Steering system for a wheeled vehicle having at least two steerable wheels and method for controlling the operation of such a steering system
Patent Information
- Application Number
- JP2024522551
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-10-28
- Filing Date
- 2022-10-27
- Publication Date
- 2025-08-15
AI Technical Summary
Existing rack-and-pinion steering systems, particularly in automobiles, face issues with corrosion and fluid ingress, leading to undetectable deterioration in steering operation when there is no mechanical connection between the steering member and the rack.
A steering system with a sealed design using bellows to protect articulated connections and a monitoring device with sensors to detect gas-tightness, allowing real-time monitoring for corrosion prevention by detecting loss of tightness.
Enables continuous, real-time monitoring of steering system integrity, preventing corrosion and ensuring reliable steering performance by quickly reporting any loss of tightness.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to a steering system for a wheeled machine having at least two steered wheels, and in particular to a method for controlling the operation of such a steering system.
[0002] The invention particularly relates to a steering system for a wheeled machine having at least two steered wheels, said steering system comprising: - Racks, - a steering casing arranged around the rack; - at least one member for imparting an axial sliding movement of the rack inside the steering casing; - two steering connecting rods having one end connected to the end of the rack by an articulated connection and an opposite end connectable to one of the steered wheels of the machine; - two bellows, each protecting the articulated joint and each connecting the connecting rod to the steering casing, the bellows and the steering casing defining a closed volume that is at least airtight against the outside air; Equipped with. [Background technology]
[0003] Such rack-and-pinion steering, especially for motor vehicles, is well known to the person skilled in the art. As mentioned above, such steering is manufactured in a completely sealed manner so as to avoid any ingress of fluids in the form of gas or liquid into the steering casing. In the case of a mechanical connection between the rack and the member for controlling the steering, such as a steering wheel, it is easy for the driver, for example via a steering column driven in rotation by the steering wheel, to detect a disturbance or deterioration in the operation of the steering, resulting for example from corrosion. This detection may no longer be effective when there is no mechanical connection between the rack and the member for controlling the steering.
[0004] Document DE102012019427 describes a steering system having a control unit arranged to measure pressure curves when the wheels are steered to the left or to the right. The characteristics of these pressure curves are analysed in order to detect any leaks in the steering system. Such a steering system is complex. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] DE102012019427 Summary of the Invention
[0006] The object of the invention is to propose a steering system whose design makes it possible to detect a deterioration or the risk of a deterioration in the steering action, regardless of how the movement of the member for controlling the steering, such as the steering wheel, is transmitted to the rack.
[0007] To this end, the subject of the invention is a steering system for a wheeled machine having at least two steered wheels, comprising a rack, a steering casing arranged around the rack, at least one member for driving the axial sliding movement of the rack inside the steering casing, two steering connecting rods having one end connected to the end of the rack by an articulated joint and an opposite end connectable to one of the steered wheels of the machine, and two bellows, each protecting the articulated joint and each connecting the connecting rod to the steering casing, the bellows and the steering casing defining a closed volume that is at least gas-tight against the outside air, characterized in that the steering system comprises a monitoring device, the monitoring device comprising at least one sensor for determining a parameter representative of the gas-tightness of the closed volume defined by the bellows and the steering casing. By detecting a loss of gas-tightness of the steering system, corrosion of the steering system and thus failure of the steering system can be prevented. Such detection makes it possible to continuously monitor the tightness of the steering system in real time.
[0008] According to an embodiment of the invention, the closed volume delimited by the bellows and the steering casing is at least partially pre-filled with a gas, referred to as filling gas, and said sensor or at least one of said sensors for determining a parameter representative of at least the gas-tightness of the closed volume delimited by the bellows and the steering casing is a sensor for determining the presence or gas concentration of said filling gas inside the closed volume, which results in easier monitoring.
[0009] According to one embodiment of the invention, the steering system comprises at least one closable gas intake orifice communicating with a volume delimited by the bellows and the steering casing with a filling gas, said gas intake orifice being in a closed state when said volume is in a pre-filled state, so that it is possible to inject a filling gas through the gas intake orifice, which gas injection causes the already present gas to be expelled through the gas discharge orifice.
