DE2252234A1 - HYDRAULIC CIRCUIT - Google Patents

Description

Subject: itydraulic circuit The invention relates to a hydraulic circuit with two in particular provided with pressure accumulators Sub-circuits and pressure generators assigned to these sub-circuits, as well as check valves and pressure-actuated switching valves, which when a preselectable maximum pressure is reached prevent a further increase in pressure in a partial circuit there.

Hydraulic circuits of this type are already known. For example, in the book "Basic plan of hydraulic systems" by Dr. Heinz Zoebel, Krauskopf-Verlag 1 19 * 1 on page 20 described a cycle, which contains two pumps serving as pressure generators. One of these pumps delivers in a high pressure circuit, while the other pumps in a low pressure circuit, which is separated from the pressure circuit by a check valve. Both circles are Accumulator and shut-off valves assigned. First, both pumps deliver to the Generating a rapid traverse. As soon as after a certain pressure build-up, for example A certain pressure is reached in the low-pressure circuit when a piece of equipment is tensioned the shut-off valve switches to unpressurized circulation. The pump of the hypertension circuit continues to convey on its own until there is sufficient pressure in the high-pressure circuit for tensioning is reached.

So then this pump is also depressurized via a shut-off valve Circulation switched. The pressure maintenance takes place via the pressure accumulator. From this description it can be seen that both sub-circuits close again unite a single circuit that leads to a consumer. This Circuit can therefore not be used to separate two different consumers to take care of each other. Such an application is, for example, in hydraulic Systems of motor vehicles given where it applies, for example a servo brake and to supply a power steering with pressure medium. To the size of the necessary pressure generator To keep them small, accumulators are usually built in, which does the job have to store pressure medium in times of low consumption.

When a maximum pressure is reached in a partial circuit, one could analogous to the circuit described above with the help of a shut-off valve Switch pressure medium to pressureless circulation. Since the used pressure accumulator in addition to their function as a storage element and the associated Possibility of reducing the pressure generator also the task of a security element if the pressure generator fails, it is desirable to have the pressure accumulator always filled or always refilled as quickly as possible.

The object of the invention is based on this consideration in it, not only the associated pressure generator to fill up a pressure accumulator to use, but at least temporarily both pressure generators for the replenishment to use.

This replenishment should also be possible when both partial cycles different maximum pressures are assigned.

This object is achieved according to the invention in that each Pressure generator is assigned a valve arrangement which is below an opening pressure in a switching position brought about by spring force or the like a connection caused between the pressure generator and the partial circuit assigned to the pressure generator and when the maximum pressure is reached by applying the pressure of the partial circuit switches against the spring force in a switching position in which the said connection is blocked and a further connection from the pressure generator to a flow line via is opened to the other partial circuit, each overflow line via a first and a second on-off valve with a system connected in series with the first lower pressure can be connected and one of the on-off valves at tiöchstdruck of the first partial circuit and the other at the maximum pressure of the second partial circuit be switched into the "On" switch position, with an outflow of pressure medium from the sub-circuits into the system with lower pressure through check valves is prevented. The valve arrangement can consist of two on-off valves, from which one occupies the "closed" switch position when the other is in the switch position "Up" is. But it is also possible to combine the two open-close valves into a single one summarize in the manner of a pressure-switched 3/2-way valve, which in his Switch position connects the pressure generator with the partial circuit and blocks the overflow line and in a second switching position when the maximum pressure is reached, the partial circuit and connects the pressure generator with the overflow line. In a similar way Way, it is possible to each have the first and second open-close valves in the connection between the overflow lines with dell system of lower pressure to 4/2-way valves summarize which in a first switching position all connections from each other separate and in a second switching position each belonging to a connection Connect connections. Finally, it is also possible to have all of the pressure of a partial circuit to combine controlled valves into a single valve, which the function of a valve.

On the basis of the exemplary embodiments shown in the figures the invention is explained in more detail.

FIG. 1 shows a hydraulic circuit diagram according to the invention in the form of a hydraulic circuit diagram hydraulic circuit, in which only A; lt valves are used as switching valves were used.

Figure 2 shows a circuit diagram with the same function, in each case two Ruf-. 'u valves were combined into a single valve.

