DE102020213399A1 - Shaft arrangement, steering system and method - Google Patents

Abstract

The invention relates to a shaft arrangement (10, 10a) comprising a first shaft which is rotatably mounted in a housing (6); a second shaft rotatably supported in the housing (6), and a torsion bar (3) positioned between and connecting the first shaft and the second shaft and equipped to cause rotational movement of the first shaft and the second To allow shaft relative to each other, wherein the shaft arrangement (10, 10a) has a cover (20, 20a) for sealing arrangement on the housing (6), and wherein the cover (20, 20a) has a through opening for the passage of the first shaft , and wherein a sensor unit is provided and the sensor unit is arranged within the cover (20,20a).
Furthermore, the invention relates to a steering system, a vehicle and a method.

Description

technical field

The invention relates to a shaft arrangement comprising a first shaft which is rotatably mounted in a housing; a second shaft rotatably supported in the housing and a torsion bar positioned between and connecting the first shaft and the second shaft and equipped to permit rotational movement of the first shaft and the second shaft relative to one another, wherein the shaft assembly has a cover for sealing arrangement on the housing, and wherein the cover has a through opening for the passage of the first shaft. Furthermore, the invention relates to a steering system, a vehicle and a method.

Technical background

In motor vehicles, steering systems are used, among other things, which support a driver during various steering maneuvers. Such steering systems usually include several shafts that are arranged differently from each other. The shafts can be input shafts/pinion shafts or shafts of a transmission unit. Usually, the shafts are twisted relative to each other and a torque is determined. Such steering systems are known.

the DE 10 201 111 1846 A1 discloses a device and a method for determining a torque and a steering angle, the torque being able to be applied to a shaft, the shaft having a first and a second shaft section, the first and the second shaft section being rotatable relative to one another, with the first shaft section being at least one first means for generating a first magnetic field is arranged, wherein the device comprises a first sensor and at least one additional sensor for detecting a magnetic field, wherein the first sensor has a first detection area and the at least one additional sensor has an additional detection area, wherein by means of the at least part of the first magnetic field can be detected by the first and the at least one further sensor if the first and the second shaft section are twisted relative to one another, with at least one means for generating a further magnetic field, whereby at least a part of the further magnetic field or a magnetic field resulting from a superimposition of at least a part of the first and at least a part of the further magnetic field can be detected by means of the first and the at least one further sensor, whereby depending on either the the steering angle detected by the first sensor or the magnetic field detected by the at least one additional sensor, and the torque can be determined as a function of the magnetic field detected by the first sensor and the magnetic field detected by the at least one additional sensor.

the EP 2718171 B1 discloses a steering system in a vehicle with an input shaft for transmitting a steering angle specified by the driver and an electric servomotor for generating an assisting drive torque, the servomotor being coupled to the input shaft. The input shaft and the servomotor are accommodated in a common bearing housing, with the input shaft and/or the motor shaft being accommodated in at least one adjustable eccentric bearing.

Disclosure of Invention

In the area of such steering systems, shaft arrangements are sought which are particularly inexpensive and easy to manufacture.

The invention is therefore based on the object of specifying an improved shaft arrangement which is inexpensive and easy to manufacture. Further objects are the specification of a method for determining a torque of such an input shaft, a steering system and a vehicle.

The object is achieved by a shaft arrangement according to claim 1 and by a method, a steering system and a vehicle according to the independent claims.

Advantageous training and developments, which can be used individually or in combination with one another, are the subject matter of the dependent subclaims.

The object is achieved by a shaft assembly comprising a first shaft rotatably mounted in a housing, a second shaft rotatably mounted in the housing, and a torsion bar positioned between and connecting the first shaft and the second shaft . The torsion bar is equipped to allow rotational movement of the first shaft and the second shaft relative to one another, the shaft assembly having a cover for sealing arrangement on the housing, the cover having a through hole for the passage of the first shaft, and wherein a Sensor unit is provided, and wherein the sensor unit is arranged within the lid.

Shafts can be, for example, a pinion shaft/input shaft of a steering system or shafts of a gearbox.

The sensor unit can also include several sensors that are not necessarily dependent on one another. For example, the sensor unit can include a Hall sensor, a steering torque sensor or a torque sensor or a combination of the aforementioned sensors. In particular, the sensor unit can be designed to determine the strength and the direction of the torque acting on the first shaft.

The cover is arranged in particular on the upper side of the housing and is used to seal the housing. 'Inside the lid' can also be understood as 'in the lid'.

