the slot 40 longitudinally of the guide tube 35. Thus, the window glass 22 and the coiled steel wire 42 constituting the flexible rack member 41 are movable together longitudinally of the straight upper portion 35b of the guide tube 35, viz., in upward and downward directions substantially parallel with the lower portions 32a and 32b of the window sash 32.

The construction and arrangement of the fastening means 43 above described is merely for the purpose of illustration and may therefore be modified in numerous manners insofar as the coiled steel wire 42 can be fixedly anchored at, or adjacent, its uppermost end to the window glass 22 in such a manner as to be free to move longitudinally of the straight upper portion 35b of the hollow guide tube 35.

The coiled steel wire 42 constituting the flexible rack member 41 has, throughout the length thereof or at least over its portion extending through the curved portion 25a of the guide tube 35, a substantially equilaterally trapezoidal cross section which is reduced radially outwardly of the generally tubular construction of the wire 42 as will be seen in Figure 4. Furthermore, the coiled steel wire 42 has pitches of helix which are such that the individual helix elements of the wire 42 having such a cross section are contacted by or held in close proximity to one another at the enlarged, radially inner ends or bases of the cross sections thereof when the wire 42 is maintained in a slackened state substantially free from stresses, as will be seen from the illustration of Figure 5.

In the curved portion 35a of the hollow guide tube 35, the coiled steel wire 42 is subjected to a bending stress and is thereby forced to curve along the curved portion 35a of the guide tube 35 as shown in Figure 4. The helix elements constituting such a curved portion of the coiled steel wire 42 are forced to be spaced from one another along an outer ridge of the expanded side of the curved portion of the wire 42. The result is that gaps or clearances are formed between the adjacent ones of the helix elements forming the curved portion of the coiled steel wire 42 along the outer ridge of the particular portion. In Figure 4 of the drawings, one of such gaps or clearances is indicated by reference character G which represents the gap or clearance formed between adjacent helix elements H and H' of the coiled steel wire 42.Thus, the coiled steel wire 42 is engaged by the pinion gear 34 in such a manner that one of the teeth of the pinion gear 34 slightly protruding into the hollow guide tube 35 through the opening 35 in the tube 35 enters the gap or clearance G in the coiled steel wire 42. When the pinion gear 34 is driven for rotation in either direction about the center axis of the shaft 33, that tooth of the gear 34 which has been fitted in the gap or clearance G is caused to ride on the helix element H or H' and forces the curved portion of the coiled steel wire 42 to move through the curved portion 35a of the guide tube 35 in a direction indicated by arrowX or a direction indicated by arrow Yin Figure 4 depending upon the direction of rotation of the pinion gear 34.

While the above mentioned tooth of the pinion gear 34 is being thus moved out of the gap or clearance G, a trailing tooth of the rotating pinion gear 34 is caused to enterthe gap or clearance formed be tween the helix elements respectively next to the above mentioned helix elements H and H' of the coiled steel wire 42. This causes the curved portion of the coiled steel wire 42 to further move through the curved portion 35a of the hollow guide tube 35.

In this manner, the individual helix elements constituting the curved portion of the coiled steel wire 42 being moved through the curved portion 35a of the guide tube 35 are successively engaged one after another by the teeth of the pinion gear 34 being driven for rotation about the center axis of the shaft 33. As a consequence, the rotating pinion gear 34 is constantly held in mating engagement with the elements of the curved portion of the coiled steel wire 42, which is therefore forced to move in its entirety through the hollow guide tube 35.When the helix elements of the coiled steel wire 42 thus moved endwise through the hollow guide tube 35 are moved out of the curved portion 35a of the guide tube 35 into a straight or less curved portion of the tube 35, the helix elements are allowed to restore their initial positions relative to one another and are thus contacted by or held in close proximity to one another at the enlarged, radially inner ends or bases of the cross sections thereof. For this reason, those helix elements of the coiled steel wire 42 which have been moved out of the curved portion 35a of the hollow guide tube 35 cannot be engaged by the pinion gear 34.It will be apparent that the radius of curvature of the curved portion 35a of the hollow guide tube 35 should be selected so that the coiled steel wire 42 being passed through the particular portion of the guide tube 35 cannot be deformed beyond the limit of elasticity of the wire 42.

