EP1985859A2

EP1985859A2 - Hydraulic pump system with integrated distributor valve

Info

Publication number: EP1985859A2
Application number: EP08398005A
Authority: EP
Inventors: Rui Jorge Da Silva Bernardes
Original assignee: ABER- Embraiagens e Commandos Hidraulicos Antonio Bernardes Lda
Current assignee: ABER- Embraiagens e Commandos Hidraulicos Antonio Bernardes Lda
Priority date: 2007-04-24
Filing date: 2008-04-24
Publication date: 2008-10-29
Also published as: EP1985859A3; US20080267794A1

Abstract

The present invention is concerning a hydraulic pump system with integrated distributor valve, which is generally applied in a hydraulic circuit normally constituted of an oil deposit (39), a cylinder (40), a module of Pneumatic control (41), and a hydraulic pump with integrated distributor valve (42). The system object of the present invention presents a reduction of the accidents and ruptures in the gear box, operates with higher pressures, reduces the vibrations and prevents clearances and consuming of the pump. The present invention is applicable mainly to power take off's (43) that are located in the gear box of the trucks.

Description

Technical field of the invention

The present invention is about a hydraulic pump system with integrated distributor valve constituted of two parts, which is normally applied, directly or indirectly, to power take off's that are located in the gear box of the trucks.

Background of the Invention

The present invention is about a system of hydraulic pump with integrated valve, which for its characteristics of conception and functioning is different from the systems found in the market.
The systems of hydraulic pump with integrated valve presented in the market have a structure essentially composed of 3 (three) parts, which are the front cover, the body and the back cover; while the present invention is composed of two parts, which are the cover and the body. This type of structure differs from the divulged in the present invention as, for example, in order to have a functioning on a work pressure of 175bar they need to have an approximated weight of 32,2Kg, and they still need cylinders of superior dimension.
The requests of patent EP 0018216 and GB 1013263 are two examples of hydraulic pumps with 3 (three) parts with improved devices of retention of the liquid in the transmission chamber, but with the inconveniences above mentioned.
The solution presented in the herewith request allows the construction of smaller and lighter systems of pumps with integrated valve and the possibility of working without relief valves in the front cover. In fact, this new system of hydraulic pump with integrated valve has differences on conception and functioning that translate great economy in the conception, assembly, and increase of efficiency and safety.

Summary of the invention

The system of the present invention includes a hydraulic pump capable of operating under high pressures conditions with the aid of compensating plates that are located in the extremities of the generating elements of power or load.
The aim of the present invention is the supplying of a solution for a pump system with integrated distributor valve, constructed in two parts, that are the grouping of the cover, which may be applied without the relief valves, and the body, which supports without any problem pressures up to 200 bar, with a maximum rotation of 1800rpm, for an approximated weight of 22Kg, for a pump of ±105cc. This system is normally applied to heavy mobile equipment.
The system object of the present invention presents the following advantages:

Due to the less weight, it reduces the accidents and ruptures in the gear box of the trucks;
It works under higher pressures which allow the use of cylinders with inferior diameters, that is, a more economical use;
It permits the reduction of the vibrations, allowances and consuming of the pump preventing this way damages and premature substitutions. It is estimated that, for pressures above 200 bar, there is a reduction of the damages in the order of 10-20%.
The possibility of not using relief valves in the front cover eliminates the peaks of pressure in this front cover. The front cover is the weakest part of the pump and therefore must be protected against working failures. If the relief valves cease to exist and the lubrication and internal pressure peaks are made through the channel (44) of the pump body that connect the generating elements of power (7 & 10) through an internal hole along the element's (7) length to the tank (39), the leaking, the pressure peaks and the infiltration problems are suppressed.

Description of the Drawings

For a better understanding of the essence of the invention we hereby describe the attached figures, which present a preferential representation of the patent.
This way, the Figures represent:

Fig.1 - Front view of the set of the hydraulic pump with integrated distributor valve;
Fig.2 - Axial cut view of the system of the hydraulic pump with integrated distributor valve - plan of cut coincident with the axles of the generating elements of power or load;
Fig.3 - Transversal cut view of the system of the hydraulic pump with integrated distributor valve - horizontal cut plan and coincident with the distribution axle;
Fig.4 - Detail of the mechanical command - option in the purchase of the equipment;
Fig.5 - View of the cut of the pneumatic command of the distributor valve;
Fig.6 - Front view and details of the section of the compensating plates of pressure and of the seal;
Fig.7 - View of the anti return system, composed of a valve plug and a sphere;
Fig.8 - View of cut of the relief valve with incorporated anti return, composed of a screw, a nut, a pressure control screw, two springs, a piston, a sphere carrier, two spheres, a valve plug, a sleeve and three elements of sealing;
Fig.9 - Exploded perspective of the oil-hydraulic pump with incorporated distributor valve;
Fig.10- Perspective of the oil-hydraulic pump with incorporated distributor valve - fixation flange and motion transmission;
Fig.11 - View under perspective of the oil-hydraulic pump with incorporated distributor valve - area of hydraulic connections;
Fig.12 - View under perspective of the functioning scheme of the hydraulic circuit with hydraulic pump and integrated distributor valve.
Fig.13 - Channel that links the generating elements of power - being one of them drilled longitudinally - to the tank, which allows the non-use of the check system in the cover of this pump's valve.

Description of the invention

The object of the present invention is a system of hydraulic pump with integrated distributor valve (42) that has at least the following elements:

two metal parts of which one part is the body of the pump (33) and the other the cover of the pump (1) ;
two generating elements of power or load (10) and (7), having the axle (7) a hole in its interior for lubrication of the sleeves or roll bearings and protection against internal pressure leaks, protecting this way the seal (3);
two compensating pressure plates (8), of which at least one has a seal (9);
at least one relief valve with incorporated anti return (14) in the body of the pump;
sealing system (3 & 6) to prevent oil losses and to guarantee the separation of the oil of the hydraulic system with the gear box and supporting high pressures;
at least four roll bearings or sleeves (5), two in the cover and two in the body, of which one of them can be in the front of the cover (1);
a distributor shaft (22) for guidance of the oil;
a command, represented in Fig.5, for pneumatic drive;
a spring (19) for repositioning of the pump shaft.

The compensating pressure plates (8) with seals (9) are located in the extremities of the generating elements of power or load and respectively maintained with the body of the pump (33) /cover of the pump (1); these can be made of bronze, aluminium or steel with projected bronze and have two drilled circular parts in the shape of a eight, in order to be able to compensate the pressure difference between the input and the output side, to which the two generating elements of power or load (10 & 7) are subject to. The seals of the compensating plates (9) made of polymer, have a rectangular section and can have inferior platforms in the extremities. The rectangular section is responsible for the sealing and the inferior platforms prevent the vibrations, as it can be observed in the details of Figure 6.
The generating elements of power or load (10 & 7) of the hydraulic pump system with integrated distributor valve (42) can be pistons or gear wheels.
The system of hydraulic pump with integrated distributor valve (42) is composed essentially of two main parts; the set aggregated to the cover (1) and the set aggregated to the body (33).
The set of the cover (1) has as function the guiding, sealing and supporting of the setting of the system of hydraulic pump with integrated distributor valve. In the cover (1) is assembled:

two sealing elements (3 & 6) which are responsible for preventing oil losses, guaranteeing the separation of the oil of the hydraulic system with the gear box, and supporting high pressures;
two sleeves (5) that assure the support to the centring and the good functioning of the generating elements of power or load (10 & 7);
a roll bearing (2) to improve the support of the output axle (10);
two rings (4 & 34) to guarantee the positioning and the good functioning of the elements (2 & 3);
it can have (or not) two check valves (11) responsible for the isolation of pressures and lubrication of the sleeves (5);
a channel (44) that binds the tank (39) to the sleeves for lubrication and protection against leaks of internal pressure.

The set of the body (33) has as function the inhaling of the oil of the deposit (39), carrying it internally from the pump to the distributor and sending it to the cylinder (40) or to the deposit (39). In the body (33) is assembled:

