Steering Bellows

Abstract

A steering bellows 1 comprising a sleeve 2 delimited by an outer peripheral side wall 3, said sleeve 2 comprising, in axial succession, at least one first annular end portion called large base 4, a portion 5 deformable in the direction in which said bellows 1 expands or contracts, formed by successive coaxial turns, and a second annular end portion called small base 6, said sleeve 2 comprising a transition region 7 between the deformable portion 5 and the large base 4, said transition region 7 comprising a radial outlet 8 provided in the outer peripheral side wall 3 of the sleeve 2. The radial outlet 8 is closed by a tubular end connector 9 attached to said radial outlet 8 and having a first end 10 connected to the radial outlet 8 and an opposite closed end 11, said end connector 9 extending outside the sleeve 2, said end connector 9 defining inside a cavity 10 housing at least one fluid-tight sensor 13 of said bellows.

Description

[Technical field]

[0001] This invention relates to steering bellows.

[0002] The invention relates in particular to a steering bellows comprising a sleeve delimited by an outer peripheral side wall, said sleeve comprising, in axial succession, at least one first annular end portion, called the large base, capable of forming an end portion for fixing the bellows to a first steering element, such as a steering housing or casing, to be protected, a portion deformable in the direction in which the bellows can be expanded or contracted, formed by successive coaxial turns, and a second annular end portion, called the small base, capable of forming an end portion for fixing the bellows to a second steering element, such as a steering tie rod, to be protected, said sleeve comprising a transition region between the deformable portion and the large base, in which a radial outlet is formed in the outer peripheral side wall of the sleeve. [Background technology]

[0003] In a rack-steering system for a motor vehicle, a steering pinion is rotatably connected to a steering column operated by means of the steering wheel of the vehicle, the pinion meshing with a rack mounted to slide longitudinally within a steering casing, the ends of the rack external to the casing being connected to steering tie rods respectively associated with the right and left steering wheels of the vehicle, the tie rods ensuring the connection between the rack and each stub axle. Thus, a rotation of the steering wheel in one direction or the other, and therefore a corresponding rotation of the steering pinion, is translated into a corresponding translation of the rack, which itself, via the tie rods and the stub axles, directs the wheels of the vehicle to turn right or left.

[0004] In such rack-steering systems, the articulation link between each end of the rack and the corresponding tie rod is a ball joint link, called an "axial" ball joint, created by an axial ball joint housing fixed to the end of the rack and an axial ball joint pivot with a spherical head fixed to the tie rod and mounted for rotation in any direction within the axial ball joint housing.

[0005] Considering the mobility of the rack relative to the steering casing and the variability of the orientation of the tie rod relative to the end of the rack, the protection of the steering system in the area of ​​each axial ball joint is usually ensured by surrounding the end of the rack (which is outside the casing) and the axial ball joint with a bellows which connects the adjacent end of the steering casing to the corresponding tie rod. The annular end of the bellows is fixed around the end of the steering casing by tightening a first mounting collar around this end. The other annular end of the bellows is fixed around the tie rod or the axial ball joint pivot by tightening a second mounting collar around this other end. Fixed in this way, the bellows ensures the tightness of the gap between the steering casing and the tie rod.

[0006] Between the two ends thus attached, the bellows has a specific number of turns, which enables it to expand or contract according to the position of the rack relative to the steering casing, and also enables the same bellows to flex according to the variable orientations assumed by the tie rods through their ball-joint articulation.

[0007] Automotive rack steering systems are usually manufactured to be completely sealed to prevent unwanted water or moisture from entering the steering interior.

[0008] The advantage of such a fully manual steering system is that it is easier to detect steering anomalies resulting from corrosion if a problem occurs, especially if the bellows loses its tightness. However, with the development of autonomous vehicles and cable-type steering control, there is no longer necessarily a direct mechanical connection between the steering wheel and the rest of the steering system. As a result, it becomes more difficult to detect rack damage associated with the loss of the bellows' tightness. Now, the loss of the bellows' tightness must be detected very quickly, otherwise there is a risk that the rest of the steering system will deteriorate very quickly. As shown in Korean Patent Application Publication No. 1020130128622, a bellows is known that has a radial outlet closed by a closing piece. As shown in Japanese Patent Application Publication No. 2012224274 and Japanese Patent Application Publication No. 2012240435, a bellows that houses at least one sensor is known. However, these sensors are not very satisfactory because they lack responsiveness. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Application Publication No. 1020130128622 [Patent Document 2] Patent Publication No. 2012224274 [Patent Document 3] Patent Publication No. 2012240435 Summary of the Invention [Problem to be solved by the invention]

[0010] One object of the invention is to propose a steering bellows design that can be adapted to any type of steering system, without compromising the possibility of detecting any faults in terms of the tightness of the bellows.

