DE2257213B2 - 3- or 4-way solenoid valve - Google Patents

Description

The invention relates to a 3 or 4-way solenoid valve, in which the armature is held in its one end position by means of a first spring, in which a connected to the anchor first closure piece closes one connection, and br: the through the By force of an electromagnet, the armature can be displaced into a second position in which the first locking piece is lifted from its valve seat and in which a second closure piece connected to the armature blocks the second connection, in which the locking pieces continue relative to the armature in the axial direction the same are movable against spring forces acting in the direction of the valve seats and at which is also provided for each of the two locking pieces on the anchor. of which respectively one enters into engagement with a locking piece before reaching an anchor end position and the locking piece lifts off his seat.

Such solenoid valves are z. B. from DE-OS 1815717 and US-PS 3043336 known. With these Two-position valves, the locking pieces are movably mounted in the axial direction on the armature to prevent possible To be able to compensate for tolerances.

Such valves are used, among other applications, in the field of anti-lock regulators. You are there z. B. switched into the brake line in such a way that in the unexcited state the brake line is permeable. If there is a tendency to block, the valve is switched and then connects to lower the pressure the wheel brake cylinder on the wheel brake with a return line (see e.g. DE-OS 1914765, Fig. 3).

With many anti-lock control systems, however, in addition to the pressure build-up states and

Pressure reduction also a phase in which the pressure is kept constant. To realize this state, in which the brake line is interrupted, but the wheel brake cylinder is not connected to the return line is connected, two two-way valves have been used so far, namely one switched on in the brake line, normally open inlet valve and a between the wheel brake cylinder and the return line tion switched on, normally closed outlet valve (see e.g. DE-OS 1914765, Fig. 1).

To enable the third pressure state (keeping the pressure constant) it is from the DE-OS 1914765 also known to apply pulses to the three-way valve, with the corresponding Choice of the pulse duty factor of the pulse train a brake pressure that is constant on average is achieved.

The object on which the invention is based is to create a 3 or 4-way valve which can be controlled in three different positions and thus various options for influencing the pressure allowed and with which the effort for the control in these three positions is small.

This object is achieved according to the invention by the features specified in claim 1.

According to the invention, the known three-way valve becomes a valve with an intermediate position redesigned in which both lockable connections are completed. The one needed for this Additional effort is insignificant. When using four connections, the invention additionally a condition is created in which the two separate valves are closed.

In the valve according to the invention, the control force is generated by means of a winding.

According to one embodiment of the invention, the additional, the intermediate position is determined Spring inserted into the armature, one end of which rests against a stop that starts from the intermediate position of the valve is moved by one of the closure pieces against the force of the spring.

The two spring forces acting on the closure pieces can, according to one embodiment can be generated by a common spring.

The valve can be brought into the two excited positions by different excitation currents. According to a preferred embodiment, the excitation in the intermediate position is achieved by means of pulses Reached clock ratio, which must be chosen so that on the one hand in the pulse pauses no valve drop is caused and, on the other hand, the valve does not reach the end position. You can Generate impulses for this in various ways. Also, monitoring circuits are correct Adjustment of the valve provided.

Exemplary embodiments of the invention are explained in more detail with reference to the drawings. It shows

Fig. 1 is a schematic diagram of an embodiment according to the invention,

Fig. 2 shows a possible construction of the inventive Semäß Solenoid valve,

Fig. 3 to 5 control circuits for the valve,

6 and 7 monitoring circuits for the valve.

In the embodiment of FIG. 1, the valve housing is 1, the excitation winding is 2, the armature with 3 and the two locking pieces with 4 and 5. When used in an anti-lock regulator the hydraulic connection 6 is connected to the main

brake cylinder, connection 7 with the wheel brake cylinder and connection 8 with the return line tied together. The spring 9 holds the armature in the initial position shown. The two locking pieces 4 and 5 are movable relative to the armature in the direction of the axis of the armature. The springs 10 and 11 try to press the extensions 12 and 13 of the locking pieces against the catches 14 and 15. The stop 16 can be moved to the left against the force of the spring 17. He lies in the drawn Position on anchor 3.