The invention avoids the sensor being arranged in the interior space between the housing and the cover. Such an arrangement requires various seals such as a shaft seal ring and a sliding ring, as in the 1 will be described in more detail. By integrating a sensor unit into the cover, the shaft sealing ring and sliding ring components can be dispensed with, which saves costs. Furthermore, the installation of the sensor unit into the cover can be carried out before the assembly of the shaft arrangement, so that a quicker and easier assembly is made possible.

Furthermore, when using a transmission of the signals generated by the sensor unit by means of a cable, there is no need for a cable bushing through the housing.

In one configuration, a torque can be applied to the shaft arrangement and the sensor unit is configured to determine the torque. In this case, the torque is applied, for example by means of a steering wheel, to a pinion shaft/input shaft arrangement, for example. In this case, the torque can be a so-called manual torque or steering torque, which is exerted by a driver on the steering wheel.

In a further refinement, the sensor unit has at least one torque sensor. For this purpose, the sensor unit can be an inductive, capacitive, optical or magnetic sensor, for example a Hall sensor, or a combination thereof. In particular, the torque sensors can generally have a characteristic that is as linear as possible in a predetermined rotational angle range for determining the torque as precisely as possible.

In a further embodiment, the first shaft is designed as an input shaft and the second shaft as a pinion shaft. These are preferably arranged in a steering system of a vehicle. The pinion shaft is arranged between the torsion bar and a steering pinion, with the steering pinion representing a mechanical coupling of a steering column to a rack of the steering system. The torque sensor detects, for example, the relative torsion between the input shaft and the pinion shaft applied by the steering wheel via the torsion bar and determines the torque as a signal. The higher the torsion, the higher the torque.

In a further embodiment, the cover is designed to hold a liquid. This means that the lid has a sealed interior space into which liquid can be introduced. For this purpose, the cover is sealed or has a conventional seal. In a further embodiment, a liquid is arranged in the cover.

In particular, this liquid comprises a ferrofluid or is designed entirely as a ferrofluid. Ferrofluids are liquids that respond to magnetic fields without solidifying. These have magnetizable particles. As a result, a sensor unit sensitive to magnetic fields, in particular a Hall sensor, can be used in an improved manner.

Cables can also be provided. The sensor unit can thus generate electrical signals, which can be guided through the cover by means of the cable through a sealed cable bushing in the cover. In this context, 'tight' means, in particular, sealed. The electrical signals can be used to control power steering/assisted steering.

In a further embodiment, a cable grommet can be provided in the cover. In particular, the cable or cables are passed through the cover by means of the cable grommet. Such a cable grommet is also referred to as a cable outlet and is part of a cable guide. The grommet can be made of neoprene or EPDM (ethylene propylene diene monomer rubber). Such a grommet provides a sufficient seal against the liquid flowing out.

Alternatively or additionally, a plug connector, for example a socket, is provided tightly in the cover, by means of which electrical signals generated by the sensor unit can be passed through the cover. In this context, 'tightly in the cover' means that the connector is arranged in a sealed manner in the cover. Using this connector, the signals can be traced using cables be guided outside. As a result, the signals can be routed safely to the outside without leaking liquid.

Alternatively or additionally, the sensor unit generates electrical signals, with the sensor unit being designed to transmit the signals without contact. 'Contactless' also means wireless, for example by means of a radio link. Thus, a simple transmission is possible.

Furthermore, the object is achieved by a steering system with a shaft arrangement as described above with a sensor evaluation unit for evaluating the electrical signals generated by the sensor unit. The electrical signals generated are evaluated in the sensor evaluation unit and can, for example, be fed to the control unit to generate steering assistance (power steering).

The object is also achieved with a vehicle having a steering system as described above. The vehicle can be a passenger car, an agricultural vehicle, a motorcycle, etc. Vehicles on water and air can also be meant.

• - Aufbringen des Drehmoments auf eine Wellenanordnung, wobei die Wellenanordnung eine Eingangswelle, die in einem Gehäuse drehbar gelagert ist; sowie eine Ritzelwelle, die in dem Gehäuse drehbar gelagert ist, aufweist;
• - Drehbewegung eines Torsionsstabs, der zwischen der Eingangswelle und der Ritzelwelle positioniert ist und diese verbindet und der ausgerüstet ist, um die Drehbewegung der Eingangswelle und der Ritzelwelle relativ zueinander zu erlauben;
• - Messen des Drehmoments mittels einer in einem Deckel angeordneten Sensoreinheit, wobei der Deckel zur abdichtenden Anordnung an dem Gehäuse vorgesehen ist, und wobei der Deckel eine Durchgangsöffnung für den Durchtritt der Eingangswelle aufweist.

