FR3087185A1 - REAR WHEEL SUSPENSION BIKE FRAME - Google Patents

Abstract

Rear wheel suspension bicycle frame comprising a base in two sections articulated to each other by a horizontal pivot axis (101) to define a suspension geometry with virtual pivot point, characterized in that one of the two sections has a recess (R1, R2) adjusted to receive a body (103, 104) fitted to the axis, the recess (R1, R2) and the body being shaped so that the axis (101) can be placed at two different ribs (A, A ') of the section of the base carrying the recess (R1, R2) by modifying the angular indexing of said body (103, 104) with respect to the axis (101) during reassembly of said axis (101).

Description

BICYCLE WITH SUSPENSION OF REAR WHEEL [0001] The invention is in the field of bicycles, in particular mountain bikes (MTB).

[0002] Current mountain bikes often have front suspension and rear suspension and are then called "all suspended" mountain bikes. Different forms of rear suspension have been developed, and provide for the installation of a shock absorber between the front triangle, formed by the upper body tube, the lower body tube and the seat tube, on which the cyclist leans, and the rear wheel axle. They all require the rotation of the rear triangle formed by the stay cables and the bases opposite the front triangle.

The front triangle remains undeformable, but the rear triangle can, in sophisticated versions, be deformed, by the introduction of additional joints, such as for example a four-bar mechanism, using rods connecting the shrouds to the tube saddle, and a rear pivot, located near the axis of the rear wheel, on the bases.

The combination of two axes of rotation between the rear wheel axle and the front triangle defines a suspension geometry with virtual pivot point.

Mountain bikes of different sizes exist. Long 26-inch wheels have been proposed, perceived as offering satisfactory handling and nervousness, for a contained weight. The 29-inch wheels that appeared later provide more comfort by clearing uneven terrain, while having a larger dimension for attacking obstacles, as well as increased stability and grip. However, their construction is heavier, and the inertia of the bicycle is increased.

Third solution, the 27.5 inch wheels have intermediate characteristics which make them a standard of choice currently, in parallel with the 29 inch wheels.

There is therefore currently a growing interest in different wheel standards, and discerning riders wish to benefit, depending on the route, from one wheel size or another wheel size. It is even desired to be able to drive with a front wheel of one size and a rear wheel of another size, in certain circumstances. Of course, changing the wheel should not affect the position of the cyclist once mounted on the bicycle.

Conventionally, in order to switch from wheels of one size to wheels of another size, to avoid the driver finding himself in an improper position, it is necessary to change the frame. Also, if a wheel larger than the one originally intended for the frame is used, the rear wheel may touch the rear bases or the bottom bracket, and it is often necessary to change the fork to make it compatible with the wheel before bigger.

The invention aims to solve these difficulties by providing a rear wheel suspension bicycle frame comprising a base in two sections hinged to one another by a horizontal pivot axis to define a point suspension geometry virtual hub.

This framework is special, because one of the two sections has a recess adjusted to receive a body fitted to the horizontal pivot axis, the recess and the body being shaped so that the axis can be placed at two different sides of the section of the base carrying the rejection by modification of the angular indexing of said body with respect to the axis during reassembly of said axis.

Thanks to these principles, it is easy, from an ATV equipped with a rear wheel of a certain diameter, to disassemble the wheel, disassemble the rear pivot axes and modify the orientation of the fitted bodies. sort of lengthen or shorten the dimension, raise the rear pivot axes, and place wheels of another diameter suitable for the modified dimension. These modifications can be carried out quickly between two races.

According to optional characteristics:

- the recess is oblong with a main axis locally parallel to the axis of the base;

- The pivot axis is formed by a screw-nut system, and the nut is shaped to constitute such a body fitted to the axis which can be placed in two different orientations in such a recess then placed on the 'one of the external faces of the sections;

- The frame includes a part to be fitted fitted on the axis and between the two sections, shaped to constitute such a body fitted on the axis which can be placed in two different orientations in such a recess then placed on the one of the internal faces of the sections;

- The frame further comprises a removable spacer to define two possible heights of the fork vis-à-vis the handlebars;

- the rear wheel shock absorber is articulated at its ends respectively to the oblique tube and to the seat stays, the seat stays being articulated to the seat tube by connecting rods;

- The oblique tube includes a battery housing for an electric bicycle, with access to the battery on the lower side of the oblique tube.

