Irreversible, high-efficiency drive chain, preferably for taps

Abstract

The present invention relates to a bidirectional anti-rotation device (200) adapted to transmit a rotational torque from an actuator (100) to a shaft (2). The bidirectional anti-rotation device (200) is such that when the shaft (2) receives a torque from a component other than a rotating drive system (10), a cam (4) clamps one of every two rollers (5) against a housing (0), thus blocking any rotational movement of the shaft (2). Meanwhile, a torque applied to the rotating drive system (10) causes, successively, through circumferential clearances (13) and (63), the separation of one of every two rollers (5) to release the cam (4) from contact with the rollers (5). Then, through angular clearances (12) and (62), a key (3) is driven into rotation, thus rotating the shaft (2) relative to the housing (0). Figure for the abbreviated version: Fig. 2

Description

Title of the invention: Irreversible and high-performance kinematic chain, preferably for a tap FIELD OF THE INVENTION

[0001] The invention relates generally to the field of mechanical connections, more particularly that of industrial valves and devices adapted to the control of systems such as gate valves, globe valves for valves with a translating stem, and any other type of valve, for example valves with a rotating stem such as butterfly valves or spherical or cylindrical rotary valves. STATE OF THE ART

[0002] An industrial valve with a translational stem generally consists of an actuator, a means for converting the transmitted rotational movement into a translational movement and a shutter. Typically, these elements are an electric motor coupled to a manual emergency control, which rotates a stem nut, which moves a threaded stem in translation by screw effect, driving in translation at its other end the shutter of the valve whose function is to close a pipe.

[0003] To close the valve and thus stop the flow of fluid, the actuator is driven so as to press the shutter against the seat(s) of the valve located at one end of the travel of the shutter and in the pipe. To open the valve, the actuator is driven in a reverse movement, to disengage the shutter from the seat(s) and consequently release the flow of fluid.

[0004] Such a valve must be able to ensure permanent closure, that is to say prevent any unwanted rise of the shutter after closure, due for example to the bottom effect on the stem induced by the pressure of the fluid in the case of the gate valve, or any untimely opening of the shutter due to the thrust of the fluid, in the case of globe valves or valves with a rotating stem. Similarly, the valve must be able to maintain its open position by compensating for the effects of the self-weight of the stem and the shutter in the case of the valve with a translating stem, or the effects of the thrust of the fluid in the case of the valve with a rotating stem.

[0005] To obtain these results in a valve with a translational stem, the means for converting the rotational movement of the actuator into translational movement of the shutter must provide for the irreversibility of this conversion and therefore of the kinematic chain constituted by all the components of the valve. In addition, this irreversibility must exist downstream of the actuator, so as to be able to remove it for maintenance or other operations, while retaining the irreversibility of the valve. State-of-the-art sliding stem valves, for example, use a threaded stem and trapezoidal nut assembly for this purpose, so that only the movement of the valve actuator allows the shutter to move.

[0006] However, such a tap screw-nut system only offers a low efficiency, of approximately 30%, due to the significant friction induced by this type of conversion means.

[0007] Other high-efficiency conversion means are known, but they are not suitable for this type of application due to their reversibility, which would allow the rod to rise and rotate the upstream elements. Statement of the invention

[0008] An aim of the invention is to remedy the aforementioned drawbacks, by proposing a bidirectional anti-backoff device adapted to drive a shaft in rotation, a device for irreversibly converting a rotational movement into a translational movement comprising such an anti-backoff device and a translational stem valve comprising such a device for converting a rotational movement into a translational movement, making it possible to effectively improve efficiency while offering the guarantee of the irreversibility of the kinematic chain downstream of the actuator.