FIG. 3 shows the summary of FIG 4 on-off valves for a 7/2 valve.

Two sub-circuits 1 and 2 are assigned to pressure generators 3 and 4, which Suck in pressure medium from a reservoir 5. The pressure generator 3 promotes this Pressure medium into a pressure line 6 which leads to a connection 1> of an open-close valve 7.

This on-off valve 7 has a further connection A, of which a line 8 to a pressure accumulator 9 or to a not shown in detail Consumer lo leads. From the consumer lo a line 11 leads back to the storage container 5. The on-off valve 7 is activated by a spring 12 below a maximum pressure in a switching position a held, in which the connections and and A with each other are connected. This can be done via a control line 13 branching off from line 8 Open-close valve 7 is switched to a switching position b when the maximum pressure is reached in which the connections P and A are separated from each other. The pressure generator 4 conveys pressure medium in a line 14 which leads to a connection P1 of an open-close valve 15 leads. The on-off valve 1D has a further connection A1, one of which Line 16 to a pressure accumulator 17 or a consumer not shown in detail 18 leads, from which a line l9 leads back to the reservoir 5. The on-off valve 15 is by a spring 20 below a maximum pressure in a switching position c held, in which the two connections P1 and A1 are connected to one another. When the maximum pressure is reached, the on-off valve 15 is via one of the line 16 branching control line 21 switched into a switching position a, in which the connections P1 and A1 are separated from each other. One branches off the line 6 from line branches 22, 23 and 24 existing connection, which in the management 16 opens. An open-close valve 25 is connected between the line branches 22 and 23, which has a connection P2 to the branch line 22 and a connection A2 the branch line 23 is connected. The branches 23, 24 are via a check valve 26 opening in the direction of branch line 24 is separated.

The open-close valve 25 is actuated by a spring 27 below the maximum pressure held in a switching position e, in which the connections P2 and A2 from each other are separated. When the maximum pressure is reached, the on-off valve 25 is via the Control line 13 is switched to a switching position f, in which the connections P2 and A2 are connected to each other. From the line 14 branches from a line branch 28, 29 and 30 confirming connection to line 8. The branch line 28 is connected to a connection 1> 3 of an open-close valve 31, which is another Terminal A3, to which the branch line 29 is connected. The branches of the line 29, 30 are activated by a check valve that opens in the direction of branch line 30 32 separated from each other. A spring 33 causes that below a maximum pressure Remaining of the open-close valve 31 in a switching position g, in which the connections P3 and A3 are separated from each other. When the hole pressure is reached, over the control line 21, the open-close valve 31 is switched to a switching position h, in which the connections P3 and A3 are connected to one another. From the branch of the line 23 branches off a line 33 to a port B of an open-close valve 34 from, which has a further connection C and a line connected to it 35 is connected to a connection B1 of an open-close valve 36. Fin further AD conclusion C1 of the open-close valve 36 is connected to the storage container 5 via a line 37. The open-close valve is below the maximum pressure attainable in sub-circuit 1 held by a spring 38 in a switching position i, in which the connections and are separated from each other. When the maximum pressure is reached, a with the tax office.

device 13 communicating control line 39 the open-close valve 34 in a Switch position j switched, in which the connections 13 and C are connected to one another are. A spring 40 causes the maximum pressure that can be reached in sub-circuit 2 to be below the maximum pressure the open-close valve 36 remains in a switching position k, in which the connections B1 and C are separated from each other. When the 2-hole pressure is reached, a with the control line 21 communicating control line 41 the open-close valve 36 in a switching position 1 is switched, in which the connections Bl and C1 with each other are connected.

To the line 29, a line 42 is connected, which to a Connection B2 of an Auf-su-valve part 43 leads, which has a further connection C2. A line 44 leads from the connection C2 to a connection B3 of an open-close valve 45, which has a further connection C3, from which a line 46 returns leads to the reservoir 5. The on-off valve 43 is supported by a spring 47 below of the chst attainable in sub-cycle 1 pressure in the switch position m held. When the maximum pressure is reached, a control line 39 starts Switch a switching position n, in which the connections B2 and C2 with each other are connected. The on-off valve 45 has a spring 48 which is below the The opening pressure achievable in the sub-circuit 2, the open-close valve 45 in a switching position o hold, in which the connections B3 and C3 are separated from each other. Uei Lrreichen When the maximum pressure is reached, the control line 41 is used to switch to a switching position p, in which the terminals B3 and C3 are connected to one another.

