EP1222416A2

EP1222416A2 - Valve control unit for a hydraulic elevator

Info

Publication number: EP1222416A2
Application number: EP01962699A
Authority: EP
Inventors: Sead Veletovac; Luigi Del Re; Andreas Schrempf
Original assignee: Wittur AG
Current assignee: Wittur AG
Priority date: 2000-07-03
Filing date: 2001-06-01
Publication date: 2002-07-17
Anticipated expiration: 2021-06-01
Also published as: CA2383190A1; EP1222416B1; WO2002002974A3; US6742629B2; US20020153204A1; PL357194A1; BR0106900A; AU8383101A; WO2002002974A2; JP2004502114A; KR20020030792A; AU770145B2; MXPA01013142A; DE50111267D1; HRP20020191A2

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

Control valve unit for a hydraulic elevator

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 to influence 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 of the type mentioned in the preamble of claim 1 is known from US-A-5,040,639. It includes three pilot operated control valves and a check valve, in which the position of the opening is monitored with a position transmitter. In addition to fixed throttles, there are also some adjustment elements.

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

The invention has for its object to provide a control valve unit which is simple in construction and does not require any adjustment elements. This results in lower manufacturing costs and time-consuming settings are not necessary during commissioning.

According to the invention, the stated object is achieved by the features of claim 1. Advantageous further developments result from the dependent claims. Exemplary embodiments of the invention are explained in more detail below with reference to the drawing.

1 shows a diagram of the hydraulic elevator including the device for controlling it,

2 shows a control valve unit in a schematic representation,

3 shows the same control valve unit when actuated for the upward movement of the hydraulic elevator,

4 like FIG. 3, but with activation for downward travel,

5 shows a throttle body with counter-piston and adjusting rod,

6 shows an embodiment variant for the counter-piston,

7 shows a detail of the opposing piston,

8a to 8d variants of the throttle body,

9a and 9b variants of a stroke limitation,

10 shows a detail of a piston,

11 is a lateral surface of the throttle body,

12a and 12b partial sections through a throttle body and

Fig. 13 shows a special design of an opening on the throttle body. In FIG. 1, 1 means an elevator car of a hydraulic elevator, which can be moved by a reciprocating piston 2. The reciprocating piston 2 forms, together with a lifting cylinder 3, a known hydraulic drive. A cylinder line 4 is connected to this hydraulic drive, through which hydraulic coils 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 like a proportional valve or like a check valve, which depends on how the control valve 5 is controlled, what is still discussed. The proportional valve function can be achieved in a known manner with a main valve and a pilot valve, the pilot valve being actuated by an electric drive, for example a proportional magnet. The closed check valve holds the elevator car 1 in the respective position.

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

Between the control valve 5 and the tank 11 there is a further line leading to hydraulic piston, namely a return line 14, in which a second control valve 15 is arranged. This control valve 15 allows the hydraulic oil to flow back almost without resistance from the pump 10 into the tank 11 when the pressure P _P has exceeded a certain threshold value. As a result, the pressure P _P cannot substantially exceed 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 take over a pressure control function in a manner similar to a known proportional valve. To achieve this function, as in the case of a proportional valve, a main valve and a pilot valve can be used in a known manner, which is actuated by a proportional magnet which can be controlled electrically. A load pressure sensor 18 is located in the cylinder line 4, preferably directly at the corresponding connection of the control valve 5 or on the control valve 5 itself, and is connected to a control unit 20 via a first measuring line 19. The control device 20 serving to operate the hydraulic elevator is thus able to recognize the pressure P _z prevailing in the cylinder line 4. When the elevator car 1 is at a standstill, this pressure P _z reflects the load on the elevator car 1. With the help of this pressure P _z , control and regulating processes can be influenced and operating states can be determined. The control unit 20 can also consist of several control and regulator units.

A temperature sensor 21, which is connected to the control unit 20 via a second measuring line 22, is advantageously arranged on the cylinder line 4, again preferably directly at the corresponding connection of the control valve 5 or on the control valve 5 itself. Because hydrauhkol 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 control and regulating processes.

