Recirculating ball steering

Abstract

The invention relates to a recirculating ball steering device (1) for transmitting a steering movement to a steering swing arm (30), the recirculating ball steering device comprising: a housing (10) having a steering piston (20) arranged in the housing (10), wherein the steering piston (20) comprises a ball screw transmission (27) and is movable along its longitudinal axis; and an electric actuator (40) for supporting the movement of the steering piston (20).

Description

[0001] This application is a divisional application of the invention patent application with application number 201980072344.4, application date October 29, 2019, and invention name “Circulating ball steering device”. Technical Field

[0002] The invention relates to a recirculating ball steering device for a vehicle, in particular a commercial vehicle, for transmitting a steering movement to a steering arm. The invention also relates to a vehicle, in particular a commercial vehicle, comprising a recirculating ball steering device according to the invention. Background Art

[0003] Recirculating ball steering is used in particular in light and heavy commercial vehicles and forms part of a steering gear which, depending on the design, transmits the rotary movement of the steering wheel to the tie rods either directly or indirectly via a connecting rod. A recirculating ball steering is a spindle steering in which the force between the spindle and the nut is transmitted by a ball which circulates in a screw race.

[0004] Such steering gears are already known and are available in a variety of embodiments. For example, documents DE 10 2014 106 488 A1 and DE 10 2014 106 493 A1 describe recirculating ball steering gears in which steering assistance is achieved by using hydraulic pressure.

[0005] However, hydraulic systems have a complex infrastructure and therefore require, in addition to expensive hydraulic pipes, further components such as pumps, hoses or seals. Summary of the invention

[0006] The object of the present invention is therefore to provide a recirculating ball steering system which is improved compared with the prior art, in particular to provide a recirculating ball steering system which has a significantly simplified basic structure.

[0007] This object is achieved according to the invention by a recirculating ball steering system having the features of the invention.

[0008] The recirculating ball steering device according to the invention has a housing with a steering piston arranged in the housing, wherein the steering piston comprises a ball screw transmission and can be moved along its longitudinal axis. In addition, the recirculating ball steering device according to the invention comprises an electric actuator for supporting the movement of the steering piston.

[0009] According to the present invention, a recirculating ball steering device is used to transmit steering movement to a steering swing arm, and the recirculating ball steering device includes: a housing, the housing has a steering piston arranged in the housing, wherein the steering piston includes a ball screw transmission mechanism and can move along its longitudinal axis; and an electric actuator, for assisting the movement of the steering piston; wherein the ball screw transmission mechanism is a first ball screw transmission mechanism, so as to provide a first point of action, by which the rotational movement is converted into translational movement, and the electric actuator includes a stator and a rotor, the stator is arranged around the steering worm of the first ball screw transmission mechanism and is fixedly connected to the housing, and the rotor is fixedly connected to the steering worm, so as to provide a second point of action, through which the torque is transmitted to the steering worm driven by a rotating drive shaft, wherein the drive shaft is connected to a steering generator.

[0010] A recirculating ball steering device according to the present invention is used to transmit steering movement to a steering swing arm, and the recirculating ball steering device comprises: a housing having a steering piston arranged in the housing, wherein the steering piston comprises a ball screw transmission mechanism and can move along its longitudinal axis; and an electric actuator for assisting the movement of the steering piston; wherein the ball screw transmission mechanism is a first ball screw transmission mechanism in the front area of ​​the recirculating ball steering device, so as to provide a first action point, and utilize the first action point to convert rotational movement into translational movement, wherein the steering worm of the first ball screw transmission mechanism is driven by a rotating drive shaft A drive, the drive shaft is connected to a steering generator, and the steering piston includes a second ball screw transmission mechanism in the rear area of ​​the circulating ball steering device, the electric actuator is arranged inside a housing in the rear area of ​​the circulating ball steering device, the electric actuator includes a stator and a rotor, the stator arranged in the rear area is concentrically arranged around the piston-shaped extension of the steering piston and is fixedly connected to the housing, the rotor is arranged between the piston-shaped extension and the stator to provide a second point of action, through which the torque is transmitted to the steering piston, wherein the rotor forms a second ball screw transmission mechanism with the second ball circulation part and the piston-shaped extension.

