JPS5845603B2 - Device for adjusting the amount of work of a servo motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits have a switching mechanism ( control valve)
selectively via a supply conduit connected to a pressure medium source or to a return circuit, in this case a first throttle mechanism adjustable for the return flow from the servo motor; A pressure-related pressure reducing valve is operative upstream of the mechanism, the regulating member of which is removed in one direction between the pressure reducing valve and the first throttle mechanism; It concerns a type that is loaded by a pilot pressure formed in a first pressure chamber and in the other direction by a setpoint spring and a pressure formed in a second pressure chamber.

In the known device of the type described (German Patent Application No. 192 2 073), the throttle mechanism and the pressure reducing valve connected upstream of this throttle mechanism are arranged in one motor connection line and in the supply direction. It is bridged by a check valve that opens at

In addition to the setpoint spring, the regulating element of the pressure reducing valve is loaded by the pressure across the throttle mechanism.

The pressure reducing valve maintains a pressure gradient across the throttling mechanism, thereby keeping the flow rate and the speed at which the servo motor is driven constant depending on the end result.

The speed of movement is maintained constantly even when an external force is applied to the servo motor.

If such an adjustment in connection with the throttle takes place in the return circuit, a pressure gradient is created, which increases the pressure level of the servo motor.

Therefore, the servo motor is constantly loaded with high pressure during operation, and the leakage losses are correspondingly large.

Furthermore, it is known to arrange an adjustable throttle mechanism in a supply line with a regulating valve that constantly maintains the pressure gradient across the throttle mechanism (German Patent Application No. 1,650,315).

However, in this case, the external force acting on the servo motor causes a change in the speed of movement and, in some cases, a cavitation phenomenon.

Furthermore, it is known to arrange a pressure reducing valve in each branch of the quantity distributor before and after the throttle mechanism in the quantity distributor used in both flow directions (German Patent Application Publication no. 1206610).

In this case, the downstream pressure reducing valve in each case does not function because the setpoint spring is assisted by the high pressure; however, the circuit operates in relation to the flow direction and acts on the servomotor. Do not work in conjunction with external loads.

The object of the invention is to combine the advantages of a throttle mechanism arranged in the return line with the advantages of a throttle mechanism arranged in the supply line together with the pressure reducing valve.

According to the first invention, the above-mentioned problem is solved by the first invention.
An adjustable second throttle mechanism is arranged in conjunction with the throttle mechanism, and the pressure in the second pressure chamber is extracted between the second throttle mechanism and the servo motor. It was done.

In the case of the circuit described, the pressure reducing valve is brought into the open position during normal operation, so that the pressure gradients that occur across the pressure reducing valve are very small.

This is because the setpoint spring is relatively thick and is supported by a pressure which is usually equal to the working pressure on the supply side of the servo motor.

However, if an external load acts on the servomotor in the working direction and this causes a drop in the pressure in the supply line, the pressure reducing valve moves into a throttle position which prevents a rapid outflow of the return quantity.

This applies in particular if undesirably low pressures occur on the feed side, which can lead to cavitation.

The switching therefore takes place automatically.

During normal operation, i.e. in the case of normal high pressures, the pressure in the servo motor is not increased by the pressure gradient at the pressure reducing valve, whereas in the event of a fault, i.e. in the case of an external load, the pressure in the servo motor is not increased by the pressure gradient at the pressure reducing valve. The valve immediately moves to the desired throttle position.

Furthermore, the above-mentioned problem can be solved according to the second invention, in which an adjustable second throttling mechanism interlocking with the first throttling mechanism is arranged in the supply conduit, and the pressure in the second pressure chamber is adjusted to the second throttling mechanism. A regulating valve is provided between the throttle mechanism and the servo motor and connected in series with the second throttle mechanism, and the regulating valve adjusts the pressure gradient in the second throttle mechanism. This was resolved by keeping it constant.

With this configuration, the working amount of the servomotor is kept constant even if the pressure reducing valve acting on the return is fully opened during normal operation.

