EP0615583B1 - Energy recovering device - Google Patents

Abstract

PCT No. PCT/EP92/02797 Sec. 371 Date Aug. 26, 1994 Sec. 102(e) Date Aug. 26, 1994 PCT Filed Dec. 3, 1992 PCT Pub. No. WO93/11363 PCT Pub. Date Jun. 10, 1993.A device for recovering energy, in particular potential energy in working machines, has a hydraulically actuatable working cylinder linked to a hydropneumatic storage. At least another working cylinder is provided. The two working cylinders are mutually linked by their rod end chambers to transfer fluid and are linked to a hydraulic circuit having at least one pump. The other working cylinder is also linked at its piston end chamber to a hydraulic circuit having a pump. The energy generated by the movements of the working machine can be effectively stored in a failure-proof manner and called back at defined moments in time.

Description

The invention relates to a device for recovering energy, in particular of location energy in working machines, with the characteristics of Preamble of claim 1.

Such a device is previously known from British Patent 1,231,585. In this known device used in a backhoe becomes part of the hydraulic energy when the arm is lowered stored in the working cylinder in the memory and an additional one Fluid quantity after the arm has passed a predeterminable position returned to the tank by means of a button arrangement. To lift the Poor can then the energy stored in the memory in the form of stored fluids to support the working cylinder on this again be delivered. This known device is not able to do anything worth mentioning Scope of usable energy recovery from the storage to enable.

In other known devices for recuperating the position energy this energy with the help of a system of proportional hydraulic distributors stored in the form of hydrostatic energy. The related ones Devices are complicated and therefore not profitable.

In another known device for energy recovery Location energy (PL-PS 127 710) is the working organ with an additional, single-acting hydraulic linear motor (working cylinder) provided stored between the machine frame and the work organ and with a hydropneumatic accumulator and a distributor with a container or a hydrogenerator is connected. Are also disadvantageous in this device, the relatively high cost, in particular in terms of the additional linear motor and the distributor what again lowers the profitability of the device.

In another known device for recuperating the position energy (Czech copyright certificate 268 933) is the working organ with an accumulator linear motor provided, the piston chamber is filled with compressed gas and with the reservoir of the same is connected. This device can be not completely seal against accidental gas leakage, so that the device can lose its function after a relatively short time. The static load capacity is also not constant because of the gas pressure the position of the work organ of the excavator is changeable. Furthermore, the fully active lifting power of the machine only together with the additional enable hydraulic working cylinder.

JP-A-60-250128 is a device for recovery of energy known in which between the piston chamber of the with the Memory connected working cylinder and the memory a switching device is available. In this known device can be completely the piston-side amount of fluid in the working cylinder, which is connected to the accumulator connected, give in to this, the related process several times is repeatable in succession, so that a precisely quantifiable amount of energy can be stored in the memory for later retrieval. It However, it has been shown in practical tests that a related Design is not enough to achieve a satisfactory energy recovery to get.

Another disadvantage of all known devices for recuperation Location or the kinetic energy of the respective work organ also exists in that the active force decreases when the working organ is lowered.

Starting from this prior art, the object of the invention based, while maintaining the advantages of the known energy recovery devices an improved device for energy recuperation to accomplish.

A relevant task is with the features of claim 1 in solved in its entirety. The fact that according to the characteristic part of the Claim 1 of the piston chamber of the hydraulic working cylinder with the hydropneumatic accumulator via a seat valve, especially in the form of a Cartridge valve, which interacts with a control distributor, which is connected to a pressure relay as part of a control device is, and that the control device with its control input to one Low pressure branch is connected to the movable parts of the Working machine, especially in the form of a boom, has it It has been shown that higher amounts of energy can be recovered than with the previously known devices. The control behavior is also the Device improved and the scope of the necessary circuit optimized.

In a preferred embodiment of the device according to the invention between the piston chamber of the working cylinder connected to the accumulator and the accumulator itself has a hydraulically actuated switching device, for example in the form of a 2/2-way valve.