[0011] The inventors have recognized that a recirculating ball steering system can be realized without hydraulic components by combining at least one ball screw drive with an electric actuator. The power assistance required for the steering movement is performed purely electrically.

[0012] The installation of the recirculating ball steering system according to the invention is significantly simplified on the user side, since expensive hydraulic systems can thus be dispensed with and a simple plug is sufficient to supply the electric actuator with electrical energy.

[0013] Furthermore, it has been shown that a particularly compact recirculating ball steering system can be realized with this arrangement.

[0014] In a preferred embodiment, the steering piston has a second ball screw drive which is coupled to an electric actuator, in particular in which a nut of the ball screw drive is combined with a rotor of the electric actuator. Since the ball screw drive has a very high efficiency, the combination of the nut and the rotor allows a less powerful electric actuator to be used, which has a particularly favorable effect on the size of the recirculating ball steering.

[0015] In another preferred embodiment, the electric actuator is connected to the steering piston via a force transmission device. The force transmission device allows a spatial separation between the electric actuator and the steering piston, so that the recirculating ball steering can be specifically adapted to the customer's specifications in terms of spatial geometry.

[0016] In a further preferred embodiment variant, the steering piston comprises a second ball screw drive which is coupled to the electric actuator via a force transmission means.

[0017] The force transmission means is preferably selected from the group consisting of a toothed belt drive, a chain drive, a gear drive, a bevel gear drive, a hypoid gear drive, a crown gear drive or a worm gear drive.

[0018] In a particularly preferred embodiment variant, the recirculating ball steering system has no hydraulic unit, so that the movement of the steering piston is supported exclusively electrically.

[0019] According to a further aspect, the invention relates to a vehicle, in particular a commercial vehicle, having a recirculating ball steering system according to the invention.

[0020] Further advantages and features of the device according to the invention are derived from the dependent claims, which relate to advantageous configurations of the invention and are not to be understood as restrictive. The invention also includes a combination of features of different dependent claims, as long as these are technically possible, even if these dependent claims are not related to each other or they belong to different claim categories. This also applies to the individual features of the embodiments discussed below, as long as these features are not considered to be mandatory for a person skilled in the art to belong to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The embodiments described below are provided to further explain the present invention to those skilled in the art. The embodiments are explained with the aid of the accompanying drawings. In the accompanying drawings:

[0022] Figure 1 A cross section of a first embodiment of a recirculating ball steering device according to the present invention;

[0023] Figure 2 A cross section of a second embodiment of a recirculating ball steering device according to the present invention;

[0024] Figure 3 A cross section of a third embodiment of a recirculating ball steering device according to the present invention;

[0025] Figure 3a Figure 3 FIG. 1 is a diagram of a variant implementation according to section AA;

[0026] Figure 4 A cross section of a fourth embodiment of a recirculating ball steering device according to the present invention;

[0027] Figure 4a Figure 4 FIG. 1 is a diagram of a variant implementation according to section AA;

[0028] Figure 5 A cross section of a fifth embodiment of a recirculating ball steering device according to the present invention;

[0029] Figure 6 A cross section of a sixth embodiment of a recirculating ball steering device according to the present invention;

[0030] Figure 6a Show Figure 6 FIG. 1 is a diagram of a variant implementation according to section AA;

[0031] Figure 7 A cross section of a seventh embodiment of a recirculating ball steering device according to the present invention;

[0032] Figure 7a Show Figure 7 FIG. 1 is a diagram of a variant implementation according to section AA;

[0033] Figure 8 A cross section of an eighth embodiment of a recirculating ball steering device according to the present invention;

[0034] Fig. 9 A cross section of a ninth embodiment of a recirculating ball steering device according to the present invention;

[0035] Fig.10 A cross section of a tenth embodiment of a recirculating ball steering device according to the present invention;

[0036] Fig.11 A cross section of an eleventh embodiment of a recirculating ball steering device according to the present invention;