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

A first control line 25 leads from the control unit 20 to the control valve 5. As a result, this control valve 5 can be electrically controlled from the control unit 20. In addition, a second control line 26 leads to the control valve 15, so that this can also be controlled by the control unit 20. 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 possibly also the speed of the motor 12 and thus the delivery rate of the pump 10 can be influenced by the control unit 20. By controlling the control valves 5 and 15 from the control unit 20, 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 check valve that can be preloaded differently. If the control valves 5 and 15 are actuated by the control device 20 by means of 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 effort on the construction site of the hydraulic elevator is reduced. According to the general idea of the invention, the two control valves 5 and 15 are similar and constructed using the same parts, which has different advantages, which will be discussed below.

Before going into the essence of the invention in detail, the principle of operation should be explained first: When the elevator car 1 is at a standstill, it is essential that the control valve 5 is now closed, which, as already mentioned, is achieved by the control unit 20 not having a control signal receives the signal line 25, that is, acts as a check valve. The control valve 15 can also be closed, but this is not always the case. It is thus possible for the pump 10 to run, ie for delivering hydraulic oil, even when the elevator car 1 is at a standstill, but for the hydraulic oil being pumped to flow back into the tank 11 via the control valve 15. As a rule, however, both control valves 5 and 15 do not receive any control signals from control unit 20 when they are at a standstill, so that in both cases only the check valve function is possible.

The electrically not controlled control valve 5 closes automatically due to the effect of the pressure P _z which the elevator car 1 generates 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. The effective load of the elevator car 1 is determined and transmitted to the control unit 20. The control device 20 can thus recognize whether the elevator car 1 is empty or loaded and the size of the load is thus also known. If the elevator car 1 is to move in the upward direction, the control unit 20 first activates the power supply part 13 via the control line 27 and thus sets the electric motor 12 in rotation, as a result of which the pump 10 starts to run and promotes hydraulic power. As a result, the pressure P _P in the pump line 8 rises. As soon as this pressure P _P exceeds a value correlated with the pretension of the check valve of the control valve 15, the check valve of the control valve 15 opens, so that the pressure P _P cannot initially exceed this value , If this pressure value, which will usually be the case, is lower than the pressure P _z in the cylinder line 4, the control valve 5 remains closed and no hydraulic fluid flows into the cylinder line 4. Thus, switching on the pump 10 does not cause the elevator car 1 to move, because in this case the entire amount of hydraulic oil delivered by the pump 10 is returned to the tank 11 via the control valve 15. In order to achieve 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 now allows the pressure P _P to be increased until the necessary amount of hydraulic oil can flow into the cylinder line 4 through the control valve 5. 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 hydraulic fluid which is pumped by the pump 10 and which is not returned to the tank 11 via the control valve 15 flows through the control valve 5 acting as a check valve due to the prevailing pressure difference via the control valve 5 into the cylinder line 4, thus lifting the elevator car 1 on. In this way, a stepless 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 only has to be designed in such a way that it can deliver a flow rate of hydraulic oil sufficient for the maximum speed of the elevator car 1 at the maximum expected back pressure at the nominal speed, taking into account the usual reserve factors and other margins.

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

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), and [8] shows the connection to the pump line 8 and with [14] the connection to the return line 14. The pressures P _z and P _P prevailing in the connection spaces are drawn in, which were 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 actuated by a proportional magnet.

The control valve unit 28 consists of two housing parts, namely a first housing part 30, which contains the main valves of the control valves 5 and 15, and a second housing part 31, in which the associated pilot valves, which are denoted by 5 _V and 15 _V , are accommodated. The housing part 31 itself can be in two parts, in that each of the pilot valves 5 _V and 15 _{V has} its own housing part. A proportional magnet is assigned to each of the pilot valves 5 _V and 15 _v , namely the pilot valve 5 _V the proportional magnet 5 _M and the pilot valve 15 _v the proportional magnet 15 _M. These proportional magnets 5 _M and 15 _M can be controlled by control unit 20 (FIG. 1) via control lines 25 and 26, respectively.