[0011] Another object of the invention is to propose a steering bellows design that makes it possible to detect loss of tightness of the bellows in a very short time. [Means for solving the problem]

[0012] To this end, the subject of the invention is a steering bellows comprising a sleeve delimited by an outer peripheral side wall, said sleeve comprising, in axial succession, at least one first annular end portion called the large base, a portion deformable in the direction in which the bellows expands or contracts, formed by successive coaxial turns, and a second annular end portion called the small base, said sleeve comprising a transition region between the deformable portion and the large base, said transition region having a radial outlet formed in the outer peripheral side wall of the sleeve, said radial outlet being closed by a tubular end connector, which is added to said radial outlet and has a first end connected to the radial outlet and an opposite closed end, said end connector extending outside the sleeve, said end connector defining inside a cavity housing at least one sensor of the fluid-tightness of the bellows. The installation and maintenance of at least one fluid tightness sensor, i.e. a sensor for determining parameters representative of the tightness of the bellows to fluids, i.e. liquids and gases, can be facilitated by integrating this sensor in a tubular end connector that is external to the sleeve, i.e. extending protruding from the sleeve. By end connector external to the sleeve is understood an end connector that does not protrude into the sleeve. The first end of the end connector does not extend protruding from the radial outlet opening of the sleeve into the sleeve. Thus, the risk that the end connector forms an obstacle to the flow of the radial outlet fluid inside the sleeve by its first end is avoided. The first end of the end connector extends in the best conditions flush with the radial outlet opening of the sleeve. This design, in which the end connector is external to the sleeve, allows water that may be present in the sleeve due to a loss of sealing tightness to be easily guided to the sensor without crossing any obstacle. By end connector external to the sleeve is understood an end connector that extends protruding from the sleeve.The presence of such a sensor, and its design combined with the design of the end connectors and radial exits, allows for quick and easy detection of loss of bellows tightness, regardless of the type of steering system. This loss of bellows tightness or bellows leakage can be the result of a hole resulting from wear in the bellows, or simply a gap.

[0013] According to one embodiment of the invention, the end connector includes a peripheral flange arranged to bear against the periphery of the radial outlet when the end connector is in a mated condition with the sleeve, thereby facilitating fastening of the end connector and facilitating a sealing fit between the end connector and the sleeve.

[0014] According to one embodiment of the invention, the bellows fluid tightness sensor is an electrical sensor with at least one electrical wire, the electrical wire or at least one of the electrical wires protruding from the end connector through the closed end of the end connector, this design allows easy subsequent connection of the sensor to a control unit.

[0015] Alternatively, the fluid tightness sensor comprises an energy store, said fluid tightness sensor communicating wirelessly with a remote terminal.

[0016] SUMMARY OF THE PRESENT EMBODIMENT In accordance with one embodiment of the present invention, an end connector includes a tubular body having opposite ends that are open, and a cover for closing one end of the body to form a closed end of the end connector.

[0017] According to one embodiment of the invention, the cover is at least snapped, screwed, glued or welded to the body and the sensor, or at least one of the sensors, is fixed to the cover. This arrangement allows for easy attachment of the sensor.

[0018] According to one embodiment of the invention, the end connector is a one-piece monolithic part, again allowing for easy attachment of the sensor.

[0019] According to one embodiment of the invention, the or at least one of the fluid tightness sensors of the bellows is a gas concentration measurement sensor. This solution has the advantage of being insensitive to harmful media of the rack and allows continuous detection of any leaks in the bellows.

[0020] According to one embodiment of the invention, the or at least one of the bellows fluid tightness sensors is a liquid detection sensor. This design allows for easy implementation.

[0021] According to one embodiment of the present invention, the or at least one of the bellows fluid tightness sensors is a pressure sensor or a flow sensor.

[0022] Thus, at least one of the fluid tightness sensors of the bellows can be selected from sensors including a gas concentration measurement sensor, a liquid detection sensor, a pressure sensor, a flow sensor. According to an embodiment of the invention, the end connector is fixed by overmolding to the radial outlet. According to an embodiment of the invention, the outer peripheral side wall of the sleeve is provided, on its inner side facing the inside of the sleeve, with an inner circumferential groove that exits to the radial outlet of the sleeve. The presence of this groove can form a guide for the flow of fluid towards the radial outlet. According to an embodiment of the invention, the inner circumferential groove extends over a part of the inner circumference of the sleeve.

