EP3698062A1

EP3698062A1 - Spherical device provided with convex splines for forming a ball-and-socket joint having a finger, and wobble pump provided with such a device

Info

Publication number: EP3698062A1
Application number: EP18785580.4A
Authority: EP
Inventors: Jean Tricard; Julien TROST; Philippe Pagnier
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2017-10-20
Filing date: 2018-10-08
Publication date: 2020-08-26
Also published as: CN111212985A; US20210079955A1; FR3072739A1; FR3072739B1; CA3078596A1; WO2019076672A1

Abstract

The present invention concerns a device for forming a ball-and-socket joint having a finger. The device (10) comprises a cylindrical inner surface (11). The device comprises an outer surface (12) in the form of a sphere truncated at the ends of same. According to the invention, the inner surface (11) comprises at least one groove (14) or one spline. Moreover, the outer surface (12) comprises at least one convex spline (13). The invention also concerns a connection between a shaft and a plate with such a device, and a wobble pump equipped with such a device.

Description

The present invention relates to the field of finger ball joint connections, in particular for use in a barrel pump. .

A finger ball joint (also called spherical finger connection) is a connection between two mechanical elements, which has four degrees of connection and two degrees of relative movement; only two relative rotations are possible, the three translations and the last rotation being linked. In general, it is a ball with a finger impeding rotation. The operating principle of this type of connection is to ensure the transmission of torque between two rotating assemblies whose axes are not collinear. For example, in the case of a barrel pump, it may be a connection between the drive shaft and the turntable.

Today, there are two main types of spherical finger connections:

• The universal joints (figure 1) allow very strong torque transmissions but with a relatively low angular movement (around 20 degrees). They are also relatively bulky. The universal joint is the most used finger joint mechanism in mechanical systems, for example in the automotive field. Figure 1 illustrates an example of a double universal joint in two distinct positions. The universal joint comprises two sleeves 1 and 3 at its ends, and a shaft 2 arranged between the sleeves 1 and 3. A hinge 4 is assembled between the sleeve 1 and the shaft 2. In the same way, a hinge 5 is assembled between the shaft 2 and the sleeve 3. Each joint 4 and 5 comprises two forks and a spider (not shown), to allow the relative movements of the parts. The angular deflection a is low of the order of 20 °.

• Ball joints (Figure 2) are very compact and offer angular deflection exceeding 50 degrees. However, transmissible torques are lower than for universal joints, and in addition, their assembly and their implementation (lubrication for example) are relatively complex. Figure 2 illustrates an example of a ball joint. The ball-and-socket joint allows the connection between a shaft 6 and a shaft 8. The ball-and-socket joint comprises a substantially spherical raceway 7, in which balls 9 circulate. Patent application WO 2017051710 also discloses a finger-ball joint having an interesting angular amplitude. However, the complexity of the mechanism is important, and the transmittable torque relatively low. Furthermore, there are other examples of this type of connection for applications with low rotational speed and low torque, and which are not suitable for high torques and / or high speeds.

To overcome these drawbacks, the present invention relates to a device for forming a finger joint connection. The device includes a cylindrical inner surface for mounting on a shaft. The device has an outer surface having a truncated sphere shape at its ends. According to the invention, the inner surface has at least one groove or groove for inserting a key to transmit the torque between a shaft and the device. In addition, the outer surface has at least one domed groove to transmit the torque between the device and a component, including a tray or disk. This specific shape (spherical with at least one groove) provides the finger joint connection, and allows the transmission of high torque, as well as a large angular movement. The device according to the invention

The invention relates to a device for forming a finger-ball joint connection in the form of a hollow revolution piece comprising a substantially cylindrical inner surface and an outer surface having substantially the shape of a truncated sphere at its two ends. Said inner surface comprises at least one groove, and in that said outer surface comprises at least one curved groove.

According to one embodiment, said outer surface comprises a plurality of curved splines regularly distributed.

Advantageously, said outer surface comprises between five and nineteen curved flutes, preferably between seven and thirteen curved flutes.

According to one embodiment, said curved grooves have a substantially square, rectangular or trapezoidal section.

In one aspect, said device is formed of a one-piece piece.

According to one characteristic, said device is made of metal, in particular of ferrous alloy, preferably of steel. Advantageously, according to an axial sectional plane of said device, the angle β formed by two ends of said outer surface of said device and the center of said sphere is between 60 and 120 °, in particular between 80 and 100 °, and preferably the angle β is substantially 90 °.

In addition, the invention relates to a connection between a shaft and a tray. A device for forming a finger ball joint according to one of the preceding features is mounted on said shaft by means of at least one key or splined shaft, and said plate is mounted on said outer surface of said device to form a finger ball joint connection by means of at least one groove cooperating with said at least one curved groove.

