EP1222416B1 - Valve control unit for a hydraulic elevator - Google Patents

Abstract

The invention relates to a valve control device (28) for a hydraulic elevator. Said valve control device comprises two control valves (5, 15) which are used to control the flow of hydraulic oil from a lifting cylinder driving the elevator car or from the lifting cylinder to the tank. During the upward journey of the elevator car, hydraulic oil is fed from the tank to the lifting cylinder via the valve control unit (28) by means of a pump which is driven by an electric motor. During the downward journey of the elevator car, the hydraulic oil flows to the tank via the valve control unit (28) without the pump being in operation. According to the invention, a respectively individual control valve (5, 15) is provided in the valve control unit in order to control the upward and downward journeys of the elevator car, whereby each valve functions as a return valve and a proportional valve. Each control valve (5, 15) is provided with a throttle element (35; 55) which can move in relation to the seat (36; 56). A readjusting spring (37; 57) and a relay valve (5v; 15v) act upon the throttle element (35; 55) and can be actuated by an electrically controllable proportional magnet (5M; 15M). The valve control unit (28) is easily constructable and can therefore be produced at low cost. One particular advantage of the invention is that adjusting elements are not required.

Description

The invention relates to a control valve unit for a hydraulic elevator according to the preamble of claim 1.

Such control valve units are used for influencing the flow of hydraulic oil between a pump or a tank and a drive cylinder for the direct or indirect drive of an elevator car.

A control valve unit referred to in the preamble of claim 1 is known from US-A-5,040,639. It includes three pilot operated control valves and a non-return valve in which the position of the opening is monitored with a position transmitter. In addition to fixed chokes also some adjustment elements are available.

From EP-A2-0 964 163 a similar control valve unit is known, which is constructed considerably more complex and in addition to four main control valves and three pilot valves contains a whole series of mechanical adjustment elements.

From US-A-4,637,495 a control valve unit for a hydraulic elevator for controlling the upward travel is known. The valve unit has a control valve in the main flow of hydraulic fluid between the pump and the elevator cylinder and a bypass valve between supply line and return line. The control valve is designed as a spring-loaded check valve. The bypass valve is moved by a piston and hydraulically controls the opening of the control valve. The flow rate of the bypass valve can be adjusted to the operating conditions with a setting device. A control of the downward drive make further modules necessary.

US-A-4,153,074 discloses a control valve unit for controlling an elevator in which there is a pilot-operated control valve each for controlling the upward and downward travel, each acting both as a check valve and as a proportional valve. The power transmission of a respective control piston on the valve element via telescopic actuators. This arrangement is expensive to manufacture.

The invention has for its object to provide a control valve unit, which is simple and manages without adjustment. This results in lower production costs and time-consuming adjustments are not necessary during commissioning.

The stated object is achieved according to the invention by the features of claim 1. Advantageous developments emerge from the dependent claims.

Embodiments of the invention will be explained in more detail with reference to the drawing.

Fig. 1

ein Schema des hydraulischen Aufzugs samt der Einrichtung zu dessen Steuerung,

Fig. 2

eine Steuerventileinheit in einer schematischen Darstellung,

Fig. 3

die gleiche Steuerventileinheit bei Ansteuerung für die Aufwärtsfahrt des hydraulischen Aufzugs,

Fig. 4

wie Fig. 3, jedoch bei Ansteuerung für Abwärtsfahrt,

Fig. 5

einen Drosselkörper mit Gegenkolben und Stellstange,

Fig. 6

eine Ausführungsvariante für den Gegenkolben,

Fig. 7

ein Detail des Gegenkolbens,

Fig. 8a bis 8d

Varianten des Drosselkörpers,

Fig. 9a und 9b

Varianten einer Hubbegrenzung,

Fig. 10

ein Detail eines Kolbens,

Fig. 11

eine Mantelfläche des Drosselkörpers,

Fig. 12a und 12b

Teilschnitte durch einen Drosselkörper und

Fig. 13

eine spezielle Gestaltung einer Öffnung am Drosselkörper.

Show it:

Fig. 1

a diagram of the hydraulic elevator together with the device for its control,

Fig. 2

a control valve unit in a schematic representation,

Fig. 3

the same control valve unit in driving for the upward movement of the hydraulic elevator,

Fig. 4

as in FIG. 3, but when driving for downward travel,

Fig. 5

a throttle body with opposing piston and control rod,

Fig. 6

a variant for the opposite piston,

Fig. 7

a detail of the counter-piston,

Fig. 8a to 8d

Variants of the throttle body,

Fig. 9a and 9b

Variants of a stroke limitation,

Fig. 10

a detail of a piston,

Fig. 11

a lateral surface of the throttle body,

Fig. 12a and 12b

Partial sections through a throttle body and

Fig. 13

a special design of an opening on the throttle body.

