Adjusting device for steering gear mechanism in motor vehicle and steering gear mechanism of motor vehicle

Abstract

The invention relates to an adjustment device 20 for a steering gear mechanism 1, in particular for a motor vehicle, in which, in a gear train having at least three gears, an intermediate gear 27 is arranged such that it can be moved along a straight adjustment line 105 in order to adjust the backlash in the gear train. The intermediate gear 27 is displaceable along a linear adjustment line 105 so that the backlash in the entire gear train is self-adjusted. The invention also relates to a steering gear mechanism 1 of a motor vehicle comprising said adjusting device 20.

Description

Technical Field

[0001] The invention relates to an adjustment device for a steering gear mechanism, in particular for a steering gear mechanism of a motor vehicle, wherein in a gear train having at least three gears, an intermediate gear is arranged such that it can be moved along a straight adjustment line to adjust the backlash in the gear train. Furthermore, the invention also relates to a steering gear mechanism of a motor vehicle comprising the adjustment device. Background Art

[0002] Steering gear mechanisms are commonly used in motor vehicles to steer the wheels. These steering gear mechanisms connect a steering handle (such as a steering wheel) to a rack that acts on the wheels through the ends of track rods, thus moving the wheels. To increase the steering force, the vehicle is equipped with an actuator that amplifies the driver's manual force, making the vehicle easier to control.

[0003] In the area of ​​steering force support, various energy sources are found to be practical, in particular hydraulic, electric and electromechanical systems are now common. The electrification of the drive train of motor vehicles has also led to an increasing use of electromechanical actuators for steering force support.

[0004] The steering assist can be installed at different locations in the steering gear. Common systems already provide assistance to the driver's steering force in the steering column (column drive). Alternatively, the steering assist can also be installed on the rack (rack drive). In rack-and-pinion systems, it is traditional to install the steering assist at a different location from the connection point to the steering column. The required construction space is thus distributed along the rack, which allows the entire arrangement to be better integrated into the vehicle.

[0005] The system for assisting the steering force can also take the form of a steer-by-wire (SbW) system, in which there is no mechanical connection between the steering wheel and the wheels being steered. In this case, the torque required for steering the wheels is provided by an actuator, which adjusts the torque as a function of the steering wheel angle. In particular, the adjustment device according to the invention is designed for use in an actuator for an SbW system.

[0006] In a rack drive system, the torque generated by the motor is transmitted to the spindle nut through one or more gears. The spindle nut in turn transmits the torque to the spindle, where the rotation is converted into translational motion. In this case, it is usually called a rotation / translation gear mechanism.

[0007] However, since the motor speed of the power steering actuator is high, it is necessary to reduce the motor speed because the speed required for the rotation / translation reduction gear mechanism is very low. Single-stage reduction is not found to be feasible, so the reduction gear mechanism is increasingly used multiple times.

[0008] Spur gear tooth arrangements have been identified as step-down gear mechanisms, which require a large amount of construction space. Step-down gear mechanisms are also known, which use a belt to step down the speed from the actuator to the spindle nut. Due to the large distance between the actuator and the spindle nut, it is often necessary to use an intermediate gear in the step-down gear mechanism in order to keep the construction space requirement small.

[0009] Due to production and assembly tolerances, the backlash in spur gear arrangements can vary, which can have a negative impact on operational reliability. Adjusting the backlash in large-scale production is not only costly but also very time-consuming.

[0010] In order to adjust the tooth gap, various systems are currently widely used, but in various systems, only one tooth gap of the gear system can always be adjusted, and the adjustment process is therefore time-consuming and laborious. CN107202157A discloses a device in which the tooth gap between the output gear of the gear mechanism and the intermediate gear is adjusted by a rotation / translation adjuster (such as a cam). Subsequently, the tooth gap between the intermediate gear and the drive gear is adjusted by elongated holes, through which the actuator can be moved relative to the intermediate gear.

[0011] Adjusting the backlash between the intermediate gear and the drive gear involves an additional assembly step, which is associated with additional costs.