[0009] To this end, the invention proposes a bidirectional anti-backoff device suitable for transmitting a rotational torque from an actuator to a shaft comprising:

[0010] - a casing arranged around a shaft, adapted to be rotatable around an axis of rotating and mobile in rotation relative to the casing;

[0011] - a key extending radially projecting from the shaft;

[0012] - a system for driving the shaft in rotation arranged inside the casing, the rotary drive system comprising: - a coupling device with the actuator comprising a central opening into which the shaft and the key are inserted, allowing angular play between the walls of the central opening and the key; - a ring, arranged opposite and at a distance from the coupling device, the ring comprising a central opening into which the shaft and the key are inserted, allowing angular play between the walls of the opening and the key; - a spacer, arranged between the coupling device and the ring, comprising a central opening into which the shaft and the key are inserted; - several rods extending from the coupling element to the ring through the spacer, so as to secure them in rotation;

[0013] - a shaft locking system arranged inside the casing, the system of shaft lock including: - a cam arranged around the shaft and comprising a housing receiving the key, the cam being capable of being driven by the key; - a plurality of rollers arranged circumferentially around the shaft between the rods, the rollers extending from the coupling device to the ring through the spacer so as to allow circumferential clearance at the coupling device, circumferential clearance at the spacer and circumferential clearance at the ring; - several compression springs arranged around the shaft, each spring comprising a compression axis perpendicular to the axis of each roller, the springs being fixed in the coupling device and in the ring, the springs being adapted to keep the rollers in contact with the cam, when they are at rest, at the rate of two springs per roller;

[0014] the bidirectional anti-backoff device being such that when the shaft receives a torque from a member other than the shaft rotation drive system, the cam wedges one roller out of two in abutment against the casing, thus blocking any rotational movement of the shaft, while a torque applied to the rotation drive system successively causes, thanks to the circumferential clearances, the separation of one roller out of two, in order to free the cam from contact with the rollers, then the rotation drive by the angular clearances of the key, and therefore the rotation of the shaft relative to the casing.

[0015] The invention also relates to a device for irreversibly converting a rotational movement into a translational movement, comprising a bidirectional anti-backoff device according to the invention, in which the shaft is a nut of a satellite roller screw.

[0016] The invention also relates to a device for irreversibly converting a rotational movement into a translational movement comprising: - a bidirectional anti-backoff device adapted to rotate a shaft according to the invention; - a conversion means configured to convert a rotational movement into a translational movement, the input shaft of the conversion device being driven directly or indirectly by the shaft.

[0017] The device for irreversibly converting a rotational movement into a translational movement according to the invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations: - the conversion means is a satellite roller screw or a ball screw; - a shock absorber configured to oppose the raising of the means of conversion when the output shaft of the conversion means is at the end of race ; - the shock absorber includes an elastic washer.

[0018] The invention also relates to an assembly comprising a tap, the tap comprising a rod and a shutter, configured so that the rod is driven in translation by the device for irreversibly converting a rotational movement into a translational movement according to the invention, so as to place the shutter in a stable position.

[0019] The assembly comprising a tap according to the invention is advantageously completed by the following characteristics, taken alone or in any of their technically possible combinations: - a mechanical connection, the mechanical connection being configured to prevent the transmission of a rotational movement by the rod to the device according to the invention; - the mechanical connection is a ball and socket finger connection, the finger being optionally configured to indicate the position of the tap stem; - the mechanical connection is a non-sliding pivot connection on the axle. DESCRIPTION OF FIGURES

[0020] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0021] [Fig. 1] illustrates a schematic view of a tap comprising the new kinematic chain according to the invention;

[0022] [Fig.2] schematically illustrates the bidirectional anti-backstop device;

[0023] [Fig.3] schematically illustrates a partial view of the bidirectional anti-backstop device;

[0024] [Fig.4] illustrates a schematic view of a tap according to one embodiment of the invention.

