JP4936052B2 - Vehicle steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the manufacturing cost and engaging noise of a planetary gear mechanism in a steering device for a vehicle capable of varying the transmission ratio of a turning angle of a turning wheel with respect to a steering angle of a steering member. <P>SOLUTION: The planetary gear mechanism 17 comprises a first sun gear 19 connected to the steering member, a second sun gear 20 connected to the turning wheel, two planetary gears 21 for meshing with both of the first and second sun gears 19, 20, and a carrier 22 for rotatably and integrally rotatably supporting the planetary gear 21 around an axis line L. A tooth part forming part 21a of each planetary gear 21 is integrally formed by using a single member. At least one of the first and second sun gears is formed to be a profile shifted gear, the addendum modification coefficients x1, x2 are different, and the difference between the numbers of teeth z1, z2 is set to be 2. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vehicle steering apparatus capable of changing a transmission ratio of a turning angle of a steered wheel to a steering angle of a steering member.

Some of the vehicle steering devices described above change the transmission ratio using a planetary gear mechanism (see, for example, Patent Documents 1 and 2).
JP 2002-240729 A JP 2004-224085 A

Such a vehicle steering apparatus is required to be downsized . The present invention aims to solve this problem.

In order to achieve the above object, the present invention provides a steering shaft (3) including a first part (5) connected to the steering member (2) and a second part (6) connected to the steered wheels (4L, 4R). A variable transmission ratio mechanism (17) capable of changing the transmission ratio (θ2 / θ1) as the ratio of the steering angle (θ2) of the steered wheels (4L, 4R) to the steering angle (θ1) of the steering member (2); A reaction force compensation motor (23) for compensating for the steering reaction force of the steering member (2) due to the operation of the transmission ratio variable mechanism (17), and the transmission ratio variable mechanism (17) said first and second portions (5,6) differentially rotatably coupling comprises a planetary gear mechanism (17) driven by a motor planetary gear mechanism (18), motor the planetary gear mechanism ( 18) and the reaction force compensating motor (23) are both arranged coaxially with the steering shaft (3). Is, the planetary gear mechanism (17) includes a first sun gear (19) communicating with said first portion (5), a first axis which coincides with the axis (L) of the sun gear (19) and (L) And two planetary gears (21) meshing with both the first and second sun gears (19, 20; 19, 20A) and the second sun gear (20; 20A) connected to the second part (6). And a carrier (22) supporting these planetary gears (21) so as to be rotatable and integrally rotatable about the axis (L) of the first and second sun gears (19, 20; 19, 20A). The carrier (22) is rotationally driven by the planetary gear mechanism motor (28), and the toothed portion forming portion (21a) of each planetary gear (21) is integrally formed using a single member. First and second sun gears (19, 20; 19, 2 A) is at least one dislocation gears shift coefficient (x1, x2; unlike x1, x2A) (including zero) of phase, and another number of teeth (z1, z2) for a vehicle the difference is 2 A steering device (1) is provided.
In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.
According to the present invention, the planetary gear mechanism motor and the reaction force compensating motor are arranged coaxially with the steering shaft. As a result, the amount of the planetary gear mechanism motor and the reaction force compensation motor protruding in the radial direction of the steering shaft can be reduced, and the vehicle steering apparatus can be reduced in size .

