Hydraulic pump with variable flow and reversible direction of rotation

Abstract

The present invention relates to a hydraulic pump with variable flow and reversible direction of rotation having a simple configuration and comprising a casing, a rotary shaft, a platen, two pumping pistons, a drum with a pumping cylinder for each pumping piston, a plate between the drum and the casing and surrounding the shaft with an intake opening and a delivery opening, both being diametrically symmetrical, and the plate having a protrusion. The invention further comprises a first pin in a first housing of the casing and a second pin in a second housing of the casing, both transverse to the shaft and accessible from the outside. The first pin has a first length such that it contacts the protrusion and the second pin has a second length such that it contacts the protrusion, and when the first pin and the second pin change positions, the plate rotates and the pump is configured to operate in the opposite direction of rotation.

Description

[0001]VARIABLE DISCHARGE HYDRAULIC PUMP WITH REVERSIBLE DIRECTION OF ROTATION TECHNICAL FIELD OF THE INVENTION The present invention falls within the field of axial piston hydraulic pumps, specifically those with variable discharge and a reversible direction of rotation. BACKGROUND OF THE INVENTION Hydraulic pumps include axial piston pumps, which propel the fluid through the reciprocating motion of their pistons. One particular type is the variable discharge pump, which is achieved by varying the inclination of a swashplate on which pistons slide, maintaining contact, usually thanks to a guide that maintains pressure on the piston heads and a spherical joint, as described in patent number US4907408. Furthermore, another type of axial piston hydraulic pump allows the direction of rotation of the pistons to be reversed.having a distribution plate behind the drum with the pistons whose function is to optimize the flow of oil and which, when rotating, passes from a position where an intake orifice (also called a "port") becomes a discharge orifice and vice versa,The discharge port becomes the intake port. An example of this type of pump is shown in patent number US2016025081A1, which depicts a variable displacement pump in which the movement of the distribution plate is achieved by a hydraulic mechanism that moves the plate via a pin inserted axially into it. Another example of this type of pump is shown in patent number ES2399197T3, which depicts a variable displacement pump in which the movement of the distribution plate is achieved by means of a pin whose rotating end acts as a cam that moves the distribution plate. In hydraulic pumps with variable displacement and reversible rotation, the rotation of the distribution plate is achieved by means of a mechanism that operates independently or through manipulation.The mechanism in question is of a certain complexity. DESCRIPTION OF THE INVENTION The present invention is established and characterized in the independent claim, while the dependent claims describe other features thereof. The object of the invention is a hydraulic pump with variable displacement and reversible direction of rotation. The technical problem to be solved is to configure the pump to overcome the disadvantages of the prior art, having a simple configuration as an alternative to what is known. In view of the foregoing, the present invention relates to a hydraulic pump with variable displacement and reversible direction of rotation comprising a housing in which a rotating shaft is arranged, a plate inserted on the shaft and configured to oscillate about said shaft, and two pumping pistons, representing the minimum number of pistons, although it is usual to have a number of pistons such that they fill the circumference of the plate.with the pistons in sliding contact with the plate, normally by means of a spherical joint, a spring and a pressure guide, a drum fixed to the shaft so that it rotates with it, the drum includes a pumping cylinder for each pumping piston, each pumping cylinder configured so that the pumping piston can slide in it during the rotation of the drum, a plate disposed between the drum and the housing and around the shaft so that it can rotate about said shaft through a certain angle, the plate comprises an inlet opening configured for the passage of a fluid into the interior of the pump, which corresponds to an inlet nozzle in the housing, and a discharge opening configured