[0025] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0026] [Fig.l] illustrates a valve 1000 according to an embodiment of the invention. Such a valve makes it possible to close a pipe 600, the pipe 600 being able to contain any type of fluid, for example water or gas, within industrial installations, transport infrastructures or other types of circuit. The valve 1000 therefore comprises several elements forming a kinematic chain making it possible to close the pipe 600 to which it is connected. In particular, the valve 1000 comprises an actuator 100 emitting a rotational movement and connected to a device for irreversibly converting a rotational movement into a translational movement. 2000, the translational movement being applied to a closing assembly 500 of the pipe 600.

[0027] In a non-limiting manner and as visible in [Fig. 1], the pipe 600 extends along a first axis B and the valve 1000 extends along a second axis A perpendicular to the first axis B. The second axis A constitutes the main axis of the kinematic chain.

[0028] The actuator 100 is adapted to transmit or generate a rotational torque. It may be, for example, a manual steering wheel, an electric motor or any other means suitable for use for this purpose. This rotational torque is therefore transmitted to a device for irreversibly converting a rotational movement into a translational movement 2000, which thus moves the closing assembly 500, composed of a rod 501 and a shutter 502, in translation, into the open or closed position depending on the direction of rotation of the actuator 100, so as to open or close the pipe 600.

[0029] More precisely, the device for irreversibly converting a rotational movement into a translational movement 2000 comprises: - A bidirectional anti-backoff device 200 adapted to drive in rotation a shaft 2 extending longitudinally along the second axis A; - A conversion means 300 configured to convert the rotational movement of the shaft 2 into a translational movement;

[0030] Figures 2 and 3 illustrate a preferred embodiment of a bidirectional backstop device 200 adapted to drive the shaft 2 in rotation in a bidirectional and irreversible manner. The bidirectional backstop device 200 comprises a casing 0 arranged around a shaft 2 movable in rotation relative to the casing 0. In the shaft 2 is inserted, for example in a keyway, a key 3 which extends along the shaft 2 and projects from the shaft 2 over a portion of its length.

[0031] The bidirectional anti-backoff device 200 consists of a rotation drive system 10 around the second axis A of the shaft 2. The rotation drive system 10 is advantageously constituted by a coupling device 1 configured to couple with the actuator 100. The coupling device 1 is preferably a cylindrical part, comprising a central opening 11 housing the shaft 2 and the key 3, while allowing a first angular clearance 12 between the walls of the central opening 11 and the key 3.

[0032] Opposite and at a distance from the coupling device 1 is arranged a ring 6, comprising a central opening 61 in which the shaft 2 and the key 3 are inserted, allowing a second angular clearance 62 between the walls of the opening and the key 3, preferably of an amplitude identical to or close to that of the angular clearance 12.

[0033] At least one spacer 7, preferably two spacers 7, are arranged between the coupling device 1 and the ring 6, and each spacer 7 also comprises a central opening 71 in which the shaft 2 and the key 3 are inserted. Several rods 8 extend from the coupling element 1 to the ring 6 passing through the spacers 7 via orifices comprising a circumferential clearance 74, so as to secure the rotational drive system 10, that is to say that the coupling device 1 and the ring 6 are secured to each other in rotation or in translation and in rotation, and that the spacers 7 are secured in rotation with the coupling device 1 and the ring 6. The rods 8 can be of circular or polygonal profile to offer more rigidity to the rotational drive system 10.

[0034] Between the casing 0 and the spacers 7 can be positioned ball bearings 75, which guide the spacers 7 in rotation inside the casing 0 and support the axial load of the weight of the bidirectional anti-backoff device 200. The spacers 7 and optionally the spacers 7 and the ball bearings 75 make it possible to center the shaft 2 in the casing 0 and therefore to make them coaxial with the axis A.

[0035] The bidirectional anti-backoff device 200 further comprises a locking system 20 for the shaft 2, arranged inside the casing 0 and composed of a cam 4, several rollers 5 and several springs 9.

[0036] The cam 4 is arranged around the shaft 2 and comprises a housing receiving the key 3, so that the cam 4 is able to be driven in rotation by the key 3 when the shaft 2 is in motion.