two sleeves (5) that guarantee the support to the centring and the good functioning of the generating elements of power or load (10 & 7);
two compensating pressure plates (8), of which at least one has a seal (9), that guarantees the sealing, isolation and prevents vibrations;
an output axle (10) and a gear axle (7) responsible for the generation of power or load, having the axle (7) a hole in its interior for lubrication of the sleeves or roll bearings of the cover (1), and protection against internal pressure leaks protecting this way the seal (3);
at least two bolts (13) to provide a centred assembly;
a relief valve with incorporated anti return (14), that controls and regulates the pressure and protects the pump and the cylinder from receiving pressure peaks; it can have enough dimension so that the hydraulic pump system with integrated valve will not need the cable to set in motion the oil flow distributor axle (22) because the oil is taken directly from the pump to the tank, that is, this system might not need a system of end stroke valve.
five sealing elements [ (16), (21), (23), (24) and (35)] responsible for preventing losses of oil, guaranteeing the separation of the oil and supporting high pressures;
a spring (19) that repositions the distribution axle (22);
two support spring washers (18), in which the spring (19) is mounted;
a posterior cover (17), whose function is to protect the spring (19) and to lodge the sealing elements (16), the support spring washer (18) and the spring (19) ;
a distributor extension axle (15) that is mounted in the distribution axle (22);
a ring (20) to guarantee the positioning and the good functioning of the support spring washer (18) and of the spring (19);
a distribution axle (22) that guides the oil to the intended positions made by the user;
a piston (25) that together with the sealing elements (24) makes the sealing of the pneumatic command;
one shaft washer (26) and a screw (27) fix the piston (25) to the distribution axle (22);
a pneumatic command cover (28) receives the command.

In the case of choosing the mechanical command, it is necessary to proceed to the alteration of the command that consists of five operations, which are:

the substitution of the sealing element (24) for (32);
the insertion of a sealing element (16);
the substitution of the piston (25) for the mechanical control piston (31);
the substitution of the cover of the pneumatic command (28) for the cover of the mechanical command (30);
the substitution of the shaft O-ring (26) and the screw (27) for the mechanical shaft control of extension (29).

The admission of the system of hydraulic pump with integrated distributor valve (42) is made by the connection (36). The exit to the oil deposit (39) is made by the connection (37). The exit to the cylinder (40) is made by the connection (38). The element (39) is the oil deposit, necessary for the functioning of the whole hydraulic system. The element (40) is the cylinder of the system, which is set in motion by the oil coming from the system of the hydraulic pump with integrated distributor valve (42).
The pneumatic control (41) is used to set in motion the valve of the hydraulic pump system with integrated distributor valve (42). The hydraulic pump system with integrated distributor valve (42) is connected to the power take off (43) in order to get the rotation movement.
In this hydraulic pump system with integrated distributor valve (42), composed essentially of two parts, it is allowed the use of compensation plates (8) of the hydraulic pressure, which are lodged in cavities specifically created in the body (33) for the plates (8). Or either, the bigger the exerted pressure, the better is the compensation of the pump, allowing the operation under high pressures, namely between 170 to 200 bar, and with efficiencies above 85%.
As this system allows the use under high pressures, namely between 170 to 200 bar, cylinders with diameters inferior in 20% to the vulgarly used, that is, lighter and more economic, can still be used for these pressures.
In this way the hydraulic pump system with integrated distributor valve (42) can present significant reductions of the general exterior dimensions.
The system object of the present invention, presents efficiencies of about more 10% when compared with the conventional systems. The data obtained from tests consist of the measuring of the volume of oils at 1000rpm, according to the variation of the pressure.
The tests were carried out in a test machine of oil-hydraulic and in a truck under working conditions. This way, the load and unload of the trucks can be made by a platform, quickly (in average with an economy of 10% of the time) and safely. When in load (at 200bar) the new equipment fastens the basculation in 10%. There is the possibility of the pump working without any valve in the cover (1) due to the lubrication by the channel (44) between the shafts and the oil entrance (36) and the internal hole in the generating power shaft (7) that protects the seal (3) against leaks of internal pressure, which reduces the possibility of the oil of the hydraulic circuit to pass to the exterior of the pump in the area of the power generating shaft(10), in order to always protect the cylinder (40) against pressure peaks.
In the compensation plate (8) a bidirectional seal can be mounted (9), inserted in the hole along the perimeter of the mentioned plates (8), that makes the sealing from the admission to the pressure. The internal pressure itself helps the polymer to seal, remaining this way in its appropriate place without risk of rupture, because it has the capacity of eliminating the working vibrations.
The relief valve with incorporated anti return (14) is mounted at the exit of the pump, and has a relief valve of the direct circuit to the cylinder (40), protecting it against pressure peaks. The anti return hinders the return of the oil to the pump. The pressure points of the pneumatic part are isolated from the hydraulic pressure through connections to the oil deposit (39), for that the risk of oil passage to the pneumatic controls is null, and in general there will not be the necessity of end stroke valves, being enough a relief valve (14) for discharge of the flow rate of the pump (in not very high rotations), reducing this way the probability of occurrence of damage.
The user turns on the power take off, which sets in motion the hydraulic pump system with integrated distributor valve (42) through a rotation movement.
The distributor valve (42), which is integrated in the hydraulic pump, contains internal channels. In the hole of this valve is mounted the distribution axle that guides the oil under pressure through these channels to the oil deposit or to the cylinder.
The described representation of the hydraulic pump system with integrated valve is made as a non limitative example which can be subjected to modifications and variations handled by an expert person in the area, which are, however, protected under the scope of the invention, as defined by the claims that follow.

