ES2265723A1 - Rear suspension for bicycle has shock absorber having upper and lower laminas that connect upper and lower parts of tubular base to pedal block - Google Patents

Abstract

The suspension has an articulated quadrilateral comprised of first and second connecting rods connected through pivots to braces connected to a tubular base that is connected to a pedal block. A shock absorber on the articulated quadrilateral has an upper lamina comprised of a deformable material which connects the upper part of the tubular base to the pedal block. A lower lamina also comprised of a deformable material connects the lower part of the tubular base to the pedal block.

Description

Rear suspension for bicycle.

Systems are known to achieve suspensions rear bicycles consisting of a frame, a articulated quadrilateral joined by its ends to the frame, a base tubular that joins the anchor of the rear wheel axle to the frame. On the other hand, this rear wheel axle anchor is attached by means of a strap to a tilting piece that transmits the terrain undulations, and a shock absorber that joins the frame with the tilting piece to cushion said transmission.

We cite as examples the Patents W00187697-A and US5899480 among others.

But known suspensions are not suitable for too hard, too soft, excessively heavy, and the  user wants a rear suspension that offers behavior Optimum with the minimum weight.

The applicant has studied the precise location of the junction points of the articulated quadrilateral to the frame of the bicycle, and especially the replacement of the main turning axis and their corresponding bearings for a deformation structure controlled, with consequent weight savings.

The applicant has studied the suspensions rear bicycles and consider the capacity of deformation of composite materials, suppose a opportunity to develop these new concepts.

To this end, a deformable structure of composite bases, for example fiber carbon preimpregnated in resin specifically arranged as well as ways that tend to locate the deformation in the area Specifies that the applicant after the corresponding tests considered suitable for their purposes.

The present invention advocates a suspension rear for bicycles consisting of an articulated quadrilateral joined by its ends to the seat tube, consisting of articulated quadrilateral of first connecting rods pivotally to second connecting rods that are attached to braces which in turn join a tubular base that joins the block of bottom bracket, and having a shock absorber performance on the articulated quadrilateral, which is characterized because it consists of:

a) an elastically deformable top sheet, of composite material that joins the upper part of the tubular base with the bottom bracket block, and

b) an elastically deformable bottom sheet, of composite material that joins the bottom with the tubular base with the bottom bracket block.

It is also characterized because the sheets upper and lower are "U" shaped by placing each other with the opposite concavity forming a maximum sine deformation.

It is also characterized because the top sheet It presents greater resistance to bending than the bottom sheet.

It is also characterized because the sine of maximum deformation is arranged at a distance from the bottom bracket axis of approximately 1/6 of the distance between the bottom bracket and the Rear wheel axle: d_ {1} \ backsimeq 1/6 d.

It is also characterized in that the shock absorber is joins the armchair tube and its stem to a joint shaft of the first cranks with the second cranks being vertical the trajectory of said stem.

It is also characterized because the tubular base form with the rod fully extended a negative angle and with The fully compressed stem forms a positive angle.

The area in which all of the the flexion is composed of two sheets (top to bottom). These have an inverted double "U" shape, so that There is a point at which the distance between them is very small. Bearing in mind that the moment of inertia is proportional to the square of the distance between plates, the great is evident reduction in the area of minimum distance between plates. Is where we can consider maximum flexion occurs.

The solidarity nature of the deformable structure and the tubular base (the 2 tubes) that They will work in unison. In this way the flex zone is found between the union with the aluminum frame and the beginning of the tubular bases. Therefore, there will be no possibility that Each tubular base flexes independently. In this way, it achieves greater rigidity of the whole and less overexertion of adjacent pieces since the mechanism will maintain alignment between axes required for proper operation, avoiding breakage and possible slacks

In this way the deformable structure object of the invention can be considered a "monoflexion" system of broadband, since there is only one flexion point but with a width greater than the existing ones. Therefore the greatest rigidity lateral and precision of this deformable structure involve some notable advantages both in quality of use and longevity.

The two upper and lower plates facing each other allow superior and differentiated deformations. This is due to that during compression-extension processes of the plates, there will be a slight approach-distance between them. The nature so clearly differentiated from the top plate e Bottom allow independent, specific and simple laminate of the upper plate and the lower plate, which gives the I invent greater versatility and ease in its manufacture.

To better understand the purpose of this invention, a preferred form of practical realization, susceptible to accessory changes that do not distort its foundation.

Figure 1 is a perspective of a picture of bicycle that incorporates the rear suspension object of the invention.

Figure 2 is an approximate side view of Figure 1

Figures 3a and 3b are plan views and Bitubular base lateral and deformable structure.

Figure 4 is a perspective view of the deformable structure with its connection to the rest of the bicycle.

Figure 5 is a side view of the suspension object of the invention with the shock absorber fully extended.

Figure 6 is a side view of the suspension object of the invention with the shock absorber fully compressed.