[0012] It is therefore an object of the present invention to overcome the disadvantages of the prior art and in particular to provide an adjustment device for a steering gear mechanism in which the adjustment of the backlash of the gear train is simplified. Summary of the invention

[0013] This object can be achieved by an adjustment device according to the invention for a steering gear mechanism in a motor vehicle, wherein a first part of a gear train is present between a drive gear and an intermediate gear, and a second part of the gear train is present between the intermediate gear and an output gear, wherein for adjusting the tooth clearance the intermediate gear is movably arranged along a straight adjustment line, wherein the tooth clearance of at least one part of the gear train can be adjusted.

[0014] Since the intermediate gear can be moved along a linear adjustment line, the backlash adjustment of the entire gear train can be achieved by adjusting only the intermediate gear. This not only saves production costs, but also enables subsequent adjustments, for example after maintenance operations. The steering gear mechanism can also readjust the backlash independently if the geometry of the gear changes during operation due to wear. Due to the adjustment device according to the invention, the backlash can also be adjusted independently in the event of irregular heating or cooling, as may occur, for example, in very hot or cold regions. All these measures help to extend the service life of the steering gear mechanism and maintain correct function over a longer service life.

[0015] The intermediate gear is arranged to be movable in a translational manner along a linear adjustment line, that is to say the axis of rotation of the gear is not fixed relative to the steering gear mechanism housing. The axis of rotation of the intermediate gear is the axis about which the gear rotates together with the meshing gear. Furthermore, provision can also be made for the drive gear not to be displaced via a cam or an elongated hole, but rather for the output gear located on the spindle nut to be displaced.

[0016] The adjustment of the backlash of the gear train can be carried out in the following way. First, the motor flange is displaced together with the drive pinion relative to the housing of the steering gear mechanism by means of a cam or an elongated hole. The backlash between the drive gear and the intermediate gear is thereby adjusted. However, since the intermediate gear is arranged so that it can be displaced along a straight adjustment line, pushing the drive gear towards the intermediate gear causes the intermediate gear to be displaced in the direction of the output gear. Due to this displacement, the backlash between the intermediate gear and the output gear is also adjusted at the same time.

[0017] During assembly, the backlash on at least one of the gear parts can be checked by using a feeler gauge. The backlash on the other parts of the gear train is automatically adjusted accordingly. If the required clearance has been adjusted, the motor flange is fastened to the housing.

[0018] According to a first embodiment, it is provided that the linear adjustment line extends through the rotation axes of the drive gear and the output gear. If the drive gear or the output gear has a cam fastening, the linear adjustment line can pass through at least one of the rotation axes of the cam.

[0019] According to a preferred embodiment, the drive gear, the output gear and the intermediate gear are supported on each other so that: the adjustment of the backlash on one part of the gear train will result in a simultaneous adjustment of the backlash on another part of the gear train. As already described in detail above, the adjustment of the backlash on one part of the gear train will make it possible to achieve the backlash on another part of the gear train by displacing the intermediate gear along a linear adjustment line. If, for example, the gap on one part of the gear train is too small, the intermediate gear will be displaced to another part of the gear train. Due to the displacement of the intermediate gear, the backlash is automatically adjusted. The meshing gears generate a force on the intermediate gear, which acts along a linear adjustment line. This force moves the intermediate gear to another part of the gear train, thereby generating a force balance inside the gear train, and the intermediate gears are therefore arranged on the linear adjustment line.

[0020] According to one embodiment, it is provided that one of the drive gear and the output gear is supported so as to be movable in rotation and translation. For example, the drive or output gear can be adjusted by a cam. However, the drive or output gear can also be displaced along another straight line, for example, by an elongated recess, such as an elongated hole.

[0021] Another advantageous embodiment provides that the respective other of the output gear and the drive gear is supported in a fixed manner. It is provided that only the drive gear or only the output gear is arranged displaceably, while the other of the output gear or the drive gear is fixedly supported. This is sufficient, since the displacement of the intermediate gear and the other gear is sufficient to adjust the backlash between the two parts of the gear train. Due to the construction of the steering gear mechanism, it is particularly advantageous that the drive gear is displaceably arranged and the output gear has a fixed bearing. A fixed bearing means that the axis of the gear cannot be moved relative to the steering gear mechanism housing. In contrast, the other gear can be arranged as a so-called floating bearing, which enables the gear to be moved in at least one direction.

