Straddle-type vehicle

Abstract

A straddle-type vehicle is provided with a swing arm (40), a shaft (30) provided at a rear portion of the swing arm (40), a bearing (54) that holds the shaft (30), and a bearing holder (53) that holds the bearing (54) so as to be rotatable with the center position of the bearing (54) eccentric with respect to the swing arm (40), the swing arm (40) is provided with a slit (41) from which the bearing holder (53) is visible from the radial outside of the shaft (30), the bearing holder (53) has a first scale (55) in the circumferential direction around the shaft (30), the swing arm (40) is provided with a second scale (42) around the slit (41) in a manner corresponding to the first scale (55), and the first scale (55) is visible from the slit (41).

Description

Technical Field

[0001] This invention relates to a straddle-type vehicle.

[0002] This application claims priority based on Japanese Patent Application No. 2025-045795, filed on March 19, 2025, the contents of which are incorporated herein by reference. Background Technology

[0003] In the past, in the swing arm structure of a straddle-type electric vehicle, a chain is wound in a loop between the drive sprocket on the internal combustion engine side of the swing arm and the driven sprocket on the rear wheel side. The driving force is transmitted to the rear wheel via the chain. In order to adjust the tension of the chain, as disclosed in Japanese Patent Publication No. 6-102436, a structure with an eccentric mechanism is known. The eccentric mechanism includes: a swing arm; a shaft provided at the rear of the swing arm; a bearing that holds the shaft; and a bearing support that holds the bearing in a rotatable position by eccentrically positioning the bearing's axis relative to the swing arm. Summary of the Invention

[0004] In conventional swingarm designs, the fastening components such as the chain and bearing bracket are located inside the rear wheel. Therefore, without removing the rear wheel, it is difficult to visually inspect these fastening components while performing fastening operations, making it difficult to check the looseness or other condition of the fastening components. Furthermore, while Japanese Patent Publication No. 6-102436 discloses a structure with graduations on the side in the vehicle width direction, the presence of the drive chain and sprockets around the bearing bracket makes it difficult to check the graduations while operating the eccentric mechanism, leaving a challenge for the user in knowing the chain elongation.

[0005] The present invention provides a straddle-type vehicle in which the elongation of the chain can be easily determined.

[0006] To achieve the above objectives, the straddle-type vehicle of the present invention adopts the following structure.

[0007] (1) The present invention is a straddle-type vehicle comprising: a swing arm (40); an axle (30) disposed at the rear of the swing arm (40); a bearing (54) holding the axle (30); and a bearing bracket (53) that holds the bearing (54) rotatably relative to the swing arm (40) at the axial center position of the bearing (54), wherein the swing arm (40) is provided with a slit (41) that makes the bearing bracket (53) visible from the radial outside of the axle (30), the bearing bracket (53) having a first scale (55) in the circumferential direction around the axle (30), and the swing arm (40) having a second scale (42) around the slit (41) in a manner corresponding to the first scale (55), the first scale (55) being visible from the slit (41).

[0008] According to the above-described (1) scheme, a slit is provided in the portion of the swing arm that holds the bearing bracket, so that the first scale set on the bearing bracket aligns with the second scale set around the slit. The rotational position can be visually read from the slit, thereby making it easy to confirm the elongation of the drive transmission components such as the drive chain. Thus, in this invention, the first scale is displayed in the circumferential direction of the bearing bracket, so the scale is easily visible, especially when adjusting the eccentric shaft, and the adjustment operation can be easily performed.

[0009] (2) In the above (1) scheme, the swing arm (40) may also have a fastening part (43) for fixing the bearing bracket (53), and the upper end of the fastening part (43) is located below the lower end of the slit (41).

[0010] According to the above scheme (2), the upper end of the fastener is located below the slit, so that the visual visibility of the slit is not reduced, and the loosening or tightening operation can be easily carried out.