[0037] Fig.12 A cross section of a twelfth embodiment of a recirculating ball steering device according to the present invention;

[0038] Fig.13 A cross section of a thirteenth embodiment of a recirculating ball steering device according to the present invention;

[0039] Fig.13a Fig.13 ; and

[0040] Fig.13b Cross section through a fourteenth embodiment variant of a recirculating ball steering system according to the invention. DETAILED DESCRIPTION

[0041] Figure 1 A first embodiment variant of a recirculating ball steering system 1 according to the invention for transmitting steering movements from a steering wheel (not shown) to a steering arm 30 is shown.

[0042] The recirculating ball steering device 1 has a housing 10 with a steering piston 20 arranged in the housing 10 and movable along a longitudinal axis XX. The steering piston 20 is composed of a plurality of individual components and further comprises a steering nut 21, a steering worm 26 and a ball recirculation unit 27, wherein the steering nut 21, the steering worm 26 and the ball recirculation unit 27 form a first ball screw drive 27 and thus a first point of action, with which a rotational motion is converted into a translational motion.

[0043] The steering nut 21 is arranged in a sliding manner in the housing 10 so that an axial longitudinal displacement of the steering piston 20 can be implemented. The steering nut 21 has a toothed area 22 on the outside, in which the teeth 23 of the steering shaft 24 engage. The steering shaft 24 is connected to the steering lever 30, so that a longitudinal displacement of the steering piston 20 along the longitudinal axis XX causes a rotation of the steering shaft 24 and thus of the steering lever 30. The longitudinal displacement of the steering piston 20 is caused by the driver via a rotating drive shaft 25, which connects a steering generator (not shown), for example a steering wheel, to a steering worm 26.

[0044] In addition, the recirculating ball steering device 1 comprises an electric actuator 40 arranged transversely to the longitudinal axis XX, which can be controlled by a control unit 50. In the present embodiment variant, the electric actuator 40 is implemented as an electric motor, in particular a transverse electric motor, and is arranged in the housing 10. By providing a torque, the electric actuator supports the longitudinal movement of the steering piston 20. To this end, the electric actuator 40 comprises a stator 41 arranged around the steering worm 26 and fixedly connected to the housing 10 and comprises a rotor 42 fixedly connected to the steering worm 26. Therefore, the steering worm 26 has a second point of action, through which the torque can be transmitted to the steering worm 26.

[0045] The electric actuator 40 is controlled by the controller 50 according to the driver's steering command detected by a sensor 80 located on the drive shaft 25, for example, for detecting a rotation angle or a torque, and if necessary according to other vehicle parameters. The electric actuator 40 provides a torque, which supports the rotational movement of the steering worm 26 and thus causes a longitudinal displacement of the steering nut 21 along the longitudinal axis XX, which in turn causes a torsion of the steering shaft 24 and thus causes a torsion of the steering arm 30.

[0046] exist Figure 2 1 shows a second embodiment of the recirculating ball steering device 1 according to the invention. In contrast to the first embodiment, the recirculating ball steering device 1 has a rear region 11 arranged opposite the front region 12. In the front region 12, for example, a drive shaft 25 is arranged, which extends through the housing 10 and can be connected to a steering generator.

[0047] Furthermore, in the present embodiment variant, the steering piston 20 has a piston-like extension 21 a, which includes a second ball screw drive 28 and extends into the rear region 11 of the recirculating ball steering device 1. The steering piston 20 thus has a first ball screw drive 27 in the front region 12 of the recirculating ball steering device 1 and a second ball screw drive 28 in the rear region 11.

[0048] Furthermore, an electric actuator 40 is arranged in the housing 10 in the rear region 11 of the recirculating ball steering device 1, which is designed as an electric motor, in particular as a hollow shaft servomotor, in the present embodiment variant. By providing a torque, the electric actuator supports the longitudinal displacement of the steering piston 20. The stator 41 arranged in the rear region 11 is arranged concentrically around the piston-shaped extension 21a and is fixedly connected to the housing 10. A rotor 42 is arranged between the piston-shaped extension 21a and the stator 41, which forms the second ball screw drive 28 with the second ball recirculation 29 and the piston-shaped extension 21a. Due to this special arrangement, the piston-shaped extension 21a is fully supported in the housing 10, so that an additional support of the piston-shaped extension 21a, for example by means of a ball bearing, is omitted.

