EP3010783A1

EP3010783A1 - Double-pinion steering mechanism having a hollow shaft motor

Info

Publication number: EP3010783A1
Application number: EP14729670.1A
Authority: EP
Inventors: Aksel Maier; Anatoli Schröder; Christine GOLDBERG; Kai Vohwinkel
Original assignee: ThyssenKrupp Presta AG
Current assignee: ThyssenKrupp Presta AG
Priority date: 2013-06-21
Filing date: 2014-06-13
Publication date: 2016-04-27
Also published as: DE102013010362B4; CN105324293B; CN105324293A; WO2014202472A1; US20160207565A1; DE102013010362A1

Abstract

The invention relates to a steering mechanism, in particular for motor vehicles, having a steering housing (41), in which a steering rack (40) is mounted in a longitudinally displaceable manner and is connected to steerable wheels in order to pivot same, wherein the steering rack (40) is provided with a first toothed segment (38), which meshes with a first pinion (37) of a pinion shaft (6), and wherein the pinion shaft (6) is connected to a steering wheel indirectly by means of a steering shaft, wherein the steering rack (40) has a second toothed segment (39), which is opposite the first toothed segment (38) in relation to the longitudinal axis of the steering rack (40), and a second pinion (36) is provided, which is engaged with the second toothed segment (38), wherein an electric motor is provided, which indirectly drives the first pinion (37), which is mechanically coupled in a restricted manner to the second pinion (36) for rotation in the opposite direction, and wherein the electric motor is formed as a hollow shaft motor (1), which partially surrounds the input shaft (4) and/or the pinion shaft (6).

Description

Double pinion steering gear with hollow shaft motor

The present invention relates to a steering gear for motor vehicles having the features of the preamble of claim 1.

For large and heavy vehicles of the so-called middle class, the

Luxury class and for off-road vehicles, a design of electrically assisted steering gear for motor vehicles is preferred in which the

Supporting force via a second toothing in the rack

is initiated. There are known steering gear in which the servo drive acts on the rack via a second steering pinion and a second toothing. Such steering gears are shown in the published patent applications DE 10 2005 022 867 AI, DE 10 2007 004 218 AI and WO 2006/138209 A2. These steering gears have a relatively large volume of construction, since the servo drive is provided separately next to the engagement steering pinion / rack. In addition, the leadership of the rack in the area of the steering pinion on a

Pressure piece to be kept free of play. This storage is with

Associated production costs and represents a possible in practice

Noise source that is undesirable.

From DE 10 2010 027 553 Al a double-pinion steering gear is known in which the two steering pinions are arranged opposite to the rack at an angle of 90 ° to the rack. The two steering pinions are thereby forcibly mechanically coupled to an opposite rotation by means of spur gears or bevel gears. Due to the geometric arrangement of the pinion to each other, the elimination of a complex pressure piece in the previously known form is made possible. At least one steering pinion is with a

Servomotor coupled, which supports the steering. The rotation of the steering shaft is detected by a sensor. The disadvantage of the arrangement is that it is due to the location of the servo drive and the sensor too

Space bottlenecks comes.

It is therefore an object of the present invention to provide a steering gear that has compact dimensions and yet provides the necessary for heavy vehicles steering auxiliary power available.

This object is achieved by a steering gear having the features of claim 1.

Thereafter, a steering gear, in particular for motor vehicles, with a steering housing, in which a rack is longitudinally displaceable and connected for pivoting steerable wheels with these, wherein the rack is provided with a first toothed segment, which meshes with a first pinion of a pinion shaft and the pinion shaft is indirectly connected to a steering wheel via a steering shaft, the rack having a second sector gear opposite to the first sector gear relative to the longitudinal axis of the rack, and a second pinion engaging with the second sector gear an electric motor is provided which indirectly drives the first pinion mechanically positively coupled to the second pinion to counter-rotation, in which the electric motor is designed as a hollow shaft motor, the input shaft and / or the pinion shaft at least in a portion of one of these waves partially surrounds. By this arrangement, a particularly compact design is possible. This is especially true when the hollow shaft of the electric motor is arranged coaxially with the input shaft.

