EP0713816B1 - Hydraulic system for controlling rotation of a railroad car body and featuring an actuator depressurizing device - Google Patents
Hydraulic system for controlling rotation of a railroad car body and featuring an actuator depressurizing device Download PDFInfo
- Publication number
- EP0713816B1 EP0713816B1 EP95118463A EP95118463A EP0713816B1 EP 0713816 B1 EP0713816 B1 EP 0713816B1 EP 95118463 A EP95118463 A EP 95118463A EP 95118463 A EP95118463 A EP 95118463A EP 0713816 B1 EP0713816 B1 EP 0713816B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- hydraulic
- valve
- depressurizing
- supply line
- drain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000012530 fluid Substances 0.000 claims description 10
- 230000004044 response Effects 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 description 7
- 230000001276 controlling effect Effects 0.000 description 5
- 238000011144 upstream manufacturing Methods 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000003134 recirculating effect Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
- B61F5/00—Constructional details of bogies; Connections between bogies and vehicle underframes; Arrangements or devices for adjusting or allowing self-adjustment of wheel axles or bogies when rounding curves
- B61F5/02—Arrangements permitting limited transverse relative movements between vehicle underframe or bolster and bogie; Connections between underframes and bogies
- B61F5/22—Guiding of the vehicle underframes with respect to the bogies
Definitions
- the present invention relates to a hydraulic system for controlling rotation of a railroad car body.
- Variable-trim railroad cars are known to present a body supported on trucks and rotatable about a longitudinal axis. When cornering, the body is rotated inwards of the curve to at least partially compensate the centrifugal force produced and so provide for improved passenger comfort.
- the body is rotated by means of a hydraulic system substantially comprising a tank; a motor pump; a number of hydraulic actuators, normally two for each truck; and a solenoid valve for controlling supply to the actuators, and which in turn is controlled by an electronic processing unit on the basis of input signals from sensors on the car.
- a hydraulic system substantially comprising a tank; a motor pump; a number of hydraulic actuators, normally two for each truck; and a solenoid valve for controlling supply to the actuators, and which in turn is controlled by an electronic processing unit on the basis of input signals from sensors on the car.
- the system is also known to feature an actuator depressurizing device for restoring the body to the center position even in the event of a fault, e.g. jamming of the solenoid valve, which would otherwise prevent correct control of the actuators.
- actuator depressurizing devices normally comprise relatively complex circuitry, which means high cost, extra weight and bulk, and poor reliability.
- a hydraulic system for controlling rotation of a railroad car body comprising:
- Number 1 in the accompanying drawing indicates a hydraulic system for controlling rotation of a railroad car body 2 about a longitudinal axis A of the car.
- System 1 substantially comprises a first pair of front hydraulic cylinders 3a, 3b; a second pair of rear hydraulic cylinders 4a, 4b; and a hydraulic unit 5 for generating hydraulic power and operating said cylinders.
- the cylinders in each pair are located on either side of body 2, on the left and right side respectively, and are interposed between the body and a structural element 6 supported, conveniently by means of an elastic suspension, on the truck (not shown) of the car.
- Cylinders 3a, 3b, 4a, 4b are all single-acting types.
- Rotation axis A is defined by a known articulated parallelogram mechanism (not shown) connecting body 2 to structural element 6.
- Hydraulic unit 5 substantially comprises a hydraulic fluid tank 7; a motor pump assembly 8 for generating hydraulic power; and a hydraulic assembly 9 for controlling cylinders 3a, 3b and 4a, 4b.
- motor pump assembly 8 comprises a three-stroke, asynchronous electric motor 10; a pressure-compensated, variable-displacement main pump 12 and a fixed-displacement auxiliary pump 13, both driven by motor 10 and intake-connected to tank 7.
- a supply line 14 for supplying assembly 9 is connected to pump 12, which presents a pressure compensator for reducing its displacement on reaching a predetermined operating pressure of, say, 30 MPa.
