Volumetric variable displacement machine

Abstract

A volumetric variable displacement machine interacting with an operating fluid, the machine being a motor with an axial piston or a pump with an axial piston, and comprising: i) a device (2) interacting with the operating fluid; ii) a housing (3) containing means (2) that interact with the operating fluid; iii) actuating means (4) for adjusting the displacement of the machine; iv) a control unit (5) for controlling the actuating means (4); v) a detection sensor (6) for detecting a parameter associated with an employed displacement of the machine and operatively connected to the control unit (5); vi) a protective housing (7) for protecting the control unit (5), the protective housing (7) being integrated into the accommodating housing (3) or physically constrained to the accommodating housing (3). And the detection sensor (6) is placed in the protective shell (7).

Description

Technical Field

[0001] The present invention relates to a positive displacement machine that interacts with an operating fluid. Background Art

[0002] As is known, variable displacement piston pumps better adapt their operation to different applications or uses. In order to vary the displacement, the inclination of a plate connected to one end of the piston relative to the axis of rotation can be acted upon.

[0003] These pumps are integrated into systems that allow the displacement to be determined instantly. For this purpose, angle sensors are used on the machine body.

[0004] This angle sensor sends a signal to a remote control unit which, depending on the information received, sends specific commands to the valves that allow the plate to be adjusted fluidically.

[0005] The object of the present invention is to propose a volumetric variable displacement machine that allows optimized wiring and a higher assembly speed. Summary of the invention

[0006] The technical task and the specified aims are substantially achieved by a volumetric variable displacement machine comprising the technical characteristics disclosed in one or more of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Further characteristics and advantages of the invention will become more apparent from the following indicative and therefore non-limiting description of a volumetric variable displacement machine as shown in the accompanying drawings, in which:

[0008] - Figure 1 shows a perspective view of a volumetric machine according to the invention;

[0009] - Figure 2 Shows Figure 1 a machine with some parts removed to better highlight others;

[0010] - Figure 3 Shows Figure 1 A cross-sectional view of a machine;

[0011] - Figure 4 Shows Figure 3 Zoomed in details. DETAILED DESCRIPTION

[0012] In the attached drawings, reference numeral 1 denotes a volumetric variable displacement machine interacting with an operating fluid. Typically, the operating fluid is an incompressible fluid, such as oil. Machine 1 is a motor with an axial piston or a pump with an axial piston. A pump with an axial piston has a plurality of pistons that can move forward and backward in a direction parallel to its axis of rotation. The same is true for a motor with an axial piston. In the case of a motor, the energy of the operating fluid is used to set in motion an element (usually a shaft) so that the mechanical energy obtained can be utilized; in the case of a pump, the energy is used to set in motion an element (usually a shaft) that allows a pressure jump of the operating fluid.

[0013] The machine 1 comprises a device 2 for interacting with an operating fluid.

[0014] The machine 1 further comprises a housing 3 containing the means 2 for interacting with the operating fluid. Suitably, the housing 3 may be defined in the art as a "box" or a "machine body" (and may be a single body or an assembly of multiple parts).

[0015] Suitably, the pump with an axial piston or the motor with an axial piston comprises, in turn:

[0016] - a plurality of pistons 21, which are movable forwards and backwards along a common movement direction and are rotatable about a rotation axis 230 parallel to the movement direction (suitably, the pistons 21 are movable forwards and backwards in the corresponding chambers 22; suitably, the rotation axis 230 is a common rotation axis of the pistons 21);

[0017] A structure 23 having a variable inclination relative to the axis of rotation 230 for adjusting the stroke of the piston 21 and therefore the displacement of the machine 1 .

