JP2008201155A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve steering feeling of a steering device having a combined operation type operating element. <P>SOLUTION: The steering device 1 is provided with a steering shaft 5 connected to wheels 100; a steering assist motor 70 for energizing rotation of the steering shaft 5; a steering wheel 10 operated by a driver and connected to the steering shaft 5 via bevel gears 6, 7; a support body for rotatably supporting the steering wheel 10 around the steering shaft 5 and around a rotating shaft 4 intersecting with the steering shaft 5; a first rotating angle sensor 62 for detecting a rotating angle of the steering shaft 5; a second rotating angle sensor 11 for detecting a rotating angle of the steering wheel 10 around the rotating shaft 4; and a torque sensor part 61 for detecting torque applied to the steering shaft 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus.

  In a conventional so-called electric power steering device, a torque sensor is provided on a steering shaft that connects a round handle operated by a driver and a steering device for turning steered wheels, and the driver adds the torque sensor to the steering wheel. In general, an operation torque is detected, a steering assist motor is controlled based on the detected operation torque, and a steering assist force generated by the steering assist motor is applied to the steering shaft.

On the other hand, with respect to the conventional round handle that can rotate only in one plane, the operator corresponding to the handle is moved along the spherical surface in order to reduce the operation burden on the driver and improve operability. An operator is also considered (see, for example, Patent Document 1).
In addition, an operator corresponding to the handle is provided so that it can be operated forward and backward and rotated, and the steering shaft can be rotated by a combined operation of the operator's forward and backward operation and rotational operation (hereinafter referred to as a composite operation type operator). Is also considered.
JP 2005-277772 A

  By the way, in the electric power steering device, when a round handle is to be replaced with the composite operation type operator, in the case of the composite operation type operator, a composite operation input to the operator is given a rotational motion of the steering shaft. Therefore, a motion conversion device including a bevel gear or the like is required between the operation element and the steering shaft.

As described above, when the motion conversion device is interposed between the operation element and the steering shaft, torque cross due to the friction element of the motion conversion device is generated, and accordingly, the torque transmitted to the steering shaft is reduced accordingly. Similarly, when the output control of the steering assist motor is performed based on the torque applied to the steering shaft, the driver feels the steering heavy.
Further, since a delay element caused by the motion conversion device occurs, there is a problem that a response delay occurs in the steering assist, and the steering feeling is lowered.

  Accordingly, the present invention provides a steering apparatus that includes a compound operation type operation element and is excellent in steering feeling.

The steering device according to the present invention employs the following means in order to solve the above problems.
According to the first aspect of the present invention, a steering shaft (for example, a steering shaft 5 in an embodiment to be described later) coupled to a steered wheel (for example, a wheel 100 in an embodiment to be described later) and the rotation of the steering shaft are urged. A motor (for example, a steering assist motor 70 in an embodiment described later) and a steering wheel operated by a driver and connected to the steering shaft via gears (for example, a first bevel gear 6 and a second bevel gear 7 in an embodiment described later). An operating element (for example, a handle 10 in an embodiment described later), and a second axis (for example, a rotating shaft in an embodiment described later) that supports the operating element rotatably around the steering shaft and intersects the steering shaft. 4) A support that is rotatably supported around (for example, described later) The housing 3) in the embodiment, the first rotation angle sensor (for example, the first rotation angle sensor 62 in the embodiment described later) for detecting the rotation angle of the steering shaft, and the rotation of the operation element about the second axis A second rotation angle sensor (for example, a second rotation angle sensor 11 in an embodiment described later) for detecting an angle, and a torque sensor (for example, an embodiment described later) that is provided on the steering shaft and detects torque applied to the steering shaft. A torque sensor unit 61), and a steering device (for example, a steering device 1 in an embodiment to be described later).