The invention also relates to an all-terrain bicycle equipped with a frame as presented above.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, made with reference to the appended drawings given solely by way of example illustrating a embodiment of the invention and in which:

- Figure 1 is a view of a mountain bike frame (mountain bike) according to an embodiment of the invention;

- Figure 2 is a view of an operating aspect of the frame of Figure 1;

- Figures 3 and 4 are views of another operating aspect of the frame of Figure 1;

- Figures 5 to 9 are views of a particular aspect of the invention, and Figures 10 and 11 show the implementation of this particular aspect.

In Figure 1, there is shown a bicycle frame according to an embodiment of the invention. This frame is for example made of aluminum.

The frame 1 is equipped with a suspension for the rear wheel, and is shown in the figure without the fork which, for its part, carries the suspension for the front wheel.

The main triangle of the frame is constituted by the upper body tube 10 (upper tube), the lower body tube 11 (oblique tube) and the seat tube 12. The lower body tube 11 and the seat tube 12 are connected by the motor support 13 and the lower body tube 11 and the upper body tube 10 meet and are connected, beyond their junction, to the steering tube 14, in which the bicycle fork (not shown) ) is inserted and above which the stem (not shown) is placed.

The seat tube 12 extends beyond its junction point with the upper body tube 10, and is dimensioned to accommodate the seatpost (not shown) in its internal space. In the model shown, the top body tube 10 is not strictly horizontal but slightly tilted towards the rear of the bike. The lower body tube 11 is, in turn, dimensioned to receive in its internal volume a battery for an electric bicycle, removable by the lower face of the lower body tube 11 which is hollowed out.

A pivot axis 31 said main pivot is mounted between the front triangle and the right and left base tubes, 20 and 21. The main pivot axis 31 is placed at the bottom of the seat tube 12 above the motor support 13 perpendicular to the median plane of the bicycle.

A damper 32 is present between the lower body tube 11 and the right and left shrouds 22 and 23. The damper 32 is fixed to the lower body tube 11 at about% of its length, on the side of the steering tube 14 and at a distance from the engine support 13. The guy 22 and the guy 23 both have a bore 33, respectively 34 for receiving the axis of rotation of the rear wheel (not shown) at their respective ends opposite to the shock absorber 32, that is to say at the rear of the frame 1 opposite the head tube 14.

The stays 22 and 23 are not fixed directly to the seat tube 12, the latter being placed between said stays 22 and 23 which approach each other after having doubled the seat tube 12 in the direction front of the bike. The shrouds 22 and 23 are connected to each other by a shaft transverse to the median plane of the bicycle and on which the damper 32 is mounted in rotation. The shrouds 22 and 23 are also articulated with respect to the seat tube 12 by means of a link in two parts, right and left 24 and 25.

The lower ends of these two parts 24 and 25 of the link are articulated to the seat tube 12 by a transverse axis common to these two links and positioned at mid-height between the engine support 13 and the upper body tube 10, on the front of the seat tube 12. Their upper ends are placed on the seat corresponding to the right of the seat tube 12, slightly towards the rear of the latter, and articulated respectively with the two seat stays, by axes of pivot parallel to the other pivot axes, that is to say transverse to the median plane of the bicycle.

The links 24 and 25 allow the guiding of the shrouds 22 and 23 which carry the rear wheel during their movement caused by the jolts of the bicycle advancing on the ground, and a resumption of the forces on the seat tube 12.

Significantly, the shrouds 22, respectively 23, are articulated in rotation with respect to the base tubes 20, respectively 21, around pivot axes 35 and 36 said rear pivots placed on the extension of the tubes base 20 and 21 when approaching the bores 33 and 34 for receiving the rear wheel axle, at a distance of the order of 9/10 of the total length between the bottom bracket 13 and the axle rear wheel defined by bores 33, 34. Thus, approximately 1/10 ^th of the total length of the base of the bicycle is not carried by the base tube 20 or 21, but by an additional base section carried by the corresponding guy 22 or 23, and denoted attached section 201.

