IT201800009343A1 - DAMPING VALVE FOR PNEUMATIC SUSPENSION OF TRUCK TRAILERS - Google Patents

Description

DESCRIPTION

of the Industrial Invention entitled:

DAMPING VALVE FOR PNEUMATIC SUSPENSION OF TRUCK TRAILERS

DESCRIPTION

Technical field of application

The present invention is aimed at the mechanical / automotive sector and relates in detail to a damping valve for pneumatic suspension of trailers for trucks particularly suitable for use on light or heavy trucks, lorries, articulated lorries, lorries, trucks or trucks, tractors, campers, etc …

Pre-existing technique

The pneumatic suspension of a truck trailer is a set of elastic components through which the trailer is able to absorb and cushion the shocks caused by ground imperfections both under full load and empty conditions, and to guarantee stability as a result. reducing oscillations.

If the trailer loading surface were rigidly connected to the wheel axles, all wheel and chassis movements would be transmitted directly to the loading surface, triggering dangerous oscillations and jolts up to potentially causing loss of control of the vehicle or load. .

To avoid these problems, pneumatic type suspension for truck trailers is used, which exploit the different compressibility of a gas and improve comfort and stability both empty and fully loaded.

These suspensions comprise a variable volume chamber, delimited by a flexible watertight membrane, and a fixed volume chamber, divided between them by means of a rigid flange.

Said variable volume chamber and said fixed volume chamber are put in communication by two damping valves, in particular a compression valve and a recovery valve, which open according to the pressure difference between the two chambers.

Said damping valves are stably associated with said flange.

In addition to the two valves, there may be another gas passage with a fixed section, for example a hole.

Between said chambers, and through said hole and said damping valves, there is a continuous passage of gas in order to reduce the oscillations as soon as possible and compensate for the shocks and stresses coming from the wheels and the truck chassis.

When, for example, the truck wheels encounter an obstacle, the variable volume chamber compresses and the suspension, through said compression valve, transfers the compressed gas to the fixed volume chamber. Once the obstacle has been overcome, the variable volume chamber re-extends and the suspension, through the recovery valve, transfers the compressed gas from the fixed volume chamber to the variable volume chamber, restoring the equilibrium condition. The repetition of this double passage of gas allows to accelerate the restoration of the same pressure in both chambers and therefore to return to a condition of absence of oscillations.

Currently, said damping valves, or said compression valve and said recovery valve, have similar positioning and dimensions on the suspension flange, but are different in their geometries and components.

Said compression valve includes:

- a metal valve body provided with ports, adapted to be stably associated with said flange, provided with a stem;

- a stabilizing washer associated with the free end of said stem; - a diaphragm provided with a hole, able to slide along said stem which engages said hole, allowing or preventing the passage of gas from the ports of said valve body;

- a helical spring interposed between said diaphragm and said washer. The operation of the compression valve includes the following stages:

- the diaphragm leaves the closed position by moving vertically, sliding along the stem of the valve body and compressing the spring associated with it;

- the compression valve opens and the discharge takes place, ie the gas, through the ports of the valve body, passes from the compressed variable volume chamber to the fixed volume chamber;

- once the correct pressure has been restored inside the variable volume chamber, the distension of the spring returns to the closed valve condition, with the diaphragm in the closed position of the valve body ports.

Said recovery valve includes:

- a metal valve body, able to be stably associated with said flange, provided with an axial duct able to put said two chambers in communication;

- a diaphragm adapted to open or close said axial duct, allowing or preventing the passage of gas between said two chambers, provided with a stem sliding in said axial duct;

- a stabilizing washer associated with the end of said stem opposite to said diaphragm;

- a helical spring interposed between said valve body and said washer.

The operation of the recovery valve includes the following phases:

- the gas from the fixed volume chamber pressing on the diaphragm raises the stem inside the axial duct of the valve body by compressing the spring;

- the diaphragm raises and frees the axial duct of the valve body from which the gas can flow, in suction, which will increase the pressure inside the variable volume chamber until a condition of equilibrium is reached between the two chambers;

- once this equilibrium pressure value has been reached, the spring re-extends, lowering the washer which drags the diaphragm with it until the valve body closes.

These compression and recovery valves have some limitations and disadvantages, mainly due to their geometry, their overall dimensions and their assembly complexity.

In fact, each valve has different components, each of them produced with specific molds or processes.

Such complex damping valves are therefore disadvantageously very expensive and difficult to assemble and position on the flange without running the risk of assembly errors.

