JP5640929B2 - Wheel steering device - Google Patents

Description

  The present invention relates to a wheel turning device, and more particularly to a wheel turning device that rotates an output shaft that is linked to a turning operation of a rear wheel by rotation of an input shaft that is linked to a turning operation of a front wheel.

  Conventionally, a vehicle steering device has been proposed in which a rotation operation by a steering wheel is transmitted to a rear wheel steering means by rotation of a link member to steer the rear wheel together with the front wheel (see, for example, Patent Document 1).

Japanese Examined Patent Publication No. Sho 62-030955

  With the technology described in the above-mentioned patent document, the rear wheel can be steered in the same direction as the front wheel when the steering angle is small, and the rear wheel can be steered in the opposite direction to the front wheel when the steering angle is large. It is. However, the input / output characteristics realized by the technique described in the above-mentioned patent document are those described in FIG. 4 of the above-mentioned patent document, and it is difficult to realize other input / output characteristics. For this reason, in such a wheel turning device, it is difficult to adjust the steering characteristics when the steering angle is small and large.

  Accordingly, the present invention has been made to solve the above-described problems, and its purpose is to rotate an output shaft that is linked to the steering operation of the rear wheels by the rotation of the input shaft that is linked to the steering operation of the front wheels. It is to make the input / output characteristics appropriate.

  In order to solve the above-described problems, a wheel turning device according to an aspect of the present invention includes an input shaft-side lever that rotates according to rotation of an input shaft that is linked to a turning operation of a front wheel, and each of the input shaft-side levers. And a plurality of output shaft side levers that rotate the output shaft interlocked with the steering operation of the rear wheels. The input shaft side lever switches the output shaft side lever to be engaged among the plurality of output shaft side levers according to the rotation angle of the input shaft.

  According to this aspect, the input / output characteristics indicating the rotation of the output shaft relative to the rotation of the input shaft when the input shaft-side lever is engaged can be appropriately set for each output shaft-side lever. For this reason, compared with the case where there is one output shaft side lever, the degree of freedom in setting the input / output characteristics can be increased, and the driver's uncomfortable feeling due to the turning of the rear wheels can be suppressed.

  The plurality of output shaft side levers includes a first output shaft side lever engaged with the input shaft side lever when the front wheel is steered to the right, and the input shaft when the front wheel is steered to the left. A second output shaft side lever engaged with the side lever. According to this aspect, the input / output characteristics can be set easily. For example, when the same input / output characteristics are realized when the front wheel is steered to the right and when it is steered to the left, the first output shaft side lever, the second output shaft side lever, and other parts are shared. It becomes possible to do. For this reason, the types of parts can be reduced, and parts management can be facilitated.

  When the first output shaft side lever is engaged with the input shaft side lever, the rear wheel is also steered to the right when the front wheel is steered to a right smaller than a predetermined angle, and to the right greater than the predetermined angle. When the vehicle is steered, the output shaft is rotated so that the rear wheel is steered to the left, and when the second output shaft side lever is engaged with the input shaft side lever, the front wheel is smaller than a predetermined angle and left The output shaft may be rotated so that the rear wheels are also steered to the left when steered to the left, and the rear wheels are steered to the right when steered to the left greater than the predetermined angle. According to this aspect, it is possible to appropriately set the steering angle range of the front wheels that cause the rear wheels to steer in the same direction both when the front wheels are steered to the left and when the front wheels are steered to the right. it can.

  According to the present invention, the input / output characteristics when rotating the output shaft interlocked with the steering operation of the rear wheels by the rotation of the input shaft interlocking with the steering operation of the front wheels can be made appropriate.

(A) is a front view which shows typically the structure of the wheel steering apparatus which concerns on this embodiment, (b) is a top view of the wheel steering apparatus which concerns on this embodiment. It is a figure which shows the structure of the input / output conversion mechanism which concerns on this embodiment in detail. It is PP sectional drawing of FIG. It is a figure which shows the state of an input-output conversion mechanism when a front wheel is steered to the left at a small angle. It is a figure which shows the state of an input-output conversion mechanism when a front wheel is steered to the left largely to a limit angle.

Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.
Fig.1 (a) is a front view which shows typically the structure of the wheel steering apparatus 10 which concerns on this embodiment, FIG.1 (b) is a top view of the wheel steering apparatus 10 which concerns on this embodiment. is there. The wheel turning device 10 is interposed between the front wheels 12 and the rear wheels 14 and the steering shaft 16, and steers the front wheels 12 and the rear wheels 14 according to the steering of the steering shaft 16.

  In a vehicle equipped with the wheel steering device 10, the front wheel 12 is one in the front center of the vehicle, the rear wheel 14 is one in the rear center, the right wheel is one on the right side of the vehicle, the left wheel is one on the left side of the vehicle, A total of four wheels are arranged in a diamond shape. Of course, the vehicle on which the wheel steering device 10 is mounted is not limited to such a vehicle.

  The wheel steering device 10 includes a front wheel steering mechanism 18, a rear wheel steering mechanism 20, and a transmission mechanism 22. The front wheel steering mechanism 18 steers the front wheels 12 according to the steering angle of the steering shaft 16. Since the configuration of the front wheel steering mechanism 18 is known, the description thereof is omitted. The rear wheel steering mechanism 20 is connected to the steering shaft 16 via the transmission mechanism 22, and steers the rear wheel 14 according to the steering angle of the steering shaft 16.

  The rear wheel steering mechanism 20 includes an input shaft 30, an output shaft 32, and an input / output conversion mechanism 34. The input shaft 30 is connected to the steering shaft 16 by the transmission mechanism 22 so as to rotate at the same angle as the steering angle of the steering shaft 16. Therefore, the input shaft 30 is interlocked with the turning operation of the front wheels 12. When the speed transmission ratio between the input shaft 30 and the output shaft 32 is 1, that is, when the input shaft 30 and the output shaft 32 are connected to each other so as to rotate at the same angle, the input shaft 30 and the output shaft 32 12 and the rear wheel 14 are connected to the front wheel 12 and the output shaft 32, respectively, so that they are steered at the same angle.

  The input / output conversion mechanism 34 connects the input shaft 30 and the output shaft 32 so that a difference is generated between the input shaft 30 and the output shaft 32. Specifically, in the input / output conversion mechanism 34, the rear wheel 14 is the same as the front wheel 12 in a predetermined range where the steering angle of the steering shaft 16 is small, that is, in a range where the turning angle of the front wheel 12 is greater than 0 ° and smaller than the predetermined angle. The input shaft 30 and the output shaft 32 are connected so as to steer in the direction. On the other hand, in the input / output conversion mechanism 34, the rear wheel 14 is opposite to the front wheel 12 until the steering angle of the steering shaft 16 is large, that is, until the turning angle of the front wheel 12 exceeds the predetermined angle and reaches the turning limit angle. The input shaft 30 and the output shaft 32 are connected so as to steer in the direction.

  Thus, when the turning angle of the front wheel 12 is small, the vehicle can be driven stably without changing the attitude of the vehicle by turning the rear wheel 14 in the same direction as the front wheel 12. On the other hand, when the turning angle of the front wheel 12 is large, the small turning can be realized by turning the rear wheel 14 in the opposite direction to the front wheel 12.

  FIG. 2 is a diagram showing in detail the configuration of the input / output conversion mechanism 34 according to the present embodiment. 3 is a cross-sectional view taken along the line PP in FIG. The configuration of the input / output conversion mechanism 34 will be described below with reference to both FIG. 2 and FIG.

  The input / output conversion mechanism 34 includes a bracket 50, an input shaft side lever 54, a pin 56, a first output shaft side lever 60, a first gear 62, a second output shaft side lever 64, a second gear 66, and an output gear 68. Have. The bracket 50 is formed in a shape obtained by bending a plate-like member into a U shape. A circular insertion hole is provided coaxially in each of the two upper plate portions of the bracket 50 facing each other, and the input shaft 30 and the output shaft 32 are rotatably inserted into the insertion hole.