[0011] (3) In the above (2) scheme, the upper end of the fastening part (43) may be located above the central axis of the bearing bracket (53).

[0012] According to the above scheme (3), the upper end of the fastener is located above the central axis of the bearing bracket, thus improving the visual visibility and operability of the fastener.

[0013] (4) In the above (2) scheme, the upper end of the fastening part (43) may be located above the axis of the shaft (30).

[0014] According to the above scheme (4), the upper end of the fastener is located above the axis of the shaft, thus improving the visual visibility and workability of the fastener.

[0015] (5) In the above (1) or (2) scheme, the straddle vehicle may also have a wheel (31), and the slit (41) is located on the inner side of the peripheral end of the wheel (31).

[0016] According to the above scheme (5), the slit is located on the inner side of the wheel's periphery, which can suppress the slit from being exposed to the outside and improve the waterproof and dustproof effect inside the swing arm.

[0017] (6) In the above scheme (1) or (2), the swing arm (40) may have a connecting hole (47) below the bearing bracket (53) that communicates with the interior of the swing arm (40), and the bearing bracket (53) has a through hole (53b) facing the connecting hole (47).

[0018] According to the above scheme (6), the eccentric mechanism can have a drainage function by providing a connecting hole below the swing arm and a through hole below the bearing bracket.

[0019] (7) In the above scheme (1) or (2), the straddle vehicle may also have a brake caliper (34) which is located in a range below the slit (41).

[0020] According to the above scheme (7), the brake caliper is always positioned on the lower side of the slit, thus ensuring the visual confirmation of the slit.

[0021] (8) In the above (2) scheme, the swing arm (40) may also have a thick-walled part (40e) in the circumferential direction, the thick-walled part (40e) is thick in the circumferential direction, and the fastening part (43) is provided in the thick-walled part (40e).

[0022] According to the above-mentioned scheme (8), by increasing the rigidity of the thick-walled portion of the fastening part, performance degradation can be prevented. Moreover, fastening bolts can be installed in the thick-walled portion that has become highly rigid, and the bearing support can be held efficiently and reliably by cooperating with the axial force of the bolts.

[0023] According to the present invention, the elongation of the chain can be easily determined. Attached Figure Description

[0024] Figure 1 This is a right-side view of the motorized two-wheeled vehicle in an embodiment of the present invention.

[0025] Figure 2 It is a three-dimensional view of the rear end of the swing arm of a motorized two-wheeled vehicle, viewed from a diagonal rear.

[0026] Figure 3 yes Figure 2 Enlarged view of the main parts around the rear end of the swing arm shown.

[0027] Figure 4 It is a rear view of the periphery of the rear end of the swing arm, viewed from the rear side.

[0028] Figure 5 It is a top view of the rear end perimeter of the swing arm as seen from above.

[0029] Figure 6 This is a cross-sectional view of the swing arm and bearing bracket viewed from the axle direction.

[0030] Figure 7 It is a top view of the rear end perimeter of the swing arm as seen from above.

[0031] Figure 8 It is a bottom view of the rear end perimeter of the swing arm as seen from below.

[0032] Figure 9 This is a side view of the rear end perimeter of the swing arm, viewed from the right.

[0033] Figure 10 This is a three-dimensional view of the bearing support holding part of the swing arm.

[0034] Symbol explanation: 1. Motorized two-wheeled vehicles (horseback riding vehicles) 2. Front wheels 3 Rear wheels 3a Rear wheel axle 10 Frame 11 Internal Combustion Engine 23 Pivot 30 axis 31 wheels 31a Wheel Rim 34 Brake calipers 35 Brake bracket 40 swing arm 40a Rear end 40b Front end 40d peripheral wall 40e Thick-walled section 40A Arm 40B Bearing Support Retention Section 41 Slit 42 Second Scale 43 Fastening parts 43a Opening 43b Upper end 46 convex part 47 Connecting holes 50 Rear wheel support mechanism 51 Driven sprocket 53 Bearing bracket 53a Peripheral 53b Circumferential groove (through hole) 54 bearing 55 First scale 61 Drive chain Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. It should be noted that in the various embodiments described below, common parts are labeled with the same symbols. Unless otherwise specified, the directions such as front, back, left, and right in the following description are the same as the directions in the vehicle described below. Furthermore, in the figures used in the following description, arrows indicating the front of the vehicle (FR), the left side of the vehicle (LH), the top of the vehicle (UP), and the left and right center lines of the vehicle body (CL) are shown in appropriate locations.

