CN213655278U

CN213655278U - Control device and work apparatus

Info

Publication number: CN213655278U
Application number: CN202021467791.6U
Authority: CN
Inventors: C·斯托尔奇
Original assignee: Atlantic Fluid Tech SRL
Current assignee: Atlantic Fluid Tech SRL
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2021-07-09
Anticipated expiration: 2030-07-23

Abstract

The utility model relates to a controlling means and working equipment. A hydraulic control device includes: the valve comprises a valve body, a main piston axially movable in the valve body, an actuating member working at a first end of the main piston, a guide piston movable in a guide chamber inside the valve body, a guide stop member for controlling a passage of fluid in the guide chamber, a throttling member throttling towards the guide chamber, a one-way member arranged in parallel with the throttling member to allow flow from the guide chamber, an auxiliary guide piston between the main piston and the guide piston, wherein the auxiliary guide piston has a larger sealing diameter, resulting in a higher guide ratio.

Description

Control device and work apparatus

Technical Field

This solution relates to a control device, in particular to a device suitable for controlling a hydraulic actuator.

Background

In particular, but not exclusively, the present solution can be used in hydraulic control circuits with one or two directions of rotation, with a hydraulic motor of fixed or variable displacement, in particular for load lifting devices, such as winches. However, this solution may be used for controlling another type of hydraulic actuator, such as a hydraulic cylinder which can be used in particular in earth moving machines.

In particular, reference is made to a hydraulic control apparatus according to the preamble of claim 1, in which the throttling member improves the stability of the work, and the one-way member reduces the start-up delay caused by the throttling member. Patent publication EP 2631517 a1 discloses such a hydraulic control device.

However, such known control devices are not suitable in some cases, in particular when the valve device needs to be characterized by high calibration, i.e. for devices that can be configured to start the flow of working fluid at relatively high pressure by starting to open the stop-and, at the same time, have the ability to quickly reach the desired open position of the stop, in order to provide little resistance and thus reduce energy consumption. This can occur, for example, when the hydraulic actuator to be controlled is a hydraulic motor.

It is also desirable to further improve the operational stability of the prior art control devices.

SUMMERY OF THE UTILITY MODEL

It is an object of the present solution to overcome one or more of the above limitations and disadvantages of the prior art.

It is an object to provide an alternative hydraulic control device to the prior art.

The advantage is to allow the opening of the flow control stop to be initiated at relatively high pressures.

It is an advantage to provide a control device that can be moved from an initial position closing the hydraulic flow to a desired position opening the hydraulic flow in a relatively short time.

It is an advantage to provide a hydraulic control device with relatively low energy consumption.

The advantage is that a control device is created which achieves the desired valve opening position at a relatively low working pressure.

It is an advantage to provide a hydraulic control device having a relatively high operational stability.

The advantage is that it allows for an accurate, stable and reliable control of the hydraulic actuator, in particular the hydraulic motor.

The advantage is to allow control of the actuator, in particular even when the hydraulic fluid is more viscous (such as in winter), to prevent or reduce the delay between the instant the operator operates the guide and the instant the movement of the movable element of the actuator starts.

These objects and advantages, as well as others, are achieved by a control device according to one or more of the following aspects.

In an example, a hydraulic control apparatus includes: a valve body having an inner cavity and a guide opening; a main piston axially movable in the cavity of the valve body; an actuating member disposed at a first end of the master piston; a pilot piston movable within a pilot chamber inside the valve body; a guide stopper member for controlling a passage of fluid between the guide opening and the guide chamber; a throttling member for throttling between the guide opening and the guide chamber; a one-way member disposed in parallel with the throttle member; an auxiliary pilot piston, the first end of which faces the second end of the main piston, and the second end of which faces the first end of the pilot piston, wherein at least one sealing diameter of the auxiliary pilot piston is configured such that a configuration with a relatively high pilot ratio (for example a pilot ratio greater than 8: 1) is obtained.