Presentation of the invention

The purpose of the invention is to overcome these limits, realizing a damping valve that can be used in pneumatic suspensions that has the same dimensions, both bivalent, usable both as a compression valve and as a recovery valve, which is therefore universal, simplified in number of components and therefore in its assembly, and consequently cheaper and more reliable.

The purposes are achieved with a damping valve for pneumatic suspension of trailers for trucks, where said suspension is adapted to connect a first and a second mechanical element with the possibility of reciprocal displacement and comprises a first chamber and a second chamber containing a gas and divided between them by a rigid flange,

where said damping valve is adapted to be associated with said flange and comprises:

- a cylindrical valve body, comprising a first mouth and a second mouth for the passage of said gas between said first and said second chamber;

- an actuation mechanism of said valve adapted to cooperate with said valve body to allow or avoid the passage of gas through it, as a function of the pressure difference between said first and said second chamber,

and where said damping valve is characterized in that: - said actuation mechanism comprises a diaphragm, a stem associated with said diaphragm and a first helical spring acting elastically between said diaphragm and said valve body;

- said valve body comprises a central sleeve within which said stem slides, where said sleeve is connected internally in a punctual manner to said valve body so as to define ports for the passage of gas through said valve body;

- said valve body comprises an internal conformation symmetrical with respect to a median plane transversal to said sleeve, so that said diaphragm can cooperate indifferently with said first mouth or said second mouth of said valve body and so that the use of said valve damping is bivalent as a function of its internal mounting orientation.

According to a first aspect of the invention, said drive mechanism comprises a washer stably associated with the free end of said stem.

In a possible variant, said stem comprises an undercut and said actuation mechanism comprises a quick locking ring for fixing said washer against the undercut of said stem.

According to a further aspect of the invention, said valve body comprises ribs protruding from its internal surface to which said sleeve is associated.

Further, said sleeve comprises two opposite annular seats adapted to indifferently house one end of said first helical spring.

Advantageously, said diaphragm comprises a frusto-conical or curvilinear portion facing towards said stem, the inclination of which can determine the passage of gas.

In a preferred variant of the invention, said damping valve comprises a support collar on said flange, obtained on the external surface of said valve body, and stable fastening means to said flange.

Alternatively, said stable fastening means comprise a retaining ring adapted to be fitted on said valve body on the opposite side of said collar with respect to said flange, or said stable fastening means comprise teeth formed on the external surface of said valve body able to cooperate by interference with said flange.

According to a possible variant of the invention, said actuation mechanism comprises a second helical spring, acting elastically between said diaphragm and said valve body, coaxial to said first spring and having an elastic force lower than it so as to be able to adjust the opening force of said valve.

The advantages of the damping valve according to the invention are evident:

- the internal symmetry of the valve body allows the use of the same components for the drive mechanism, both for the compression valve, with exhaust function, and for the recovery valve, with suction function;

- the valve is therefore bivalent and can perform both functions depending on the mounting orientation of its internal components, while the fixing to the rigid flange of the suspension always takes place in the same direction;

- the overall dimensions of the two valves inside the suspension are substantially the same;

- the volume inside the valve body, useful for the passage of gas, is greater in favor of a better efficiency of the valve itself;

- by reducing the number of components, the entire valve assembly system has been simplified;

- it is possible to mount the valve on the same side of the flange both in the case of a compression valve and in the case of a recovery valve; - it is possible to mount the valves without the aid of third party systems such as sealing rings, for example by means of special teeth;

- production times and costs have been reduced;

- with the simplifications made it is possible to replace some metal components with plastic parts, lightening the valve and further reducing costs.

Brief description of the drawings

These and other advantages will be more evident in the following, in which a preferred method of carrying out the invention is described, by way of non-limiting example, and with the help of the figures where:

Figs. 1-3 represent, respectively in axonometric view, in exploded axonometric view and in plan view from above, a damping valve for air suspension according to the invention, in the configuration of a compression valve;

Figs. 4 and 5 show, in longitudinal section along two different vertical planes, the modular valve of Fig.1;

Figs. 6-8 represent, respectively in axonometric view, in exploded axonometric view and in plan view from above, a modular valve for pneumatic suspension according to the invention, in the configuration of the recovery valve;

Figs. 9 and 10 show, in longitudinal section along two different vertical planes, the modular valve of Fig.6;

Fig. 11 represents, in plan view from above, the flange of a pneumatic suspension of trailers on which the valves of Figs are mounted. 1 and 6;

Figs. 12a and 12b show, in section along a vertical plane, an example of a pneumatic suspension of truck cabs on which the two damping valves of Fig. 1 (compression valve) and Fig. 6 (recovery valve) are mounted , in two different phases of work;

Fig. 13 represents, in longitudinal section along a vertical plane, a damping valve according to a possible variant of the invention.

