WO2002052280A1

WO2002052280A1 - Sensor-holder block and anti-friction bearing comprising a data sensor

Info

Publication number: WO2002052280A1
Application number: PCT/FR2001/004003
Authority: WO
Inventors: François NIARFEIX
Original assignee: Aktiebolaget Skf
Priority date: 2000-12-22
Filing date: 2001-12-14
Publication date: 2002-07-04
Also published as: FR2818708A1; EP1344068A1; FR2818708B1

Abstract

The invention concerns a sensor-holder block (15) designed to be fixed on a ring (1) of a bearing for detecting a rotational parameter of a ring (1) relative to another ring (6). The sensor-holder block (15), annular in shape, comprises a receptacle (22) opening on the outside and provided with electrical connecting means completely arranged in said receptacle (22) and/or in said sensor-holder block (15).

Description

Sensor holder block and rolling bearing with information sensor.

The present invention relates to the field of sensor support blocks and rolling bearings with information sensors used, for example, in electric motors, robots or various rotary members of mechanical assemblies. These information sensor rolling bearings generally have a fixed ring and a rotating ring, one or more rows of rolling elements in contact with raceways arranged on said rings, a sensor assembly secured to the fixed ring and a encoder means secured to the rotating ring and scrolling in rotation in front of the sensor with an air gap. These rolling bearings make it possible to know precisely the angular displacement parameters of a mechanical element: speed, angular position, etc.

Such rolling bearings are known per se, but sometimes have certain drawbacks. Thus, the fixing and / or positioning of the sensor unit on the non-rotating ring of the bearing often requires special machining on said ring, such as a hooking groove having a special suitable profile, or rectified bearing for centering the block. sensor. Such machining prohibits the use of standard rolling bearings for the production of certain dimensions of instrumented rolling bearings with information sensor. Furthermore, the seal between the sensor assembly and the non-rotating ring is not always easily achievable.

Finally, some devices of the prior art have a relatively large size. Document FR-A-2 762 056 describes a rolling bearing with information sensor comprising a fixed ring, a rotating ring, at least one other row of rolling elements arranged between the rings, an encoder means integral with the rotating ring and concentric with it, and a sensor means supported by a block sensor holder secured to the fixed ring and arranged opposite with a small air gap relative to the encoder means, the movement of which during rotation is detected by the sensor means. The sensor holder block is secured to the fixed ring by means of a metal holding member positioned relative to the fixed ring, on a radial face of the latter and welded. A radial or axial opening is provided in the holding member to allow passage to a cable. The cable is securely attached to the sensor unit and the instrumented bearing is delivered as such, fitted with its cable. In the case where the sensor unit is provided with a connector, the latter generally projects with respect to the whole of the sensor unit. In certain applications, where it is desired to have an instrumented bearing, the presence of a sensor unit provided with a wire or a connector projecting from the sensor unit has major drawbacks. The wire and / or the connector interfere with the manual or automatic manipulation of the assembly with a view to mounting the instrumented bearing in the mechanical assembly for which it is intended. The wire and / or connector prevent or complicate automation of the mounting operation and thus significantly increase the cost of this operation.

The invention proposes to remedy the drawbacks of the devices described above.

The invention provides a sensor holder block suitable for automated handling and assembly.

The sensor holder block device, according to one aspect of the invention, is capable of being fixed to a ring of a bearing for the detection of the parameter of rotation of a ring relative to the other ring. The sensor-holder block, of annular shape, comprises at least one cell open to the outside and provided with electrical connection means. The sensor holder block comprises at least one angular indexing means used to achieve an adequate angular positioning of said block with respect to one or more references of the mechanical assembly to which is intended for the instrumented rolling bearing, said indexing means being independent of the cell.

The electrical connection means can be entirely arranged in said cell and / or in said sensor-carrying block. The separate indexing means of the housing allows automatic positioning by a machine during assembly.

The annular shape of the sensor holder block allows mounting around a shaft.

In one embodiment of the invention, the cell is open on an outer circular face of the sensor holder block.

In one embodiment of the invention, the cell is open on an inner circular face of the sensor holder block.

In one embodiment of the invention, the cell is open on a radial face of the sensor holder block situated on the side opposite to a radial face intended to come into contact with said ring.