[0036] In this embodiment, "middle" refers not only to the center between the two ends of the object, but also to the inner range between the two ends of the object. In the following description, the motorcycle is in a parked state with its body not tilted to the left or right and upright at a steering angle of 0 degrees, and is in an unloaded state on a horizontal plane.

[0037] <Vehicle as a whole>

[0038] Figure 1 A motorized two-wheeled vehicle 1 is shown as an example of a straddle-type vehicle. Figure 1 This is a right-side view of motorized two-wheeled vehicle 1.

[0039] like Figure 1 As shown, the motorized two-wheeled vehicle 1 is a vehicle in which an internal combustion engine 11 is supported on a frame 10, a front fork 12 capable of steering via a handlebar 21 is supported at the front end of the frame 10, and a rear wheel 3 is supported via a rear wheel support mechanism 50 (see reference). Figure 2 and Figure 3 The support is a rotatable swing arm 40 located at the rear of the frame 10.

[0040] The motorized two-wheeled vehicle 1 is a straddle-type vehicle in which the passenger straddles the seat 14, which is located above the rear of the frame 10.

[0041] The steering system components, including the handlebars 21 and the front wheel 2, are pivotally supported on the head tube 15 formed at the front end of the frame 10. The frame 10 includes: a head tube 15 disposed at the front end of the frame 10; a main frame 16 extending rearward from the head tube 15; a descending frame 17 extending rearward and downward from the front end of the frame 10; a center frame 18 extending downward from the rear end of the main frame 16; and a pair of left and right seat frames 19 extending rearward from the upper part of the center frame 18.

[0042] The front fork 12 is supported by the head tube 15 and is capable of turning left and right. The handlebar 21 for steering is mounted on the upper end of the front fork 12. The front wheel 2 is supported by an axle 2a located at the lower end of the front fork 12.

[0043] Internal Combustion Engine

[0044] The internal combustion engine 11 is located below the main frame 16 and is positioned between the down frame 17 and the center frame 18 in the longitudinal direction of the vehicle, and is fixed to the frame 10.

[0045] The internal combustion engine 11 includes a crankcase (not shown), a crankshaft rotatably supported in the crankcase, and a cylinder section 24 extending upward from the upper part of the front of the crankcase. The crankcase is fixed to the frame 10. The cylinder section 24 includes a cylinder 24a extending upward from the upper surface of the crankcase, a cylinder head 24b coupled to the upper surface of the cylinder 24a, and a cylinder head cover 24c covering the upper surface of the cylinder head 24b. The internal combustion engine 11 is a multi-cylinder internal combustion engine in which multiple cylinders are arranged axially along the crankshaft. The crankshaft extends horizontally in the vehicle width direction (left-right direction), and the cylinders are arranged in the vehicle width direction.

[0046] The rear of the crankcase houses the transmission (not shown). The output of the internal combustion engine 11 is transmitted to the rear wheel 3 via a drive chain 61 that connects the aforementioned transmission and the rear wheel 3.

[0047] The exhaust pipe 22 of the internal combustion engine 11 extends downward from the front surface of the cylinder head 24b and extends rearward through the underside of the internal combustion engine 11.

[0048] Seat 14 is positioned above seat frame 19 and is supported by seat frame 19.