Die Vorteile der Wellenanordnung und des Lenksystems können auch auf das Verfahren übertragen werden.Furthermore, the object is achieved by a method for determining a torque with the steps:

• - Applying the torque to a shaft assembly, wherein the shaft assembly includes an input shaft rotatably mounted in a housing; and a pinion shaft rotatably supported in the housing;
• - rotational movement of a torsion bar positioned between and connecting the input shaft and the pinion shaft and equipped to allow rotational movement of the input shaft and the pinion shaft relative to each other;
• - Measuring the torque by means of a sensor unit arranged in a cover, the cover being provided for sealing arrangement on the housing, and the cover having a through-opening for the passage of the input shaft.

The advantages of the shaft arrangement and the steering system can also be transferred to the method.

character list

• 1: eine Wellenanordnung in Frontansicht gemäß dem Stand der Technik;
• 2: eine Wellenanordnung im Querschnitt gemäß dem Stand der Technik;
• 3: eine Wellenanordnung in einer ersten Ausgestaltung im Querschnitt gemäß der Erfindung schematisch;
• 4: eine Wellenanordnung in einer zweiten Ausgestaltung in Frontansicht gemäß der Erfindung schematisch;
• 5: die Wellenanordnung mit Endanschlägen gemäß der Erfindung schematisch;
• 6: die Wellenanordnung mit Statorring gemäß der Erfindung schematisch.

Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. Show it:

• 1 1: a shaft arrangement in front view according to the prior art;
• 2 1: a cross-section of a shaft arrangement according to the prior art;
• 3 1: a shaft arrangement in a first embodiment in cross section according to the invention schematically;
• 4 1: a shaft arrangement in a second embodiment in front view according to the invention schematically;
• 5 : the shaft arrangement with end stops according to the invention schematically;
• 6 : the shaft arrangement with stator ring according to the invention schematically.

Description of Embodiments

1 shows a shaft assembly 100 according to the prior art. Such a shaft assembly 100 includes an input shaft 101 and a pinion shaft 102. The input shaft 101 is connected to a steering wheel (not shown). The shaft assembly 100 is used to change the center of rotation of the wheels to steer the vehicle in the desired direction. The pinion shaft 102 and the input shaft 101 are connected via a torsion bar 103 ( 2 ) connected to each other in a torsionally flexible manner. Further, the prior art shaft assembly 100 includes a housing 106 ( 2 ) which is stationary with respect to the shaft arrangement 100 . The input shaft 101 and the pinion shaft 102 are housed in the housing 106 ( 2 ) arranged. The pinion shaft 102 has a stator with a stator ring 104, the stator ring 104 having fingers 105 protruding in the axial direction A. The fingers 105 are evenly distributed over at least part of the stator ring 104 . The input shaft 101 can be associated with a multipolar magnetic ring (not shown), which generates a first magnetic field. The multipolar magnet ring (not shown) can be assigned to the fingers 105 .

On the housing 106 ( 2 ) is a cover 110 ( 2 ) arranged with a through hole for the passage of the input shaft 101.

The housing 106 ( 2 ) can serve to shield electromagnetic fields, in particular those that are on the cover 110 ( 2 ) works. The housing 106 ( 2 ) can be made of a metal material, for example. Furthermore, the lid 106 ( 2 ) also act against the entry of pollution.

In one of the housing 106 ( 2 ) and the cover 110 ( 2 ) formed space, ie below the lid 110 ( 2 ), is a sensor 107 ( 2 ) Arranged, in particular a torque sensor for detecting the torque. This can be designed as a Hall sensor, for example. This measures the torque when the input shaft 101 and the pinion shaft 102 are twisted relative to one another.

Furthermore, below the cover 110 ( 2 ) for sealing a shaft sealing ring 108 ( 2 ) which prevents dust or water from entering the housing 106 ( 2 ) penetrate. The shaft sealing ring 108 ( 2 ) with a surface extending in the axial direction A on the input shaft 101. Furthermore, as a separate element, a slide ring 111 ( 2 ) below the lid 110 ( 2 ) arranged. Further sealing elements such as a scraper ring etc. can be provided. Furthermore, the shaft sealing ring 108 ( 2 ) also have the wiper ring.

A dust cap 112 ( 2 ) be provided to seal the cover 110 ( 2 ) and the housing 106 ( 2 ) against dust.

Furthermore, both the cover 110 ( 2 ) as well as the dust cap 112 ( 2 ) a sealed passage opening for the passage of the input shaft 101.

