EP4647609A1

EP4647609A1 - Control system for an actuator cylinder

Info

Publication number: EP4647609A1
Application number: EP25173468.7A
Authority: EP
Inventors: Pierre Luigi Zaccarelli; Antonio De Luca
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2024-05-06
Filing date: 2025-04-30
Publication date: 2025-11-12

Abstract

The present invention relates to a system for actuating an actuator cylinder (10) of a working machine, said actuator cylinder having a first and a second chamber (11, 12), a piston (13) separating said first chamber (11) from said second chamber (12) configured to move an element connected thereto, said system comprising a first supply duct (21) of said first chamber (11) of said cylinder (10), a second supply duct (22) of said second chamber (12) of said cylinder (10), wherein said first supply duct (21) and said second supply duct (22) are connectable to a distribution valve configured to control a supply operation and an exhaust operation of said first supply duct (21) and of said second supply duct (22), wherein along said first supply duct (21) and along said second supply duct (22) a first logic element (31) and a second logic element are positioned respectively (41), wherein said first logic element (31) and said second logic element (41) are positioned to regulate a flow of fluid along said first and said second supply conduits (21, 22), wherein each of said first and said second logic elements comprises an annular chamber (35, 45) and a spring chamber (34, 44), wherein said annular chamber (35, 45) is separated from said spring chamber (34, 44) by a piston (32, 42), wherein said piston comprises a slot (33, 43) configured to provide a hydraulic connection between said annular chamber and said spring chamber, wherein said annular chamber (35, 45) of said first and said second logic elements (31, 41) is configured to receive a fluid coming from said first and said second supply conduits (21, 22) respectively, wherein said spring chamber (34) of said first logic element (31) and wherein said spring chamber (44) of said second logic element (41) is hydraulically connected to a valve (50) which is configured to regulate a discharge of fluid flow coming from said spring chamber (34, 44) of said first and said second logic element (31, 41).

Description

TECHNICAL FIELD

The present invention relates to the field of a control system for controlling an actuator cylinder in a hydraulic application.

BACKGROUND

Control systems for hydraulic cylinders for the movement of booms of machines such as telescopic handlers and cranes have evolved more and more over the years and require an ever-increasing number of functions to be fulfilled. Firstly, they require high safety so that, in the event of a duct breakage, the system is able to control the actuator cylinder and stop it, preventing a possible fall of the load. Secondly, high system stability is required so as to ensure that the user can control the system without generating sudden jerks, which could cause a sense of discomfort in the user. Furthermore, last but not least, it is required that such systems are efficient in terms of consumption, so as to avoid waste such as bottlenecks, and that the costs of manufacturing such systems are contained in terms of prices.
From the state of the art, systems are known, such as the one shown in figure 1, which allow to alternately allow and prevent the actuation of the actuator cylinder. As shown, the actuator cylinder 10, like a common actuator cylinder of a working machine configured to move an element connected to it, comprises a first and a second chamber 11, 12, a piston 13 which separates said first chamber 11 from said second chamber 12. The system also comprises a first supply duct 21 of said first chamber 11 and a second supply duct 22 of said second chamber 12, wherein said first supply duct 21 and said second supply duct 22 are connectable to a distribution valve configured to control a supply operation and an unloading operation of said first supply duct 21 and said second supply duct 22.
As shown in the figure, along said first supply duct 21 and along said second supply duct 22 there are respectively positioned a first valve 98 and a second valve 99. Both valves are two-way, two-position electric valves. By means of this valve it is possible to regulate when this cylinder must be actuated (for example in the case where there are several cylinders placed one in parallel to the other). In fact, in the case in which it is decided to want to activate the cylinder 10, at least one of the valve 98 and the valve 99 will be activated so as to allow a flow of fluid entering towards the first or second chamber, so as to allow a movement of the cylinder 10.
The system shown in the figure is quite expensive as it requires the presence of two electric valves that must be operated independently of each other.
There are also individual valves on the market that allow you to perform the same function as shown in figure 1. However, these valves are particularly complex and extremely expensive. Furthermore, these valves are very specific and cannot be adapted to various conditions of use. Therefore, every time you want to slightly change the use, you need to substantially change the valve.
The aim of the present invention is first of all to make the assembly of the device as simple as possible. Secondly, it is particularly important to achieve a high flexibility of the system. Furthermore, a final aspect is to make the inspection process of the system as simple and straightforward as possible.

SUMMARY

The present invention relates to a method of regulating an actuator cylinder according to the features listed in claim 1. Such features include the presence of a (single, unique) valve connected to the spring-side chamber of said first and second logic element, so as to allow the use of a single valve for regulating the cylinder.
The proposed solution involves the use of components that can be easily assembled without requiring complex procedures. The proposed version of the device can also be customized to meet various needs without having to change the external dimensions. It is possible to adapt the device for different volumes and differential pressure (deltaP) requirements according to specific needs. The proposed solution also allows total flexibility in the intervention and customization of the individual connections, independently from each other. This means that it is possible to adjust and modify these connections separately without affecting the other functionalities of the device. Finally, the proposed solution aims to simplify this process, allowing easy verification of the connections and components without requiring complex procedures or specialized tools.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will be described with reference to the attached figures in which the same numbers and/or reference signs indicate the same parts and/or similar and/or corresponding parts of the system.

