Patent Application
20140035256
The invention is encompassed in the field of full suspensions, for example, for bicycles, although it is also applicable to similar vehicles, for example, a motorcycle.
The purpose of both the front and rear bicycle suspensions is to absorb terrain obstacles and to increase stability in rough terrain. Since the obstacles affect the wheels of the bicycle, historically each of the two degrees of freedom corresponding to a full suspension bicycle have been associated with each of the wheels, such that the front suspension is responsible for damping the impacts on the front wheel, whereas the rear suspension dampens the impacts on the rear wheel. The suspensions virtually serve to replace the rigid link between the wheels of the bicycle and the frame thereof (to which the saddle, the pedals, and the handlebar is attached) with an elastic link, such that the frame of the bicycle is provided with two degrees of freedom with respect to the axles of the wheels.
However, suspensions do not only act against uneven terrain: the forces of the cyclist, such as the forces generated by the cyclist upon pedaling or the inertia effects of the cyclist him/herself upon speeding up or braking, also activate the suspensions, which is dangerous. Pedaling is a periodic movement in which a mainly vertical oscillating force is exerted which in turn generates a simultaneous bobbing movement in both suspensions. During this movement the damper of the suspensions dissipates part of the energy generated in pedaling, which reduces pedaling efficiency, while at the same time creates an unpleasant bobbing (movement in vertical direction) of the bicycle, further reducing the pedaling efficiency. On the other hand, speeding up and slowing down the bicycle entails a pitching movement on the suspensions, entailing the compression of one of the suspensions and the extension of the other. This results in part of the force being absorbed by the suspensions while speeding up, and further causes an uncomfortable movement for the cyclist while speeding up, whereby the bicycle reactivity is worsened. Similarly, pitching involving the verticalization of the angles and the reduction of the travel available in the fork occurs due to the suspensions upon braking, negatively affecting the stability of the bicycle going downhill.
In the recent years a clear trend towards increasing the suspension travel in each of the different categories of bicycles has been observed, whereby the irregularity absorbing capacity has increased considerably, but they also increase the unwanted movements, which would make the use of the bicycle itself in several conditions uncomfortable. The new technologies developed by suspension manufacturers (pedaling platforms and differentiated compression controls at high and low speed) and frame manufacturers (suspension systems in which the interaction with the transmission and braking is made use of) for controlling unwanted movements has enabled increasing suspension travels, the evolution of these technologies being one of the main fields in the continuous improvement of bicycles by the manufacturers.
For example, different rear suspension systems designed based on an interaction between the transmission and the suspension are known in the state of the art, which by making use of the tension originated in the chain cause a loss of suspension sensitivity and the blocking of said suspension, whereby the pedaling oscillations drop; however, the impact absorbing capacity also drops at the same time. Designs of this type are disclosed, for example, in documents U.S. Pat. No. 5,553,881, U.S. Pat. No. 5,628,524, U.S. Pat. No. 6,206,397, WO-A-98/49046 and U.S. Pat. No. 7,128,329.
Blocking for the units acting as the connecting link is a common solution to prevent oscillations upon pedaling. Therefore, the bicycle neither rotates nor reacts with respect to the bumps on the terrain. In the state of the art there are also partial blockings commonly known as pedaling platforms, in which the suspensions are blocked for forces less than a certain threshold, associated with the pedaling forces, and are unblocked for greater forces associated with uneven terrain. Samples of such pedaling platforms are, for example, the solutions disclosed in U.S. Pat. No. 5,190,126 and U.S. Pat. No. 7,163,222. Another partial blocking system is that of the inertia valves, disclosed, for example, in U.S. Pat. No. 7,273,137, in which the inertia of an inner mass unblocks the suspension as the wheel is lifted when traveling over a bump.
On the other hand, US-A-2003/132602 discloses a system in which an electronic sensor detects the movement of the front suspension with respect to an obstacle and regulates the rear suspension in anticipation of the approaching obstacle.
Document U.S. Pat. No. 7,017,928 discloses a suspension system for full suspension bicycles in which the front unit and the rear unit have their own degrees of freedom but they are related to one another by means of a hydraulic or pneumatic tube. The interaction between the front and rear units is used for adjusting the different heights of saddle, front suspensions and rear suspensions, but said interaction between the units is not active during the suspension operation, neither being active in the adsorption of bumps nor upon pedaling.
Suspension systems with hydraulic connections are known in the field of motor vehicles. Examples of this type of systems are disclosed in WO-A-98/18641 and in EP-A-1426212 (corresponding to ES-A-2223205).