In FIG. 1, 1 denotes an elevator car of a hydraulic elevator which can be moved by a reciprocating piston 2. The reciprocating piston 2 forms a known hydraulic drive together with a lifting cylinder 3. To this hydraulic drive, a cylinder line 4 is connected through which hydraulic oil can be conveyed. The cylinder line 4, on the other hand, is connected to a first control valve 5, which combines at least the functions of a proportional valve and a check valve, so that it behaves either as a proportional valve or as a check valve, which depends on how the control valve 5 is actuated, which will be discussed. The proportional valve function can be achieved in a known manner with a main valve and a pilot valve, wherein the pilot valve is actuated by an electric drive, for example a proportional solenoid. The closed check valve keeps the elevator car 1 in the respective position.

The control valve 5 is connected via a pump line 8, in which a pressure pulsation damper 9 can be arranged, with a pump 10, by means of the hydraulic oil from a tank 11 to the hydraulic drive can be conveyed. The pump 10 is driven by an electric motor 12, which is associated with a power supply part 13. In the pump line 8 there is a pressure P _P.

Between the control valve 5 and the tank 11 there is a further hydraulic oil-carrying line, namely a return line 14, in which a second control valve 15 is arranged. This control valve 15 allows the almost resistance return of the hydraulic oil from the pump 10 into the tank 11 when the pressure P _P has exceeded a certain threshold. As a result, the pressure P _P can not significantly exceed the said threshold value. It is now the case that this threshold value can be changed by an electrical signal, so that the control valve 15 can assume a pressure regulating function in a manner similar to a known proportional valve. Also, to achieve this function can, as in a proportional valve, resort in a known manner to a main valve and a pilot valve, which is actuated by a proportioning magnet, which is electrically controlled.

In the cylinder line 4 is located, preferably directly at the corresponding terminal of the control valve 5 or the control valve 5 itself, a load pressure sensor 18 which is connected via a first measuring line 19 to a control unit 20. The operation of the hydraulic elevator serving controller 20 is thus able to detect which pressure P _Z prevails in the cylinder line 4. This pressure P _Z is at standstill elevator car 1, the load of the elevator car 1 again. With the help of this pressure P _Z control and regulating operations can be influenced and operating conditions can be determined. The controller 20 may also consist of several control and regulator units.

Advantageously, a temperature sensor 21, which is connected to the control unit 20 via a second measuring line 22, is arranged on the cylinder line 4, again preferably directly on the corresponding connection of the control valve 5 or on the control valve 5 itself. Because hydraulic oil has a viscosity that varies significantly with its temperature, the control and regulation of the hydraulic elevator can be significantly improved if the temperature of the hydraulic oil is included as a parameter in the control processes.

Advantageously, another pressure sensor, namely a pump pressure sensor 23, is present, which detects the pressure P _P in the pump line 8 and is advantageously arranged directly on the corresponding connection of the pump line 8 on the control valve 5. The pump pressure sensor 23 also transmits its measured value via a further measuring line 24 to the control unit 20.

From the control unit 20, a first control line 25 leads to the control valve 5. As a result, this control valve 5 from the control unit 20 is electrically controlled. In addition, a second control line 26 leads to the control valve 15, so that it is controllable by the control unit 20 ago. In addition, a third control line 27 leads from the control unit 20 to the power supply part 13, whereby the motor 12 can be switched on and off, but optionally also the speed of the motor 12 and thus the flow rate of the pump 10 from the controller 20 can be influenced.

By controlling the control valves 5 and 15 from the controller 20 ago it is determined how the control valves 5 and 15 behave functionally. If the control valves 5 and 15 are not actuated by the control unit 20, both control valves 5 and 15 basically behave like a differently biasable check valve. If the control valves 5 and 15 are actuated by the control unit 20 by a control signal, they act as proportional valves.

According to the invention, the two control valves 5 and 15 are combined in a control valve unit 28, which is indicated in the figure by a dashed line comprising the two control valves 5 and 15. This has the advantage that the assembly work on the construction site of the hydraulic elevator is reduced. According to the general concept of the invention, the two control valves 5 and 15 are similar and constructed using the same parts, which has various advantages, which will be discussed.

Before discussing the nature of the invention in detail, the basic operation is first explained: When the elevator car 1 is stationary, it is essential that the control valve 5 is now closed, which, as already mentioned, is achieved by the control unit 20 not transmitting a control signal receives the signal line 25, so acts as a check valve. Also, the control valve 15 may be closed, but this is not necessarily always the case. So it is possible that even when the elevator car 1, the pump 10 is running, so hydraulic oil promotes, but that the pumped hydraulic oil via the control valve 15 flows back into the tank 11. As a rule, however, both control valves 5 and 15 do not receive any control signals from the control unit 20 at standstill, so that in both cases only the check valve function is possible.

The electrically non-controlled control valve 5 closes automatically by the action of the pressure P _Z , which generates the elevator car 1, when this pressure P _{Z is} greater than the pressure P _P. It has already been mentioned that in this state the load pressure sensor 18 indicates the load caused by the elevator car 1. In this case, the effective load of the elevator car 1 is determined and transmitted to the control unit 20. The controller 20 can thus detect whether the elevator car 1 is empty or loaded and the size of the load is thus known.