The first housing part 30 contains several chambers. A first chamber is referred to as a cylinder chamber 32. The cylinder line 4 (FIG. 1) connects to this, which is why the corresponding connection is designated by [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 symbol [8]. Another chamber is referred to as the return chamber 34, to which the return line 14 connects, which is correspondingly designated by the reference symbol [14]. A first throttle body 35 is arranged in an opening between the cylinder chamber 32 and the pump chamber 33 and, together with a first valve seat 36 formed in the housing part 30, forms the main valve of the control valve 5. According to the invention, this main valve of the control valve 5 is the essential element which directly influences the flow of hydraulic fluid to and from the lifting cylinder 3 (FIG. 1). For the sake of completeness, it should be mentioned that, depending on the control of the pilot valve 5 _V, a small partial current can also be 5 _V via this pilot valve. The main valve of the control valve 5 contains the function of a check valve and at the same time the function of a proportional valve, which is 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 actuated on the one hand by a return spring 37. The main valve is kept closed by this return spring 37 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, when the pump 10 (FIG. 1) is not running and the elevator car 1 (FIG. 1) is at a standstill.

On the other hand, control elements act on the throttle body 35 and are moved by the control of the pilot valve 5 _V. These adjusting elements comprise a counter-piston 38 with an adjusting rod 39 fastened thereon. 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 can be actuated by the pilot valve 5 _V as follows. The proportional magnet 5 _M acts on a pilot piston 43 in a known manner via a plunger plunger 41 against a pilot control spring 42. The movement of the pilot piston 43 results in the build-up 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 therefore also determined by the pilot control spring 42. Because the pilot valve 5 _V detects the pressure P _z in the cylinder chamber 32 via a first connecting duct 45 and also detects the pressure prevailing in the return chamber 34 via a second connecting duct 46, no adjustment elements are required in order to obtain the correct control pressure Px to reach. The pilot valve 5 _V regulates the control pressure Pχ ₅ , the control pressure P _{x being} a function of the pressures in the cylinder chamber 32 and the 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.

The control pressure P acts on a piston 48 which is displaceable in a control chamber 47. The piston 48 is supported by a main valve control spring 49 against the gel part 30. The movement of the piston 48 is transmitted to the counter-piston 38 by means of a control rod 50. The main valve control spring 49 thus acts on the one hand as a return spring for the piston 48, but on the other hand also acts as a control spring for the main valve of the control valve 5. According to the invention, no adjustment elements are required here either.

According to the invention, therefore, only a single throttle body 35, which, together with the valve seat 36, influences or determines the flow of the hydraulic oil to and from the lifting cylinder 3 (FIG. 1), is required both for the function of the check valve and for the function of the proportional valve to reach.

The second control valve 15 is designed according to the same basic principle. A second throttle body 55 is arranged in an opening between the pump chamber 33 and the return chamber 34 and, together with a second valve seat 56 formed in the housing part 30, forms the main valve of the control valve 15. 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 is explained below.

The throttle body 55 is actuated on the one hand by a return spring 57. This return spring 57 keeps the main valve 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 (Fig. 1) is not running. On the other hand, control elements act on the throttle body 55 and are moved by the control of the pilot valve 15 _v . In contrast to the above-described control valve 5 is acted _M 15 without the interposition of a counter-piston to the throttle body 55 when control valve 15 by the proportional solenoid. The throttle body 55 can also be actuated by the pilot valve 15 _v as follows. The proportional magnet 15 _M acts in a known manner on a pilot piston 63 via a plunger plunger 61 against a pilot control spring 62. The movement of the pilot piston 63 results in the build-up of a control pressure Py in a control pressure chamber 64. This control pressure P _γ depends on the movement of the pilot piston 63 and is therefore also determined by the pilot control spring 62. Because the pilot valve 15 _v detects the pressure P _P in the pump chamber 33 via a further connection duct 65 and also detects the pressure prevailing in the return chamber 34 via the connection duct 46 mentioned above, no adjustment elements are required to determine the correct one To reach control pressure Py. The connecting channel 65 is shown in dashed lines because it lies in a different 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 regulates the control pressure P _γ , the control pressure P _{γ being} a function of the pressures in the pump chamber 33 and the return chamber 34 and the stroke of the pilot piston 63, which in turn is determined by the actuation of the pilot valve 15 _v . The control pressure P _{γ acts} on a piston 68 which is displaceable in a control chamber 67. The piston 68 is supported by 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, but on the other hand also as a control spring for the main valve of the control valve 15. Here too, no adjustment elements are required according to the invention.