In an example, a hydraulic control apparatus includes: a valve body; a main piston axially movable in the valve body; an actuating member operating at a first end of the master piston; a first sealing member for defining a first sealing area on the primary piston; a pilot piston movable within a pilot chamber inside the valve body; a guide stopper member for controlling a passage of the fluid in the guide chamber; a throttle member for throttling toward the guide chamber; a one-way member disposed in parallel with the throttle member; an auxiliary pilot piston disposed between the main piston and the pilot piston; a second sealing member for defining a second sealing area on the auxiliary pilot piston. The second sealing area is configured such that the guiding ratio is relatively high, for example a guiding ratio greater than 8: 1.

drawings

The embodiments may be better understood and implemented with reference to the accompanying drawings, which illustrate non-limiting examples of embodiments, in which:

fig. 1 is a longitudinal section of an example of a control device manufactured according to the present solution.

Fig. 2 is a longitudinal section of the device of fig. 1 according to a section orthogonal to the section of fig. 1.

Fig. 3 shows an enlarged detail of fig. 2.

Fig. 4 is a hydraulic diagram of a working device including the control apparatus of fig. 1.

Detailed Description

With reference to the preceding figures, the hydraulic control device is indicated as a whole with 1. The control device 1 may be used in particular for the control of a hydraulic actuator. The control device 1 may be used in particular in a hydraulic control circuit of a hydraulic motor M, for example a hydraulic motor used in a load lifting apparatus, such as a winch or the like. The hydraulic motor M may in particular have two directions of rotation, with fixed or variable displacement (displacement), etc.

The control device 1 may in particular comprise a valve body 2, the valve body 2 having at least one inner cavity for the passage of a fluid. The valve body 2 may in particular comprise a one-piece block or an assembly of several pieces as in the example shown. The valve body 2 may in particular comprise at least one first opening 3 or first gate for the passage of a working flow of hydraulic fluid (oil) and at least one second opening 4 or second gate for the passage of a working flow of hydraulic fluid.

The valve body 2 may in particular comprise at least one guide opening P or guide gate for a guide flow channel which can provide a guide signal as described below.

The opening or door arranged to the valve body 2 allows the control device 1 to be connected to a hydraulic circuit of a working apparatus (see fig. 4), such as in particular a load lifting apparatus (e.g. a winch).

In particular, the first opening 3 and the second opening 4 may be configured as passages for supplying a working flow of fluid required by the hydraulic actuator. In use, the first opening 3 may operate as a fluid inlet into the cavity of the valve body 2, for example for lifting a load, and the second opening 4 may operate as a fluid outlet from the cavity of the valve body 2, in turn for lowering a load.

The control device 1 may in particular comprise a main piston 5 axially movable in the cavity of the valve body 2. The main piston 5 is in particular movable in such a way as to be able to assume at least one closed position and at least one open position. In the closed position, the main piston 5 closes a passage section (passage section) for fluid passing through the chamber, which is arranged between the first opening 3 and the second opening 4. In the open position, the main piston 5 leaves the passage section open to allow flow. In particular, the passage section may be defined between a stop of the main piston 5 and an annular seat of the movable body C arranged in the cavity. In particular, a spring M may be provided to push (axially slide) the movable body C against the stop of the main piston 5.

The control device 1 may in particular comprise an actuating member 6 arranged at a first end of the main piston 5 to exert an axial force on the main piston 5. The actuating means 6 may in particular comprise elastic means configured for urging the main piston 5 towards the closed position. The elastic member may particularly comprise a spring.

The control device 1 may in particular comprise a first sealing member 7 arranged to the main piston 5 to define a first sealing area. The first sealing member 7 may in particular be arranged between the second opening 4 and a second end of the main piston 5 opposite to the first end. The first sealing part 7 may in particular comprise a sealing ring.

The control device 1 may comprise in particular a guide piston 8 which is movable in the valve body 2. The pilot piston 8 is in particular coaxially displaceable relative to the main piston 5. The pilot piston 8 is in particular movable inside a pilot chamber 9 obtained inside the valve body 2 and connected to the pilot opening P.