In a further preferred embodiment there is between the piston space of the working cylinder connected to the memory and this one hydraulically actuated switching device, for example in the form of a 3/2-way valve, switched, which has a tank connection. Are preferred here the hydraulically actuated switching device and the switching device connected in series.

In a particularly preferred embodiment of the invention The device is the piston chamber of the working cylinder connected to the accumulator by means of a fluid-carrying line with the piston chamber of the other Working cylinder connected, in which a check valve or a so-called. One-way valve is switched. The one-way valve is preferably a throttle element hydraulically connected in series and assigned a back branch or a branch line of communicating piston rod spaces of the mentioned hydraulic linear units is available via the distributor of the hydraulic machine system with the piston chamber of the hydraulic, at hydropneumatic accumulator connected by means of the one-way valve Linear motor in connection, this back branch or the branch line also connected to a liquid container by means of a pressure valve is.

The piston chamber of the hydraulic working cylinder is with the hydropneumatic Accumulator by means of a saddle valve, a control distributor or a control device formed by a pressure relay, this device with its control input on a low pressure branch connected from the work organ. Between a tank connection of the control distributor of the control device and the piston chamber of the hydraulic drive cylinder connected to this device is a Changeover or changeover valve provided, the output side to a feed channel connected. The control unit's tank connection communicates with the interconnected piston rod spaces of the drive cylinders, which further interconnects with a hydraulically operated cylinder are, the axis of symmetry preferably with the axis of symmetry of the cone of a safety valve is identical, the piston of this cylinder on the Side of the supply of hydraulic fluid to the safety valve against the forehead of the Cone of this valve is supported.

The main advantage of the device for recuperation of the invention Positional energy of a work organ of construction or agricultural machinery consists in that by interconnecting them with one of the hydraulic linear motors (Working cylinder) for lifting or lowering the boom enables one relatively high working pressure or relatively low flow rates of hydraulic fluid use what reduces the manufacturing costs and at the same time the Efficiency of the device increases, thereby increasing the overall profitability of the Device is increased. It is also advantageous that the device has an overall represents compact, relatively small unit, which may also be as one Additional device for retrofitting to already delivered Working machines can be used. Ultimately, the invention enables Device for lifting and lowering the work organ, for example in the form of a boom of the machine in question, the full active force that theoretically results to also be achieved.

The device according to the invention is in the following with reference to the drawing explained in more detail.

1 to 4 show different embodiments based on circuit diagrams the device for energy recovery.

1 shows an embodiment of the device according to the invention with two rectilinear hydraulic motors or working cylinders 3.5 for lifting and lowering a working device 2, for example in the form of a hydraulic one Backhoe. The piston chamber 32 of the drive cylinder 3 is with a Hydraulic fluid filled and to a hydropneumatic memory 4, for example in the form of a membrane or bladder accumulator, which can be connected with a safety valve 7 and one connected to a liquid container 9 Intake valve or check valve 11 is provided. The piston rod space 31 of the working cylinder 3 is on the piston rod chamber 51 of the further working cylinder 5 connected.

In the described embodiments, there can be between the piston space 32 of the drive cylinder 3 and the hydropneumatic memory 4 a hydraulically actuated switching device (not shown) must be switched on, a switching device (not shown) to this switching device can be switched on in series in the circle. The piston chamber 32 of the double-acting, linear working cylinder 3 is in front of Switching device to a liquid container 9 via a safety valve 7 in Form of a pressure relief valve connected. The hydraulic switching device is e.g. a valve in the form of a 2/2-way valve that next to a hydraulic signal can also be actuated by an electrical signal, which by swiveling the control device in by the operator the lifting or lowering position of the work device 2 is caused.

The hydraulic switching device is, for example, a distributor in the form a 3/2-way valve, which is also operated by a hydraulic or electrical Signal can be actuated, which by a pressure increase in the through Piston rod chambers 31 and 51 of the working cylinders 3 and 5, respectively Work facility 2 is caused.