for the passage of the fluid to the exterior of the pump, which corresponds to a discharge nozzle in the housing, the inlet opening being arranged on the plate diametrically symmetrical with respect to the discharge opening,and the inlet nozzle is arranged symmetrically with respect to the outlet nozzle, as is known in the prior art. The invention is characterized in that the plate has a protrusion; a first pin is arranged in a first housing recess, positioned transversely to the axis and accessible from the outside of the housing; a second pin is arranged in a second housing recess, positioned transversely to the axis, accessible from the outside of the housing and opposite the first pin; such that the first pin has a first length that contacts the protrusion and the second pin has a second length that contacts the protrusion, leaving the plate in a first position; when the positions of the first pin and the second pin are exchanged, the plate rotates, reaching a second position, and the pump is configured to operate in the opposite direction of rotation. Since the plate rotates when the pins are exchanged,These pins necessarily have different lengths. The pump thus described has a configuration different from what is known, simple to construct and operate, which is its main advantage and in line with the object of the invention. The terms "intake" and "discharge" are used to differentiate the openings and nozzles that accompany them. They function as terms for the direction of rotation of the pump, as represented in the figures of the embodiment described below. When the rotation is reversed, the terminology is retained, but its function is the opposite: the intake opening and nozzle perform the discharge function, and vice versa. Other advantages related to the characteristics of the dependent claims are stated below in the detailed exposition. BRIEF DESCRIPTION OF THE FIGURES This descriptive specification is supplemented by a set of figures illustrating the preferred embodiment.and never limiting the invention. Figure 1 shows an elevation and longitudinal section view of a pump of the invention. Cross-sections AA and CC are indicated. Figure 2 shows the elevation view of Figure 1, without sectioning, indicating cross-section BB. Figure 3 shows section AA of the pump shown in Figure 1. Figure 4 shows section BB of the pump shown in Figure 2. Figure 5 shows section CC shown in the pump of Figure 1. DETAILED EXPLANATION OF THE INVENTION Figure 1 shows a section view of a variable displacement, reversible hydraulic pump comprising a housing (1) in which a rotating shaft (2) is arranged, a plate (3) inserted on the shaft (2) and configured to oscillate about said shaft (2), two pumping pistons (4) in sliding contact, in the embodiment shown by means of spherical joints, with the plate (3),The image shows two pistons (4), although in the embodiment there are eleven, a drum (5) fixed to the shaft (2) so that it rotates with it, the drum (5) including a pumping cylinder (5.1) for each pumping piston (4), each pumping cylinder (5.1) configured such that the pumping piston (4) can slide in it during the rotation of the drum (5), as is known when the plate (3) has an angle of inclination other than 90° with respect to the longitudinal axis of the pumping pistons (4). The embodiment also shows a plate (6) disposed between the drum (5) and the housing (1) and around the shaft (2) so that it can rotate about said shaft (2), figures 1 and 3; The plate (6) comprises an inlet opening (6.1) configured for the passage of a fluid into the pump, which corresponds to an inlet nozzle (1.10) in the housing (1), figures 4 and 5, from the plane of figure 3 approaching the reader,and a discharge opening (6.2) configured for the passage of the fluid to the outside of the pump, which corresponds to a discharge nozzle (1.11) in the casing (1), figures 4 and 5, from the plane of figure 3 moving away from the reader, the inlet opening (6.1) is arranged on the plate (6) diametrically symmetric with respect to the discharge opening (6.2), figure 3, and the inlet nozzle (1.10) is arranged symmetrically with respect to the discharge nozzle (1.11), figures 4 and 5. In the configuration of figure 3, the inlet opening (6.1) is on the right of the figure and is composed of three lobes, the discharge opening (6.2) is on the left of the figure and is also composed of three lobes as it is diametrically symmetric; In Figures 4 and 5, the inlet nozzle (1.10) is on the