This is more readily understood with reference to FIG 3. Here, a state is in fact illustrated in which the pump 10 is running, the throttle body 55 is pressed due to the increased pressure P _P against the return spring 57 and thus has lifted from the valve seat 56th The proportional magnet 15 _M is activated, whereby the piston 68 due to the increased control Pressure P _γ is shifted to the left, ie in the direction of the throttle body 55. The movement of the piston 68 is transmitted directly to the throttle body 55 by the control rod 70.

As soon as the pump 10 starts to run, the pressure P _{P increases} . However, the main valve of the control valve 15 is immediately opened by the throttle body 55 moving against the return spring 57. The hydraulic pump conveyed by the pump 10 flows from the pump chamber 33 into the return chamber 34 and from there via the return line 14 (FIG. 1) to the tank 11. It should also be mentioned that the throttle body 35 of the control valve 5 is not moved against the return spring 37 can, because the main valve of the first control valve 5 remains closed due to the positive pressure difference P _z - P _P due to the relatively high pressure P _z generated by the load of the elevator car 1 in any case.

In order to initiate the upward travel for the elevator car 1, the proportional valve function of the control valve 15 is activated, as mentioned at the beginning. This is done by actuating the proportional magnet 15 _M via the control line 26.

FIG. 3 also shows that, as a result of the increased pressure P _P , the throttle body 35 of the main valve of the first control valve 5 has also 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 also overcome. In the state shown in FIG. 3, hydraulic piston is thus conveyed through the cylinder line 4 into the lifting cylinder 3, which causes the elevator car 1 to move upwards. It should be emphasized that the opening of the main valve of the control valve 5 takes place without the control of the proportional magnet 5 _M , that is to say without the involvement of the pilot valve 5 _V, solely because of the positive pressure difference P _P -P _Z. The upward travel of the elevator car 1 is thus achieved solely by actuating the proportional magnet 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 also has a counter body 58 and an actuating rod 59. In contrast to the control valve 5, in which the actuating rod 39 is fixedly attached to the counter-piston 38, while the throttle body 35 is a separate part in the control valve 15 counter body 58, adjusting 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 can be significantly larger than the diameter of the counter body 58. If this is the case, the counter body 58 has regard to The effect of force has no influence on the main valve of the control valve 15 formed from the throttle body 55 and the valve seat 56. Guide ribs with which the counter body 58 is guided can advantageously be arranged in the recess 60.

Functions, the counter bodies 38 and 58 have the following different meanings. The pressure in the pump chamber 33 acts on the counter-bodies 38 and 58 in the same way as on the throttle bodies 35 and 55. If the diameters of the counter-bodies 38 and 58 are advantageously the same size as the diameters of the throttle bodies 35 and 55, this results a balance of forces. In the first control valve 5, in which the throttle body 35 on the one hand and the counter body 38 with the actuating rod 39 on the other hand are separate parts, the same force acting on the throttle body 35 as is caused by the pressure P _P acts on the throttle body 35. The force which the pilot valve 5 _M exerts must in order to move the piston 48 and the control rod 50 against the counter-piston 38 and the throttle body 35 is not changed by differential forces. With the control valve 15, the rigid connection of the counter-piston 58 to the throttle body 55 is necessary because here the counter-piston 58 lies on the side of the main valve facing away from the pilot valve 15 _M , so that the force is not transmitted via the counter-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 counter-piston 58, and therefore 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 cabin 1 (FIG. 1) moves downward. The pump 10 (FIG. 1) then does not run. Accordingly, the pressure P _{P is} small. Before the downward movement of the elevator car 1 begins, 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 the throttle body 35 and seat 36 is closed. To initiate the downward movement of the elevator car 1, the pro- portionalmagnet 5 _M driven. This acts via the plunger plunger 41 on the pilot valve 5 _V , which builds up the control pressure P _x in the control chamber 47. The size of the control pressure P _x is determined by the control of the proportional magnet 5M and the pilot control spring 42 and is of course also influenced by the pressure P _z in the cylinder chamber 32 and by the pressure in the return chamber 34. With increasing activation of the proportional magnet 5 _M , the control pressure P _x in the control pressure chamber 44 increases, as a result of which the piston 48 is moved in the direction of the counter-piston 38 against the force of the main valve control spring 49. This movement is transmitted to the counter-piston 38 via the control rod 50. Whose movement is transmitted to the throttle body 35 via the adjusting rod 39. The main valve of the control valve 5 thus opens.