- Pump 12 also presents a drain line 15 drain-connected to tank 7 and fitted with a low-pressure filter 16 presenting an electric clogging indicator 17 and a bypass valve 18.
- a conduit 19 for loading the system is connected to drain line 15, and presents a one-way valve 20 and an inlet filter 21.
- pump 13 The delivery side of pump 13 is connected by a recirculating line 31 to a heat exchanger 32 presenting a power fan 33, and then to tank 7; and pump 13 provides for circulating a large quantity of fluid, but for a low pressure of, say, 0.3 MPa.
- Control assembly 9 is connected to motor pump assembly 8 by supply line 14, and comprises, at the inlet and in series along line 14, a high-pressure filter 24 with an electric clogging indicator 25, and a non-return valve 23.
- Control assembly 9 also comprises a four-way, open-center, electrohydraulic servovalve 26, which presents an inlet 27 connected to supply line 14, a drain 28 connected to a drain line 29 in turn connected to tank 7, and two outlets 30a, 30b connected respectively to left cylinders 3a, 4a and right cylinders 3b, 4b, so that the two cylinders on each side are operated in parallel with the work chambers constantly at the same pressure.
- Servovalve 26 provides for selectively connecting cylinders 3a, 4a and 3b, 4b to supply line 14 and drain line 29 in response to electric signals from a control unit C.
- a diaphragm accumulator 34 is connected to supply line 14, between non-return valve 23 and inlet 27 of servovalve 26, by a line 35, which is fitted with a pressure switch 36 for generating an enabling signal when the pressure along supply line 14 exceeds a predetermined minimum threshold value sufficient to ensure correct operation of system 1.
- a depressurizing conduit 37 with a calibrated orifice 38 extends from supply line 14; and, upstream from orifice 38, conduit 37 is connected to drain line 29 by a conduit 39 fitted with a hand-operated drain valve 40.
- conduit 37 Downstream from orifice 38, conduit 37 is connected to drain line 29 by two parallel conduits 43, 44.
- Conduit 43 is fitted with a pressure regulating valve 45 set to open when the inlet pressure reaches a predetermined threshold value; and
- conduit 44 is fitted with a two-way, two-position, normally-open electric distributor 46 which closes in the presence of an electric enabling signal received from unit C and indicating correct operation of the system.
- Control assembly 9 also comprises a pair of disabling valves 47, which are substantially hydraulically-operated bypass valves, with respective inlets 48 connected by calibrated orifices 49 to respective outlets 30a, 30b of servovalve 26, and respective outlets 50 connected to drain line 29.
- each disabling valve 47 comprises a hollow body 53 presenting, at axial end 54, inlet 48 surrounded coaxially by a substantially conical sealing seat 55; and a movable member 56 sliding axially inside body 53.
- body 53 also presents an auxiliary drive inlet 58 connected by a drive conduit 59 to conduit 37 downstream from orifice 38.
- Member 56 is movable between a closed position in which it cooperates with seat 55, and an open position in which it is detached from seat 55 to hydraulically connect inlet 48 and outlet 50.
- Movable member 56 is pushed into the open position by the elastic force of a spring 60 interposed between member 56 and end 54 of body 53, and is also subjected to hydraulic force in the opening direction, due to the pressure at inlet 48, and to hydraulic force in the closing direction, due to the pressure at drive inlet 58.
- the resultant of the hydraulic forces is normally opposite and prevails over the elastic force to keep the valve in the closed position.
- Electric distributor 46 and valves 47 define a device 61 for simultaneously depressurizing actuators 3a, 3b, 4a, 4b.
- control assembly 9 also comprises a two-way, normally-open valve 64 for bypass starting motor pump assembly 8, and which is located along a conduit 63 connecting supply line 14, immediately downstream from filter 24, to drain line 29.
- Valve 64 comprises a body 65 presenting an inlet 67 and an outlet 68 communicating respectively with supply line 14 and drain line 29; and a ball 69 movable inside body 65 and cooperating in sealing manner with a seat 66 interposed between inlet 67 and outlet 68.