Further , by forming the toothed portion forming portion of the planetary gear integrally with a single member, a gear member meshing with the first sun gear and a gear member meshing with the second sun gear are formed to form the planetary gear. Need not be formed separately, and as a result, the number of parts can be reduced and the manufacturing cost can be significantly reduced. Further, by making the shift coefficients of the first and second sun gears having different numbers of teeth different, the distance between the planetary gear and the first sun gear and the axis of the planetary gear and the second sun gear are changed. The distance can be made to coincide with each other, and smooth engagement can be realized. Furthermore, by setting the difference in the number of teeth between the first and second sun gears to 2, two planetary gears can be used, and by making the distribution of the transmission force uniform, the meshing noise can be reduced, and the first In addition, the strength of the second sun gear can be sufficiently secured. That is, when only one planetary gear is used, the load applied to the planetary gear is large and the meshing sound is increased. If three or more planetary gears are used, the difference in the number of teeth between the first and second sun gears must be three or more, and the shift coefficient of at least one of the first and second sun gears must be increased. As a result, if a gear with positive displacement (for example, a dislocation coefficient of 1.5) is used, sufficient bristle cannot be secured, and if a gear with negative displacement (for example, a dislocation coefficient of -1.5) is used, It is difficult to secure a sufficient thickness at the root of the tooth.
In the present invention, the first part (5) includes an input member (5a) to which a steering torque (T) is input from the steering member (2), the input member (5a), and a torsion bar (7). And an output member (5b) that is coupled so as to be relatively rotatable and outputs the steering torque (T) to the planetary gear mechanism (17).
In the present invention, a housing (31) for accommodating the planetary gear mechanism (17) is provided, and the reaction force compensating motor (23) is the output of the first portion (5) of the steering shaft (3). It is preferable to have a rotor (23a) that can rotate integrally with the member (5b), and a stator (23b) that surrounds the rotor (23a) and is accommodated in the housing (31).

In the present invention, the number of teeth (z1, z2, z3) of the first sun gear (19), the second sun gear (20; 20A) and the planetary gear (21) is in the range of 10 to 30, respectively. (Claim 4 ). By setting the number of teeth of each gear to 10 or more, the impact of each meshing between the planetary gear and the corresponding first and second sun gears can be reduced, and noise can be reduced. Moreover, by setting the number of teeth to 30 or less, the speed ratio between the carrier driven when changing the transmission ratio and the second sun gear can be prevented from becoming too large. As a result, the meshing sound of the gear can be reduced. Can be suppressed.

In the present invention, the absolute values of the dislocation coefficients (x1, x2; x1, x2A) of the first and second sun gears (19, 20; 19, 20A) are each preferably 1.3 or less (claims) Item 5 ). In this case, it is possible to prevent the tooth depth from becoming too low in the forwardly shifted gear and to secure a sufficient thickness of the tooth tip. Further, it is possible to prevent the tooth root thickness from becoming too small in the negatively shifted gear.

In the present invention, the shift coefficient (x2; x2A) of the sun gear (20; 20A) having a large number of teeth among the first and second sun gears (19, 20; 19, 20A) is a sun gear having a small number of teeth (x2; x2A). which is preferably smaller than the addendum modification coefficient of 19) (x1) (claim 6). In this case, the backlash between the sun gear and the planetary gear can be reduced.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle steering apparatus 1 according to an embodiment of the present invention. Referring to FIG. 1, a vehicle steering apparatus 1 applies a steering torque applied to a steering member 2 such as a steering wheel to left and right steered wheels 4L and 4R via a steering shaft 3 as a steering shaft. The function of changing the transmission ratio θ2 / θ1 of the turning angle θ2 of the steered wheels 4L and 4R with respect to the steering angle θ1 (rotation angle) of the steering member 2 is provided. .

The vehicle steering apparatus 1 includes a steering member 2 and a steering shaft 3 as a steering shaft connected to the steering member 2. The steering shaft 3 includes a first shaft 5 as a first portion, and a second shaft 6 as a second portion disposed on the same axis L as the first shaft 5. .
The first shaft 5 has an input shaft 5 a connected to the steering member 2, and an output shaft 5 b connected to the input shaft 5 a and the torsion bar 7 so as to be relatively rotatable. The permissible value of relative rotation between the input shaft 5a and the output shaft 5b via the torsion bar 7 is a slight value, and it can be considered that the input shaft 5a and the output shaft 5b rotate substantially integrally.

A planetary gear mechanism 17 as a transmission ratio variable mechanism is provided between the output shaft 5 b of the first shaft 5 and the second shaft 6. The second shaft 6 is connected to the steered wheels 4L and 4R through a universal joint 9, an intermediate shaft 10, a universal joint 11, and a steering mechanism 12.
The steering mechanism 12 includes a pinion shaft 13 that is connected to the universal joint 11, a rack 14 a that has a rack 14 a that meshes with the pinion 13 a at the tip of the pinion shaft 13, and that extends in the left-right direction of the vehicle. Knuckle arms 16R and 16L connected to the pair of end portions via tie rods 15R and 15L, respectively.

