WO2002063175A2

WO2002063175A2 - Articulated joint for transmitting motion between two shafts

Info

Publication number: WO2002063175A2
Application number: PCT/EP2002/001150
Authority: WO
Inventors: Giuseppe Banfi
Original assignee: Giuseppe Banfi
Priority date: 2001-02-06
Filing date: 2002-02-05
Publication date: 2002-08-15
Also published as: EP1373747A2; WO2002063175A3; ITMI20010231A1

Abstract

An articulated joint (1) for transmitting motion between two shafts has a hub (2) rigidly associated with the end of a first shaft, and an outer body (104) rigidly associated with the end of a second shaft. Radial interference members (3) are arranged between the hub and the outer body, the members being adapted to rotate with respect to their own radial axis and to perform a translational motion with respect to a longitudinal direction and to rotationally rigidly couple the outer body and the hub, in order to allow the transmission of motion between the shafts even when their respective rotation axes are not coaxial.

Description

ARTICULATED JOINT FOR TRANSMITTING MOTION BETWEEN TWO SHAFTS

The present invention relates to an articulated joint for transmitting motion between two shafts. Articulated joints allow mechanical connection, for motion transmission, between non-coaxial shafts. In particular, articulated joints allow to transmit motion between shafts whose axes are parallel but do not coincide or whose axes are not parallel but incident.

With an appropriate combination of articulated joints, it is also possible to transmit motion between shafts whose axes are neither parallel nor incident.

One type of articulated joint that is widely used in all heavy-duty applications, such as steam turbine shafts, propeller shafts, mills, et cetera, is the toothed joint, in which the hubs, supported by the two shafts, are provided with peripheral sets of teeth in which the corresponding internal sets of teeth of the cup that connects the two hubs engage.

The sets of teeth can have slotted or barrel-like profiles, so as to allow angles of 2- 3° between the shafts.

Toothed joints have great load-bearing capacities, but they are affected by drawbacks, including the need for careful maintenance, especially as regards internal lubrication.

Another disadvantage of toothed joints is due to the relatively small angle allowed between the two shafts.

The aim of the present invention is to provide an articulated joint that is improved with respect to the joints of the cited prior art. An important object of the present invention is to provide a joint that allows effective transmission of motion even when the angle between the shafts is relatively large.

Another object of the present invention is to provide a joint that is durable and highly reliable. Another object of the present invention is to provide a joint that does not require complicated and demanding maintenance.

Another object is to provide an articulated joint that can be manufactured with competitive production costs.

This aim, these objects and others that will become better apparent hereinafter are achieved by an articulated joint for transmitting motion between two shafts, as claimed in the appended claims.

Further characteristics and advantages of the present invention will become better apparent from the description of preferred but not exclusive embodiments thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is an exploded perspective view of a joint according to the invention; Figure 2 is a partial and partially sectional side view of a joint according to the invention;

Figure 3 is a view of a typical application of the joint according to the invention; Figure 4 is a partially sectional side view of two coupled joints connecting aligned shafts, according to the invention;

Figure 5 is a view, similar to Figure 4, of two coupled joints connecting non-aligned shafts, according to the invention;

Figure 6 is a partially sectional side elevation view of a further embodiment of the articulated joint according to the invention;

Figure 7 is an enlarged-scale view of the articulated joint of Figure 6; Figure 8 is a partially sectional side view of a further embodiment of the articulated joint according to the invention;

Figure 9 is a partially sectional side view of a further embodiment of the articulated joint according to the invention;

Figure 10 is a partially sectional side view of a further embodiment of the articulated joint according to the invention;

Figure 11 is a sectional side view of a further embodiment of the articulated joint according to the invention; Figure 12 is a sectional side view of the articulated joint according to an aspect of the invention.

With reference to the above cited -figures, the articulated joint, according to an embodiment of the invention, generally designated by the reference numeral 1, comprises a hub 2, which can be rigidly associated with the end of a first shaft 102 having a rotation axis 103, and an outer body 104, which can be rigidly associated with the end of a second shaft 105 having a rotation axis 106.

The hub 2 is constituted by a portion of a sphere and has an axial hole for fixing to the end of the first shaft 102.

The outer body 104 comprises a ring 4, which is rotationally rigidly coupled to the hub 2 by means of interference members constituted, in this example, by detents or pins 3 which are arranged radially.

The outer surface 5 of the hub 2 has cylindrical seats 6. Each seat accommodates a cylindrical portion 7 of each detent 3 so that the detent can rotate, about a radial axis, with respect to the hub 2. Each detent 3 also has a prism-shaped portion, preferably having beveled ends, so as to form a tooth 8. The prism-shaped portions 8 of the detents 3 engage respective slots 10 formed longitudinally on the internal surface 9 of the ring 4.