Figure 7 is a coordinate representation of the rear wheel path with the suspension subject to invention.

Figure 8 is a coordinate presentation of the rear axle-bottom bracket distance depending on the rear wheel travel.

Figure 9 is a coordinate representation of the damper ratio (continuous line) and of the overall ratio with the suspension object of the invention (broken line) depending on the rear wheel travel.

An example of practical, non-limiting embodiment of the present invention.

In figures 1 and 2 it can be seen in a bicycle, the front triangle (1) with the saddle tube (2) and rear suspension (3) that joins the front triangle-frame (1).

A rear suspension (3) is already known that it consists of an articulated quadrilateral joined by its ends to the box (1). The articulated quadrilateral consists of first connecting rods (4), second connecting rods (5), braces (6_ {1}), (6_ {2}) and a tubular base (7) formed by two tubes (8_ {1}), (8_ {2}) which are attached to the bottom bracket block (9) of the frame (1).

A pneumatic shock absorber (10) joins the saddle tube (2) and pivot shaft (11) between the first (4) and second (5) cranks.

The basis of the invention lies in joining the two tubes (8_ {1}), (8_ {2}) from the tubular base (7) to the shaft block bottom bracket (9) by means of a single common deformable structure for both tubes (8_ {1}), (8_ {2}).

Said deformable structure is constituted by a top sheet (12) formed of layers of composite material, elastically deformable that joins the upper part of the tubes (8_ {1}), (8_ {2}) from the tubular base (7) to the shaft block bottom bracket (9) and a bottom sheet (13) formed by layers of composite, elastically deformable material that joins the part bottom of the tubes (8_1), (8_2) of the tubular base to bottom bracket block (9).

If desired, the tubes can be closed (8_ {1}), (8_ {2}) with internal walls (14) to prevent entrance-accumulation of water or land.

The layers of composite material can be of any of the known, for example T 700 S carbon fibers of different lengths and orientations, glass fibers, kevlar, etc. etc., as well as the polymerizable resin, for example nylon.

Preferably the upper and lower sheets (12), (13) are "U" shaped by placing each other with the opposite concavity, leaving a small separation in the breast (15) (Δ) between them and being in said sine (15) where it occurs maximum flexion

The top sheet (12) has greater strength at flexion than the bottom sheet (13) which is achieved using different materials and / or different thicknesses and / or fiber arrangement, etc.

       \ newpage
    

Example

one

According to the data indicated, the largest  resistance of the bending laminate according to Module E 22 which is located perpendicular to the longitudinal axis of the picture. Module E_ {f1} which marks the flexibility in the direction vertical of the bases is about 3 times lower, as can be seen with respect to the module E_ {f2}. This way you get initially part of the objective sought.

If we add geometry to this construction specific developed, defined by an approach between plates which becomes 5 mm at its minimum point from about 30 mm from separation in the area of gluing to the bottom bracket block (9), We get totally directional properties. That is one high deformability in the vertical direction, maintaining the rigidity required both lateral flexion and torsion.

Eventually you could enter different internal elements such as foams, foams, air chambers, etc. In order to reinforce the structure, absorb small vibrations or isolate the internal structure of external agents.

The arrangement is also the subject of the invention. relative of the elements that come into play in the suspension rear

With the opposite presence of the plates upper (12) and lower (13) deformation can be achieved angular that is combined with the action of the shock absorber (10).

The reference length (L) being the distance between the bottom bracket (0) and the anchor (A) to the frame of the shock absorber (10), the sine (15) of the upper blades (12) and lower (13) will be arranged approximately at a distance (d_ {1}): d_ {1} \ backsimeq 0'15 L of the bottom bracket (0).

The distance (d) between the bottom bracket axis (0) and the axle (T) of the rear wheel is approximately 0.9 L, so d_ {1} \ backsimeq 1/6 d.

Preferably the rod (16) of the shock absorber (10) that joins the axis (11) of connection of the first connecting rods (4) with the second cranks (5) will have a quasi trajectory vertical.

With all this a suspension of Maximum performance

Example

(Figures 5 and 6)

The angular deformation that is obtained exceeds slightly 14 °, which will result in a movement vertical axis (T) of the rear wheel of 82 mm.

The position in which the shock absorber (10) is fully extended (figure 5) causes a deformation angle (α1) for the tubular base (7) in the opposite direction to the angle (α2) that occurs during compression maximum (figure 6). That is, so that the tubular base (7) is find in its natural position the shock absorber (10) must be compressed in 20% (6.4 mm) of your total stroke (32 mm).

The shock absorber (10) is not rotated with respect to its anchor (A). In addition the travel of the rod (16) of the shock absorber (10) coincides with its vertical displacement, specifically 32 mm.