[0037] The rollers 5 are arranged circumferentially around the shaft 2, between the rods 8, the rollers 5 extending from the coupling device 1 towards the ring 6 by passing through the spacers 7 via a set of orifices each comprising a circumferential clearance 73. The end of the rollers 5 is inserted so as to allow a circumferential clearance 13 at the coupling device 1 and a circumferential clearance 63 at the ring 6, that is to say that the orifices of the coupling device 1 and of the ring 6 receiving the ends of the rollers 5 are of a diameter greater than that of the rollers 5. Similarly, the circumferential clearances 13 and 63 are preferably of a diameter less important than the diameter of the circumferential clearance 73 of the spacers 7.

[0038] The springs 9, for example compression springs, are arranged around the shaft 2, each spring 9 comprising a compression axis perpendicular to the axis C of each roller 5. The springs 9 are housed in the coupling device 1 and in the ring 6, and are adapted to keep the rollers 5 in contact with the cam 4 and the casing 0. There are therefore two springs 9 per roller 5. [Fig. 3] shows in particular a configuration of the springs 9 housed in the ring 6, so that four springs 9 apply a force opposite to a first direction of rotation on four rollers 5 and vice versa for the other springs 9 in the other direction of rotation.

[0039] The bidirectional anti-backstop device 200 therefore operates so that when the shaft 2 receives a torque from a member other than the rotational drive system 10 of the shaft 2, for example a torque from the conversion means 300, the cam 4, which receives the torque via the key 3, wedges one roller 5 out of two in abutment against the casing 0, blocking any rotational movement of the shaft 2, while a torque applied to the drive system 10 successively causes, thanks to the circumferential clearances 13 and 63, the separation of a roller 5 in order to free the cam 4 from contact with the rollers 5, then the rotational drive of the shaft 2 by the angular clearances 12 and 62 of the key 3, thus allowing the rotation of the shaft 2 relative to the casing 0. The spacers 7 are not immediately driven by the rods 8 during the separation 5 rollers thanks to the circumferential clearance 74.

[0040] The rotational torque of the shaft 2 is then transmitted to the means 300 for converting the rotational movement into translational movement. To carry out the transmission between the shaft 2 and the conversion means 300, any type of mechanical coupling can be used between the shaft 2 and an input shaft 301 of the conversion means 300, for example a mortise and tenon type connection. The function of the conversion means 300 is to transform the torque imposed by the shaft 2 into a tensile or compressive force (depending on the direction of rotation) on the rod 501. In the embodiment of [Fig. 4], the conversion means 300 is a satellite roller screw. The nut of the satellite roller screw corresponds to the input shaft 301 and the screw corresponds to an output shaft 302 of the conversion means 300. A satellite roller screw offers a high efficiency conversion compared to other means used in the prior art.

[0041] The translational movement of the conversion means 300 is transmitted to a tap stem 501, by a mechanical connection 50, for example a non-sliding pivot connection, or any other type of mechanical connection making it possible to prevent any transmission of a rotational movement of the tap stem to the output shaft 302. In the embodiment of [Fig. 4], the mechanical connection 50 is a finger ball joint type connection whose finger makes it possible to indicate the position of the tap 1000.

[0042] The rod 501 is preferably integral in translation with the shutter 502. The assembly formed by the rod 501 and the shutter 502 is thus translated in one direction or another along the axis A, according to the direction of rotation imposed by the actuator 100, in order to move the shutter 502 between two stable extreme positions, one closing the conduit and the other leaving the conduit free, these positions being respectively the open and closed configurations of the valve 1000.