This opening now increases the pressure P _P in the pump chamber 33. As a result, the throttle body 55 is pressed against the return spring 57, so that the throttle body 55 lifts off the valve seat 56. The hydraulic piston can now flow through the main valve of the control valve 15, formed from the throttle body 55 and valve seat 56, via the return chamber 34 into the return line 14 (FIG. 1) and thus into the tank 11. For the sake of completeness, it should be mentioned that 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 have a leakage loss. 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. Depending on the design of the pump 10, it is entirely possible that the flow of the hydraulic oil causes the pump 10 to rotate, although it is not driven by the motor 12. 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 the throttle body 55 and the valve seat 56 thus acts as a check valve when traveling downward, which is opened solely by the pressure P _P. The proportional solenoid 15M is therefore not actuated and therefore the pilot valve 15 _v is also without function.

To control the upward and downward movement of the elevator car 1 (FIG. 1), only the two control valves 5 and 15 are required according to the invention, each of which functions of check valve and proportional valve combine. The check valve functions of control valves 5 and 15 also meet the requirements of EN safety standards. The control valve 5 fulfills the function of the safety valve, while the control valve 15 makes an additional pump pressure relief valve unnecessary. The control valve unit 28 according to the invention thus has a particularly simple structure and can be produced inexpensively. If the throttle bodies 35 and 55 are identical according to an advantageous embodiment of the invention, this also means an advantage in terms of production costs because different throttle bodies do not have to be manufactured.

It is advantageous if the counter bodies 38 and 58 do not have a flat surface on their side facing the throttle body 35 or 55, but 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 counter body 58 and the connecting rod 59 connecting these two parts. The surface facing the closing body 55 has the shape of a truncated cone 80. The surface of the truncated cone 80 advantageously forms an angle Winkel of approximately 15 to 25 degrees with respect to a surface perpendicular to the longitudinal axis. It is thereby achieved that dynamic forces generated by the main valve of the control valve 15 at a high flow rate have no adverse repercussions 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 bodies 38 and 58 are identical, this has the advantage that fewer different parts have to be manufactured and kept in stock the production lot size is twice as large, which has a favorable effect on production costs. This is also important with regard to service work on site. A counter body 58 is shown in FIG. 6, the shape and size of which corresponds to the counter body 38 (FIG. 4). The angle a is also present here. FIG. 7 shows the counter body again, which can be used as a counter body 38 for the control valve 5 and as a counter body 58 for the control valve 15, with the angle a again occurring. The size of the recess 60 is in each case adapted to the size of the counter body 58. If the counter body 58 is designed according to FIG. 5, the depth of the recess 60 is small. If, however, the size of the counter body 58 is designed according to FIG. 6, the depth of the recess 60 is correspondingly greater, so that the counter body 58 can be accommodated in the recess 60 when the main valve of the second control valve 15 is closed.

Details of the throttle bodies 35, 55 are shown in FIGS. 8a to 8d, namely different design variants. A cylinder 91 connects to a base 90, the lateral surface of which is designated by the reference number 92. Openings 93 are milled into the cylinder 91, through which the hydraulic piston can pass. For example, six evenly distributed openings 93 are advantageously milled into the circumference of the cylinder 91. The openings 93 can have different shapes. In the exemplary embodiment according to FIG. 8a, the openings 93 in the part adjoining the base 90 are V-shaped and in the part adjoining them are of constant width. It follows from this that the effective passage cross section for the hydraulic piston initially increases progressively with increasing stroke of throttle body 35, 55 and then increases linearly with increasing stroke. In the embodiment according to FIG. 8b, the openings 92 in the part adjoining the base have a cup-shaped shape instead of the V-shaped one. This means that the effective passage cross-section for the hydraulic piston is non-linear. Starting from the closed state of the control valves 5 and 15, the effective passage cross-section for the hydraulic piston initially increases only slightly when actuated in the opening direction, then becomes increasingly larger with increasing stroke and then later decreases with increasing stroke. Then it remains constant.