The combination of the pivot connections defined by the main pivot axes 31 on the one hand and rear pivot 35 and 36 on the other hand defines a suspension with virtual pivot point, since the rear wheel is caused to follow a movement , vis-à-vis the front triangle of frame 1 which is not a rotational movement around a physical pivot defined by a material axis, but an instantaneous rotational movement around a pivot point defined by geometry of the frame and axes 31, 35 and 36 and which may, moreover, not be fixed with respect to the front triangle over time, fully justifying the qualifier "virtual".

In Figure 2, there is shown the frame 1 and the battery 2 being extracted from inside the bottom body tube 11 by the underside thereof. The battery 2 essentially has the shape of an elongated rectangular parallelepiped. It can be seen that the lower end of the battery 2 is pressed into the lower end of the internal housing of the bottom body tube 11, and that its upper part is gradually extracted from the housing by pivoting. Conversely, it is possible to introduce the battery 2 by placing its lower end at the bottom of the housing of the bottom body tube 11 and then introducing the upper part into the upper part of the housing by a reverse pivoting movement. .

It is specified that this removable battery 2 but integrated into the frame participates in the rigidity thereof. The tilting movement to remove the battery 2 is particularly practical in use. The presence of the opening of the battery housing towards the bottom of the lower body tube 11 allows the placement of the damper 32 fixed on the upper part of the lower body tube 11.

The profile of the bottom body tube 11 perfectly accommodates the trunk of the battery 2, so that it is visually coincident with the frame, while contributing to its rigidity, and being perfectly anchored, so as to do not move at all even in the face of tremors and shocks to which an mountain bike is subjected. The electrical contacts are also very precisely adjusted.

In Figure 3, the head tube 14 is shown, with visible also in the view, the battery 2 and the bottom body tube 11. A ring 3 of annular geometry, along the axis of the head tube 14, cylindrical of revolution, is present as an extension of the bottom body tube 11 against the circumference of the mouth thereof, extending it by 2 cm. It is fixed in the head tube 14 by tight insertion of a narrower diameter section (not shown) of the ring 3 in the tube. The ring 3 is then taken in pincers between the fork (not shown) and the tube, with the interposition of the lower cup of the headset, in which is housed a ball bearing. It is specified that the lower cup of the headset is force-scanned in the ring 3, and that the upper cup of the headset is placed above the head tube 14, force-scanned in the mouth thereof. , and accommodating a ball bearing. The headset allows rotation and maintenance of the fork steerer in the steering tube.

The ring 3 when installed as in Figure 3 raises the handlebars relative to the fork compared to mounting the fork on the frame without the ring 3, as shown in Figure 4. This compensates for the 27.5 ”lower wheel height with which ring 3 is intended to be used. Conversely, when fitting a 29 "wheel, the ring is removed as in Figure 4, because the fork is then higher, and there is no need to raise it.

In Figures 5 to 9, the parts used to form the pivot axis 35 or the pivot axis 36 are presented. There are 4 of them, including a screw 101, and a complementary threaded nut 104 mounted tightly on the threaded rod of the screw 101. The surfaces of the attached section 201 of the guy 22 or 23 are also presented with which these parts interact. Figure 5 is a sectional view in a plane parallel to the axis of the screw 101.

On the rod of the screw 101, are also mounted, starting from the head of the screw, a ball bearing 102 and a spacer 103, both comprising a smooth cylindrical bore, through which is inserted the screw rod 101.

These two parts, like the head of the screw and the nut 104, each occupy along the axis of the screw a section extending between two parallel planes of which they do not protrude and by which they press on a neighboring surface.

The ball bearing 102 has the outer geometry of a cylinder of revolution, and the spacer 103 which comprises a smooth bore in which the screw is introduced, is formed of two sections which follow one another along the axis of the screw 101: a cylindrical section of revolution centered around the screw, placed in contact with the ball bearing 102 and an oblong section extending in the plane perpendicular to the axis, offset from the axis of the screw, placed opposite the nut 104. The smooth bore is placed on the long axis of the oblong shape.

