JP4428100B2 - Steering device - Google Patents

Description

  The present invention belongs to the technical field of a steering apparatus including a variable gear ratio unit and a power assist actuator.

  A conventional steering apparatus has a variable gear ratio unit that varies a transmission ratio in the middle of a steering transmission system that connects a steering wheel and steered wheels, and a control unit that variably controls the variable gear ratio unit according to a vehicle state. (For example, refer to Patent Document 1).

In addition to this variable gear ratio unit, a steering device is known that includes a power assist actuator that assists the driver's steering force in the middle of the steering transmission system between the variable gear ratio unit and the steered wheels.
Japanese Patent Laid-Open No. 11-49003

  However, in the above prior art, since the variable gear ratio unit and the power assist actuator are arranged apart from each other in the steering transmission system, the degree of freedom in mounting on a vehicle is low, and it is difficult to downsize the device. There was a problem that there was.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a steering device that can be downsized and has a high degree of freedom in mounting on a vehicle.

To achieve the above object, according to the present invention, a variable gear ratio unit having a variable gear ratio actuator provided between a steering input shaft and a steering output shaft, and one of the steering input shaft and the steering output shaft is provided. In a steering device including a power assist actuator that outputs a steering assist force,
The variable gear ratio unit symmetrically arranges the first planetary mechanism connected to the steering input shaft and the second planetary mechanism connected to the steering output shaft by connecting the same rotating elements,
The power assist actuator is connected to a connecting portion between the first planetary mechanism and the second planetary mechanism,
The variable gear ratio actuator is connected to a rotating element other than the rotating element to which the power assist actuator is connected in either the first planetary mechanism or the second planetary mechanism ,
The first planetary mechanism and the second planetary mechanism are coaxially connected to a planetary gear including a sun gear, a carrier supporting the planetary gear, and a ring gear, and a planetary roller including the sun roller, the carrier supporting the planetary roller, and the ring roller. And a torque transmission path by the roller of the geared roller and a torque transmission path by the gear are formed in parallel .

  In the present invention, since the power assist actuator is incorporated in the variable gear ratio unit, the apparatus can be downsized and the degree of freedom of mounting on the vehicle can be increased compared to the case where both units are provided separately. Can do.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 6.

First, the configuration will be described.
FIG. 1 is a configuration diagram of a steering apparatus according to the first embodiment.
As shown in FIG. 1, the steering apparatus according to the first embodiment includes a steering transmission system (column shaft 2, intermediate shaft 14, pinion 15, steering rack 16, and tie rod 17 that connects the steering wheel 1 and a steered wheel (front wheel) 18. ), A variable gear ratio unit 5 for changing the transmission ratio is provided, and a power steering motor 11 having a power steering function for assisting the steering force of the driver is incorporated in the variable gear ratio unit 5.

  The steering input to the steering wheel 1 is transmitted to the column shaft (steering input shaft) 2 → the variable gear ratio unit 5 → the intermediate shaft (steering output shaft) 14 → the pinion 15 → the steering rack 16 → the tie rod 17 → the steered wheel 18. The

  The variable gear ratio unit 5 includes two planetary gear mechanisms having the same shape including a sun gear (solar element) 5a, a carrier (support element) 5d that supports the planetary gear (planetary element) 5b, and a ring gear (annular element) 5c. The first planetary mechanism A and the second planetary mechanism B are provided. The carrier 5 d of the first planetary mechanism A is connected to the column shaft 2, and the carrier 5 d of the second planetary mechanism B is connected to the intermediate shaft 14. Further, the sun gears 5a, 5a of the first planetary mechanism A and the second planetary mechanism B are connected by a member (rotary connecting member) 5e.

  The ring gear 5 c of the first planetary mechanism A is connected to the variable gear ratio control motor 6 via a worm wheel 20 and a worm gear 21. The rotation of the variable gear ratio control motor 6 causes the ring gear 5c of the first planetary mechanism A to rotate, and the rotation amount due to this rotation and the rotation of the carrier 5d is transmitted to the sun gear 5a. The rotation of the sun gear 5a is input to the sun gear 5a of the second planetary mechanism B via the member 5e, and is output to the intermediate shaft 14 from the carrier 5d. The rotation amount of the variable gear ratio control motor 6 is measured by the encoder 7, and the measured value is input to the electronic controller 19.

