Patent Application
20170314554
[Not Applicable]
It is a hydraulic pump of positive displacement, that functions with a non reciprocating piston of double effect (suction and unloading). This pump is expected to provide a fixed volume of liquid with high pressure. It also works as a hydraulic motor when hydraulic pressure is supplied.
Hydraulic pumps that are used to displace volumes of liquid under high pressure are called positive displacement pumps. These pumps displace the fluid by reducing the volume of a chamber.
Considering the mechanical element used to displace the fluid, pumps are given different names such as: piston pump, gear pump, vane pump, lobe pump or screw pump. Each of these pumps has differences in the amount of volume that can be displaced at a time of work and the volumetric efficiency.
Of all the aforementioned pumps, piston pumps are those that can displace more volume with greater pressure and better performance. However, they have drawbacks that limit them to a small range of applications. Piston pumps do not maintain constant pressure and volume due to the reciprocating function of the piston, nor are practical for use as a hydraulic motor.
To use the high efficiency and performance of the piston in an industrial setting, there are a variety of pumps with very sophisticated technology that can achieve fixed flow with constant high pressure and a good efficiency, but are very large, heavy, occupy large space and have many moving parts. These characteristics limit their use to a small range of applications, among these include the radial piston pump in E. E. Cook et al, U.S. Pat. No. 3,413,929. And the Axial Piston Pump in Wusthof et al., U.S. Pat. No. 4,838,765.
Hydrostatic transmissions are constructed with positive displacement pumps. In these transmissions, the hydraulic pump provides a flow of pressurized oil that is sent through special conduits to the hydraulic motor, where it is converted into mechanical energy that is transmitted to the workplace. Its key advantage is that it can transmit energy over long distances (far from the motor pump), something that is not possible with a mechanical transmission.
The most suitable pumps for hydraulic transmission are: gear pump, vane pump and axial piston pump. However, the technical characteristics of these pumps limits them to heavy industry. Hydraulic transmission also has a lesser performance than the mechanical transmission that makes it a high cost method.
In order to extend its range of applications efficiently to other branches of industry such as, in the automotive, aviation, and transportation in general, hydrostatic transmissions require hydraulic pumps and motors with less weight, less technical complexity, smaller size and better performance than hydraulic pumps and hydraulic motors that currently exist.
Although the piston is the most efficient system to add energy to the fluid it displaces, and can also receive, with great efficiency, energy from the liquid (with only small energy losses due to leakage and friction), it can not be used as a hydraulic motor, because it need lots of parts to convert reciprocating linear motion to rotary motion and valves to the admission and expulsion of the liquid.
The use of a non-reciprocating rotary-displacement hydraulic piston pump as a hydraulic motor would be useful for power generation industry. This because it can convert hydraulic pressure and flow into torque directly and with great efficiency. And thus transmit, with high efficiency, its rotational force directly to electricity generation.
The object of this invention is to make the piston generate a non-reciprocating stroke motion, so it can act with constant positive displacement.
Another object of the present invention is to provide a hydraulic pump with a piston which can directly convert the rotational force into hydraulic power and conversely hydraulic power may be converted into rotational force. Without intermediate mechanisms to perform this operation.
It is therefore an object of this invention to substantially reduce the pump size and simplify assembly, both characteristics which reduce the cost of the piston pumps.
It is yet another object of this invention to achieve constant positive displacement of the piston, thus increasing its efficiency when used in the transformation of potential energy of liquid to mechanical energy, or on the conversion of mechanical energy of rotation to hydraulic power.
It is also an object of this invention to provide a hydraulic pump of a piston driven by a rotational force in a constant direction, which can keep the admission and expulsion without causing pulsations.
It is a further object of this invention to build a hydraulic pump of a piston that can be used effectively as a hydraulic motor when hydraulic pressure is supplied.
It is an additional object of this invention to build a pump capable of operating with a fixed displacement piston (non-reciprocating) in order to use the resulting high efficiency and performance in the production of electrical power.
It is still another object of this invention to provide a pump which has a fixed flow with constant high pressure and a good efficiency, while it is mechanically simple and compact.
It is yet another object of the invention to provide a pump that can be used to improve performance and simplify the construction of hydraulic drive systems of the wheels.