When the window manipulating handle 24 is manually turned in either direction about the center axis of the shaft 33, the pinion gear 34 is driven for rotation also about the axis of the shaft 33 and, in turn, drives the coiled steel wire 42 to endwise move through the hollow guide tube 35 in the direction of the arrow X or Y shown in Figures 4 and 5 depending upon the direction in which the handle 24 is turned.

The axial movement of the coiled steel wire 42 through the hollow guide tube 35 fixed to the door structure 20 is accompanied by downward or upward movement of the window glass 22 with respect to the door structure 20 by means of the fastening means 43 provided between the window glass 22 and the coiled steel wire 42. Such movement of the window glass 22 is guided by the front and rear lower portions 32a and 32b of the window sash 32 attached to the inner panel member 21.

In the arrangement shown in Figure 3, it is assumed that the window glass 22 is to be moved upwardly with respect to the door structure 20 by the axial movement of the coiled steel wire 42 in the direction of the arrow X in Figures 4 and 5 and to be moved downwardly with respect to the door structure 20 by the axial movement of the coiled steel wire 42 in the direction of the arrow Yin Figures 4 and 5. When the coiled steel wire 42 is moved endwise in the direction of the arrow X through the hollow guide tube 35 which is fixed to the door structure 20, the weight of the window glass 22 being moved upwardly with respect to the door structure 20 is at least partially borne by that portion of the coiled steel wire 42 which intervenes between the pinion gear 34 and the fastening means 43 interconnecting the window glass 22 and the wire 42.The coiled steel wire 42 being moved in the direction of the arrow Xis for this reason subjected to a compressive stress exerted by the weight of the window glass 22. When, conversely, the coiled steel wire 42 is moved endwise in the direction of the arrow Y through the hollow guide tube 35, that portion of the coiled steel wire 42 which intervenes between the pinion gear 34 and the fastening means 43 is axially subjected to a pull resulting from a resistance to the downward movement of the window glass 22. The coiled steel wire 42 being moved in the direction of the arrow Y is therefore subjected to a tensile stress resulting from such a resistance to the downward movement of the window glass 22.

Since, in this instance, the resistance to the downward movement of the window glass 22 is to some extent offset by the weight of the window glass 22 and, for this reason, the tensile stress to be produced in the coiled steel wire 42 during downward movement of the window glass 22 is far smaller in magnitude than the compressive stress to be produced in the wire 42 during upward movement of the window glass 22. Accordingly, the coiled steel wire 42 is capable of sufficiently taking up the tensile stress to be produced therein during downward movement of the window glass 22.

When, on the other hand, the coiled steel wire 42 is subjected to a compressive stress during upward movement of the window glass 22, the individual helix elements constituting that portion of the wire 42 which intervenes between the pinion gear 34 and the fastening means 43 are held in close contact with one another at the enlarged, radially inner ends or bases of the cross sections thereof. That portion of the coiled steel wire 42 which is formed by such helix elements is substantially similar in effect to a rigid, hollow pipe and is for this reason capable of withstanding the compressive force applied to the wire 42 during upward movement of the window glass 22.

Figures 7 to 13 of the drawings exemplify various modifications of the flexible rack member 41 which is constituted by the coiled steel wire 42 in the embodiment hereinbefore described with reference to Figures 3 to 6.

Of the modifications shown in Figures 7 to 13, each of the flexible rack members 41 illustrated in Figures 7 to 11 consists exclusively of a helically coiled steel wire.

Referring to Figure 7, the flexible rack member 41 is shown constituted by a helically coiled steel wire 42a having an equilaterally triangular cross section which is reduced in a V-shaped form radially outwardly of the generally tubular construction of the coiled steel wire 42a. The coiled steel wire 42a has pitches of helix which are such that the individual helix elements of the wire 42a having such a triangular cross section are contacted by or held in close proximity to one another at the enlarged, radially inner ends or bases of the cross sections thereof when the wire 42a is maintained in a slackened state substantially free from stresses, as indicated by full lines in Figure 7.When the coiled steel wire 42a thus configured is subjected to a bending stress and is thereby forced to partially curve as indicated by phantom lines in Figure 7, the helix elements constituting the curved portion fo the wire 42a are spaced from one another and form gaps or clearances therebetween along the outer ridge of the expanded side of the curved portion. The coiled steel wire 42a can thus be engaged through such gaps or clearances by the teeth of a gear constructed and arranged similarly to the pinion gear in the embodiment of the drive mechanism described with reference to Figures 3 to 6.