left and the outlet nozzle (1.11) is on the right. As discussed above in the description of the invention,“Intake” and “drive” are terms used to differentiate elements, having that meaning in the first position and the opposite in the second position, positions described in that section and below. In the embodiment shown in Figure 3, the plate (6) has a protrusion (6.3); a first pin (7) is arranged in a first housing (1.1) of the casing (1), positioned transversely to the axis (2) and accessible from the outside of the casing (1); a second pin (8) is arranged in a second housing (1.2) of the casing (1), positioned transversely to the axis (2), accessible from the outside of the casing (1) and facing the first pin (7); such that the first pin (7) has a first length that contacts the protrusion (6.3) and the second pin (8) has a second length that contacts the protrusion (6.3), as mentioned above, with the plate (6) in a first position,The right side is for intake and the left side is for discharge. The pump rotates clockwise with respect to the front view in Figure 3, as indicated by the curved arrow. By changing the positions of the first pin (7) and the second pin (8), the plate (6) rotates to a second position, and the pump is configured to operate in the opposite direction of rotation, rotating counterclockwise with respect to the front view in Figure 2. A detail of the embodiment shown in Figure 1 is that it also includes an accumulation piston (9) and a return piston (10), both in sliding contact with the plate (3), in the embodiment shown by means of spherical joints.arranged diametrically opposite each other and parallel to the outside of the pumping pistons (4); the housing (1) includes an accumulation cylinder (1.3) configured such that the accumulation piston (9) can slide therein; the housing (1) also includes a return cylinder (1.4) configured such that the return piston (10) can slide therein. Continuing with the details of the embodiment, as shown in Figure 5, the housing (1) includes a first conduit (1.5) between the return cylinder (1.4) and a regulating valve (11); the housing (1) also includes a second conduit (1.6), L-shaped in the embodiment of Figures 1 and 3, which connects the accumulation cylinder (1.3) and the regulating valve (11); The housing (1) also includes a third conduit (1.7), figure 5, transverse to the first conduit (1.5) configuring a first branch (1.71) and a second branch (1.72) of the third conduit (1.7),Both being separated by the first conduit (1.5); a fourth conduit (1.8) parallel to the axis (2) - or approximately parallel -, Figure 5, connects the first branch (1.71) with the inlet nozzle (1.10); a fifth conduit (1.9) parallel to the axis (2) - or approximately parallel -, Figure 5, connects the second branch (1.72) with the discharge nozzle (1.11). The fourth conduit (1.8) and the fifth conduit (1.9) do not connect with the inlet nozzle (1.10) and the discharge nozzle (1.11) in the plane of Figure 5, as can be seen, but are transverse, approximately perpendicular to said plane to reach said nozzles in a different plane, further into the pump, as in the plane of Figure 4; Figure 5 is shown in a plane passing through the first plug (1.73) and the second plug (1.74), which are located almost at the end of the pump where the fluid inlet and outlet are. Continuing with the explanation of the detail, the housing (1) includes a sixth conduit (1.12),Figure 4, which connects the intake nozzle (1.10) with the first housing (1.1), a connection which takes place by the interference of both; a seventh conduit (1.13), Figure 4, connects the discharge nozzle (1.11), with the second housing (1.2), a connection which takes place by the interference of both; the third conduit (1.7) includes a distribution valve (12), a three-way ball valve in the embodiment shown, so that the plate (6) and the distribution valve (12) are in a first position, as shown in Figures 3 and 5, when the first pin (7) is in the first housing (1.1) and the second pin (8) is in the second housing (1.2), and a second position, not shown, when the first pin (7) is in the second housing (1.2) and the second pin (8) is in the first housing (1.1). The first position configures the pump so that it allows the passage of the driving fluid from the driving nozzle (1.11),to the second housing (1.2), to the seventh passage (1.13), to the fifth passage (1.9), to the second branch (1.72), to the first passage (1.5) and from there to the return