It is thus another object of this invention to simplify construction and improve the performance of the hydrostatic transmission to expand its range of applications efficiently in automotive industry, and transportation in general.
Yet another object of this invention is to create a hydraulic pump which can use the energy from a hydraulic accumulator to move, with high efficiency, an electric generator when needed.
The present invention relates to the parts, construction and operation of a positive displacement hydraulic pump powered by a non-reciprocating piston. The operation of the pump will produce a fixed volume and high pressure. It can also reverse the direction of rotation to provide its pumping capacity in both directions, as well as be used to work as a hydraulic motor when hydraulic pressure is supplied.
This is a double-acting piston that moves in one direction within a toroidal chamber in which two movable walls isolate the suction and discharge cavities.
The piston is joined to the rim of a wheel. When the wheel rotates, the piston moves through the interior of the toroidal chamber of a casing in which the rim of the wheel is an integral part of the toroidal chamber.
Two movable walls on opposite sides of the diameter of the casing and parallel to the wheel shaft, moving inside the toroidal chamber to divide it into two cavities. These movable walls are moved by a cam mechanism, guided by the wheel.
The volume of a cavity of this camera increases by moving the piston, causing suction and thus propelling the fluid into the cavity through the inlet port. The port is in the wheel rim, close to the side of the piston and has access to one of the circular plane surfaces the wheel.
The other side of the piston reduces the volume of the other cavity, forcing the fluid it contains and transporting it to the outside through the discharge port. The discharge port is in the rim of the wheel near of the piston and has access to the other circular plane surface of the wheel.
When the piston approaches, the movable wall is withdrawn from the piston chamber to allow the piston to continue its trajectory. At this time, the other movable wall is closes the piston cavity from the opposite diametrical side maintaining both the suction cavity and the unloading cavity.
When the piston passed by the place of the open movable wall, the movable wall starts to move towards the toroidal chamber to isolate two cavities. When it finishes closing the cavities, the other movable wall is removed from the piston chamber, to allow the piston continue its trajectory.
At all times of the rotation of the piston, the movable walls maintain a constant working cavity on each side of the piston. To one side of the piston, the suction cavity and on the other side the unloading cavity. This function is repeated in all revolutions.
FIG. (1). Shows the front view askew of the pump, without cap, to see parts of the internal mechanism.
FIG. (2-A). Cut side of the pump for interior view: movable wall, rods, cam, wheel, casing, cap, shaft.
FIG. (2-B). Front view of the mechanism that moves the movable walls: cams, rods and movable walls.
FIG. (2-C). Shows the view lopsided the cam and movable walls.
FIG. (3-A). Front view of the cap of the pump, cam, the rods and cap of the rods.
FIG. (3-B). Side cut view of the cap of the pump, cam, the rods and cap of the rods.
FIGS. (4-A), (4-B), (4-C) and (4-D). Views of the functioning of movable walls at different times of the rotation of the piston.
FIG. (5). Ensemble of the pump. All pump parts separated in order to be assembled.
A preferred embodiment of the closure of the present invention is illustrated in FIG. (1) and FIG. (2).
FIG. (1) shows the front-askew view of the pump, without the cap, to see the internal mechanism.
The piston (3) is fixed to the wheel rim (12). On the wheel rim (12), and near one side of the piston (3), is the suction port (9), which has access to the lateral face of the wheel (12).
On the wheel rim (12) and near the other side of the piston (3), is the discharge port (10) which has access to the other side face of the wheel (12).
The wheel has an axle (14) which rotates within the axle hole (19) which allows the wheel to slide to the piston by the internal walls of the housing.
The two movable walls (2) are in its cavities for displacement (8), each located on both sides of the casing (1).
The screw holes (13), are for attaching the pump cap to the casing. Pump cap (15) in the FIGS. (2-A, 3-A, 3-B and 5).
When rotating, the cam (6) drives the rods (7). These through the access for rod (17), in the pump cap, are inserted into the hole for rod (11) to displace the movable walls (2) within the displacement cavity (8) in the casing. We can see how the rods (7), by means of an deflection, are connected to the two levels of cam (6).
FIG. (2-B) shows the front view of the cam (6) and rods (7), inserted in holes for rod (11) in movable walls.
FIG. (2-C) shows the side-tilted view of cam (6). In this view it can be seen that the cam has two levels, each of which is responsible for half of the movement of the rods.