Detailed description of preferred ways of implementing the invention

With reference to the Figures, a damping valve 100, 200 is shown which can be used in an air suspension applicable to truck trailers, in particular heavy vehicles such as lorries or trucks.

In general, this type of pneumatic suspension is suitable for connecting a first and a second mechanical element with the possibility of reciprocal movement, such as the wheel axle and its trailer.

For the purpose of the present invention, said suspension substantially comprises:

- a first chamber A with variable volume bounded by flexible walls, such as for example a rubber membrane, and a second chamber B with fixed volume, separated from each other by a rigid perforated flange 1 and containing a gas under pressure;

- two damping valves 100, 200 associated with said perforated flange 1 (illustrated in Fig. 11), designed to modulate the passage of gas from one chamber to another.

As shown in the Figures, said damping valve 100, 200 comprises a cylindrical and rigid valve body 2, comprising a first mouth 3 and a second mouth 4 for the passage of said gas. Said valve body 2 comprises a central sleeve 8, coaxial to it, internally connected in a punctual way to the internal surface of said valve body 2 so as to provide ports 9 to allow free passage of the gas through them.

As is particularly evident from the exploded views of Figs. 2 and 7 and from the sections of Figs. 4 and 9, said valve body 2 comprises curvilinear profiles or ribs 12 protruding from its internal surface designed to connect the latter to said sleeve 8.

Said ribs 12 ensure the fastening of the sleeve 8 leaving wide openings 9 inside the valve body 2 to facilitate the passage of gas.

Said valve body 2 comprises an internal conformation symmetrical with respect to a median plane π transverse to said sleeve 8.

Said damping valve 100, 200 further comprises an actuation mechanism adapted to cooperate with said valve body 2 to allow or prevent the passage of gas through it.

In particular, said drive mechanism slides inside said sleeve 8.

Said drive mechanism includes:

- a circular diaphragm 5,

- a stem 6 associated with said diaphragm 5 and projecting orthogonally therefrom, comprising an undercut 16 disposed in proximity to its distal end with respect to said diaphragm 5; - a first helical spring 7 acting elastically between said diaphragm 5 and said valve body 2;

- a washer 10 stably associated with the free end of said stem 6;

- a quick locking ring 11 for fixing said washer 10 against the undercut 16 of said stem 6.

Said diaphragm 5 has a diameter substantially equal to the diameter of the ports 3, 4 of said valve body 2 so that it can cooperate indifferently with them and so that the use of said valve 100, 200 is bivalent according to the mounting orientation. of the diaphragm 5 on the valve body 2.

As particularly evident from the sections of Figs. 4-5 and 9-10, said diaphragm 5 comprises a frusto-conical portion 15 turned towards said stem 6 able to calibrate the outflow of gas through said valve body 2.

Advantageously, said diaphragm 5 and said stem 6 are made of self-lubricated plastic material, thermally stable and insensitive to humidity variations, such as for example acetal resins loaded with self-lubricating elements.

Said first helical spring 7 is stably associated with said washer 10 and said sleeve 8.

In particular, said sleeve 8 comprises a central stiffening rib 18 protruding in its median transverse plane π, in which two opposing annular seats 28, 38 are obtained, suitable to indifferently house one end of said first helical spring 7.

Said modular valve 100, 200 comprises a collar 13 for resting on said flange 1, obtained on the external surface of said valve body 2, and means for stable fixing to said rigid flange 1, so that said valve 100, 200 can be fixed to the the same way to flange 1 regardless of the orientation of the diaphragm 5.

In the variant shown:

- said stable fastening means comprise gripping teeth 14 obtained on the external surface of said valve body 2 able to cooperate by interference with said perforated flange 1;

- said collar 13 comprises solutions of continuity 23 and its support is therefore of the discontinuous type so as to alternate with the gripping teeth 14 which instead act by locking the valve body 2 in the opposite direction.

Alternatively, said stable fastening means could instead comprise a retaining ring, so-called seeger ring, adapted to be fitted on said valve body 2 on the opposite side of said collar 13 with respect to said flange 1. In this variant, the valve body 2 should have a dedicated seat in place of the teeth.

With particular reference to Figure 13, said drive mechanism comprises a second helical spring 17, also acting elastically between said diaphragm 5 and said valve body 2.

Said second helical spring 17 is coaxial to said first spring 7 and has an elastic force lower than it.

Also said second helical spring 17 is stably associated with said washer 10 and said sleeve 8; said sleeve 8 in fact comprises two further annular seats 48, 58 opposed to each other and adapted to indifferently house one end of said second helical spring 17.