  One end of the input shaft side lever 54 is fixed to the input shaft 30 so as to extend perpendicular to the extending direction of the input shaft 30. Therefore, the input shaft side lever 54 rotates according to the rotation of the input shaft 30. A pin 56 is fixed to the other end of the input shaft side lever 54 so as to extend in parallel with the input shaft 30.

  An output gear 68 is coaxially fixed to the output shaft 32. The first gear 62 and the output gear 68 are engaged with the output gear 68. One end of the first output shaft side lever 60 is fixed to the first gear 62 so as to extend perpendicular to the axial direction of the first gear 62. One end of the second output shaft side lever 64 is fixed to the second gear 66 so as to extend perpendicular to the axial direction of the second gear 66.

  The first output shaft side lever 60 has a groove 60a extending from the front end toward the rear end. The groove 60 a has substantially the same width as the outer diameter of the pin 56. The second output shaft side lever 64 has a groove 64a extending from the front end toward the rear end. The groove 64a also has substantially the same width as the outer diameter of the pin 56. In the present embodiment, when the input shaft 30 is rotated, the pins 56 are on the grooves 60a of the first output shaft side lever 60 and the second output shaft side except when the front wheels 12 and the rear wheels 14 are not steered. Each of the input shaft side lever 54, the first output shaft side lever 60, and the second output shaft side lever 64 is disposed so as to selectively engage with one of the grooves 64a of the lever 64.

  As described above, the first output shaft side lever 60 rotates the output shaft 32 when the groove 60a is engaged with the input shaft side lever 54 and rotated. Further, the second output shaft side lever 64 rotates the output shaft 32 by the groove 64 a being engaged with the input shaft side lever 54 and rotated.

  In the present embodiment, the input shaft side lever 54 switches the output shaft side lever to be engaged among the first output shaft side lever 60 and the second output shaft side lever 64 according to the rotation angle of the input shaft 30. Specifically, the first output shaft side lever 60 is engaged with the input shaft side lever 54 when the front wheel 12 is steered to the right. The second output shaft side lever 64 is engaged with the input shaft side lever 54 when the front wheel 12 is steered to the left. When the torque transmission path is the same by making the torque transmission path from the input shaft 30 to the output shaft 32 different between when the front wheel 12 is steered to the left and when it is steered to the left. As compared with the above, it is possible to increase the degree of freedom in setting the input / output characteristics that are the rotational characteristics of the output shaft 32 with respect to the rotation of the input shaft 30. For this reason, the output shaft 32 can be more appropriately rotated with respect to the rotation of the input shaft 30, and the uncomfortable feeling given to the driver during steering can be suppressed.

  FIG. 3 shows a neutral state in which the steering wheel has not been steered since the vehicle is traveling straight, and the front wheels 12 and the rear wheels 14 are not steered. At this time, the pin 56 is engaged with both the vicinity of the opening of the groove 60 a of the first output shaft side lever 60 and the vicinity of the opening of the groove 64 a of the second output shaft side lever 64.

  In the input / output conversion mechanism 34, the center of the input shaft side lever 54 is set in the neutral state so that the rear wheel 14 is steered in the same manner when the front wheel 12 is steered to the right and when it is steered to the left. The input / output conversion mechanism 34 is provided symmetrically with respect to the vertical plane. Therefore, the second gear 66 and the output gear 68 have the same shape, and the first output shaft side lever 60 has the same shape as the second output shaft side lever 64. Note that these may have different shapes. Hereinafter, the extending direction of the input shaft side lever 54 in the neutral state is defined as the input side neutral position np1, and the extending direction of the first output shaft side lever 60 in the neutral state is defined as the output side neutral position np2.

  Furthermore, in the present embodiment, there are two output shaft side levers, the first output shaft side lever 60 and the second output shaft side lever 64, but the number of output shaft side levers is not limited to two. For example, a plurality of output shaft side levers may be provided for left turning so that the engagement with the input shaft side lever 54 is switched halfway when the front wheel 12 is turned to the left. Further, for example, a plurality of output shaft side levers may be provided for right turning so that the engagement with the input shaft side lever 54 is switched halfway when the front wheel 12 is turned to the right. .