On the other hand, WO-A-97/29007 describes a system in which, to prevent a series of drawbacks of the bicycles of the state of the art, a connection has been provided between the front suspension and the rear suspension such that a load or movement in one of the suspensions affects the other. In one embodiment the suspensions are hydraulic cylinders and the front and rear suspensions are connected by means of a connection of two of the cylinders. Therefore, if actuating a suspension causes the ejection of the hydraulic fluid from a chamber of a cylinder of said suspension, a chamber of a hydraulic cylinder of the other suspension is filled. Both suspensions are thus hydraulically coupled. The idea seems to be achieving that whatever occurs with one of the suspensions affects the behavior of the other. WO-A-97/29007 also suggests that the coupling between the two suspensions is variable, something which can be achieved with a valve in the hydraulic system.
The absorption part will determine the movement of the suspension and the damper will determine at what speed said movement occurs with respect to a force on the suspension, even though if the force is not maintained during the necessary time the complete movement will not be achieved. It is therefore possible to control the activity of the suspensions with damping. A low damping slightly controls the suspensions, whereby the suspensions move quickly with a long travel (convenient for when the movement of the suspensions is desirable), whereas a high damping greatly controls the suspensions, whereby the suspensions move slowly with a short travel (convenient for when the movement of the suspensions is not desirable).
The main differences between a low-end fork and a high-end fork correspond to their damping systems. In high-end forks, in addition to the main hole with regulable passage 1111 (see
In general, force sensitive hole systems can only be deformed towards one side, therefore the flow in opposite direction is always blocked. Therefore two force sensitive holes are usually provided so that each regulates the high speed flow in each direction 1112 and 1113 (see
The operation of a conventional rear damper can be very similar to that of the fork, except that instead of having the absorption elements and damper in parallel in the respective legs they are usually concentrically arranged, as is schematically shown in
All this is conventional and describing it in more detail is not considered necessary.
Conventional full suspension bicycles have two degrees of freedom, one per each axle and suspension element. In other words, each suspension element works independently on a single degree of freedom, as will be explain below with reference to
When the cyclist is not mounted on the bicycle the front and rear units are in a maximum extension state or a minimum compression state X0, Y0; in
In
As has been mentioned above, the quality of suspensions depends mainly on the qualities of the hydraulic part and the possible regulations (compression at low speed, compression at high speed, rebound at low speed, rebound at high speed) both over the flow rates Q1, Q3, and Q5 in the unit of holes 1002 and 2002, and over the flow rates Q2, Q4, and Q6 which affect the compensation chamber and which must traverse the units of holes 1005 and 2005.
The movement of the suspensions is desirable in impact absorption so that the energy of the impact or the irregularity of the terrain do not reach the cyclist, or at least reach at a reduced level. Therefore less restrictive regulations of the compression, mainly high speed regulations (impacts) are usually desirable to facilitate the action of the suspensions. This low damping entails that little of the energy transmitted to the suspensions is dissipated during the compression in the form of heat and that most of it accumulates in the absorption element. This absorbed energy is that which causes the subsequent extension to the initial position. If the restriction was also low during extension most of the initial energy would be returned after the compression in the form of a bounce of the wheel with loss of effectiveness and control. To prevent this it is advisable to dampen all the energy absorbed during extension, for which a greater rebound restriction is required. An excessive restriction can also be dangerous due to the fact that the extension would be very slow and could thereby lead to the case where the fork is not entirely extended and does not have its entire capacity upon reaching the following impact.
The movement of the suspensions is not desirable while pedaling and braking. In the first case it absorbs part of the energy from pedaling and the bobbing caused is uncomfortable, and in the second case it causes a change in the geometry, making the angles vertical, which results in a less stable bicycle. Both unwanted movements are low frequency oscillations in comparison with the movement in impact absorption. Therefore, to prevent the action of the suspensions in these conditions, restrictive compression regulations, mainly low speed regulations are usually desirable. This greater damping entails slower movements, whereby with respect to rotating or punctual forces (such as pedaling and braking respectively), the force ceases before the suspension reaches its entire travel, according to the elastic element.