The control device 1 may in particular comprise a pilot stop member 10 configured to interact with (contact) the pilot piston 8 to control the passage of the pilot fluid. The channel is arranged between the guide opening P and the guide chamber 9.

The guide-stop member 10 may in particular be configured to selectively assume at least one open configuration, in which the guide-stop member 10 opens the above-mentioned channel for the guide fluid, and a closed configuration, in which the guide-stop member 10 closes the above-mentioned channel for the guide fluid. In this closed configuration, the pilot fluid can flow from the pilot opening P to the pilot chamber 9 (as better explained below) through the throttling member 11, in order to move the auxiliary piston, as better explained below.

The control device 1 may in particular comprise a throttling member 11, the throttling member 11 being configured to create a throttling (with a corresponding local pressure drop) between the pilot opening P and the pilot chamber 9.

The throttle member 11 may in particular comprise a closing element coupled with the valve body 2 by means of a threaded connection. The threaded connection defines a fluid-conducting channel, in particular a helically shaped channel, forming a choke.

In particular, the closing element may be provided with an adjustment member configured for adjusting the screwing of the same closing element, in order to thereby adjust the degree of throttling provided by the throttling member 11 (i.e. the degree of pressure drop in the thread).

In other examples, not shown, the choke may comprise other types of choked flow portions, such as a choked flow portion formed by a grain (grain), or a choked flow portion formed by a pair of coaxial elements (conical or cylindrical) partially inserted one into the other to define a size-adjustable passage, or a choked flow portion formed by other means.

The control device 1 may in particular comprise a unidirectional member 12 arranged in parallel with respect to the throttling member 11. The unidirectional component 12 may in particular, as in these examples, be configured to allow a flow of the pilot fluid from the pilot chamber 9 towards the pilot opening P. In other examples not shown, the unidirectional component 12 may be configured to allow flow in the opposite direction.

The non-return member 12 may in particular comprise a non-return valve arranged in the closing element of the throttle member 11.

The one-way component 12 allows rapid filling and emptying of the guide chamber 9. For example, when the operator starts the pilot operation, for example in order to lift a load, the main piston 5 must open the above-mentioned passage section arranged between the first opening 3 and the second opening 4, whereby the pilot chamber 9 must be filled quickly. For example, when the operator has finished the piloting operation, the main piston 5 will have to return to block again the passage section between the first opening 3 and the second opening 4, so that the piloting chamber 9 must be emptied rapidly. The unidirectional means 12 also allow the pilot fluid to flow safely towards the pilot opening P when the pressure in the pilot chamber 9 exceeds a certain value.

The control device 1 may comprise in particular an auxiliary pilot piston 13 which is movable in the valve body 2. The auxiliary pilot piston 13 can in particular be moved coaxially with respect to the main piston 5 and/or coaxially with respect to the pilot piston 8.

The auxiliary piston 13 can be arranged in particular axially between the main piston 5 and the guide piston 8.

The auxiliary piston 13 may in particular have a first end configured to face a second end of the main piston 5. The first end of the auxiliary piston 13 can interact in particular in contact with the second end of the main piston 5.

The auxiliary piston 13 may in particular have a second end (e.g. opposite to the first end) configured to face the first end of the guide piston 8. The guide chamber 9 may in particular be delimited at least partially by the above-mentioned second end of the auxiliary piston 13.

The control device 1 may in particular comprise a second sealing member 14 arranged to the auxiliary piston 13. The second sealing member 14 may particularly be configured to define a second sealing area. As in these examples, the second sealing member 14 may comprise a sealing ring. In other examples, the second sealing member 14 may comprise a sliding coupling between the auxiliary piston 13 and the cavity housing the piston itself, with clearance so as to obtain a suitable sealing effect, in particular at least suitable for allowing some venting or purging of gas. As in this example, the second sealing area may be larger than the first sealing area.