[0043] In the embodiment of [Fig. 4], and with reference to [Fig. 1], the closing of the valve 1000 is carried out when an actuator 100 applies a torque to the coupling device 1 of the anti-drift device 200, which causes the shaft 2 to rotate relative to the casing 0 and to the axis A. The shaft 2 then drives the input shaft 301 of the conversion means 300, which causes the translation, towards the pipe 600 along the axis A, of the output shaft 302. The translation movement is transmitted by the mechanical connection 50 to the rod 501, which places the shutter 502 in position within the pipe 600. The opening of the valve 1000 is carried out by imparting an inverse torque to the coupling device 1. A bottom effect in the pipe 600 or any other event which would apply to the shutter 502 a translation force along the axis A towards the other end of the valve 1000, namely the actuator 100, would be transmitted by the rod 501, the mechanical connection 50, the output shaft 302, the conversion means 300 and the output shaft 301 but would not cause movement thanks to the locking system 20 of the shaft 2 of the bidirectional backstop device 200.

[0044] Compared to prior art valves using threaded rod and trapezoidal thread nut assemblies, the kinematic chain proposed here offers a much higher efficiency, estimated at 85% to 90%, by allowing the use of means 300 for converting a translational movement into a rotational movement such as a satellite roller screw. This type of means in fact offers a significant reduction in friction. The irreversibility of the movement is ensured by the bidirectional anti-backoff device 200, which prevents any rotation of the shaft 2 which would not result from the torque imposed by the actuator 100 and transmitted by the coupling device 1. In addition, the reduction in friction reduces wear and therefore increases the overall service life of the kinematic chain, and consequently of the valve 1000.

[0045] In an alternative embodiment, a damper 400 has the function of reducing the increase in torque that the actuator 100 must provide when the shutter 502 comes to a stop in its closing position, at the end of a closing movement of the valve 1000. The damper 400 is placed for example vertically at least part of the input shaft 301. The damper 400 may for example comprise one or more compressible elastic washers 401. In the embodiment of [Fig. 4], the elastic washers 401 thus oppose the raising of the nut of the satellite roller screw, raising caused by the end of travel of the assembly formed by the rod 501 and the shutter 502. The damper 400 therefore allows improved overall maneuverability of the valve 1000.

[0046] In another alternative embodiment, the means 300 for converting the translational movement into rotational movement can be integrated directly inside the bidirectional anti-backoff device 200. For example, the shaft 2 can be the nut of a satellite roller screw, so that the torque imposed by the actuator 100 and transmitted by the coupling device 1 sets the nut in rotation, which causes the translation of the screw passing through the bidirectional anti-backoff device 200. The valve 1000 provided with such a device for irreversibly converting a rotational movement into translational movement 2000 has the advantage of being much more compact while offering the same functions.

[0047] The combination of the proposed bidirectional anti-backoff device 200 and a means 300 for converting a rotational movement into a translational movement forms a device for irreversibly converting a rotational movement into a translational movement 2000, which can be mounted independently on many types of existing mechanical members, for example a valve 1000 with a translational stem like that described here.

[0048] However, the bidirectional backstop device 200 described herein may also be mounted, independently of a conversion means 300 or any other element described herein, on any type of mechanical devices. For example, the bidirectional backstop device 200 may be integrated into a rotating stem valve, which does not require conversion of the torque of an actuator into a translational movement.

[0049] The invention makes it possible, thanks to the better efficiencies offered, to reduce the power required for the actuators and to improve the maneuverability of the valve. Maintenance can be carried out on the actuator 100 while leaving the valve 1000 mounted on the pipe 600. The reduction in the power required to be supplied by the actuator 100 allows the reduction of the size thereof, and therefore a reduction in the overall weight of the valve 1000. The reduction in weight also allows for better resistance under earthquakes.