Therefore the conflict in adjusting suspensions is mainly in the compression; the compression being low for impact absorption and high for pedaling or speeding up (including braking) is of interest. The trend that tends to be followed is to heavily restrict (even blocking) compression at low speed to reduce the unwanted movements and then partially restrict compression at high speed so that it provides a sufficient irregularity absorption which does not involve too much movement, for example, upon pedaling or braking. Sometimes this configuration tends to be called “pedaling platform”. In a simplified manner it is understood that in this configuration all the forces below a threshold do not cause movement whereas the forces greater than the threshold cause movement. Although this concept serves to at least partially limit the bobbing of the bicycle upon pedaling, while at the same time allow damping strong impacts, the problem is a certain conflict between the impact absorption and the reduction of bobbing, and often, due to the need of reaching a compromise, the bicycle tended to produce a bobbing movement when it is pedaled rigorously, while at the same time not absorbing small impacts well.
WO-A-2011/138469 describes a suspension system for a bicycle comprising a bicycle frame, a front wheel, and a rear wheel, the suspension system comprising:
a front unit configured to be interposed between the bicycle frame and said front wheel; and
a rear unit configured to be interposed between the bicycle frame and said rear wheel.
The front unit comprises at least one first front hydraulic chamber and a second front hydraulic chamber, and the rear unit comprises at least one first rear hydraulic chamber and a second rear hydraulic chamber. The system comprises a first tube attaching said first front hydraulic chamber with said first rear hydraulic chamber such that there is a hydraulic connection connecting said first front hydraulic chamber and said first rear hydraulic chamber (i.e., such that a hydraulic fluid outlet from one of the chambers can correspond to a hydraulic fluid inlet in the other chamber, and vice-versa), and a second tube attaching said second front hydraulic chamber and said second rear hydraulic chamber such that there is a hydraulic connection connecting said second front hydraulic chamber and said second rear hydraulic chamber.
The system described in WO-A-2011/138469 is configured such that a compression of the front unit produces, through the first tube, when it is in an open state, a hydraulic force on the rear unit for extending the rear unit, and, through the second tube, when it is in an open state, a hydraulic force on the rear unit for compressing the rear unit (and vice-versa).
It can thus be stated that the first tube is associated with a pitching movement since the compression of one of the units contributes to the extension of the other, and vice-versa. It also can be stated that the second tube is associated with one degree of freedom of bobbing since it contributes to a simultaneous compression—or extension of the front and rear units.
It is thus possible to determine the behavior of the suspension and, particularly, the degree of blocking of the bobbing and pitching movement respectively, acting on the communication between the hydraulic chambers, i.e., on the tubes. The configuration thus described allows selectively blocking, and optionally gradually blocking, for example, the pitching and/or the bobbing with valves acting on the communication between the hydraulic cylinders of the front and rear units through the first tube and the second tube. This regulation of the hydraulic connections through the first tube and the second tube can be, for example, manual regulation—such that the cyclist him/herself can control it even while cycling- or more or less automatic regulation, for example, depending on the impacts suffered by the moving bicycle. It is thus possible to prevent the bobbing of the bicycle in the case of rigorous pedaling, while at the same time also allowing a suitable damping of small impacts in the front or rear wheel.
Although the system described in WO-A-2011/138469 can work satisfactorily, it may have some constructive limitations, where it may not be ideal at least in certain cases or where its incorporation in a more or less conventional bicycle may involve certain difficulties and/or require certain changes in the design. Therefore, it has been considered that providing an alternative system which also acts on the degrees of freedom for bobbing and pitching, but with a different configuration of elements which is preferably easily incorporated in conventional bicycles may be desirable.
A first aspect of the invention relates to a vehicle suspension system (for example, a bicycle, although it also can be applied to other vehicles, for example, a motorcycle) comprising a vehicle chassis (the chassis can be, for example, a frame, for example, a bicycle frame; it can be considered that the frame is not only made up of that which is traditionally considered as the “bicycle frame” itself, but also of the elements attached to this frame, such as the handlebar, the seat, etc., excluding the front and rear wheels), a front wheel, and a rear wheel, the suspension system comprising:
a front hydraulic cylinder configured to be interposed between the chassis and said front wheel; and
a rear hydraulic cylinder configured to be interposed between the chassis and said rear wheel.
Each of these hydraulic cylinders can comprise a cylinder and a piston or plunger which moves in the cylinder which can in turn contain a hydraulic fluid, such as, for example, oil; the plunger can be provided with a hole or with a unit of holes, for example, with a unit of high and low speed holes, as is common in the state of the art; for example, it can be a unit of holes such as that which has been described above in relation to
The suspension system further comprises a first hydraulic connection connecting the front hydraulic cylinder and the rear hydraulic cylinder, such that the hydraulic fluid can pass from the front hydraulic cylinder to the rear hydraulic cylinder through said first hydraulic connection (this first hydraulic connection can comprise, for example, one or several tubes in series and/or in parallel).