  With the above configuration, the steering torque from the steering member 2 is transmitted to the steering mechanism 12 via the first shaft 5, the planetary gear mechanism 17, the second shaft 6, and the like. In the steering mechanism 12, the rotation of the pinion 13a is converted into the movement of the rack shaft 14 in the axial direction, and the corresponding knuckle arms 16R and 16L rotate through the tie rods 15R and 15L, respectively. Thereby, the corresponding steered wheels 4R and 4L connected to the knuckle arms 16R and 16L are respectively steered.

The planetary gear mechanism 17 connects the output shaft 5b of the first shaft 5 and the second shaft 6 so as to be differentially rotatable, and the gear ratio between the output shaft 5b and the second shaft 6 is changed. It is possible. By changing the speed ratio, the transmission ratio θ2 / θ1 is changed.
The planetary gear mechanism 17 includes a first sun gear 19 as a first gear (sun gear) that can rotate integrally along the same axis L as the output shaft 5 b of the first shaft 5, and a first sun gear 19. And the second sun gear 20 as a second gear (sun gear) that can rotate integrally with the second shaft 6, and both the first and second sun gears 19, 20. A planetary gear 21 as a meshing planetary gear, and a carrier 22 that supports the planetary gear 21 so as to rotate and to rotate integrally around the axis L of the first and second sun gears 19 and 20 (in a revolving manner). is doing.

The first sun gear 19 is connected to the steering member 2 via the first shaft 5, and the second sun gear 20 is connected to the steered wheels 4L and 4R via the second shaft 6 and the like.
Each of the first and second sun gears 19 and 20 and the planetary gear 21 is provided as a rotation transmission element, and is formed, for example, using a spur gear as an external gear having teeth formed on the outer periphery. In addition, as each gear 19,20,21, you may use the other gears which have mutually parallel axes | shafts, such as a helical gear.

The planetary gears 21 are for associating the first and second sun gears 19 and 20 with each other, and two planetary gears 21 are arranged at equal intervals in the circumferential direction of the steering shaft 3. Each planetary gear 21 has an axis M parallel to the axis L and meshes with both the first and second sun gears 19 and 20, and can rotate around the axis M and revolve around the axis L. is there.
The planetary gear mechanism motor 18 is for rotating the carrier 22. By changing the rotation speed of the carrier 22 about the axis L, the transmission ratio between the first sun gear 19 and the second sun gear 20 is changed, and the transmission ratio θ2 / θ1 is changed.

The planetary gear mechanism motor 18 is composed of, for example, a brushless motor disposed coaxially with the steering shaft 3. The rotor 18 a is fixed to the carrier 22 so as to be integrally rotatable. The rotor 18 a surrounds the rotor 18 a and is fixed to the housing 31. Stator 18b.
The vehicle steering apparatus 1 is provided with a reaction force compensation motor 23 for compensating for a steering reaction force acting on the steering member 2 in association with the operation of the planetary gear mechanism 17. The reaction force compensating motor 23 is composed of, for example, a brushless motor arranged coaxially with the steering shaft 3, and includes a rotor 23a fixed to the output shaft 5b of the first shaft 5 so as to be integrally rotatable, and the rotor 23a. And a stator 23 b fixed to the surrounding housing 31.

The planetary gear mechanism motor 18 and the reaction force compensation motor 23 are controlled by a control unit 24 including a CPU, a RAM, and a ROM, respectively. The control unit 24 is connected to the planetary gear mechanism motor 18 via the drive circuit 25a, and is connected to the reaction force compensation motor 23 via the drive circuit 25b.
Further, a steering angle sensor 26, a torque sensor 27, a turning angle sensor 28, a vehicle speed sensor 29, and a yaw rate sensor 30 are connected to the control unit 24, respectively.