As in the present example, the passage cross-section controlled by the main piston 5 may have a smaller area than the second sealing area. As in the present example, the passage section controlled by the main piston 5 may have a larger area than the first sealing area.

The auxiliary piston 13 may in particular be at least partially arranged in an auxiliary chamber 15, the auxiliary chamber 15 being comprised in axial direction between the first sealing member 7 and the second sealing member 14. The second sealing member 14 may in particular be configured to separate the pilot chamber 9 from the auxiliary chamber 15. As in the present example, the auxiliary chamber 15 may be in fluid communication with the first opening 3 or with the external environment. The control device 1 may in particular comprise a passage 16, the passage 16 being configured to fluidly connect the auxiliary chamber 15 with the first opening 3 or with the external environment. A passage 16 for connecting the auxiliary chamber 15 and the first opening 3 is particularly available inside the main piston 5.

The first end of the auxiliary piston 13 may in particular be configured to interact in contact with the second end of the main piston 5.

As in the present example, the first end of the auxiliary piston 13 may have a straight cross section (straight cross section) smaller than the first sealing area.

The second end of the auxiliary piston 13 may in particular be configured to interact in contact with the first end of the guide piston 8.

The guide stop member 10 may in particular comprise at least one longitudinal element. The guide stop element 10 may in particular comprise at least one stop 17. The guide stop member 10 may in particular comprise at least one spring. The longitudinal element may in particular be coupled to the valve body 2, for example by means of a threaded coupling. The stop 17 can in particular be arranged inside the longitudinal element. The spring may in particular be arranged inside the longitudinal element.

As in the present example, the aforementioned spring may be configured to push the stop 17 to a closed position in which the stop 17 closes the hole formed in the longitudinal element. The hole may in particular communicate with the guide chamber 9. As in this particular example, the pilot piston 8 may be partially received in the bore.

The control device 1 may in particular comprise a brake release valve 18 with a directional valve 19, the brake release valve 18 in particular being configurable to allow disengagement of a hydraulic parking brake 20 operatively associated with a hydraulic motor M (see fig. 4). The valve device 1 may in particular comprise a service opening 21 or a service door, as in the present example the service opening 21 or the service door can be used to connect the brake release valve 18 with the hydraulic parking brake 20.

Fig. 4 shows a diagram of a working apparatus including a distributor D and a hydraulic motor M connected to the distributor D. The working apparatus further comprises the above-mentioned control device 1. The control device 1 is shown in dash-dot lines.

The working device may in particular comprise a pump (of known type and not shown) connected to the dispenser D. The hydraulic motor M may in particular comprise a hydraulic motor with two directions of rotation. The working device may in particular comprise a load lifting device, such as a winch, the traction member of which comprises a hydraulic motor.

As mentioned, the control device 1 may be used for controlling the hydraulic motor M (but also for other actuators, such as hydraulic cylinders for excavators). In particular, when it is desired to use a control valve with a high calibration, the control device 1 may be used, for example, to allow the control valve to be opened safely and to release the brakes (such as the hydraulic parking brake 20) that are normally present when using a hydraulic motor.

In operation, an operator can start a guiding operation, in particular on the dispenser D, by means of a handling device (not shown), for example of a known type.

When it is desired to reduce the load, the pilot fluid entering the control device 1 through the pilot opening P is part of the fluid fed under pressure to the hydraulic motor M.

The pilot fluid must reach the pilot chamber 9 with a pilot pressure in order to exert an axial force on the auxiliary piston 13, which in turn will exert an axial force on the main piston 5.

Note that the guide chamber 9 is in fluid communication with the guide opening P through the guide stopper member 10 and the throttle member 11. It is further noted that the auxiliary chamber 15 is in fluid communication with the first opening 3 (or the external environment) such that the pressure in the auxiliary chamber 15 is substantially equal to the pressure at the first opening 3. The pressure in the auxiliary chamber 15 acts on one side of the auxiliary piston 13 and the pressure in the pilot chamber 9 acts on the other side of the auxiliary piston 13. Furthermore, the pilot opening P is in fluid communication with the service opening 21 via the diverter valve 19.