2 shows such a shaft assembly 100 according to the prior art with housing 106, sensor 107, shaft seal 108, cover 110, sliding ring 111 and dust cap 112 in detail.

3 Figure 1 shows a shaft assembly 10 according to the invention. This also includes an input shaft 1 and a pinion shaft 2, which are identical to the input shaft 102 ( 2 ) and the pinion shaft 102 ( 2 ) may be in the state of the art.

Further, the shaft assembly 10 includes a torsion bar 3 positioned between and connecting the input shaft 1 and the pinion shaft 2 and equipped to allow rotational movement of the input shaft 1 and the pinion shaft 2 relative to each other. Furthermore, the shaft arrangement 10 has a housing 6, which is also arranged in a rotationally fixed manner. The input shaft 1 and the pinion shaft 2 are rotatably mounted in the housing 6 . The pinion shaft 2 has a stator with a stator ring 4 ( 6 ) with the stator ring 4 ( 6 ) in the axial direction A protruding fingers 5 ( 6 ) having. The fingers 5 ( 6 ) are preferably uniform over at least part of the stator ring 4 ( 6 ) distributed. The stator ring 4 ( 6 ) with his fingers 5 ( 6 ) can be identical to the stator ring 104 ( 2 ) and the fingers 105 ( 2 ) be in the state of the art.

Furthermore, the shaft arrangement 10 has a cover 20 which is arranged above the housing 6 in order to seal it. The cover 20 has a cover interior 21 . Furthermore, the cover 20 has a sealed through-opening for at least the input shaft 1 to pass through.

Furthermore, the shaft arrangement 10 has a sensor 7 which is arranged in the interior space 21 of the cover. The sensor 7 can be identical to the sensor 107 ( 2 ) be. The sensor 7 is also configured to determine a torque applied to the shaft assembly 10 .

In particular, the cover 20 can be made of steel. This is particularly well suited to shielding against environmental influences such as electromagnetic fields.

The signals generated by the sensor 7 can be led out of the cover 20 using cables.

Due to the arrangement of the sensor 7 within the cover 20, these cables can be led out directly from the cover 20, for example by means of a cable grommet or a connector. Leading out through the housing 6 can thereby be dispensed with. Since the cover 20 is already designed as a sealing area, an additional sealing ring such as the shaft sealing ring 108 ( 2 ) can be dispensed with in the prior art. As a result, not only the provision of such a shaft sealing ring 108 ( 2 ), but also on the storage and assembly of such a shaft seal 108 ( 2 ) is eliminated, saving time and money. Greater precision is also achieved as a result, since tolerances with regard to the shaft sealing ring 108 ( 2 ) cannot be complied with. The provision of a feedthrough through the housing 6 can also be dispensed with.

Furthermore, the arrangement of the sensor 7 on the provision, storage and assembly of a slide ring 111 ( 2 ) as in the prior art. This also saves time and money.

The shaft assembly 10 may also include a dust cap, which is not shown here.

4 shows a further embodiment of a shaft arrangement 10a according to the invention. This has the input shaft 1 and the pinion shaft 2 .

Further, the shaft assembly 10a includes the torsion bar 3 and the housing 6. The input shaft 1 and the pinion shaft 2 are in the housing 6 pivoted. The pinion shaft 2 has the stator with the stator ring 4 ( 6 ) with the stator ring 4 ( 6 ) in the axial direction A protruding fingers 5 ( 6 ) having. Furthermore, the shaft arrangement 10a has a cover 20a, which is arranged above the housing 6 in order to seal it. The cover 20a has a cover interior 21 . Furthermore, the cover 20a has the sealed through hole for at least the input shaft 1 to pass through.

Furthermore, the shaft arrangement 10a has a sensor 7 which is arranged in the interior space 21 of the cover. The sensor 7 is also configured to determine a torque applied to the shaft assembly 10a.

A ferrofluid is arranged as a liquid in the cover 20a. This is a liquid that responds to magnetic fields without solidifying and has magnetizable particles. This allows environmental influences such as electromagnetic fields to be shielded. In addition, undesired interactions with the electronic components used in the housing 6 are avoided.

In particular, the liquid results in a particularly good seal, the liquid seal. A particularly reliable sealing results with such a liquid seal.

The signals generated by the sensor 7 can in turn be led out of the cover 20a using cables.