Figure 1 shows a hydraulic circuit diagram of a state-of-the-art control system for an actuator cylinder;
Figure 2 shows a hydraulic circuit diagram of a control system for an actuator cylinder according to an embodiment of the present invention;

DETAILED DESCRIPTION

Hereinafter, the present invention is described with reference to particular embodiments, as illustrated in the accompanying drawings. However, the present invention is not limited to the particular embodiments described in the following detailed description and depicted in the figures, but rather the embodiments described merely exemplify the various aspects of the present invention, the scope of which is defined by the claims. Further modifications and variations of the present invention will be apparent to one skilled in the art.
Figure 2 shows a diagram of a control system for an actuator cylinder 10 according to an embodiment of the present invention. The cylinder 10 is the same as shown in Figure 1 and therefore comprises a first and a second chamber 11, 12 and a piston 13 which separates said first chamber 11 from said second chamber 10. Said actuator cylinder is configured so as to allow the direct or indirect movement of an element, to which a load can be connected.
The first and second chambers 11, 12 are fed by the first and second supply ducts 20, 21 respectively.
As shown in the figure, along said first supply duct 21 and along said second supply duct 22 are positioned respectively a first logic element 31 and a second logic element 41. The first logic element 31 and the second logic element 41 are positioned so as to regulate respectively a flow of fluid along said first and said second supply duct 21, 22.
Each of said first and second logic elements comprises an annular chamber 35, 45 and a spring chamber 34, 44, wherein said annular chamber 35, 45 is separated from said spring chamber 34, 44 by means of a piston 32, 42. Said piston 30, 42 comprises a slot 33, 43 configured to provide a hydraulic connection between said annular chamber and said spring chamber.
As shown in the figure, the annular chamber 35, 45 of said first and said second logic element 31, 41 is configured to receive a fluid coming respectively from said first and said second supply conduit 21, 22. The spring chamber 34 of said first logic element 31 and the spring chamber 44 of said second logic element 41 are instead hydraulically connected to a valve 50 which is configured to regulate a discharge of fluid flow coming from said spring chamber 34, 44 of said first and said second logic element 31, 41.
The valve 50 shown in the figure is a two-way, two-position electric valve in which a first of said two ways represents a hydraulic connection with said spring chamber 34, 44 of said first and said second logic element 31, 41, in which a second of said two ways represents a hydraulic connection with said first and said second supply conduit 21, 22.
As shown in the figure, in fact, there is an exhaust duct of the spring-side chamber 34 on which are preferably positioned a restriction 51 and a one-way valve 52, configured so as to allow a flow coming from said spring chamber 34 to reach the valve 50 and to prevent a flow in the opposite direction. Similarly, there is an exhaust duct of the spring-side chamber 44 on which are preferably positioned a restriction 54 and a one-way valve 53, configured so as to allow a flow coming from said spring chamber 44 to reach the valve 50 and to prevent a flow in the opposite direction.
Furthermore, downstream of valve 50 there are two one-way valves 55, 56 configured to allow the flow of fluid arriving from spring chamber 34 and/or spring chamber 44 to be discharged towards the first supply duct (through valve 55) or towards the second supply duct (through valve 56) respectively.
In the following paragraphs, the operation of the previously described system will be briefly summarized, so as to increase clarity and better outline the advantages provided by the present invention.
As previously explained, the first and second supply lines 21, 22 can be individually pressurized, meaning that if the first supply line 21 is pressurized, the second supply line 22 will be connected to the exhaust line and vice versa.
The two logic elements essentially perform the function of restraint in the direction from A to D and from B to C since the pressure signal coming from A or B is transmitted via the slot 33 or the slot 43 to the spring chamber 34 or 44 and isolated from the other logic element thanks to the presence of the one-way valves 52 and 53. Furthermore, thanks to the difference in areas the logic element will allow a closed position of the supply ducts.
As long as the electric valve is in the rest position (in the position shown in figure 2), the pressure signal remains trapped and, thanks to the difference in areas present on the logic element, a resultant force is exerted which tends to keep the logic element closed.
By operating valve 50 and switching it to its second operating position (the one shown on the right of figure 2), in the event that the first supply duct 21 is pressurized, a vacuum is created in the spring chamber 34, as the pressure present in 34 will be conveyed through valve 50 towards the second supply duct so as to reach the exhaust. The resulting force in the logic element 31 will no longer be in favor of a closure, but will tend to increase the volume of the annular chamber 35, so as to allow the passage of fluid along the first supply duct from A to B.
As is clear from the figure, the operating principle is completely symmetrical; and it is valid both for the case in which the first supply duct 21 is pressurized and the second supply duct 22 is unloaded (described above), and for the case in which the first supply duct 21 is unloaded and the second supply duct 22 is pressurized. Therefore, to avoid unnecessary repetitions, the second case (second supply duct 22 under pressure) will not be described in detail.
The system described is also particularly advantageous in the case where there is a temperature increase in the first chamber 11 and/or in the second chamber 12.
In particular, following an increase in temperature inside said first chamber 11, which will clearly cause an increase in pressure in the first chamber 11, said annular chamber 35 of said first logic element 31 is configured to increase its volume so as to reduce the volume of said spring chamber 34 and to open a passage of fluid from said first chamber 11 towards said first supply duct 21. This is due to the fact that the pressure inside the first chamber 11 presses on the upper part of the piston 32, causing it to move downwards. As is clear, the decrease in the volume of said spring chamber 34 causes a movement of oil from said spring chamber 34 towards said annular chamber 35. The spring contained inside the spring chamber 34 will be calibrated so that up to a predetermined pressure difference between the spring chamber 34 and the first chamber 11 there is no opening of the logic element 31 (for example 1 bar). After the logical element 31 has opened the fluid passage, there will be a re-equilibrium of the pressures and the logical element 31 will tend to close again,
Furthermore, similarly to what has been described above regarding an increase in temperature of the fluid contained within the first chamber 11, following an increase in temperature within said second chamber 12, said logic element 41 is configured so that said annular chamber 45 increases its volume so as to reduce the volume of said spring chamber 44 and to open a passage of fluid from said second chamber 12 towards said second supply conduit 22, wherein the decrease in the volume of said spring chamber 44 causes a movement of oil from said spring chamber 44 towards said annular chamber 45.
While the present invention has been described with reference to the embodiments described above, it is clear to one skilled in the art that various modifications, variations and improvements of the present invention may be made in light of the teaching described above and within the scope of the appended claims, without departing from the subject matter and scope of the invention.
Finally, those areas which are considered to be known by those skilled in the art have not been described to avoid overshadowing the described invention in an unnecessarily manner.
Accordingly, the invention is not limited to the embodiments described above, but is only limited by the scope of the appended claims.