FIGS. (2-A), (2-B) and (2-C) show movable walls (2), hole for the rod (11) and the evacuation conduit (18). This last one is a channel along one side of the movable wall (2) which helps to drain the liquid at the time of displacement of the movable wall from displacement cavity (8) toward the piston chamber or vice versa.
FIG. (1). When rotating the wheel (12), the piston (3) slides along the inner walls of the toroidal camera made of the inner wall (20), bottom of the casing (21) and it's corresponding area on the cap of the pump (FIG. (5)(15)).
The movable wall (2) located on the bottom of FIG. (1) and FIG. (2-A), is out of the displacement cavity (8) making sealing contact with the rim of the wheel (12) and is limiting the stroke of the piston (3).
When the wheel (12) rotates in one direction, one side of the piston (3) increases the capacity of the cavity formed between: the movable wall (2) located at the bottom of the FIG. (1), the rim of the wheel (12), the inner wall (20), housing bottom (21) and the surface of the pump cap (FIGS. (3-A, 3-B)(15)).
By increasing the capacity of this camera, it reduces the pressure, creating a negative pressure which has access to a side face of the wheel (12) through the port of suction (9) and in this part, is the inlet (4), (FIG. (2-A), by where this negative pressure impels the liquid into the pump. Inlet (4) in FIGS. (2-A and 5).
In FIG. (1), the movable wall (2) located on the top of this figure, is inside the displacement cavity (8) to allow passage to the piston (3) through this area.
The side of the piston (3) that moves in direction of the movable wall (2) at the bottom of FIG. (1), reduces the space of the cavity formed between: the movable wall (2) located on the bottom of FIG. (1), the rim of the wheel (12), the inner wall (20), bottom of the casing (21) and its equivalent opposite surface on the pump cap (15) FIGS. (3-A, 3-B).
As the piston reduces the space in the cavity, it forces the contained liquid to flow out through the discharge port (10) in the rim of the wheel, toward the chamber formed between: (FIG. (2-A) one side of the wheel (12) and the pump cap (15). In this chamber, the liquid flows to the outside of the pump body by the outlet (5) in the pump cap.
The operation of the movable walls (2), at different moments of the rotation of the piston (3) is shown in FIGS. (4-A), (4-B), (4-C) and (4-D). To the right of these figures can see the cam position at the time of rotation.
In FIGS. (4-A), (4-B), (4-C) and (4-D). The extensions to the left of the rods are inserted into the hole (11) to transmit the movement of the cam to the movable walls (6).
The pump is located to the left of each of these FIGS. (4A, 4B, 4C, 4D) and shows the front, without cap, to observe the position of the movable walls (2) at different angles of rotation of the piston. Movable walls (2) are within the of displacement cavity (8), in the casing (1) of the pump.
FIG. (4-A). In this example, the wheel rotates clockwise. The movable walls (2) are out of the displacement cavity (8) and are making contact with the surface of the wheel rim (12), thereby isolating the loading cavity and the discharge cavity of the piston.
The piston head (that surface which faces the direction of rotation), exerts a force on the fluid that is in that cavity and expels it through the discharge port.
In FIG. (4-A), the surface opposite to the piston head is moving away from the movable wall (2) located at the bottom and is increasing capacity in this cavity. This creates a negative pressure that suctions the liquid through the inlet port.
In the piston's (3) trajectory, from the point where it is in FIG. (4-A) to the point shown in the FIG. (4-B), the cam (6) has rotated with the shaft (14) of the wheel (12). It has moved the rod (7) and this in turn shifted the movable wall (2), which is on the top of the figure, into its displacement cavity (8).
The movable wall (2), located at the top of the FIG. (4-B), is now inside its displacement cavity (8). This will allow the piston (3) clear passage through this zone that is part of its trajectory.
The movable wall (2) located on the bottom of this figure, remains displaced outwards from its displacement cavity (8) and is making contact with the surface of the wheel rim. This movable wall (2) along with the piston (3) isolate the loading cavity and discharge cavity.
In FIG. (4-B), the piston (3) is located in front of the displacement cavity (8) at the top of this figure. The side of the piston (3) is longer than the width of the displacement cavity. This prevents the passing of liquid from the discharge cavity to the loading cavity through the displacement cavity.