[0049] The fuel tank 26 is positioned above the internal combustion engine 11 between the seat 14 and the head tube 15 and is supported by the main frame 16.

[0050] Rear wheel support mechanism

[0051] The rear wheel support mechanism 50 is located on the left side of the rear wheel 3. The rear wheel support mechanism 50 includes: a driven sprocket 51 that engages with the rear end of a drive chain 61, which serves as a drive transmission member, and is fixed to the axle of the rear wheel 3 (hereinafter referred to as the rear wheel axle 3a); a housing 52 that houses the driven sprocket 51; and a bearing bracket 53 that has a bearing 54 that holds the rear wheel axle 3a in a rotatable position. The front end of the drive chain 61 is connected to a drive sprocket (not shown) that outputs power generated by the internal combustion engine 11.

[0052] like Figure 2 As shown, the rear wheel axle 3a (axle 30) is hollow, and the rear wheel 31, which serves as the drive wheel, is supported by bearing 54 to allow for free rotation. Figure 4 As shown, a driven sprocket 51 is bolted to one side (left side) of the wheel 31 in the vehicle width direction, and a circular plate 32 is integrally provided on the other side (right side). A tire is embedded in the rim 31a of the wheel 31.

[0053] like Figure 1 As shown, the drive chain 61 is wound in a loop between the drive sprocket on the side of the internal combustion engine 11 and the driven sprocket 51 on the side of the rear wheel 3, so the power of the internal combustion engine 11 is transmitted to the rear wheel 3 via the drive chain 61.

[0054] The brake bracket 35, equipped with brake calipers 34, can move forward and backward in response to the rotation of the eccentric mechanism.

[0055] <Bearing bracket>

[0056] like Figure 6 As shown, the bearing bracket 53 is cylindrical and housed within the bearing bracket holding portion 40B of the swing arm 40 (described later). The bearing bracket 53 is fitted in such a way that it can rotate about the cylindrical shaft of the bearing bracket holding portion 40B of the swing arm 40. The bearing bracket 53 holds the bearing 54 rotatably by eccentrically positioning the axial center C1 of the bearing 54 relative to the swing arm 40. A circular axle insertion hole is provided at the axial center C1 of the bearing bracket 53, and the rear wheel axle 3a is rotatably supported in this axle insertion hole via a bearing.

[0057] like Figure 2 and Figure 3As shown, a first scale 55 is displayed on the circumferential surface 53a of the bearing bracket 53, along the circumferential direction surrounding the rear wheel axle 3a. The first scale 55 is an indicator etched on the circumferential surface 53a of the bearing bracket 53, protruding from the slit 41 of the swing arm 40 (described later). The first scale 55 is displayed in an area slightly inclined rearward from the uppermost part of the circumferential surface 53a. The first scale 55 is displayed at predetermined intervals or in different colors relative to the circumferential direction of the swing arm 40, and the position of this scale can be used to determine the rotational position of the bearing bracket 53, i.e., the position of the eccentric axis C1. Thus, by visually confirming the first scale 55, the elongation state of the chain can be easily identified when adjusting the tension of the drive chain 61.

[0058] <Arm Swing 40>

[0059] like Figure 1 As shown, the swing arm 40 is cylindrical, extending longitudinally. The front end 40b of the swing arm 40 is supported by a pivot 23, which is supported by the lower part of the central frame 18. The swing arm 40 swings up and down about the pivot 23. The swing arm 40 is rotatably supported on the frame 10 via the pivot 23, and extends rearward from the pivot 23 to support the rear wheel 3 so that it can rotate. The swing arm 40 is mounted on the internal combustion engine 11 that drives the rear wheel 3.

[0060] like Figure 4 and Figure 5 As shown, the swing arm 40 has: an arm portion 40A extending from the pivot 23 toward the rear wheel support mechanism 50; and a bearing bracket retaining portion 40B disposed in front of the rear wheel 3 and having an opening for receiving the rear wheel support mechanism 50. The swing arm 40 integrally forms the arm portion 40A and the bearing bracket retaining portion 40B by means of the same component.