If the elevator car 1 is to move in the upward direction, the power supply part 13 is first activated by the control unit 20 via the control line 27, and thus the electric motor 12 is rotated, whereby the pump 10 starts to run and pumps hydraulic oil. As a result, the pressure P _P in the pump line 8 increases. As soon as this pressure P _P exceeds a value correlated with the bias of the check valve of the control valve 15, the check valve of the control valve 15 opens, so that the pressure P _P can not initially exceed this value. If this pressure value, which is usually the case, is lower than the pressure P _Z in the cylinder line 4, the control valve 5 remains closed and no hydraulic oil flows into the cylinder line 4. Thus, the switching on of the pump 10 does not cause any movement of the elevator car 1, because the entire amount of hydraulic oil delivered by the pump 10 is in this case fed back into the tank 11 via the control valve 15. In order to achieve a movement of the elevator car 1, the control unit 20 can now control the proportional valve function of the control valve 15 via the signal line 26, so that a greater hydraulic resistance is set on the control valve 15. This allows now to increase the pressure P _P until the necessary amount of hydraulic oil can flow into the cylinder line 4 through the control valve 5. In this case, part of the flow of hydraulic oil conveyed by the pump 10 flows back into the tank 11 via the control valve 15. That part of the pumped by the pump 10 stream of hydraulic oil, which is not returned via the control valve 15 in the tank 11, flows through the check valve acting as a control valve 5 due to the prevailing pressure difference via the control valve 5 in the cylinder line 4, so lifts the elevator car 1 on. In this way, continuous control of the hydraulic oil flowing to the lifting cylinder 3 is possible without the speed of the pump 10 having to be regulated. The pump 10 need only be designed so that it can supply a sufficient for the maximum speed of the elevator car 1 flow of hydraulic oil at the maximum expected back pressure at the rated speed, taking into account the usual reserve factors and other margins.

A first embodiment of the control valve unit 28 according to the invention is shown in FIGS. 2 to 4. FIG. 2 shows a basic state without any activation of the control valves 5 and 15 contained in the control valve unit 28. FIG. 3 shows a state during the upward travel of the elevator car 1 (FIG. 1), while FIG. 4 shows the state during the downward travel.

FIGS. 2 to 4 show the control valve unit 28, which represents a combination of the control valves 5 and 15. In the figures, the upper part represents the control valve 5, the lower part the control valve 15. [4] shows the connection of the control valve unit 28 to the cylinder line 4 (FIG. 1), [8] the connection to the pump line 8 and [14] the connection to the return line 14. In the terminal compartments, the prevailing pressures P _Z and P _{P are} drawn there, which have been mentioned in the description above and which can be detected with the pressure sensors not shown here. Each of the control valves 5 and 15 consists of a main valve and a pilot valve, which in turn is each actuated by a proportional solenoid.

The control valve unit 28 consists of two housing parts, namely a first housing part 30, which includes the main valves of the control valves 5 and 15, and a second housing part 31, in which the associated pilot valves are located, which are designated 5 _V and 15 _V. In this case, the housing part 31 itself may be in two parts, by each of the pilot valves 5 _V and 15 _{V has} its own housing part. Each of the pilot valves 5 _V and 15 _V is assigned a proportional solenoid, namely the pilot valve 5 _V, the proportional solenoid 5 _M and the pilot valve 15 _V, the proportional solenoid 15 _M. These proportional solenoids 5 _M and 15 _M can be actuated by the control unit 20 (FIG. 1) via the control lines 25 and 26, respectively.

The first housing part 30 contains a plurality of chambers. A first chamber is referred to as a cylinder chamber 32. This is followed by the cylinder line 4 (FIG. 1), which is why the corresponding connection is designated [4]. A second chamber is referred to as a pump chamber 33 to which the pump line 8 connects, which is represented by the reference numeral [8]. Another chamber is referred to as return chamber 34, to which the return line 14 connects, which is designated by the reference numeral [14].

In an opening between the cylinder chamber 32 and the pump chamber 33, a first throttle body 35 is arranged, which forms the main valve of the control valve 5 together with a first valve seat 36 formed in the housing part 30. According to the invention, this main valve of the control valve 5 is the essential element which directly influences the flow of hydraulic oil from and to the lifting cylinder 3 (Figure 1). For the sake of completeness, it should be mentioned that depending on the activation of the pilot valve 5 _v, a small partial flow can also flow via this pilot valve 5 _V. The main valve of the control valve 5 includes the function of a check valve and at the same time the function of a proportional valve, which will be explained below. The check valve fulfills the requirements set out in EN safety standards, so that an additional safety valve is not required.