According to the invention the system additionally comprises
In other words, the change of volume of hydraulic fluid in one of said compensation chambers is proportional to the change of the volume of hydraulic fluid in the other compensation chamber, and with the same sign, i.e., if the volume of hydraulic fluid in one of said chambers increases, it also increases in the other, and the increase of the volume of hydraulic fluid in both chambers is the same or at least proportional to a coefficient depending on the design of the system. The same applies to the reduction of the volume of the hydraulic fluid in the chambers. It also can be stated that if the volume of the air—or gas, or other mean or elastic element—in one of the compensation chambers reduces or increases, the same occurs in the other in a proportional or substantially proportional manner. The change of the volume of the hydraulic fluid in a compensation chamber must not be understood as that the hydraulic fluid necessarily physically enters (or exits) into (from) a chamber with clearly defined physical limits, but rather an occurrence of the movement of an elastic means (such as, for example, of an airbag), with the subsequent change of the volume of the elastic mean caused by the pressure exerted by the hydraulic fluid directly or through some moveable element.
The suspension system further comprises
Each hydraulic connection can comprise one or more tubes and can include valves or other elements which allow limiting the flow of the hydraulic fluid through the connection in question. The sensitivity of the system towards different conditions can thus be adjusted and its response can be provided in the form of pitching and/or bobbing.
In other words and in a manner similar to that found in the system described in WO-A-2011/138469, the described configuration allows selectively blocking and optionally gradually blocking, for example, the pitching and/or the bobbing with valves acting on the communication between the hydraulic cylinders and the compensation chambers through the first, second and third hydraulic connections. This regulation of the hydraulic connections can be, for example, manual regulation—such that the user him/herself can control it even while cycling—or more or less automatic regulation, for example, depending on the impacts suffered by the moving vehicle (for example, a bicycle). It is thus possible to prevent the bobbing of the bicycle in the case of rigorous pedaling while at the same time also allowing a suitable damping of small impacts in the front or rear wheel.
On the other hand, its simple configuration which only requires two hydraulic cylinders, a front and another rear cylinder, allows an easy integration of the system in the basic structures of vehicles such as conventional bicycles (since they have a front hydraulic cylinder and another rear hydraulic cylinder). The compensation chambers can be designed in different shapes, including shapes that allow their integration in the front or rear suspension, for example, in the fork of a bicycle itself.
In some embodiments of the invention one of said first compensation chamber and second compensation chamber can be housed inside the other of said first compensation chamber and second compensation chamber. This configuration can be very compact and is particularly suitable for integrating the compensation chambers in a tubular structure, such as the fork of a bicycle or motorcycle. In some embodiments of the invention the cylinder of one of said compensation chambers can be attached to the piston or plunger of the other of said compensation chambers, such that the movement of said plunger entails the movement of said cylinder. This configuration can also be suitable to facilitate the integration of the compensation chambers in a substantially tubular structure.
In some embodiments of the invention said first compensation chamber and second compensation chamber can be concentrically arranged.
In some embodiments of the invention the first compensation chamber can comprise a first plunger and the second compensation chamber can comprise a second plunger, said first plunger and second plunger being, for example, mechanically attached to one another, such that the movement of one of said plungers entails the movement of the other of said plungers. The compensation chambers can, for example, be located in parallel (for example, as illustrated in
In some embodiments of the invention the first compensation chamber and the second compensation chamber can be integrated in a front fork of the vehicle. This solution can be very practical since it represents an easily integrated solution which is compatible with the conventional structures of, for example, bicycles.
In such system the second hydraulic connection can comprise at least one tube connecting the second compensation chamber with the rear hydraulic cylinder.
In some embodiments of the invention one of said compensation chambers can be integrated in the front hydraulic cylinder and/or one of said compensation chambers can be integrated in the rear hydraulic cylinder. It can, for example, be integrated such that a tube between the compensation chamber in question and the hydraulic cylinder in question is not necessary, both forming one and the same cylinder.
In some embodiments of the invention both compensation chambers can be integrated in a rear damper of the vehicle. In such system the second hydraulic connection can comprise at least one tube connecting the first compensation chamber with the front hydraulic cylinder.
In some embodiments of the invention the first compensation chamber and the second compensation chamber form a unit arranged outside a front fork of the vehicle and outside a rear suspension of the vehicle. A configuration in which the first compensation chamber is integrated in a fork of the vehicle and in which the second compensation chamber is integrated in a rear damper of the vehicle is also possible. The compensation chambers are associated with one another such that the change of volume of the hydraulic fluid in one of the chambers corresponds to a proportional change of volume of the hydraulic fluid in the other chamber, as has been described above. The chambers can, for example, include plungers attached by a mechanical mechanism.