Preferably, the hollow shaft motor drives a gear shaft, which is connected via a gear to the pinion shaft. In one embodiment, a rotation angle sensor on the input shaft and a rotation angle sensor on the pinion shaft are provided, so that the applied steering wheel torque and the position of the rotor can be determined.

Preferably, the transmission is a reduction gear. The motor can thus be designed compactly with high speed and low torque.

Furthermore, it is preferably provided that the first and the second pinion are arranged obliquely opposite the rack, wherein the plane which the sprockets span the longitudinal axis of the rack under a

Inclination angle less than 90 ° intersects. The oblique arrangement space can be saved in the pinion.

It is advantageous if the mechanical coupling of the two pinions takes place via gears.

Moreover, it is advantageous if the axes of rotation of the two opposing pinions are arranged at an acute angle to each other. Thus, the engagement pinion / rack can be adjusted without pressure piece.

It is preferably provided that the toothed segments are arranged in mutually inclined planes, in correspondence with the pinion arranged at an acute angle to each other.

In the inventive embodiment, the remote drive bearing of the second pinion advantageously has a bearing assembly for adjusting the play of the mesh pinion / rack.

A particularly simple arrangement results, however, if the axes of rotation of the two opposing pinion are arranged parallel to each other, since then the gear coupling these gear elements may be formed, for example, as spur gears.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. Show it : 1 shows a longitudinal section through an inventive steering gear with double pinion arrangement and hollow shaft motor,

2 shows a side view of the input shaft in conjunction with the pinion shaft and a longitudinal section and two cross sections of the arrangement,

3: a spatial representation of the rotation angle sensors and

Encoder magnets on the input shaft in a preassembled state,

4 shows a longitudinal section of the transmission of Figure 1,

Fig. 5 is a perspective view of the transmission of Figure 4, as well

Fig. 6: a longitudinal section of the pinion / rack engagement.

1 shows a hollow shaft motor 1 lying in a motor housing 2 is shown as a servo drive of a steering gear. The hollow shaft motor 1 surrounds a centered in the housing 2 with a longitudinal axis 3 lying input shaft 4, which is rotatably connected to the steering shaft, not shown here, connected to the steering wheel. A circular cylindrical torsion bar 5 connects on the one hand the input shaft 4 with a pinion shaft 6 in the axial direction, so that they have a defined position to each other. On the other hand, depending on the steering wheel torque, the torsion bar 5 causes a relative rotation between the input shaft 4 and the pinion shaft 6, which is used to control the steering assist and its direction. As shown in FIG. 2, the torsion bar 5 is pressed at one end into a round centered bore 7 of the pinion shaft 6. At the other end it is connected to the input shaft 4, in which it passes through the input shaft 4 centered over the entire length and both are pierced transversely at the end and verstifted. The torsion bar 5 is tapered in a central portion. The input shaft 4 has for receiving the torsion bar 5 and the pinion shaft 6 a

passing through central recess 8 with three paragraphs 9, 10, 11. At the pinion remote end in the region of the taper of the torsion bar 5, the

Recess 8 on the first paragraph 9. Until the pinion end, the recess 8 is circular cylindrical. The second paragraph 10 of the recess 8 serves as a collar for the pinion shaft 6 and is at the end of the taper of the Torsion bar 5 is arranged. In the area of the second paragraph 10 are the

Recess 8, and the pinion shaft 6 received therein with play designed oval cylinder. The pinion shaft 6 can thus in the

oval cylindrical recess 8 are rotated by a certain angular range until a stop serves as a mechanical entrainment. This limitation represents a protection of the torsion bar 5. At the second paragraph 10 includes the third paragraph 11, in which the recess 8 again

is formed circular cylindrical and also the pinion shaft 6 a

having circular cross-section. The input shaft 4 surrounds the pinion shaft 6 with little play, with needle bearings 12 on the pinion shaft 6 ensure that the input shaft 4 is rotatably mounted about the pinion shaft 6. The input shaft 4 has on the outside a first projection 13 and a second projection 14, wherein the first projection 13 is in the region of the first paragraph 9 of the recess 8.