The throttle body 35 is on the one hand actuated by a return spring 37. By this return spring 37, the main valve is kept closed as long as the pressure P _P in the pump chamber 33 is not greater than the pressure P _Z in the cylinder chamber 32. This is the case, for example the pump 10 (Figure 1) is not running and the elevator car 1 (Figure 1) is stationary.

On the throttle body 35, on the other hand, actuators act, which are moved by the control of the pilot valve 5 _V. These adjusting elements comprise an opposed piston 38 with an actuating rod 39 fastened thereto. The counter-piston 38 is displaceable in a guide space 40, which is arranged in the housing part 30. The counter-piston 38 in turn is actuated by the pilot valve 5 _V and that as follows. From the proportional solenoid 5 _M is acted in a known manner via a plunger plunger 41 against a pilot control spring 42 to a pilot piston 43. From the movement of the pilot piston 43 follows the structure of a control pressure P _X in a control pressure chamber 44. This control pressure P _X depends on the movement of the pilot piston 43 and is thus determined by the pilot control spring 42. Characterized in that the pilot valve 5 _V detects the pressure P _Z in the cylinder chamber 32 via a first connecting channel 45 and also detects the pressure prevailing in the return chamber 34 via a second connecting channel 46, no adjusting elements are required to the correct control pressure P _X to reach.

The pilot valve 5 _V controls the control pressure P _X , wherein the control pressure P _{X is} a function of the pressures in cylinder chamber 32 and return chamber 34 and the stroke of the pilot piston 43, which in turn is determined by the control of the pilot valve 5 _V.

By the control pressure P _X is acted on a displaceable in a control chamber 47 piston 48. The piston 48 is supported via a main valve control spring 49 against the housing part 30. The movement of the piston 48 is transmitted by means of a control rod 50 to the counter-piston 38. The main valve control spring 49 thus acts on the one hand as a return spring for the piston 48, on the other hand just as a control spring for the main valve of the control valve 5. Again, according to the invention no adjustment is required.

Thus, according to the invention, only a single throttle body 35, which together with the valve seat 36 influences the flow of hydraulic oil to and from the lift cylinder 3 (Figure 1), is required to perform both the function of the check valve and the function of the proportional valve to reach.

After the same basic principle, the second control valve 15 is designed. In an opening between the pump chamber 33 and return chamber 34, a second throttle body 55 is arranged, which forms the main valve of the control valve 15 together with a second valve seat 56 formed in the housing part 30. This main valve of the control valve 15 also includes the function of a check valve and at the same time the function of a proportional valve, which will be explained below.

The throttle body 55 is on the one hand actuated by a return spring 57. By this return spring 57, the main valve is kept closed as long as the pressure P _P in the pump chamber 33 is not greater than the pressure in the return chamber 34. This is the case, for example, when the pump 10 (Figure 1) is not running.

On the throttle body 55, on the other hand, actuators act, which are moved by the control of the pilot valve 15 _V. In contrast to the previously described control valve 5 15 _{M is} acted on the throttle body 55 from the proportional solenoid 15 _M without the interposition of an opposing piston at the control valve. Also, the throttle body 55 is actuated by the pilot valve 15 _V , namely as follows. From the proportional solenoid 15 _M is acted in a known manner via a plunger tang 61 against a pilot control spring 62 to a pilot piston 63. From the movement of the pilot piston 63 follows the structure of a control pressure P _Y in a control pressure chamber 64. This control pressure P _Y depends on the movement of the pilot piston 63 and is thus determined by the pilot control spring 62. Characterized in that the pilot valve 15 _V detected by a further connecting channel 65, the pressure P _P in the pump chamber 33 and detected via the aforementioned connection channel 46 and the pressure prevailing in the return chamber 34, no adjusting elements are required to the correct control pressure P _Y to reach. The connecting channel 65 is shown in dashed lines, because it lies in another plane so that it can make the connection from the pilot valve 15 _V to the pump chamber 33, bypassing the return chamber 34.

The pilot valve 15 _V controls the control pressure P _Y , the control pressure P _{Y is} a function of the pressures in the pump chamber 33 and return chamber 34 and the stroke of the pilot piston 63, which in turn is determined by the control of the pilot valve 15 _V. By the control pressure P _Y is acted on a displaceable in a control chamber 67 piston 68. The piston 68 is supported via a main valve control spring 69 against the housing part 30. The movement of the piston 68 is transmitted to the throttle body 55 by means of a control rod 70. The main valve control spring 69 thus acts on the one hand as a return spring for the piston 68, on the other hand just as a control spring for the main valve of the control valve 15. Again, no adjustment elements are required according to the invention.

This is easier to understand this with reference to FIG 3. Here, namely, a state is shown, in which the pump 10 is running, because of the increased pressure P _P, the throttle body 55 is pressed against the return spring 57 and so lifted from the valve seat 56. The proportional solenoid 15 _M is driven, whereby the piston 68 due to the increased control pressure P _Y to the left, that is shifted in the direction of the throttle body 55. The movement of the piston 68 is transmitted by the control rod 70 directly to the throttle body 55.