- Ball 69 is loaded and detached from seat 66 by a spring 70, and is subjected to the resultant of the hydraulic forces exerted by flow through valve 64; which resultant, as a consequence of the load loss through the valve, tends to push ball 69 against seat 66, and increases in intensity alongside an increase in flow.
- Spring 70 is so sized that valve 64 switches from open to closed when the flow through it reaches a predetermined threshold value equal to the maximum-displacement flow of pump 12 at close to the rated speed (e.g. 75%) of motor 10.
- accumulator 34 is discharged; distributor 46 is de-energized and connects supply line 14 to drain line 29; and valve 64 is opened by spring 70.
- valve 64 When power is supplied to turn on electric motor 10, this operates pumps 12 and 13 connected to it; and pump 12, which is in the maximum-displacement condition, supplies line 14 with a quantity of fluid increasing alongside an increase in the speed of motor 10. Since the pumped fluid is recirculated into tank 7 via distributor 46 and valve 64, the pressure in supply line 14 remains low, and, since the hydraulic resistance of valve 64 is less than that of distributor 46, the fluid pumped by pump 12 flows mainly through valve 64. When, as the speed of the motor increases, the flow through valve 64 reaches the above threshold value, the valve closes, and the pressure along supply line 14 increases to help keep valve 64 closed.
- distributor 46 In the presence of an electric enabling signal from the system control unit, distributor 46 also closes; the supply line is pressurized further; and, servovalve 26 being in the central position, accumulator 34 is charged. This stage continues until the set pressure of the compensator of pump 12 is reached, at which point, the displacement of the pump is reduced to the minimum value required to compensate for leakage of the system and maintain a constant operating pressure.
- distributor 46 is assumed to close after valve 64. In actual practice, however, the opposite may occur, with no substantial change in the operation of the system, the only difference being that, in the event distributor 46 closes before valve 64, the flow generated by pump 12 flows entirely through valve 64 and closes it when the above flow threshold value is reached.
- motor 10 also powers fixed-displacement pump 13, this also contributes towards the loading torque demanded of the motor.
- pump 13 operates permanently at low pressure, very little torque is required to operate it, so that motor 10 may be low-load started at all times.
- control unit C of system 1 calculates an optimum or reference angular position of body 2, and supplies servovalve 26 with a control signal as a function of the error between the reference position and the actual angular position of body 2 as detected by sensors on the body; the control signal shifts the slide valve in the required direction from the center position to regulate flow to and from the hydraulic cylinders and rotate the body; and, as the actual angular position, as detected by the sensors on the body, nears the reference value, the error and consequently the flow regulated by servovalve 26 are gradually reduced, until flow is eventually cut off when the body reaches the required angular position.
- distributor 46 and pressure regulating valve 45 are closed; and disabling valves 47 are closed by virtue of the drive pressure of the valves being equal to the supply pressure.
- Such a pressure is always greater than the pressure of outlets 30a, 30b of servovalve 26, and the resultant of the pressure forces on movable member 56 of disabling valves 47 is always greater than the opening force generated by spring 60.
- pump 12 is filtered by high-pressure filter 24 to ensure clean fluid is supplied to control assembly 9 and cylinders 3a, 3b, 4a, 4b; and filter 16 is fitted to drain line 15 of pump 12, which is the major source of contamination.
- Pump 13 pumps a continuous flow of hydraulic fluid from tank 7 through heat exchanger 32 to dispose of the heat generated by the system.
- non-return valve 23 closes, and the part of the system downstream from valve 23 is pressurized by accumulator 34, thus enabling correct operation of the system until the pressurized fluid reserve in accumulator 34 runs out.
- bypass starting valve 64 opens to permit depressurized start-up when electric motor 10 is again supplied.
- device 61 is extremely straightforward, economical, and intrinsically highly reliable due to the simplicity and small number of component parts.
- servovalve 26 may be replaced by a proportional solenoid valve.
Description
- The present invention relates to a hydraulic system for controlling rotation of a railroad car body.