[0010] According to one embodiment of the invention, the or at least one of the sensors for determining a parameter representative of the at least gas-tightness of the closed volume delimited by the bellows and the steering casing is arranged on the steering casing, which results in a reliable positioning of the sensor or at least one of the sensors. In one variant, the sensor or at least one of the sensors for determining a parameter representative of the at least gas-tightness of the closed volume delimited by the bellows and the steering casing is arranged on at least one of the bellows.
[0011] According to one embodiment of the invention, the sensor or at least one of the sensors for determining a parameter representative of the at least gas-tightness of the closed volume delimited by the bellows and the steering casing is an infrared measurement sensor.
[0012] According to an embodiment of the invention, the monitoring device comprises a device for emitting an audible or luminous warning signal and a control unit, said control unit being configured to obtain data provided by at least one sensor for determining a parameter representative of the at least gas-tightness of the closed volume and to control the device for emitting an audible or luminous warning signal depending on said data, so that a loss of tightness can be reported quickly in order to avoid any deterioration of the steering system resulting from the loss of tightness.
[0013] According to one embodiment of the invention, the member for driving the axial sliding movement of the rack inside the steering casing is a rotating member meshingly engaged with the rack, and the steering system comprises at least one member for rotationally driving the member for driving the axial sliding movement of the rack inside the steering casing. The member for driving the axial sliding movement of the rack inside the steering casing, which is a rotating member meshingly engaged with the rack, is typically a gear member, such as a pinion or a gear. The member for rotationally driving the member for driving the axial sliding movement of the rack inside the steering casing may for its part be formed by a steering column, the movement of which is itself driven by the steering wheel or by an electric actuator, such as a motor, the movement of which is controlled in response to the actuation of the steering wheel, for example.
[0014] A further subject of the invention is a method for controlling a steering system for a wheeled machine having at least two steered wheels, said steering system comprising a rack, a steering casing arranged around the rack, a member for driving an axial sliding movement of the rack inside the steering casing, two steering connecting rods having one end connected to an end of the rack by an articulated connection and an opposite end connectable to one of the steered wheels of the machine, and two bellows, each protecting the articulated connection and each connecting the connecting rod to the steering casing, the bellows and the steering casing defining a closed volume that is at least tight against the outside air, the steering system being of the aforementioned type, characterized in that the method comprises at least one step of determining a parameter representative of the tightness at least against gas of the closed volume defined by the bellows and the steering casing.
[0015] According to one embodiment of the method, prior to the step of determining a parameter representative of at least a gas-tightness of the closed volume delimited by the bellows and the steering casing, the method comprises a step of at least partially pre-filling the closed volume with at least one filling gas, and the step of determining a parameter representative of at least a gas-tightness of the closed volume delimited by the bellows and the steering casing is a step of determining the presence or gas concentration of said filling gas inside the closed volume.
[0016] According to one embodiment of the method implementation, the monitoring device comprises a device for emitting an audible or luminous warning signal and a control unit, the method comprising a step of acquiring by the control unit data provided by a sensor for determining a parameter representative of at least a gas-tightness of the closed volume, and a step of controlling the device for emitting an audible or luminous warning signal in response to the data.
[0017] The invention will be more clearly understood from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]
[0018] [Figure 1] 1 shows a partial front view of a steering system according to the present invention. [Diagram 2] FIG. 1 shows a partial cross-sectional view of a steering system according to the present invention. [Diagram 3] The elements of the steering system are shown in block form. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] As mentioned above, the present invention relates to a steering system 1 for a wheeled machine (not shown) having at least two steered wheels, such as a motor vehicle.
[0020] As shown in Figure 2, the steering system 1 comprises a rack 2 having two ends. In particular, the rack 2 is generally in the form of a lоngilinear element, extending longitudinally between the two ends of said element. The linear element is provided with teeth. The rack 2 is generally made of metal.
[0021] The steering system 1 also comprises a steering casing 3 arranged around the rack 2. This steering casing 3 forms a tubular covering open at each of its ends. This steering casing 3 surrounds the rack 2 so that the two ends of the rack protrude from said casing 3.
[0022] The steering system 1 also comprises a member 4 for imparting an axial sliding movement of the rack 2, said member being arranged inside the steering casing 3. In the example shown, this member 4 for imparting an axial sliding movement of the rack 2 inside the steering casing 3 is a rotating member, in particular a toothed pinion meshingly engaged with the teeth of the rack 2.