[0061] The arm portion 40A has a pair of rear suspension support portions 40Aa and 40Ab that stand upright from both sides in the vehicle width direction. The portion of the inner side of the arm portion 40A in the vehicle width direction that faces the tire of the rear wheel 3 is arc-shaped and smoothly connected to the rear wall of the bearing bracket holding portion 40B in the rear end 40a of the control arm 40. The outer side portions of the pair of arm portions 40A in the vehicle width direction are symmetrical in shape to the inner side portions in the vehicle width direction, and are arc-shaped and smoothly connected to the rear wall of the bearing bracket holding portion 40B. The cross section of the arm portion 40A orthogonal (intersecting) with the length direction is a closed ring.

[0062] The bearing bracket holding portion 40B has openings on both sides in the vehicle width direction. The bearing bracket holding portion 40B is generally cylindrical in shape with the cylindrical shaft facing in the direction along the rear wheel axle 3a. The bearing bracket 53 of the rear wheel support mechanism 50 is housed inside the bearing bracket holding portion 40B. The rear wheel support mechanism 50 is provided with a bearing 54 that supports the rear wheel axle 3a so that it can rotate.

[0063] like Figure 1 As shown, the rear wheel 3 is supported on the rear wheel axle 3a located at the rear end 40a of the control arm 40. The rear suspension 25 is mounted between the rear suspension support portions 40Aa and 40Ab of the control arm 40 and the frame 10.

[0064] A rear wheel support mechanism 50 is installed at the rear end 40a of the swing arm 40, which supports the rear wheel axle 3a so that it can rotate. The rear wheel axle 3a is equivalent to the axle 30.

[0065] <Detailed Structure of the Swing Arm>

[0066] The swing arm 40 has a slit 41 that makes the bearing bracket 53 visible from the radially outer side of the rear wheel axle 3a. For example... Figures 2-6 As shown, slit 41 penetrates the bearing support retaining portion 40B. Slit 41 is located in the middle of the bearing support retaining portion 40B in the machine width direction, and is an elongated hole shape with an upward opening extending from the upper end of the bearing support retaining portion 40B toward a position obliquely rearward and upward. Slit 41 is formed by a pair of slit side edges 41a, a slit front edge 41b, and a slit rear edge 41c extending in the circumferential direction.

[0067] like Figure 2 and Figure 3 As shown, the slit 41 is formed at a position where the first mark 55, displayed on the circumferential surface 53a of the bearing bracket 53, is visible from the outside of the slit 41. That is, the first mark 55 is exposed on the inside of the slit 41. Therefore, the occupant can easily identify the slit 41 and the first mark 55 by visual inspection from the rear of the vehicle. Therefore, when adjusting the drive chain 61 (refer to...) Figure 1 and Figure 2 When the tension of the drive chain 61 is known, its looseness or other states can be confirmed.

[0068] In the bearing bracket holding portion 40B, a second scale 42 is provided around the slit 41 in a manner corresponding to the first scale 55. The second scale 42 is displayed on the peripheral wall surface 40d on the right side of the slit 41 in the vehicle width direction. When adjusting the rotational position of the bearing bracket 53 relative to the rocker arm 40, the adjustment can be performed while confirming the first scale 55 visible from the slit 41 and the second scale 42 displayed on the peripheral wall surface 40d of the bearing bracket holding portion 40B.

[0069] like Figure 7 As shown, the slit 41 is located in the vehicle width direction at a position inside the rim 31a, which is closer to the periphery of the wheel 31.

[0070] In addition, such as Figure 8 and Figure 9 As shown, the brake caliper 34 is located in the area below the slit 41.