Due to the arrangement of the sensor 7 within the cover 20a, these cables can be led out directly from the cover 20a. Leading out through the housing 6 can thereby be dispensed with. Since the cover 20a is already designed as a sealing area, an additional sealing ring such as the shaft sealing ring 108 ( 2 ) can be dispensed with in the prior art. As a result, not only the provision of such a shaft sealing ring 108 ( 2 ), but also on the storage and assembly of such a shaft seal 108 ( 2 ) is eliminated, saving time and money. Greater precision is also achieved as a result, since tolerances with regard to the shaft sealing ring 108 ( 2 ) cannot be complied with. The provision of a feedthrough through the housing 6 can also be dispensed with.

Furthermore, the arrangement of the sensor 7 dispenses with the provision, storage and assembly of a slide ring 111 as in the prior art. This also saves time and money.

The shaft assembly 10a can also have a dust cap, which is not shown here.

5 shows the shaft assembly 10, 10a with end stops 15 according to the invention schematically.

6 shows the shaft arrangement 10, 10a with the stator ring 4 and the fingers 5 according to the invention schematically.

Furthermore, the sensor 7 can also be designed as a contactless sensor, which generates electrical signals and transmits them without contact.

Reference List

100

a shaft arrangement according to the prior art

101

State of the art input shaft

102

Pinion shaft according to the state of the art

103

State of the art torsion bar

104

Stator ring according to the prior art

105

Prior art fingers

106

State of the art housing

107

State of the art sensor

108

State-of-the-art oil seal

110

State of the art cover

111

State-of-the-art sliding ring

112

Prior art dust cap

10, 10a

a wave arrangement

1

Input shaft according to the invention

2

Pinion shaft according to the invention

3

Torsion bar according to the invention

4

Stator ring according to the invention

5

Fingers according to the invention

6

Housing according to the invention

7

Sensor according to the invention

15

End stops according to the invention

20:20a

Lid according to the invention

21

Lid interior according to the invention

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102011111846 A1 [0003]
• EP 2718171 B1 [0004]

Claims (15)

Shaft assembly (10, 10a) comprising a first shaft rotatably mounted in a housing (6); a second shaft rotatably supported in the housing (6), and a torsion bar (3) positioned between and connecting the first shaft and the second shaft and equipped to cause rotational movement of the first shaft and the second To allow shaft relative to each other, wherein the shaft arrangement (10, 10a) has a cover (20, 20a) for sealing arrangement on the housing (6), and wherein the cover (20, 20a) has a through opening for the passage of the first shaft , characterized in that a sensor unit is provided and the sensor unit is arranged inside the cover (20, 20a). Shaft arrangement (10, 10a) after claim 1 , characterized in that a torque can be applied to the shaft arrangement (10, 10a) and the sensor unit is configured to determine the torque. Shaft arrangement (10, 10a) after claim 1 or 2 , characterized in that the sensor unit has at least one torque sensor. Shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that the first shaft is designed as an input shaft (1) and the second shaft as a pinion shaft (2). Shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that the cover (20, 20a) is designed to hold a liquid. Shaft arrangement (10, 10a) after claim 5 , characterized in that a liquid is arranged in the cover (20, 20a). Shaft arrangement (10, 10a) after claim 6 , characterized in that the liquid comprises a ferrofluid. Shaft arrangement (10, 10a) after claim 6 , characterized in that the liquid is formed entirely as a ferrofluid. Shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that cables are provided and the sensor unit generates electrical signals which can be fed through the cover (20, 20a) through a sealed cable bushing in the cover (20, 20a). . Shaft arrangement (10, 10a) after claim 9 , characterized in that a cable grommet is provided in the cover (20, 20a) and the cable is guided through the cover (20, 20a) by means of the cable grommet. Shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that a connector is provided tightly in the cover (20, 20a) by means of which electrical signals generated by the sensor unit can be passed through the cover (20, 20a). Shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that the sensor unit generates electrical signals and the sensor unit is designed to transmit the signals without contact. Steering system with a shaft arrangement (10, 10a) according to one of the preceding claims, characterized in that a sensor evaluation unit is provided for evaluating the electrical signals generated by the sensor unit. vehicle with a steering system Claim 13 . Method for determining a torque, characterized by the steps: - applying the torque to a shaft arrangement (10, 10a), the shaft arrangement (10, 10a) having an input shaft (1) which is rotatably mounted in a housing (6), and a pinion shaft (2) rotatably supported in the housing (6) (6); - rotational movement of a torsion bar (3) positioned between and connecting the input shaft (1) and the pinion shaft (2) and equipped to allow rotational movement of the input shaft (1) and the pinion shaft (2) relative to each other; - Measuring the torque by means of a sensor unit arranged in a cover (20,20a), the cover (20,20a) being provided for sealing arrangement on the housing (6), and the cover (20,20a) having a through-opening for the Passage of the input shaft (1).

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