Motorcycle rear suspension structure

Abstract

To provide a rear suspension structure of a motor cycle that contributes to downsizing of the motor cycle.SOLUTION: A rear suspension structure 4 of a motor cycle 1 includes: a swing arm 6 that is connected to a vehicle body frame 2 in a front end swingably via a pivot 5a, is suspended to the vehicle body frame 2 via a rear cushion 7, and supports a rear wheel 3 in a rear end; a link member 8 that is connected to the vehicle body frame 2 and is connected to a lower end of the rear cushion 7; and a vehicle height adjustment device 9 provided between the swing arm 6 and the link member 8. The vehicle height adjustment device 9 includes: a body part 91 that extends and contracts in a front and rear direction to adjust the vehicle height; and a free piston part 92 that is provided in an upper part in the body part 91 and acts on the body part 91 to enable the body part 91 to extend and contract.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rear suspension structure for a motorcycle. [Background technology]

[0002] Conventionally, a rear suspension structure for a motorcycle is known that includes a swing arm that supports the rear wheel, a rear cushion that suspends the swing arm via a link member, and a vehicle height adjustment device that is provided between the swing arm and the link member (see, for example, Patent Document 1). The vehicle height adjustment device has, for example, a main body that adjusts the vehicle height by expanding and contracting, and a free piston that is provided in front of the main body and acts on the main body to expand and contract the main body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-018476 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional rear suspension structures, the free piston portion of the vehicle height adjustment device is located in front of the main body portion, which increases the length of the vehicle height adjustment device in the fore-and-aft direction, hindering the miniaturization of motorcycles.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a rear suspension structure for a motorcycle that contributes to the miniaturization of motorcycles. [Means for solving the problem]

[0006] (1) A rear suspension structure (for example, rear suspension structure 4 described later) of a motorcycle (for example, motorcycle 1 described later) according to the present invention includes a swing arm (for example, swing arm 6 described later) that is swingably connected at its front end to a body frame (for example, body frame 2 described later) via a swing shaft (for example, pivot 5a described later), is suspended from the body frame via a rear cushion (for example, rear cushion 7 described later), and supports a rear wheel (for example, rear wheel 3 described later) at its rear end, a link member (for example, link member 8 described later) that is connected to the body frame and to a lower end of the rear cushion, and a vehicle height adjustment device (for example, vehicle height adjustment device 9 described later) that is provided between the swing arm and the link member, and the vehicle height adjustment device has a main body portion (for example, main body portion 91 described later) that adjusts the vehicle height by extending and contracting in the fore-and-aft direction, and a free piston portion (for example, free piston portion 92 described later) that is provided above the main body portion and acts on the main body portion to allow the main body portion to extend and contract.

[0007] According to the motorcycle rear suspension structure of the invention (1), the free piston portion of the height adjustable device is provided above the main body portion. This allows the front-to-rear length of the height adjustable device to be shorter than conventional devices, thereby shortening the front-to-rear length of the motorcycle and making the motorcycle more compact. Consequently, the motorcycle rear suspension structure of the invention (1) allows the motorcycle to be made more compact, improving the handling stability of the motorcycle.

[0008] (2) In the motorcycle rear suspension structure according to the invention of (1), the free piston portion may be provided at a position overlapping the link member in a side view.

[0009] According to the motorcycle rear suspension structure of the invention (2), the free piston portion of the vehicle height adjustment device is positioned so as to overlap with the link member in a side view. This allows the rear suspension structure to be made more compact, and therefore the motorcycle to be made more compact. Furthermore, the motorcycle rear suspension structure of the invention (2) contributes to the effective use of space, improving the layout flexibility of the motorcycle.

[0010] (3) In the motorcycle rear suspension structure according to the invention of (2), the link member may have a shape that allows the free piston portion to be housed therein.

[0011] According to the rear suspension structure for a motorcycle according to the third aspect of the present invention, the link member has a shape that can accommodate the free piston portion therein. This prevents the free piston portion of the vehicle height adjustment device from being exposed to the outside, thereby improving the appearance of the motorcycle. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a rear suspension structure for a motorcycle that contributes to the miniaturization of motorcycles. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a side view showing a rear suspension structure of a motorcycle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view showing the structure around the vehicle height adjusting device. [Figure 3] FIG. 3 is a cross-sectional view taken along the arrow III-III direction in FIG. 2. [Figure 4] FIG. 2 is a vertical cross-sectional view showing the structure of the vehicle height adjusting device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0015] First, a rear suspension structure 4 for a motorcycle 1 according to one embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a side view showing the rear suspension structure 4 for the motorcycle 1, more specifically, a view of the rear suspension structure 4 for the motorcycle 1 as viewed from the left side. Figure 2 is a side view showing the periphery of a height-adjustable device 9, more specifically, a view of the periphery of the height-adjustable device 9 as viewed from the left side. Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. Figure 4 is a vertical cross-sectional view showing the structure of the height-adjustable device 9. For convenience, only the height-adjustable device 9 is shown in Figure 3, and Figure 4 corresponds to a cross-sectional view taken along the line IV-IV in Figure 3.