As soon as the pump 10 starts to run, the pressure P _P rises. But this immediately opens the main valve of the control valve 15 by the throttle body 55 moves against the return spring 57. The pumped by the pump 10 hydraulic oil flows from the pump chamber 33 in the return chamber 34 and from there via the return line 14 (Fig. 1) to the tank 11. Mention should be added that the throttle body 35 of the control valve 5 are not moved against the return spring 37 can, because due to the relatively high pressure P _Z generated by the load of the elevator car 1, the main valve of the first control valve 5 remains closed because of the positive pressure difference P _Z - P _P in any case.

In order to initiate the upward movement for the elevator car 1, as mentioned above, the proportional valve function of the control valve 15 is activated. This is done by driving the proportional solenoid 15 _M via the control line 26.

In the figure 3 is further shown that due to the increased pressure P _P , and the throttle body 35 of the main valve of the first control valve 5 has been moved against the return spring 37. This movement can then occur as soon as the pressure P _{P is} so much greater than the pressure P _Z , that the force of the return spring 37 is overcome. In the state shown in Figure 3 so hydraulic oil is conveyed through the cylinder line 4 in the lifting cylinder 3, which causes the upward movement of the elevator car 1. It should be emphasized that the opening of the main valve of the control valve 5 without the activation of the proportional solenoid 5 _M , ie without the involvement of the pilot valve 5 _V alone due to the positive pressure difference P _P -P _Z comes about. The upward movement of the elevator car 1 is thus achieved only by driving the proportional solenoid 15 _M and the main valve of the control valve 5 has only the check valve function.

Analogous to the control valve 5, the control valve 15 has a counter-body 58 and an actuating rod 59. In contrast to the control valve 5, in which the adjusting rod 39 is fixedly mounted on the counter-piston 38, while the throttle body 35 is a separate part form the control valve 15 counter-body 58, control rod 59 and throttle body 55 a single part. These differences can be clearly seen in FIGS. 2 and 3. The counter body 58 is then, when the control valve 15 is closed, in a recess 60 in the first housing part 30. The diameter of the recess 60 may be significantly larger than the diameter of the counter body 58. If this is the case, the counter body 58 has regard Force effect has no effect on the formed from the throttle body 55 and the valve seat 56 main valve of the control valve 15. Advantageously 60 guide ribs can be arranged in the recess, with which the counter body 58 is guided.

Functionally, the mating bodies 38 and 58 have the following different meanings. On the counter-body 38 and 58, the pressure in the pump chamber 33 acts in the same manner as on the throttle body 35 and 55. If now advantageously the diameter of the counter-body 38 and 58 are equal to the diameter of the throttle body 35 and 55, this causes a force balance. In the first control valve 5, in which the throttle body 35 on the one hand and counter body 38 with control rod 39 on the other hand are separate parts acts on the counter body 38, the same caused by the pressure P _P force as on the throttle body 35. The force applied by the pilot valve 5 _M. must to move the piston 48 and the control rod 50 against the opposed piston 38 and the throttle body 35, so is not changed by differential forces. When the control valve 15, the rigid connection of the counter-piston 58 with the throttle body 55 is necessary because here the counter-piston 58 is on the pilot valve 15 _M side facing away from the main valve, so that the power is not transmitted via the opposed piston 58. Because the diameter of the recess 60 is significantly larger than the diameter of the counter-piston 58, the pressure P _P acts on all sides in the case of the counter-piston 58, ie it does not develop any counterforce on the throttle body 55.

FIG. 4 shows a position of the control valve unit 28 when the pull-out booth 1 is moved downwards (FIG. 1). The pump 10 (Figure 1) will not run. Accordingly, the pressure P _{P is} small. Before the downward movement of the elevator car 1 is due to the fact that the pressure P _Z in the cylinder chamber 32 is significantly greater than the pressure P _P in the pump chamber 33, the main valve of the control valve 5 formed from throttle body 35 and seat 36 is closed. To initiate the downward movement of the elevator car 1, the proportional solenoid 5 _M activated. This acts on the plunger rod 41 on the pilot valve 5 _V , which builds up the control pressure P _X in the control chamber 47. The magnitude of the control pressure P _X is determined by the control of the proportional solenoid 5 _M and the pilot control spring 42 and is of course also influenced by the pressure P _Z in the cylinder chamber 32 and the pressure in the return chamber 34. With increasing activation of the proportional solenoid 5 _M , the control pressure P _X in the control pressure chamber 44 increases, as a result of which the piston 48 is moved against the force of the main valve control spring 49 in the direction of the counter-piston 38. In this case, this movement is transmitted via the control rod 50 to the counter-piston 38. Whose movement is transmitted via the control rod 39 to the throttle body 35. Thus, the main valve of the control valve 5 opens.