- Variable-trim railroad cars are known to present a body supported on trucks and rotatable about a longitudinal axis. When cornering, the body is rotated inwards of the curve to at least partially compensate the centrifugal force produced and so provide for improved passenger comfort.
- The body is rotated by means of a hydraulic system substantially comprising a tank; a motor pump; a number of hydraulic actuators, normally two for each truck; and a solenoid valve for controlling supply to the actuators, and which in turn is controlled by an electronic processing unit on the basis of input signals from sensors on the car.
- The system is also known to feature an actuator depressurizing device for restoring the body to the center position even in the event of a fault, e.g. jamming of the solenoid valve, which would otherwise prevent correct control of the actuators. Such devices normally comprise relatively complex circuitry, which means high cost, extra weight and bulk, and poor reliability.
- It is an object of the present invention to provide a system of the above type featuring a particularly straightforward, reliable actuator depressurizing device.
- According to the present invention, there is provided a hydraulic system for controlling rotation of a railroad car body, and comprising:
- a hydraulic fluid tank;
- a motor pump assembly connected to the tank and to a supply line;
- two pairs of hydraulic actuators on either side of the body, and for exerting mechanical force on the body to rotate it;
- a solenoid valve for selectively connecting said pairs of hydraulic actuators to the supply line and to a drain, in response to electric control signals; and
- means for depressurizing the actuators in each of said pairs;
- A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying hydraulic diagram.
-
Number 1 in the accompanying drawing indicates a hydraulic system for controlling rotation of arailroad car body 2 about a longitudinal axis A of the car. -
System 1 substantially comprises a first pair of fronthydraulic cylinders 3a, 3b; a second pair of rearhydraulic cylinders hydraulic unit 5 for generating hydraulic power and operating said cylinders. As shown schematically forfront cylinders 3a, 3b only, the cylinders in each pair are located on either side ofbody 2, on the left and right side respectively, and are interposed between the body and astructural element 6 supported, conveniently by means of an elastic suspension, on the truck (not shown) of the car.Cylinders - Rotation axis A is defined by a known articulated parallelogram mechanism (not shown) connecting
body 2 tostructural element 6. -
Hydraulic unit 5 substantially comprises ahydraulic fluid tank 7; a motor pump assembly 8 for generating hydraulic power; and a hydraulic assembly 9 for controllingcylinders - More specifically, motor pump assembly 8 comprises a three-stroke, asynchronous
electric motor 10; a pressure-compensated, variable-displacementmain pump 12 and a fixed-displacementauxiliary pump 13, both driven bymotor 10 and intake-connected totank 7. - A
supply line 14 for supplying assembly 9 is connected topump 12, which presents a pressure compensator for reducing its displacement on reaching a predetermined operating pressure of, say, 30 MPa.Pump 12 also presents adrain line 15 drain-connected totank 7 and fitted with a low-pressure filter 16 presenting an electric clogging indicator 17 and a bypass valve 18. Aconduit 19 for loading the system is connected todrain line 15, and presents a one-way valve 20 and aninlet filter 21. - The delivery side of
pump 13 is connected by arecirculating line 31 to aheat exchanger 32 presenting apower fan 33, and then to tank 7; andpump 13 provides for circulating a large quantity of fluid, but for a low pressure of, say, 0.3 MPa. - Control assembly 9 is connected to motor pump assembly 8 by
supply line 14, and comprises, at the inlet and in series alongline 14, a high-pressure filter 24 with anelectric clogging indicator 25, and a non-return valve 23. - Control assembly 9 also comprises a four-way, open-center,
electrohydraulic servovalve 26, which presents aninlet 27 connected tosupply line 14, a drain 28 connected to adrain line 29 in turn connected totank 7, and twooutlets left cylinders 3a, 4a andright cylinders cylinders line 14 anddrain line 29 in response to electric signals from a control unit C. - A