The rolling bearing, according to one aspect of the invention, comprises a rotating ring, a non-rotating ring, a row of rolling elements disposed between raceways of said rings, an encoder means integral with the rotating ring, and a means sensor comprising a sensor supported by a sensor-holder unit secured to the non-rotating ring and arranged facing and with a small air gap relative to the encoder means, the movement of which during rotation is detected by the sensor. The sensor-holder block, of annular shape, comprises at least one cell open to the outside and provided with electrical connection means. The sensor holder block comprises at least one angular indexing means serving to achieve an adequate angular positioning of said block with respect to one or more references of the mechanical assembly for which the instrumented rolling bearing is intended, said indexing means being independent of the cell. The electrical connection means can be entirely arranged in said cell and / or in said sensor-carrying block.

Advantageously, the sensor holder block has a bore with a diameter greater than that of the inner ring.

Advantageously, the sensor holder block has an outer diameter smaller than that of the outer ring. Advantageously, the sensor holder block has a flat outer front surface.

In one embodiment of the invention, the sensor holder block comprises an annular rib capable of cooperating with a groove in the non-rotating ring.

In one embodiment of the invention, a notch of generally axial shape is provided on the outer surface of the sensor holder block. Said outer surface of the sensor holder block can be cylindrical or radial. The notch can be rounded, V-shaped, symmetrical or asymmetrical. The indexing means may include a notch provided on a radial surface of the block. Said notch may have a rounded section, for example semi-circular, or a general shape of V, symmetrical or asymmetrical with a surface forming a step and a ramp of slight slope. The indexing means provided on the sensor unit but none of which projects from the general cylindrical envelope or from the external face of the unit, do not in any way interfere with the handling and the automated transfer of the parts until final assembly the rolling bearing instrumented in the mechanical member which receives it, for example an electric motor. The indexing means can be used in cooperation with mechanical or optical elements to correctly orient the sensor unit with respect to a reference of an adjacent member and maintain said unit in this position during the mounting of the instrumented bearing in the mechanical member. who receives it. In an electric motor, for example, the indexing means can be used to achieve an adequate angular orientation of the sensor relative to the poles of the stator. The indexing means can also be used in order to correctly orient the connector or the wire with respect to a given reference so that the positioning and routing of the cable can be done at predetermined locations.

Thanks to the invention, it is very easy to automate, both with the manufacturer of instrumented bearings and with the user, the mounting operations. No connection pin projects from the housing. The sensor block and the bearing are in the form of a body of revolution delimited axially by two faces. It’s very easy to handle and automatically circulate such an assembly in feeder chutes of an assembly line. The fact of having a very compact part of revolution, without wire or other projecting element, also facilitates the mounting of the instrumented bearing in the assembly for which it is intended. There is no risk, as can be the case with instrumented bearings provided with protruding wires or connectors, of damaging the wires or connectors during handling.

The present invention will be better understood and other advantages will appear on reading the detailed description of some embodiments taken by way of non-limiting examples and illustrated by the appended drawings, in which:

- Figure 1 is an axial sectional view of a rolling bearing equipped with a sensor block, according to a first embodiment of the invention; - Figure 2 is a view similar to Figure 1, according to a second embodiment of the invention;

- Figure 3 is a front elevation view of the rolling bearing of Figure 2;

- Figures 4 and 5 are variants of Figure 3; - Figure 6 is a perspective view of the rolling bearing of Figure 1;

- Figure J is a perspective view of a variant of Figure 3;

- Figure 8 is a perspective view of a variant of Figure 6;

- Figure 9 is a perspective view of a variant of Figure 7;

- Figure 10 is a front elevation view of the rolling bearing of Figure 9, with partial section; - Figure 1 1 is a detailed view of a variant of Figure 3; and

- Figure 12 is a detailed view of a variant of Figure 3. As can be seen in Figures 1 to 3, the rolling bearing comprises an outer ring 1 comprising a raceway 2 for rolling elements 3 , for example balls, and two lateral radial faces 4 and 5. The rolling bearing also comprises a ring interior 6 provided with a raceway 7 for the rolling elements 3 and two lateral radial faces 8 and 9. The rolling elements 3 are held circumferentially spaced apart by a cage 10. A seal 11 is provided on one of the sides of the rolling bearing and secured to the outer ring 1 by means of a groove 12 disposed axially between the raceway 2 and the side face 5 of said ring.