To explain the function it is assumed that according to the drawn Switching positions the pressure generators 3 and 4 in the sub-circuits assigned to them 1 and 2 promote. It is also assumed that the part 1 belongs to the sub-cycle Pressure accumulator 9 be the first to reach its maximum pressure. In this case, the Open-close valves 7, 25, 34 and 43 simultaneously from switching positions a, e, i and m switched to switch positions b, f, j and n. The pressure medium now flows from the pressure generator 3 via the lines 6 and 22, the connections Pi and A2, the line branch 23, the check valve 26 and the line branch 24 in the partial circuit 2 belonging line 16.

An outflow into the reservoir 5 is despite the connection of the Ports B and C of the open-close valve 34 prevents the open-close valve 36 still remains in its switching position k, in which the connections B1 and C1 from each other are separated. It should be noted here that an overflow from the pressure generator 3 in sub-circuit 2 also takes place when the pressure in sub-circuit 2 is higher than that in sub-cycle 1. Fin impermissibly high charging of the sub-cycle 1 is prevented that the on-off valve ti in its switching position b the Connection between ports P and A blocked.

A flow from the sub-circuit 2 via the branch 28, the Open-close valve 31, the line branch 2p, the check valve 32 and the line branch 30 is prevented by the fact that the open-close valve 31 is also still in the connections P3 and blocking switch position g persists. When finally in sub-cycle 2 Once the maximum pressure has been reached, the open-close valves 15,31,36 are activated at the same time and 45 from their switch positions c, g, k and o to switch positions d, h, l and p switched. This means that the pressure medium from the line branch 23 is depressurized can flow back into the storage container. The pressure generator can do this in the same way 4 promoted pressure medium via the line branch 28, the connections P3 and A3, the Line branch 29, the line 42, the connections B>, C2l the line 44, the Connections B3 and C3 as well as the line 46 in the supply container 5 circulate without pressure. The pressure accumulators 9 and 17 can be emptied on the one hand through the open-close valves 7 and 15 prevented, which are each in their locked position. On the other side is an outflow through the check valves 26, 32 prevented. Only when the pressure in sub-circuits 1 and 2 has reached the respective If the maximum pressure has fallen below a certain level, the corresponding on-off valves through the springs in the switching position shown.

So that switching does not occur with very small pressure differences takes place, whereby the pressure generators would only deliver without pressure for a very short time, the on-off valves can be provided with detents. This causes a Switching only takes place after an adjustable pressure interval. A description in the event that the partial circuit 2 is the first to reach its maximum pressure, provides because the processes are analogous to those described.

The arrangement according to FIG. 2 differs from that according to FIG 1 primarily in that two open-close valves form a single valve were summarized. To better record the remaining similarities too can, therefore, have the same reference numerals for functionally identical connections as used in Figure 1. Also, all other functionally identical parts were made also provided with the same reference numerals. The pressure generator 3 promotes pressure medium via line 6 to a connection P of a pressure-switched 3/2-way valve 49, which has two further connections A and A2, the connection A is on the line 8 and one in this line 8 built check valve 50 with the Pressure accumulator 9 or connected to the consumer lo. An overflow line is connected to connection A2 51 connected, which opens into line 16. The pressure generator 4 promotes Pressure medium via line 14 to a connection 1 of a pressure-switched 3/2-way valve 52, which has two further connections A1 and A3. At connection A1 is the Line 16 connected, which via a check valve 53 with the pressure accumulator 17 or consumer 18 is connected. The check valve 53 opens in the direction Pressure accumulator 17. The confluence of the overflow line 51 takes place upstream of the check valve 53. An overflow line 54 is connected to the connection A3, which is upstream from the check valve 50 opens into the line 8.

When the maximum pressure is reached in sub-circuit 1, the Control line 13 a switching of the 3 / L-way valve 49 from one of the ports P and A connecting switching position q into a connecting the connections E 'and A2 Switch position r.