[0023] This member 4 for driving the axial sliding movement of the rack 2 inside the steering casing 3 is shown in this case also engaged with a steering column 15. This steering column 15 is a rotating column that can be steered by means of a steering wheel (not shown). Conventionally, rotation of the steering wheel drives a rotation of the column 15 and the toothed pinion and thus an axial sliding movement of the rack, i.e. an axial sliding movement of the rack parallel to its longitudinal axis in one direction or the other depending on the direction of rotation of the steering wheel.
[0024] In one variant, the member 4 for propelling the axial sliding movement of the rack 2 inside the steering casing 3 can be driven in rotation by an electric actuator such as a motor, cylinder or the like, the rotation being controllable from a so-called electric steering wheel.
[0025] The steering system 1 also comprises two connecting rods 5. Thus, the two ends of the rack protruding from the casing 3 are connected to steering connecting rods 5 respectively associated with the left and right steered wheels (not shown) of the wheeled machine.
[0026] The connection between one end of the rack 2 and the connecting rod 5 is an articulated connection 6. The articulated connection 6 between each end of the rack 2 and the corresponding connecting rod 5 is therefore a ball joint connection, called an axial ball joint, made by an axial ball joint housing fixed to the end of the rack and by an axial ball joint pivot with a spherical head fixed to the connecting rod and mounted to rotate in any direction within the axial ball joint housing.
[0027] That end of the connecting rod 5 opposite the end connected to the rack 2 can be connected to a wheel, in particular to a steering knuckle of the wheel.
[0028] Thus, in a manner known per se, a rotation of the steering wheel in one direction or the other, and therefore a corresponding rotation of the steering pinion, is converted into a corresponding translation of the rack, which, via the connecting rod and the steering knuckle, causes the wheels to turn right or left per se.
[0029] The steering system 1 also comprises two bellows 7 , each protecting one of the articulated connections 6 and each connecting a connecting rod 5 to the steering casing 3 .
[0030] In the example shown, each bellows comprises a sleeve delimited by a peripheral side wall. The sleeve is preferably cylindrical or cylindroconic. This sleeve, generally manufactured from a synthetic material by injection or blow molding, comprises, in axial succession, at least one first annular end portion, called the large base, capable of forming an end for fastening the bellows to the steering casing 3 to be protected, a portion deformable in the direction of elongation or shortening of the bellows 7 formed by the continuation of coaxial rotations, and a second annular end portion, called the small base, capable of forming an end for fastening the bellows 7 to the steering connecting rod 5.
[0031] Taking into account the mobility of the rack 2 relative to the steering casing 3 and the changeable orientation of the connecting rod 5 relative to the ends of the rack 2, protection of the steering in the area of each axial ball joint is therefore ensured by bellows 7 which connect the adjacent end of the steering casing 3 to the corresponding connecting rod 5 by surrounding the rack ends (outside the casing) and the axial ball joints.
[0032] The large base of the bellows 7 is fastened around the end of the steering casing 3 by a first mounting collar which is fixedly secured around this end, and the small base of the bellows 7 is fastened around the connecting rod 5 or axial ball joint pivot by a second mounting collar which is fixedly secured around this small base.
[0033] The deformable portion of the steering bellows 7 allows the bellows 7 to be extended or shortened depending on the position of the rack 2 relative to the steering casing 3 .
[0034] The bellows 7 and the steering casing 3 delimit a volume 8 which is closed so as to be at least tight against the outside air. In practice, this volume 8 is closed so as to be tight against fluids, i.e. against gases and against liquids.
[0035] To check such tightness, the steering system 1 comprises a monitoring device 9. This monitoring device 9 comprises at least one sensor 10 for determining a parameter representative of the tightness, at least with respect to gas, of the closed volume 8 delimited by the bellows 7 and the steering casing 3.
[0036] Preferably, the closed volume 8 delimited by the bellows 7 and the steering casing 3 is at least partially pre-filled with a gas, referred to as the filling gas, and the sensor 10 or at least one of the sensors 10 for determining a parameter representative of the gas-tightness of the volume 8 delimited by the bellows 7 and the steering casing 3 against at least gas is a sensor for determining the presence or gas concentration of said filling gas inside the closed volume 8.
[0037] In order to enable the volume 8 to be at least partially pre-filled with filling gas in this manner, the steering system 1 is provided with at least one closeable gas intake orifice 11 communicating with the volume 8 and, optionally, a closeable gas discharge orifice 12, the gas intake orifice 11 and, if present, the gas discharge orifice 12 being in a closed state when the volume 8 is in a pre-filled state.