Turning to Figure 8, the flexible rack member 41 is shown consisting of a helically coiled steel wire 42b having a cross section which is reduced radially outwardly of the generally tubular construction of the wire 42b and which has a pair of flank profiles each consisting of an involute curve similar to the flank profiles of an involute gear tooth. The flexible rack member 41 thus constituted by such a coiled steel wire 42b is also operable essentially similarly to the flexible rack member 41 constituted by the coiled steel wire 42 in the embodiment of the drive mechanism described with reference to Figures 3 to 6, as will be readily understood.

The flexible rack member 41 shown in Figure 9 of the drawings consists of a helically coiled steel wire 42c having a rectangular cross section. The wire 42c is coiled in such a manner as to have predetermined pitches e1 when the wire 42c is maintained in a slackened state substantially free from stresses.

Thus, the coiled steel wire 42c of the flexible rack member 41 shown in Figure 9 is axially not only expansible but also compressible. When such a coiled steel wire 42c is subjected to a compressive force in the axial direction thereof, the generally tubular construction thereof is axially contracted elastically until the individual helix elements of the wire are brought into close contact with one another.

When the helix elements of the coiled steel wire 42c are thus held in close contact with one another, the tubular construction of the wire 42c can no longer be contracted axially. When the flexible rack member 41 constituted by such a coiled steel wire 42c is used in a window regulator system for a door structure of an automotive vehicle as in the arrangement shown in Figure 3, the rack member 41 will be moved endwise with respect to the door structure with the individual helix elements of the coiled steel wire 42c held in contact with or only slightly spaced apart from one another during upward movement of the window glass of the door structure.

Referring further to Figure 10 ofthe drawings, the flexible rack member 41 is shown consisting of a helically coiled steel wire 42d having a substantially circular cross section. In this instance, the steel wire 42d is helically coiled at pitches which are such that the individual helix elements of the wire 42d are held in contact with one another when the coiled steel wire 42d is maintained in a slackened state which is substantially free from stresses.

The flexible rack member 41 shown in Figure 11 is constituted by a helically coiled steel wire 42e having an elliptical cross section which is wider in radial directions of the generally tubular configuration of the rack member 41 than in the axial direction of such a configuration. The steel wire 42e is helically coiled in such a manner as to have predetermined pitches e2 when the wire 42e is maintained substantially free from stresses. The flexible rack member 41 consisting of such a coiled steel wire 42e is, thus, adapted to achieve effects essentially similar to those attainable by the flexible rack member 41 constituted by the coiled steel wire 42c shown in Figure 9.

On the other hand, the flexible rack member 41 shown in Figure 12 of the drawings is provided in combination with an elongated, flexible core element 47 having a substantially circular cross section.

The flexible rack member 41 in the arrangement herein shown is per se constituted by a helically coiled steel wire 42f having a substantially squareshaped cross section and chamfered edges. The steel wire 42f is helically coiled round the peripheral surface of the core element 47 in such a manner as to have predetermined pitches e3 Thus, the core element 47 serves as a reinforcementforthe coiled steel wire 42f and thereby enables the wire 42fto withstand the larger compressive and tensile stresses when used in a window regulator system for a door structure of an automotive vehicle.For this reason, the coiled steel wire 42fcan be used in such a manner as to be subjected to a tensile stress of a considerable degree when the window glass of the door structure provided with such a window regulator system is to be moved upwardly with respect to the door structure.

It will be apparent that each of the flexible rack members 41 shown in Figures 4 to 11 may also be provided in combination with a core element similar to the core element 47 in the arrangement of Figure 12 for achieving the advantage of such reinforcement member.

In the flexible rack members 41 shown in Figures 9,11 and 12, the pitches e1, e2 and e3 between the individual helix elements of the coiled steel wires 42c, 42e and 42f, respectively, are preferably selected so that the helix elements having such pitches will not allow entry of a tooth of a spur gear (not shown) into the gap or clearance between adjacent two of the helix elements when each of the coiled steel wires is in a slackened condition sub stantiallyfree from stresses.When each of these coiled steel wires 42c, 42e and 42fits partially curved, the pitches between the individual helix elements constituting the curved portion are enlarged along the outer ridge on the expanded side of the curved portion and allow entry of teeth of a spur gear into the gaps or clearances between these helix elements so as to provide established mating engagement between the spur gear and each of the coiled steel wires.