Switching takes place when the maximum pressure is reached in the valve circuit 2 of the 3/2-way valve 52 from a switching position connecting the ports P1 and A1 s into a switching position t connecting the connections P1 and A3 via the control line 21. Lines 55 and 56 are connected to overflow lines 5l and 54, which lead to ports B and B2 of a pressure-switched 4-way valve 57; which has two further connections C and C2. From the connections C and C2 go to lines 58 and 59 to connections ul and B3 of a 4/2-way valve 6o, which has further connections C1 and C3.

Lines 37 and 46 go from these connections C1 and C3 to the storage container 5 off. This persists below the Ilöchstpressure that can be achieved in sub-cycle 1 4/2-way valve 57 in a switching position u, in which all connections are from each other are separated. When the maximum pressure is exceeded, the control line 39 in a switching position v is switched, in which the ports B and C resp. B2 and C2 are connected to each other. Similarly, below the in the sub-cycle 2 reaches ij maximum pressure the 4/2-way valve 60 is held in a switching position w, in which all connections are separated from each other. When the maximum pressure is reached the control line 41 is used to switch to switching position x, in which the connections B1 and C1 or B3 and C3 are connected to one another. To The return of the valves to the initial switching position takes place after a certain pressure drop by springs. In order to reduce the switching frequency, it is also useful here to provide the valves with detents. Since the connections C1 and C3 communicate with each other, it is also possible to use a 3/2-way valve 61, which also has the connections B1 and B3, but has only one connection C4, which is connected to the reservoir 5 is connected.

To explain the function, it is again assumed that the partial cycle 1 reach its maximum pressure earlier than partial cycle 2. Starting out from the switching positions shown are therefore initially both pressure generators 3 and 4 convey into the associated sub-circuits.

As soon as the maximum pressure is reached in sub-circuit 1, over the control lines 13 and 39, the 3/2-way valve 49 and the 4/2-way valve 57 at the same time switched from switching positions q and u to switching positions r and v. the The consequence of this is that the pressure medium is no longer conveyed into the sub-circuit 1 is, but via the overflow line 51 into the sub-circuit 2. A drain in the reservoir is prevented by the fact that the 4/2-way valve 60 is still in the Switching position w remains. If, finally, the maximum pressure in circuit 2 as well is reached, the 3/2-way valve 52 and are via the control lines 21 and 41 the 4/2-way valve 60 from the switching positions s or w into the switching positions t or x switched. The result is that the pressure medium from the pressure generator 4 is now is conveyed into the u flow line 54 and from there via the 4/2-way valves 57 and 60 can flow back into the storage container 5. In the same way, it now takes place since both 4/2-way valves 57 and 60 are switched to throughput, there is also an outflow from the overflow line 51, so that both pressure generators 3 and 4 are almost pressureless support financially. The pressure accumulators 9 and 17 can be emptied through the check valves 50 and 53 prevented. An unacceptably high charge of a partial cycle in those cases in which the pressure of the other tetic circuit is higher than the maximum pressure of the former is prevented by the supply of pressure medium is prevented in the switched-off sub-cycle. By attaching notches Any large switching intervals can also be achieved here.

In Figure 3 is a representational representation of a switching valve 62 shows which the function of a 3/2-way valve and a 4/2-way valve of the type described combined in itself. The 7 connections are the same Reference symbol occupies how the / 2-way valve 49 and the 4/2-way valve 57. Xn in brackets reference numerals are given which are a summary of the 3/2-way valve 52 and the 4/2-way valve 60 correspond. The switching valve 62 does not have a closer illustrated housing 63 in which a bore 64 is made, in the bore 64 slides a control piston 65, which four separated by waists 66, 67 and 68 Has shoulders 69, 70, 71 and 72. The free surface of the shoulder 72 is of a spring 73 is applied. The one adjoining the free end face of the shoulder 69 Room 74 can be connected to the control line 13 or 39 via a connection Z. The shoulders 70, 71 and 72 lock in the switching position brought about by the spring 73 Annular grooves 75, 76 and 77 respectively.

