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EP-4737290-A1 - STRADDLED VEHICLE

EP4737290A1EP 4737290 A1EP4737290 A1EP 4737290A1EP-4737290-A1

Abstract

A straddled vehicle (1) includes: a vehicle body frame (2); a first shaft (A1) extending in a width direction (Y) and supported by the vehicle body frame (2); a rotating member (19) supported by the first shaft (A1) and rotating about the first shaft (A1); a pivot shaft (P) supported by the rotating member (19); a rear arm (9) supported by the pivot shaft (P); a rear axle (R) supported by the rear arm (9); a rear wheel (11) supported by the rear axle (R); and a coupling mechanism (18) coupled to the vehicle body frame (2), the rotating member (19), and the rear arm (9), wherein, a distance between an axis (a1) of the first shaft (A1) and an axis (p) of the pivot shaft (P) is defined as a first distance (E1), and the first distance (E1) is 50 mm or more.

Inventors

  • TAKANO, KAZUHISA

Assignees

  • Yamaha Hatsudoki Kabushiki Kaisha

Dates

Publication Date
20260506
Application Date
20251002

Claims (15)

  1. A straddled vehicle (1) comprising: a vehicle body frame (2); a first shaft (A1) supported by the vehicle body frame (2) and extending in a width direction (Y) of the straddled vehicle (1); a rotating member (19) supported by the first shaft (A1) and configured to rotate about the first shaft (A1) with respect to the vehicle body frame (2); a pivot shaft (P) supported by the rotating member (19) and extending in the width direction (Y) of the straddled vehicle (1); a rear arm (9) supported by the pivot shaft (P) and configured to rotate about the pivot shaft (P) with respect to the rotating member (19) with regard to an up-down direction (Z) of the straddled vehicle (1); a rear axle (R) supported by the rear arm (9) and extending in the width direction (Y) of the straddled vehicle (1); a rear wheel (11) arranged at a rear side with regard to the front-rear direction (X) of the straddled vehicle (1) and supported by the rear axle (R) ; and a coupling mechanism (18) coupled to the vehicle body frame (2), the rotating member (19), and the rear arm (9), wherein in a side view of the straddled vehicle (1), a distance between an axis (a1) of the first shaft (A1) and an axis (p) of the pivot shaft (P) is defined as a first distance (E1), and the first distance (E1) is 50 mm or more.
  2. The straddled vehicle (1) according to claim 1, wherein a range in which the pivot shaft (P) is movable is defined as a pivot movable range (G), and the pivot movable range (G) is limited to an area more forward than the first shaft (A1) with regard to the front-rear direction (X) of the straddled vehicle (1).
  3. The straddled vehicle (1) according to claim 2, further comprising a drive shaft (D) that outputs power, wherein the drive shaft (D) is disposed more forward than the pivot shaft (P) with regard to the front-rear direction (X) of the straddled vehicle (1), a virtual line connecting the drive shaft (D) and the first shaft (A1) is defined as a virtual line (Q), and the pivot movable range (G) extends from a position higher than the virtual line (Q) to a position lower than the virtual line (Q) with regard to the up-down direction (Z) of the straddled vehicle (1) in a side view of the straddled vehicle (1).
  4. The straddled vehicle (1) according to claim 3, wherein a distance between the drive shaft (D) and the rear axle (R) is defined as a distance (E5b), a distance between the drive shaft (D) and the rear axle (R) is defined as a distance (E5a) (E5c), and the distance (E5b) when the pivot shaft (P) is located on the virtual line (Q) in a side view of the straddled vehicle (1) is shorter than the distance (E5a) (E5c) when the pivot shaft (P) is located higher than the virtual line (Q) or lower than the virtual line (Q) with regard to the up-down direction (Z) of the straddled vehicle (1) in a side view of the straddled vehicle.
  5. The straddled vehicle (1) according to claim 2 or 3, wherein a length of the pivot movable range (G) in the up-down direction (Z) of the straddled vehicle (1) is defined as a first length (PA1), a length of the pivot movable range (G) in the front-rear direction (X) of the straddled vehicle (1) is defined as a second length (PA2), and the second length (PA2) is shorter than the first length (PA1).
