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EP-4737288-A1 - LEAN VEHICLE

EP4737288A1EP 4737288 A1EP4737288 A1EP 4737288A1EP-4737288-A1

Abstract

A rod coupling 45 of a lean vehicle is disposed radially apart from a second steering axis L2 and is angularly displaced about the second steering axis L2 integrally with a steering shaft. A left rod 51 is link-coupled to the rod coupling 45 and a left front wheel, and angularly displaces the left front wheel about a left front wheel pivot axis in accordance with an angular displacement of the steering shaft 43. The same applies to a right side. The left front wheel pivot axis and a right front wheel pivot axis are both inclined to extend upward toward a rear side. A rod arrangement plane S1 is a horizontal plane extending along a horizontal direction, or is an inclined plane that is inclined to extend upward toward the rear side.

Inventors

  • NAGAO, KOKI
  • ISHII, HIROSHI
  • NARUMI, Tadashi
  • INABA, Taichi

Assignees

  • KAWASAKI MOTORS, LTD.

Dates

Publication Date
20260506
Application Date
20251028

Claims (11)

  1. A lean vehicle (1) configured to travel in a lean state relative to a road surface, the lean vehicle (1) comprising: a seat (9) on which a driver is seated; a body frame (2) which includes a seat post (10) that supports the seat (9) and extends in an up-down direction; a parallel link mechanism (20) which is link-coupled to the body frame (2) and includes a left arm (23), a right arm (24), an upper arm (21), and a lower arm (22), the left arm (23) and the right arm (24) extending parallel to the seat post (10); a left front wheel (3a) which is supported by the left arm (23) to be angularly displaceable about a left front wheel pivot axis (L7) of the left arm (23); a right front wheel (3b) which is supported by the right arm (24) to be angularly displaceable about a right front wheel pivot axis (L10) of the right arm (24); a steering shaft (43) which is supported by the body frame (2) and is angularly displaced about a steering axis (L2) in response to a steering force from the driver; a rod coupling (45) which is disposed radially apart from the steering axis (L2) and is angularly displaced about the steering axis (L2) integrally with the steering shaft (43); a left rod (51) which is link-coupled to the rod coupling (45) and the left front wheel (3a), and which angularly displaces the left front wheel (3a) about the left front wheel pivot axis (L7) in accordance with an angular displacement of the steering shaft (43); and a right rod (61) which is link-coupled to the rod coupling (45) and the right front wheel (3b), and which angularly displaces the right front wheel (3b) about the right front wheel pivot axis (L10) in accordance with the angular displacement of the steering shaft (43), wherein the left front wheel pivot axis (L7) and the right front wheel pivot axis (L10) are both inclined to extend upward toward a rear side, and an axis of the left rod (51) and an axis of the right rod (61) extend parallel to either the upper arm (21) or the lower arm (22), or are inclined to extend upward toward a vehicle-widthwise inner side in an upright state of the vehicle.
  2. The lean vehicle (1) according to claim 1, wherein the axis of the left rod (51) and the axis of the right rod (61) extend parallel to either the upper arm (21) or the lower arm (22).
  3. The lean vehicle (1) according to claim 1 or 2, wherein the axis of the left rod (51) and the axis of the right rod (61) are inclined to extend upward toward the vehicle-widthwise inner side in the upright state of the vehicle.
  4. The lean vehicle (1) according to any one of claims 1 to 3, wherein the parallel link mechanism (20) is located in front of the steering shaft (43), and the rod coupling (45) is located behind the steering shaft (43).
  5. The lean vehicle (1) according to claim 2, wherein the rod coupling (45) is located above a lower end portion of the lower arm (22).