In this variant, said first spring 7 is not directly connected to said washer 10 as it acts on said washer only at a later time.

Said two helical springs 7, 17 come into operation in two different times: when the damping valve 100, 200 must open to allow the passage of gas for reduced pressure variations only said second helical spring 17 comes into operation; in the event of higher pressures, the first helical spring 7 also intervenes.

The operation of the damping valve 100, 200 according to the invention is described below with particular reference to the sections of Figs 12a and 12b.

Figure 12a illustrates the moment in which the suspension works to dampen a vibration that would be transmitted to the truck trailer due to an obstacle, such as a curb, encountered by the truck itself along its travel path.

The first variable volume chamber A is squeezed and the gas inside it is compressed. Once a certain pressure value has been reached, the gas flows into the second chamber B at a fixed volume through the compression valve 100 which is therefore in an open configuration, as well as through the bypass hole 19 which is present in flange 1. The corresponding recovery valve 200 is in the closed configuration.

Figure 12b instead illustrates the case in which inside the second fixed volume chamber B there is too high a pressure and the gas must pass into the first variable volume chamber A through the recovery valve 200 which is therefore in an open configuration. . The corresponding compression valve 100 is in a closed configuration.

Claims (10)

CLAIMS 1) Damping valve (100, 200) for pneumatic suspension of trailers for trucks, where said suspension is adapted to connect a first and a second mechanical element with the possibility of reciprocal movement and comprises a first chamber (A) and a second chamber ( B) containing a gas and separated from each other by a flange (1), where said damping valve (100, 200) is adapted to be associated with said flange (1) and comprises: - a cylindrical valve body (2), comprising a first mouth (3) and a second mouth (4) for the passage of said gas between said first (A) and said second (B) chamber; - an actuation mechanism of said valve (100, 200) adapted to cooperate with said valve body (2) to allow or prevent the passage of gas through it as a function of the pressure difference between said first (A) and said second ( B) chamber, and where said damping valve (100, 200) is characterized by the fact that: - said actuation mechanism comprises a diaphragm (5), a stem (6) associated with said diaphragm (5) and a first helical spring (7) acting elastically between said diaphragm (5) and said valve body (2); - said valve body (2) comprises a central sleeve (8) within which said stem (6) slides, where said sleeve (8) is punctually connected internally to said valve body (2) so as to define ports (9 ) for the passage of gas through said valve body (2); - said valve body (2) comprises an internal conformation symmetrical with respect to a median plane (π) transversal to said sleeve (8), so that said diaphragm (5) can cooperate indifferently with said first mouth (3) or said second ( 4) mouth of said valve body (2) and so that the use of said damping valve (100, 200) is bivalent according to its internal mounting orientation. 2) Damping valve (100, 200) according to claim 1, characterized by the fact that said drive mechanism includes a washer (10) stably associated with the free end of said stem (6). 3) Damping valve (100, 200) according to claim 2, characterized in that said stem (6) comprises an undercut (16) and said actuation mechanism comprises a quick locking ring (11) for fixing said washer (10) against the undercut (16) of said stem (6). 4) Damping valve (100, 200) according to claim 1, characterized in that said valve body (2) comprises ribs (12) protruding from its internal surface to which said sleeve (8) is associated. 5) Damping valve (100, 200) according to claim 1, characterized by the fact that said sleeve (8) comprises two opposing annular seats (28, 38) suitable to indifferently house one end of said first helical spring (7). 6) Damping valve (100, 200) according to claim 1, characterized in that said diaphragm (5) comprises a frustoconical or curvilinear portion (15) facing towards said stem (6), the inclination of which can determine the passage of gas . 7) Damping valve (100, 200) according to claim 1, characterized in that it comprises a collar (13) resting on said flange (1), obtained on the external surface of said valve body (2), and fixing means stable to said flange (1). 8) Damping valve (100, 200) according to claim 7, characterized in that said stable fixing means comprise a retaining ring adapted to be fitted on said valve body (2) on the opposite side of said collar (13) with respect to to said flange (1). 9) Damping valve (100, 200) according to claim 7, characterized by the fact that said stable fixing means comprise teeth (14) obtained on the external surface of said valve body (2) able to cooperate by interference with said flange (1 ). 10) Damping valve (100, 200) according to claim 1, characterized in that said actuation mechanism comprises a second helical spring (17), acting elastically between said diaphragm (5) and said valve body (2), coaxial to said first spring (7) and having an elastic force lower than it so as to be able to adjust the opening force of said valve (100, 200).