On the side of the lateral faces 4 and 8 of the outer 1 and inner 6 rings, the rolling bearing is provided with a sensor assembly 13 comprising a sensor 14, for example a Hall effect probe, disposed radially between the bore of the ring outer 1 and the periphery of the inner ring 6, and a sensor block 15 also called sensor body made of synthetic material.

The block 15 has an annular shape with an inner cylindrical surface 16 of diameter greater than the bore of the inner ring 6, an outer cylindrical surface 17 of diameter smaller than that of the outer surface of the outer ring 1, a radial surface 18 in contact with the lateral radial face 4 of the outer ring 1, and a radial surface 19 located on the side opposite to the surface 18, also called the outer side. It is therefore possible to mount the instrumented rolling bearing on a shaft, not shown, which would come into contact with the bore of the inner ring 6 without interference with the block 15. In addition, the block 15 is provided with an annular projection 20 issuing from the radial surface 18 and projecting outwards and axially in the direction of the rolling elements 3. The annular protuberance 20 projects into a groove 21 formed between the raceway 2 and the side face 4 of the outer ring 1 , symmetrical with the groove 12 in which the sealing gasket 11 is arranged. To promote the attachment operation of the sensor block in the groove, the annular protuberance can be in the form of a plurality of segments.

The outer ring 1 can therefore be of the standard type, symmetrical with respect to a radial plane perpendicular to the axis of the rolling bearing.

The block 15 is provided with a concave housing 22 in the form of a cell open on the cylindrical outer surface 17 and having a flat bottom and side walls perpendicular to said flat bottom. The housing 22 may be of parallelepiped shape. One or more connection pins 23, made of electrically conductive material, are arranged in the block 15 and projecting into the housing 22 without protruding from said housing 22 towards the outside. In other words, the pins 23 are set back relative to the external cylindrical surface 17. The pins 23 are connected to the sensor 14 by one or more wires 24 embedded in the mass of the block 15.

A printed or integrated signal processing circuit can be interposed between the sensor 14 and the connection pins 23.

The block 15 is further provided with an annular groove 25 open on the lateral surface 18 and of rectangular section. The groove 25 is concentric with the rolling bearing and has a diameter corresponding substantially to that of the outer surface of the inner ring 6. An encoder 26 comprises an active part 27 and a support 28. The support 28 is in the form of a sheet metal ring fitted on the outer surface of the inner ring 6 on the side opposite to the seal 11. The active part 27, for example made of synthetic material in which magnetic particles are embedded, is mounted on a part of the surface outside of the support 28 and secured to the latter, for example by overmolding. The sensor 14 is flush with the outer annular surface of the groove 25 and is arranged facing and with a small radial air gap relative to said active part 27.

Thus, the sensor assembly 13 has a generally annular shape with the exception of the housing 22 which, being hollow, is not likely to cause discomfort during handling or movement. Similarly, the instrumented rolling bearing also has a generally annular shape with the exception of the housing 22. The sensor 14 disposed in the groove 25 is suitably protected. A tight passage is provided between the radial face 8 of the inner ring 6 and a small diameter portion of the block 15 and also between said small diameter portion of the block 15 and the inner surface of the support 26 of the encoder 25. The sealing is therefore suitably ensured on the side of the sensor assembly 13. In FIG. 2, a slightly illustrated embodiment is illustrated different in that the housing 22 is open on the outer radial surface 19. The connection pins are oriented parallel to the axis of the rolling bearing. The sensor 14 is flush with an inner radial surface of the block 15. The support 26 of the encoder 25 has an L-shaped section with a cylindrical portion fitted on the inner ring 6 and a radial portion on which the active part is molded 27. The air gap is here axial. Again, the sensor assembly 13 and the instrumented rolling bearing have a generally annular shape with the exception of the housing 22. Said housing 22 is hollow and is therefore in no way liable to interfere with the handling or transport of these rooms.