When stationary, the static load capacity of the working device 2 is in the form of a Arm or boom in the sense of lowering by the on the safety valve of the hydraulic system of the machine set static pressure determines which in the piston chamber 52 of the working cylinder 5 of the working device 2 acts, and further determined by the current working pressure in the hydropneumatic accumulator 4, which in the piston chamber 32 of the accumulator hydraulic motor or working cylinder 3 acts.

It is advantageous if the pressure of the safety valve 7 with the pressure of the Corresponding safety valve of the hydraulic system of the working machine, is preferably set the same. The static load capacity of the work equipment 2 in the sense of lowering is then only through that on the safety valve of the hydraulic system of the machine set static Pressure determines which in the piston rod spaces 31 and 51 of the working cylinder 3 or 5 acts. This makes both sides more static Load capacity reached. When the working device 2 is lowered, the hydraulic fluid from the hydraulic system of the machine to the piston rod area 51 of the working cylinder 5 and the piston rod chamber 31 of the storage hydraulic motor or working cylinder 3 supplied. The hydraulic fluid is from the Piston chamber 52 via the hydraulic system of the machine into the liquid container 9 and the filling liquid from the piston chamber 32 of the working cylinder 3 pressed out into the hydropneumatic accumulator 4. By printing the Liquid in the hydropneumatic accumulator 4 becomes the piston of the working cylinder 3 raised, whereby the lowering of the working device 2 braked without the stored in the hydropneumatic memory 4 Energy is consumed.

The device according to the invention for recuperating the position energy of a Work equipment can be used to advantage in construction and earth-moving machinery find, but also be advantageous for machines with a high Action force of the work facility is required, e.g. for loading machines, Hoists, universal hydraulic excavators as well as for loading and unloading devices.

The piston spaces 52 and 32 of the above-mentioned working cylinders 5 and 3, respectively communicate with each other via a one-way or one-way valve 14. At the Embodiments is the one-way valve 14 with a throttle element 15, for example in the form of an adjustable throttle valve, a throttle disc or throttle nozzle, hydraulically connected in series; where appropriate, the Piston chambers 52 and 32 together using a freely definable throttle profile connected. One of the interconnected piston rod spaces 51 and 31 of the cylinder 5 and 3 leading rear display or branch line In the embodiments according to FIGS. 1 and 2, 12 is behind the distributors of the hydraulic machine system with the piston chamber 32 of the hydraulic working cylinder 3 via a one-way or one-way valve 11 connected. In addition, the branch line 12 is with a liquid container 9 via a pressure valve 10 in connection, which is preferably on a Medium pressure in the branch line 12 of the standard hydraulic system Machine is set.

In the embodiment according to FIG. 1, the piston chamber 32 is the working cylinder 3 with the hydropneumatic accumulator or storage 4 by means of of the control device 65. The control device 65 has a saddle or cartridge valve 61, a control manifold 62 in the form of a 4/2-way valves and possibly a pressure relay 63, which in the case an electrically controllable distributor 62 also by an electrical one Limit switch can be formed.

With its control input 64, the control device 65 has a low-pressure branch 13, which cooperates with the boom 2, hydraulically connected or - if the mentioned electrical limit switch is used is a spring loaded stop within the reach of or close to the movable one, with the slide of the section of the distributor of hydraulic Machine system for moving or starting the boom 2 mechanically coupled components attached.

In the embodiment according to FIG. 2 there is between a channel T of the control distributor 62 and the piston chamber 32 of the hydraulic, on the device 65 connected drive cylinder 3, a shuttle valve 16 installed, the output of which is connected to a feed channel P of the control distributor 62 stands. This channel T of the control distributor 62 leading to the tank continues to connect to the piston rod rooms communicating with each other 31 and 51, which have a hydraulically actuated actuating cylinder 17th are connected. The longitudinal axis of symmetry of this cylinder 17 is such elongated axis of the cone of the safety valve 7 identical. The piston 18 of the hydraulically actuated actuating cylinder 17 preferably has the Diameter which corresponds to the diameter of the active part of the cone of Safety valve 7 corresponds, and is on the side of the supply of hydraulic fluid supported to the safety valve 7 against the conical end of this valve 7.