Each slot 10 allows the respective tooth 8 of the detent 3 to slide along a longitudinal axis 133 which is parallel to the rotation axis of the ring 4 and therefore of the outer body 104.

The outer body 104 also comprises a first flanged body 11 and a second flanged body 12, which retain the ring 4 between them and are shaped so as to form a seat that is complementary to the hemispherical shape of the hub 2.

Each flanged body 11 and 12 comprises a gasket 13 of the O-ring type in order to provide a seal between the hub and the outer body, so as to retain lubricant internally.

As shown more clearly in Figure 2, the joint according to the invention allows an inclination of the rotation axis 103 of the first shaft 102 with respect to the rotation axis

133 of a second shaft that can be connected to the outer body 104. This inclination is allowed by the fact that each detent 3 can rotate, with respect to a radial axis, and at the same time slide longitudinally in the respective slot 10 of the ring 4. Figure 2 illustrates an embodiment of the joint comprising four detents, arranged at 90° to each other in order to better illustrate the operation of the joint according to the invention.

When the axis 103 of the hub 2 is inclined with respect to the axis 133 of the outer body 104, the upper and lower detents 3, with reference to the figure, are shifted with respect to a position that is centered in the respective slot. At the same time, the _, detents arranged at 90° to the upper and lower detents, only one of which is shown in Figure 2, rotate about an axis that is radial with respect to the hub, since the respective slot is rotated, with respect to the rotation axis 103 of the hub, through an angle that corresponds to the angle between the rotation axis 103 of the first shaft and the rotation axis 133 of the second shaft, not shown, which is rigidly coupled to the outer body 104.

In practical applications, the joint 1 according to the invention is generally in the form of a double joint 101, as shown in Figures 4 and 5, and comprises two outer bodies 104 with respective hubs 2 which are associated with respective shafts 102 and 105. The outer bodies 104 are mutually associated by means of fixing members such as bolts 14.

Figures 4 and 5 also illustrate the joint with four detents for each hub but, as will be apparent to the person skilled in the art, the number of detents can vary according to requirements. For example, the hub illustrated in Fig. 1 is provided with six detents.

It should also be noted that the radial rotation of each detent can be achieved by means of seats that rotate in the ring 4, which instead of being provided with slots 10, as in the illustrated examples, can be provided with cylindrical seats for intermediate cylindrical members, which are in turn slotted in order to accommodate teeth which are rigidly coupled to the hub.

Figure 3 schematically illustrates an example of practical application of the joint according to the invention, in which two pairs of joints 101 are mutually connected by means of an auxiliary shaft 15 and are connected respectively to a motor shaft 16 of a machine 17 and to a shaft 18 of a user device 19. In this configuration, the transmission of motion is ensured even when the axes of the shafts 16 and 18 are neither parallel nor incident.

Another embodiment of an articulated joint according to the invention is shown in Figure 6, and in enlarged scale in Figure 7; in this embodiment, the outer body 204 accommodates the hub 2 and is formed monolithically. The slots 10, that receive the prism-shaped portions 8 of the detents 3, are formed longitudinally on the inner surface of the outer body.

The outer body 204 comprises a portion 240 that is flanged in order to allow the coupling, by means of fixing members 14, of two outer bodies 204 in order to form a double joint 201. An annular member 241 provides for the axial adjustment of the hub 2 and can slide longitudinally on a threaded portion formed on the inner surface of the outer body 204 at a longitudinal end that is not flanged.

The annular member 241 is shaped complementarily to the outer surface of the hub, and comprises a gasket 13, of the O-ring type, in order to provide a seal between the hub 2 and the outer body 204.

The outer body 204 has a guiding portion for a locking grub screw 242, for preventing mutual sliding between the annular member 241 and the outer body 204 during operation.

Figure 8 illustrates a further embodiment of the articulated joint according to the invention, wherein two outer bodies 204 are associated by means of a sleeve 350 which is flanged at its longitudinal ends, each end being coupled, by means of fixing members 14, to the flanged portions 240 of the respective outer bodies 204 in order to form a double joint 301.