[0016] The motorcycle 1 of this embodiment is an off-road type motorcycle. As shown in Fig. 1, the motorcycle 1 includes a body frame 2, a rear suspension structure 4 that suspends a rear wheel 3, and the like.

[0017] The body frame 2 is formed by joining multiple types of steel materials together by welding or the like. This body frame 2 includes a pair of left and right pivot frames 5, a cross member (not shown), and the like. The pair of left and right pivot frames 5 are disposed at the rear end of the body frame 2. The cross member (not shown) connects the upper parts of the pair of left and right pivot frames 5.

[0018] As shown in FIGS. 1 and 2, the rear suspension structure 4 includes a pair of left and right swing arms 6, a rear cushion 7, a link member 8, and a vehicle height adjuster 9.

[0019] The pair of left and right swing arms 6 are swingably connected at their respective front ends to a pair of left and right pivot frames 5 on the body frame 2 via pivots (swing shafts) 5a. The pair of left and right swing arms 6 extend in the fore-and-aft direction of the motorcycle 1 and are suspended from the body frame 2 via a rear cushion 7. The pair of left and right swing arms 6 also support the rear wheel 3 at their rear ends.

[0020] The rear cushion 7 is connected to a cross member (not shown) of the body frame 2 at a position above the pivot 5a, and has a lower end connected to a link member 8 via a swing shaft 8b so as to be swingable.

[0021] The link member 8 shown in Figures 1 to 3 is provided in a position forward and below the swing arm 6. This link member 8 interconnects the pivot frame 5 of the body frame 2, the rear cushion 7, and the vehicle height adjustment device 9. Specifically, the link member 8 is swingably connected to the pivot frame 5 of the body frame 2 via a swing shaft 8a, and is swingably connected to the lower end of the rear cushion 7 via a swing shaft 8b. The link member 8 is swingably connected to the vehicle height adjustment device 9 via a swing shaft 8c, and is thereby indirectly connected to the swing arm 6.

[0022] Furthermore, the link member 8 has two link plates 81, 82 that are generally triangular in side view and are connected by swing shafts 8a, 8b, 8c that are located at the vertices of the generally triangular shape. The link member 8 and a free piston portion 92 of the vehicle height adjustment device 9, which will be described later, are disposed in positions that overlap each other in side view. The link member 8 has a shape that can accommodate the free piston portion 92 therein, and the free piston portion 92 is accommodated between the two link plates 81, 82. Specifically, both of the two link plates 81, 82 have a shape that bulges outward, and the free piston portion 92 is disposed in the bulging portion.

[0023] 1 and 2 is a device for adjusting the vehicle height of the motorcycle 1, and is provided between the swing arm 6 and the link member 8. The vehicle height adjusting device 9 is swingably connected to the link member 8 via a swing shaft 8c, and is swingably connected to the pair of left and right swing arms 6 via a swing shaft 6a.

[0024] Specifically, the vehicle height adjustment device 9 has a main body 91 and a free piston 92. The main body 91 adjusts the vehicle height by expanding and contracting in the fore-and-aft direction. The free piston 92 is provided at an upper, front portion of the main body 91 and acts on the main body 91 to expand and contract the main body 91. The vehicle height adjustment device 9 swings the swing arm 6 upward as the main body 91 expands in the fore-and-aft direction, thereby lowering the vehicle height. The vehicle height adjustment device 9 also swings the swing arm 6 downward as the main body 91 contracts in the fore-and-aft direction, thereby raising the vehicle height.

[0025] As shown in FIG. 4, the main body 91 includes a cylinder 93, a piston 94, a piston rod 95, a coil spring 96, and hydraulic oil 97.

[0026] The front end of the cylinder 93 is connected to the link member 8 via a swing shaft 8c so as to be able to swing. The cylinder 93 is divided by a piston 94 into a coil spring chamber 93a and an oil chamber 93b. A piston rod 95 is disposed in the coil spring chamber 93a, and a coil spring 96 is disposed around the piston rod 95. The oil chamber 93b communicates with the interior of the free piston portion 92 and is filled with hydraulic oil 97.

[0027] The piston 94 moves rearward due to the restoring force of the coil spring 96, thereby moving the piston rod 95 rearward, and as a result, the main body 91 extends in the front-to-rear direction. At this time, hydraulic oil 97 flows into the oil chamber 93b from the inside of the free piston portion 92, which will be described later. In addition, the piston 94 contracts and moves forward so that a restoring force is generated in the coil spring 96, thereby moving the piston rod 95 forward, and as a result, the main body 91 contracts in the front-to-rear direction. At this time, hydraulic oil 97 flows out from the oil chamber 93b into the inside of the free piston portion 92.