[0018] A change in the inclination of the structure 23 relative to the axis of rotation 230 results in a change in displacement (in a particular case, reference is made to a change in inclination relative to the axis of rotation 230, but this would be equivalent to reference to a change in inclination relative to an imaginary plane orthogonal to said axis 230 or perpendicular to said imaginary plane). Typically, a change in the inclination of the structure 23 relative to the axis 230 provides a rotation of the structure 23 about an imaginary straight line 232. Said straight line 232 suitably extends in a direction orthogonal to the direction of the axis of rotation 230 (suitably, the imaginary straight line 232 is orthogonal to the axis of rotation 230). An increase or decrease in the inclination of the structure 23 actually results in an increase or decrease in the stroke of the piston and therefore in an increase or decrease in the displacement of the pump (hence the correlation between the angle of inclination of the structure 23 and the displacement). In the case where the machine 1 is a motor, the rotation of the piston 21 about the axis of rotation 230 will in turn drag the chamber 22 in rotation about the axis of rotation 230. Advantageously, the chamber 22 is integrated in the body, so that the body is dragged in rotation about the axis of rotation 230. In the case where the machine 1 is a pump, the rotation of the chamber 22 will drag the piston 21 in rotation about the axis 230. The structure 23 is called a plate or an oscillating plate in technical terms. If the plate extends orthogonally to the axis of rotation 230, the displacement is zero. Increasing the inclination relative to the axis 230 increases the displacement.

[0019] The machine 1 comprises an actuating device 4 for adjusting the displacement of the machine. The actuating device 4 acts on said structure 23 with variable inclination to adjust the displacement of the machine 1.

[0020] For example, the actuator 4 may include a regulator, such as an electric proportional regulator or a solenoid valve or other device (such as an electric motor) that (fluidically or otherwise) regulates the inclination of the structure 23 relative to the rotation axis 230.

[0021] Suitably, a solenoid valve refers to an electrically operated valve that changes the flow rate according to an electrical signal. An electric proportional regulator is a set of components that can adjust the displacement of a pump, which can also include a solenoid valve. An electric proportional regulator can act on the displacement to make a regulation proportional to the electrical signal.

[0022] For example, the piston 21 is indirectly associated with the structure 23 via a piston guide plate, which is rotatable together with the piston 21 about the rotation axis 230. As a non-limiting example, the piston guide plate may be urged towards the structure 23 by a spring.

[0023] The machine 1 comprises a control unit 5 for controlling the actuating means 4. The control unit 5 sends, for example, electrical signals to the actuating means 4, which, for example, fluidically adjust the inclination of the structure 23 relative to the axis of rotation 230. The actuating means 4 thus allow the displacement of the machine 1 to be adjusted by receiving electrical signals from the control unit 5.

[0024] An electric proportional regulator or solenoid valve or other device capable of adjusting the inclination of the structure 23 relative to the axis 230 can perform different functions (e.g. regulating the pressure, the flow rate, the absorbed torque, ...) by regulating the displacement of the pump in a proportional or discrete manner. In the same machine 1, there can be more regulators (or solenoid valves) performing different functions.

[0025] The control unit 5 advantageously comprises a first connector 51 and a second connector 52. The control unit 5 is connected to a controller (eg to an electric proportional controller) via the first connector 51, but the control unit 5 may also be connected directly to the output cable (without connectors).

[0026] A second connector 52 connects the control unit 5 of the pump to an additional control unit, usually external to the machine 1, for reading or sending data. In theory, such a connection may also not exist (unprivileged solution).

[0027] The first connector 51 and / or the second connector 52 may also control other electric proportional regulators and / or other valves on the machine 1 and / or general electrical components outside the machine 1 , and / or read signals from other sensors.

[0028] The control unit 5 may comprise an electronic board 50. Advantageously, the control unit 5 and / or the board 50 may be assembled in two possible ways (e.g. by positioning both the first connector 51 and the second connector 52 upwards or both downwards or one upwards and the other downwards). Suitably, the sensor 6 is associated with the board 50. In particular, the sensor 6 (i.e. the sensing element) is immovably connected to the board 50. Suitably, the sensor 6 is located on the surface of the board 50 (e.g. the board 50 is directly connected). Suitably, the sensor 6 is welded to the board 50.