On the trajectory traversed by the piston from the position in FIG. (4-B) up to the position shown in FIG. (4-C), the cam rotated along with the wheel shaft and moved the rod which guides the movable wall at the top of this Figure. This in turn withdrew the movable wall out of the displacement cavity and over to the rim of the wheel.
FIG. (4-C) the piston is at the halfway point of rotation between the movable wall (2) at the top of the Figure and the movable wall (2) that is at the bottom of this Figure.
FIG. (4-C). The two movable walls (2) are displaced out of the displacement cavity (8) and are making contact with the rim of the wheel (12). In this position, they are isolating, along with the piston (3), the loading cavity and discharge cavity.
On the trajectory traversed by the piston from its position in FIG. (4-C) to the position shown in FIG. (4-D), the cam (6) has acted on the rods (7) and these in turn shifted the movable wall (2), that is at the bottom of this Figure, inside the displacement cavity (8).
In FIG. (4-D), the piston (3) crosses the area of the movable wall (2) located at the bottom of this Figure. The movable wall (2) located at the top of this Figure is isolating along with the piston (3), the charge and discharge cavities.
In FIG. (4-D), the cavity formed between the movable wall (2) located on the top of this figure and the rear side of the piston (3) is the suction cavity. On the other hand, the cavity between the leading face of the piston (3) and the movable wall (2) at the top of the Figure is the discharge cavity.
While the piston (3) traversed the trajectory from its position in FIG. (4-D) to the position shown in FIG. (4-A), the cam (6) has acted on the rods (7) and these have shifted the movable wall (2) located at the bottom of FIG. (4-A) out of its displacement cavity until it touched the rim of the wheel, hermetically sealing this point on the piston displacement chamber.
At all times of the piston stroke, the movable walls, along with the piston, maintain both a loading cavity and a discharge cavity. This function is repeated in all revolutions.
FIG. (3-A) shows the front view of the pump cap (15). And FIG. (3-B) side view of the pump cap. The holes (13) for the screws that hold the pump cap to the casing.
The cam (6), which is fixed to the shaft (14) and rotates with it on the outside of the cap (15). The rods (7) act with the rotation of cam (6) to move the movable walls (2).
Still on FIGS. (3-A, 3-B), the pump outlet (5) (or pump inlet depending on the direction of rotation of the wheel).
The cap for the rod (16) is to seal the area of the pump cap (15), where the slot (17) for the rod is.
The rod inlet seal (22), is where the rod is inserted on cap of the rod (16). This place has to be sealed avoid leakage of fluid and allow movement of rod.
FIG. (5) shows all the pump parts, separated in order of assembly, wherein the casing (1) has the axle hole (19) at its inner bottom (21). The axle hole (19) is centrally located to the circumference of its inner wall (20).
Two displacement cavity (8), each located on both sides of the diameter of the circumference of the casing. Inlet (4) for admission if the wheel (12) rotates clockwise.
The wheel (12) has the piston (3) on its rim. On one side of the piston (3), we find the suction port (9) which has access to one side of the wheel. On the other side of the piston, the discharge port (10) that has access to the other side of the wheel. Such ports are for suction or discharge of the liquid, depending on the direction of rotation of the wheel. the shaft (14) is located in the center of its circumference. Movable walls (2) are on diametrically opposing sides of the circumference of the wheel.
The pump cap (15), has at the center of its circumference an axle hole (19) for the shaft (14). The outlet (5) is for output of fluid when the wheel (12) rotates clockwise. The rod (7) passes through the access to the rod (17) and connects to the movable wall (2) on the hole for rod (11).
In the cam (6) one can see that it has two levels, to act on the contact surfaces of the rods (7). The center shaft (19) is where the shaft (14) of the wheel (12) is inserted. The cam (6) is fixed to the shaft (14) by screw, bolt or other means in order to rotate with the shaft.
The rods (7) have a deviation in their quadrangular parts. This deviation is to make contact with the two levels of the cam (6). At the other end, bent at an angle, the rods are inserted into the hole for rod (11) and into the movable walls (2).
The caps of the rods (16) seal the area of the pump cap (15) with the access to the rod (17) by means of the rod inlet seal (22), where the rod (7) is inserted.