  From the steering angle sensor 26, a signal about the rotation angle of the input shaft 5a of the first shaft 5 is input as a value corresponding to the steering angle θ1 that is the operation amount from the steering neutral position of the steering member 2. From the torque sensor 27, a signal regarding the transmission torque in the first shaft 5 is input as a value corresponding to the steering torque T acting on the steering member 2. From the turning angle sensor 28, a signal regarding the rotation angle of the second shaft 6 is input as a value corresponding to the turning angle θ2. A signal regarding the vehicle speed V is input from the vehicle speed sensor 29. A signal regarding the yaw rate γ of the vehicle is input from the yaw rate sensor 30.

The controller 24 controls the driving of the planetary gear mechanism motor 18 and the reaction force compensation motor 23 based on the input signals from the sensors 26 to 30.
FIG. 2 is a cross-sectional view of a main part of FIG. With reference to FIG. 2, the planetary gear mechanism 17 and the like are accommodated in a housing 31. The housing 31 is a cylindrical member made of, for example, an aluminum alloy, and is supported by the vehicle body 32.

The input shaft 5a of the first shaft 5 is rotatably supported by the housing 31 via a first bearing 33 made of a roller bearing or the like. The output shaft 5b is rotatably supported by the housing 31 via a second bearing 34 formed of a rolling bearing such as a single row angular ball bearing.
The rotor 23a of the reaction force compensating motor 23 is fixed to the outer peripheral surface of the intermediate portion of the output shaft 5b. The stator 23 b of the reaction force compensating motor 23 is fixedly fitted in the housing 31.

An intermediate portion of the second shaft 6 is rotatably supported by the housing 31 via a third bearing 35 made of a rolling bearing such as a single row angular ball bearing.
The first sun gear 19 of the planetary gear mechanism 17 is formed integrally with the output shaft 5b of the first shaft 5 using a single member, and is located at one end of the output shaft 5b. The second sun gear 20 is formed integrally with the second shaft 6 using a single member, and is positioned at one end of the second shaft 6.

Each planetary gear 21 has a tooth portion forming portion 21a meshing with both the first and second sun gears 19 and 20, and support shafts 21b and 21c extending from each of a pair of end portions of the tooth portion forming portion 21a. ing.
The carrier 22 includes one end 36 that supports one support shaft 21 b of each planetary gear 21, the other end 37 that supports the other support shaft 21 c of each planetary gear 21, and between the one end 36 and the other end 37. And an intermediate portion 38 for connecting the two.

  3 is a cross-sectional view taken along line III-III in FIG. Referring to FIGS. 2 and 3, one end portion 36 of carrier 22 rotatably supports output shaft 5 b via a fourth bearing 39 made of a rolling bearing such as a roller bearing. An annular flange 40 extending along the axial direction of the steering shaft 3 is formed at the one end 36. The collar portion 40 is rotatably supported by the housing 31 via a fifth bearing 41 made of a rolling bearing such as a single row angular ball bearing.

In addition, one end portion 36 of the carrier 22 rotatably supports one support shaft 21b of each planetary gear 21 via a corresponding sixth bearing 42. Each sixth bearing 42 is composed of, for example, a roller bearing.
4 is a cross-sectional view taken along line IV-IV in FIG. 2 and 4, the other end portion 37 of the carrier 22 rotatably supports the second shaft 6 via a seventh bearing 43 formed of a rolling bearing such as a roller bearing. The other end portion 37 is formed with an annular flange portion 44 extending along the axial direction of the steering shaft 3. The flange portion 44 is rotatably supported by the housing 31 via an eighth bearing 45 made of a single row angular ball bearing or the like.

  The other end 37 of the carrier 22 rotatably supports the other support shaft 21c of each planetary gear 22 via a corresponding ninth bearing 46. Each ninth bearing 46 is formed of, for example, a roller bearing. The intermediate portion 38 of the carrier 22 is arranged in the circumferential direction of the toothed portion forming portion 21a of each planetary gear 21 and the steering shaft 3, and connects the one end portion 36 and the other end portion 37 so as to be integrally rotatable.