  FIG. 4 is a diagram illustrating a state of the input / output conversion mechanism 34 when the front wheel 12 is steered to the left at a small angle. FIG. 4 also shows a cross-sectional view taken along the line PP in FIG. Note that the state of the input / output conversion mechanism 34 when the front wheel 12 is steered to the right is obtained by inverting the input / output conversion mechanism 34 shown in FIG. 4 around the input-side neutral position np1. Hereinafter, the description when the front wheel 12 is steered to the left will be omitted, and the description when the front wheel 12 is steered to the right will be omitted.

  When the front wheel 12 is steered to the right and the input shaft 30 rotates to the left, the pin 56 slides in the groove 60a toward the heel while maintaining engagement with the groove 60a of the first output shaft side lever 60. Move. Thereby, the first output shaft side lever 60 rotates to the left by a minute angle. Further, the output gear 68 rotates to the right opposite to the first gear 62, and the output shaft 32 fixed coaxially with the first gear 62 also rotates to the left.

  At this time, the engagement between the groove 64a of the second output shaft side lever 64 and the pin 56 is released. When the input shaft side lever 54 rotates, the second output shaft side lever 64 also rotates. However, when the steering of the front wheels 12 is released and the state returns to the neutral state, the second output shaft side lever 64 also returns to the initial position. The groove 64a is engaged with the pin 56 in the vicinity of the opening.

  FIG. 4 shows a state in which the extending direction of the input shaft side lever 54 and the extending direction of the first output shaft side lever 60 are perpendicular to each other. Thus, the first gear 62 rotates to the left in the same manner as the input shaft 30 until the input shaft side lever 54 becomes perpendicular to the first output shaft side lever 60. Therefore, the output shaft 32 rotates to the right opposite to the input shaft 30. The front wheel steering mechanism 18 is configured such that the front wheel 12 is steered to the left when the input shaft 30 rotates to the left. The rear wheel steering mechanism 20 is configured such that when the output shaft 32 rotates to the right, the rear wheel 14 is steered to the left. Therefore, in the state shown in FIG. 4, both the front wheel 12 and the rear wheel 14 are steered to the left.

  The rotation angle of the input shaft side lever 54 from the input side neutral position np1 at this time is defined as an input angle θa1, and the rotation angle of the first output shaft side lever 60 from the output side neutral position np2 is defined as an output angle θb1. The maximum angle at which the output shaft 32 rotates to the right is a value obtained by multiplying the output angle θb1 by the gear ratio between the first gear 62 and the output gear 68. Specifically, if the number of teeth of the output gear 68 is N1 and the number of teeth of the first gear 62 is N2, the rotation angle of the output shaft 32 from the neutral state is an output angle θb1 × N2 / N1.

  FIG. 5 is a diagram illustrating the state of the input / output conversion mechanism 34 when the front wheel 12 is steered to the left to the limit angle. FIG. 5 also shows a cross-sectional view taken along the line PP in FIG.

  When the front wheel 12 is steered at a large angle and the input shaft 30 rotates to the right at the large input angle θa1, the pin 56 is shown in FIG. 4 while maintaining the engagement with the groove 60a of the first output shaft side lever 60. It slides further toward the ridge in the groove 60a than ever. Accordingly, the first output shaft side lever 60 rotates to the right from the state shown in FIG. Therefore, the output shaft 32 rotates to the left like the input shaft 30.

  The rear wheel steering mechanism 20 is configured such that when the output shaft 32 rotates to the left, the rear wheel 14 is steered to the right. Therefore, until the state shown in FIG. 4 is changed to the state shown in FIG. 5, the front wheel 12 is steered to the left, but the rear wheel 14 is steered to the right opposite to the front wheel 12.