As a result of this opening, the pressure P _P in the pump chamber 33 increases. As a result, the throttle body 55 is pressed against the restoring spring 57, so that the throttle body 55 lifts off from the valve seat 56. The hydraulic oil can now flow via the main valve of the control valve 15 formed by the throttle body 55 and the valve seat 56 via the return chamber 34 into the return line 14 (FIG. 1) and thus into the tank 11. It should be mentioned for the sake of completeness that a part of the hydraulic oil can also flow back from the pump chamber 33 via the pump line 8 (FIG. 1) and the pump 10 into the tank 11, because the pumps usually indicate a leakage. Which partial flow flows through the pump 10 depends on the design of the pump 10 and the spring rate of the return spring 57. It is quite possible, depending on the design of the pump 10, that the pump 10, although not driven by the motor 12, is rotated by the flow of hydraulic oil. For the sake of completeness, it should also be mentioned that a further partial flow also flows via the pilot valve 5 _V.

The main valve of the control valve 15 formed from throttle body 55 and valve seat 56 thus acts as a check valve when traveling downwards, which valve is opened solely by the pressure P _P. A control of the proportional solenoid 15 _M thus does not take place and thus the pilot valve 15 _V without function.

To control the upward and downward travel of the elevator car 1 (FIG. 1), therefore, according to the invention, only the two control valves 5 and 15 are required, each having the functions of non-return valve and proportional valve. The check valve functions of the control valves 5 and 15 simultaneously meet the requirements of EN safety standards. In this case, the control valve 5 fulfills the function of the safety valve, while the control valve 15 makes an additional pump pressure relief valve dispensable. The inventive control valve unit 28 thus has a particularly simple structure and is inexpensive to produce. If the throttle body 35 and 55 are identical according to an advantageous embodiment of the invention, this also means an advantage in terms of manufacturing costs, because not different throttle body must be fabricated.

It is advantageous if the counter-bodies 38 and 58 have no flat surface on their side facing the throttle body 35 or 55, but rather if the side facing the throttle body 35 or 55 has the shape of a truncated cone. FIG. 5 shows the closing body 55 together with the counterbody 58 and the actuating rod 59 connecting these two parts. The surface facing the truncated cone 55 has the shape of a truncated cone 80. Advantageously, the surface of the truncated cone 80 forms an angle a of approximately 15 to 25 degrees against a surface perpendicular to the longitudinal axis. This ensures that at high flow rate through the main valve of the control valve 15 resulting dynamic forces have no adverse effects on the pilot valve 15 _V.

It is also advantageous if the counter body 58 of the control valve 15 has the same shape and size as the counter body 38 of the control valve 5. If the counter-body 38 and 58 are identical, this has the advantage that less different parts must be manufactured and kept and The batch size is twice as large, which has a favorable effect on production costs. This is also important with regard to service work on site. FIG. 6 shows a counterbody 58 whose shape and size correspond to the counterbody 38 (FIG. 4). The angle a is also present here. In the figure 7, the counter-body is again shown, which is usable as a counter-body 38 for the control valve 5 and as a counter-body 58 for the control valve 15, in turn, the angle á occurs.

The size of the recess 60 is in each case adapted to the size of the counter body 58. Thus, if the counter-body 58 is designed according to FIG. 5, the depth of the recess 60 is small. However, if the size of the counter body 58 is designed in accordance with FIG. 6, then the depth of the recess 60 is correspondingly greater, so that the counter body 58 fits into the recess 60 when the main valve of the second control valve 15 is closed.

Details of the throttle body 35, 55 are shown in FIGS. 8a to 8d, namely different variants of the embodiment. To a base 90 is followed in each case a cylinder 91, whose lateral surface is designated by the reference numeral 92. In the cylinder 91 openings 93 are milled through which the hydraulic oil can pass. Advantageously, for example, six uniformly distributed openings 93 are milled into the circumference of the cylinder 91. The openings 93 may have different shapes. In the embodiment according to FIG. 8 a, the openings 93 in the part adjoining the base 90 are V-shaped and in the adjoining part of constant width. It follows that the effective flow cross-section for the hydraulic oil with increasing stroke of the throttle body 35, 55 initially increases linearly and then with further increasing stroke. In the embodiment of Figure 8b, the openings 92 in the adjoining the base part instead of the V-shaped a cup-shaped. It follows that the effective flow area for the hydraulic oil is non-linear. Starting from the closed state of the control valves 5 and 15 increases when actuated in the opening direction of the effective flow cross section for the hydraulic oil initially only a little, then becomes increasingly larger with increasing stroke and then later with increasing increasing stroke decreasing larger. Afterwards it stays constant again.

In the figure 8c an example is shown in which the openings 93 are clearly stepped. In the first stroke region, the opening 93 is V-shaped and then abruptly changes into a rectangular shape. This means that the effective passage cross section for the hydraulic oil initially increases slightly and then changes abruptly to a maximum value, in which case the passage cross section is independent of the further stroke.