[0023] The invention will be better understood upon reading the following description of exemplary embodiments with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0024] [Figure 1] Schematic diagram of the steering system. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a bellows when coupled to an element of a steering system. [Diagram 3] 1 is a schematic diagram of a bellows according to the present invention; [Figure 4] FIG. 4 is a detailed view of the end connector of FIG. 3. [Diagram 5] 1 is a schematic diagram of a bellows according to the present invention; [Figure 6] FIG. 6 is a detailed view of the end connector of FIG. 5. [Figure 7] FIG. 13 is a partial view of a bellows having an inner circumferential groove in a sleeve. [Figure 8] FIG. 13 is a partial view of a bellows having an inner circumferential groove in a sleeve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] As described herein above, the present invention relates to a steering bellows 1 that can be incorporated into a steering system of the type represented in FIG. 1, which is a rack steering system for an automobile.

[0026] In this steering system, a steering column 22 is operated using a steering wheel 20. The steering column 22 is rotatably fixed to a pinion 21 which meshes with a rack 23 mounted to slide longitudinally within a steering casing 24.

[0027] The ends of the rack 23 external to the casing 24 are coupled to steering tie rods 25 associated respectively with the right and left steering wheels 26 of the vehicle.

[0028] Thus, a rotation of the steering wheel in one direction or the other, and therefore a corresponding rotation of the steering pinion, is translated into a corresponding translation of the rack, which, itself, via the tie rod and stub axle, orients the vehicle's wheels to turn right or left.

[0029] In such a rack steering system, the articulation link between each end of the rack 23 and the corresponding tie rod 25 is a ball joint link, called an axial ball joint, created by an axial ball joint housing fixed to the end of the rack 23 and an axial ball joint pivot having a spherical head fixed to the tie rod 25 and mounted for rotation in any direction within the axial ball joint housing.

[0030] The steering bellows 1 comprises a sleeve 2 delimited by an outer peripheral side wall 3. The sleeve 2 is preferably cylindrical with a tapered shape. This sleeve 2 is generally manufactured from a synthetic material by injection or blow molding and comprises, in axial succession, at least one first annular end portion, called a large base 4, capable of forming an end portion for fixing the bellows 1 to a first steering element, such as a steering housing or casing 24, to be protected, a portion 5 deformable in the direction in which the bellows 1 can expand or contract, formed by successive coaxial turns, and a second annular end portion, called a small base 6, capable of forming an end portion for fixing the bellows 1 to a second steering element, such as a steering tie rod 25, to be protected. The sleeve 2 also comprises a transition region 7 between the deformable portion 5 and the large base 4.

[0031] Taking into account the mobility of the rack 23 relative to the steering casing 24 and the variability of the orientation of the tie rods 25 relative to the ends of the rack 23, protection of the steering system in the area of ​​each axial ball joint is therefore ensured by the bellows 1 connecting the adjacent ends of the steering casing 24 to the corresponding tie rods 25, surrounding the ends of the rack (which are outside the casing) and the axial ball joints.

[0032] The large base 4 of the bellows 1 is fixed around the end of the steering casing 24 by tightening a first mounting collar around the end of the steering casing 24. The small base 6 of the bellows 1 is fixed around the tie rod 25 or axial ball joint pivot by tightening a second mounting collar around the small base 6.

[0033] The deformable portion 5 of the steering bellows 1 allows the bellows to expand or contract depending on the position of the rack 23 relative to the steering casing 24 .

[0034] The sleeve 2 has a radial outlet 8 formed in the outer peripheral side wall 3 of the sleeve 2 at a transition region 7. This radial outlet 8 is closed by a tubular end connector 9 applied to said radial outlet 8.

[0035] The tubular end connector 9 has a first end 10 connected to the radial outlet 8 and an opposite closed end 11. The closed end of the tubular end connector 9 preferably constitutes the lower position of the bellows when it is in the mounted state in the steering system. The end connector 9 extends outside the sleeve 2 without protruding into the sleeve 2. The end connector 9 does not extend into the sleeve beyond the opening of the radial outlet 8 in the sleeve. Therefore, the end connector 9 cannot impede the flow of fluid inside the radial outlet 8. The end connector 9 can be straight, as in the illustrated example, or it can be curved or have any other kind of shape without departing from the invention. The end connector 9 defines inside a cavity 12 that accommodates at least one sensor 13 for determining a parameter representative of the fluid tightness of the bellows 1.