[0049] Furthermore, a controller 50 is arranged outside the housing 10 in the rear region 11 .

[0050] The electric actuator 40 is controlled by the control unit 50 and, if necessary, by other vehicle parameters according to the driver's steering command, which is detected by the sensor 80. The electric actuator 40 provides a torque, which is transmitted to the steering piston 20 at the second point of action via the second ball screw drive 28 and supports the longitudinal displacement of the steering piston 20 along the longitudinal axis XX.

[0051] exist Figure 3 and 3a 2 shows a third embodiment variant of a recirculating ball steering system 1 according to the invention for transmitting steering movements from a steering wheel (not shown) to a steering arm 30 .

[0052] The structure of the recirculating ball steering device 1 is basically the same as that of the first embodiment, except that the torque of the electric actuator 40 is transmitted to the steering worm 26 via a force transmission device 60, in particular a toothed belt drive 610. In the current embodiment, the electric actuator 40 is arranged outside the housing 10 and is implemented as an electric motor, in particular as a servomotor.

[0053] The toothed belt transmission 610 includes a transmission wheel 611 and a toothed belt 612 ( Figure 3a The transmission wheel 611 is fixedly connected to the steering worm 26 and therefore has a second point of action, via which the torque of the electric actuator 40 can be transmitted to the steering worm 26. The toothed belt 612 is tensioned via the transmission wheel 611 and the shaft 43 of the electric actuator 40.

[0054] exist Figure 4 and Figure 4a , a fourth embodiment of the recirculating ball steering device 1 according to the present invention is shown, which is substantially identical in structure to the second embodiment, except that the torque of the electric actuator 40 is transmitted to the steering piston 20 via a force transmission device 60, in particular a toothed belt drive 610. In the present embodiment, the electric actuator 40 is arranged outside the housing 10 and is implemented as an electric motor, in particular as a servomotor.

[0055] The toothed belt transmission 610 includes a transmission wheel 611 and a toothed belt 612 ( Figure 4a The transmission wheel 611 is connected to the piston-shaped extension 21a via the transmission nut 21b and thus has a second point of action, via which the torque of the electric actuator 40 can be transmitted to the steering piston 20. The toothed belt 612 is tensioned via the transmission wheel 611 and the shaft 43 of the electric actuator 40.

[0056] The transmission nut 21 b is connected to the housing 10 via a bearing device 70 , for example a ball bearing, so that the steering piston 20 is supported at at least two points spaced apart from one another in the housing 10 and is restricted in radial movement.

[0057] In the present embodiment, the electric actuator 40 and the controller 50 are arranged relative to each other so that the entire recirculating ball steering device 1 is a compact structural unit.

[0058] Alternatively, the electric actuator 40 and the controller 50 may also be arranged relative to each other so that the entire recirculating ball steering device 1 is an elongated structural unit ( Figure 5 ).

[0059] exist Figure 6 and 6a 2 shows a sixth embodiment variant of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the third embodiment variant, except that a chain drive 620 is used as the force transmission device 60 .

[0060] The chain transmission device 620 includes a plurality of sprockets 621, 622, 623 and a chain 624 ( Figure 4a ). The sprocket 621 is fixedly connected to the steering worm 26 and thus has a second action point, through which the torque of the electric actuator 40 can be transmitted to the steering worm 26. Another sprocket 622 is located on the shaft 43 and is fixedly connected thereto. The chain 624 runs on the sprockets 621, 622 and is tensioned by the chain tensioning wheel 623.

[0061] exist Figure 7 and 7a 2 shows a seventh embodiment variant of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the fourth embodiment variant, except that the force transmission device 60 comprises a chain transmission device 620 .