[0071] like Figure 6and Figure 10 As shown, the opening end of the slit 41 has a protrusion 46 for close contact with the circumferential surface 53a of the bearing bracket 53. Although the protrusion 46 is thinned along the inner circumference at the central portion in the width direction of the inner surface of the circumferential wall surface 40d of the bearing bracket holding portion 40B, it is continuous with the circumferential wall surface 40d. The slit 41 becomes an upward opening communicating with the interior of the bearing bracket holding portion 40B. Therefore, by providing the protrusion 46, the protruding end 46a of the protrusion 46 can be made to be in close contact with the circumferential surface 53a of the bearing bracket 53. Thus, the close contact between the opening end of the slit 41 and the circumferential surface 53a of the bearing bracket 53 can prevent the intrusion of water and dust into the fastening connection (encircling surface) between the rocker arm 40 and the bearing bracket 53, and can suppress meshing and instability.

[0072] like Figure 3 , Figure 4 and Figure 6 As shown, the rocker arm 40 has a fastening portion 43 for fixing the bearing bracket 53. The fastening portion 43 is provided on the rear end side of the bearing bracket holding portion 40B at the rear end 40a of the rocker arm 40. The fastening portion 43 has an opening 43a that divides the bearing bracket holding portion 40B vertically, and the upper piece 43A and the lower piece 43B, which are vertically opposed, are fastened to each other by bolts 44 through the opening 43a. The upper piece 43A and the lower piece 43B protrude radially outward from the peripheral wall surface 43c of the bearing bracket holding portion 40B, respectively. The bearing bracket holding portion 40B has a structure that can be reduced in diameter by the groove 43a. A female thread is formed in the lower piece 43B, and a bolt hole is formed in the upper piece 43A, so that the bolt 44 passes through the bolt hole of the upper piece 43A from the top and engages with the female thread of the lower piece 43B, thereby fastening the upper piece 43A and the lower piece 43B.

[0073] In adjusting the tension of the drive chain 61, for example, an example is given where the rear wheel axle 3a, which is in its forwardmost position, is moved backward a predetermined distance. Figure 6 As shown, after loosening the bolt 44 of the fastening part 43 to release the fastening of the swing arm 40 to the bearing bracket 53, the bearing bracket 53 is rotated clockwise by a specified angle, for example, by using a wrench.

[0074] By this rotation, the axle center (axle position C1) of the rear wheel axle 3a rotates clockwise by the same predetermined angle around the center O of the bearing bracket 53's spool shaft, thereby adjusting the axle distance between the drive sprocket and the driven sprocket 51 (not shown) by a predetermined amount in the front-rear direction. That is, the tension of the drive chain 61 can be adjusted.

[0075] like Figure 2 and Figure 3As shown, the bearing bracket 53 is rotated and aligned using the first scale 55 shown on the circumferential surface 53a of the bearing bracket 53 and the second scale 42 shown on the swing arm 40 as references. Furthermore, after the adjustment of the drive chain 61 is completed, the bolts 44 of the fastening part 43 are tightened at this position. The bearing bracket 53 is then positioned and held in place with it fastened to the swing arm 40.

[0076] like Figure 6 As shown, the upper end 43b (height position of symbol H2) of the upper piece 43A of the fastening part 43 is positioned below the rear edge 41c (height position of symbol H1) of the slit 41. The upper end 43b of the fastening part 43 is positioned above the central axis (center O of the cylinder shaft) of the bearing bracket 53. Furthermore, the upper end 43b of the fastening part 43 is positioned above the axle center position C1 of the rear wheel axle 3a.

[0077] like Figure 3 As shown, the peripheral wall surface 40d in the rear end 40a (bearing bracket holding part 40B) of the swing arm 40 has a thick-walled part 40e that is thick-walled in the region extending circumferentially on both sides of the slit 41 in the width direction. Fastening parts 43 are respectively provided on the thick-walled parts 40e on the left and right sides.