Advantageously, said plate comprises at least one means forming an angular stop.

In addition, the invention relates to a barrel pump with turntable comprising a connection according to one of the preceding characteristics for the connection between a drive shaft and said turntable.

The invention also relates to a use of said barrel pump according to one of the preceding features, for a drilling operation, in particular for the injection of a drilling mud.

Brief presentation of the figures

Other features and advantages of the device according to the invention will appear on reading the following description of nonlimiting examples of embodiments, with reference to the appended figures and described below.

Figure 1, already described, illustrates a universal joint according to the prior art.

Figure 2, already described, illustrates a ball joint according to the prior art.

FIG. 3 illustrates a device for forming a finger-joint connection according to one embodiment of the invention.

FIG. 4 illustrates a sectional view of a device for forming a finger-joint connection according to one embodiment of the invention.

FIG. 5 illustrates a finger-to-finger connection between a shaft and a plate according to one embodiment of the invention. Detailed description of the invention

The present invention relates to a device for forming a finger joint connection. A finger-jointed connection is a connection between two mechanical elements, which has four degrees of connection and two degrees of relative movement; only two relative rotations are possible, the three translations and the last rotation being linked. In general, it is a ball with a finger impeding rotation. The operating principle of this type of connection is to ensure the transmission of torque between two rotating assemblies whose axes are not collinear.

For the sake of clarity of the description, the term device is used in the following description to designate the device to form a finger joint connection.

According to the invention, the device for forming the finger ball is a piece of hollow revolution. We recall that in geometry, a piece of revolution is a piece generated by a closed flat surface rotating around an axis located in the same plane as it and not having in common with it any point or only points on its border .

The device for forming the finger ball comprises a substantially cylindrical inner surface. Thus, the hollow of the device is substantially cylindrical. In this way, the device is adapted to be mounted on a cylindrical shaft. The inner surface includes at least one groove for insertion of a key or splined shaft (in the case of a plurality of splines), for the purpose of transmitting the torque between a shaft and the device. The use of a transmission key or splines allows the transmission of significant torque.

The device according to the invention comprises an outer surface having substantially the shape of a truncated sphere at its ends. The sphere is truncated by two planes perpendicular to the axis of revolution of the device. This partially spherical shape of the outer surface allows a ball joint connection. In addition, the outer surface has at least one curved groove. The convex groove makes it possible on the one hand to form the finger of the finger ball joint, and on the other hand allows the transmission of significant torque between the device and an element positioned on the external surface of the device (for example a plate or a disk).

This design of the device to form a finger joint connection allows high compactness, large angular movement, and ease of implementation.

Advantageously, the groove and the groove or grooves are parallel to the axis of revolution of the device. Preferably, the groove or grooves have a curved shape parallel to the generally spherical shape of the outer surface of the device. Thus, it can be involute splines in order to have the largest transmissible torque. According to one aspect of the invention, the outer surface has a plurality of curved splines regularly distributed over the circumference of the spherical surface. In this way, a larger torque can be transmitted between the device according to the invention, and the element positioned on the outer surface of the device. The grooves are preferably parallel to each other. For example, the outer surface of the device may comprise between five and nineteen corrugated grooves, preferably between seven and thirteen, in order to optimize the manufacturing and the torque transmissible by the device, as well as to optimize the distribution of forces in the fluting.

In order to have good mechanical strength of the curved splines, the grooves may have a substantially rectangular section, substantially square or substantially trapezoidal. Flutes may have fillet radii to avoid stress concentrations.

Advantageously, the device according to the invention may be symmetrical with respect to a plane perpendicular to its axis of revolution. Thus, the device is simple to manufacture.

According to one characteristic of the invention, the groove may have a substantially rectangular section. In this way, it is possible to use, in an easy manner, a substantially parallelepipedal key to transmit the torque.

In order to simplify the assembly and manufacture of the device according to the invention, the device may consist of a single piece.

Advantageously, the device according to the invention can be made of metal, in particular of ferrous metal alloy, for example steel, in order to have sufficient strength to transmit high torques.

The device according to the invention can be obtained by machining, molding, additive manufacturing, or any similar method.

According to a nonlimiting embodiment, the device according to the invention may have at least one of the following dimensions: the ratio of the diameter of the sphere to the length of the device along the axis of revolution may be between 1 and 2, preferably between 1.4 and 1.6, and may be for example 1.45,

the sections of the groove and the key can depend on the diameter of the internal surface and the torque to be transmitted,

the section of the curved grooves may have dimensions of between 300 and 1000 mm ² and more specifically between 500 and 700 mm ² .