Furthermore, the above-mentioned problem can be solved according to the third invention, in which an adjustable second throttle mechanism that interlocks with the first throttle mechanism is disposed in the supply conduit, and the pressure in the second pressure chamber is adjusted to a second level. A pressure reducing valve is arranged in one of the motor connection conduits, and a second throttle mechanism is arranged in the second pressure chamber at each working position. The solution is that a switchable control path is provided for supplying the pressure between the motor and the servo motor.

Such an arrangement makes it possible to otherwise disable the pressure reducing valve, i.e. to keep it permanently open if the pressure reducing valve is located in the supply conduit. Functions can be disabled.

For this purpose, if the pressure reducing valve is located in the supply conduit, the second pressure chamber of the pressure reducing valve is loaded with the same pressure as the first pressure chamber.

In this case, the pressure reducing valve is moved into the open position under the action of the setpoint value setting spring.

Furthermore, the above-mentioned problem can be solved according to a fourth aspect of the present invention, in which an adjustable second throttle mechanism that is interlocked with the first throttle mechanism is disposed within the supply conduit, and the pressure in the second pressure chamber is adjusted to a second level. The problem is solved by providing a pressure reducing valve between the throttle mechanism and the servo motor, and one pressure reducing valve is provided in each of the two motor connecting conduits.

Such an arrangement is particularly suitable if a negative load acts in the direction of circular movement of the motor, for example in the case of a rudder.

Furthermore, the above-mentioned problem can be solved according to a fifth aspect of the invention, in which an adjustable second throttle mechanism interlocking with the first throttle mechanism is disposed in the supply conduit, and the pressure in the second pressure chamber is adjusted to a second level. The solution is that it is taken out between the throttle mechanism and the servomotor, and that both throttle mechanisms each have approximately the same open cross section.

Such an arrangement creates a unique relationship and makes it possible to exchange the first throttle mechanism and the second throttle mechanism during reverse operation.

Furthermore, the above-mentioned problem can be solved according to the sixth invention, in which an adjustable second throttle mechanism that interlocks with the first throttle mechanism is disposed in the supply conduit, and the pressure in the second pressure chamber is adjusted to the second level. A regulating valve is provided between the throttle mechanism and the servo motor and connected in series with the second throttle mechanism, and the regulating valve adjusts the pressure gradient in the second throttle mechanism. the pressure gradient in the first throttling mechanism, regulated by the pressure reducing valve, and the pressure gradient in the second throttling mechanism defined by the regulating valve; It was solved by being designed to be the same.

This arrangement ensures that the pressure between the first throttling mechanism and the servo motor never drops below the tank pressure, ie that cavitation phenomena do not occur.

This is because in the case of a negative load, more liquid is prevented from flowing out of the servo motor than towards it.

The same advantages can also be obtained if the opening cross-sections of the two throttle mechanisms are different, provided that the pressure gradient is appropriately calculated.

Furthermore, the problem can be solved according to the seventh invention, in which an adjustable second throttle mechanism that interlocks with the first throttle mechanism is disposed in the supply conduit, and the pressure in the second pressure chamber is adjusted to a second level. between the throttle mechanism and the servo motor, and the first throttle mechanism and the second throttle mechanism are integrated into a four-way valve with an intermediate position having a throttle action. Resolved.

In the case of such valves, the synchronicity of the opening cross section is guaranteed in a simple manner.

Furthermore, the above-mentioned problem is solved according to the eighth invention, in which an adjustable second throttle mechanism interlocking with the first throttle mechanism is disposed in the supply conduit, and the pressure in the second pressure chamber is adjusted to the second throttle mechanism. the first throttle mechanism and the second throttle mechanism are integrated into a four-way valve with an intermediate position having a throttle action;
Furthermore, the four-way valve is used as a switching mechanism and has a switchable control channel.

Such an arrangement simplifies the structure even further.

The invention will now be explained with reference to the illustrated embodiment.

In the embodiment according to FIG. 1, a servomotor 32 is provided which has a cylinder 33 and a piston 34, which piston 34 is loaded by an external load body.