diaphragm accumulator 34 is connected tosupply line 14, between non-return valve 23 andinlet 27 ofservovalve 26, by aline 35, which is fitted with apressure switch 36 for generating an enabling signal when the pressure alongsupply line 14 exceeds a predetermined minimum threshold value sufficient to ensure correct operation ofsystem 1. - Upstream from
inlet 27 ofservovalve 26, a depressurizingconduit 37 with a calibratedorifice 38 extends fromsupply line 14; and, upstream fromorifice 38,conduit 37 is connected todrain line 29 by aconduit 39 fitted with a hand-operated drain valve 40. - Downstream from
orifice 38,conduit 37 is connected todrain line 29 by twoparallel conduits 43, 44. Conduit 43 is fitted with a pressure regulating valve 45 set to open when the inlet pressure reaches a predetermined threshold value; andconduit 44 is fitted with a two-way, two-position, normally-openelectric distributor 46 which closes in the presence of an electric enabling signal received from unit C and indicating correct operation of the system. - Control assembly 9 also comprises a pair of disabling
valves 47, which are substantially hydraulically-operated bypass valves, withrespective inlets 48 connected bycalibrated orifices 49 torespective outlets respective outlets 50 connected todrain line 29. - More specifically, each disabling
valve 47 comprises ahollow body 53 presenting, ataxial end 54,inlet 48 surrounded coaxially by a substantially conical sealing seat 55; and amovable member 56 sliding axially insidebody 53. At the oppositeaxial end 57,body 53 also presents anauxiliary drive inlet 58 connected by adrive conduit 59 to conduit 37 downstream fromorifice 38.Member 56 is movable between a closed position in which it cooperates with seat 55, and an open position in which it is detached from seat 55 to hydraulically connectinlet 48 andoutlet 50. -
Movable member 56 is pushed into the open position by the elastic force of aspring 60 interposed betweenmember 56 andend 54 ofbody 53, and is also subjected to hydraulic force in the opening direction, due to the pressure atinlet 48, and to hydraulic force in the closing direction, due to the pressure atdrive inlet 58. In use, the resultant of the hydraulic forces is normally opposite and prevails over the elastic force to keep the valve in the closed position. -
Electric distributor 46 andvalves 47 define adevice 61 for simultaneously depressurizingactuators - Finally, control assembly 9 also comprises a two-way, normally-open valve 64 for bypass starting motor pump assembly 8, and which is located along a conduit 63 connecting
supply line 14, immediately downstream fromfilter 24, to drainline 29. Valve 64 comprises a body 65 presenting an inlet 67 and an outlet 68 communicating respectively withsupply line 14 anddrain line 29; and aball 69 movable inside body 65 and cooperating in sealing manner with a seat 66 interposed between inlet 67 and outlet 68.Ball 69 is loaded and detached from seat 66 by a spring 70, and is subjected to the resultant of the hydraulic forces exerted by flow through valve 64; which resultant, as a consequence of the load loss through the valve, tends to pushball 69 against seat 66, and increases in intensity alongside an increase in flow. Spring 70 is so sized that valve 64 switches from open to closed when the flow through it reaches a predetermined threshold value equal to the maximum-displacement flow ofpump 12 at close to the rated speed (e.g. 75%) ofmotor 10. -
System 1 operates as follows. - Initially,
accumulator 34 is discharged;distributor 46 is de-energized and connectssupply line 14 todrain line 29; and valve 64 is opened by spring 70. - When power is supplied to turn on
electric motor 10, this operatespumps pump 12, which is in the maximum-displacement condition,supplies line 14 with a quantity of fluid increasing alongside an increase in the speed ofmotor 10. Since the pumped fluid is recirculated intotank 7 viadistributor 46 and valve 64, the pressure insupply line 14 remains low, and, since the hydraulic resistance of valve 64 is less than that ofdistributor 46, the fluid pumped bypump 12 flows mainly through valve 64. When, as the speed of the motor increases, the flow through valve 64 reaches the above threshold value, the valve closes, and the pressure alongsupply line 14 increases to help keep valve 64 closed. - In the presence of an electric enabling signal from the system control unit,