The member 5e is connected to a power steering motor 11 that outputs a steering assist force to the member 5e, and is provided with an encoder 12 that measures the rotation of the member 5e. The measured value of the encoder 12 is input to the electronic controller 19.
As the motor of the power steering motor 11, a direct motor (hollow motor) with low rotation and high torque is used.

  When the driver steers the steering wheel 1, the steering angle sensor 3 measures the steering angle and inputs the measured value to the electronic controller 19. Similarly, the steering torque sensor 4 measures the steering torque and inputs the measured value to the electronic controller 19.

  Based on the input from each sensor, the electronic controller 19 drives the variable gear ratio control motor 6 so that the target turning angle corresponding to the steering angle is obtained. Further, the power steering motor 11 is driven so as to obtain a target steering assist force based on the input from each sensor.

Next, the operation will be described.
FIG. 2 shows a case where a variable gear ratio unit having a variable gear ratio control motor and a power steering unit having a power steering motor are provided separately in the middle of the steering system. In addition, the same code | symbol is attached | subjected to the component same as Example 1, and description is abbreviate | omitted.

  This steering device is different from the configuration of the first embodiment in that the variable gear ratio unit 5 and the power steering motor 11 are separately provided between the column shaft 2 and the intermediate shaft 14. The power steering motor 11 is connected to the column shaft 2 via a reduction gear including a worm gear 51 and a worm wheel 50. Therefore, the variable gear ratio control motor 6 and the power steering motor 11 are independently controlled by the variable gear ratio control electronic control controller 8 and the power steering controller 13.

  Thus, by using the power steering motor 11, it is possible to arrange the variable gear ratio unit 5 side by side in the steering transmission system, and the apparatus can be downsized as compared with the hydraulic power steering unit. However, since these are arranged in series in the middle of the steering shaft, the dimension in the steering shaft direction becomes large.

  On the other hand, in the steering device of the first embodiment, the dimension in the steering axis direction is reduced by incorporating the power steering motor 11 into the variable gear ratio unit 5. Further, by connecting the power steering motor 11 to the member 5e that connects the sun gears 5a, 5a of the first planetary mechanism A and the second planetary mechanism B, a power steering system using a small motor can be configured. .

  That is, since the first planetary mechanism A has the carrier 5d input and the sun gear 5a output, the rotation speed of the sun gear 5a is increased by the gear ratio of the first planetary mechanism A and the rotation of the ring gear 5c. Yes. By attaching the power steering motor 11 for assisting the steering force to the sun gear 5a that has been accelerated, a space-saving and small steering system with power steering is realized.

Next, the effect will be described.
In the steering device of the first embodiment, the following effects can be obtained.

  (1) In the variable gear ratio unit 5, a member 5e for connecting the sun gears 5a, 5a of the first planetary mechanism A and the second planetary mechanism B is provided, and the column shaft 2 and the carrier 5d of the first planetary mechanism A are provided. Since the intermediate shaft 14 and the carrier 5d of the second planetary mechanism B are connected, and the power steering motor 11 is connected to the member 5e, the variable gear ratio unit and the power steering unit are separately provided. Thus, the apparatus can be reduced in size, and the degree of freedom of mounting on a vehicle can be increased.

  (2) The variable gear ratio control motor 6 is connected to the ring gear 5c of the first planetary mechanism A, and the power steering motor 11 is accelerated by the outputs of the first planetary mechanism A and the variable gear ratio control motor 6. Since the power steering motor 11 is provided with a sufficient speed increase ratio due to the speed increase of the first planetary mechanism A because the first planetary mechanism A has a large speed increase ratio. A motor with a machine is not required, and a steering device equipped with a small space-saving power steering system can be realized.

First, the configuration will be described.
The steering device of the second embodiment is different from the first embodiment in that the variable gear ratio control motor of the variable gear ratio unit is connected to the member 5e via the bevel gear, and the other components are the same. Are denoted by the same reference numerals and description thereof is omitted.