Figure 3 illustrates, schematically and in a nonlimiting manner, a device for forming a finger-joint connection according to one embodiment of the invention. The device 10 is a piece of revolution about the axis XX. The device 10 is hollow, and has a cylindrical inner surface 1 1. The inner surface 1 1 has a groove 14. The section of the groove 14 is substantially rectangular. The device 10 comprises an outer surface 12 having the shape of substantially a truncated sphere at its two ends, the truncation being carried out at two planes perpendicular to the axis XX. The outer surface 12 has a plurality of curved splines 13, in the case shown nine curved splines 13. The curved splines 13 have an outer surface substantially parallel to the outer surface 12 of the device. It is about 13 involute flutes of circle.

According to one embodiment of the invention, according to an axial sectional plane of said device (plane comprising the axis of revolution), the angle β formed by two ends of the outer surface of the device according to the invention and the center the sphere (corresponding to the outer surface) may be between 60 ° and 120 °, more specifically between 80 ° and 100 °, and preferably is substantially 90 °. This angle ensures a large patella surface, and therefore allows a large angular deflection, for example of the order of 40 °.

FIG. 4 illustrates, schematically and in a nonlimiting manner, the assembly of a shaft 15 with a device 10 to form a finger-joint connection according to one embodiment of the invention. Figure 4 is a sectional view along an axial sectional plane (plane comprising the axis of revolution XX) of this assembly. In this figure, only a curved groove 13 is shown. The shaft 15 is mounted in the device 10 by means of a key 17. In this figure, the point E1 corresponds to a first end of the outer surface 12 of the device 10, the point E2 corresponds to a second end (opposite to the first end) of the outer surface 12 of the device 10, and the point O corresponds to the center of the sphere of the outer surface 12. The angle β formed by the points E1, O and E2 is substantially 90 °. In addition, the invention relates to a connection between a tree and a plate (or disk) for example. This connection is a finger-joint connection. The connection is implemented by the device to form a finger-joint connection according to any combination of features described above. Thus, for this connection, the device for forming a finger ball is mounted on the shaft by means of at least one key. In addition, the plate is mounted on the outer surface of the device to form a connection finger ball joint by means of at least one curved groove cooperating with the curved groove or grooves.

Thanks to the invention, a finger ball joint is formed between the shaft and the plate: the plate can rotate by means of the spherical outer surface of the device, and the torque can be transmitted from the shaft to the plate by the key and by the curved groove or grooves.

This is a spherical connection finger constant speed without slip. This means that the rotation speed at the input of the link is identical to the rotational speed at the output of the link, and that this connection is done without slip but by a direct mechanical drive.

This design of the connection allows a finger-to-finger connection having a high compactness, a large angular displacement, and a simplicity of implementation. To achieve the finger joint connection, the plate may comprise a substantially spherical inner surface.

In order to facilitate the assembly of the connection, the plate may consist of two half-shells. Alternatively, the tray can be made in one piece.

According to one aspect of the invention, the plate (or disk) may comprise means forming an angular stop. It may be a surface coming into contact with the shaft, for example, the plate may comprise a conical inner surface coming into contact with the shaft for the maximum deflection angle.

Figure 5 illustrates, schematically and in a nonlimiting manner, the connection of a shaft 15 to a plate 16 by means of the device 10 to form a finger joint connection as defined above. The device 10 shown corresponds to the embodiment of Figure 3. The shaft 15 is mounted in the device 10 by means of a key 17. In addition, the plate 16 is mounted on the device 10 by means of grooves (grooves females) cooperating with the curved grooves 13 of the outer surface of the device 10. In addition, the invention relates to a barrel pump with a turntable comprising a connection as defined above, between a drive shaft and the turntable.

The purpose of the barrel pump is to pump a fluid (eg water, oil, gas, drilling muds, etc.) by means of a linear displacement of several pistons. This type of pump has the advantage of being compact, having interesting mechanical and volumetric efficiencies, an excellent weight / power ratio. In addition, barrel pumps with a turntable are suitable for high pressure pumping.

The barrel pump according to the invention comprises a housing and comprises within a housing:

- A drive shaft: it is driven in rotation, relative to the housing by an external energy source, including a driving machine (for example thermal or electrical), in particular by means of a transmission (for example a gearbox),

a rotary plate driven by the drive shaft: the turntable is inclined with respect to the drive shaft; the inclination of the turntable generates an oscillation movement of the turntable; the turntable has a rotational movement and an oscillation movement with respect to the housing,

a cylinder block (called a barrel), comprising at least two compression chambers (also called jackets) distributed circumferentially (in other words the compression chambers are distributed in a circle), and

- At least two pistons in translation respectively in the compression chambers, the pistons are driven by the rotary plate by means of rods (the rods connect, by means of ball joints, the turntable and the pistons so as to transform the movement of the piston. oscillation in translational movement of the pistons), and the translation of the pistons within the compression chambers realize the pumping of the fluid.