In Figure 3, we see that the rolling bearing of Figure 2 has three pins 23 and a rounded notch 29 disposed on the cylindrical outer surface 17 of the block 15. The notch 29 forms an angular locating means allowing a positioning of the sensor assembly 13 relative to other elements outside the instrumented rolling bearing. The notch 29 allows for example to index the sensor unit with respect to the mechanical assembly for which the instrumented rolling bearing is intended. The notch 29 is of course in a predetermined and known angular position relative to the sensor 14. The angular position of the notch 29 can be identified, during assembly, by means of a roller 30 mounted on an arm 31 equipped with 'a spring 32. It is therefore possible to rotate the sensor assembly 13 or the instrumented rolling bearing to perform the angular indexing, this operation can be easily automated. The embodiment illustrated in FIG. 4 is close to that of FIG. 3, except that the notch 30, elongated axially, has a symmetrical V section. The identification can here be carried out by means of a knife 33 coming to rub on the cylindrical outer surface 17 under the action of a spring 34 and capable of immobilizing in rotation the sensor assembly 13 when the knife 33 comes to protrude into the '' notch 30.

In FIG. 5, a variant of FIG. 4 is illustrated, in which the notch 35 has on one side a stop surface 36 inscribed substantially in a plane passing through the axis of the rolling bearing, and on the other side an elongated slope 37. The means for locating the angular position of the notch 35 may comprise a finger 38 pressed against the cylindrical outer surface 17 by a spring 39 to abut against the surface 36. This device allows for indexing with a single possible direction of relative rotation of the sensor unit relative to the finger 38. In Figure 6, a bearing is shown instrumented bearing provided with a sensor assembly 13 of the type illustrated in FIG. 1, with a housing 22 in the form of an open cell on the cylindrical outer surface 17 and a notch 30 of the type illustrated in FIG. 4.

In FIG. 7, a variant of FIG. 3 is illustrated, in which the rounded notch 29 is arranged in a position diametrically opposite the housing 22 which is open on the radial surface 19.

In FIG. 8, a variant is illustrated in which are provided several notches and a housing 22 open on the cylindrical outer surface 17. More particularly, there is provided a notch 30, a notch 35, and a rounded notch 40 of smaller diameter as the notch 29, this by way of nonlimiting illustration of the types of notches that can be used. We have grouped together, on the same block 15, different types of notches so as not to multiply the drawings. However, it will be understood that in general a single notch is sufficient.

In the embodiment illustrated in Figures 9 and 10, the indexing notch 29 is similar to that of Figures 3 and 7, that is to say formed from the cylindrical outer surface 17 in the block 15. L 'notch 29 intersects the radial surface 19, for easier demolding and reduction of acute convex shapes which are not very solid and cutting. A concave housing 41 having the same functions as the housing 22 of the preceding figures is hollowed out from the cylindrical outer surface 17 and is axially distant from the radial surface 19 and from the radial face 4 of the outer ring 1.

The housing 41 comprises two identical cells 42 and 43 separated axially by a partition 44 limited by the cylindrical external surface 17. Each cell 42, 43 has the shape of a parallelepiped cut by the cylindrical external surface 17, with a length oriented in the circumferential direction, a width oriented in the radial direction, and a thickness oriented in the axial direction and less than the previous two. The housing 41 is spaced circumferentially from the indexing notch 29 so that these two elements are distinct and cannot be confused during indexing. Thus, a portion 45 of the cylindrical outer surface 17 extends circumferentially between the housing 41 and the indexing notch 29 over a non-zero angular sector and axially between the radial surface 19 of the block 15 and of the radial face 4 of the outer ring 1. In addition, the indexing notch 29 extends axially over a length greater than that separating the radial surface 19 and the surface of the partition 44 disposed on the side of the radial face 4 of the outer ring 1 It then suffices that the roller 30 of FIG. 3 or an equivalent means is of axial length greater than the axial dimension of the cell 42 closest to the radial surface 19 so that it cannot protrude into said cell 42 and that confusion between the housing 41 and the indexing notch 29 is avoided.