Figure 9 illustrates a further embodiment of the articulated joint according to the invention, particularly for connecting shafts arranged vertically, in which two outer bodies 204 are associated vertically, retaining a safety disk 460 which bears the axial load and has flanges provided with holes in order to receive the fixing members 14 that fastens the two outer bodies 204 through the flanged portions 240 in order to form a double joint 401. Figure 10 illustrates a further embodiment of the articulated joint according to the invention, comprising an outer body 501 that is formed monolithically and accommodates two hubs 2 associated with respective shafts. On the inner surface of the outer body there are longitudinal slots 10, adapted to receive the prism-shaped portions 8 of the detents 3 related to each hub 2. The outer body 501 has two annular members 241 , each of which can slide longitudinally on a threaded portion formed on the inner surface of the outer body 501 at each longitudinal end. The annular members 241 provide for the axial adjustment of each hub 2. The annular members 241 are shaped complementarily to the outer surface of the hub 2 and comprise a gasket of the O-ring type in order to provide a seal between the hub and the outer body. Locking grub screws 242 prevent mutual sliding between each annular member 241 and the outer body 501 during operation.

Figure 11 illustrates a further embodiment of the joint according to the invention, which is constituted by a double joint 601 comprising an outer body 604 accommodating two hubs 670 associated with the respective shafts. The outer body can be constituted, according to requirements, either by a single sleeve 671 or by two flanged rings 672 which are identical and are associated by means of fixing members 14, their overall dimensions being equivalent to those of the sleeve 671. In both cases, the outer body 604 comprises slots 10, formed on the inner surface, and adapted to receive the prism-shaped portions 8 of the detents, accommodated in the cylindrical seats provided on the outer surface of the hubs 670.

The joint 601 is completed by two annular members 673, that provide for the axial adjustment of each hub 670 and are screwed onto threaded portions formed on the outer surface of the outer body 604, at its longitudinal ends. . The portion of the annular member that is in contact with the hub 670 is shaped complementarily to a convex annular protrusion 674, which is formed by the outer surface of the hub and is adapted to guide the inclination of the hub on the annular member.

The annular member also comprises a gasket 613 of the O-ring type, in order to provide a seal between the hub 670 and the outer body 604. Figure 12 illustrates a particularly preferred embodiment of a double joint 701 , according to the invention, comprising an outer body 704 adapted to accommodate two hubs 770 associated with the respective shafts.

The outer body comprises two sleeves 672, that can be identical, and are associated by means of fasteners, in the form of screws 14. The outer body 704 comprises slots 10, formed on the inner surface, and adapted to receive the prism-shaped portions 8 of the detents accommodated in the cylindrical seats, provided on the outer surface of the hubs 770.

The joint 701 is completed by two annular members 773 that provide for the axial adjustment of each hub 770 and are screwed, by means of screws 714, onto threaded portions formed on the outer surface of the outer body 704, at its longitudinal ends.

The annular members are provided with a seal member 713, in the form of an annular seal accommodated in an annular seat formed between the outer wall of the annular member 773 and a ring 715. The seal member 713 moves in the annular seat in order to maintain a seal between the hub 770 and the outer body 704, whatever is the angular position of the hub 770 with respect to the outer body 704.

In practice it has been seen that the invention achieves the intended aim and objects, an articulated joint having been provided which is capable of coupling non- coaxial shafts while ensuring effective motion transmission.

An advantage of the joint according to the present invention is that it requires substantially less maintenance than conventional joints having an equal performance, especially as regards lubrication.

The joint according to the invention is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent elements. The materials used, as well as the dimensions, may be any according to requirements and to the state of the art.

Claims

CLAIMS 1. An articulated joint for transmitting motion between two shafts, comprising a hub to be associated with the end of a first shaft, and an outer body, to be associated with the end of a second shaft, characterized in that it comprises radial interference members between said hub and said outer body, said members being adapted to rotate and perform a translational motion with respect to said outer body and said hub and to rotationally couple said outer body and said hub, in order to allow the transmission of motion between said shafts even when their respective rotation axes are not coaxial.

2. The joint according to claim 1 , characterized in that said hub is constituted by a portion of a sphere and has an axial hole for fixing to the end of the first shaft, said outer body comprising a ring which is rigidly rotationally coupled to the hub by means of said interference members, which are constituted by detents or pins which are arranged radially with respect to the rotation axis of said hub.

3. The joint according to claim 1 or 2, characterized in that the outer surface of the hub has cylindrical seats, each seat accommodating a cylindrical portion of each detent, so that the detent can rotate about a radial axis with respect to the hub; each detent comprising a prism-shaped portion with beveled ends which forms a tooth, said prism-shaped portion of each detent engaging a respective slot of a plurality of slots formed longitudinally on the inner surface of the ring, each slot allowing the respective tooth of the detent to slide along a longitudinal axis that is parallel to the rotation axis of the ring and therefore of the outer body.