In the illustrated starting position of the armature, the connection 6 is connected to the connection via the opening 18 7 connected. The locking piece 4, which is under the pressure of the spring 10, closes the connection 8 from. If a current suitable for reaching the intermediate position is applied to the winding, so the armature 3 moves to the right. The closure piece 5 comes on the valve seat of the Connection ό to the system and the spring 11 is tensioned until the extension 13 of the closure piece comes to rest against the stop 16. Daa through the The magnetic field caused by the control current is no longer able to hold the armature against the egg Force of the spring 17 to move, d. H. the valve has reached its intermediate position. Since the anchor movement the closure piece 4 could move relative to the armature 3 due to the spring 10, is the Port 8 is still closed.

If the current in the winding 2 is increased, the armature 3 moves further to the right, with one Relative movement between the armature 3 and the closure piece 5 including the stop 16 comes about comes. On the other hand, however, the closure piece 4 is now removed from the anchor by the entrainment 14 3 and thus the connection 8 is connected to the connection 7.

2a shows a section through a preferred embodiment of the invention. The valve body is denoted here with 1 ', the excitation coil with 2' and the armature with 3 '. The hydraulic connections 6 to 8 corresponding connections are denoted by 6 'to 8'. The locking pieces are with 4 ' and 5 'denotes. The spring pressure on the locking pieces is achieved by the common spring 10 ' evoked. The spring 9 'holds the armature in the position shown.

The locking pieces 4 'and 5' can, as FIG. 2a shows at points 21 and 22, in the axial direction of the armature 3 'and move relative to it. The illustrated position of the locking pieces is with respect to of the closure piece 4 'through the valve seat of the connection 8' and the stop 23 'and with respect to of the Vei-ichlußstücks 5 'by the entrainment 15' and caused the spring 10 '.

If the valve is now excited with the small power, so the armature 3 moves to the left, whereby the closure piece 5 'on the valve seat of the connection 6 comes to the plant. The movement stops when the stop, which is movable relative to the armature 3 16 'comes to rest on the closure piece 5', since the force of the electromagnet is also insufficient to overcome the force of the spring 17 ', which holds the stop 16' in the position shown. The position Fig. 2b shows the individual parts to one another in the intermediate position.

If the excitation is increased further, the armature is moved further to litIKS, whereby the stop 16 'moves

moved against the spring force of the spring 17 'relative to the armature 3 until the movable stop 16' on Stop 24 comes to the system. During this movement from the intermediate position to the end position, the Carriage 14 ', the locking piece 4' taken and the connection 8 'opened. The end position shows Fig. c.

In addition to the mentioned possibilities of valve control in the intermediate position by means of a correspondingly dimensioned current or a corresponding winding, the possibility of control with pulses was also mentioned. This method also has the advantage that a second power amplifier can be dispensed with. It is more favorable to use a circuit that determines the clock ratio itself than a predefined clock ratio. For this purpose, three embodiments are shown in the drawing with cni «>l«> αηοραρΚρη "I Oe

In the exemplary embodiment in FIG. 3, the signal for controlling the intermediate position at E and that for controlling the (excited) end position at A is fed. Both tensions are assumed to be equal. Via the OR gate 25 and the common power amplifier 26, these signals reach the valve winding 27. After the time necessary for the response, the armature moves via the intermediate position into the end position when the control signal is present from A. This signal is not influenced by the comparison circuit 28 and the timing element 29. If, on the other hand, the signal for setting the intermediate position occurs at E , this signal is blocked via the AND gate 30 with inverted input for a time specified by the timing element 29 as soon as the voltage tapped at the resistor 31 and corresponding to the valve current exceeds a predetermined voltage value which is applied to the terminal 32 of the comparison circuit 28. This voltage value is selected so that the intermediate position is safely reached, but the end position is not reached. The time given by the timing element 29 must be chosen so that the control signal is not blocked for too long and the armature therefore returns to its starting position.

The embodiment of FIG. 4 differs from that of FIG. 3 only in that the comparison circuit 28 'can still be switched to a lower comparison value U ₀ and that this switchover is carried out when an output signal of the comparison circuit occurs. This means that the AND gate 30 is blocked (pulse pause) as soon as the upper comparison voltage value U. is exceeded by the voltage at the valve, and that this blocking is maintained until the lower comparison voltage value U _{0 is} reached.

In the embodiment of Fig. 5, the blocking of the signal at E is effected via the AND gate 30 by a switch 33 which is arranged in the valve and responds as soon as the armature reaches the intermediate position. If the armature wants to move back into the starting position, the switch opens again immediately and again applies voltage to the valve 27.