Claims

Actuation system of an actuator cylinder (10) of a working machine, said actuator cylinder having a first and a second chamber (11, 12), a piston (13) separating said first chamber (11) from said second chamber (12) configured so as to move an element connected thereto, said system comprising a first supply duct (21) of said first chamber (11) of said cylinder (10) and a second supply duct (22) of said second chamber (12) of said cylinder (10), wherein along said first supply duct (21) and along said second supply duct (22) are positioned respectively a first logic element (31) and a second logic element (41), wherein said first logic element (31) and said second logic element (41) are positioned so as to regulate a flow of fluid along said first and said second supply duct (21, 22), wherein each of said first and said second logic element comprises an annular chamber (35, 45) and a spring chamber (34, 44), wherein said annular chamber (35, 45) is separated from said spring chamber (34, 44) by a piston (32, 42), wherein said piston comprises a slot (33, 43) configured to provide a hydraulic connection between said annular chamber and said spring chamber, wherein said annular chamber (35, 45) of said first and said second logic element (31, 41) is configured to receive a fluid coming from said first and said second supply conduit (21, 22) respectively, wherein said spring chamber (34) of said first logic element (31) and wherein said spring chamber (44) of said second logic element (41) are hydraulically connected to a valve (50) which is configured to regulate a discharge of fluid flow coming from said spring chamber (34, 44) of said first and said second logical element (31, 41).
Actuation system of an actuator cylinder (10) according to claim 1, wherein said valve is a valve, preferably electric, with two ways and two positions, wherein a first of said two ways represents a hydraulic connection with said spring chamber (34, 44) of said first and said second logic element (31, 41), in a second of said two ways represents a hydraulic connection with said first and said second supply duct (21, 22).
Actuation system of an actuator cylinder (10) according to one of claims 1 to 2, wherein between said spring chamber (34) of said first logic element (31) and said valve (50) there is a first one-way valve (52) configured so as to allow a flow of fluid exiting from said spring chamber (34) and directed towards said valve (50) and to prevent flow in the opposite direction .
Actuation system of an actuator cylinder (10) according to one of claims 1 to 3, wherein between said spring chamber (44) of said second logic element (41) and said valve (50) there is a first one-way valve (53) configured so as to allow a flow of fluid exiting from said spring chamber (44) and directed towards said valve (50) and to prevent flow in the opposite direction.
Use of an actuator cylinder (10) actuation system according to one of claims 1 to 4, wherein following an increase in temperature inside said first chamber (11) said first logic element (31) is configured in such a way that said annular chamber (35) increases its volume so as to reduce the volume of said spring chamber (34) and to open a fluid passage from said first chamber (11) towards said first supply duct (21), wherein the decrease in the volume of said spring chamber (34) results in a displacement of oil from said spring chamber (34) towards said annular chamber (35).
Use of an actuator cylinder (10) actuation system according to one of claims 1 to 4, wherein following a rise in temperature inside said second chamber (12) said second logic element (41) is configured in such a way that said annular chamber (45) increases its volume so as to reduce the volume of said spring chamber (44) and to open a fluid passage from said second chamber (12) towards said second supply conduit (22), wherein the decrease in the volume of said spring chamber (44) results in a displacement of oil from said spring chamber (44) towards said annular chamber (45).