The nut 104 also has an oblong outline in the plane perpendicular to the axis of the screw, oriented, for mounting purposes, like the oblong section of the spacer 103. The threaded bore of the nut in which the screw is introduced is off-center with respect to the barycenter of the part, and is placed on the long axis of the oblong shape.

In FIGS. 6 and 7, the recesses R1 and R2 of the internal surfaces SI and external SE of the attached section 201 of the stay 22 or 23 are shown in which the spacer 103 and the nut 104 are inserted, on both sides. on the other side of the guy, as shown in Figure 5.

The attached section 201 is a solid volume of aluminum (or other material), flattened along a plane parallel to the median vertical plane of the bicycle, and traversed transversely by a bore AL of oblong contours in said plane and into which is introduced the screw 101, with several possibilities of positioning, the oblong bore being too wide for the screw.

R1 and R2 recesses on both sides of the attached section 201 have respective oblong edges, and the through bore which connects them, also oblong as already mentioned, is of narrower dimensions (but homothetic), because it is defined by a recessed peripheral recess D2 also defining two bearing surfaces for the spacer 103 and the nut 104 inserted in the associated recesses R1 and R2 on either side of the attached section 201.

Thus, it can be seen in FIG. 5 that

- the underside of the head of the screw 101 rests on one of the faces of the ball bearing 102,

the other face of the ball bearing 102 rests on one of the faces of the spacer 103, in this case its face having a symmetry of revolution, as well as on a circular recess D1 of the bore of the tube base 20 or 21 in which the ball bearing 102 is introduced from outside the base tube assembly 20, 21 - guy 22, 23, and from the space between the two bases and the two guys (denoted internal space El ),

- the second face of the spacer 103, of oblong shape, rests on the oblong recess D2 against which the spacer 103 is pressed from inside the base-stay assembly (between the base tube 20, 21 and the stay 22 , 23 correspondent),

- and one of the faces of the nut 104 rests on the other side of the oblong recess D2 against which it is pressed while being approached from the outside of the base-shroud assembly, and from the outside of the bicycle ( noted external space EE).

The faces of the spacer 103 and the nut 104 resting on the oblong recess D2 are both chamfered at the periphery to facilitate the introduction of these two parts into the corresponding recess, namely recesses R1 and R2, respectively.

The recesses R1 and R2 have a regular oblong shape, so that it is possible to place the spacer 103 in the recess R1 in two ways, resulting from each other by a movement of symmetry relative to the plane P (represented in FIG. 5), median plane of the nut 104 perpendicular to the long axis of the oblong shapes and also place the nut 104 in the recess R2 also in two ways, resulting from each other by the same movement of symmetry with respect to the plane P.

Thus, there are four ways of positioning the couple of spacer 103 and nut 104, but two are inoperative because they lead to position the bores of these two parts offset relative to each other, while it is necessary to align to be able to insert screw 101.

If the spacer 103 and the nut 104, with their aligned bores, are returned (both) in the movement of symmetry relative to the plane P, the screw 101 can still be introduced through the attached section 201 and the latter screwed to the corresponding base tube 20 or 21.

The two ways of positioning the screw 101 have the effect with respect to each other of modifying the distance Δ (visible in FIG. 5) between a reference dimension CR of the base tube 20, 21 and the end of the attached section 201. The reference dimension CR is represented as the end of the part of the base tube 20, 21 wide and hollow and having a structural role on the major part of the tube, before its flattened extension in which the bore for the ball bearing 102 is formed.

These features are observed in Figures 8 and 9 where we find the screw 101 (whose head and threaded rod are visible, the head carrying a socket for a hexagon wrench), the ball bearing 102, the spacer 103 and the nut 104. The peripheral chamfers of the spacer 103, on its oblong surface opposite the annular surface, and of the nut 104 on one of its faces are more visible in FIG. 8 We also observe in Figure 9 on the spacer 103, between its two sections, a fillet connecting the annular surface to the recessed surface surrounding it on half of its circumference, offset along the axis of the bore. These chamfers and this fillet are also visible in section in Figure 5.