  6. The lean vehicle (1) according to any one of claims 1 to 5, wherein when viewed in a direction along the steering axis (L2), a distance from the steering axis (L2) to the left front wheel pivot axis (L7) is equal to a length of the left rod (51), a distance from the steering axis (L2) to the right front wheel pivot axis (L10) is equal to a length of the right rod (61), a distance from the steering axis (L2) to a proximal end (51a) of the left rod (51), the proximal end (51a) being an end on a side of the rod coupling (45), is equal to a distance from the left front wheel pivot axis (L7) to a distal end (51b) of the left rod (51), the distal end (51b) being an end on a side of the left front wheel (3a), and a distance from the steering axis (L2) to a proximal end (61a) of the right rod (61) is equal to a distance from the right front wheel pivot axis (L10) to a distal end (61b) of the right rod (61).
  7. The lean vehicle (1) according to claim 2, wherein the rod coupling (45) is connected to a lower end portion of the steering shaft (43), and a portion of the left rod (51) and the right rod (61) that is coupled to the rod coupling (45) is located closer to the lower arm (22) than to a center position of the parallel link mechanism (20) in the up-down direction.
  8. The lean vehicle (1) according to claim 2, wherein a link coupling structure between the left arm (23) and the left front wheel (3a), and a link coupling structure between the right arm (24) and the right front wheel (3b) each include, in the upright state of the vehicle, a structure that is angularly displaceable about a vertical axis (L5, L8) parallel to a vertical direction, and a structure that is angularly displaceable about a longitudinal axis (L6, L9) parallel to a front-rear direction.
  9. The lean vehicle (1) according to any one of claims 1 to 8, wherein a coupling structure between at least one of the left rod (51) and the right rod (61) and the rod coupling (45) includes a ball joint.
  10. The lean vehicle (1) according to any one of claims 1 to 9, further comprising: a handlebar shaft (41) configured to be angularly displaced coaxially with a steering handlebar (5); a steering mechanism (6) configured to transmit the steering force transmitted to the handlebar shaft (41) to the steering shaft (43); and an accommodation section (90) that is disposed, in a side view, in a range including between an axial position of the handlebar shaft (41) and an axial position of the steering shaft (43), and that accommodates a load (100).
  11. A lean vehicle (1) configured to travel in a lean state relative to a road surface, the lean vehicle (1) comprising: a seat (9) on which a driver is seated; a body frame (2) which includes a seat post (10) that supports the seat (9) and extends in an up-down direction; a parallel link mechanism (20) which is link-coupled to the body frame (2) and includes a left arm (23), a right arm (24), an upper arm (21), and a lower arm (22), the left arm (23) and the right arm (24) extending parallel to the seat post (10); a left front wheel (3a) which is supported by the left arm (23) to be angularly displaceable about a left front wheel pivot axis (L7) of the left arm (23); a right front wheel (3b) which is supported by the right arm (24) to be angularly displaceable about a right front wheel pivot axis (L10) of the right arm (24); a steering shaft (43) which is supported by the body frame (2) and is angularly displaced about a steering axis (L2) in response to a steering force from the driver; a rod coupling (45) which is disposed radially apart from the steering axis (L2) and is angularly displaced about the steering axis (L2) integrally with the steering shaft (43); a left rod (51) which is link-coupled to the rod coupling (45) and the left front wheel (3a), and which angularly displaces the left front wheel (3a) about the left front wheel pivot axis (L7) in accordance with an angular displacement of the steering shaft (43); and a right rod (61) which is link-coupled to the rod coupling (45) and the right front wheel (3b), and which angularly displaces the right front wheel (3b) about the right front wheel pivot axis (L10) in accordance with the angular displacement of the steering shaft (43), wherein the left front wheel pivot axis (L7) and the right front wheel pivot axis (L10) are both inclined to extend upward toward a rear side, and a rod arrangement plane (S1, S3), which is a virtual plane that overlaps the rod coupling (45) and through which an axis of the left rod (51) and an axis of the right rod (61) pass, is an inclined plane that is inclined to extend upward toward the rear side in an upright state of the vehicle.