Claims

System of hydraulic pump with integrated distributor valve, characterized for being set up by two main parts, the set aggregated to the cover and the set aggregated to the body, of which the set of the cover, which guides, seals and supports the setting of the system, is composed of:
- a body with internal channels for lubrication of the generating elements of power which are connected to the tank and the cover has also an internal channel for connection of the generating elements of power. This lubrication and liberation of the internal pressure peaks pass from the cover to the body channels through the internal hole of the generating element of power ;

- two sealing elements to prevent losses of oil and to guarantee the separation of the oil of the hydraulic system and the gear box;

- two sleeves that guarantee the support to centring and functioning of the generating elements of power or load;

- a roll bearing for the support of the output axle;

- two rings for the positioning and functioning of the sealing and rolling elements, respectively;

- it may have two relief valves responsible for the isolation of pressures; where the set of the body, that aspirates the oil of the deposit, carries it out internally from the pump to the distributor and sends it to the cylinder or to the deposit, as is composed of:
- two sleeves for the support, the centring and the functioning of the mentioned elements;

- two compensating pressure plates, located in the extremities of the mentioned elements, of which at least one possess a seal to seal, isolate and absorb vibrations;

- an output axle and a gear axle drilled trough its interior to allow to the lubrication of the roll bearings or sleeves and to protect the seal against internal pressure leaks, guiding these through its interior for a channel that internally leads them to the connection, responsible for generating power or load;

- at least two bolts so that it allows a centred assembly;

- a relief valve with incorporated anti return, mounted at the exit of the pump, that controls and regulates the pressure and protects the pump and the cylinder during all working situations that involve pressure peaks;

- sealing elements responsible for preventing losses of oil, guaranteeing the separation of the oil and supporting high pressures;

- a spring to reset a distribution axle;

- two support spring washers in which the spring is mounted;

- a posterior cover, that protects the spring and lodges the sealing elements, the support spring washer and the spring;

- a distributor axle of extension that is mounted in the distribution axle;

- a positioning ring of the support spring washer and of the spring;

- a distribution axle that guides the oil;

- a piston and sealing elements that make the sealing of the pneumatic command;

- one shaft washer and a screw to fix the piston to the distribution axle;

- a cover of pneumatic command.
Hydraulic pump system in accordance with claim 1, characterized for the compensating pressure plates being made of bronze, aluminium or steel with projected bronze.
Hydraulic pump system in accordance with claim 1, characterized for the compensating pressure plates, which are lodged in cavities specifically made in the body, being constituted of two drilled circular parts in the shape of eight, in order to be able to compensate the pressure difference, to which the two generating elements of power or load are subject to.
Hydraulic pump system in accordance with claim 3, characterized for the sealing of the compensating plates to be inserted in a hole along the perimeter of the plates and to possess a rectangular section responsible for the sealing and in the extremities can have inferior platforms responsible for the damping of the vibrations.
Hydraulic pump system in accordance with claim 1, characterized for the generating elements of power or load being pistons or gear wheels.
Hydraulic pump system in accordance with claim 1, characterized for having in the body of the pump the admission of the system made by the connection; the exit to the oil deposit made by the connection; and the exit to the cylinder made by the connection.
Hydraulic pump system in accordance with claim 1, characterized for having a pneumatic control for setting in motion the valve of the hydraulic pump system with integrated distributor valve.
The relief valve for peak pressures can have enough dimension so that the hydraulic pump system with integrated valve will not need the cable to set in motion the oil flow distributor axle because the oil is taken directly from the pump to the tank, that is, this system might not need a system of end stroke valve.