Claims

Claims

1. Bidirectional anti-backoff device (200) adapted to transmit a rotational torque from an actuator (100) to a shaft (2) comprising: - a casing (0) arranged around a shaft (2), adapted to be in rotation around an axis (A) of rotation and movable in rotation relative to the casing (0); - a key (3) extending radially projecting from the shaft (2); - a rotation drive system (10) for the shaft (2) arranged inside the casing (0), the rotation drive system (10) comprising: - a coupling device (1) with the actuator (100) comprising a central opening (11) in which the shaft (2) and the key (3) are inserted, allowing an angular clearance (12) between the walls of the central opening (11) and the key (3); - a ring (6), arranged opposite and at a distance from the coupling device (1), the ring (6) comprising a central opening (61) in which the shaft (2) and the key (3) are inserted, allowing angular play (62) between the walls of the opening and the key (3); - a spacer (7), arranged between the coupling device (1) and the ring (6), comprising a central opening (71) in which the shaft (2) and the key (3) are inserted; - several rods (8) extending from the coupling element (1) to the ring (6) passing through the spacer (7), so as to secure them in rotation; - a locking system (20) for the shaft (2) arranged inside the casing (0), the locking system (20) for the shaft (2) comprising: - a cam (4) arranged around the shaft (2) and comprising a housing receiving the key (3), the cam (4) being capable of being driven by the key (3); - several rollers (5) arranged circumferentially around the shaft (2) between the rods (8), the rollers (5) extending from the coupling device (1) towards the ring (6) passing through the spacer (7) so as to allow circumferential play- differential (13) at the coupling device (1), a circumferential clearance (73) at the spacer (7) and a circumferential clearance (63) at the ring (6); - several compression springs (9) arranged around the shaft (2), each spring (9) comprising a compression axis perpendicular to the axis (C) of each roller (5), the springs (9) being fixed in the coupling device (1) and in the ring (6), the springs (9) being adapted to keep the rollers (5) in contact with the cam (4), when they are at rest, at a rate of two springs per roller (5);the bidirectional anti-backoff device (200) being such that when the shaft (2) receives a torque from a member other than the rotational drive system (10) of the shaft (2), the cam (4) wedges one roller (5) out of two in abutment against the casing (0), thus blocking any rotational movement of the shaft (2), while a torque applied to the rotational drive system (10) successively causes, thanks to the circumferential clearances (13) and (63), the separation of one roller (5) out of two, in order to free the cam (4) from contact with the rollers (5), then the rotational drive by the angular clearances (12) and (62) of the key (3), and therefore the rotation of the shaft (2) relative to the casing (0).;

2. Device for irreversibly converting a rotational movement into a translational movement (2000), comprising a bidirectional anti-backoff device (200) according to claim 1, in which the shaft (2) is a nut of a satellite roller screw.

3. Device for irreversibly converting a rotational movement into a translational movement (2000) comprising: - a bidirectional anti-backoff device (200) adapted to drive a shaft (2) in rotation according to claim 1; - a conversion means (300) configured to convert a rotational movement into a translational movement, the input shaft (301) of the conversion device being driven directly or indirectly by the shaft (2).

4. Device for irreversibly converting a rotational movement into a translational movement (2000) according to claim 3, in which the conversion means (300) is a satellite roller screw or a ball screw.

5. Device for irreversibly converting a rotational movement into a translational movement (2000) according to any one of claims 3 to 4, the device comprising a damper (400) configured to oppose the raising of the conversion means (300) when the output shaft (302) of the conversion means (300) is at the end of its travel.

6. Device for irreversibly converting a rotational movement into a translational movement (2000) according to claim 5, in which the damper (400) comprises an elastic washer (401).

7. Assembly comprising a tap (1000), the tap (1000) comprising a rod (501) and a shutter (502), configured so that the rod (501) is driven in translation by the device for irreversibly converting a rotational movement into a translational movement (2000) according to one of claims 2 to 6, so as to place the shutter (502) in a stable position.

8. An assembly according to claim 7, further comprising a mechanical connection (50), the mechanical connection (50) being configured to prevent the transmission of a rotational movement by the rod (501) to the device according to one of claims 2 to 6.

9. An assembly according to claim 8, wherein the mechanical connection (50) is a ball joint with a finger (51), the finger being optionally configured to indicate the position of the stem (501) of the tap (1000).

10. Assembly according to claim 8, in which the mechanical connection (50) is a non-sliding pivot connection on the axis (A).

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