  According to the second aspect of the present invention, a steering shaft (for example, a steering shaft 5 in an embodiment described later) coupled to a steered wheel (for example, a wheel 100 in an embodiment described later) and the rotation of the steering shaft are urged. A motor (for example, a steering assist motor 70 in an embodiment described later) and a steering wheel operated by a driver and connected to the steering shaft via gears (for example, a first bevel gear 6 and a second bevel gear 7 in an embodiment described later). An operating element (for example, a handle 10 in an embodiment described later), and a second axis (for example, a rotating shaft in an embodiment described later) that supports the operating element rotatably around the steering shaft and intersects the steering shaft. 4) A support that is rotatably supported around (for example, described later) Steering characterized in that it includes a housing 3) in the embodiment and a torque sensor (for example, torque sensor unit 13 in an embodiment described later) provided on the second shaft and detecting torque applied to the second shaft. A device (for example, a steering device 1 in an embodiment described later).

  According to the first aspect of the present invention, the result of comparing the rotation angle of the operating element detected by the second rotation angle sensor about the second axis with the rotation angle of the steering shaft detected by the first rotation angle sensor. The torque of the steering shaft detected by the torque sensor is corrected based on the torque, and the motor is controlled based on the corrected torque, thereby suppressing the torque cross and the delay element generated between the steering shaft and the operation element. Can do. As a result, the response of the steering assist is improved and the steering feeling can be improved.

  According to the second aspect of the present invention, the torque before the torque cross is generated between the steering shaft and the operation element can be detected by the torque sensor, and the torque applied to the second shaft detected by the torque sensor. Does not include a delay element that occurs between the steering shaft and the operation element. By controlling the motor based on the torque detected by the torque sensor, the response of the steering assist is improved and the steering fee is improved. The ring can be improved.

Embodiments of a steering device according to the present invention will be described below with reference to the drawings of FIGS.
[Example 1]
First, a first embodiment of a steering apparatus according to the present invention will be described with reference to the drawings of FIGS.
As shown in FIG. 1, the vehicle steering apparatus 1 is configured by mechanically connecting an operation unit 1 </ b> A that is operated by a driver and a steering unit 1 </ b> B that steers a wheel (steered wheel) 100. Yes. 1 shows the operation unit 1A in a side view and the steered unit 1B in a plan view for convenience of illustration.

  First, the operation unit 1A will be described. FIG. 2 is a partially cutaway perspective view of the operation unit 1A. The operation unit 1A is fixed to the vehicle body and has a rear end disposed in front of the driver's seat, and the steering column 2 is rotatable. A housing (support) 3 attached to the housing 3, a turning shaft (second shaft) 4 rotatably attached to the housing 3, and the rear end of the turning shaft 4 through the steering column 2 and the housing 3. A steering shaft 5 extending in the vicinity, a first bevel gear 6 fixed to the rotating shaft 4 in the housing 3, a second bevel gear 7 fixed to the rear end of the steering shaft 5 and meshing with the first bevel gear 6, A pair of guide rods 9L and 9R having a pinion 8 fixed to the rotating shaft 4, a rack 9a meshing with the pinion 8, and a housing A handle (operating element) 10 of linked round the pivot shaft 4 projecting, a comprises as main consists.

  In the following description, the front-rear direction refers to a direction along the axial direction (X direction in FIG. 2) of the steering shaft 5 and does not necessarily coincide with the front-rear direction of the vehicle body. Further, the rear means the side where the second bevel gear 7 is attached in the steering shaft 5, and the front means the side away from the second bevel gear 7.

Each configuration will be described below.
The housing 3 is partially broken in FIG. 2 and thus appears to be open on the upper side, but is actually closed as shown in the longitudinal sectional view of FIG. The housing 3 includes a rectangular box-shaped gear box 31 that houses the first bevel gear 6, the second bevel gear 7, the pinion 8, and the like, and a cylindrical tube portion 32 through which the steering shaft 5 is inserted. The rear end of the tube portion 32 is inserted into the steering column 2 and is attached to the steering column 2 via a bearing 33 so as to be rotatable and non-detachable.
The steering shaft 5 is rotatably supported by the tube portion 32 of the housing 3 via bearings 51 and 52.