FIG. 3 is a configuration diagram of the steering device of the second embodiment.
As shown in FIG. 3, in the variable gear ratio unit 50, the power steering motor 11 is provided with a bevel gear 10, and the member 5e is provided with a bevel gear 9. That is, in the steering device of the second embodiment, a sufficient speed increasing ratio is given to the power steering motor 11 by the speed increasing ratio of the first planetary mechanism A and the speed increasing ratio of the bevel gears (bevel gears 9 and 10). A reduction gear is not required for the steering motor 11 itself.

Next, the effect will be described.
In the steering device of the second embodiment, in addition to the effect (1) of the first embodiment, the following effects can be obtained.

  (3) Since the power steering motor 11 of the variable gear ratio unit 50 is connected to the member 5e via a reduction gear with a reduction speed ratio such as a bevel gear (bevel gears 9, 10), an inexpensive and compact power steering system is realized. it can.

First, the configuration will be described.
The steering device according to the third embodiment includes a geared roller in which a planetary gear and a planetary roller are integrally formed on the same shaft instead of the planetary gear mechanism as the first planetary mechanism and the second planetary mechanism in the variable gear ratio unit. Unlike the first embodiment, the other components are the same, and the same reference numerals are given to the same parts and the description thereof is omitted.

  FIG. 4 is a cross-sectional view showing the configuration of the variable gear ratio unit 51 of the third embodiment. The first planetary mechanism A and the second planetary mechanism B are geared rollers in which a roller and a gear are integrally formed on the same axis. It is. This geared roller is a planetary mechanism having a sun roller 29 with a sun gear 26, carriers 23 and 30 that support the planetary roller 28 with a planetary gear 27, and a ring roller 25 with a ring gear 24.

  The clearance between the tooth surfaces on the pitch circle of the sun gear 26 and the planetary gear 27 is set larger than the slip amount of the roller in the normal torque range (low torque range) during normal travel.

  The carrier 30 of the first planetary mechanism A is connected to a steering wheel side shaft 32 that is connected to the column shaft 2. The carrier 30 of the second planetary mechanism B is connected to a pinion side shaft 33 that is connected to the intermediate shaft 14. The sun rollers 29 and 29 with the sun gear 26 of the first planetary mechanism A and the second planetary mechanism B are connected to a member 5e to which the power steering motor 11 is connected.

Next, the operation will be described.
In the variable gear ratio unit 51, the torque transmission path at the time of low torque input is the steering wheel side shaft 32 → the carrier 23, 30 of the first planetary mechanism A → the planetary roller 28 → the sun roller 29 → the member 5e → the second planetary mechanism B. The sun roller 29 → the planetary roller 28 → the carrier 23, 30 → the pinion side shaft 33, and the transmission path is formed only by the roller.

  On the other hand, when high torque is input, the steering wheel side shaft 32 → the first planetary mechanism A carriers 23 and 30 → the planetary gear 27 → the sun gear 26 → the member 5e → the second planetary mechanism B sun gear 26 → the planetary gear 27 → carrier. 23, 30 → pinion side shaft 33, and a transmission path is formed only by gears.

  That is, at the time of torque transmission by the roller, if the roller slips beyond the play of the gear, torque transmission is ensured by meshing with the gear. On the other hand, when the torque transmission direction is changed during torque transmission by the gear, a torque transmission path is transiently formed by the roller, and the rotation axis parallelism of multiple gears can be secured by the roller, and the compensation action by the roller Is achieved.

  Therefore, in the normal steering torque range (low torque range), a smooth steering feeling without noise and backlash can be obtained by making use of the torque transmission characteristics of the roller, and in the high torque range exceeding the normal steering torque range, more reliable torque is achieved by the gear. Since transmission is possible, the effect of using a geared roller becomes remarkable.

Next, the effect will be described.
In the steering device of the third embodiment, in addition to the effect (1) of the first embodiment, the following effects can be obtained.

  (4) As the first planetary mechanism A and the second planetary mechanism B of the variable gear ratio unit 51, a roller with a gear in which a roller and a gear are integrally formed on the same axis is provided, and a torque transmission path and a gear by the roller with the gear are provided. Since the torque transmission path is formed in parallel, smooth and reliable torque transmission can be realized by the mutual compensation action by the roller and the gear.

First, the configuration will be described.
The steering device of the fourth embodiment is different from the third embodiment in that the variable gear ratio control motor of the variable gear ratio unit is connected to the member 5e via the bevel gear, and the other components are the same. Are denoted by the same reference numerals and description thereof is omitted.