In some embodiments of the invention the system further comprises a valve located in the first hydraulic connection and in another hydraulic connection, the valve being configured such that said valve controls the opening state of the other hydraulic connection depending on the difference between the pressure in a first part of the first hydraulic connection and a second part of said first hydraulic connection. In other words, the pressure difference between the front hydraulic cylinder and the rear hydraulic cylinder virtually determines the opening state of the other hydraulic connection, which can be the second or the third hydraulic connection; in fact, such valves can be inserted both in the second and in the third hydraulic connection.
In some embodiments of the invention the system further comprises a valve located in the first hydraulic connection and in another hydraulic connection, the valve being configured such that said valve controls the opening state of the first hydraulic connection depending on the difference between the pressure in a first part of the other hydraulic connection and a second part of said other hydraulic connection. In other words, the pressure difference between two parts of the other hydraulic connection, which can be the second or the third hydraulic connection, virtually determines the opening state of the first hydraulic connection. Therefore, the conditions in the degree of freedom of bobbing can regulate the behavior in the degree of freedom of pitching. The behavior of the suspension can be adapted to the users' preferences using several valves of this type.
In some embodiments of the invention said valve can be configured for adopting a closed state when said pressure difference is below a predetermined level and an open state when said pressure difference is above a predetermined level.
In some embodiments of the invention, said valve can be configured for adopting an open state with a degree of opening which increases with said pressure difference.
In some embodiments of the invention said valve can be configured such that it can adopt a closed state in which it prevents the passage of hydraulic fluid through one of the hydraulic connections when hydraulic fluid does not pass through another of the hydraulic connections.
In some embodiments of the invention the valve can comprise a moveable piston configured to enable adopting a blocking position in which it simultaneously blocks the flow of hydraulic fluid through the first hydraulic connection and the flow of hydraulic fluid through the other hydraulic connection, and configured to be able to be moved, by a predetermined pressure difference in the first hydraulic connection, to an unblocking position in which it allows the flow of hydraulic fluid both through the first hydraulic connection and through the other hydraulic connection. Said predetermined pressure difference can be established by means of an elastic element, preferably a spring, which presses the piston towards the blocking position. The valve can comprise a casing provided with at least one first hole, the piston having at least one second hole configured so that a hydraulic fluid can circulate through said second hole as said hydraulic fluid passes through the first hydraulic connection when the piston is in the unblocking position. The piston can further comprise at least a third hole through which a hydraulic fluid can circulate as said hydraulic fluid passes through the other hydraulic connection when the piston is in the unblocking position.
In some embodiments of the invention said other hydraulic connection can be the second hydraulic connection or the third hydraulic connection. Obviously, a valve can simultaneously open and close several hydraulic connections or tubes. For example, one and the same valve can be configured for opening both the second hydraulic connection and the third hydraulic connection depending on a pressure difference between two points associated with the first hydraulic connection.
In some embodiments of the invention said valve can be integrated in a front fork of the vehicle or in a rear damper of the vehicle. Logically, in addition to these valves, there can be more valves for achieving a versatile and optimized high and low speed regulation in several or all the degrees of freedom. In one embodiment of the invention more than one of these valves, for example, all the valves, can be integrated in the front fork. The valves are preferably arranged together to minimize the number of tubes attaching them. Integrating them in the fork or in the rear damper may be an interesting solution.
In some embodiments of the invention the system can comprise a valve located in an intake associated with the front hydraulic cylinder and in an intake associated with the rear hydraulic cylinder, the valve being configured such that said valve controls the opening state of the first hydraulic connection connecting the intake associated with the front hydraulic cylinder and the intake associated with the rear hydraulic cylinder depending on the sum of the pressure in the intake associated with the front hydraulic cylinder and the pressure in the intake associated with the rear hydraulic cylinder.
In some embodiments of the invention said valve can be configured for adopting a closed state when said sum of pressure is below a predetermined level and an open state when said sum of pressure is above a predetermined level.
In some embodiments of the invention said valve can be configured for adopting an open state with a degree of opening which increases with said sum of pressure.
In some embodiments of the invention said valve can be configured such that it can adopt a closed state in which it prevents the passage of hydraulic fluid through the first hydraulic connection connecting the intake associated with the front hydraulic cylinder and the intake associated with the rear hydraulic cylinder when hydraulic fluid does not pass between the intake associated with the front hydraulic cylinder and the first compensation chamber through the first hydraulic connection and/or between the intake associated with the rear hydraulic cylinder and the second compensation chamber through the second hydraulic connection.