distributor 46 also closes; the supply line is pressurized further; and, servovalve 26 being in the central position,accumulator 34 is charged. This stage continues until the set pressure of the compensator ofpump 12 is reached, at which point, the displacement of the pump is reduced to the minimum value required to compensate for leakage of the system and maintain a constant operating pressure. - In the above description of the start-up transient condition,
distributor 46 is assumed to close after valve 64. In actual practice, however, the opposite may occur, with no substantial change in the operation of the system, the only difference being that, in theevent distributor 46 closes before valve 64, the flow generated bypump 12 flows entirely through valve 64 and closes it when the above flow threshold value is reached. - Since
motor 10 also powers fixed-displacement pump 13, this also contributes towards the loading torque demanded of the motor. Aspump 13, however, operates permanently at low pressure, very little torque is required to operate it, so thatmotor 10 may be low-load started at all times. - Under normal operating conditions, when the car is cornering, control unit C of
system 1 calculates an optimum or reference angular position ofbody 2, and supplies servovalve 26 with a control signal as a function of the error between the reference position and the actual angular position ofbody 2 as detected by sensors on the body; the control signal shifts the slide valve in the required direction from the center position to regulate flow to and from the hydraulic cylinders and rotate the body; and, as the actual angular position, as detected by the sensors on the body, nears the reference value, the error and consequently the flow regulated byservovalve 26 are gradually reduced, until flow is eventually cut off when the body reaches the required angular position. - Under normal operating conditions,
distributor 46 and pressure regulating valve 45 are closed; and disablingvalves 47 are closed by virtue of the drive pressure of the valves being equal to the supply pressure. Such a pressure is always greater than the pressure ofoutlets servovalve 26, and the resultant of the pressure forces onmovable member 56 of disablingvalves 47 is always greater than the opening force generated byspring 60. - During operation, the delivery of
pump 12 is filtered by high-pressure filter 24 to ensure clean fluid is supplied to control assembly 9 andcylinders line 15 ofpump 12, which is the major source of contamination. -
Pump 13 pumps a continuous flow of hydraulic fluid fromtank 7 throughheat exchanger 32 to dispose of the heat generated by the system. - In the event of a temporary power failure - e.g. when traveling along a stretch of line with no electricity supply, due to a breakdown or repair or maintenance work - motor pump assembly 8 stops, non-return valve 23 closes, and the part of the system downstream from valve 23 is pressurized by
accumulator 34, thus enabling correct operation of the system until the pressurized fluid reserve inaccumulator 34 runs out. - Since
pump 12 is idle at this stage, the part ofsystem 1 upstream from non-return valve 23 is depressurized due to internal leakage of the pump; and bypass starting valve 64 opens to permit depressurized start-up whenelectric motor 10 is again supplied. - To disable
system 1, power supply toelectric motor 10 is cut off andelectric distributor 46 is de-energized; the part of the system upstream from non-return valve 23 is therefore depressurized as described above, and valve 64 opens to prepare the system for the next start-up; and, at the same time, the opening ofdistributor 46 connectsaccumulator 34 to drainline 29 to depressurize the system as a whole. More specifically,drive lines 59 of disablingvalves 47 are also connected to the drain, so thatvalves 47 open to drain all fourcylinders servovalve 26 jamming in other than the central position, the cylinders, in the absence ofdevice 61, would keep the body tilted even at the end of the curve, the disadvantages of which are obvious.Device 61, on the other hand, provides for simultaneously depressurizing all the cylinders to restore the body to the upright position. - The advantages of
system 1 according to the present invention will be clear from the foregoing description. - In particular,
device 61 is extremely straightforward, economical, and intrinsically highly reliable due to the simplicity and small number of component parts. - Clearly, changes may be made to
system 1 as described and illustrated herein without, however, departing from the scope of the present invention. - In particular, servovalve 26 may be replaced by a proportional solenoid valve.