The circuit of FIG. 6 is used to monitor the intermediate valve position. In this, the controlled pressure must not change due to the valve position. Therefore, in addition to the voltage of a pressure sensor that is connected to terminal 34, there is also the? .5 Aiieeanossianal Ae.% Hiese voltage differentiating differentiator 35 and the signal for the control of the intermediate position to the AND gate 36, which thus the warning lamp 37 lights up when a pressure change is taking place with an existing control signal and an existing pressure.

7 shows a further circuit for monitoring the correct setting of the valve in the intermediate position. The signal fed to the valve for the setting into the intermediate position is also fed to an electrical memory 38, to which the voltage of a pressure sensor 39 is applied, which is thus stored when the valve control signal occurs. The pressure sensor is located in the pressure regulated by the valve and generates a voltage corresponding to this pressure. After the occurrence of the valve control signal E, there may no longer be any pressure changes due to the valve position. If this is the case, the valve has wrongly not responded. This is determined in the comparison element 40, where the stored voltage corresponding to the pressure when the E signal occurs is compared with the voltage corresponding to the instantaneous pressure. If the pressure changes by a predetermined amount, the comparison element 40 emits a voltage which is used to control the valve in the end position (as an additional ^ signal), so that the pressure in the version with three connections is reduced. On the basis of the comparison element 40, there is then ongoing switching back and forth between the end positions of the valve.

For this purpose 3 sheets of drawings

Claims (9)

Patent claims: 1. 3- or 4-way solenoid valve, in which the armature by means of a first spring in its one The end position is held in which a first closure piece connected to the armature has one connection shut off, and the armature in a second position by the force of an electromagnet is displaceable, in which the first closure piece is lifted from its valve seat and in a second, connected to the armature locking piece blocks the second connection, in which continue the locking pieces relative to the anchor in the axial direction of the same opposite in the direction spring forces acting on the valve seats are movable and in the case of the further for the two Closure pieces on the anchor are each provided with a driver, one of which is before reaching an anchor position with a locking piece engages and the locking piece of his Seat lifts off, characterized in that a) the valve has a third intermediate position between the two end positions has, in which both locking pieces (4, S) sit on their valve seats, b) from the intermediate position when moving into the second end position, a further spring force is effective on the armature (3) in the sense of a restoring force and c) the winding (2) of the electromagnet for setting in the intermediate and in the second end position with different performance determined by the spring forces can be acted upon. 2. Solenoid valve according to claim 1, characterized in that a prestressed in the armature (3) Spring (17) is used, which rests with one end against a stop (16) which from the intermediate position of the valve from one (5) of the closure piece (4, 5) against the force of the spring is moved. 3. Solenoid valve according to one of claims 1 to 4, characterized in that for generation a common spring (10 ') is provided for the spring forces on the two closure bodies (4', 5 ') is. 4. Solenoid valve according to one of claims 1 to 3, characterized in that the winding (2) for setting into the intermediate position with pulses with a correspondingly dimensioned cycle ratio is controllable. 5. Solenoid valve according to claim 4, characterized in that a comparison circuit (28) is provided, the one proportional to the valve current Voltage and a constant comparison voltage (32) is supplied, and that switching means (29,30) are provided which are exceeded when i the comparison voltage is a signal for the temporary interruption of the intermediate position controlling Generate signal. 6. Solenoid valve according to claim 5, characterized in that the comparison circuit (28 ') can also be switched to a smaller comparison value ( U _n ) which is effective when an output signal of the comparison circuit occurs. 7. Solenoid valve according to claim 4, characterized in that a switch (33) is provided in the valve, which is actuated when the intermediate position is reached, and that switching means (30) are provided which, when the switch is actuated, the power supply to the valve (27) lock.
> 8. Solenoid valve according to one of claims 4 to 7, characterized in that a pressure sensor (34) and a member (35) for differentiating the voltage corresponding to the pressure are provided, and that switching means (36) are provided ι <> are that when a non-zero signal occurs at the output of the differentiating element trigger a warning signal if there is a control signal for the intermediate position. 9. Solenoid valve according to one of the speeches 4 ι »to 7, characterized in that a pressure sensor (39), an electronic memory (38) connected to it and a comparison element (40) are provided are that the control signal for the intermediate valve position the memory (38) to store tion of the voltage corresponding to the currently regulated brake pressure can be supplied. that in the comparison element a comparison between the stored voltage and the instantaneous Voltage of the pressure sensor takes place and that the j ". Comparison element (40) is designed such that at a predetermined exceeding of the stored value by the pressure sensor voltage Control signal is generated which brings the valve (27) into its second end position.