4. The joint according to claim 1 or 2, characterized in that the inner surface of said ring has cylindrical seats, each of said seats accommodating a cylindrical portion of an intermediate body which is adapted to rotate with respect to the ring about a radial axis; each intermediate body comprising a slot which is suitable to accommodate a prism-shaped portion, with beveled ends, which forms a tooth and is rigidly associated with the outer surface of said hub; each slot allowing the respective tooth to slide along a longitudinal axis that is parallel to the rotation axis of the ring and therefore of the outer body.

5. The joint according to one or more of the preceding claims, characterized in that said outer body comprises a first flanged body and a second flanged body, adapted to retain the ring between them and shaped so as to form a seat that is complementary to the hemispherical shape of the hub.

6. The joint according to one or more of the preceding claims, characterized in that each flanged body comprises a gasket, of the O-ring type, in order to provide a seal between the hub and the outer body so as to retain lubricant internally.

7. The joint according to one or more of the preceding claims, characterized in that said outer body is formed monolithically and accommodates said hub, said outer body comprising longitudinal slots on its inner surface which are adapted to receive the prism-shaped portions of said detents, said outer body comprising a flanged portion in order to allow coupling, by means of fixing members, between two members of said outer body in order to form a double joint.

8. The joint according to one or more of the preceding claims, characterized in that said outer body comprises an annular member, adapted to provide for the axial adjustment of the hub, said annular member being adapted to slide longitudinally on a threaded portion formed on the inner surface of the outer body at a longitudinal end, said annular member being shaped complementarily to the outer surface of said hub and comprising a gasket of the O-ring type in order to provide a seal between said hub and said outer body, said outer body comprising a guiding portion for a locking grub screw adapted to prevent the mutual sliding of said ring and said outer body during operation.

9. The joint according to one or more of the preceding claims, characterized in that two members of said outer body are associated by means of a tubular member which is flanged at its longitudinal ends, each end being coupled, by means of fastening members, to the flanged portions of said outer bodies.

10. The joint according to one or more of the preceding claims, characterized in that in order to connect shafts arranged vertically, two members of said outer body are associated so as to retain a safety disk which is adapted to bear a vertical axial load and comprises suitable flanges which are provided with holes in order to receive said fastening members to clamp said two outer bodies through flanged portions.

11. The joint according to one or more of the preceding claims, characterized in that it comprises an outer body which is formed monolithically and is adapted to accommodate two hubs associated with respective shafts, said outer body comprising, on its inner surface, longitudinal slots adapted to receive the prism-like portions of said detents related to each one of said hubs, said outer body comprising said annular member at each longitudinal end for the axial adjustment of each hub.

12. The joint according to one or more of the preceding claims, characterized in that it forms a double joint which comprises an outer body adapted to accommodate two hubs associated with the respective shafts, said outer body being constituted by a single sleeve.

13. The joint according to one or more of the preceding claims, characterized in that it forms a double joint which comprises an outer body adapted to accommodate two hubs associated with the respective shafts, said outer body being constituted by two identical flanged rings mutually associated by means of fastening members and whose overall dimensions are equivalent to those of the sleeve.

14. The joint according to one or more of the preceding claims, characterized in that said outer body comprises slots formed on the inner surface and adapted to receive said prism-shaped portions of said detents, accommodated in said cylindrical seats provided on the outer surface of said hubs.

15. The joint according to one or more of the preceding claims, characterized in that it comprises two annular members adapted to provide for the axial adjustment of each of said hubs, said annular members being screwed onto threaded portions formed on the outer surface of said outer body at its longitudinal ends, each of said annular members comprising a portion that is in contact with said hub and is shaped complementarily to a convex annular protrusion that is formed by the outer surface of said hub and is adapted to guide the inclination of said hub on the annular member, said annular member comprising a gasket of the O-ring type in order to provide a seal between said hub and said outer body.

16. The joint according to one or more of the preceding claims, characterized in that said outer body accommodates two hubs to be associated with respective shafts, said outer body comprising two sleeves and further comprising slots, formed on an inner surface of the outer body, and adapted to receive prism-shaped portions of said detents accommodated in said cylindrical seats, provided on the outer surface of said hubs.

17. The joint according to one or more of the preceding claims, characterized in that said sleeves are identical and are associated by means of fasteners, in the form of screws.

18. The joint according to one or more of the preceding claims, characterized in that it comprises two annular members that provide for the axial adjustment of each hub and are screwed onto threaded portions formed on an outer surface of the outer body, at its longitudinal ends.

19. The joint according to one or more of the preceding claims, characterized in that said annular members are provided with a seal member, in the form of an annular seal accommodated in an annular seat formed between the outer wall of the annular member and a ring; said annular seal being adapted to move in the respective annular seat in order to maintain a seal between said hub and said outer body, whatever is the angular position of the hub with respect of the outer body.