[0028] The rear end of the piston rod 95 is swingably connected to the swing arm 6 via a swing shaft 6a. The front end of the piston rod 95 is fixed to a cylinder 93, and moves back and forth together with the cylinder 93.

[0029] The coil spring 96 is provided in a state where it is locked by, for example, a locking mechanism (not shown) in a state where a biasing force acts in a direction in which the piston 94 and the piston rod 95 move rearward and the main body 91 extends forward and backward. When the locking mechanism is released, the coil spring 96 moves the piston 94 and the piston rod 95 rearward by its restoring force.

[0030] The hydraulic oil 97 fills the oil chamber 93b in the cylinder 93 and the inside of the free piston portion 92. This hydraulic oil 97 flows from the inside of the free piston portion 92 into the oil chamber 93b in the cylinder 93, and also flows from the oil chamber 93b in the cylinder 93 into the inside of the free piston portion 92.

[0031] The free piston portion 92 communicates with an oil chamber 93b in the cylinder 93, allowing hydraulic oil 97 to flow in and out. A piston 92b is slidably disposed inside the free piston portion 92. An opening 92a having an opening is provided above the free piston portion 92, allowing air to flow in and out. As a result, the internal volume of the free piston portion 92 can be adjusted in response to the inflow and outflow of oil by the piston 92b in a free state, and it functions as a relief portion for the hydraulic oil 97.

[0032] The vehicle height adjusting device 9 of this embodiment may employ a configuration in which the locking mechanism of the piston 94 can be operated by a wire (not shown) linked to an operating unit (not shown) provided on a handle (not shown), for example. This allows the driver to adjust the vehicle height by operating the operating unit.

[0033] The rear suspension structure 4 for the motorcycle 1 according to this embodiment having the above-described configuration provides the following effects.

[0034] According to the rear suspension structure 4 for the motorcycle 1 of this embodiment, the free piston portion 92 of the height adjustment device 9 is provided above the main body portion 91. This allows the length of the height adjustment device 9 in the front-to-rear direction to be shorter than conventional height adjustment devices, which in turn allows the length of the motorcycle 1 in the front-to-rear direction to be shorter and the motorcycle 1 to be made more compact. Furthermore, according to the rear suspension structure 4 for the motorcycle 1 of this embodiment, the motorcycle 1 can be made more compact, which improves the handling stability of the motorcycle 1.

[0035] Furthermore, according to the rear suspension structure 4 of the motorcycle 1 of this embodiment, the free piston portion 92 of the vehicle height adjustment device 9 is disposed in a position that overlaps with the link member 8 in a side view. This allows the rear suspension structure 4 to be made more compact, thereby enabling the motorcycle 1 to be made more compact. Furthermore, the rear suspension structure 4 of the motorcycle 1 of this embodiment can contribute to effective use of space, improving the layout flexibility of the motorcycle 1.

[0036] Furthermore, according to the rear suspension structure 4 of the motorcycle 1 according to this embodiment, the link member 8 has a shape that can accommodate the free piston portion 92 therein. This prevents the free piston portion 92 of the vehicle height adjustment device 9 from being exposed to the outside, thereby improving the appearance of the motorcycle 1.

[0037] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention. [Explanation of symbols]

[0038] 1. Motorcycles 2 Body frame 3 rear wheels 4 Rear suspension structure 5 Pivot Frame 5a Pivot (swinging axis) 6 Swingarm 6a Oscillating shaft 7 Rear cushion 8 Link member 81,82 Link plate 8a, 8b, 8c Oscillating shaft 9 Vehicle height adjustment device 91 Main body 92 Free piston part 92a opening 92b piston 93 cylinders 93a Coil spring chamber 93b Oil chamber 94 Piston 95 Piston rod 96 coil spring 97 Hydraulic oil

Claims

1. a swing arm (6) that is swingably connected at its front end to a body frame (2) via a swing shaft (5a), is suspended from the body frame (2) via a rear cushion (7), and supports a rear wheel (3) at its rear end; a link member (8) connected to the body frame (2) and to a lower end of the rear cushion (7); a vehicle height adjustment device (9) provided between the swing arm (6) and the link member (8), The vehicle height adjustment device (9) a main body (91) having a piston (94) and extending and contracting in the front-rear direction to adjust the vehicle height; a free piston portion (92) provided above the main body portion (91) and acting on the main body portion (91) to enable the main body portion (91) to expand and contract, A locking mechanism for the piston (94) can be operated by a wire connected to an operating part provided on the handlebar, thereby enabling the driver to adjust the vehicle height by operating the operating part.

2. 2. The rear suspension structure (4) for a motorcycle (1) according to claim 1, wherein the free piston portion (92) is disposed at a position overlapping the link member (8) in a side view.

3. 3. The rear suspension structure (4) for a motorcycle (1) according to claim 2, wherein the link member (8) has a shape capable of accommodating the free piston portion (92) therein.

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