FIG. 5 is a cross-sectional view illustrating a configuration of the variable gear ratio unit 52 of the fourth embodiment.
As shown in FIG. 5, in the variable gear ratio unit 52, the power steering motor 11 is provided with a bevel gear 10, and the member 5e is provided with a bevel gear 9.

  That is, in the steering device of the fourth embodiment, a sufficient speed increasing ratio is given to the power steering motor 11 by the speed increasing ratio of the first planetary mechanism A and the speed increasing ratio of the bevel gears (bevel gears 9 and 10). A reduction gear is not required for the steering motor 11 itself.

Next, the effect will be described.
In the steering device of the fourth embodiment, in addition to the effect (1) of the first embodiment and the effect (4) of the third embodiment, the following effects can be obtained.

  (5) Since the power steering motor 11 of the variable gear ratio unit 52 is connected to the member 5e via a reduction gear with a reduction speed ratio such as a bevel gear (bevel gears 9 and 10), an inexpensive and small power steering system is realized. it can.

First, the configuration will be described.
In the steering device of the fifth embodiment, in the variable gear ratio unit, the first planetary mechanism A and the second planetary mechanism B are connected by a rod, the variable gear ratio control motor is connected to the first planetary mechanism A, and the power steering. Since the other components are the same as in the third embodiment in that the motor for driving is connected to the second planetary mechanism B, the same reference numerals are given to the same parts and the description thereof is omitted.

FIG. 6 is a cross-sectional view showing the configuration of the variable gear ratio unit 53 of the fifth embodiment.
As shown in the figure, in the variable gear ratio unit 53 of the fifth embodiment, the first member 41 is connected to the sun roller 29 with the sun gear 26 of the first planetary mechanism A, and the sun gear 26 of the second planetary mechanism B. A second member 42 is connected to the attached sun roller 29. The first member 41 and the second member 42 are connected to a torque transmission rod 36 via a first coupling 34 and a second coupling 35.

  The variable gear ratio control motor 6 is connected to the ring roller 25 with the ring gear 24 of the first planetary mechanism A, and the power steering motor 11 is connected to the second member 43 of the second planetary mechanism B. .

Next, the operation will be described.
Input torque from the steering wheel side shaft 32 is transmitted from the carrier 30 of the first planetary mechanism A to the sun roller 29 with the sun gear 26. Subsequently, the light is transmitted from the first member 41 to the second member 42 via the rod 36, and output from the sun roller 29 with the sun gear 26 of the second planetary mechanism B to the carrier 30 and the pinion side shaft 33.

  At this time, since the rotation obtained by increasing the steering input of the driver by the first planetary mechanism A is input to the rod 36, the torque input to the rod 36 can be reduced. Further, since the load applied to the variable gear ratio control motor 6 is small, the motor can be miniaturized.

Next, the effect will be described.
In the steering device of the fifth embodiment, in addition to the effect (1) of the first embodiment and the effect (4) of the third embodiment, the following effects can be obtained.

  (6) A rod in which the sun roller 29 with the sun gear 26 of the first planetary mechanism A and the sun roller 29 with the sun gear 26 of the second planetary mechanism B are arranged with the first coupling 41 and the second coupling 42 at the ends. Since they are connected by 36, the degree of freedom in arrangement of the first planetary mechanism A and the second planetary mechanism B is improved.

  (7) The variable gear ratio control motor 6 is connected to the ring roller 25 with the ring gear 24 of the first planetary mechanism A, and the power steering motor 11 is connected to the sun roller 29 with the sun gear 26 of the second planetary mechanism B. The torque input to the rod 36 can be reduced, and torque fluctuation and torque loss can be suppressed.

First, the configuration will be described.
The steering device of the sixth embodiment is different from the fifth embodiment in that the first planetary mechanism A and the second planetary mechanism B are connected by a cable-type column in the variable gear ratio unit. The same parts are denoted by the same reference numerals and description thereof is omitted.

FIG. 7 is a cross-sectional view showing the configuration of the variable gear ratio unit 54 of the sixth embodiment.
As shown in the drawing, in the variable gear ratio unit 54 of Example 6, the first cable reel 37 is provided on the first member 41 of the first planetary mechanism A, and the second member 42 of the second planetary mechanism B is provided on the second member 42. The second cable reel 38 is provided.