[0038] Thus, during manufacture of the steering system, the gas inlet orifice 11 and the gas outlet orifice 12 which communicate with the volume 8, i.e. open into the volume 8, are open. The fill gas is injected into the volume 8 via the gas inlet orifice 11 and releases the gas already contained in the volume 8 via the gas outlet orifice 12.
[0039] When this filling gas is considered to have been sufficiently injected, the gas intake orifice 11 and the gas exhaust orifice 12 are hermetically closed, and one or more sensors 10 for determining a parameter representative of the hermeticity of the closed volume 8 at least against gas can then provide information regarding the presence or gas concentration of said filling gas in the volume 8.
[0040] In the example shown, a sensor 10 for determining a parameter representative of the at least gas-tightness of the closed volume delimited by the bellows 7 and the steering casing 3 is arranged in the steering casing 3 .
[0041] In one variant, this sensor 10 for determining a parameter representative of the tightness, with respect to at least gas, of the volume 8 delimited by the bellows 7 and the steering casing 3 can be arranged in the bellows 7 .
[0042] Thus, the or at least one bellows 7, and preferably each bellows 7, may for example be provided with an end portion housing said sensor 10.
[0043] In the example shown, the sensor is an infrared measurement sensor.
[0044] The detection principle is based on the absorption of infrared radiation by the filling gas. Other measurement principles may be used and chemical sensors or sensors incorporating semiconductors may be utilized for such measurements. Such sensors are well known to those skilled in the art and will not be described in detail.
[0045] The filling gas may be a gas already present in the ambient air or it may be a so-called neutral or noble gas, for example argon or others.
[0046] The data from the sensors can be processed in a wide variety of ways. These data from the sensors may, for example, be communicated to a remote terminal where said data is displayed for use during maintenance of the steering system.
[0047] In one variant, as shown in FIG. 3, the monitoring device 9 may comprise a device 13 for emitting an audible or luminous warning signal and a control unit 14 .
[0048] The control unit 14 is configured to acquire data provided by the one or more sensors 10 for determining parameters representative of at least the gas-tightness of the closed volume 8, and to control the device 13 for emitting an audible or luminous warning signal in response to said data.
[0049] In practice, the measured value may for example be compared with a stored threshold value and an alarm issued depending on the result of the comparison.
[0050] The control unit 14 is, for example, in the form of an electronic computing system comprising a microprocessor and a working memory. According to a particular embodiment, the control unit may be in the form of a programmable control device.
[0051] In other words, the described functions and steps may be implemented in the form of a computer program or via hardware components (e.g. programmable gate arrays). In particular, the functions and steps executed by the control unit or its modules may be executed by a set of instructions or computer modules implemented in a processor or controller, or by dedicated electronic components or by components of the programmable logic circuit (or field-programmable gate array (FPGA)) type or of the application-specific integrated circuit (ASIC) type. A combination of computer and electronic components is also possible.
[0052] When a unit or a means or a module of said unit is specified to be configured to perform a given operation, this means that the unit comprises computer instructions and corresponding execution means capable of performing said operation and / or that the unit comprises corresponding electronic components.
[0053] A method for controlling such a steering system 1 therefore comprises at least one step of determining a parameter representative of the tightness, at least with respect to gas, of the closed volume 8 bounded by the bellows 7 and the steering casing 3.
[0054] This step is preceded by a step of at least partially filling the volume 8 with at least one filling gas, and the step of determining a parameter representative of at least the gas-tightness of the closed volume 8 bounded by the bellows 7 and the steering casing 3 is a step of determining the presence or gas concentration of said filling gas inside the closed volume 8.
[0055] The step of determining the presence or concentration of filling gas may be followed by a step of acquiring by the control unit 14 data provided by the sensor 10 for determining parameters representative of at least the gas-tightness of the closed volume 8, and a step of controlling the device 13 for emitting an audible or luminous warning signal in response to said data.