The performance of the engine and hydrogenerators can preferably be either by using a less powerful drive unit or by changing the setting, e.g. Decrease in engine speed by changing the control lever stop of the injection pump of the diesel engine, be reduced.

In the variant shown in FIGS. 1 and 2, the control device is located 65 in the neutral position of the actuator of the boom 2 in the connected position. The static load capacity, again in the sense of lowering the boom 2 is seen through the on the secondary safety valve of the hydraulic Machine system and the pressure set on the safety valve 7 set pressure determined. The pressure of the safety valve 7 is preferably equal to the pressure of the hydraulic machine system set.

In the neutral position of the boom 2 in the embodiment according to FIG. 2 the full static load-bearing capacity in the sense of lifting the boom 2 achieved because the cone end of the safety valve 7 forming piston 18 Safety pressure of this valve 7 to zero at full pressure in the communicating piston rod spaces 31 and 51 decreases if this Pressure the saddle valve or cartridge valve 61 of the control device 65 at the same time completes what a pressure drop and a loss of hydrostatic Avoiding energy in the hydropneumatic accumulator 4 helps. When swinging out the actuator or the starter of the boom 2, the pressure fluid from the piston chamber 52 by means of the distributor of the hydraulic machine system in the liquid container 9 and from the Piston chamber 32 in the hydropneumatic accumulator 4 either directly or via the opened cartridge valve 61 of the control device 65 pushed out. Due to the pressure in the hydropneumatic accumulator 4, the also acts in the piston chamber 32, the piston of the hydraulic linear motor 3 raised, thereby lowering the boom 2 without wasting the Energy is braked because it is in the hydropneumatic accumulator 4 saves again.

When the boom 2 is lowered, e.g. against the resistance of the earth's surface when digging, the active lowering force decreases by a lifting force that corresponds to that in Hydropneumatic accumulator 4 generated and acting in the piston chamber 32 Pressure is proportional.

According to Fig.2 is when lowering the boom 2 and due to the resistance the amount of earth reaches the full active lowering force because of the cone end of the safety valve 7 driving piston 18 the same safety pressure up to zero at full pressure in communicating piston rod spaces 31 and 51 decreases when this pressure simultaneously closes the closing process of the cartridge valve 61 of the control device 65 causes what the Pressure drop and loss of hydrostatic energy from the hydropneumatic Accumulator 4 avoids.

When the actuator of the boom 2 is swung out, the hydraulic fluid is expelled the hydraulic machine system supplied to the piston chamber 52, which is the Raising the boom 2 caused by this in the hydropneumatic Accumulator 4 generated and the piston of the hydraulic working cylinder 3 either directly or using the open saddle or cartridge valve 61 the pressure causing the control device 65 is raised, whereby the energy stored in the hydropneumatic accumulator 4 is exploited. As long as the pressure in the hydropneumatic accumulator 4 under the pressure value in the piston chamber 52 decreases, the piston chamber 32 of the hydraulic Linear motor 3 by means of the one-way valve 14, possibly also by means of of the throttle element 15, fed with the hydraulic fluid, whereby the through Leakage of the devices caused losses of hydraulic fluid at least be compensated for during a possible, by opening the Throttle element 15 created excess pressure fluid to achieve full working pressure in the hydropneumatic accumulator 4 even with one Reduction of the stroke of the boom 2 ensures. With an even bigger one Opening of the throttle element 5 or the same comes out of operation it when lifting the boom 2 in a certain position to compensate for the Pressure values in the piston chambers 51 and 32, so that the hydraulic fluid in both rooms 52,32 only from the hydraulic machine system is delivered what the achievement of the full active lifting force of the boom 2 ensures. The hydropneumatic accumulator closes at the same time 4 and its pressure does not exceed the value of the balancing pressure, this compensation pressure even in the highest position of the boom 2 in the piston chambers 32 and 52 can be reached by means of the working cylinders.