The rotation shaft 4 is arranged so that the axis center thereof is orthogonal to the axis center extension line of the steering shaft 5, passes through the gear box 31 of the housing 3, and is freely rotatable to the gear box 31 via bearings 41 and 42. And it is attached so that it cannot be detached.
A first bevel gear 6 is fixed to the rotating shaft 4, and the first bevel gear 6 meshes with a second bevel gear 7 fixed to the rear end of the steering shaft 5. When the rotation shaft 4 is rotated about its axis, the first bevel gear 6 is also rotated integrally, and the second bevel gear 7 that is meshed with the first bevel gear 6 is further rotated. In FIG. 2, the first bevel gear 6 is shown as being broken, but the first bevel gear 6 and the second bevel gear 7 are both formed in a circular shape.
Further, as shown in FIG. 1, the rotation shaft 4 is provided with a second rotation angle sensor 11 that detects the rotation angle of the rotation shaft 4, and the second rotation angle sensor 11 corresponds to the detected rotation angle. The electrical signal is output to an electronic control device (not shown).

The pinion 8 is fixed to the lower side of the first bevel gear 6 on the rotating shaft 4, and the pinion 8 also rotates together with the rotating shaft 4 when the rotating shaft 4 is rotated around its axis. In FIG. 4, the pinion 8 is not shown.
The guide rods 9L and 9R are arranged in parallel to each other with the pinion 8 interposed therebetween, extend each axis in the front-rear direction, and slidably pass through openings 34 and 34 provided in the rear wall of the gear box 31, The tube body 32 is disposed in parallel to the steering shaft 5 on the outside.

  The guide rods 9L and 9R are provided with racks 9a meshing with the pinions 8 at their respective rear ends, and when the rotating shaft 4 is rotated around the axis center, the guide rods 9L and 9R move in the reverse direction. For example, when the rotation shaft 4 is rotated to the right in FIG. 3 around the axis center, the guide rod 9L moves forward and the guide rod 9R moves backward.

Furthermore, the guide rods 9L and 9R each include a cylindrical guide roller 9b having the same diameter and rotatably supported at each front end thereof. The guide roller 9b is a guide surface formed at the rear end of the steering column 2. Roll 21. In this embodiment, the guide rods 9L and 9R and the guide surface 21 constitute the guide mechanism 12.
The guide surface 21 is composed of two flat surfaces 22 and 23 that are arranged stepwise in the axial direction of the steering shaft 5 and a curved surface 24 that connects the flat surfaces 22 and 23. The planes 22 and 23 are provided in a posture orthogonal to the steering shaft 5, and the upper plane (hereinafter referred to as the upper plane) 22 is positioned forward of the lower plane (hereinafter referred to as the lower plane) 23. is doing.

  As shown in FIG. 5, the curved surface 24 includes a ¼ arc concave curved surface 24 a and a ¼ arc convex curved surface 24 b, and is connected so that the lower end of the concave curved surface 24 a and the upper end of the convex curved surface 24 b share a tangent line. The upper end of the concave curved surface 24 a is connected to the upper plane 22, and the lower end of the convex curved surface 24 b is connected to the lower plane 23. In this embodiment, when the guide roller 9b having the radius r0 rolls between the upper plane 22 and the lower plane 23 via the curved surface 24, the trajectory of the rotation center of the guide roller 9b (see FIG. 5), the radius of the concave curved surface 24a is “R0 + r0” and the convex curved surface 24b has a radius of “R0 + r0” so that the curved line connecting the quarter convex arc and the quarter concave arc having the same radius R0 is a side view. The radius is set to “R0-r0”. For convenience of the following description, the boundary point (inflection point) between the convex arc and the concave arc in the locus of the rotation center of the guide roller 9b is referred to as a neutral point N.

  The operation of the operation unit 1A configured as described above will be described. Here, for convenience of explanation, a stationary coordinate system XYZ fixed to the vehicle body and a dynamic coordinate system X′Y′Z ′ fixed to the housing 3 are set. The origin of the stationary coordinate system XYZ and the origin of the dynamic coordinate system X′Y′Z ′ are the same, and are the intersection of the axis center extension line of the steering shaft 5 and the axis center of the rotating shaft 4. The X-axis and the X′-axis are also common and set to the axial center direction of the steering shaft 5. The Y axis of the stationary coordinate system XYZ is a direction orthogonal to the X axis at the origin and extends to the left and right of the vehicle body, and the Z axis of the stationary coordinate system XYZ is a direction orthogonal to the X axis and the Y axis. The Y ′ axis of the dynamic coordinate system X′Y′Z ′ is perpendicular to the X ′ axis at the origin and extends in the left and right directions of the housing 3, and the Z ′ axis of the dynamic coordinate system X′Y′Z ′ is X ′. The direction is perpendicular to the axis and the Y ′ axis.