[0022] According to another aspect of the invention, the steering gear mechanism has a power assist device having at least one drive unit and a drive controller. The power assist device can in particular be in the form of an electric motor, wherein the electric motor can have a single winding or a double winding. In addition, it can be provided that the power assist device drives the drive gear hydraulically or pneumatically. In any case, the power assist device must be constructed so that it can rotatably drive the drive gear.

[0023] The drive control device is constructed so that the control of the power-assist device drive unit can be realized. For this purpose, the drive control device can include, in particular, hydraulic or pneumatic valves, electric actuator elements or power electronics units, which can realize the control of the drive unit. The drive control device can obtain the signals required for the control from sensors, such as steering angle sensors on the handle. In particular, it can be provided that the sensor predetermines the required steering angle on the handle, and the drive control device controls the drive device towards this steering angle in order to obtain the steering angle on the steering wheel of the motor vehicle.

[0024] According to another embodiment, it is provided that the drive unit is supported so as to be displaceable in rotation and translation. In conventional drive units, such as electric motors, if the drive unit is displaced, the drive gear is displaced together with the drive unit. Thus, displacing the drive unit relative to the steering gear mechanism housing is sufficient to displace the drive gear as well. However, it is also possible to configure only the drive gear so as to be displaceable in rotation and translation without moving the drive unit.

[0025] Another aspect of the invention provides that the intermediate gear is supported in a recess extending along the linear adjustment line. The recess can in particular be in the form of an elongated hole. However, any other form of recess that enables the intermediate gear to be displaced along the linear adjustment line can also be used.

[0026] According to another embodiment, an adjustment direction is provided from the gap between the teeth of a steering gear mechanism to support the steering force in a motor vehicle, the steering gear mechanism comprising: a bracket; a drive gear connected to a drive; an output gear that drives a rotation / translation gear mechanism, and the drive gear is arranged in a fixed manner relative to the housing of the steering gear mechanism relative to the rotation axis of the bracket; and an intermediate gear connecting the drive gear to the output gear, wherein the intermediate gear is arranged so that it can be displaced in a translational manner along a linear adjustment line.

[0027] The bracket of the steering gear mechanism is designed so that it receives a part of the support of the drive gear, the intermediate gear or the output gear. For this purpose, the bracket can have a recess in which there is a pressed-in roller bearing, in which the axis of rotation of the gear extends. In addition, the bracket may also have a cavity in which the intermediate gear can be adjusted along a straight line. The bracket also represents a connection between the drive unit, such as an electric motor, and the steering gear mechanism. In particular, a translational and rotational adjustment unit, such as a cam, can be provided for this purpose. However, it is also possible to insert a further element between the drive unit and the bracket, which further element performs a rotational and translational movement of the drive unit. Furthermore, it is provided that the bracket, together with other components, forms the housing of the steering gear mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, advantages and characteristics of the present invention will be explained with reference to the description of preferred embodiments of the present invention and the accompanying drawings, in which:

[0029] Figure 1 : shows a schematic diagram of the adjustment device;

[0030] Figure 2 : shows a sectional view of a steering gear mechanism with an adjustment device according to the invention, wherein the section passes through the drive gear, the intermediate gear and the output gear; and

[0031] Figure 3 : shows an example of a steering gear mechanism according to the invention, which has two drive units and an adjustment device according to the invention. DETAILED DESCRIPTION

[0032] Figure 1 1 shows a schematic diagram of an adjustment device 20. In this example, the drive gear 23 meshes with an intermediate gear 27, which in turn meshes with an output gear 30. The rotation axis 101 of the drive gear, the rotation axis 103 of the intermediate gear and the rotation axis 104 of the output gear are all arranged along a straight adjustment line 105. The rotation axis 103 of the intermediate gear is supported in two opposite recesses 26 extending along the straight adjustment line 105.