The rotation of the torsion bar 5 is about two magnetic

Rotation angle sensors 15, 16 detected. The rotation angle sensors 15, 16 each have a magnetic ring 17, 18 as a donor magnet and a sensor element 19, 20. Preferably, the transmitter magnets 17, 18 via a

Adhesive connection on the input shaft 4 and the pinion shaft 6 fixed. The sensor element 19, 20 may be a Hall or magnetoresistive sensor

be educated. Furthermore, optical sensors consisting of a light-emitting and a photosensitive component or

Strain gauges conceivable. A first transmitter magnet 17 is disposed on the input shaft 4 in abutment with the annular collar formed by the second projection 14 in front of the pinion shaft 6 and a second

Encoder magnet 18 is arranged on the pinion shaft 6, as shown in Figure 3. The position of the magnetic rings 17, 18 to each other at a

Rotation of the torsion bar 5 results in the known stiffness of the

Torsion bar 5 the steering wheel torque.

The hollow shaft motor 1 comprising the input shaft 4 and pinion shaft 6 has a stator 21, a rotor 22 and a magnet 23. The

Input shaft 4 and the pinion shaft 6 are concentrically surrounded by the rotor 22, wherein between the donor magnets 17, 18 and the Sensor elements 19, 20 are arranged. The rotor 22 is in turn surrounded concentrically by the magnet 23 and the stator 21. In this case, the rotor 22 is realized with a permanent magnet and the fixed stator 21 comprises coils which are driven offset in time by an electronic circuit to give rise to a rotating field, which is a

Torque on the permanently excited rotor 22 causes. The rotor 22 drives a gear 24 via a rotatably connected gear shaft 25 at. Preferably, the rotor 22 is connected to the transmission shaft 25 via a serration

connected.

The transmission shaft 25 is hollow and is penetrated by the pinion shaft 6 with clearance. The gear 24 is coaxial and designed as a cycloidal gear, as shown in Figure 4 and Figure 5. The cycloidal gear 24 has two offset by 180 degrees cams 26, 27, a driving plate 28, driving pins 29, cylindrical pins 30 and an eccentric 31. The eccentric 31 drives the cams 26, 27, which are penetrated by the driving pins 28 and which roll on the stationary cylinder pins 30. The

Mitnehmerstifte 29 are firmly pressed into the drive plate 28 and have in height of the cams 26, 27 a bearing sleeve 32, which allows the drive plate 28 via the cams 26, 27 to drive. Each revolution of the gear shaft 25, the output moves to one

Curve section on the stationary cylinder pins 30 on. Thus, the output speed of the transmission shaft 25 of the transmission 24 is reduced while increasing the torque of the drive plate 28.

The drive plate 28 has, as shown in Figure 1, a concentric bearing seat 33 for a first gear 34. The first gear 34 is rotatably with the drive plate 28 and the penetrating pinion shaft. 6

connected, so that the drive plate 28, the pinion shaft 6 indirectly drives. In addition, the first gear 34 meshes with a second gear 35 which rotatably surrounds a second pinion 36 at an end close to the drive. The pinion shaft 6 has at its end remote from the drive a first pinion 37, which mechanically with the second pinion 36 via the two gears 34, 35 at their drive-near ends to an opposite direction

is positively coupled. Figure 6 shows the pinion 37, 36 and their engagement in the Rack 40 in a detail view. The spaced parallel aligned pinions 37, 36 are oppositely engaged with a respective rack segment 38, 39 on a rack 40, wherein the rack segments 38, 39 are located on the rack 40 with respect to the longitudinal axis. The rack 40 is mounted in a steering housing 41 perpendicular to the longitudinal axis 3 of the input shaft 4.