cylinder (1.4) and the regulating valve (11); in the second position it allows the passage of the driving fluid from the inlet nozzle (1.10), which acts as the driving nozzle in this second position, to the first housing (1.1), to the sixth passage (1.12), to the fourth passage (1.8), to the first branch (1.71), to the first passage (1.5) and from there to the return cylinder (1.4) and the regulating valve (11). This ensures that there is always pressure for the return piston (10) and for the regulating valve (11) which regulates the pressure to the accumulating piston (9) in order to move the plate (3) and vary the pump flow rate. There is also always a fluid drain to collect leaks, an internal drain as the fluid returns through the inside of the pump, according to the exposed conduits.to the first housing (1.1) or the second housing (1.2) depending on the first or second position, respectively. For example, in the first position, the drain fluid will flow from inside the pump to the first housing (1.1) and then, following the shortest path to the intake, which is through the sixth passage (1.12) and from there to the intake nozzle (1.10) to be drawn into the cylinders through the valve plate (6). In the second position, the path is: second housing (1.2), seventh passage (1.13), discharge nozzle (1.11). The two positions described, first and second, correspond to both rotations of the pump. Thus, the embodiment shown corresponds to the rotation mentioned above and indicated in Figure 3. If the first pin (7) and the second pin (8) are interchanged, the valve plate (6) rotates due to their different lengths, and the pump is configured to rotate in the opposite direction. In both cases,The return piston (10) and the regulating valve (11) receive fluid at constant pressure. This regulating valve (11) controls the pressure supplied to the accumulating piston (9) so that it is differential with respect to the pressure received by the return piston (10), thus changing the inclination of the plate (3). Internal drainage is ensured by the first housing (1.1) or the second housing (1.2) acting as fluid collection chambers. With a simple configuration, without complex moving mechanical parts, the pump is designed to rotate in either direction and to regulate its flow rate, as well as to have internal fluid drainage without the need for pipes to an external reservoir. One option, shown in Figure 3,The diameter of the first pin (7) is smaller than the diameter of the first housing (1.1) and the diameter of the second housing (1.2). The diameter of the second pin (8) is such that it partially fits within the diameter of the first housing (1.1) and the diameter of the second housing (1.2). This maintains a simple configuration for closing either the first housing (1.1) or the second housing (1.2), isolating the communication between the discharge nozzle (1.10) and the pump interior via the conduits, as described above. In the first position, the discharge nozzle (1.10) is closed; in the second position, the inlet nozzle (1.10) is isolated from the pump interior. Specifically, the second pin (8) may include an O-ring (8.1), as shown in Figure 3, which is an inexpensive and readily available component.so that it can close the first housing (1.1) and the second housing (1.2) in the portion where it fits. In the embodiment shown, the first pin (7) is also a plug for the conduit in which it is located, the first housing (1.1), Figure 3, just as the second pin (8) acts as a plug for the second housing (1.2). Whereas, in Figure 5, a first plug (1.73) is provided for the first branch (1.71), and a second plug (1.74) for the second branch (1.72); in Figure 4, a third plug (1.14) is provided for the sixth conduit (1.12), and a fourth plug (1.15) for the seventh conduit (1.13). This is a mere embodiment; any other is possible, assuming that the conduits in the pump are closed as is known to those skilled in the art, except for the main intake and discharge conduits.Otherwise, it would be a pump with open conduits, unable to generate pressure. It should be noted here that Figure 3 and Figures 4 and 5 are cross-sections in opposite directions. Figure 3 shows the elements in a mirror image of Figures 4 and 5, which should not lead to confusion. The intake section, which in Figure 3 is on the right and the discharge section on the left, is reversed in Figures 4 and 5, as described above, with the intake section on the left and the discharge section on the right.