Turning to Figure 13 of the drawings, the flexible rack member 41 is shown consisting of an elongated flexible member 42g constructed of an elastic synthetic resin and having a substantially circular cross section. The elongated flexible member 42g has a peripheral wall formed with a helically extending groove 48 having, for example, a V-shaped cross section and is accordingly formed with a helically extending thread 49 having a substantially equilaterally trapezoidal cross section which is reduced radially outwardly of the cross section of the member 42g. The width of the helical groove 48 is such that the groove will not allow entry thereinto of a tooth of a spur gear (not shown) when the flexible member42g is in a slackened state substantially free from stresses.When the flexible member 42g is subjected to a bending stress and is thereby partially~ curved, the groove 48 in the curved portion of the flexible member 42g opens wider along the outer ridge of the particular portion and admits teeth of the spur gear into the wider open portion of the groove 48 so as to establish mating engagement between the gear and the flexible member 42g.

It has been assumed that the flexible-rack and pinion-gear drive mechanism according to the present invention is incorporated into a window regulator system for a vehicle door structure having a window glass of the framed type. This is, however, merely for the purpose of illustration and it will be apparent that the drive mechanism proposed by the present invention can be constructed as part of a window regulator system for a vehicle door structure having a window glass of the frameless type. An example of such a window regulator system is illustrated in Figure 14.

Referring to Figure 14 a window glass 22 forming part of a door structure 20 of an automotive vehicle is shown having its edges exposed, with an exception of a portion of its lower edge which is in part contacted by a support plate 50. The support plate 50 is securely attached to the inner face of a lower end portion of the window glass 22 by fastening means (not shown). An elongated, straight guide rod 51 is fixedly connected to the inner panel member 21 of the door structure 20 and is engaged by a guide member 52 which is connected to, or integral with, the support plate 50. The guide member 52 is slidable on the guide rod 51 longitudinally of the rod 51 with respect to the door structure 20. The guide rod 51 extends in a direction substantially parallel with the direction in which the window glass 22 is to be moved upwardly and downwardly with respect to the door structure 20.

The window regulator system shown in Figure 14 is constructed and arranged essentially similarly to its counterpart shown in Figure 3 except that the flexible rack member 41 in the arrangement of Figure 14 is anchored at the leading end of its straight upper portion to the above mentioned support plate 50 by suitable fasening means 43'.

Other component members and elements of the window regulator system provided in the arrangement of Figure 14 are similar to their respective counterparts of the window regulator system of Figure 3 and are therefore represented by like reference numerals.

When the window manipulating handle 24 is manually turned in either direction in the door regulator system of the arrangement shown in Figure 14, the flexible rack member 41 is moved endwise through the hollow guide tube 35 and causes the window glass 22 to move upwardly or downwardly with respect to the door structure 20 depending upon the direction in which the handle 24 is turned. In this instance, the window glass 22 is moved upwardly or downwardly in a direction substantially parallel with the longitudinal direction of the guide rod 51 under the guidance of the guide member 52 sliding on the guide rod 51.

The spur gear to be used as the pinion gear in the flexible-rack and pinion-gear drive mechanism according to the present invention may be fabricated by machining a steel blank by the use of a machine tool or by punching out such a gear from a blank in a power press. The work produced in either of these manners is then preferably quenched, tempered, carburized, nitrided, induction heated and/or sulphurized so as to add to the mechanical strength of the work and the surface resistance to wear and abrasion. If desired, the spur gear may be constructed of a hard, wear-resistive synthetic resin.

On the other hand, the hollow guide tube also forming part of the drive mechanism according to the present invention is, especially when constructed of metal, preferably coated with a layer of a synthetic resin on its inner peripheral surface. The inner peripheral surface of the hollow guide member is inevitably contacted in part by the flexible rack member extending through the guide tube since the rack member is endwise deformed by the weight of, for example, the window glass supported by the rack member in weight-transmitting relationship thereto and any other external forces which may be exerted on the rack member.When the flexible rack member is driven to move endwise through the hollow guide tube by, for example, turning the window manipulat ing handle of a door window regulator system, the rack member thus partly contacting the inner peripheral surface of the guide tube slides on the contact areas of the surface, producing noises and frictional resistances between the rack member and the contact areas of the guide tube. The coating of synthetic resin applied to the inner peripheral surface of the hollow guide tube will contribute to minimizing such noises and frictional resistances.