  6. The straddled vehicle (1) according to claim 1 or 2, wherein the rotating member (19) has an arm shape extending from the first shaft (A1) to the pivot shaft (P) in a side view of the straddled vehicle (1).
  7. The straddled vehicle (1) according to claim 1 or 2, wherein the rotating member (19) includes a rear end (19B) supported by the first shaft (A1), and a front end (19A) supporting the pivot shaft (P).
  8. The straddled vehicle (1) according to claim 1 or 2, wherein in a side view of the straddled vehicle (1), a distance between the axis (p) of the pivot shaft (P) and an axis (r) of the rear axle (R) is defined as a second distance (E2), and the second distance (E2) is equal to or smaller than 15 times the first distance (E1).
  9. The straddled vehicle (1) according to claim 8, wherein the second distance (E2) is 750 mm or less.
  10. The straddled vehicle (1) according to claim 1 or 2, wherein when the rear axle (R) moves upward with respect to the vehicle body frame (2) with regard to the up-down direction (Z) of the straddled vehicle (1), the coupling mechanism (18) moves the pivot shaft (P) upward with respect to the vehicle body frame (2) with regard to the up-down direction (Z) of the straddled vehicle (1), and when the rear axle (R) moves downward with respect to the vehicle body frame (2) with regard to the up-down direction (Z) of the straddled vehicle (1), the coupling mechanism (18) moves the pivot shaft (P) downward with respect to the vehicle body frame (2) with regard to the up-down direction (Z) of the straddled vehicle (1).
  11. The straddled vehicle (1) according to claim 1 or 2, wherein when the rear axle (R) rotates clockwise about the pivot shaft (P) in a left side view of the straddled vehicle, the pivot shaft (P) rotates counterclockwise about the first shaft (A1), and when the rear axle (R) rotates counterclockwise about the pivot shaft (P) in the left side view of the straddled vehicle, the pivot shaft (P) rotates clockwise about the first shaft (A1).
  12. The straddled vehicle (1) according to claim 1 or 2, wherein the coupling mechanism (18) includes: a second shaft (31) supported by the vehicle body frame (2) and extending in the width direction (Y) of the straddled vehicle (1); a first link member (32) coupled to the second shaft; a third shaft (33) supported by the first link member (32) and extending in the width direction (Y) of the straddled vehicle (1); a fourth shaft (34) supported by the rear arm (9) and extending in the width direction (Y) of the straddled vehicle (1); a second link member (35) coupled to the third shaft (33) and the fourth shaft (34); a fifth shaft (36) supported by the first link member (32) and extending in the width direction (Y) of the straddled vehicle (1); a sixth shaft (37) supported by the rotating member (19) and extending in the width direction (Y) of the straddled vehicle (1); and a third link member (38) coupled to the fifth shaft (36) and the sixth shaft (37).
  13. The straddled vehicle (1) according to claim 12, wherein in a side view of the straddled vehicle (1), a distance between the axis (p) of the pivot shaft (P) and an axis (37z) of the sixth shaft (37) is defined as a third distance (E3), in the side view of the straddled vehicle (1), a distance between the axis (37z) of the sixth shaft (37) and the axis (a1) of the first shaft (A1) is defined as a fourth distance (E4), and the third distance (E3) is shorter than the fourth distance (E4).
  14. The straddled vehicle (1) according to claim 12, wherein the sixth shaft (37) is disposed more rearward than the pivot shaft (P) and more forward than the first shaft (A1) with regard to the front-rear direction (X) of the straddled vehicle (1).
  15. The straddled vehicle (1) according to claim 12, wherein a range in which the sixth shaft (37) is movable is defined as a sixth shaft movable range (H), and the sixth shaft movable range (H) is limited to an area more forward than the first shaft (A1) with regard to the front-rear direction (X) of the straddled vehicle (1).