Claims

CLAIMS 1.–A variable displacement, reversible hydraulic pump comprising a housing (1) in which a rotating shaft (2) is disposed, a plate (3) inserted on the shaft (2) and configured to be able to oscillate about said shaft (2), two pumping pistons (4) in sliding contact with the plate (3), a drum (5) fixed to the shaft (2) so as to rotate with it, the drum (5) including a pumping cylinder (5.1) for each pumping piston (4), each pumping cylinder (5.1) configured such that the pumping piston (4) can slide therein during the rotation of the drum (5), a plate (6) disposed between the drum (5) and the housing (1) and around the shaft (2) so as to be able to rotate about said shaft (2), the plate (6) comprising an inlet opening (6.1) configured for the passage of a fluid into the interior of the pump corresponding to an inlet nozzle (1.10) in the housing (1), and a drive opening (6.2) configured for the passage of the fluid to the outside of the pump, which corresponds to a discharge nozzle (1.11) in the housing (1), the inlet opening (6.1) is arranged in the plate (6) diametrically symmetric with respect to the discharge opening (6.2), and the inlet nozzle (1.10) is arranged symmetrically with respect to the discharge nozzle (1.11), characterized in that the plate (6) has a protrusion (6.3); a first pin (7) is arranged in a first housing (1.1) of the housing (1), arranged transversely to the axis (2) and accessible from the outside of the housing (1); a second pin (8) is arranged in a second housing (1.2) of the housing (1), arranged transversely to the axis (2), accessible from the outside of the housing (1) and facing the first pin. (7); such that the first pin (7) has a first length such that it contacts the projection (6.3) and the second pin (8) has a second length such that it contacts the projection (6.3), leaving the plate (6) in a first position; by changing the positions between the first pin (7) and the second pin (8), the plate (6) rotates, remaining in a second position, and the pump is configured to operate in the opposite direction of rotation. 2.-Pump according to claim 1 further comprising an accumulation piston (9) and a return piston (10), both in sliding contact with the plate (3), arranged diametrically opposite each other and parallel to the outside of the pumping pistons (4); the housing (1) includes an accumulation cylinder (1.3) configured such that the accumulation piston (9) can slide therein; the housing (1) includes a return cylinder (1.4) configured so that the return piston (10) can slide therein; the housing (1) includes a first conduit (1.5) between the return cylinder (1.4) and a regulating valve (11); the housing (1) includes a second conduit (1.6) connecting the accumulation cylinder (1.3) and the regulating valve (11); the housing (1) includes a third conduit (1.7) transverse to the first conduit (1.5) configuring a first branch (1.71) and a second branch (1.72) of the third conduit (1.7), both being separated by the first conduit (1.5); a fourth conduit (1.8) parallel to the axis (2) connects the first branch (1.71) to the inlet nozzle (1.10); a fifth conduit (1.9) parallel to the axis (2) connects the second branch (1.72) to the outlet nozzle (1.11); a sixth conduit (1.12) connects the intake nozzle (1.10) to the first housing (1.1); a seventh conduit (1.13) connects the. drive nozzle (1.11) with the second housing (1.2); the third conduit (1.7) includes a distribution valve (12), such that the plate (6) and the distribution valve (12) are in a first position when the first pin (7) is in the first housing (1.1) and the second pin (8) is in the second housing (1.2), and a second position when the first pin (7) is in the second housing (1.2) and the second pin (8) is in the first housing (1.1); such that the first position allows the passage of the drive fluid from the drive nozzle (1.11), to the second housing (1.2), to the seventh conduit (1.13), to the fifth conduit (1.9), to the second branch (1.72), to the first conduit (1.5) and from there to the return cylinder (1.4) and the regulating valve (11); In the second position it allows the passage of the propulsion fluid from the intake nozzle (1.10), to the first housing (1.1), to the sixth conduit (1.12), to the fourth conduit (1.8), to the first branch (1.71), to the first conduit (1.5) and from there to the return cylinder (1.4) and the regulating valve (11). 3.-Pump according to claim 2 wherein the diameter of the first pin (7) is smaller than the diameter of the first housing (1.1) and the diameter of the second housing (1.2); the diameter of the second pin (8) is such that it partially fits into the diameter of the first housing (1.1) and the diameter of the second housing (1.2). 4.-Pump according to claim 3 wherein the second pin (8) includes an O-ring (8.1) so that it can seal the first housing (1.1) and the second housing (1.2) in the portion thereof. in which it is adjusted.

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