[0029] The machine 1 comprises a sensor 6 for detecting a parameter associated with the displacement adopted by the machine 1. As better explained below, this parameter is for example the inclination of the structure 23 relative to the axis of rotation 230. This sensor 6 is operatively connected to the control unit 5. Thus, the sensor 6 can electrically interact with the control unit 5.

[0030] Advantageously, the detection sensor 6 comprises or is an angle detection sensor which detects a change in the inclination of the structure 23 relative to the rotation axis 230 .

[0031] Preferably, the angle sensor is a Hall effect sensor. The angle sensor interacts remotely with a magnet 231 that is firmly constrained to the structure 23 to include the degree of inclination of the structure 23 relative to the rotation axis 230. Based on the relative position between the magnet and the angle sensor (in particular the Hall effect sensor), the angle sensor is able to determine the inclination of the structure 23 relative to the rotation axis 230. This information indicates the displacement at a given time. The magnet 231 is appropriately placed on a straight line 232, where the inclination of the structure 23 can vary around the straight line 232. In this way, the angle of the magnetic field of the magnet 231 can be precisely tilted with the angle of the structure 23. Suitably, the angle sensor is placed on a straight line 232, where the inclination of the structure 23 can vary around the straight line 232. More generally, the protective housing 7 is located on a straight line 232, where the structure 23 can be tilted around the straight line 232 to change the displacement.

[0032] Conveniently, the magnet 231 is firmly constrained to the structure 23 by means of a magnet holder 233 (and one or more interposing elements), but the magnet 231 may also be positioned directly on the structure 23, for example if the magnet 231 has a support for the magnet 231 made in one piece.

[0033] The machine 1 comprises a protective housing 7 of the control unit 5. Such a protective housing 7 is visible, for example, outside the containing housing 3. Said protective housing 7 is physically constrained to said containing housing 3. In particular, the protective housing 7 is flange-connected to the containing housing 3. Thus, the protective housing 7 is connected to the containing housing 3 by a connector, for example a threaded connector.

[0034] In an alternative solution, the protective housing 7 can be integrated into the receiving housing 3 .

[0035] The detection sensor 6 is placed inside the protective housing 7. Suitably, the sensor 6 is located outside the containing housing 3.

[0036] Suitably, the protective shell 7 contributes to defining the containing shell 3. In practice, the protective shell 7 defines a plug for the containing shell 3 (in practice, the plug closes the opening of the protective shell 7).

[0037] The protective housing 7 also acts as a hydraulic seal for the fluid (usually oil) present in the containment housing 3. Typically, at least one gasket is therefore interposed between the housing 3 and the housing 7.

[0038] In particular, the protective housing 7 comprises two assembled half-shells 71, 72. One of such half-shells acts (cooperating with at least one gasket 73) as a plug for the opening of the housing 3. The at least one gasket 73 surrounds the mouth of the housing 3 closed by the housing 7.

[0039] At least a portion of the protective housing 7 placed at the detection sensor 6 is not ferromagnetic, suitably it is paramagnetic or diamagnetic. For example, the housing 7 is made of aluminum. Suitably, the entire protective housing 7 is not ferromagnetic, but suitably paramagnetic or diamagnetic. The use of one or more non-ferromagnetic elements allows a more accurate measurement of the position of the structure 23 (usually determined by a Hall effect sensor).

[0040] Advantageously, in the case of a Hall Effect sensor, the sensor 6 is less than 10 millimeters from a magnet 231 firmly constrained to the structure 23 and with which it interacts to have a parameter related to the displacement of the machine 1. In fact, reducing this distance increases the number of magnetic field lines generated by the magnet 231 that strike the sensor 6. The measurement is therefore more precise and reliable. Furthermore, reducing this distance also improves the reliability of the measurement, also considering the possibility of having fewer disturbances.

[0041] Suitably, the area inside the housing 3 and the detection sensor 6 are physically separated by a wall 37 integrated in the protective housing 7 (but the wall 37 can also be a wall integrated in the housing 3; in this case, the gasket 73 will not be present and the protective housing 7 will not act as a plug). Or in any case, the wall 37 is physically between the internal area of ​​the housing 3 and the sensor 6.