[0062] In the present embodiment variant, the force transmission means 60 is as follows Figure 4 The sprocket 621 is connected to the piston-shaped extension 21a via a transmission nut 21b and thus has a second point of action, through which the torque of the electric actuator 40 can be transmitted to the steering piston 20. Another sprocket 622 is located on the shaft 43 of the electric actuator 40 and is fixedly connected thereto. The chain 624 runs on the sprocket 621 and the sprocket 622 and is tensioned by a chain tensioning wheel 623.

[0063] exist Figure 8 2 shows an eighth embodiment variant of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the third embodiment variant, except that the force transmission device 60 includes a gear transmission device 630 .

[0064] In the present embodiment variant, the force transmission means 60 is as follows Figure 3 As in the embodiment variant of , it is arranged in the front region 12 of the housing 10 and comprises a plurality of gear wheels 631 , 632 , 633 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering worm 26 .

[0065] exist Fig. 9 2 shows a ninth embodiment variant of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the fourth embodiment variant, except that the force transmission device 60 includes a gear transmission device 630 .

[0066] In the present embodiment variant, the force transmission means 60 is as follows Figure 4 As in the embodiment variant of , the steering piston 20 is arranged in the rear region 11 of the housing 10 and comprises a plurality of gear wheels 631 , 632 , 633 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering piston 20 .

[0067] exist Fig.10 2 shows a tenth embodiment variant of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the third embodiment variant, except that the force transmission device 60 includes a bevel gear transmission device 640 .

[0068] In the present embodiment variant, the force transmission means 60 is as follows Figure 3 As in the embodiment variant of , the electric actuator 40 is arranged in the front region 12 of the housing 10 and comprises two gear wheels 641 , 642 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering worm 26 .

[0069] exist Fig.11 , an eleventh embodiment variant of the recirculating ball steering device 1 according to the present invention is shown, which has a substantially identical structure to the fourth embodiment variant, except that the force transmission device 60 comprises a bevel gear transmission device 640 .

[0070] In the present embodiment variant, the force transmission means 60 is as follows Figure 4 As in the embodiment variant of , the steering piston 20 is arranged in the rear region 11 of the housing 10 and comprises two transmission wheels 641 , 642 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering piston 20 .

[0071] exist Fig.12 , a twelfth embodiment variant of the recirculating ball steering device 1 according to the present invention is shown, which has a substantially identical structure to the third embodiment variant, except that the force transmission device 60 comprises a crown gear transmission 650 .

[0072] In the present embodiment variant, the force transmission means 60 is as follows Figure 3 As in the embodiment variant of , the steering worm 26 is arranged in the front region 12 of the housing 10 and comprises two gear wheels 651 , 652 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering worm 26 .

[0073] exist Fig.13 and 13 a shows a thirteenth variation of the recirculating ball steering device 1 according to the present invention, which has a substantially identical structure to the fourth variation, except that the force transmission device 60 includes a worm gear transmission device 650 .

[0074] In the present embodiment variant, the force transmission means 60 is as follows Figure 4 As in the embodiment variant of , the steering piston 20 is arranged in the rear region 11 of the housing 10 and comprises two transmission wheels 661 , 662 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering piston 20 .

[0075] Finally, in Fig.13b , a fourteenth variation of the recirculating ball steering device 1 according to the present invention is shown, which has a substantially identical structure to the third variation, except that the force transmission device 60 comprises a worm gear 660 .

[0076] In the present embodiment variant, the force transmission means 60 is as follows Figure 3 As in the embodiment variant of , it is arranged in the front region 12 of the housing 10 and comprises two gear wheels 661 , 662 which mesh with one another and thus transmit the torque of the electric actuator 40 to the steering worm 26 .