[0036] A leak in the bellows can be detected by this or these tightness sensors 13. Indeed, rack steering systems in motor vehicles are usually manufactured completely sealed to avoid unwanted ingress of water or moisture inside the steering system.

[0037] As noted above, the end connectors 9 can take many forms.

[0038] Regardless of the embodiment, the end connector 9 includes a peripheral flange 14 arranged to press against the periphery of the radial outlet 8 of the sleeve when the end connector 9 is in a coupled condition with the sleeve 2 .

[0039] The compression is maintained by overmolding the end connector 9 when it is an insert placed in a bellows manufacturing mould during the manufacture of the sleeve 2. Obviously, other embodiments of connecting the end connector 9 to the sleeve 2 are possible. Thus, snap-fitting, gluing or welding etc. are conceivable.

[0040] 3 and 4, the end connector 9 is a one-piece monolithic part. The fluid, i.e. gas and liquid, tightness sensor 13 of the bellows 1 is therefore pre-placed in the cavity 10 of the end connector 9, which is then fixed to the sleeve 2.

[0041] In the example shown in Figures 5 and 6, the end connector 9 comprises a tubular body 16 open at each end and a cover 17 for closing one end of the body 16 to form a closed end 11 of the end connector 9.

[0042] The cover 17 may be snapped, screwed, glued, or welded to the body 16 .

[0043] The sensor 13, or at least one of the sensors 13, is preferably fixed to the cover 17. In the case of a snap fit, it is particularly easy to replace the sensor 13 in the event of a malfunction.

[0044] In this embodiment, the body 16 and sleeve 2 of the end connector 9 can be pre-assembled by welding during the manufacture of the sleeve, and then the fluid tightness sensor 13 fixed to the cover 17 is installed simply by fixing the cover 17 to the body 16.

[0045] In the illustrated example, the bellows fluid tightness sensor 13 is an electrical sensor having at least one electrical wire 15, the electrical wire 15, or at least one of the electrical wires, protruding from the end connector 9 through the closed end 11 of the end connector 9.

[0046] By means of this wire or these wires the sensor or sensors can be connected to a control unit, not shown.

[0047] Said control unit may take the form of an electronic and computing system, for example comprising a microprocessor and a working memory. According to a particular embodiment, the control unit may take the form of a programmable logic controller.

[0048] In other words, the functions and steps described can be implemented in the form of a computer program or by hardware components (e.g. programmable gate arrays). In particular, the functions and steps performed by the drive unit or its modules can be generated by an instruction set or computing module implemented in a processor or controller, or by dedicated electronic components or components of the programmable logic circuit type (or FPGA, an acronym for field-programmable logic array) or application-specific integrated circuit (or ASIC) type. It is also possible to combine computing and electronic components.

[0049] When a unit, or a means or module of said unit, is specified as being configured to perform a given operation, it means that the unit comprises computing instructions and corresponding execution means enabling said operation to be performed, and / or that the unit comprises corresponding electronic components.

[0050] This or these tightness sensors 13 for the fluids of the bellows, ie liquids and gases, can also take many forms.

[0051] Thus, the fluid tightness sensor 13 of the bellows 1, or at least one of the fluid tightness sensors 13, can be a sensor for detecting liquids, in particular water. In this case, the end connector 9 forms a low position of the bellows when the bellows is in a position arranged in the steering system. The bellows extends with the longitudinal axis of the sleeve, represented in FIG. 2 as XX', in a horizontal position. The low position of the bellows is formed by the end connector 9 with the sensor 13, so that when the bellows is no longer sealed, water can enter the bellows and come to be located in the end connector by gravity. This water can also be the result of condensation of moisture in the bellows.

[0052] The presence of this water is detected by the sensor 13. This information is transmitted to a control unit which can then issue a control signal for an alarm device, such as a device that emits a sound or light signal.

[0053] Alternatively or additionally, the fluid tightness sensor 13 of the bellows 1, or at least one of the fluid tightness sensors 13, can be a gas concentration measuring sensor. In this embodiment, gas can be introduced into the bellows when the bellows is mounted to the rest of the steering system.

[0054] The presence of this gas can be measured continuously in real time by the sensor 13. In case of a leak in the bellows, a drop in the concentration of gas is observed by comparison with a predefined value. In case of a problem, again the control unit to which the signal from the sensor 13 is sent can issue a control signal for an alarm device.

[0055] The gas concentration sensor 13 may be a sensor for measuring carbon monoxide (CO) in the air. This sensor for measuring CO in the air may be an infrared sensor or may incorporate a chemical reagent in a manner known per se.