  Two flexible cables 39 and 40 are wound around the first cable reel 37 and the second cable reel 38 in opposite directions. These cables 39 and 40 and the first and second cable reels 37 and 38 constitute a cable column.

  In this cable type column, when the driver rotates the steering wheel 1, one of the two cables 39 and 40 transmits the steering torque input from the driver, and the other cable 40 transmits the steered wheels 18. By transmitting the reaction force torque input from, it exhibits the same function as the column shaft.

Next, the operation will be described.
The input torque from the steering wheel side shaft 32 is transmitted from the carrier 30 of the first planetary mechanism A to the sun roller 29 with the sun gear 26. Subsequently, the signal is transmitted from the first cable reel 37 to the second cable reel 38 via the cable 39 and output from the sun roller 29 with the sun gear 26 of the second planetary mechanism B to the carrier 30 and the pinion side shaft 33. .

  Here, since the cable used for the cable type column generally does not have a high durability limit, it is desirable to make the load torque of the cable as small as possible. Further, when the load torque of the cable is large, the transmission loss of the cable increases, so that the output becomes smaller than the input, and the steering feeling is deteriorated.

  In the sixth embodiment, since the rotation of the steering wheel side shaft 32 is accelerated by the first planetary mechanism A and then transmitted to the cable 39, the load torque of the cable 39 is transmitted from the steering wheel side shaft 32 to the first planetary gear. It becomes smaller than the input torque to the mechanism A, and the load torque of the cable 39 can be reduced.

Next, the effect will be described.
In the steering device of the sixth embodiment, in addition to the effect (1) of the first embodiment and the effect (4) of the third embodiment, the following effects can be obtained.

  (8) Since the sun roller 29 with the sun gear 26 of the first planetary mechanism A and the sun roller 29 with the sun gear 26 of the second planetary mechanism B are connected by a cable column, the first planetary mechanism A and the second planetary mechanism B Can be arranged at any position, and the degree of freedom of mounting on the vehicle is improved.

  (9) The variable gear ratio control motor 6 is connected to the ring roller 25 with the ring gear 24 of the second planetary mechanism B, and the power steering motor 11 is connected to the sun roller 29 with the sun gear 26 of the second planetary mechanism B. The load torque of the cable 39 can be reduced, the transmission loss of the cable can be reduced, and the deterioration of the steering feeling can be suppressed.

(Other examples)
As mentioned above, although the best form for implementing this invention was demonstrated using Examples 1-6, the specific structure of this invention is not limited to Examples 1-6, Even if there is a design change or the like within a range not departing from the gist, it is included in the present invention.

  For example, one of the first planetary mechanism and the second planetary mechanism may be a planetary gear mechanism or a planetary roller mechanism. In this case, a combination in which the first planetary mechanism on the steering wheel side (input side) is a planetary roller mechanism and the second planetary mechanism on the pinion side (output side) is a planetary gear mechanism is most preferable. By adopting such a configuration, it is possible to achieve both the same effects as in the third embodiment, that is, realization of a smooth steering feeling without backlash and reliable torque transmission.

  The first planetary mechanism and the second planetary mechanism are not limited to the configuration of the embodiment as long as the same rotational elements are connected and symmetrically arranged. For example, the input / output may be a ring gear (ring roller) and the sun gears (sun rollers) may be connected, or the input / output may be a carrier and the ring gears (ring rollers) may be connected.

  In Examples 2 and 4, a bevel gear with high transmission efficiency is used as a speed reducer, but other speed reducers may be used. When using a worm and wheel as a speed reducer, consider the failure of the power steering system and set the worm torsion angle to a larger value so that it can be reversed.

  In the fifth embodiment, the position and the number of couplings connected to the rod can be freely set according to the layout. Further, a power steering motor may be attached to the rod.

  In Examples 5 and 6, the power steering motor is a direct motor, but the motor may be connected to the second planetary mechanism via a speed reducer. Moreover, the connection part of the variable gear ratio control motor and the power steering motor in the first planetary mechanism and the second planetary mechanism is not limited to each embodiment.