[0078] like Figure 6 and Figure 8 As shown, the bearing support holding portion 40B of the swing arm 40 has a communicating hole 47 communicating with the interior of the swing arm below the bearing support 53. The bearing support 53 has a circumferential groove 53b (through hole) facing the communicating hole 47. The communicating hole 47 is not connected to the slit 41, thus ensuring the rigidity of the swing arm 40. In this way, by having a structure that separates the communicating hole 47 from the slit 41 while retaining a connection portion, water entering from the slit 41 can be guided to the communicating hole 47 and discharged.

[0079] As described above, the motorized two-wheeled vehicle 1 in the above embodiment includes a swing arm 40, an axle 30 disposed at the rear of the swing arm 40, a bearing 54 holding the axle 30, and a bearing bracket 53 that holds the bearing 54 in a rotatable manner by offsetting the axial center position of the bearing 54 relative to the swing arm 40. The swing arm 40 is provided with a slit 41 that makes the bearing bracket 53 visible from the radially outer side of the axle 30. The bearing bracket 53 has a first graduation 55 in the circumferential direction around the axle 30. The swing arm 40 has a second graduation 42 around the slit 41 in a manner corresponding to the first graduation 55. The first graduation 55 is visible from the slit 41.

[0080] According to this embodiment of the motorized two-wheeled vehicle 1, a slit 41 is provided in the portion of the swing arm 40 that holds the bearing bracket 53, so that a first scale 55 provided on the bearing bracket 53 aligns with a second scale 42 provided around the slit 41. The rotational position can be read visually from the slit 41, thereby making it easy to confirm the elongation of drive transmission components such as the drive chain 61. Thus, in this embodiment, the first scale 55 is displayed in the circumferential direction of the bearing bracket 53, so the scale is easily visible, especially when adjusting the eccentric shaft, and adjustment operations can be easily performed.

[0081] In the aforementioned motorized two-wheeled vehicle 1, the swing arm 40 has a fastening part 43 for fixing the bearing bracket 53. The upper end 43b of the fastening part 43 is located below the lower end (rear edge 41c of the slit) of the slit 41.

[0082] According to this structure, the upper end 43b of the fastening part 43 is positioned below the slit 41, thereby ensuring that the visual visibility of the slit 41 is not reduced, and thus the loosening or tightening operation can be easily performed.

[0083] In the aforementioned motorized two-wheeled vehicle 1, the upper end 43b of the fastening part 43 is located above the central axis of the bearing bracket 53.

[0084] According to this structure, the upper end 43b of the fastener 43 is positioned above the central axis of the bearing bracket 53, thus improving the visual visibility and operability of the fastener 43.

[0085] In the aforementioned motorized two-wheeled vehicle 1, the upper end 43b of the fastening part 43 is located above the axle center of the rear wheel axle 3a.

[0086] According to this structure, the upper end 43b of the fastening part 43 is positioned above the axle center position C1 of the rear wheel axle 3a, thus improving the visual visibility and operability of the fastening part 43.

[0087] The motorized two-wheeled vehicle 1 described above also has a wheel 31. The slit 41 can be located inside the rim (rim 31a) of the wheel 31.

[0088] According to this structure, the slit 41 is located inside the rim 31 (the peripheral end of the wheel 31), which can suppress the slit 41 from being exposed to the outside and improve the waterproof and dustproof effect inside the swing arm 40.

[0089] In the aforementioned motorized two-wheeled vehicle 1, the swing arm 40 may also have a communication hole 47 below the bearing bracket 53 that communicates with the interior of the swing arm 40, and the bearing bracket 53 may have a circumferential groove 53b facing the communication hole 47.

[0090] According to this structure, the eccentric mechanism can have a drainage function by means of the connecting hole 47 provided below the swing arm 40 and the circumferential groove 53b provided below the bearing bracket 53.

[0091] In the aforementioned motorized two-wheeled vehicle 1, it may also include a brake caliper 34, which is located in a region below the slit 41.