[0033] The drive gear or the output gear comprises a cam 106 in order to enable displacement of the rotation axis of the gear to be adjusted. In the schematic diagram shown, the drive gear 23 can be adjusted by means of the cam 106. Due to the rotation and translation movement of the cam 106, the rotation axis 101 of the drive gear is displaced on a circular path 102. In this case, the linear adjustment line 105 can extend through any position of the rotation axis of the cam 102.

[0034] Figure 2 A sectional view of an adjustment device 20 according to the invention is shown, with a section through a drive gear, an intermediate gear and an output gear. In order to generate power assistance, the steering gear mechanism 1 has a drive unit 2, which transmits a rotational force to a rotor shaft 21. The rotor shaft 21 is in turn connected to a drive gear 23 in a rotationally fixed manner.

[0035] The motor torque transmitted to the driving gear 23 is transmitted to the intermediate gear 27 through the first part of the gear train 25. The intermediate gear 27 can move along the recess 26. Figure 2As shown, a recess 26 is provided along an imaginary line, in this case a section between the drive gear, the intermediate gear and the output gear. The intermediate gear 27 is in turn connected to the output gear 30 via a second part of the gear train 28. The adjustment device 20 surrounds the housing of the steering gear mechanism, which includes the bracket 24. Preferably, the drive unit 2 is fixed to a housing part arranged opposite the bracket 24.

[0036] The output gear transfers the torque of the intermediate gear 27 to the spindle nut 31 of the rotation / translation gear mechanism 32. The torque applied by the drive unit 2 is transmitted to the spindle nut 31 through the gear train, and the spindle 29 in the spindle nut 31 generates the translation movement of the track rod end 5. The rotation / translation gear mechanism 32 can especially be in the form of a ball screw drive, wherein Figure 2 The roller components of the gear mechanism are not shown.

[0037] from Figure 2 As can be seen in the figure, the intermediate gear 27 can be freely displaced along the recess 26. If, for example, the backlash between the drive gear 23 and the intermediate gear 27 becomes too small, i.e., too small a backlash is generated, the intermediate gear 27 will move along the recess 26 in the direction of the output gear 30, as described above. If the gap between the intermediate gear 27 and the output gear 30 becomes too small, the movement direction of the intermediate gear 27 will be reversed accordingly.

[0038] In addition, the recess 26 can also be formed specifically in the bracket 24, wherein the recess 26 can also be arranged only in a part of the bracket. Figure 2 As shown, the bracket 24 partially receives the bearing of the rotation axis of the gear train. Between the drive unit 2 and the motor flange 22, a connection to the bracket 24 is also formed. As shown, the connection between the motor flange 22 and the bracket 24 can be realized by a screw connection. In particular, the motor flange 22 can also be connected to the bracket 24 by a cam 106.

[0039] Figure 3 A steering gear mechanism 1 is shown, which has two drive units 2 with associated drive controllers 3. However, in a variant not shown, only one drive unit 2 controlled by a drive controller may be provided. Both drive units 2 act via a gear train (neither shown) on a main shaft in the steering gear mechanism 1, thereby generating a force on a track rod end 5. The track rod end 5 is fixed to the wheel suspension of the steered wheel and generates a steering force thereto.

[0040] The steering command is implemented by connecting the steering handle from the drive unit to the steering gear unit 1 via the steering column connection 4 on the steering gear unit, or by means of a steer-by-wire system in which the drive control unit 3 is integrated. In the first case, the steering column transmits the force applied by the driver to the steering gear unit 1, which is detected by the control unit and the drive control unit 3 is controlled accordingly. It is also possible to equip the steering gear unit 1 with one or more drive units 2. In particular in the case of heavy motor vehicles or multi-purpose vehicles, multiple drive units and, if applicable, multiple drive controllers 3 are required to apply the steering force.