  As shown in FIG. 5, the rotation angle of the input shaft side lever 54 from the input side neutral position np1 when the front wheel 12 is steered to the maximum is the input angle θa2, and the first output shaft from the output side neutral position np2 The rotation angle of the side lever 60 is defined as an output angle θb12. The maximum angle at which the output shaft 32 rotates to the left from the neutral state is a value obtained by multiplying the output angle θb2 by the gear ratio between the first gear 62 and the output gear 68. Specifically, the rotation angle of the output shaft 32 from the neutral state is the output angle θb2 × N2 / N1.

  In the present embodiment, the front wheel steering mechanism 18 is provided so that the input shaft 30 rotates by the input angle θa2 when the front wheels 12 are steered by 90 °. On the other hand, the rear wheel steering mechanism 20 is provided so that the rear wheel 14 is steered in the reverse direction of 90 ° when the output shaft 32 rotates by the output angle θb2 × N2 / N1. Therefore, when the front wheel 12 is steered 90 °, the rear wheel 14 is steered 90 ° in the reverse direction.

  As described above, when the first output shaft side lever 60 is engaged with the input shaft side lever 54, when the front wheel 12 is steered to the right smaller than a predetermined angle, the rear wheel is steered to the right, and the predetermined angle is set. When the vehicle is steered to the right more greatly, the output shaft 32 is rotated so that the rear wheel is steered to the left. On the other hand, when the second output shaft side lever 64 is engaged with the input shaft side lever 54, when the front wheel 12 is steered to the left smaller than a predetermined angle, the rear wheel is steered to the left and larger than the predetermined angle. When the vehicle is steered to the left, the output shaft 32 is rotated so that the rear wheels are steered to the right.

  In this way, by switching a plurality of links according to the steering direction, the link setting freedom can be increased. Therefore, the degree of freedom in setting the input / output characteristics indicating the rotation of the output shaft 32 relative to the rotation of the input shaft 30 can be increased, and the driver's discomfort with respect to the steering of the rear wheels can be suppressed.

  The present invention is not limited to the above-described embodiment, and an appropriate combination of the elements of this embodiment is also effective as an embodiment of the present invention. Various modifications such as various design changes can be added to the present embodiment based on the knowledge of those skilled in the art, and the embodiments with such modifications can be included in the scope of the present invention.

  10 wheel steering device, 12 front wheel, 14 rear wheel, 16 steering shaft, 18 front wheel steering mechanism, 20 rear wheel steering mechanism, 22 transmission mechanism, 30 input shaft, 32 output shaft, 34 input / output conversion mechanism, 50 bracket, 54 input shaft side lever, 56 pins, 60 first output shaft side lever, 60a groove, 62 first gear, 64 second output shaft side lever, 64a groove, 66 second gear, 68 output gear.

Claims (3)

An input shaft side lever that rotates in accordance with the rotation of the input shaft linked to the steering operation of the front wheels,
A plurality of output shaft side levers that rotate the output shaft in conjunction with the steering operation of the rear wheels by each engaging and rotating with the input shaft side lever;
With
The wheel turning device according to claim 1, wherein the input shaft side lever switches an output shaft side lever to be engaged among the plurality of output shaft side levers according to a rotation angle of the input shaft. The plurality of output shaft side levers are:
A first output shaft side lever engaged with the input shaft side lever when the front wheel is steered to the right;
A second output shaft side lever engaged with the input shaft side lever when the front wheel is steered to the left;
The wheel steering apparatus according to claim 1, comprising: When the first output shaft side lever is engaged with the input shaft side lever, the rear wheel is also steered to the right when the front wheel is steered to a right smaller than a predetermined angle, and to the right greater than the predetermined angle. Rotate the output shaft so that the rear wheels are steered to the left when steered,
When the second output shaft side lever is engaged with the input shaft side lever, when the front wheel is steered to the left smaller than a predetermined angle, the rear wheel is steered to the left, and to the left greater than the predetermined angle. The wheel turning device according to claim 2, wherein when the vehicle is steered, the output shaft is rotated so that the rear wheel is steered to the right.

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