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

Another example is shown in FIG. 8d, in which the openings 93 are only stepped. In the first stroke range, the opening 93 has a small width and then abruptly goes into one Rectangular shape greater width. This means that the effective passage cross-section for the hydraulic piston initially has a first value and then changes abruptly to a maximum value at which the passage cross-section is then independent of the further stroke. The shape of the throttle bodies 35, 55 means that the flow characteristics of the control valves 5 and 15 can be adapted within wide limits to the respective elevator system and the type of control. The examples shown above give an idea of the possibilities that are available. By different designs of the throttle bodies 35 and 55, the control valves 5 and 15 can thus be adapted to different tasks and systems. In the known prior art, different types and sizes exist for the different applications. It is thus achieved by the invention that both small and large elevator systems can be controlled with only a single control valve unit 28 by slight modifications.

A further advantageous embodiment consists in providing a stroke limitation. Such a stroke limitation can advantageously be achieved in that the possible path of the pistons 48 and 68 within the control chamber 47 and 67 is limited. Suitable variants are shown in FIGS. 9a and 9b.

FIG. 9 a shows a detail from FIGS. 2 to 4, namely the control chamber 47 or 67 with the piston 48 or 68 which can be displaced therein. A number of annular grooves 95 are pierced into the cylindrical inner wall of the control chamber 47 and 67. Snap rings 96 can be inserted into these ring grooves 95. Depending on the desired stroke limitation, a snap ring 96 is inserted into one of the ring grooves 95. The stroke that the piston 48 or 68 can make is thus limited. The stroke of the throttle bodies 35 and 55 of the control valves 5 and 15 (FIGS. 2 to 4) is also limited accordingly. In this way, it is possible to determine during the assembly of the control valve unit 28 for which maximum nominal flow rate the control valve unit 28 is to be designed. Different sizes of control valve units 28 are therefore unnecessary.

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

A detail of the pistons 48, 68 is shown in FIG. They have a groove 98 on their outer circumference, in which an annular elastic seal 99 is inserted. This seal 99 largely fills the gap between the cylindrical outer surface of the pistons 48, 68 and the inner wall of the control chamber 47, 67 (FIG. 2). The seal 99 advantageously fulfills the task of reducing the leakage, because it decisively reduces the leakage of hydraulic fluid from the control chamber 47, 67 in the direction of the main valve of the control valves 5, 15.

11 shows the outer 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 FIG. 11 begins at a distance d from the base 90 (FIGS. 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. This different size of the individual openings 93 advantageously achieves the fact that the flow characteristic dependent on the valve lift can be defined as desired by defining the individual distances d, d ', d "etc., so that the flow characteristic can be optimally adapted to the respective needs. ,

12a and 12b show further possible details of openings 93. An opening 93 is shown in FIG. 12a, the root 93 w of which begins analogously to FIG. 11 at a certain distance from the base 90. The depth of such an opening, but also the width, advantageously follow a dimensioning rule, which is 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, i.e. it obeys the following formula: A = k ^' y 2.5

In this formula, k is a proportionality factor.

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

13 shows a boundary line of an opening 93 in a particularly advantageous shape. In the area of the root of the opening 93, this opening 93 has a radius of, for example, 1 mm. A 180-degree arc is followed by curved boundary lines. By designing these boundary lines, special flow characteristics can be achieved.

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

The control valve unit 28 according to the invention was initially described in connection with FIG. 1. The pressure sensors 18 and 23 required for this type of control have not been shown in the other figures because the prior art already provides models for this. The same applies to the temperature sensor.

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 operating mode mentioned in the description for FIG. 1. Thus, the control valve unit 28 according to the invention can also be used with any other type of construction, with for example, even if the pump 10 is speed-controlled, which also entails another control principle for the control valve unit 28.