  In this steering apparatus 1, when the direction of the wheel 100 is maintained so that the vehicle moves straight, the rotation centers of the guide rollers 9b of the left and right guide rods 9L and 9R are all at the neutral point N described above. It is preset to be positioned. Hereinafter, this state is referred to as a neutral state. As shown in FIG. 2, in the neutral state, the stationary coordinate system XYZ and the dynamic coordinate system X′Y′Z ′ completely coincide. Further, in the neutral state, the axis center of the rotating shaft 4 is located on the Z axis (Z ′ axis), and the handle 10 is located on a plane parallel to the YZ plane (Y′-Z ′ plane). Is set.

In the operation unit 1A, the driver holds the handle 10 and rotates the rotating shaft 4 about the Z ′ axis of the dynamic coordinate system or rotates the housing 3 about the X axis of the stationary coordinate system. The steering shaft 5 can be rotated by any operation. That is, the handle 10 in the steering device 1 is a handle that rotates the rotating shaft 4 about the Z ′ axis of the dynamic coordinate system, and the handle 10 that rotates the housing 3 about the X axis of the stationary coordinate system. This is a combined operation type operation element capable of rotating the steering shaft 5 by a combined operation with 10 rotational operations.
Then, the movement trajectory of any part (for example, the part gripped by the driver) on the handle 10 at that time exists on a spherical surface centered on the origin of the stationary coordinate system XYZ. Further, the first bevel gear 6 rotates around the Z ′ axis of the rotating shaft 4 and revolves around the origin by rotating around the X axis of the housing 3.

However, since the operation unit 1A includes the guide mechanism 12, the handle 10 has regularity in the operation direction. This will be described in detail below.
In the neutral state in which the vehicle is traveling straight, both the left and right guide rollers 9b, 9b are located at the neutral point N. Therefore, at this time, the housing 3 cannot be rotated around the X axis. However, it is possible to rotate the rotation shaft 4 around the Z ′ axis. Therefore, when the wheel 100 is steered from the neutral state, the handle 10 is first rotated around the Z ′ axis. In other words, the handle 10 is moved in the front-rear direction.

For example, in order to turn the vehicle to the right, when the handle 10 is rotated to the right in FIG. 3 around the Z ′ axis, the rotation shaft 4 and the first bevel gear 6 are also rotated to the right in synchronism with the handle 10, and the first bevel gear is rotated. The second bevel gear 7 meshing with 6 rotates clockwise around the X axis when viewed from the rear, and as a result, the steering shaft 5 rotates clockwise around the X axis. At the same time, since the pinion 8 rotates clockwise together with the rotating shaft 4, the left guide rod 9L moves forward and the right guide rod 9R moves rearward due to the meshing of the pinion 8 and each rack 9a. As a result, the left guide The guide roller 9b of the rod 9L rolls on the concave curved surface 24a of the guide surface 21 and climbs upward, and the guide roller 9b of the right guide rod 9R rolls on the convex curved surface 24b of the guide surface 21 and descends downward. Go. As a result, the guide rods 9L and 9R rotate clockwise with respect to the vehicle body from the rear about the X axis, and the housing 3 that engages with the guide rods 9L and 9R also rotates clockwise.
That is, by rotating the handle 10 around the Z ′ axis, the housing 3 is rotated around the X axis, that is, the handle 10 is rotated around the X axis.

  Then, the guide roller 9b of the left guide rod 9L climbs up the concave curved surface 24a to reach the upper plane 22, and simultaneously, the guide roller 9b of the right guide rod 9R also descends the convex curved surface 24b to the lower plane 23. Reach. When the guide roller 9b of the left guide rod 9L hits the upper plane 22, the left guide rod 9L is prevented from further advancement, so that the handle 10 cannot be rotated around the Z 'axis.