The objective of using this configuration Specific resides in the following factors:

1. Distribute the deformation both ways (compression-extension) in such a way that the maximum deformation required of the sheets (12), (13) is less than which would correspond in case of bending in one direction only. From this way we can observe how the deformation of the sheets upper-lower (12), (13) cause a movement in the tubular base (7) which will be 17 mm "down" and 65 mm "upwards". It is therefore clear the need for a differentiated construction of the lower and upper part.

2. Once the user has arranged on the ideal compression bike for the type of use to which this System is intended, it is 20%. Therefore, with a correct Adjusting the air pressure of the shock absorber, the system will you will find in the natural position of the sheets (12), (13) with the user arranged on the bike on flat ground and without irregularities At this point the system will have a large capacity and smooth face to absorb potholes of considerable extent, but It can also be adapted to possible depressions (type of holes) extending those 17 mm, increasing the ride comfort.

3. The opposition that the upper plates e lower (12), (13) oppose the flexion added to the demultiplication of the force that opposes the shock absorber to compressed, give the system optimal progressivity.

4. The trajectory of the axis (T) of the rear wheel during compression is characterized by an arch, of so that the distance between the axle (T) of the rear wheel and axle bottom bracket (0) remains virtually unchanged (lower variation at 1%). Therefore there will be no contamination between the system suspension and chain shot by not varying the distance between both (the variation from 430.5 to 433 is considered negligible).

In figure 7 we observe the real trajectory which will describe the axle (T) of the rear wheel in its trajectory upward. On the X axis we have the horizontal distance from the axis front to rear, while on the Y axis we have the height relative of the axle (T) of the rear wheel with respect to the bottom bracket (0).

In figure 8 we observe the evolution (Y axis) of the distance between the axle (T) of the rear wheel and the axle bottom bracket (0) depending on travel (rear axle height (T) with respect to the bottom bracket (0)), determined on the X axis.

5. System progressivity comes determined by the gear ratio of the shock absorber and the opposition of the sheets (12), (13) to the deformation wing.

The ratio indicates the relationship between the route of the rear axle (T) and the rod travel (16) shock absorber, for each position of the damper stem.

According to figure 9 we can see that the ratio initially it is 2.3, which indicates that the forces on the axis of The rear wheel reaches the shock absorber multiplied by 2.3. According to the graph as the system is compressed this ratio increases, so that the forces on the shock absorber (10) they are even greater and therefore the sensations are of a softer cushion as compressed.

However, we must bear in mind that plates (12), (13) will oppose flexing proportional to the spin performed (Force = Cte. x Turn).

       \ newpage
    

During the first quarter, the plates (12), (13) tend to compress the shock absorber (10) until it reaches its initial position so the overall ratio in the first part It will be 2.5 approx. The sheets (12), (13) tend to make the softer system until it reaches its natural position, increasing the overall ratio of the system during the first tranche. One time exceeded the natural position (20% of the total route), they will tend to make the system harder by decreasing the overall ratio of the system.

In figure 9 we can see the slight tendency to increase the ratio (softening of the suspension) to as the system is compressed (continuous line). However, at add the opposition of the sheets (12), (13) to deform, we will obtain a linear behavior (dashed line).

Claims (6)

1. Rear suspension for bicycles, consisting of an articulated quadrilateral attached at its ends to the saddle tube (2), consisting of the articulated quadrilateral of first connecting rods (4) pivotally connected (11) to second connecting rods (5) they join braces (6_ {1}), (6_ {2}) which in turn are attached to a tubular base (7) that joins the bottom bracket block (9), and a shock absorber (10) is provided of action on the articulated quadrilateral, characterized in that it consists of: a) a deformable top sheet (12) elastically, of composite material that joins the upper part of the tubular base (7) with the bottom bracket block (9), and b) a deformable bottom sheet (13) elastically, of composite material that joins the bottom with the tubular base (7) with the bottom bracket block (9). 2. Rear suspension for bicycles, according to the preceding claim, characterized in that the upper (12) and lower (13) sheets have a "U" shape, positioning each other with the opposite concavity forming a breast (15) of maximum deformation. 3. Rear suspension for bicycle, according to claim 1, characterized in that the upper sheet (12) has greater flexural strength than the lower sheet (13). 4. Rear suspension for bicycles, according to claims 1 to 3, characterized in that the sine (15) of maximum deformation is arranged at a distance (d_ {1}) from the bottom bracket (0) of approximately 1/6 of the distance ( d) between the bottom bracket axle (0) and the axle (T) of the rear wheel: d_ {1} \ backsimeq 1/6 d. 5. Rear suspension for bicycles, according to claim 1, characterized in that the shock absorber (10) is attached to the armchair tube (2) and its rod (16) to a shaft (11) connecting the first connecting rods (4) with the second cranks (5) the trajectory of said rod (16) being vertical. 6. Rear suspension for bicycle, according to claim 5, characterized in that the tubular base (7) forms with the rod (16) fully extended a negative angle (α1) and with the rod (16) fully compressed forms an angle (α2) positive.