Claims
1. A steering system (1) for a wheeled machine having at least two steered wheels, said steering system (1) comprising: a rack (2); a steering casing (3) arranged around said rack (2); at least one member (4) for driving said axial sliding movement of said rack (2) inside said steering casing (3); two steering connecting rods (5) having one end connected to an end of said rack (2) by an articulated joint (6) and an opposite end connectable to one of said steered wheels of said machine; and two connecting rods (5) each protecting said articulated joint (6) and each connecting rod (5) to said steering a steering system (1) comprising two bellows (7) connected to a casing (3), the two bellows (7) defining a closed volume (8) such that the bellows (7) and the steering casing (3) are tight at least against the outside air, characterized in that the steering system (1) comprises a monitoring device (9) comprising at least one sensor (10) for determining a parameter representative of the tightness, at least against gas, of the closed volume (8) defined by the bellows (7) and the steering casing (3).
2. 2. A steering system (1) according to claim 1, characterized in that the closed volume (8) delimited by the bellows (7) and the steering casing (3) is at least partially pre-filled with a gas, called fill gas, and that the or at least one of the sensors (10) for determining a parameter representative of the tightness of the closed volume (8) delimited by the bellows (7) and the steering casing (3) against at least gas is a sensor for determining the presence or the gas concentration of the fill gas inside the closed volume (8).
3. 3. The steering system (1) according to claim 2, characterized in that for the at least partial pre-filling of the volume (8) delimited by the bellows (7) and the steering casing (3) with a filling gas, the steering system (1) comprises at least one closable gas intake orifice (11) communicating with the volume (8), the gas intake orifice (11) being in a closed state when the volume (8) is in the pre-filled state.
4. 2. A steering system (1) according to claim 1, characterized in that the or at least one sensor (10) for determining a parameter representative of the tightness against at least gas of the closed volume (8) delimited by the bellows (7) and the steering casing (3) is arranged in the steering casing (3).
5. 2. A steering system (1) according to claim 1, characterized in that the or at least one of the sensors (10) for determining a parameter representative of the tightness against at least gas of the closed volume (8) delimited by the bellows (7) and the steering casing (3) is an infrared measurement sensor.
6. 2. A steering system (1) according to claim 1, characterized in that the monitoring device (9) comprises a device (13) for emitting an audible or luminous warning signal and a control unit (14), the control unit (14) being configured to acquire data provided by the at least one sensor for determining a parameter representative of the tightness of the closed volume (8) against at least gas, and to control the device (13) for emitting an audible or luminous warning signal depending on the data.
7. 2. A steering system (1) according to claim 1, characterized in that the member (4) for impelling the axial sliding movement of the rack (2) inside the steering casing (3) is a rotating member meshingly engaged with the rack (2), and the steering system (1) comprises at least one member (15) for rotationally driving the member (4) for impelling the axial sliding movement of the rack (2) inside the steering casing (3).
8. A method for controlling a steering system (1) for a wheeled machine having at least two steered wheels, said steering system (1) comprising a rack (2), a steering casing (3) arranged around said rack (2), a member (4) for driving said axial sliding movement of said rack (2) inside said steering casing (3), two steering connecting rods (5) each having one end connected to an end of said rack (2) by an articulated joint (6) and an opposite end connectable to one of said steered wheels of said machine, said connecting rods (5) each protecting said articulated joint (6) and supporting said articulated joint (6).
1. A method for providing a steering system comprising two bellows (7), each connecting a connecting rod (5) to the steering casing (3), the bellows (7) and the steering casing (3) defining a closed volume (8) that is airtight at least against the outside air, the steering system (1) being as defined in claim 1, characterized in that the method comprises at least one step of determining a parameter representative of the airtightness of the closed volume (8) defined by the bellows (7) and the steering casing (3), at least against gas.
9. 9. The control method according to claim 8, characterized in that prior to the step of determining the parameter representative of the tightness, at least to gas, of the closed volume delimited by the bellows (7) and the steering casing (3), the method comprises a step of at least partially pre-filling the volume (8) with at least one filling gas, and the step of determining the parameter representative of the tightness, at least to gas, of the closed volume (8) delimited by the bellows (7) and the steering casing (3) is a step of determining the presence or the gas concentration of the filling gas inside the closed volume (8).
10. 9. The control method according to claim 8, characterized in that the monitoring device (9) comprises a device (13) for emitting an audible or luminous warning signal and a control unit (14), the method comprising the steps of acquiring by the control unit (14) data provided by the sensor (10) for determining a parameter representative of the tightness of the closed volume (8) against at least gas, and controlling the device (13) for emitting an audible or luminous warning signal in response to the data.