[0092] According to this structure, the brake caliper 34 is always positioned on the lower side of the slit 41, thus ensuring the visual visibility of the slit 41.

[0093] Furthermore, the motorized two-wheeled vehicle 1 in the above embodiment has a thick-walled portion 40e in the circumferential direction of the swing arm 40, which is thick in the circumferential direction. A fastening portion 43 is provided in the thick-walled portion 40e.

[0094] According to this structure, by increasing the rigidity of the thick-walled portion 40e of the fastening portion 43, performance degradation can be prevented. Moreover, a fastening bolt 44 can be arranged in the thick-walled portion 40e, which has become highly rigid, and the bearing bracket 53 can be held efficiently and reliably by engaging with the axial force of the bolt.

[0095] This invention is not limited to the embodiments described above. For example, the structure of the embodiments can also be applied to straddle-type vehicles other than motorized two-wheeled vehicles. The straddle-type vehicles include all vehicles where the driver straddles the vehicle, including not only motorized two-wheeled vehicles (including bicycles and small motorcycles with a prime mover), but also three-wheeled (including vehicles with two front wheels and one rear wheel, in addition to those with one front wheel and two rear wheels) or four-wheeled vehicles (such as four-wheeled buggies). Furthermore, it includes not only small motorcycles with a straddle space, but also vehicles with a straddle section. It can also be applied to vehicles whose prime mover includes an electric motor.

[0096] It can also be applied to various types of reciprocating engines, such as single-cylinder engines, parallel or V-type multi-cylinder engines, and longitudinally mounted engines with the crankshaft along the front-rear direction of the vehicle.

[0097] Furthermore, the structure described above is an example of the present invention, and the constituent elements of the embodiment can be replaced with well-known constituent elements, etc., and various changes can be made without departing from the spirit of the present invention.

Claims

1. A straddle-type vehicle, wherein, The motorcycle-type vehicle has the following features: Swing arm (40); A shaft (30) is disposed at the rear of the swing arm (40); The bearing (54) holds the shaft (30); and A bearing bracket (53) is provided, which eccentrically positions the bearing (54) relative to the rocker arm (40) to hold the bearing (54) in a rotatable position. The swing arm (40) is provided with a slit (41) that makes the bearing bracket (53) visible from the radial outside of the shaft (30). The bearing bracket (53) has a first scale (55) in the circumferential direction around the shaft (30). The swing arm (40) has a second scale (42) around the slit (41) in a manner corresponding to the first scale (55). The first scale (55) is visible from the slit (41).

2. The straddle-type vehicle according to claim 1, wherein, The swing arm (40) has a fastening part (43) for fixing the bearing bracket (53). The upper end of the fastening part (43) is positioned below the lower end of the slit (41).

3. The straddle-type vehicle according to claim 2, wherein, The upper end of the fastening part (43) is positioned above the central axis of the bearing bracket (53).

4. The straddle-type vehicle according to claim 2, wherein, The upper end of the fastening part (43) is positioned above the axis of the shaft (30).

5. The straddle-type vehicle according to claim 1, wherein, The straddle-type vehicle also has wheels (31). The slit (41) is located inside the periphery of the wheel (31).

6. The straddle-type vehicle according to claim 1, wherein, The swing arm (40) has a communication hole (47) below the bearing bracket (53) that communicates with the interior of the swing arm (40). The bearing bracket (53) has a through hole (53b) facing the connecting hole (47).

7. The straddle-type vehicle according to claim 1, wherein, The straddle-type vehicle also has brake calipers (34). The brake caliper (34) is positioned below the slit (41).

8. The straddle-type vehicle according to claim 2, wherein, The swing arm (40) has a thick-walled portion (40e) in the circumferential direction, and the thick-walled portion (40e) is thick in the circumferential direction. The fastening part (43) is provided in the thick-walled portion (40e).

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