FIG. 8d shows a further example in which the openings 93 are only stepped. In the first stroke range, the opening 93 has a small width and then goes abruptly into one

Rectangular shape larger width over. This means that the effective flow cross-section for the hydraulic oil initially has a first value and then changes abruptly to a maximum value, in which case the passage cross-section is independent of the further stroke.
Due to the shape of the throttle body 35, 55, therefore, the flow characteristics of the control valves 5 and 15 can be adapted to the respective elevator installation and to the type of control within wide limits. The examples shown above give an idea of the possibilities that arise. By different shapes of the throttle body 35 and 55, the control valves 5 and 15 can therefore be adapted to different tasks and systems. In the known state of the art, different designs and sizes exist for the different applications. By the invention is thus achieved that with only a single control valve unit 28 by minor modifications both smaller and larger elevator systems are controllable.

A further advantageous embodiment is to provide a stroke limitation. Such a stroke limitation can advantageously be achieved by limiting the possible travel of the pistons 48 and 68 within the control chamber 47 and 67, respectively. Suitable variants are shown in FIGS. 9a and 9b.

FIG. 9a shows a detail from FIGS. 2 to 4, namely the control chamber 47 or 67 with the piston 48 or 68 displaceable in it. Numerous annular grooves 95 are inserted into the cylindrical inner wall of the control chamber 47 or 67. In this annular grooves 95 snap rings 96 can be used. Depending on the desired stroke limitation, a snap ring 96 is inserted into one of the annular grooves 95. Thus, the stroke that can make the piston 48 and 68, limited. Exactly according to the stroke of the throttle body 35 and 55 of the control valves 5 and 15 (Fig. 2 to 4) is limited. In this way it is possible, when mounting the control valve unit 28, to determine for which maximum nominal flow the control valve unit 28 should be designed. Different sizes of control valve units 28 are thus unnecessary.

An advantageous variant of the stroke limitation is shown in FIG. 9b. Here, the production-technically problematic annular grooves 95 (FIG. 9a) are not necessary. Instead, a spacer ring 97 is inserted into the control chamber 47 and 67, respectively. Its outer diameter is slightly smaller than the diameter of the control chamber 47 and 67, respectively. Here, the length of the cylindrical spacer determines the stroke limit. Compared to the variant of Figure 9a, in which the possible stroke limitations, namely, for example, 5, 8, 11 and 14 mm, depend on the positions of the individual annular grooves 95, there is the possibility to provide any stroke limitations.

FIG. 10 shows a detail of the pistons 48, 68. They have on their outer periphery a groove 98 in which an annular elastic seal 99 is inserted. By this seal 99, the gap between the cylindrical outer surface of the piston 48, 68 and the inner wall of the control chamber 47, 67 (Fig. 2) is largely filled. The seal 99 advantageously fulfills the task of reducing the leakage, because by it the leakage flow of hydraulic oil from the control chamber 47, 67 in the direction of the main valve of the control valves 5, 15 is decisively reduced.

FIG. 11 shows the lateral surface of a throttle body 35 (FIG. 2). The openings 93 already mentioned in connection with FIGS. 8a to 8d, which have different shapes there, but each have the same size on a throttle body 35, are not all of the same size here. The opening 93 of Figure 11 begins at a distance d from the base 90 (Figure 8a-d), while another opening 93 'begins at a distance d' and another opening 93 "at a distance d". The smallest distance d is, for example, 1 mm. By this different size of the individual openings 93 is advantageously achieved that on the determination of the individual distances d, d ', d ", etc., the valve-dependent flow characteristic is arbitrarily fixed, so as to make the flow characteristics optimally adaptable to the needs. ,

Further possible details of openings 93 are shown in FIGS. 12a and 12b. In FIG. 12 a, an opening 93 is shown, the root 93 w of which, analogous to FIG. 11, begins at a specific distance from the base 90. The depth of such opening, as well as the width, advantageously follows a design rule characterized in that the effective area A of the opening 93 is a function of a distance y from the root 93w. A particularly advantageous dimensioning rule is that the area A is proportional to the 2.5th power of the distance y, that is to say the following formula: $$\mathrm{A}=\mathrm{k}\cdot {\mathrm{y}}^{2.5}$$

In this formula, k is a proportionality factor.

FIG. 12b shows a section to FIG. 12a at a distance y from the root 93w. In contrast to the exemplary embodiment of FIG. 11, all openings 93 begin with their root 93w (FIG. 12a) at the same distance from the base 90, but it is also conceivable that this solution would be co-ordinated with that of FIG 12b is indicated by the fact that one of the openings is deeper with a dashed line, because its root 93w begins at a smaller distance from the base 90.

FIG. 13 shows a boundary line of an opening 93 in a particularly advantageous form. In the region of the root of the opening 93, this opening 93 has a radius of, for example, 1 mm. A 180-degree arch is followed by curved boundary lines. The design of these boundary lines can achieve special flow characteristics.

Basically, the above-described special measures of the design of the openings 93 serve the purpose of achieving that a sufficiently large pressure control range is available at all flow rates.