Immediately after the guide roller 9b reaches the upper flat surface 22 and the lower flat surface 23, the guide roller 9b of the left guide rod 9L rolls on the upper flat surface 22 so that it can rotate right and cannot rotate left, and the rotation direction is restricted. Is done.
Further, while the guide rollers 9b of the left and right guide rods 9L and 9R are positioned on the upper plane 22 and the lower plane 23, the handle 10 cannot be rotated around the Z ′ axis, and the housing 3 is moved to the X axis. It can only turn around. 2, 3, and 5, the alternate long and two short dashes line indicates the movement locus of the guide roller 9 b.
As described above, when the housing 3 is rotated only around the X axis, the first bevel gear 6 and the second bevel gear 7 are locked without being relatively rotated. Thus, the steering shaft 5 rotates around the X axis.

When the left and right guide rollers 9b and 9b are positioned on the upper plane 22 and the lower plane 23 to return to the neutral state, the guide rollers 9b, guide rods 9L and 9R, the housing 3 and the handle 10 The operations are all the operations opposite to those described above.
Further, when the vehicle is turned left, the handle 10 is rotated counterclockwise in FIG. 3 around the Z ′ axis from the neutral state. In this case, the operation of the left and right guide rods 9L and 9R is the above-described right turn. And vice versa.
In this steering apparatus 1, the handle 10 has a combined movement of forward and backward movement and rotational movement. Therefore, the range in which the left and right arms of the driver do not interfere with each other can be expanded, and the operability is improved.

Next, the steering unit 1B will be described. As shown in FIG. 1, the front end of the steering shaft 5 is connected to a pinion shaft 62 via a torque sensor portion (torque sensor) 61. The torque sensor unit 61 includes, for example, a torsion bar, and is configured to be able to detect torque applied to the steering shaft 5. The torque sensor unit 61 outputs an electrical signal corresponding to the detected torque to the electronic control device.
The steering shaft 5 is provided with a first rotation angle sensor 62 that detects the rotation angle of the steering shaft 5 behind the torque sensor unit 61 and in the vicinity of the second bevel gear 7. Outputs an electric signal corresponding to the detected rotation angle to the electronic control unit.

A pinion 63 of the pinion shaft 62 meshes with a rack 65 of the rack shaft 64, and a wheel 100 is connected to the rack 65 via a tie rod 66 and a knuckle arm 67. When the steering shaft 5 is rotated and the pinion shaft 62 is rotated, the rack shaft 64 moves in the axial direction, and the wheel 100 can be steered.
The pinion shaft 62 is provided with a worm wheel gear 68, and a worm gear 71 provided on the output shaft of the steering assist motor 70 is engaged with the worm wheel gear 68. The steering assist motor 70 applies an auxiliary steering force to the pinion shaft 62 to assist the driver's steering, and biases the rotation of the steering shaft 5.

By the way, as a method for controlling the output of the steering assist motor 70, it is common to detect the torque applied to the steering shaft 5 and control the output of the steering assist motor 70 based on the detected torque.
However, in this steering device 1, the bevel gear mechanism (the first bevel gear 6 and the second bevel gear 7) is provided between the rotating shaft 4 and the steering shaft 5 connected to the handle 10. And a delay element occurs.

  Therefore, in this steering apparatus 1, in order to suppress the torque cross and the delay element in the bevel gear mechanism, the torque detected by the torque sensor unit 61 is corrected according to the rotational angle deviation before and after the bevel gear mechanism, and after the correction The output control of the steering assist motor 70 is performed based on the torque (hereinafter referred to as a correction torque).

An example of a specific correction torque calculation method is shown in Expression (1).
T _M = K _M1 · K _S (θ _C −θ _T ) + K _M2 · K _G (θ _S −θ _C ) (1)
In the equation (1), _{T M} is the correction _torque, K _{M1, K M2} is a control gain, _{K S} is the stiffness of the torque sensor unit 61, _{K G} is the stiffness of the bevel gear mechanism, theta _C is the rotation angle of the steering shaft 5 , Θ _T is the rotation angle of the pinion shaft 62, and θ _S is the rotation angle of the rotating shaft 4.
In this equation (1), “K _S (θ _C −θ _T )” in the first term on the right side is a torque detected by the torque sensor unit 61, and “K _M2 · K _G (θ _S ) in the second term on the right side. −θ _C ) ”is a correction term based on the rotational angle deviation before and after the bevel gear mechanism.