For the same purpose, the flexible rack member may also be coated with such a layer of a synthetic resin especially on its external surface portions.

As will have been understood from the foregoing description, the flexible-rack and pinion-gear drive mechanism according to the present invention basically comprises, in combination, a pinion gear such as the pinion gear 34 shown in Figures 3 and 4, and an elongated flexible rack member 41 having a substantially circular cross section and a helically extending rib consisting of a plurality of helix elements which are elastically deformable to be at least partially spaced from one another for forming gaps or clearances between adjacent ones of these helix elements. The pinion gear such as the gear 34 and the flexible rack member 41 are positioned with respect to each other in such a manner that the pinion gear is engageable through the above mentioned gaps or clearances with the helix elements which are at least partially spaced from one another.

The rib above mentioned is formed, in each of the embodiments of Figures 3 to 12, by a radially outer portion of the helically coiled wire 42 or each of the helically coiled wire 42a to 42f or by the helical thread 49 in the embodiment of Figure 13. In the drive mechanism thus constructed, the pinion gear is enabled to be constantly and with certainty held in mating engagement with the helix elements of the flexible rack member when such helix elements form a bent or curved portion of the rack member subjected to a bending stress. Forthis reason, the drive mechanism according to the present invention features, among other things, freedom from the occurrence of chattering between the pinion gear and the flexible rack member which can be reliably driven to travel by the rotation of the pinion gear.

Another feature of the drive mechanism according to the present invention is that the pinion gearforming part of the mechanism can be constituted by a spur gear which is economical to design and to manufacture and which can be manufactured in a reduced number of steps for production and quality control.

When the drive mechanism according to the present invention comprises a hollow guide tube having at one curved portion which is in part open adjacent to the pinion gear as is the case with the guide guide tube 35 in each of the arrangements shown in Figures 3 and 14, the flexible rack member extending through the guide tube can be moved endwise accurately along the guide tube, especially along the curved portion of the tube.

When, furthermore, the flexible-rack and piniongear drive mechanism according to the present invention is used in a window regulator system of an automotive vehicle, the door structure including a window glass can be designed and engineered with ease and can be constructed without strictly taking the internal space requirement of the door structure into account. These will contribute to reduction of the weight of the door structure and ultimately to reduction of the overall weight of an automotive vehicle as a whole.

Claims

1. A flexible-rack and pinion-gear drive mechanism comprising, in combination: a pinion gear rotatable about its center axis; and an elongated flexible rack member having a substantially circular cross section and a helically extending rib consisting of a plurality of helix elements which are elastically deformable to be at least partially spaced from one another for forming clearances between adjacent ones of said helix elements which are at least partially spaced apart from one another, said pinion gear and said flexible rack member being positioned with respect to each other so that said pinion gear is engageable through said clearances with said helix elements which are at least partially spaced apart from one another.

2. A flexible-rack and pinion-gear drive mechanism as set forth in claim 1, in which said pinion gear is constituted by a spur gear.

3. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 2, further comprising a hollow guide tube having at least one curved portion adjacent to said pinion gear and formed with an opening through which said pinion gear slightly protrudes into said guide tube, said flexible rack member extending through said hollow guide tube and having a curved portion in said curved portion of said guide tube, said helix elements of said curved portion of said rack member being spaced from each other along the outer ridge of the expanded side of said curved portion of said rack memberforthereby forming said clearances between said helix elements of said curved portion of said rack member.

4. A flexible-rack and pinion-gear drive mechanism as set forth in claim 1,2 or 3, in which said helix elements of said rib have therebetween pitches which are such that said helix elements of said rib are held in contact with one another when said flexible rack member is maintained in a slackened state substantially free from stresses.

5. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 1,2 or 3, in which said helix elements of said rib have therebetween pitches which are such that said helix elements of said rib are held in proximity to one another when said flexible rack member is maintained in a slackened state substantially free from stresses.

6. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 1,2 or 3, in which said flexible rack member consists of a helically coiled elastic wire having a radially outer portion constituting said rib.

7. A flexible-rack and pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a substantially equilateraly trapezoidal cross section which is reduced radially outwardly of said flexible rack member.