1 is a configuration diagram of a steering device of Embodiment 1. FIG. FIG. 3 is a configuration diagram of a steering device in which a variable gear ratio unit having a variable gear ratio control motor and a power steering unit having a power steering motor are separately provided in the middle of a steering system. FIG. 6 is a configuration diagram of a steering device according to a second embodiment. It is sectional drawing which shows the structure of the variable gear ratio unit 51 of Example 3. FIG. It is sectional drawing which shows the structure of the variable gear ratio unit 52 of Example 4. FIG. FIG. 10 is a cross-sectional view illustrating a configuration of a variable gear ratio unit 53 according to a fifth embodiment. It is sectional drawing which shows the structure of the variable gear ratio unit 54 of Example 6. FIG.

Explanation of symbols

A 1st planetary mechanism B 2nd planetary mechanism 1 Steering wheel 2 Column shaft 3 Steering angle sensor 4 Steering torque sensor 5 Variable gear ratio unit 5a Sun gear 5b Planetary gear 5c Ring gear 5d Carrier 5e Member 6 Motor for variable gear ratio control 7 Encoder 9 Bevel gear 10 Bevel gear 11 Power steering motor 12 Encoder 14 Intermediate shaft 15 Pinion 16 Steering rack 17 Tie rod 18 Steering wheel 19 Electronic controller 20 Warm wheel 21 Worm gear 22 Planetary roller gear unit 23 Carrier 24 Ring gear 25 Ring roller 26 Sun gear 27 Planetary gear 28 Planetary roller 29 Solar roller 30 Carrier 31 Bearing 32 Steering wheel side shaft 33 Pinion side shaft 34 First cup Ring 35 second coupling 36 rod 37 first cable reel 38 second cable reel 39 Cable 40 Cable 41 first member 42 second member

Claims (5)

Provided between the steering input shaft and the steering output shaft,
A variable gear ratio unit having a variable gear ratio actuator;
A power assist actuator that outputs a steering assist force to one of the steering input shaft and the steering output shaft;
In a steering device with
The variable gear ratio unit symmetrically arranges the first planetary mechanism connected to the steering input shaft and the second planetary mechanism connected to the steering output shaft by connecting the same rotating elements,
The power assist actuator is connected to a connecting portion between the first planetary mechanism and the second planetary mechanism,
The variable gear ratio actuator is connected to a rotating element other than the rotating element to which the power assist actuator is connected in either the first planetary mechanism or the second planetary mechanism ,
The first planetary mechanism and the second planetary mechanism are coaxially connected to a planetary gear including a sun gear, a carrier supporting the planetary gear, and a ring gear, and a planetary roller including the sun roller, the carrier supporting the planetary roller, and the ring roller. A steering device characterized in that a geared roller integrally formed with the gear and a torque transmission path by the roller of the geared roller and a torque transmission path by the gear are formed in parallel . The steering apparatus according to claim 1, wherein
Connecting the steering input shaft and a support element for supporting the planetary element of the first planetary mechanism;
Connecting the steering output shaft and a support element for supporting the planetary element of the second planetary mechanism;
A rotation connecting member for connecting the solar elements of the first planetary mechanism and the second planetary mechanism is provided;
The variable gear ratio actuator is a variable gear ratio control motor connected to an annular element,
A steering apparatus characterized in that the power assist actuator is a power steering motor coupled to a rotary coupling member. The steering apparatus according to claim 2, wherein
A steering apparatus, wherein the power steering motor is connected to a rotary connecting member via a speed reducer. The steering apparatus according to claim 2 or 3,
The rotation connecting member;
A first rotating connecting member connected to the sun element of the first planetary mechanism;
A second rotating connecting member connected to the solar element of the second planetary mechanism;
A rod connected via the first rotating connecting member and the first connecting member, and a rod connected via the second rotating connecting member and the second connecting member;
A steering device characterized by comprising: The steering apparatus according to claim 2 or 3,
The rotation connecting member;
A first rotating connecting member connected to the sun element of the first planetary mechanism;
A second rotating connecting member connected to the solar element of the second planetary mechanism;
A first cable take-up reel provided on the first rotary connection member, a second cable take-up reel provided on the second rotary connection member, and the first cable take-up reel and the second cable take-up reel are connected. A cable-type column having a cable, and
A steering device characterized by comprising:

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