According to the invention, the rotary plate is driven by the drive shaft by means of a finger ball joint according to the invention, the position of the finger ball joint determining the inclination of the rotary plate relative to the shaft. drive. For the invention, the finger of the ball joint allows the adjustment of the inclination of the plates relative to the drive shaft. Indeed, the pump comprises means for controlling the finger ball, and thus the inclination of the turntable relative to the drive shaft.

Thus, the inclination of the turntable is continuously adjustable, which allows a variable displacement. Indeed, the inclination of the plate affects the stroke of the pistons. In addition, the pump according to the invention allows good flexibility thanks to the continuous variation of the unit cubic capacity. In addition, the pump according to the invention allows a good reliability thanks to the possibility of progressive operation of the pump: for example, during start-up, the angle of inclination may be low, and subsequently, it may be increased depending on the desired conditions (flow and fluid pressure). This reliability can not be obtained with a pump whose inclination of the plate is fixed, or for which the inclination can not vary continuously.

The tray may be substantially disk-shaped. However, the tray can have any shape. Only the compression chambers (and the pistons) are distributed on a circle.

Advantageously, the pump according to the invention may comprise a number of pistons of between three and fifteen, preferably between five and eleven. Thus, a large number of pistons provides a continuous flow upstream and downstream of the pump.

In a conventional manner, the pump further comprises an inlet and an outlet of the fluid to be pumped. The fluid passes through the inlet of the pump, enters a compression chamber, is compressed, and is discharged from the pump through the outlet by means of the piston.

In addition, conventionally, the pivot links are formed by bearings or bearings, favoring the relative movement of the elements.

Preferably, the cylinder block (or barrel) can be fixed relative to the housing. Thus, the supply of energy to perform the pumping is performed at the drive shaft only, by the rotation thereof; the number of rotating parts is thus restricted.

Alternatively, the cylinder block can also be rotatable relative to the housing.

The advantage of this architecture is that it can easily make the adjustable tray tilt and thus have the possibility of variable displacement.

The invention also relates to the use of the pump according to the invention for a drilling operation, in particular for the injection of drilling muds into a wellbore. Indeed, the pump according to the invention is well suited to this use, for its flexibility, compactness, and resistance to high pressures.

For example, the pump according to the invention can be sized to operate up to pressures of the order of 1500 bars, that is to say 150 MPa. In addition, the pump according to the invention can be sized to operate at flow rates ranging from 30 to 600 m ³ / h.

Claims

claims

1) Apparatus for forming a finger-shaped spherical link in the form of a hollow revolution piece comprising a substantially cylindrical inner surface (1 1) and an outer surface (12) having substantially the shape of a truncated sphere at its two ends, characterized in that said inner surface (1 1) comprises at least one groove (14) or at least one groove, and in that said outer surface (12) comprises at least one curved groove (13).

2) Device according to claim 1, wherein said outer surface (12) comprises a plurality of regularly distributed curved splines (13).

3) Device according to claim 2, wherein said outer surface (12) comprises between five and nineteen curved grooves (13), preferably between seven and thirteen convex flutes (13).

4) Device according to one of the preceding claims, wherein said curved grooves (13) have a substantially square, rectangular or trapezoidal section.

5) Device according to one of the preceding claims, wherein said device (10) is formed of a single piece.

6) Device according to one of the preceding claims, wherein said device (10) is metal, especially ferrous alloy, preferably steel. 7) Device according to one of the preceding claims, wherein in an axial sectional plane of said device (10), the angle β formed by two ends of said outer surface (12) of said device (10) and the center (O ) of said sphere is between 60 and 120 °, in particular between 80 and 100 °, and preferably the angle β is substantially 90 °. 8) Connection between a shaft (15) and a plate (16), characterized in that a device (10) for forming a finger ball joint connection according to one of the preceding claims is mounted on said shaft (15) by means of at least one key (17) or a splined shaft, and in that said plate (16) is mounted on said outer surface (12) of said device (10) to form a finger-jointed connection by means of at least one groove cooperating with said at least one curved groove (13). 9) Connection according to claim 8, wherein said plate comprises at least one means forming an angular stop.

10) A barrel pump with turntable comprising a connection according to one of claims 8 or 9 for the connection between a drive shaft (15) and said turntable (16).

1 1) Use of said pump barrel according to claim 10 for a drilling operation, in particular for the injection of a drilling mud.