The main piston 5 may be configured to start moving in the axial opening direction by performing a pre-stroke without opening the passage section of the cavity within the valve body 2 in this initial pre-stroke phase.

The pilot pressure is relatively high and therefore this pressure can release the hydraulic parking brake 20 connected to the service opening 21.

A part of the pilot fluid passes the throttling member 11 and from the throttling member 11 to the pilot chamber 9, exerting a thrust action on the secondary piston 13 and closing the pilot-stop member 10 (in particular the stop 17), so that the primary piston 5 will move further in the opening under the action of the pilot fluid passing the throttling member 11.

The main piston 5 moves until it opens the passage section, so that the working flow of fluid can pass and the load can start to drop.

In order to interrupt the lowering of the load, the supply of pressurized fluid is interrupted, so that the pilot opening P no longer receives pressurized fluid. The pilot fluid located in the valve body 2 can be discharged through the check member 12. The main piston 5 is moved in the closing axial direction by the urging of the actuating member 6 (spring), the force of the actuating member 6 is no longer counteracted by the auxiliary piston 13, the main piston 5 closes the passage section and breaks the connection between the first opening 3 and the second opening 4.

The control device 1 forms a control valve which, after an initial opening moment, is able to subsequently continue the opening phase in a comparatively rapid manner. Essentially, the control device 1 is only able to perform an effective control of the hydraulic actuator during the initial opening phase of the stop, while the stop can open quickly during a period of time after this initial opening phase, i.e. a time frame in which strict control is no longer necessary and the flow of fluid can increase quickly, thus reducing energy losses.

In fact, the auxiliary piston 13 can be used as an additional pilot piston which allows to obtain a relatively high piloting ratio, in particular greater than 6: 1. or greater than 8: 1. or a guide ratio greater than 10: 1. The piloting ratio may in particular be the ratio between the area of the section of the piloting piston 13 (or of the second sealing area, or of the section defined by the second sealing member 14) and the annular area defined by the difference between the passage section controlled by the main piston 5 and the first sealing area (or of the section defined by the first sealing member 7). In the particular example shown, the piloting ratio is approximately equal to 13: 1.

the control device 1 may be used in particular for controlling the movement of a load. The piloting ratio is one of the parameters regulating the opening of the control device 1. In particular, the pilot pressure required to open the control device 1 and thus move the load is a function of the pilot ratio (which will depend on the configuration of the control device 1), of the calibration pressure (which will depend on the calibration of the control device 1) and of the pressure caused by the load (which will depend on the specific case of use).

The throttling member 11, which in this case comprises a throttling screw, allows to limit the instability of the system. The one-way member 12 (comprising in this case a check valve) performing some kind of bypass with respect to the throttling member 11 allows to eliminate or at least significantly reduce the closing (or opening) delay due to the need to empty (or fill) the volume of the pilot chamber 9.

The auxiliary piston 13 essentially forms an additional pilot piston which ensures a high calibration of the device. At the same time, the device itself can be completely opened very quickly.

The auxiliary piston 13 also allows a stabilizing action of the device. In fact, the forces acting on the main piston 5 in the control device 1 are particularly large, since the auxiliary piston 13 can act on one side of the main piston 5 with a large diameter, and the actuating member 6 can act on the other side with a relatively very rigid elastic member. This will give rise to the fact that the hydraulic flow forces will influence the opening of the main piston 5 to a lesser extent.