[0042] Said wall 37 has a thickness which is thinned relative to the surrounding area at the detection sensor 6. The purpose of this is to minimize any disturbance in the measurement. In fact, as already explained, in the case of a Hall Effect sensor, it is important to reduce as much as possible the distance between the sensor and the magnet firmly constrained to the structure 23.

[0043] The present invention achieves important advantages.

[0044] Firstly, the invention allows to optimize the wiring. This is achieved by positioning the detection sensor for detecting the displacement parameter inside the protective housing 7 of the control unit and by positioning the housing 7 close to the housing 3 (machine body). Furthermore, the positioning of the protective housing 7 close to the machine body is advantageous in that it occurs precisely in a position that facilitates and optimizes the detection of the parameter associated with the inclination of the structure 23 relative to the axis of rotation 230.

[0045] As envisioned, the present invention is susceptible to multiple improvements and variations, all of which fall within the scope of the inventive concept thus characterized. In addition, all details can be replaced by other equivalent technical elements. In practice, all materials and sizes used can be any materials and sizes as required.

Claims

1. A volumetric variable displacement machine interacting with an operating fluid, the machine being a motor with an axial piston or a pump with an axial piston and comprising: i) means (2) for interacting with the operating fluid; ii) a containing shell (3), wherein the containing shell (3) contains the device (2) that interacts with the operating fluid; iii) an actuating device (4) for adjusting the displacement of the machine; iv) a control unit (5), the control unit (5) being used to control the actuating device (4); v) a detection sensor (6) for detecting a parameter associated with the displacement adopted by the machine and operatively connected to the control unit (5); It is characterized in that the machine comprises a protective shell (7) for protecting the control unit (5), wherein the protective shell (7) is integrated into the accommodating shell (3) or physically constrained on the accommodating shell (3); and the detection sensor (6) is placed inside the protective shell (7).

2. The machine according to claim 1, characterized in that The axial piston motor or the axial piston pump comprises in sequence: - a plurality of pistons (21) which are movable forwards and backwards along a common direction of movement and are rotatable about a rotation axis (230) parallel to the direction of movement; - a structure (23) with a variable inclination relative to the axis of rotation (230) for adjusting the stroke of the piston and thus the displacement of the machine; the actuating device (4) acts on the structure (23) with a variable inclination to adjust the displacement of the machine (1).

3. The machine according to claim 2, characterized in that The protective housing (7) and / or the sensor (6) are intersected by a straight line (232), and the structure (23) with a variable inclination is inclined around the straight line (232) to change the displacement.

4. The machine according to claim 2 or 3, characterized in that The detection sensor (6) comprises an angle sensor or an angle sensor, and the angle sensor detects the change of the inclination of the structure (23) with variable inclination relative to the rotation axis (230).

5. The machine according to claim 4, characterized in that The angle sensor is a Hall Effect sensor and interacts remotely with a magnet (231) that is securely constrained to the structure (23) with variable inclination to include the degree of inclination of the structure (23) with variable inclination relative to the rotation axis (230).

6. The machine according to claim 5, characterized in that The detection sensor (6) is less than 10 millimeters away from the magnet (231).

7. Machine according to any one of the preceding claims, characterised in that A portion of the accommodating housing (3) placed at the detection sensor (6) and / or the protective housing (7) is not ferromagnetic.

8. Machine according to any one of the preceding claims, characterised in that The protective housing (7) is outside the accommodating housing (3) and is flange-connected thereto.

9. Machine according to any of the preceding claims, characterised in that A wall (37) integrated in the containment housing (3) or integrated in the protective housing (7) physically separates: - an area defined by said containment housing (3); and - said detection sensor (6).

10. The machine according to claim 9, characterized in that The wall (37) has a thickness that is thinned at the detection sensor (6) relative to the surrounding area.

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