[0077] Reference numerals list

[0078] 1 Recirculating ball steering device

[0079] 10 Housing

[0080] 11 Rear area

[0081] 12 Front area

[0082] 20 Steering piston

[0083] 21 Steering nut

[0084] 21a Piston-shaped extension

[0085] 21b Drive nut

[0086] 22 Tooth area

[0087] 23 teeth

[0088] 24 Steering shaft

[0089] 25 Drive shaft

[0090] 26 Steering worm

[0091] 27 First ball circulation unit

[0092] 27a First ball screw transmission mechanism

[0093] 28 Second ball screw transmission mechanism

[0094] 29 Second ball circulation unit

[0095] 30 Steering arm

[0096] 40 Electric actuator

[0097] 41 Stator

[0098] 42 Rotor

[0099] 43 Axis

[0100] 50 Controller

[0101] 60 Force transmission device

[0102] 70 Support device

[0103] 80 Sensors

[0104] 610 Toothed belt drive

[0105] 611 Transmission wheel

[0106] 612 Toothed belt

[0107] 620 Chain Drive

[0108] 621 Sprocket

[0109] 622 Sprocket

[0110] 623 Chain tensioner

[0111] 624 Chain

[0112] 630 Gear Transmission

[0113] 631 Gear

[0114] 632 Gear

[0115] 633 Gear

[0116] 640 Bevel Gear Transmission

[0117] 641 Transmission wheel

[0118] 642 Transmission wheel

[0119] 650 Crown gear transmission

[0120] 651 Transmission wheel

[0121] 652 Transmission wheel

[0122] 660 Worm gear drive

[0123] 661 Transmission wheel

[0124] 662 Transmission wheel

Claims

1. A recirculating ball steering device (1) for transmitting a steering motion to a steering swing arm (30), the recirculating ball steering device comprising: A housing (10) having a steering piston (20) arranged in the housing, wherein the steering piston (20) comprises a ball screw drive and is movable along its longitudinal axis; and an electric actuator (40) for assisting the movement of the steering piston (20); wherein the ball screw transmission mechanism is a first ball screw transmission mechanism (27) so as to provide a first action point, by means of which the rotational motion is converted into the translational motion, and The electric actuator comprises a stator (41) and a rotor (42), wherein the stator is arranged around a steering worm (26) of a first ball screw transmission mechanism and is fixedly connected to the housing, and the rotor is fixedly connected to the steering worm so as to provide a second point of action, through which the torque is transmitted to the steering worm (26) driven by a rotating drive shaft (25), wherein the drive shaft (25) is connected to a steering generator.

2. The recirculating ball steering device (1) according to claim 1, wherein: The recirculating ball steering system does not include a hydraulic unit, and the movement of the steering piston (20) is supported only electrically.

3. A recirculating ball steering device (1) for transmitting a steering motion to a steering swing arm (30), the recirculating ball steering device comprising: A housing (10) having a steering piston (20) arranged in the housing (10), wherein the steering piston (20) comprises a ball screw drive and is movable along its longitudinal axis; and an electric actuator (40) for assisting the movement of the steering piston (20); wherein the ball screw drive is a first ball screw drive (27) in the front region (12) of the recirculating ball steering device (1) in order to provide a first point of action by means of which a rotational movement is converted into a translational movement, wherein a steering worm (26) of the first ball screw drive is driven by a rotating drive shaft (25) which is connected to a steering generator, and The steering piston includes a second ball screw transmission mechanism (28) in the rear area (11) of the recirculating ball steering device (1), and the electric actuator (40) is arranged inside the housing (10) of the rear area (11) of the recirculating ball steering device (1). The electric actuator includes a stator (41) and a rotor (42). The stator arranged in the rear area (11) is concentrically arranged around the piston-shaped extension (21a) of the steering piston (20) and is fixedly connected to the housing (10). The rotor (42) is arranged between the piston-shaped extension (21a) and the stator (41) to provide a second point of action, through which the torque is transmitted to the steering piston (20), wherein the rotor (42) forms a second ball screw transmission mechanism (28) with the second ball circulation part (29) and the piston-shaped extension (21a).

4. The recirculating ball steering device (1) according to claim 3, wherein: The recirculating ball steering system does not include a hydraulic unit, and the movement of the steering piston (20) is supported only electrically.

5. A vehicle having a recirculating ball steering device (1) according to any one of claims 1 to 4.

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