Claims (4)
- A hydraulic system (1) for controlling rotation of a railroad car body (2), and comprising:a hydraulic fluid tank (7);a motor pump assembly (8) connected to the tank (7) and to a supply line (14);two pairs of hydraulic actuators (3a, 4a; 3b, 4b) on either side of the body (2), and for exerting mechanical force on the body to rotate it;a solenoid valve (26) for selectively connecting said pairs of hydraulic actuators (3a, 4a; 3b, 4b) to the supply line (14) and to a drain (29), in response to electric control signals; andmeans (61) for depressurizing the actuators (3a, 4a; 3b, 4b) in each of said pairs;
characterized in that said depressurizing means (61) comprise two hydraulically driven disabling valves (47), each interposed between a said pair of actuators (3a, 4a; 3b, 4b) and the drain (29), said valves (47) being normally open, and presenting respective drive lines (59) connected to said supply line (14); and valve means (46) for depressurizing said drive lines (59). - A system as claimed in Claim 1, characterized in that said valve means (46) for depressurizing said drive lines (59) comprise a two-way electric distributor (46) for connecting said drive lines (59) to the drain (29) in the absence of an electric enabling signal.
- A system as claimed in Claim 1 or 2, characterized in that said drive lines (59) and said electric distributor (46) are connected to said supply line (14) by a depressurizing conduit (37) presenting a calibrated orifice (38).
- A system as claimed in any one of the foregoing Claims, characterized in that each of said disabling valves (47) comprises a movable member (56) sliding between a closed position and an open position; said movable member (56) being forced by elastic means (60) into said open position, and being subjected to the resultant of a first hydraulic force acting in the opening direction and due to the inlet pressure of said disabling valve (47), and a second hydraulic force acting in the closing direction and due to the drive pressure.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT94TO000954A IT1267625B1 (en) | 1994-11-25 | 1994-11-25 | HYDRAULIC ROTATION CONTROL SYSTEM OF A RAILWAY BOX WITH ACTUATORS DEPRESSURIZATION DEVICE |
ITTO940954 | 1994-11-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0713816A1 EP0713816A1 (en) | 1996-05-29 |
EP0713816B1 true EP0713816B1 (en) | 1999-02-17 |
Family
ID=11412925
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95118463A Expired - Lifetime EP0713816B1 (en) | 1994-11-25 | 1995-11-23 | Hydraulic system for controlling rotation of a railroad car body and featuring an actuator depressurizing device |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0713816B1 (en) |
DE (1) | DE69507867T2 (en) |
ES (1) | ES2131745T3 (en) |
IT (1) | IT1267625B1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19618747C1 (en) * | 1996-05-09 | 1997-12-11 | Siemens Ag | Pantograph |
US6397129B1 (en) * | 1999-11-01 | 2002-05-28 | Bombardier Inc. | Comfort monitoring system and method for tilting trains |
FI125345B (en) * | 2012-08-31 | 2015-08-31 | Vr Yhtymä Oy | Tilt control |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1346273A (en) * | 1962-06-28 | 1963-12-20 | Fr D Applic Electro Hydrauliqu | Method for the hydraulic stabilization of a body of a vehicle with articulated undercarriages and equipment allowing the implementation of such a method, in particular on railway vehicles |
US4363277A (en) * | 1980-05-13 | 1982-12-14 | Dofasco Inc. | Stabilizing high speed railway truck safety device |
-
1994
- 1994-11-25 IT IT94TO000954A patent/IT1267625B1/en active IP Right Grant
-
1995
- 1995-11-23 DE DE69507867T patent/DE69507867T2/en not_active Expired - Fee Related
- 1995-11-23 EP EP95118463A patent/EP0713816B1/en not_active Expired - Lifetime
- 1995-11-23 ES ES95118463T patent/ES2131745T3/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
ITTO940954A0 (en) | 1994-11-25 |
IT1267625B1 (en) | 1997-02-07 |
ES2131745T3 (en) | 1999-08-01 |
ITTO940954A1 (en) | 1996-05-25 |
DE69507867D1 (en) | 1999-03-25 |
EP0713816A1 (en) | 1996-05-29 |
DE69507867T2 (en) | 1999-12-30 |
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