HYDRAULIC UNIT WITH COMBINED PNEUMATIC/SERVOMOTOR ACTION AND RELATED USE

Abstract

The present patent of invention relates to a hydraulic unit (U) with a pneumatic cylinder (15) that works jointly with a servomotor (M), together with a ball screw (29) to together move a hydraulic piston pump (8), made up of a hydraulic plunger (7), with related sealing elements to prevent oil leaks, noise, metal-on-metal attrition and loss of efficiency, that is moved upwards and downwards using a ball screw (29) and a pneumatic cylinder (15), jointly with a servomotor (M) which, when moved, pushes the pressurized oil outwards while filling the opposite hydraulic chamber with an oil suction movement, the pumped oil entering a hydraulic pressure accumulator (25), where it remains idle to be used when required and being supplied by the up/down movement of the piston, generating continuous pumping, which is automatically stopped when the hydraulic pressure accumulator (25) is full and has reached the predetermined hydraulic pressure. With regard to the field of application, the invention is intended to be used to move hydraulic actuators in a variety of different machines and equipment.

Claims

1-10. (canceled)

11. A hydraulic unit with combined pneumatic/servomotor action characterized by comprising: a servomotor; a pneumatic cylinder comprising a pneumatic plunger, a lower pneumatic chamber, an upper pneumatic chamber, a pneumatic directional valve and a rod; a ball screw supported on rollers mounted on a bearing; a hydraulic pump comprising a hydraulic sleeve, a hydraulic plunger, and an upper hydraulic chamber; an oil reservoir; an upper check valve; an upper sensor; a hydraulic pressure accumulator; and a pressure sensor; wherein the unit is activated by the servomotor jointly with the pneumatic cylinder working in line on the same axial axis, with the objective of combining forces to increase the hydraulic pressure generated.

12. The hydraulic unit according to claim 11, characterized in that the ball screw is coupled directly on the rod of the pneumatic cylinder so as together to displace the hydraulic plunger, situated on the hydraulic sleeve of the hydraulic pump.

13. The hydraulic unit according to claim 1, characterized in that the pneumatic cylinder works immersed in oil from the oil reservoir, using the low temperature generated by the expansion of the compressed air in the pneumatic cylinder to automatically cool the oil contained in the oil reservoir.

14. The hydraulic unit according to claim 1, characterized in that the upper sensor is activated when the pneumatic plunger arrives at the end of the upward stroke, said sensor electronically controlling the inversion of the turning direction of the servomotor, thus causing the inversion in the turning direction of the ball screw, which thereafter turns counter-clockwise.

15. The hydraulic unit according to claim 1, characterized in that the servomotor (M) electronically monitors the need to replace oil from the pressure accumulator.

16. The hydraulic unit according to claim 1, characterized in that the hydraulic plunger contains sealing elements to eliminate oil leaks and loss of efficiency.

17. The hydraulic unit, according to claim 1, characterized by being for moving hydraulic actuators in machines or equipment.

18. The hydraulic unit according to claim 7, characterized in that up to 90% of the volume of oil from the reservoir is reduced.

19. The hydraulic unit according to claim 8, characterized by generating savings of up to 90% in electric energy.

20. The hydraulic unit according to claim 7, characterized by dissipating the heat of the hydraulic oil.

Description

DESCRIPTION OF THE DRAWINGS

[0028] The invention will now be described in terms of an embodiment, and for improved understanding, references will be made to the accompanying drawings, represented as follows:

[0029] FIG. 1: Sectional view of the complete assembly.

[0030] FIG. 2: Enlarged detail of the passage of the oil from the upper hydraulic chamber to the lower hydraulic chamber.

DETAILED TECHNICAL DESCRIPTION OF THE INVENTION

[0031] The COMBINED PNEUMATIC/SERVOMOTOR ACTION HYDRAULIC UNIT comprises a pneumatic cylinder (15) that has a pneumatic plunger (12), separating the lower pneumatic chamber (14) from the upper pneumatic chamber (18), where the rod (23) of the pneumatic cylinder (15) is fixed, which is directly linked to a hydraulic plunger (7) which is located inside the hydraulic sleeve (6) of the hydraulic pump (8), acting as a piston of the hydraulic pump (8), and on the other face of this hydraulic plunger (7), the rod (23) protrudes out of the upper hydraulic chamber (31) to receive the bolt of the ball screw (29), which will receive torque from the servomotor (M) to turn clockwise and counter-clockwise, with the objective of displacing the hydraulic plunger (7) upward and downward, performing the oil pumping process. The ball screw (29) is supported on rollers (2), which sustain radial and axial loads, and are mounted on a bearing (3) to give greater sturdiness to the system.