Another aspect of the invention relates to a motorcycle or to a bicycle comprising a suspension system according to any of the preceding claims.
An advantage of the invention lies in the hydraulic control of the suspensions based on the degrees of freedom for bobbing and pitching.
The movement of the suspensions of the bicycle or the motorcycle while braking and speeding up can be greatly minimized by restricting the hydraulic connections of the degree of freedom of pitching, maintaining a good absorption capacity as a result of the fact that the hydraulic connections of the degree of freedom of bobbing are less restricted therefore the movement of the suspensions in this direction is made easier. This is of interest in bicycles, but primarily in motorcycles where the speeds and dynamics are greater.
The movement of the suspensions of the bicycle upon pedaling can be greatly minimized by restricting the hydraulic connections of the degree of freedom of bobbing maintaining a good absorption capacity as a result of the fact that the hydraulic connections of the degree of freedom of pitching are less restricted therefore the movement of the suspensions in this direction is made easier. This is of great interest in bicycles but not in motorcycles.
Due to the fact the application of the invention is more varied and complete in bicycles, the invention will be described with reference to embodiments based on bicycles but it should not be forgotten that the advantages described are also applicable to motorcycles, primarily in that relating to the control of the pitching.
To complement the description and for the purpose of aiding to better understand the features of the invention according to several preferred practical embodiments thereof, a unit of drawings is attached as an integral part of said description in which the following has been depicted with an illustrative and non-limiting character:
Furthermore, as observed in
There is also a second hydraulic connection 71 connecting the front hydraulic cylinder 4 and the first compensation chamber 7, and a third hydraulic connection 81 connecting the rear hydraulic cylinder 5 and the second compensation chamber 8. The connections have been illustrated in the form of tubes but other connections, for example, direct connections are also possible, which could be practical and possible in the cases in which one of the compensation chambers is integrated in a corresponding hydraulic cylinder.
The hydraulic fluid can thus pass:
There can be an elastic element (for example, air, another gas, and/or springs) in both compensation chambers exerting a pressure on the hydraulic fluid, as is conventional in the compensation chambers.
According to this embodiment of the invention the elastic element is common to both compensation chambers.
In some of the drawings illustrating the embodiments of the present invention the compression states of the hydraulic cylinders are indicated according to the two axles “x” (for the front hydraulic cylinder 4) and “y” (for the rear hydraulic cylinder 5). In resting state; in
Due to the first hydraulic connection and the particular ratio between the compensation chambers, a ratio is established between the compression and extension states of the hydraulic cylinders affecting the degrees of freedom of pitching and bobbing respectively, in a manner similar to that achieved with the system described in WO-A-2011/138469, but with a different structure which is advantageous at least in some aspects. It can be considered that the present invention is a type of hybrid between the conventional full suspension systems (as have been described above, with a front hydraulic cylinder and a rear hydraulic cylinder) and the system described in WO-A-2011/138469. Advantages similar to those provided by the system of WO-A-2011/138469 in terms of hydraulic control can be achieved with the present invention, but with the possibility of having a structure and an absorption operation similar to those of the conventional full suspension system.
As has been described, in addition to the two suspension elements (with at least one hydraulic cylinder per axle) there is a third connection unit connecting the other two, comprising the two compensation chambers 7 and 8. The two suspension elements can be similar to the conventional suspension elements but with interrelated compensation chambers, as has been described above. Therefore, the structural part of the suspension elements and the absorption part can be the same as the conventional full suspension system, such that the behavior during absorption can be controlled by the classic degrees of freedom. On the other hand, the compensation chambers are attached to one another such that only a joint bobbing movement of both suspension elements is possible. On the other hand, there is an additional connection connecting the two suspension elements such that the pitching movement of the bicycle is produced with the flow of oil from one element to another. Therefore, the hydraulic behavior is also controlled by the degrees of freedom of bobbing and pitching, entailing the advantages of the full suspension system of WO-A-2011/138469. This is an interesting aspect of the invention: The damper can be controlled according to the degrees of freedom for absorption (movements along axles) and/or with respect to the degrees of freedom for bobbing and pitching.
With reference to
In
Therefore, the hydraulic behavior is similar to that of the system described in WO-A-2011/138469: part of the oil flows from the front unit through the degree of freedom of bobbing and another part through the degree of freedom of pitching compressing the unit, whereas in the rear unit there is a flow of oil through the degree of freedom of bobbing and through the degree of freedom of pitching which compensate one another, without there being movement in the rear unit.