The connection A2 opens into the annular groove 75 Ring groove 76 opens the connection B, and the annular groove 77 finally is with the connection B2 tied together. The waists 66s 67 and 68 are surrounded by annular spaces 78, 79 and 80. The connection P opens into the annular space 78. The annular space 79 is connected to the connection C connected, while the annular space 80 is in communication with the terminal C2. the Shoulder 69 is arranged such that in the starting position of the control piston 65 there is a connection between the annular space 78 and an annular groove 81, which is connected to the connection A, The shoulder 65 has two axially separated from each other Grooves 82 and 83 into which a ball and spring detent 84 can intervene. It is very easy to see that the connection P is in the starting position of the control piston 65 with the connection A via the annular space 78 and the annular groove 81 connected is.

The connection P is separated from the connection A by the shoulder 70. The shoulder 71 separates the ports B and C, while the shoulder 65 separates the ports B2 and C2 separates from each other. When the space 74 is subjected to a pressure in The control piston 46 becomes the height of the maximum pressure with the torsion of the spring 73 and of the detent 84 is switched into a second switching position in which the detent 84 in the annular groove 82 e engages. In this switching position the connection P is from the connection. A separated by the shoulder 69 and connected to the connection A2 via the annular space 78 and the annular groove 75 connected. The connection B is via the annular groove 76 and the annular space 79 connected to the port C, while the port B2 over the Annular groove 77 and the annular space 80 is in communication with the connection C2. on the other hand are the connections A2 and C and B and C2 by the shoulders 70 and 71 from each other separated. The function of the switching valve 62 thus fully corresponds to the switching functions of the valves symbolically shown in FIG.

Of course, the bias of the spring 73 can, although not shown, adjustable in their 1höhe by adjusting devices of any kind be made.

Claims (4)

Patent claims: y) / 1st hydraulic circuit with two, in particular with pressure accumulators provided subcircuits and printer generators assigned to these subcircuits as well as check valves and pressure-actuated switching valves, which. upon reaching a preselectable maximum pressure in a partial circuit there is a further pressure increase prevent, characterized in that each pressure generator (3, 4) has a valve arrangement (7.25; 15.31; 49; 52) is assigned, which is below a maximum pressure in a switching position (a, e; c, g; q, s) effected by spring force or the like (P - A, P1 - A1) between the pressure generator (3, 4) and the one assigned to the pressure generator (3, 4) Tejikreifllauf (1,2) causes and when the highest pressure is reached by application with the pressure of the sub-circuit (1,2) against the spring force in a switching position (b, f; d, h; r1t) switches, in which said connection (P - A, P1 - A1) is blocked and another connection (P2 - A2, P3 - A3 o P - A2 t P1 - A3) from the pressure generator (3,4) to an overflow line (line branches 23,24; 29,30; 41,54) to the other Partial circuit (1,2) is opened, with each overflow line (line branches 23.24; 29.30; 51,54) via a first (34,43; 57) and a second (36t45; 6o) to the first (34.43; 57) on-off valve connected in series with one system Lower pressure (reservoir 5) can be connected and one of the open-close valves (34.43; 57) at the maximum pressure of the first partial circuit (1) and the other (36.4; 6o) at the maximum pressure of the second tilting circuit (2) switched to the "open" switch position be, with an outflow of pressure medium from the sub-circuit (1,2) into the system low pressure (reservoir 5) prevented by check valves (26,32,50,53) will. 2. Hydraulic circuit according to claim 1, characterized in that that the valve assembly consists of two on-off valves lenf7,25il5,31) of which one is in the "closed" position when the other is in the "open" position stands. 3. Hydraulic circuit according to claim 1, characterized gekennzeiclinet, that the valve arrangement has the function of a pressure-switched 3/2-way valve (4'3,52) possesses, which in its first switching position (q, s) initiates the pressure generator (3, 4) the partial circuit (1,2> connects and the overflow line (51,54) blocks and in a second switching position (r, t) when the maximum pressure is reached, the partial circuit (1,2) shut off and the pressure generator (3,4) with the overcurrent line <51,54) connects. 4. Ilydraulic circuit according to one or more of the preceding claims, characterized in that the first and second open-close valves in each case Connections (55,58, 37; 56,59,46) between the overflow lines (51,54) and the System of lower pressure (reservoir 5) combined into 4/2-way valves (57, 60) which in a first switching position (u, w) all connections (B, C, B2, C2; C1, B3, C3) separate from each other and in a second switch position (v, x), each connections (B - C, B2 - C23 B1 - C1, C3). Blank page