During assembly, the input shaft 4, the pinion shaft 6 and the motor 1 is inserted into the motor housing 2, wherein a cover 42, the motor housing 2 in the direction of the steering shaft at the height of the first projection 13 of the input shaft 4 closes. The input shaft 4 passes through the cover 42 (see FIG. 1). Furthermore, the input shaft 4 and the rotor 22 are rotatable in

Motor housing 2 supported by corresponding bearings 43. Thereafter, the transmission shaft 25 and the transmission 24 are mounted. Subsequently, the active first gear 34 of the first pinion 37 is mounted on a toothing 44 of the first pinion 37 with fit and rotatably inserted with the outside in the drive plate 28. The passive second gear 35 is brought without clearance in engagement with the active first gear 34 during assembly. For this purpose, the passive second pinion 36 has a serration and in the direction of the drive 1 a short cylindrical shoulder. The passive second gear 35 has an inner diameter which has a clearance fit to the cylindrical shoulder. During assembly, the active gear 34 is placed on the cylindrical part and the passive gear 35 is brought into engagement with the active gear 34 without play. After the play-free position is found, the passive gear 35 is pressed onto the serration, wherein it comes to a positive connection, which is designed so that the resulting moments can be transmitted. Furthermore, the two pinions 37, 36 are brought into engagement with the rack 40 without play before the steering housing 41 is brought into contact with the motor housing 2 in the longitudinal direction and connected by means of fastening means.

The steering housing 41 connected to the motor housing 2 surrounds the

Gear 24 and the two pinions 37, 36, and the rack 40. In the region of the two pinions 37, 36, the steering housing 41 is formed concentrically in the longitudinal direction of the rack center. Towards the transmission 24, this widens Steering housing 41, wherein a first shoulder 45 at the height of the gears 34, 35 and a second shoulder 46 at the height of the transmission 24 is arranged. Due to the azentrische position of the rack 40 with respect to the longitudinal axis 3 of the input shaft 4 and the pinion shaft 6, the steering housing 41 is formed in the region of the transmission 24 is not rotationally symmetrical about the longitudinal axis 3. Therefore, the gear 24 for securing the position in the steering housing 40 an anti-rotation in the form of a nose 47 (see also Figure 5). Of

Furthermore, the pinions 37, 36 are rotatably mounted relative to the steering housing 41 at both ends. Furthermore, the steering housing 41 in

Area of a remote drive bearing 48 of the second pinion 36 a closed with a closure cover 49 opening 50.

The steering housing 41 is preferably made of aluminum or magnesium.

In a further embodiment, the second pinion on the drive distant bearing on a bearing assembly with two sleeves, wherein the outer sleeve forms a guide and the inner sleeve forms a sliding piece. The sliding piece is slidably disposed along inclined guide surfaces, so that when moving the sliding piece, the pinion on the engagement pinion / rack is deliverable. To preload and adjust the game is a spring between the sleeves and that as a set screw

trained closure cap provided.

In another embodiment, it is conceivable that the coaxial transmission is designed as a planetary gear or other eccentric gear or gear reduction.

Furthermore, it is provided in one embodiment that the axes of rotation of the two opposing pinions are arranged at an acute angle to each other and the two rack segments, located on the

Rack relative to the longitudinal axis are opposite, are arranged in mutually inclined planes, because in this way a backlash of the teeth engagement can be achieved by a bias of the rack in the included angle inside. In another embodiment, it is preferably provided that the pinions have an offset to each other in the longitudinal direction of the rack, so that space can be saved with a constant coupling width of the pinion.