Claims

claims

1. Control valve unit (28) for a hydraulic elevator, which contains control valves (5, 15) and pilot valves (5 _V , 15 _v ), with which the flow of hydraulic oil from a tank (11) to an elevator car (1) driving lifting cylinder (3) or from the lifting cylinder (3) to the tank (11) can be controlled, whereby for an upward travel of the elevator car (1) the hydraulic piston by means of a pump (10) driven by an electric motor (12) from the tank (11) via the control valve unit (28) can be conveyed to the lifting cylinder (3) and for a downward movement of the pull-out cabin (1) the hydraulic piston can be conveyed to the tank (11) via the control valve unit (28), characterized in that for controlling the upward movement and the downward movement of the elevator car (1 ) there is a single pilot-controllable control valve (5, 15), each of which acts both as a check valve and as a proportional valve.

2. Control valve unit (28) according to claim 1, characterized in that in each of the control valves (5, 15) there is a single throttle body (35; 55) which is displaceable relative to a seat (36; 56).

3. Control valve unit (28) according to claim 2, characterized in that on the throttle body (35; 55) act on the one hand a return spring (37; 57) and on the other hand a pilot valve (5 _v ; 15 _v ), each of which by an electrically controllable proportional magnet (5; 15 _M ) can be actuated.

4. Control valve unit (28) according to claim 3, characterized gekennzeiclmet that when the control valve controlling the upward travel (15) whose 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, characterized in that when the downward control valve (5) whose 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, characterized in that the throttle body (35) of the downward control valve (5) and the throttle body (55) of the upward control valve (15) have the same shape and dimensions.

7. Control valve unit (28) according to claim 6, characterized in that when controlling the downward control valve (5) the power transmission from its pilot valve (5 _V ) by means of a against a main valve control spring (49) piston (48) via a control rod ( 50) on a counter piston (38) which moves the throttle body (35) via an adjusting rod (39) attached to it, the diameter of the counter piston (38) being equal to the diameter of the throttle body (35).

8. Control valve unit (28) according to claim 6, characterized in that when controlling the upward control valve (15) the power transmission from its pilot valve (15 _v ) by means of a against a main valve control spring (69) piston (68) via a control rod ( 70) on the throttle body (55) and that the throttle body (55) is firmly connected to an opposing piston (58) via an actuating rod (59), the diameter of the opposing piston (58) being equal to the diameter of the throttle body (55).

9. Control valve unit (28) according to claim 7 or 8, characterized in that the piston (48; 68) has on its outer circumference a groove (98) into which an elastic seal (99) is inserted.

10. Control valve unit (28) according to claim 7 or 8, characterized in that the throttle body (35; 55) facing surface of the counter body (38; 58) has the shape of a truncated cone.

11. Control valve unit (28) according to claim 10, characterized in that the lateral surface of the truncated cone (80) forms an angle a of approximately 15 to 25 degrees against a surface perpendicular to the longitudinal axis.

12. Control valve unit (28) according to one of claims 2 to 11, characterized in that the throttle bodies (35; 55) are formed from a base (90) and an adjoining cylinder (91), in the outer surface (92) of which openings ( 93) are milled.

13. Control valve unit (28) according to claim 11, characterized in that the openings (93) are at least partially V-shaped.

14. Control valve unit (28) according to claim 11, characterized in that the openings (93) have a cup-shaped shape.

15. Control valve unit (28) according to claim 11, characterized in that the openings (93) are stepped.

16. Control valve unit (28) according to one of claims 7 or 8 to 15, characterized in that means (95, 96; 97) are provided with which the path of the piston (48; 68) can be limited.

17. Control valve unit (28) according spoke 16, characterized in that the path is limited by a snap ring (96) which can be inserted into one of several in the cylindrical inner wall of control chambers (47; 67) pierced ring grooves (95).

18. Control valve unit (28) according to claim 16, characterized in that in the control chamber (47; 67) a cylindrical spacer ring (97) can be used, the outer diameter of which is slightly smaller than the diameter of the control chamber (47; 67) and by which Length of the stroke limitation can be determined.