(The hydraulic operation tends to be expressed primarily by pressures and flow rates. From a strict view point,
The compensation chambers of
How the mechanical attachment (through a direct mechanical attachment 10) between the plungers 72 and 82 of the compensation chambers means that the movement of one of the plungers entails the movement of the other plunger can be observed in
How the first compensation chamber 7 is housed inside the second compensation chamber, and how the cylinder 73 of the first compensation chamber 7 is attached to the plunger 82 of the second compensation chamber 8 is observed in
How at least one of the chambers comprises an elastic element 74 (
On the other hand, the compensation chambers can be positioned in different places without varying the basic operation of the system, as shown in
In
In
In
In
Therefore any system combining
Therefore, similar to that described in WO-A-2011/138469, one or more valves can be incorporated to influence the behavior of the system according to the different degrees of freedom, for example, to block the degree of freedom of bobbing depending on the degree of freedom of pitching. A valve 9 the opening state of which depends on, for example, the pressure difference between the front hydraulic cylinder 4 and the rear hydraulic cylinder 5 can, for example, be incorporated in the second hydraulic connection 71 and/or in the third hydraulic connection 81. An example of such valve is observed in
All the pressure difference in the first hydraulic connection 6 (pressure in the intake 6a with respect to the pressure in the intake 6b) falls on the piston 91 through the holes 90b of the casing 90. When the force is greater than the preload of the spring 92 due to said pressure difference, the piston 91 moves compressing the spring 92. Thereby opening up a passage for the fluid of the first hydraulic connection 6, circulating from the intake 6a going through the hole 90b of the casing 90 and through the central hole 91b of the piston 91 to the intake 6b. Similarly, the movement of the piston towards its unblocking position enables the flow between the intakes 81a and 81b through the outer annular hole 91a of the piston 91 provided that there is a pressure difference between both intakes.
Starting from the sag or equilibrium state of
The pressure in the front hydraulic cylinder 4 increases with respect to a front impact and the pressure in the first compensation chamber 7 also increases due to the second hydraulic connection 71. The valve 9 being closed and therefore there not being any volume variations in the compensation chambers, the sum of the forces on the plungers 72 and 82 must be maintained, which entails the pressure in the second compensation chamber 8 to decrease in proportion to the increase of the pressure in the first compensation chamber 7. On the other hand in the absence of forces in the rear wheel, a pressure variation does not occur in the rear hydraulic cylinder 5. The pressure of the front hydraulic cylinder 4 is transmitted to the valve 9 through the first hydraulic connection 6 (through the intake 6a), the pressure of the second compensation chamber 8 is transmitted to the valve 9 through the third hydraulic connection 81 (through the intake 81a), and the pressure of the rear hydraulic cylinder 5 is transmitted to the valve 9 through the intakes 6b (corresponding to the first hydraulic connection) and 81b (corresponding to the third hydraulic connection). The pressure difference between the intakes 6a and 6b opens the valve 9 whereby the intake 6a is connected to the intake 6b and the intake 81a is connected to the intake 81b. Due to the pressure difference between the front hydraulic cylinder 4 and rear hydraulic cylinder 5, a flow rate Q2″ occurs according to
On the other hand, reaction forces are generated in both axles on pedaling, which increases the pressure both in the front hydraulic cylinder 4 and in the rear hydraulic cylinder 5. The pressure increase therewith entails pressure increase in the first compensation chamber 7 and pressure reduction in the second compensation chamber 8. All these pressures are transmitted to the valve 9 through the connections or intakes 6a, 6b, 81a and 81b. Due to the pressure increase both in the front hydraulic cylinder 4 and in the rear hydraulic cylinder 5, there is no pressure difference between the intakes 6a and 6b, or the pressure difference is not sufficient to overcome the preload of the spring 92, therefore the valve remains closed. Therefore, despite the pressure difference between the intakes 81a and 81b, the presence of the valve 9 blocks the flow rates which are shown in
Therefore, with this valve 9 which is called R1 in
On the other hand, the valve 9 can also be used to control the pitching while braking or speeding up according to the regulation R3 of
Similarly, with respect to speeding up, the force on the rear axle increases while it reduces by the same measure on the front axle. Therefore, the pressure in the front hydraulic cylinder 4 and in the first compensation chamber 7 drop and increase in the rear hydraulic cylinder 5 and in the second compensation chamber 8, therefore there is also no pressure difference between the intakes 81e and 81f, whereby the valve remains closed preventing the movement of the suspensions despite the pressure difference between the intakes 6e and 6f (this feature can be interesting for bicycles but, perhaps, particularly interesting for motorcycles).