Figures 10 and 11 show the two ways of mounting a guy 22 or 23 and the base tube 20 or 21 corresponding. Depending on the orientation in which the nut 104 and the spacer 103 have been inserted in the associated recess, the rear wheel axis defined by the bores 33, 34 is more or less distant from the main pivot axis 31, shortening or lengthening the useful length of the base tubes 20, 21. In the assembly of FIG. 10, the rod of the screw 101 is closer to the bores 33, 34 than in the assembly of FIG. 11, and the distance Δ 'between the end of the attached section 201 of the shroud 22, 23 and the reference dimension CR is shorter than the corresponding distance Δ observed in the assembly of FIGS. 5 and 11.

Alternatively, the oblong recesses could be made on the base tube 20, 21, and the oblong pieces could be inserted in this base tube 20, 21 to define the two assemblies.

According to another alternative, the oblong shapes could be replaced by any non-regular shape around the axis of the screw, which can be positioned with two distinct angular indexings around the axis imposing two different longitudinal offsets of the base tube 20, 21 and the related section 101.

Thanks to these principles, it is easy, from an ATV equipped with wheels of a certain diameter, for example 27.5 inches, to disassemble the wheels,

- disassemble the fork and stem, disassemble the lower part of the headset, remove the ring 3, insert the lower part of the headset directly into the head tube,

- dismantle the rear axes 35, 36 and modify the orientation of the oblong parts 103 and 104 so as to lengthen the dimension Δ,

- reassemble the rear axles 35 and 36, reassemble the stem and the fork with the ring 3, and place wider wheels, for example 29 inches.

Conversely, from 29 inch wheels, by dismantling the elements and reassembling them by adding the ring 3 and shortening the dimension Δ, we can replace the 27.5 inch wheels.

These modifications can be carried out quickly between two races.

It is also possible to remove the ring 3, put a 29 inch wheel at the front, 15 and shorten the dimension Δ and put a 27.5 inch wheel at the rear.

These assemblies apply as much to an electric mountain bike as to a non-electric mountain bike.

Claims (8)

1. bicycle frame (1) with rear wheel suspension comprising a base in two sections (201, 202) articulated to each other by a horizontal pivot axis (35, 36, 101) to define a geometry of suspension with virtual pivot point, characterized in that one of the two sections (201, 202) has a recess (R1, R2) adjusted to receive a body (103, 104) fitted to the axis, the recess (R1, R2) and the body being shaped so that the axis (101) can be placed at two different ribs (Δ, Δ ') of the section of the base carrying the flushing (R1, R2) by modifying the angular indexing of said body (103, 104) with respect to the axis (101) during reassembly of said axis (101). 2. Bicycle frame according to claim 1, characterized in that the recess (R1, R2) is oblong with a main axis locally parallel to the axis of the base. 3. Bicycle frame according to claim 1 or claim 2, characterized in that the pivot axis (35, 36, 101) is formed by a screw-nut system (101, 104), and that the nut ( 104) is shaped to constitute such a body fitted to the axis which can be placed in two different orientations in such a recess (R2) then placed on one of the external faces (SE) of the sections (201,202). 4. Bicycle frame according to one of claims 1 to 3, characterized in that it comprises a part (103) to be placed fitted on the axis and between the two sections (201, 202), shaped to constitute such a body (103) fitted to the axis which can be placed in two different orientations in such a recess (R1) then placed on one of the internal faces (SI) of the sections (201,202). 5. Bicycle frame according to one of claims 1 to 4, characterized in that it further comprises a removable spacer (3) to define two possible heights of the fork with respect to the handlebars. 6. Bicycle frame according to one of claims 1 to 5, characterized in that the rear wheel shock absorber (32) is articulated at its ends respectively to the oblique tube (11) and the shrouds (22, 23) of the frame , the shrouds being articulated to the seat tube (12) by links (24, 25). 7. Bicycle frame according to one of claims 1 to 6, characterized in that the oblique tube (11) comprises a battery housing (2) for electric bicycle, with access to the battery on the lower side of the oblique tube (11 ). 8. Mountain bike equipped with a frame according to one of claims 1 to 7.