In addition, the block 15 comprises an electrical connection pin 46, 47 per cell 42, 43 of the housing 41. The pins 46 and 47 are flat and rectangular, being arranged in respective radial planes. The pins 46 and 47 are entirely disposed in the cells 42 and 43 and do not protrude from the cylindrical outer surface 17. In general, the housing of the block 15, provided with male pins, is designed to cooperate with a female connector provided with a cable for routing a signal from the sensor 14 to a processing and operating system, not shown. The connection pins are entirely disposed in the housing 22 or in the synthetic material of the block 15. The annular attachment protrusion 20 illustrated in FIGS. 1 and 2 can be replaced, as a variant, by a plurality of hooks each occupying a section limited angle to snap into the annular groove 21 of the outer ring 1 initially provided for fixing a seal. The central opening of the block 15 has an inner diameter greater than the diameter of the bore of the inner ring of the bearing. This greatly facilitates the handling, manual or automatic, of the instrumented bearing. It will be understood that the annular shape of the block 15 or of the sensor assembly 13 means that the latter has a central opening, preferably concentric with the rings of the bearing. In the variant illustrated in FIG. 11, the cell 22 is open on the radial surface 19. A printed circuit board 48 is mounted in the sensor holder block 15 and is connected to the sensor 14, and optionally supports said sensor 14. An extension 49 of the card 48 projects into the socket 22 and supports conductive tracks 50, here three in number, which perform the same function as the pins 23 in FIG. 3.

In the variant illustrated in FIG. 12, the cell is provided with a flat bottom 51 from which extend three female pins 52 arranged in the sensor holder block 15 and whose orifices 53 are flush with the bottom 51.

Of course, the examples illustrated are in no way limiting and one could conceive of other variants without departing from the scope of the invention. One could thus envisage a sensor unit comprising several cells provided with electrical connection means and at least one indexing means.

Therefore, thanks to the invention, an instrumented rolling bearing is produced whose characteristics make it possible to facilitate and automate its handling, its indexing and its mounting in the mechanical assembly for which it is intended.

Claims

1. Sensor block device (15) capable of being fixed on a ring of a bearing for the detection of the rotation parameter of a ring relative to the other ring, characterized in that the block holder sensor, of annular shape, comprises at least one cell (22) open to the outside and provided with electrical connection means, and at least one angular indexing means serving to achieve an adequate angular positioning of said block relative to one or more to references of the mechanical assembly for which the instrumented rolling bearing is intended, said indexing means being independent of the cell.

2. Device according to claim 1, characterized in that the electrical connection means are entirely arranged in said cell and / or in said sensor holder block.

3. Device according to claim 1 or 2, characterized in that the cell is open on an outer circular face (17) of the sensor holder block.

4. Device according to claim 1 or 2, characterized in that the cell is open on an inner circular face of the sensor holder block.

5. Device according to claim 1 or 2, characterized in that the cell is open on a radial face (19) of the sensor holder block located on the side opposite to a radial face (18) intended to come into contact with said Ring.

6. Rolling bearing, comprising a rotating ring (6), a non-rotating ring (1), a row of rolling elements (3) disposed between raceways of said rings, an encoder means (26) integral with the ring rotating, and a sensor means comprising a sensor (14) supported by a sensor holder block (15) secured to the non-rotating ring and arranged facing and with a small air gap relative to the encoder means whose scrolling during rotation is detected by the sensor, characterized in that the sensor-holder block, of annular shape, comprises at least one cell (22) open to the outside and provided with electrical connection means, and at least one angular indexing means used to achieve angular positioning adequate of said block with respect to one or more references of the mechanical assembly for which the instrumented rolling bearing is intended, said indexing means being independent of the cell.

7. Bearing according to claim 6, characterized in that the electrical connection means are entirely disposed in said cell and / or in said sensor holder block.

8. A bearing according to claim 6 or 7, characterized in that the sensor holder block has a bore with a diameter greater than that of the inner ring.

9. A bearing according to claim 6 or 7, characterized in that the sensor holder block has an outer diameter smaller than that of the outer ring.

10. Bearing according to any one of claims 6 to 9, characterized in that the sensor holder block has an outer front surface (19) planar.

11. Bearing according to any one of claims 6 to 10, characterized in that the sensor holder block comprises an annular rib (21) capable of cooperating with a groove of the non-rotating ring.

12. Bearing according to any one of claims 6 to 11, characterized in that the angular indexing means comprises a notch of generally axial shape on an outer surface of the sensor holder block.

13. A bearing according to claim 12, characterized in that said outer surface of the sensor holder block is cylindrical or radial.

14. A bearing according to claim 12 or 13, characterized in that the notch is of rounded or V-shaped section, symmetrical or asymmetrical.

15. Electric motor comprising a bearing according to any one of claims 6 to 14.