However, in a front impact, the pressures of the front hydraulic cylinder 4 and the first compensation chamber 7 increase, the pressure in the second compensation chamber 8 drops, and the pressure in the rear hydraulic cylinder 5 remains unchanged. A pressure difference is thus generated between the connections 81e and 81f opening the valve R3 which causes a movement of the suspensions according to
In
Furthermore, the conventional hydraulic regulations (i.e., those which are already used in the state of the art) are also applicable in the piston of each suspension element; in
In addition to the configuration of
R1′: Regulation of high speed diving: when the pressure in the connection 6a′ exceeds the pressure in the connection 6b′ at least that corresponding to the preload of the valve R1′, the valve connecting the connection 6a′ with 6b′, 71a′ with 71b′ and 81a′ with 81b′ opens.
R2′: Regulation of high speed squatting: when the pressure in the connection 6d′ exceeds the pressure in the connection 6c′ at least that corresponding to the preload of the valve R2′, the valve connecting the connection 6c′ with 6d′, 71c′ with 71d′ and 81c′ with 81d′ opens.
R3′: Regulation of high speed downward bobbing: The pressure of the front hydraulic cylinder 4 and rear hydraulic cylinder 5 fall directly on the piston of the valve R3′ through the connections 41′ and 51′ each discharging at either side of the piston keeping the connections 41′ and 51′ separated from one another when the valve is closed. In other words, the oil of front hydraulic cylinder 4 enters at one side of the piston and the oil of the rear hydraulic cylinder 5 enters at the other side, and both oils press on the spring of the valve. The preload of the valve R3′ is preferably adjusted at a value compensating the pressures in initial sag state, thus the valve remains closed while the sum of the reactions of both axles is the same, which includes braking and speeding up in which the reactions of each axle vary but the sum thereof remains constant. When the pressure in one of the connections 41′ or 51′ increases more than the pressure drops in the other, the valve opens and communicates the connection 41′ with the connection 71e′, the connection 51′ with 81e′, and the connection 41′ with 51′ by means of the inner connection 6e′ which stops separating both sides due to the movement of the piston.
R4a′: Regulation of low speed diving: the flow rate of passage through the tube 6f′ from the front hydraulic cylinder 4 to the rear hydraulic cylinder 5 is adjusted. The one way valve of the tube 6f′ blocks any flow rate from the rear hydraulic cylinder 5 to the front hydraulic cylinder 4.
R4b′: Regulation of low speed squatting: the flow rate of passage through the tube 6g′ from the rear hydraulic cylinder 5 to the front hydraulic cylinder 4 is adjusted. The one way valve of the tube 6g′ blocks any flow rate from the front hydraulic cylinder 4 to the rear hydraulic cylinder 5.
R5a′ and R5b′: Regulations of low speed downward bobbing: they regulate the flow rate of passage from the front hydraulic cylinder 4 to the first compensation chamber 7 through the connection 71f′ and from the rear hydraulic cylinder 5 to the second compensation chamber 8 through the connection 81f. Due to the attachment between the compensation chambers 7 and 8, both regulations affect both flow rates since these flow rates are always related according to ratio ΔV1/ΔV2.
Besides these regulations, the connections 71g′ and 81g′ drive the flow rate of the upward bobbing from the first compensation chamber 7 to the front hydraulic cylinder 4 and from the second compensation chamber 8 to the rear hydraulic cylinder 5 through the one way valves. The upward bobbing of the suspensions is controlled by means of the classic rebound high and low speed regulations of each axle R6-R9.
In a preferred configuration for a better integration of the proposed system, the unit of valves (R, R′, . . . ) and the unit of compensation chambers (7, 8) are integrated inside the fork 1000, for example, inside the left bar of the fork after moving the spring 1008 to the right bar as shown in
In this text, the word “comprises” and variants thereof (such as “comprising”, etc.) must not be interpreted in an excluding manner, i.e., they do not exclude the possibility that what is described may include other elements, steps, etc.
On the other hand, the invention is not limited to the specific embodiments which have been described, but it also encompasses, for example, the variants which can be carried out by a person skilled in the art (for example, in terms of the choice of materials, dimensions, components, configuration, etc.), within what is inferred from the claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/ES2012/070085 | 2/9/2012 | WO | 00 | 10/16/2013 |