Two motor connection lines 35, 36 are therefore also provided, which are each connected to tank line 23 via a safety valve 37, 38.

For filling, the motor connection line 36 is connected to the tank line 23 via a check valve 39 .

The motor connection conduit 35 is connected via the pressure reducing valve 9 to the connection element 40 of the four-way switching valve 42, and the motor connection line 36 is directly connected to the connection element 41 of the four-way switching valve 42.
This four-way switching valve 42 is adjustable via a manual lever 43.

First throttling mechanism 10 or 1 for return for each driving direction
0' and a second supply throttling mechanism 44 or 44'.

Both aperture mechanisms 10.1σ. 44, 44' are adjustable together.

The throttle mechanism has the same open cross section in pairs for working position b (adjusting distance X) and working position C (adjusting distance y).

Furthermore, a neutral position a is provided. A pump 6 with a pump pressure Pp is used as a source of pressure medium, said pump 6
A safety valve 29 is assigned to.

This safety valve 29 is opened when a predetermined pump pressure is exceeded.

Pump 6 conveys pressurized liquid from tank 11 via supply conduit 7 to four-way switching valve 42 .

A regulating valve 21 is provided in the supply line 7, which is loaded on the one hand by the pressure Pr in the supply line T and on the other hand by the setpoint spring 28 and the pressure in the line 24.

The pressure reducing valve 9 in one motor connection conduit 35 has a first pressure chamber 15 and a second pressure chamber 17, and the first pressure chamber 15 has a pressure reducing valve 9 and a throttle mechanism 10, 10'. the four-way switching valve 42 having a second
The second pressure chamber 17 is connected to the conduit 24 and the pressure in the second pressure chamber 17 acts in the same direction as the setpoint spring 18 .

The second pressure chamber 17 and the conduit 24 are located at the neutral position a.
A throttle 44 which is connected to the tank line 23 conducting the tank pressure pt via a control line 25 in the directional valve 42 and which carries the pressure Pd via the control line 26 in each of the two working positions c, c. , 44'.

The operation mode for the embodiment shown in FIG. 1 is as follows.

If the four-way switching valve 42 is moved to the working position by the adjustment distance

It flows into the left side of the servo motor 32 via the pressure reducing valve 9.

At the same time, pressure medium flows through the first throttle mechanism 10' towards the tank.

A pressure Pd is applied to the second pressure chamber 17 and the conduit 24 via the control passage 26 .

The pressure reducing valve 9 is therefore completely opened by the setpoint setting spring 18.

Pressure regulating valve 21 maintains a constant pressure gradient at four-way switching valve 42.

The supply amount is therefore determined by the adjustment distance X and by the throttle mechanism 44.
is defined by a suitable aperture aperture within '.

If the four-way switching valve 42 is moved to the working position C by the adjustment distance y, the supplied pressure liquid is forced to flow directly to the right side of the servo motor 32 via the throttle mechanism 44 .

At the same time, the second pressure chamber 17 of the pressure reducing valve 9 is again supplied with the pressure Pd, whereas the pressure Ps at point 16 is regulated by the pressure reducing valve 9.

The returned pressure liquid now flows through the regulated pressure reducing valve 9 and then through the adjustable throttling mechanism 10.

When there is no negative load, the pressure Pd in the second pressure chamber 17 is significantly greater than the pressure Ps in the first pressure chamber 15.

Therefore, the pressure reducing valve 9 is completely opened and the amount of work is performed only by the throttling mechanism 44.

However, if the negative load becomes large, the pressure Pd is reduced until the pressure Ps finally becomes large enough to move the pressure reducing valve 9 in the closing direction.

This causes a restriction in the amount of return. Controlled operation within the supply conduit is thus maintained.

However, if the pressure in the connecting conduit 36 is reduced due to the negative load so that it can no longer be controlled on the supply side, the pressure Ps is kept constant by the pressure reducing valve 9 and the flow is now the second pressure chamber 1 such that overload control is produced by the throttling mechanism 10;
The pressure inside 7 is also reduced.

The mode of action can be seen more precisely from the numerical examples below.