If, in the case of the steering gear according to the invention, a steering movement on the steering wheel is detected, the torsion bar detects a rotation of the steering shaft relative to the pinion shaft. The signal thus triggered controls the electric motor which drives the pinion shaft via the gearbox driven by the rotor. The coaxial transmission transmits the reduced output speed of the transmission shaft to the active first pinion. Due to the positive mechanical coupling of the first pinion with the second pinion, the rack is driven from opposite sides to a longitudinal displacement, which causes a pivoting of the steered wheels. The steering assist force generated by the servo motor is thus introduced via two pinions in the rack.

By the construction of a surrounding the input shaft

Hollow shaft motor, the servo drive is very compact, since in addition to the space for the shaft no additional space for their drive is needed.

Furthermore, can be dispensed with by the arrangement of the pinion with respect to the rack on a pressure piece.

The steering gear according to the invention has preferred compact

Dimensions on and still represents the for heavy vehicles

necessary auxiliary power available.

LIST OF REFERENCE NUMBERS

Hollow shaft motor

motor housing

longitudinal axis

input shaft

torsion bar

pinion shaft

drilling

recess

First paragraph

Second paragraph

Third paragraph

needle roller bearings

First advantage

Second advantage

Rotation angle sensor

magnetic ring

sensor element

stator

rotor

magnet

transmission

gear shaft

cam

driver disc

driving pins straight pins

eccentric

bearing sleeve

bearing seat

First gear

Second gear

Second pinion

First pinion

Rack segment

rack

steering housing

cover

camp

gearing

First paragraph

Second paragraph

nose

camp

cap

opening

Claims

claims

1. steering gear, especially for motor vehicles, with a

Steering housing (41) in which a rack (40) mounted longitudinally displaceable and connected for pivoting steerable wheels with these, wherein the rack (40) with a first toothed segment (38) is provided with a first pinion (37) of a Pinion shaft (6) meshes and wherein the pinion shaft (6) via an input shaft is indirectly connected to a steering wheel, wherein the rack (40) has a second toothed segment (39) which the first toothed segment (38) with respect to the longitudinal axis of the rack (40 ), and that a second pinion (36) is provided, which is connected to the second

Tooth segment (38) is engaged, wherein an electric motor is provided, which indirectly with the second pinion (36) to a reverse rotation mechanically positively coupled first pinion (37) drives

d a d u r c h e c i n e s that the

Electric motor is designed as a hollow shaft motor (1), which is the

Input shaft (4) and / or the pinion shaft (6) at least in one

Part of the shaft partially surrounds.

2. Steering gear according to claim 1, characterized in that the hollow shaft motor (1) drives a transmission shaft (25) via a

Transmission (24) with the pinion shaft (6) is connected.

3. Steering gear according to claim 1 or 2, characterized in that a rotation angle sensor (15) on the input shaft (4) and a

Rotation angle sensor (16) on the pinion shaft (6) are provided.

4. Steering gear according to claim 2 or 3, characterized in that the transmission (24) is a reduction gear.

5. Steering gear according to one of the preceding claims, characterized in that the first and the second pinion (37, 36) are arranged obliquely opposite the rack (40), wherein the plane which the pinion (37, 36) span the longitudinal axis of the Rack (40) cuts at an angle less than 90 °.

6. Steering gear according to one of the preceding claims, characterized

characterized in that the mechanical coupling of the two pinions (37, 36) takes place via gears.

7. Steering gear according to one of the preceding claims, characterized

characterized in that the axes of rotation of the two opposing pinions (37, 36) are arranged at an acute angle to each other.

8. Steering gear according to one of the preceding claims, characterized

characterized in that the toothed segments (38, 39) are arranged in mutually inclined planes.

9. Steering gear according to one of the preceding claims 1 to 5,

characterized in that the axes of rotation of the two opposing pinion (37, 36) are arranged parallel to each other.

10. Steering gear according to one of the preceding claims, characterized

characterized in that the drive-away bearing (47) of the second pinion (36) has a bearing arrangement for adjusting the play of the engagement

Pinion / rack has.