[0056] Obviously, the concentration of other gases, such as oxygen or nitrogen, may also be measured without departing from the scope of the present invention.

[0057] Alternatively or additionally, the fluid tightness sensor 13 of the bellows 1, or at least one of the fluid tightness sensors 13, can be a pressure sensor. The bellows is connected to a pressure source. A leakage measurement is performed by loss of pressure. This solution is not preferred as it requires a substantial experimentation phase.

[0058] Alternatively or additionally, the tightness sensor 13, or at least one of the tightness sensors 13, can be a flow sensor. In this embodiment, a certain air flow is injected into the bellows and the flow loss is measured at the radial outlet. Again, this solution is not preferred as it requires a substantial experimental phase.

[0059] To complete the bellows, the outer peripheral side wall 3 of the sleeve 2 can be provided, on its inner side facing the inside of the sleeve 2, with an inner circumferential groove 18 that exits at the radial outlet (8) of the sleeve 2. This groove 18, the presence of which makes it possible to guide the fluid resulting from the loss of tightness to the radial outlet 8 into contact with the sensor. Again, this arrangement makes it possible to increase the response speed of the sensor. In the example shown, the inner circumferential groove 18 extends over a portion of the inner circumference of the sleeve 2. Obviously, this inner circumferential groove 18 could extend over the entire inner circumference of the sleeve without departing from the scope of the invention.

Claims

1. A steering bellows (1) comprising a sleeve (2) bounded by an outer peripheral side wall (3), said sleeve (2) comprising, in axial succession, at least one first annular end portion called a large base (4), a portion (5) deformable in the direction in which said bellows (1) is expanded or contracted, said portion (5) being formed by successive coaxial turns, and a second annular end portion called a small base (6), said sleeve (2) comprising a transition region (7) between said deformable portion (5) and said large base (4), said transition region (7) being connected to said outer peripheral side wall (3) of said sleeve (2).

1. A steering bellows (1) having a radial outlet (8) formed therein, the radial outlet (8) being closed by a tubular end connector (9) added to the radial outlet (8) and having a first end (10) connected to the radial outlet (8) and an opposite closed end (11), the end connector (9) extending outside the sleeve (2), the end connector (9) defining therein a cavity (12) for housing at least one sensor (13) for the fluid-tightness of the bellows.

2. 2. A steering bellows (1) according to claim 1, characterized in that the end connector (9) comprises a peripheral flange (14) arranged to press against the periphery of the radial outlet (8) when the end connector (9) is in a connected state with the sleeve (2).

3. 3. A steering bellows (1) according to claim 1 or 2, characterized in that the fluid tightness sensor (13) of the bellows is an electric sensor comprising at least one electric wire (15), the electric wire (15), or at least one of the electric wires (15), protruding from the end connector (9) through the closed end (11) of the end connector (9).

4. 4. A steering bellows (1) according to any one of claims 1 to 3, characterized in that the end connector (9) comprises a tubular body (16) open at each of its two ends and a cover (17) for closing one end of the body (16) to form a closed end (11) of the end connector (9).

5. 5. A steering bellows (1) according to claim 4, characterized in that the cover (17) is at least snap-fitted, screwed, glued or welded to the body (16) and the sensor (13), or at least one of the sensors (13), is fixed to the cover (17).

6. A steering bellows (1) according to any one of claims 1 to 3, characterised in that the end connector (9) is a one-piece monolithic part.

7. 7. A steering bellows (1) according to claim 1, characterized in that the fluid tightness sensor (13) of the bellows (1), or at least one of the fluid tightness sensors (13), is a gas concentration measurement sensor.

8. 8. A steering bellows (1) according to claim 1, characterized in that the fluid tightness sensor (13) of the bellows (1), or at least one of the fluid tightness sensors (13), is a liquid detection sensor.

9. 9. A steering bellows (1) according to any one of the preceding claims, characterized in that the fluid tightness sensor (13) of the bellows (1), or at least one of the fluid tightness sensors (13), is a pressure sensor or a flow sensor.

10. 10. Steering bellows (1) according to any one of the preceding claims, characterized in that the end connectors (9) are fixed to the radial outlets (8) by overmolding.

11. 11. A steering bellows (1) according to any one of claims 1 to 10, characterized in that the outer peripheral side wall (3) of the sleeve (2) is provided, on its inner side directed towards the inside of the sleeve (2), with an inner peripheral groove (18) that exits into the radial outlet (8) of the sleeve (2).

12. 12. Steering bellows (1) according to claim 11, characterized in that the inner circumferential groove (18) extends over a part of the inner circumference of the sleeve (2).

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