The embodiment having the throttle element 15 is suitable for loading machines with relatively high requirements in terms of active lifting power of the boom and for so-called sinking systems of hydraulic excavators with low and irregular lifting frequency of the boom. Also suitable the embodiment according to FIG. 2 particularly when used on machines with high requirements with regard to the active lowering force of the work organ.

Another particularly advantageous embodiment of the invention The device is shown in FIGS. 3 and 4, but only partially Play relevant circuit. The cartridge valve shown there or seat valve without seal has an area ratio of 1:12. Around To obtain an optimal solution is the rod-side volume of the piston spaces 31 and 51 designed larger than the volume of the working cylinder on the Piston side 32 or 52. Care is preferably taken here that the free ring area of two working cylinders is larger than the loadable Piston area of a cylinder.

The pressure relay shown in Figure 3 or the pressure switch 63 is from to a pilot control device via line 40 and has one Branch 41 to the second control block of the machine. The second control block has a return line 42 coming from the piston rod space, which is connected to the hydraulic system 43 of the machine, which has at least has a feed pump for the fluid and a tank drain. The second Control block 44 is connected to the hydraulics 43 and to the communicating connection switched between the piston rod spaces 31 and 51. A return 45 of the first control block is shown at the top right in FIG. At least one further control block 45 connected to a feed pump and one Tank is connected is also to the piston chamber 52 of the working cylinder 5th connected. The embodiment shown in Figure 3 is special suitable for pressure differences of 100 to 300 bar, the another embodiment according to Figure 4 is particularly suitable for pressure differences from 180 to 300 bar.

Claims (7)

1. Device for recovering energy, especially positional energy in processing machines, with a hydraulically operated working cylinder (3), which can be connected to a hydropneumatic accumulator (4), in which case at least one further working cylinder (5) is present and the respective working cylinders (3, 5) are connected to each other at the rod end in a manner carrying fluid and are connected to a hydraulic circuit, which comprises at least one pump, and in which case the respective further working cylinder (5) is connected at the piston side likewise to a hydraulic circuit with a pump, characterised in that the piston chamber (32) of the hydraulic working cylinder (3) is connected to the hydropneumatic accumulator (4) by way of a seated valve (61), in particular in the form of a cartridge valve, which cooperates with a control distributor (62), which as part of a control device (65) is connected to a pressure relay (63), and that the control device (65) is connected by its control input (64) to a low pressure branch (13), which cooperates with the movable parts of the processing machine, in particular in the form of an arm (2).
2. Device according to Claim 1, characterised in that a switching device is located between the piston chamber (32) of the working cylinder (3) connected to the accumulator (4) and the accumulator (4).
3. Device according to Claim 1 or 2, characterised in that connected between the piston chamber (32) of the working cylinder (3), which is connected to the accumulator (4), and the latter is a change-over device, which comprises a tank connection.
4. Device according to Claims 2 and 3, characterised in that the switching device and the change-over device are connected hydraulically in series one after the other.
5. Device according to one of Claims 1 to 4, characterised in that the piston chamber (32) of the working cylinder (3) connected to the accumulator (4) is connected by means of a fluid-carrying line to the piston chambers (52) of the other working cylinders (5), in which a non-return valve (14) is connected.
6. Device according to Claim 5, characterised in that the non-return valve (14) is connected in series with a restrictor member (15), that a branch line (12) is connected using a further non-return valve (11) in the line between the accumulator (4) and the piston chamber (32) connected thereto, which is part of the hydraulic circuit, and that the branch line (12) is further connected to a liquid container (9) by way of a non-return valve (10).
7. Device according to Claim 6, characterised in that provided between a tank connection (T) of the control distributor (62) and the piston chamber (32) of the cylinder (3) connected to the accumulator (4) is a two-way valve (16), whereof the output is connected to a supply line (P) of the control distributor (62), whereas the tank connection (T) of the control distributor (62) is connected to the communicating piston rod chambers (31 and 51) of the working cylinders (3 or 5), which are in turn connected to a hydraulic operating cylinder (17).

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