A rotor 18 a of the planetary gear mechanism motor 18 is fixed to the outer peripheral surface of the other end 37 of the carrier 22. The stator 18b of the planetary gear mechanism motor 18 is fitted into the housing 31 and fixed.
The feature of the present embodiment is that two planetary gears 21 are provided, and the tooth portion forming portions 21a of the planetary gears 21 and 21 are integrally formed using a single member. At least one of the second sun gears 19 and 20 (in this embodiment, the first sun gear 19) is changed to a shift gear, the shift coefficients x1 and x2 are different, and the first and second sun gears 19 are different. , 20 has a difference in the number of teeth of 2.

The planetary gears 21 are arranged at equal intervals around the axis L of the first and second sun gears 19 and 20 at intervals of 180 °.
FIG. 5 is a cross-sectional view taken along line VV in FIG. 2 and shows the meshing between the planetary gear 21 and the first sun gear 19. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 2 and shows the meshing between the planetary gear 21 and the second sun gear 20.

Referring to FIGS. 5 and 6, the tooth portion forming portion 21 a of each planetary gear 21 has the same shape over the entire region in the tooth trace direction, and is formed by a single tooth creation process. Is. The tooth portion forming portion 21a includes a plurality of tooth portions 50 and a connection portion 51 that connects the tooth portions 50 to each other.
In the present embodiment, of the first and second sun gears 19 and 20, only the first sun gear 19 is a shift gear. For example, the first sun gear 19 has the number of teeth z1 = 22 and the shift coefficient x1 = 1.251, and the second sun gear 20 has the number of teeth z2 = 24 and the shift coefficient x2 = 0.

That is, the first sun gear 19 is a normal shift gear, and the second sun gear 20 is a standard gear. Each planetary gear 21 is a standard gear having, for example, the number of teeth z3 = 17 and the shift coefficient x3 = 0.
In the first and second sun gears 19 and 20, the shift coefficient x2 of the second sun gear 20 having a relatively large number of teeth is smaller than the shift coefficient x1 of the first sun gear 19 having a relatively small number of teeth. (X2 <x1).

It is preferable that the number of teeth z1, z2, and z3 of the first and second sun gears 19 and 20 and the planetary gear 21 is in the range of 10 to 30, respectively.
When the number of teeth z1, z2, and z3 is less than 10, respectively, the meshing impact between the planetary gear 21 and the first and second sun gears 19 and 20 corresponding to each other increases and noise increases.

  If the number of teeth z1 and z2 is greater than 30, the speed ratio between the carrier 22 and the second sun gear 20 becomes too large. If the number of teeth of the first sun gear 19 is z1 = 31 and the number of teeth of the second sun gear 20 is z2 = 33, the speed ratio between the carrier 22 and the second sun gear 20 is 1- (z1 / z2). = 1− (31/33) ≈0.0606≈1 / 16.5. Thus, the speed ratio becomes too large, and as a result, the meshing sound between the planetary gear 21 and the second sun gear 20 or the like becomes large.

When the number of teeth z1, z2, and z3 is in the range of 10 to 30, respectively, the absolute value of the difference between the shift coefficients x1 and x2 of the first and second sun gears 19 and 20 is 1.0 to 1. 3 or so.
The absolute values of the dislocation coefficients x1 and x2 of the first and second sun gears 19 and 20 are preferably 1.3 or less, respectively. In the first sun gear 19 that has been normally displaced, if the dislocation coefficient x1 exceeds 1.3, the tooth depth of the tooth portion 52 of the tooth portion forming portion 19a of the first sun gear 19 becomes too low.

  As described above, according to the present embodiment, the following operational effects can be achieved. That is, the tooth portion forming portion 21a of each planetary gear 21 is integrally formed with a single member. Thereby, in order to form the planetary gear 21, for example, a gear member that meshes with the first sun gear and a gear member that meshes with the second sun gear are separately formed, and these gear members are accurately positioned and welded to each other. There is no need for fixing, and as a result, the number of parts and the manufacturing process can be reduced and the manufacturing cost can be significantly reduced.

Further, the configuration for welding and fixing the two gear members is not necessary, and the planetary gear 21 can be downsized. Further, when the planetary gear 21 is assembled, it is not necessary to match the phases of the two gear members with the phases of the corresponding first and second sun gears, and the manufacturing effort can be reduced.
Further, by making the shift coefficients x1 and x2 of the first and second sun gears 19 and 20 having different numbers of teeth z1 and z2 different from each other, an inter-axis distance between the planetary gear 21 and the first sun gear 19, In addition, the inter-axis distance between the planetary gear 21 and the second sun gear 20 can be made to coincide with each other, and smooth meshing can be realized.