Description

Technical Field The present application relates to a lean vehicle configured to travel in a lean state relative to a road surface. Background Art Patent Literature 1 is Japanese Patent No. 7413181. In the lean vehicle of Patent Literature 1, as a steering drive arm rotates, left and right tie rods push and pull left and right front wheels to change steering angles of the left and right front wheels. Summary of Invention In the lean vehicle of Patent Literature 1, a steering drive arm is inclined downward toward a rear side from a steering transmission shaft in a side view. In this type of layout, a force that counteracts a restoring force by a self-steering torque is likely to be generated for reasons described later. As a result, running stability at a low speed or at a start of travel is reduced. The present application has been made in view of the above circumstances, and a main object thereof is to provide a configuration that facilitates enhancement of running stability at a low speed or at a start of travel in a lean vehicle configured to travel in a lean state relative to a road surface. Solution to Problem Problems to be solved by the present application are as described above. Hereinafter, solutions to the problems and advantageous effects thereof will be described. According to a first aspect of the present invention, a lean vehicle configured as follows is provided. That is, the lean vehicle is configured to travel in a lean state relative to a road surface. The lean vehicle comprises a seat, a body frame, a parallel link mechanism, a left front wheel, a right front wheel, a steering shaft, a rod coupling, a left rod, and a right rod. A driver is seated on the seat. The body frame includes a seat post that supports the seat and extends in an up-down direction. The parallel link mechanism is link-coupled to the body frame, and includes a left arm, a right arm, an upper arm, and a lower arm. The parallel link mechanism forms a parallel link in a front view of the vehicle. When the vehicle is in an upright state, the left arm and the right arm extend parallel to the seat post. The left front wheel is supported by the left arm to be angularly displaceable about a left front wheel pivot axis of the left arm. The right front wheel is supported by the right arm to be angularly displaceable about a right front wheel pivot axis of the right arm. The steering shaft is supported by the body frame and is angularly displaced about a steering axis in response to a steering force from the driver. The rod coupling is disposed radially apart from the steering axis and is angularly displaced about the steering axis integrally with the steering shaft. The left rod is link-coupled to the rod coupling and the left front wheel, and angularly displaces the left front wheel about the left front wheel pivot axis in accordance with an angular displacement of the steering shaft. The right rod is link-coupled to the rod coupling and the right front wheel, and angularly displaces the right front wheel about the right front wheel pivot axis in accordance with the angular displacement of the steering shaft. The left front wheel pivot axis and the right front wheel pivot axis are both inclined to extend upward toward a rear side. An axis of the left rod and an axis of the right rod extend parallel to either the upper arm or the lower arm, or are inclined to extend upward toward a vehicle-widthwise inner side in an upright state of the vehicle. According to a second aspect of the present invention, a lean vehicle configured as follows is provided. That is, the lean vehicle is configured to travel in a lean state relative to a road surface. The lean vehicle comprises a seat, a body frame, a parallel link mechanism, a left front wheel, a right front wheel, a steering shaft, a rod coupling, a left rod, and a right rod. A driver is seated on the seat. The body frame includes a seat post that supports the seat and extends in an up-down direction. The parallel link mechanism is link-coupled to the body frame, and includes a left arm, a right arm, an upper arm, and a lower arm, the left arm and the right arm extending parallel to the seat post. The left front wheel is supported by the left arm to be angularly displaceable about a left front wheel pivot axis of the left arm. The right front wheel is supported by the right arm to be angularly displaceable about a right front wheel pivot axis of the right arm. The steering shaft is supported by the body frame and is angularly displaced about a steering axis in response to a steering force from the driver. The rod coupling is disposed radially apart from the steering axis and is angularly displaced about the steering axis integrally with the steering shaft. The left rod is link-coupled to the rod coupling and the left front wheel, and angularly displaces the left front wheel about the left front wheel pivot axis in accordance with an angular displacement of the steering shaft. The right ro