Aperture mechanism 44 or 41/! The pressure gradient across is kept constant at 4 bar using a regulating valve 21, the load is equal to a pressure of 200 bar, the cross section of the cylinder is twice as large on the left as on the right, and the target value setting Spring 1
8 exerts a pressure of 3 bar and the throttling mechanism 10, 44
Alternatively, assume that 10' and 44' have the same opening in pairs.

Furthermore, the adjustment is such that the pressure liquid of 51 per unit time is controlled by the throttling mechanism 4.
4'.

(a) If the four-way valve 42 is moved into the working position, the pressure gradient at the throttle mechanism 10' is determined to be 1 bar.

If the tank pressure is equal to O bar, then the pressure P
s becomes 201 bar and the pump pressure becomes 204 bar.

(b) If the four-way valve 42 is moved into the working position C, the pressure gradient in the throttle mechanism 10 is calculated to be 16 bar.

Since said pressure is the same as the constant pressure generated by the setpoint spring 18 plus the pressure Pd in the supply line, said pressure Pd is calculated to be 13 bar, and thus the pump pressure Pp is calculated to be 17 bar. .

In the embodiment according to FIG. 2, only the circuit parts which are located above the four-way switching valve 47 are shown in the drawing.

In this exemplary embodiment, the two connecting lines 35, 36 are connected to the associated connecting elements 40, 41 via a pressure reducing valve 9 or γ.

Both pressure reducing valves are bridged by check valves 45, 45', each of which opens towards the servo motor 32.

The first pressure chamber 15 is connected to the point 16 and the first pressure chamber 15'
is connected to point 16'.

The second pressure chamber 17 is connected to the connecting element 41 or the motor connecting conduit 36 at point 46, and the second pressure chamber 17' is connected to the connecting element 40 or the motor connecting conduit 35 at point 4''.
is connected to.

If the connecting element 41 conducts the supply pressure, the servo motor 32 is supplied via the check valve 45'.

The pressure reducing valve 9 is configured such that the pressure liquid flows out unhindered.
Moved to open position.

Only if the load is too large and the pressure in the connecting member 41 drops, the pressure reducing valve 9 will act in the manner described above with a throttling action.

The same applies correspondingly for the adjustment of the motor 32 in the opposite direction when an external load acts in the opposite direction.

Instead of the check valves 45, 45', it is also possible to use pressure reducing valves 9, 9' which are controlled via a four-way switching valve 42, depending on the type of pressure reducing valve 9 according to FIG.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG.
Figure 2, a circuit diagram for a double-acting servo motor subjected to negative loads in only one direction, is a circuit diagram of Figure 1 with a double-acting servo motor subjected to negative loads in both directions. It is a diagram of a modified example. 6...pump, 7...supply conduit, 9,
9/...Reducing valve, 10, 10'...-First throttling mechanism, 11...Tank, 15, 15'
...First pressure chamber, 16°16'...
Point, 17, 17'...Second pressure chamber, 18°1
8'... Target setting spring, 21... Pressure regulating valve, 23... Tank conduit, 24...
・Conduit, 25, 26... Control passage, 27...
...Point, 28...Target value setting spring, 29...
... Safety valve, 32 ... Servo motor, 33
......Cylinder, 34...Piston, 3
5゜36... Motor connection conduit, 37, 38...
...Safety valve, 39...Check valve, 40,41
......Connection member, 42...Four-way switching valve, 43...Curved manual lever, 44°44'...
Second throttling mechanism, 45, 45'■...Check valve, 46.4
6'...point, a...neutral position, b, c
...One working position, L...Load, Pd, P
s, Pr------Pressure, Pp------Pump pressure, pt---Tank pressure, E, y------
Adjustment distance.