[0032] Working begins by powering the system, which feeds the servomotor (M) and, consequently, releases compressed air to feed the pneumatic directional valve (11). Therefore, when the servomotor (M) is turning clockwise, it will be pulling the hydraulic plunger (7) upwards and, at the same time, the pneumatic directional valve (11) will be directing the compressed air to the lower pneumatic chamber (14), combining the pneumatic force with the force generated by the torque on the ball screw (29), thereby increasing the force that is being applied on the volume of oil that is stored in the upper hydraulic chamber (31), which begins to be displaced, passing through the hole (27) of the upper hydraulic chamber (31), forcing the opening of the upper check valve (24) and being led to the hydraulic pressure accumulator (25), where it will remain idle until it is used. The upper check valve (24) also has an outlet pressure line (26) and a hole (28) of the pressure outlet.

[0033] In the same upward movement, while the oil is being pumped into the pressure accumulator (25), the hydraulic plunger (7) begins to draw oil from the oil reservoir (16), which passes through the suction filter (17) going through the low oil suction line (19) and forcing the opening of the check valve (22), reaching the lower hydraulic chamber (9), where it will continue being filled until the pneumatic plunger (12) reaches the end of the stroke. Next, when the pneumatic plunger (12) finally arrives at the end of the upward stroke, the upper sensor (4) is activated and electronically controls the inversion of the turning direction of the servomotor (M), the inversion of the turning direction of the ball screw (29) thus occurring, which thereafter turns counter-clockwise, and the same electronic command that was sent inverts the position of the pneumatic directional valve (11), which now directs the compressed air to the upper pneumatic chamber (18) by means of the hole (10) which, once filled, will begin the downward process of the hydraulic plunger (7), which will exert a force on the volume of oil which is in the lower hydraulic chamber (9), and will begin to displace this oil outwardly, as far as the hole (20) of the lower hydraulic chamber (9), initially forcing the opening of the check valve (22) and leading to the hydraulic pressure accumulator (25), where it should remain until it is used.

[0034] In the same downward movement, while the oil is being pumped inside the pressure accumulator (25), the hydraulic plunger (7) begins to draw oil from the oil reservoir (16) into the upper hydraulic chamber (31), passing first through the suction filter (17), going through the upper oil suction line (21) and forcing the opening of the upper check valve (24) and, finally, arriving at the upper hydraulic chamber (31), where it will continue to be filled until the pneumatic plunger (12) reaches the end of the lower stroke, keeping the oil in this upper hydraulic chamber (31) until the time when reversal of turning direction of the ball screw (29) occurs and inversion in the direction of the displacement of the pneumatic plunger (12).

[0035] This process of oil pumping enters into a continuous regime until the pressure accumulator (25) is totally filled and, when it is totally full, it attains working pressure, whereupon the pressure sensor (30) is activated and command the de-energization of the pneumatic directional valve (11), where it will remain in a center-closed position, and also commands the de-energization of the servomotor (M), interrupting the oil pumping process, which will resume when a hydraulic actuator begins to move. Now, when a hydraulic actuator of the machine that is using this invention begins to move, the pressure sensor (30) records a drop in pressure and immediately powers the servomotor (M) and the hydraulic directional valve (11), continuing the oil pumping process from the point where it stopped, keeping this same working regime for all the time necessary. The reason for stoppage of the servomotor (M), and also the stoppage of the displacement of the pneumatic cylinder (15), when it does not have a hydraulic actuator moving, is to prevent an oil venting process, which is the circulation of oil that is not being used to carry out work, returning to the oil reservoir (16). Therefore, this invention eliminates oil heating, eliminates vibration and noises generated by metal-on-metal attrition and the useful life of the system is extended for much longer periods.

[0036] Therefore, the hydraulic unit (U), comprising the pneumatic cylinder (15) interlinked to the servomotor (M), electronically monitors the need to replace the volume of oil from the pressure accumulator (25) and, its smart system enables pumping with just the quantity of oil that will be used, eliminating waste of electric energy and creating a better work environment.