[0041] If necessary, some independent features can be selected from the above-mentioned combination of features and used in combination with other features according to the possible structural and / or functional relationship between these features to define the subject matter of the claim. The order and / or number of steps of the method can be changed. These methods can be combined with each other, for example, to form an overall method. Reference numerals list

[0042] 1 Steering gear mechanism

[0043] 2 drive units

[0044] 3. Drive controller

[0045] 4 Steering column connector

[0046] 5 Track rod ends

[0047] 20 Adjustment device

[0048] 21 Rotor shaft

[0049] 22 Motor flange

[0050] 23 driving gear

[0051] 24 brackets

[0052] 25 The first part of the gear train

[0053] 26 recesses

[0054] 27 Intermediate gear

[0055] 28 The second part of the gear train

[0056] 29 Spindle

[0057] 30 Output gear

[0058] 31 Spindle nut

[0059] 32 Rotation / Translation Gear Mechanism

[0060] 101 Rotation axis of driving gear

[0061] 102 Rotation axis of cam

[0062] 103 Rotation axis of intermediate gear

[0063] 104 Rotation axis of output gear

[0064] 105 straight line adjustment line

[0065] 106 Cam

Claims

1. An adjustment device (20) for a steering gear mechanism (1) in a motor vehicle, wherein: A first part (25) of the gear train is present between the drive gear (23) and the intermediate gear (27), and a second part (28) of the gear train is present between the intermediate gear (27) and the output gear (30), wherein for adjusting the backlash, the intermediate gear (27) is movably arranged along a linear adjustment line (105), wherein the backlash of at least one part (25, 28) of the gear train can be adjusted.

2. The adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to claim 1, wherein: The straight adjustment line (105) extends through the rotation axis of the output gear (104) and the rotation axis of the drive gear (101).

3. An adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to claim 1 or 2, wherein: The drive gear (23), output gear (30) and intermediate gear (27) are mutually supported so that adjustment of the backlash on one of the parts (25, 28) of the gear train results in a synchronous adjustment of the backlash on one of the other parts (28, 25) of the gear train.

4. An adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to any one of the preceding claims, wherein: One of the driving gear (23) and the output gear (30) is supported so as to be displaceable in rotation and translation.

5. The adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to claim 4, wherein: The respective other of the output gear (30) and the drive gear (23) is supported in a fixed manner relative to a housing of the steering gear mechanism.

6. An adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to any one of the preceding claims, wherein: The intermediate gear (27) is supported to be able to slide along the straight adjustment line (105).

7. An adjustment device (20) for a steering gear mechanism (1) in a motor vehicle according to any one of the preceding claims, wherein: The intermediate gear (27) is supported in a recess (26) which extends along the linear adjustment line (105).

8. A steering gear mechanism (1) for a motor vehicle having an adjustment device (20), in particular an adjustment device (20) as claimed in any one of the preceding claims, wherein: The steering gear mechanism (1) has a power assist device, which has a drive control device (3) and at least one drive unit (2).

9. The steering gear mechanism (1) for a motor vehicle with an adjustment device (20) according to claim 8, wherein: The drive unit (2) is supported so as to be displaceable in rotation and translation relative to the housing of the steering gear.

10. A steering gear mechanism (1) for a motor vehicle according to claim 8 or 9, comprising an adjustment device (20) according to claims 1 to 7.

11. An adjusting device (20) for adjusting the backlash between gears of a steering gear mechanism (1) for a steering force assist device in a motor vehicle, the adjusting device comprising Bracket (24), a drive gear (23), the drive gear being connected to the drive unit (2), an output gear (30) which drives a rotation / translation gear mechanism (32), and the axis of rotation (104) of the drive gear is arranged in a fixed manner relative to the bracket (24), and an intermediate gear (27) connecting the drive gear (23) to the output gear (30), wherein The intermediate gear (27) is arranged to be displaceable along a linear adjustment line (105).

12. The adjustment device according to claim 11, wherein: A first part (25) of the gear train is present between the drive gear (23) and the intermediate gear (27), and a second part (28) of the gear train is present between the intermediate gear (27) and the output gear (30), wherein the adjustment device is particularly designed as an adjustment device according to any one of claims 2 to 9.

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