Claims (1)

[Scope of Claims] 1. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits have a switching mechanism (control valve). a first throttling mechanism which can be optionally connected to a supply conduit connected to a source of pressure medium or to a return circuit via which the flow can be adjusted for the return flow from the servomotor; A first pressure-reducing valve, which is actuated in the upstream in relation to the pressure, and whose regulating member can be taken out in one direction between the pressure-reducing valve and the first throttle mechanism; a first throttle mechanism in the supply conduit, loaded in the other direction by a setpoint spring and a pressure created in a second pressure chamber; Adjustable second throttle mechanisms 44, 44' that interlock with the second throttle mechanisms 44, 44' and the servo motor 32 are disposed so that the pressure Pd in the second pressure chamber 17 is controlled by the second throttle mechanisms 44, 44' and the servo motor 32. A device for adjusting the amount of work of a servo motor, characterized in that the amount of work is adjusted to be taken out between the servo motors. 2. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits are selectively operated via a switching mechanism (control valve). A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit and in this case adjustable for the return flow from the supporting motor, and upstream of this throttling mechanism, a pressure-related a controlled pressure reducing valve is operative, the regulating member of the pressure reducing valve being withdrawn in one direction between the pressure reducing valve and the first throttle mechanism;
of the type which is loaded by a pilot pressure created in a first pressure chamber and in the other direction by a setpoint spring and a pressure created in a second pressure chamber, a first Adjustable second throttle mechanisms 44, 44' that interlock with the throttle mechanisms 10, 10' are arranged, and the pressure Pd in the second pressure chamber 17 is controlled by the second throttle mechanisms 44, 44' and the servo motor. 32, and is further provided with a regulating valve 21 connected in series with the second throttling mechanism 44, 44', and this regulating valve 21 controls the pressure in the second throttling mechanism. A device for adjusting the amount of work of a servo motor, characterized in that the slope is maintained constantly. 3. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits are selectively operated via a switching mechanism (control valve). A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit, in this case adjustable for the return flow from the servomotor, and upstream of this throttling mechanism, a pressure-related a pressure-reducing valve controlled by the pressure-reducing valve is formed in a first pressure chamber, the regulating member of which is taken out in one direction between the pressure-reducing valve and the first throttle mechanism; in the supply conduit in conjunction with the first throttle mechanism 10, 10', which is loaded by a pilot pressure in the supply line and in the other direction by the setpoint spring and the pressure created in the second pressure chamber. A second adjustable throttle mechanism 44, 44' is arranged such that the pressure Pd in the second pressure chamber 17 is extracted between the second throttle mechanism 44, 44' and the servo motor 32. Furthermore, a pressure reducing valve is arranged in one of the motor connecting conduits, and furthermore, each working position is
A servo motor characterized in that a switchable section side passage 26 is provided in the second pressure chamber 17 for supplying the pressure Pd between the second throttle mechanism 44, 44' and the servo motor 32. A device for adjusting the amount of work. 4. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits are selectively operated via a switching mechanism (control valve). A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit, in this case adjustable for the return flow from the servomotor, and upstream of this throttling mechanism, a pressure-related a pressure-reducing valve controlled by the pressure-reducing valve is formed in a first pressure chamber, the regulating member of which is taken out in one direction between the pressure-reducing valve and the first throttle mechanism; a first throttle mechanism 10,1σ in the supply conduit, which is loaded in the other direction by a setpoint spring and by the pressure created in the second pressure chamber; An adjustable second throttle mechanism 44 , 44 ′ is arranged such that the pressure Pd in the second pressure chamber 17 is extracted between the second throttle mechanism 44 , 44 ′ and the servo motor 32 . Furthermore, both motor connection conduits 35, 3