The inventive control valve unit 28 has initially been described in connection with FIG. The pressure sensors 18 and 23 required in this type of control were not shown in the further figures because the prior art already provides examples for this. The same applies to the temperature sensor.

However, the control valve unit 28 according to the invention is not only intended to be used in connection with a system shown in FIG. 1 in the mode of operation mentioned according to the description of FIG. Thus, the inventive control valve unit 28 can also be used in any other design variants, for example even if the pump 10 is speed-controlled, which also entails another control principle for the control valve unit 28.

Claims (16)

1. Control valve unit (28) for a hydraulic lift, which valve unit contains control valves (5, 15) and pilot valves (5_V, 15_V) with which it is possible to control the flow of hydraulic oil from a tank (11) to a lifting cylinder (3) driving a lift cabin (1), and from the lifting cylinder (3) to the tank (11), it being possible, for an ascent of the lift cabin (1), for the hydraulic oil to be conveyed by means of a pump (10) driven by an electrical motor (12) from the tank (11) by way of the control valve unit (28) to the lifting cylinder (3) and, for a descent of the lift cabin (1), for the hydraulic oil to be conveyed by way of the control valve unit (28) to the tank (11), and a respective single pre-controllable control valve (5, 15), each of which acts both as a non-return valve and as a proportional valve, being present for controlling the ascent and the descent of the lift cabin (1), characterised in that,
   in the case of the control valve (5) that controls descent, power transmission is effected from its pilot valve (5_V) by means of a piston (48), acting against a main valve governing spring (49), and by way of a control rod (50) onto an opposed piston (38) which, by means of an adjusting rod (39) secured thereto, moves a throttle body (35), the diameter of the opposed piston (38) being the same as the diameter of the throttle body (35), and,
   in the case of the control valve (15) that controls ascent, power transmission is effected from its pilot valve (15_V) by means of a piston (68), acting against a main valve governing spring (69), and by way of a control rod (70) onto a throttle body (55), and in that the throttle body (55) is connected securely to an opposed piston (58) by way of an adjusting rod (59), the diameter of the opposed piston (58) being the same as the diameter of the throttle body (55).
2. Control valve unit (28) according to claim 1, characterised in that a single throttle body (35; 55) which is displaceable relative to a seat (36; 56) is present in each of the control valves (5, 15).
3. Control valve unit (28) according to claim 2, characterised in that, on the one hand, a return spring (37; 57) and, on the other hand, a pilot valve (5_V; 15_V) act on the throttle body (35; 55) and each of them can be operated by an electrically actuable proportional magnet (5_M; 15_M).
4. Control valve unit (28) according to claim 3, characterised in that, in the case of the control valve (15) that controls ascent, its return spring (57) and its pilot valve (15_V) act in the same direction on its throttle body (55) in the closing direction.
5. Control valve unit (28) according to claim 3, characterised in that, in the case of the control valve (5) that controls descent, its return spring (37) acts on its throttle body (35) in the closing direction while its pilot valve (5_V) acts in the opening direction.
6. Control valve unit (28) according to claims 4 and 5, characterised in that the throttle body (35) of the control valve (5) controlling descent and the throttle body (55) of the control valve (15) controlling ascent have the same form and dimensions.
7. Control valve unit (28) according to claim 1, characterised in that the piston (48; 68) has, on its outer circumference, a groove (98) into which a resilient seal (99) is inserted.
8. Control valve unit (28) according to claim 1, characterised in that the face of the opposed body (38; 58) facing the throttle body (35; 55) is in the form of a truncated cone.
9. Control valve unit (28) according to claim 8, characterised in that the outer surface of the truncated cone (80) forms an angle a of approximately from 15 to 25 degrees relative to a face standing perpendicularly on the longitudinal axis.
10. Control valve unit (28) according to any one of claims 1 to 9, characterised in that the throttle bodies (35; 55) are formed from a base (90) and an adjoining cylinder (91) in whose outer surface (92) openings (93) are milled.
11. Control valve unit (28) according to claim 10, characterised in that the openings (93) are at least partially V-shaped.
12. Control valve unit (28) according to claim 10, characterised in that the openings (93) are goblet-shaped.
13. Control valve unit (28) according to claim 10, characterised in that the openings (93) are stepped.
14. Control valve unit (28) according to any one of claims 1 to 13, characterised in that means (95, 96; 97) are present by which the path of the piston (48; 68) can be delimited.
15. Control valve unit (28) according to claim 14, characterised in that the path is delimited by a snap ring (96) which can be inserted into one of several annular grooves (95) cut into the cylindrical inner wall of control chambers (47; 67).
16. Control valve unit (28) according to claim 14, characterised in that a cylindrical spacer ring (97) can be inserted into the control chamber (47; 67), the outside diameter of which ring is slightly smaller than the diameter of the control chamber (47; 67) and by means of the length of which the limit of lift can be determined.

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