8. A flexible-rack and pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a substantially equilaterally triangular cross section which is reduced radially outwardly of said flexible rack member.

9. A flexible-rack and pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a cross section which is reduced radially outwardly of said flexible rack member and which has a pair of flank profiles each consisting of an involute curve.

10. Aflexible-rackand pinion-geardrive mechanism as set forth in claim 7,8 or 9, in which said helix elements of said coiled elastic wire have therebetween pitches which are such that said helix elements of said wire are held in contact with one another at the enlarged, radially inner ends of the helix elements when said flexible rack member is maintained in a slackened state substantially free from stresses.

11. A flexible-rack and pinion-gear drive mechanism as set forth in claim 7,8 or 9, in which said helix elements of said coiled elastic wire have therebetween pitches which are such that said helix elements of said wire are held in proximity to one another at the enlarged, radially inner ends of the helix elements when said flexible rack member is maintained in a slackened state substantially free from stresses.

12. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a substantially rectangular cross section.

13. A flexible-rack and pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a substantially circular cross section.

14. A flexible-rack and pinion-gear drive mechanism as set forth in claim 6, in which said coiled elastic wire has a substantially elliptical cross section.

15. A flexible-rack and pinion-gear drive mechanism as set forth in claim 13, in which said elliptical cross section of said coiled elastic wire has, in radial direction of said rack member, a measurement which is iargerthan the measurement of said wire in axial direction of said rack member.

16. A flexible-rack and pinion-gear drive mechanism as set forth in any one of claims 7 to 9 or any one of claims 12 to 15, in which said helix elements of said coiled elastic wire are spaced from one another at predetermined pitches when said flexible rack member is maintained in a slackened state substantially free from stresses.

17. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 6, further comprising an elongated, flexible core element round which said elastic wire is helically coiled.

18. A flexible-rack and pinion-gear drive mechanism as set forth in claim 17, in which said coiled elastic wire has a substantially rectangular cross section and has chamfered edges.

19. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 1,2 or 3, in which said flexible rack member is constructed of an elastic synthetic resin and is formed with a helically extending groove forming a helically extending thread which constitutes said rib, said clearances being formed by helix portions of said groove and helix elements of said rib being constituted by helix portions of said thread.

20. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 1,2 or 3 and as incorporated in a window regulator system for a door structure including a window glass movable with respect to said door structure, said window regulator system comprising a base plate secured to said door structure and having said pinion gear mounted thereon for rotation about said center axis thereof and fastening means securely connecting said flexible rack member adjacent to one end thereof to said window glass.

21. A flexible-rack and pinion-gear drive mechanism as set forth in claim 3 and as incorporated in a window regulator system for a door structure including a window glass movable with respect to said door structure, said window regulator system comprising a base plate secured to said door structure and having said gear mounted thereon for rotation about said center axis thereof, and fastening means securely connecting said flexible rack member adjacent to one end thereof to said window glass, said hollow guide tube being secured to said door structure and having said curved portion of said tube secured to said base plate.

22. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 1,2 or 3 and as incorporated in a window regulator system for a door structure including a window glass movable on a predetermined plane in two opposite directions with respect to said door structure, said flexible rack member being movable along a path having a substantially straight portion extending on a plane substantially parallel with said predetermined plane, said rack member being anchored at one end thereof to said window glass for being subjected to a compressive force when said window glass is moved in one of said two opposite directions and to a tensile force when the window glass is moved in the other direction.

23. Aflexible-rackand pinion-gear drive mechanism as set forth in claim 3 and as incorporated in a window regulator system for a door structure including a window glass movable with respect to said door structure in substantially opposite vertical directions, said window regulator system comprising a base plate secured to said door structure and having said pinion gear mounted thereon for rotation about said center axis thereof and fastening means securely connecting said flexible rack member adjacent to one end thereof to said window glass, said guide tube having a substantially straight portion upwardly terminating adjacent said window glass and said rack member being partially movable and connected to said fastening means through said straight portion so that said rack member is subjected to a compressive force when said window glass is moved downwardly with respect to said door structure and to a tensile force when said window glass is moved upwardly with respect to said door structure.

24. Aflexible-rackand pinion-geardrive mechanism substantially as described with refer ence to Figures 3 to 13, or Figure 14, of the accompanying drawings.