A device for adjusting the working amount of a servo motor, characterized in that one pressure reducing valve 9, 9' is provided in each of the servo motors 6. 5. A device for adjusting the working amount of a motor motor, wherein the servo motor has two motor connection conduits, in which the pressure is selectively adjusted via a switching mechanism (control valve). A first throttling mechanism connectable to the supply conduit connected to the medium source or to the return circuit, in this case adjustable for the return flow from the servomotor, and upstream of this throttling mechanism in connection with the pressure. a controlled pressure reducing valve is formed in a first pressure chamber adapted to act, the regulating member of which is taken out in one direction between the pressure reducing valve and the first throttle mechanism; A first throttle mechanism 10, 10' is associated in the supply conduit, in the version which is loaded by the pilot pressure and in the other direction by the setpoint spring and the pressure created in the second pressure chamber. An adjustable second throttle mechanism 44 , 44 ′ is arranged such that the pressure Pd in the second pressure chamber 17 is extracted between the second throttle mechanism 44 , 44 ′ and the servo motor 32 . Furthermore, both aperture mechanisms are 10°44;
Device for adjusting the working rate of a servo motor, characterized in that 10', 44' each have approximately the same open cross section. 6. A device for adjusting the amount of work of a servo motor, the servo motor having two motor connection conduits, and selectively controlling the amount of work of a servo motor via a switching mechanism (control valve) of the motor connection conduits. A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit, in this case adjustable for the return flow from the servomotor, and upstream of this throttling mechanism, a pressure-related a pressure-reducing valve controlled by the pressure-reducing valve, in which the regulating member of the pressure-reducing valve is taken out in one direction between the pressure-reducing valve and the first throttle mechanism; In the version in which the pressure is applied in the other direction by the setpoint pressure and in the second pressure chamber by the setpoint pressure and the pressure created in the second pressure chamber, a first throttling mechanism 10 is provided in the supply conduit. , 10' are arranged, and the pressure Pd in the second pressure chamber 17 is adjusted between the second throttle mechanisms 44, 44' and the servo motor 32. It is designed to be taken out between the
A regulating valve 21 is provided in series with the pressure reducing valve 9 to maintain the pressure gradient in the second throttling mechanism constantly. First throttling mechanism 1 regulated by a valve
Work volume of a servomotor, characterized in that it is designed such that the pressure gradient at 0, 10' is at most the same as the pressure gradient at the second throttling mechanism 44, 44', defined by the regulating valve 21. A device for adjusting. 7. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits are selectively operated via a switching mechanism (control valve). A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit, in this case adjustable for the return flow from the servomotor, and upstream of this throttling mechanism, a pressure-related a pressure-reducing valve controlled by the pressure-reducing valve is formed in a first pressure chamber, the regulating member of which is taken out in one direction between the pressure-reducing valve and the first throttle mechanism; a first throttle mechanism 10,1σ in the supply conduit, which is loaded in the other direction by a setpoint spring and by the pressure established in the second pressure chamber; An adjustable second throttle mechanism 44.44' is arranged such that the pressure Pd in the second pressure chamber 17 is taken off between the second throttle mechanism 44.44' and the servo motor 32. The servo is further characterized in that the first throttling mechanism 10°10' and the second throttling mechanism 44, 44' are integrated into a four-way valve 42 with an intermediate position having a throttling action. A device for adjusting the amount of work of the motor. 8. A device for adjusting the amount of work of a servo motor, wherein the servo motor has two motor connection conduits, and the motor connection conduits are selectively operated via a switching mechanism (control valve). A first throttling mechanism, which can be connected to a supply line connected to a pressure medium source or to a return circuit and in this case adjustable for the return flow from the servomotor, and a pressure-related throttle upstream of this throttling mechanism, are provided. a pressure-reducing valve controlled by the pressure-reducing valve is adapted to act, the regulating member of the pressure-reducing valve being formed in a first pressure chamber which is taken out in one direction between the pressure-reducing valve and the first throttle mechanism; in the supply conduit in conjunction with a first throttling mechanism 10, 10', which is loaded by a pilot pressure in the supply line and in the other direction by a setpoint spring and by the pressure created in the second pressure chamber. Adjustable second throttle mechanisms 44, 44' are arranged so that the pressure Pd in the second pressure chamber 17 is taken out between the second throttle mechanisms 44, 44 and the servo motor 32. Further, the first throttle mechanism 10°1σ and the second throttle mechanism 44, 44' are integrated into a four-way valve 42 with an intermediate position having a throttle action, and the four-way valve 42 is the switching mechanism 10°44.1ff, 44'
Device for adjusting the working amount of a servo motor, characterized in that it is used as a servo motor and has a switchable control channel 26.