  Further, by setting the difference in the number of teeth of the first and second sun gears 19 and 20 to two, two planetary gears 21 can be used, and by distributing the transmission force evenly, each planetary gear mechanism 17 The meshing noises of the gears 19, 20, 21 can be reduced, and the shift coefficients x1, x2 of the first and second sun gears 19, 20 can be optimized, and the first and second sun gears 19, 20 can be optimized. Enough strength can be secured.

  That is, when only one planetary gear is used, the load applied to the planetary gear is large and the meshing sound is increased. If three or more planetary gears are used, the difference in the number of teeth between the first and second sun gears must be three or more, and the shift coefficient of at least one of the first and second sun gears must be increased. As a result, if a positively displaced sun gear (for example, a dislocation coefficient of 1.5) is used, sufficient tooth depth cannot be secured. If a negatively shifted sun gear (for example, a dislocation coefficient of -1.5) is used, It is difficult to secure the original thickness sufficiently.

Further, by using the first and second sun gears 19 and 20 for the planetary gear mechanism 17, the sun gears 19 and 20 can be reduced in the radial direction, and the planetary gear mechanism 17 can be reduced in size.
Furthermore, the first and second sun gears 19 and 20 and the planetary gear 21 have tooth numbers z1, z2 and z3 of 10 or more, respectively, so that the first and second sun gears 19 and 20 corresponding to the planetary gear 21 Noise can be reduced by reducing the impact of each engagement. Further, by setting the number of teeth z1 and z2 to 30 or less, the speed ratio between the carrier 22 and the second sun gear 20 can be prevented from becoming too large. As a result, the carrier 22 is moved by the planetary gear mechanism motor 18. The rotational speed of the carrier 22 when rotating and changing the transmission ratio θ2 / θ1 can be suppressed, and the meshing sound between the planetary gear 21 and the second sun gear 20 can be suppressed.

Furthermore, by setting the absolute value of the dislocation coefficient x1 of the first sun gear 19 to 1.3 or less, it is possible to prevent the tooth depth of the tooth portion 52 from becoming too low in the first sun gear 19 that has been normally displaced, and A sufficient thickness can be secured.
Further, the shift coefficient x2 of the second sun gear 20 having a relatively large number of teeth among the first and second sun gears 19 and 20 is compared with the shift coefficient x1 of the first sun gear 19 having a relatively small number of teeth. (X2 <x1). Thereby, the backlash between the first and second sun gears 19 and 20 and the planetary gear 21 can be reduced.

Further, the rotor 18 a of the planetary gear mechanism motor 18 is arranged coaxially with the steering shaft 3. Thereby, the amount of the planetary gear mechanism motor 18 protruding in the radial direction of the steering shaft 3 can be reduced, and the vehicle steering apparatus 1 can be downsized.
The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.

For example, instead of the second sun gear 20, as shown in FIG. 7, a second sun gear 20A made of a negative shift gear may be used. The shift coefficient of the negative shift gear is lower than both the shift coefficient of the standard gear and the shift coefficient of the positive shift gear. In a negative shift gear, it is said that “the dislocation coefficient increases” as the absolute value of the dislocation coefficient decreases.
The absolute value of the dislocation coefficient x2A of the tooth portion forming portion 20aA of the second sun gear 20A is preferably 1.3 or less. When the absolute value of the dislocation coefficient x2A exceeds 1.3, in the second sun gear 20A subjected to negative dislocation, the thickness of the tooth base of the tooth portion 53 becomes too small to ensure a sufficient thickness. The dislocation coefficient x2A is, for example, -0.2, and the dislocation coefficient x1 of the first sun gear 19 (see FIG. 5) is, for example, 1.0.