Description

The present invention relates to a straddled vehicle. A straddled vehicle disclosed in JP 2014-181007 A includes a vehicle body frame, a pivot shaft, a rear arm, a rear axle, and a rear wheel. The pivot shaft is supported by the vehicle body frame. The rear arm is supported by the pivot shaft. The rear arm rotates about a pivot shaft with respect to the vehicle body frame. The rear axle is supported by the rear arm. The rear wheel is supported by the rear axle. When the rear arm rotates about the pivot shaft with respect to the vehicle body frame, an angle of the rear arm changes. When the angle of the rear arm changes, the state of the straddled vehicle or the behavior of the straddled vehicle changes. Therefore, when the change in the angle of the rear arm is small, it is easy for a driver to drive the straddled vehicle. Here, the angle of the rear arm is, for example, an angle between an axis of the rear arm and a reference line in a side view of the straddled vehicle. The axis of the rear arm is a virtual line connecting an axis of the pivot shaft and an axis of the rear axle in the side view of the straddled vehicle. For example, the reference line may be defined by the vehicle body frame. Alternatively, the reference line may be defined by a road surface with which the rear wheel comes into contact. The longer the rear arm, the smaller the change in angle of the rear arm. However, it may be difficult to increase the length of the rear arm. It is the an object of the present invention is to provide a straddled vehicle that can easily reduce a change in angle of a rear arm. According to the present invention said object is solved by a straddled vehicle having the features of the independent claim 1. Preferred embodiments are laid down in the dependent claims. First, it has been studied that a straddled vehicle includes a movable mechanism. The movable mechanism moves the pivot shaft with respect to the vehicle body frame. For example, the movable mechanism includes a first shaft, a rotating member, and a coupling mechanism. The first shaft is supported by the vehicle body frame. The rotating member is supported by the first shaft. The rotating member is configured to rotate about the first shaft with respect to the vehicle body frame. The pivot shaft is supported by the rotating member. The rear arm is supported by the pivot shaft. The rear arm is configured to rotate about the pivot shaft with respect to the rotating member. The coupling mechanism is coupled to the rear arm, the rotating member, and the vehicle body frame. When the rear axle moves with respect to the vehicle body frame, the rear arm rotates about the pivot shaft with respect to the rotating member, and the coupling mechanism rotates the rotating member about the first shaft with respect to the vehicle body frame. When the rotating member rotates about the first shaft with respect to the vehicle body frame, the pivot shaft rotates about the first shaft with respect to the vehicle body frame. In summary, when the rear axle moves with respect to the vehicle body frame, the pivot shaft moves with respect to the vehicle body frame. Therefore, it is easy to reduce the change in the angle of the rear arm. However, it has been found that a new problem occurs in a case where the straddled vehicle includes the movable mechanism. The rotation of the pivot shaft about the first shaft with respect to the vehicle body frame is decomposed into a first movement of the pivot shaft and a second movement of the pivot shaft. The first movement of the pivot shaft is a movement of the pivot shaft with respect to the vehicle body frame in an up-down direction of the straddled vehicle. The second movement of the pivot shaft is a movement of the pivot shaft with respect to the vehicle body frame in a front-rear direction of the straddled vehicle. A new problem is that the second movement of the pivot shaft may become significantly greater when the pivot shaft moves with respect to the vehicle body frame. For example, the straddled vehicle includes a drive shaft and a drive mechanism. The drive shaft outputs power. The drive shaft is coupled to, for example, an engine or a transmission. The drive mechanism transmits power from the drive shaft to the rear wheel. The drive mechanism includes, for example, a chain, a belt, or a drive shaft. A length of the drive mechanism is substantially equal to a distance between the rear axle and the drive shaft. When the pivot shaft moves with respect to the vehicle body frame, the distance between the drive shaft and the rear axle may vary significantly. For example, when an amount of the second movement of the pivot shaft is significantly large, the distance between the rear axle and the drive shaft may vary significantly. Therefore, it may be difficult for the drive mechanism to transmit power from the drive shaft to the rear wheel. For example, in a case where the drive mechanism includes the chain, movement of the pivot