The electronic control unit of the steering device 1 includes an output of the second rotation angle sensor 11 (rotation angle of the rotation shaft 4), an output of the first rotation angle sensor 62 (rotation angle of the steering shaft 5), and torque. based on the output of the sensor section 61 (the torque of the steering shaft 5), wherein the formula (1) calculates a correction torque T _M, performs output control of the steering assist motor 70 based on the correction torque T _M. Thereby, the torque cross and the delay element generated between the steering shaft 5 and the steering wheel 10 can be suppressed. As a result, the response of the steering assist is improved and the steering feeling is improved.

[Example 2]
Next, a second embodiment of the steering apparatus according to the present invention will be described with reference to the drawing of FIG. 6 shows the operation unit 1A in a side view and the steered unit 1B in a plan view for convenience of illustration.
As shown in FIG. 6, in the steering device 1 of the second embodiment, the torque sensor unit 61 is not provided between the steering shaft 5 and the pinion shaft 62, and the second rotation for detecting the rotation angle of the rotating shaft 4 is performed. The first rotation angle sensor 62 that detects the rotation angle of the angle sensor 11 and the steering shaft 5 is not provided.

The rotating shaft 4 is provided with a torque sensor unit (torque sensor) 13 that detects torque applied to the rotating shaft 4, and the electronic control unit of the steering device 1 detects the torque detected by the torque sensor unit 13. Based on the above, the output control of the steering assist motor 70 is performed.
Since other configurations are the same as those of the steering apparatus 1 of the first embodiment, description thereof is omitted.

  According to the steering device 1 of the second embodiment, since the torque sensor unit 13 is disposed on the upstream side of the steering input transmission path with respect to the bevel gear mechanism in which the torque cross and the delay element are generated, the torque sensor unit 13 is based on the output of the torque sensor unit 13. By suppressing the output of the steering assist motor 70, the steering assist control can be performed without being affected by the torque cross and the delay element generated in the bevel gear mechanism. As a result, the response of the steering assist is improved and the steering feeling is improved.

[Other Examples]
The present invention is not limited to the embodiment described above.
For example, in the steering apparatus of the first embodiment, the rotation angle of the steering shaft 5 is detected by the first rotation angle sensor 62. Instead, the movement amount of the rack shaft 64 is detected by the stroke sensor, and the detected stroke is detected. From this, the rotation angle of the steering shaft 5 may be calculated, or the output of an angle sensor that detects the rotation angle of the steering assist motor 70 may be used.

1 is a configuration diagram in Embodiment 1 of a steering device according to the present invention. FIG. FIG. 3 is a perspective view illustrating a partially broken operation portion in the steering apparatus according to the first embodiment. FIG. 3 is a plan view showing a partially broken operation portion according to the first embodiment. FIG. 3 is a longitudinal sectional view of an operation unit according to the first embodiment. FIG. 6 is a side view of a guide surface in the operation unit of the first embodiment. It is a block diagram in Example 2 of the steering device which concerns on this invention.

Explanation of symbols

1 Steering device 3 Housing (support)
4 Rotating shaft (second axis)
5 Steering shaft 6 First bevel gear (gear)
7 Second bevel gear (gear)
10 Handle (operator)
11 Second rotation angle sensor 13 Value sensor (torque sensor)
61 Torque sensor (torque sensor)
62 First rotation angle sensor 70 Steering assist motor (motor)
100 wheels (steered wheels)

Claims (2)

A steering shaft connected to the steered wheels;
A motor for energizing rotation of the steering shaft;
An operator operated by a driver and connected to the steering shaft via a gear;
A support that rotatably supports the operating element around the steering shaft and rotatably supports a second axis that intersects the steering shaft;
A first rotation angle sensor for detecting a rotation angle of the steering shaft;
A second rotation angle sensor for detecting a rotation angle of the operation element around the second axis;
A torque sensor provided on the steering shaft for detecting torque applied to the steering shaft;
A steering apparatus comprising: A steering shaft connected to the steered wheels;
A motor for energizing rotation of the steering shaft;
An operator operated by a driver and connected to the steering shaft via a gear;
A support that rotatably supports the operating element around the steering shaft and rotatably supports a second axis that intersects the steering shaft;
A torque sensor provided on the second shaft for detecting torque applied to the second shaft;
A steering apparatus comprising:

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