As described above, by setting the absolute value of the dislocation coefficient x2A of the second sun gear 20A to 1.3 or less, the thickness of the tooth base of the tooth portion 53 becomes too small in the negatively displaced second sun gear 20A. Can be prevented. The first sun gear 19 may be a standard gear having a displacement coefficient x1 = 0.
In each of the above embodiments, the number of teeth z1 of the first sun gear 19 may be larger than the number of teeth z2 of the second sun gear 20 (z1> z2). In short, it is only necessary that the shift coefficient of the gear having the larger number of teeth among the first and second sun gears 19 and 20 is made small, and both the first and second sun gears 19 and 20 are forwardly shifted. It may be a gear or a negative shift gear, one may be a positive shift gear and the other a negative shift gear, or only one may be a shift gear and the other a standard gear.

  Further, the planetary gear 21 may be a shift gear. Further, instead of the first and second sun gears 19 and 20, annular internal gears may be used.

It is a mimetic diagram showing a schematic structure of a steering device for vehicles concerning one embodiment of the present invention. It is sectional drawing of the principal part of FIG. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing which follows the VV line | wire of FIG. 2, and has shown meshing | engagement with the planetary gear and the 1st sun gear. It is sectional drawing which follows the VI-VI line of FIG. 2, and has shown meshing | engagement with the planetary gear and the 2nd sun gear. It is sectional drawing of the principal part of another embodiment of this invention, and has shown meshing | engagement with a planetary gear and a 2nd sun gear.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering device for vehicles, 2 ... Steering member, 4L, 4R ... Steering wheel, 17 ... Planetary gear mechanism (transmission ratio variable mechanism), 19 ... 1st sun gear (1st gear, sun gear), 20 ... 1st 2 sun gear (second gear, sun gear), 21 ... planetary gear (planetary gear), 21a ... toothed portion, 22 ... carrier, L ... axis, x1, x2A ... dislocation coefficient, z1, z2, z3 ... Number of teeth, θ1 ... steering angle, θ2 ... steering angle, θ2 / θ1 ... transmission ratio.

Claims (6)

A steering shaft including a first portion connected to the steering member and a second portion connected to the steered wheel;
A transmission ratio variable mechanism capable of changing a transmission ratio as a ratio of a turning angle of a steered wheel to a steering angle of a steering member;
A reaction force compensating motor for compensating a steering reaction force of the steering member due to the operation of the transmission ratio variable mechanism,
The transmission ratio variable mechanism includes a planetary gear mechanism that connects the first and second portions so as to be differentially rotatable and is driven by a planetary gear mechanism motor ,
Both the planetary gear mechanism motor and the reaction force compensating motor are arranged coaxially with the steering shaft ,
The planetary gear mechanism includes a first sun gear that is continuous with the first portion, a second sun gear that has an axis that coincides with the axis of the first sun gear, and that is continuous with the second portion, and first and second Two planetary gears that mesh with both of the sun gears, and a carrier that supports the planetary gears so as to rotate and to rotate integrally around the axes of the first and second sun gears,
The carrier is rotationally driven by the planetary gear mechanism motor;
The tooth part forming part of each planetary gear is formed integrally using a single member,
At least one of the first and second sun gears is a shift gear, the shift coefficient (including zero) is different, and the difference in the number of teeth is two . Oite to claim 1, said first portion, said from the steering member and an input member steering torque is inputted, is relatively rotatably coupled through the input member and the torsion bar, the planetary the steering torque An output member that outputs to the gear mechanism . The housing according to claim 2, wherein the housing accommodates the planetary gear mechanism .
The reaction force compensating motor is a vehicle steering apparatus having a rotor that can rotate integrally with the output member of the first portion of the steering shaft, and a stator that surrounds the rotor and is housed in the housing. The vehicle steering apparatus according to any one of claims 1 to 3, wherein the number of teeth of the first sun gear, the second sun gear, and the planetary gear is within a range of 10 to 30, respectively. The vehicle steering apparatus according to any one of claims 1 to 4, wherein the absolute values of the shift coefficients of the first and second sun gears are each 1.3 or less. In any one of claims 1 to 5, addendum modification coefficient of the large sun gear number of teeth of the first and second sun gear, a steering apparatus for a vehicle that is smaller than the addendum modification coefficient of the small sun gear number of teeth .

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