Claims

1. A control device (1) comprising:

-a valve body (2) having at least one inner cavity for the passage of a fluid, a first opening (3) for the passage of a fluid, a second opening (4) for the passage of a fluid, a guide opening (P);

-a main piston (5) axially movable in the cavity in such a way as to be able to assume at least one closed position, in which the main piston (5) closes a passage section between the first opening (3) and the second opening (4), and at least one open position, in which the main piston (5) opens the passage section;

-an actuating member (6) arranged at a first end of the main piston (5) for applying an axial force to the main piston (5);

-a first sealing member (7) located at the main piston (5) for defining a first sealing area between the second opening (4) and a second end of the main piston (5) opposite to the first end;

-a pilot piston (8) movable coaxially with the main piston (5) within a pilot chamber (9) inside the valve body (2);

-a guide stop member (10) configured to interact with the guide piston (8) to control the passage of fluid between the guide opening (P) and the guide chamber (9);

-a throttling member (11) configured to throttle between the guide opening (P) and the guide chamber (9);

-a unidirectional member (12) arranged in parallel with respect to the throttling member (11);

characterized in that the control device (1) further comprises an auxiliary piston (13) coaxially movable with respect to the main piston (5), a first end of the auxiliary piston (13) facing the second end of the main piston (5), a second end of the auxiliary piston (13) facing a first end of the pilot piston (8), the pilot chamber (9) being delimited at least partially by the second end of the auxiliary piston (13).

2. A control device (1) according to claim 1, characterized in that the device comprises a second sealing member (14), the second sealing member (14) being located at the auxiliary piston (13) for defining a second sealing area larger than the first sealing area; the auxiliary piston (13) is at least partially arranged in an auxiliary chamber (15), the auxiliary chamber (15) being comprised axially between the first sealing member (7) and the second sealing member (14).

3. Control device (1) according to claim 2, characterized in that said auxiliary chamber (15) is in fluid communication with said first opening (3) or with the external environment.

4. Control device (1) according to any one of claims 1-3, characterized in that the first end of the auxiliary piston (13) is configured to interact in contact with the second end of the main piston (5).

5. Control device (1) according to any one of claims 1-3, characterized in that the second end of the auxiliary piston (13) is configured to interact in contact with the first end of the guide piston (8).

6. A control device (1) according to any one of claims 1-3, characterised in that the first end of the auxiliary piston (13) has a straight section in contact with the second end of the main piston (5) and that the area of the straight section is smaller than the first sealing area.

7. Control device (1) according to any one of claims 1 to 3, characterized in that said guide and stop member (10) can selectively assume at least one open configuration, in which said guide and stop member (10) opens a fluid passage, and a closed configuration, in which said guide and stop member (10) closes said fluid passage and said fluid flows from said guide opening (P) to said guide chamber (9) through said throttling member (11) to move said auxiliary piston (13).

8. Control device (1) according to any one of claims 1 to 3, characterized in that said actuating means (6) comprise elastic means configured for pushing said main piston (5) towards said closed position.

9. Control device (1) according to claim 2 or 3, characterized in that the area of the passage cross-section is smaller than the second sealing area and/or larger than the first sealing area.

10. Control device (1) according to any one of claims 1 to 3, characterized in that the guide and stop means (10) comprise at least one longitudinal element coupled to the valve body (2), a stop (17) and a spring arranged in the longitudinal element, the spring being configured to push the stop (17) to a closed position in which the stop (17) closes a hole formed in the longitudinal element communicating with the guide chamber (9), the guide piston (8) being partially housed inside said hole.

11. A control device (1) according to any one of claims 1 to 3, characterised in that the throttling member (11) comprises a closing element coupled with the valve body (2) by means of a threaded connection defining a passage for the fluid, said closing element being provided with an adjustment means configured to adjust the screwing of the closing element and thus the throttling member (11), said non-return means (12) comprising a non-return valve configured in the closing element.

12. A control device (1) according to claim 3, characterized in that the auxiliary chamber (15) is in fluid communication with the first opening (3) or with the external environment by means of a channel (16) formed in the main piston (5).

13. Control device (1) according to claim 10, characterized in that the longitudinal element is coupled to the valve body (2) by means of a threaded coupling.

14. A working apparatus, characterized in that the working apparatus comprises: pump, distributor (D) connected to the pump, hydraulic motor (M) connected to the distributor (D) and control device (1) connected to the hydraulic motor (M) and to the distributor (D) and made according to any one of the preceding claims.