JP5702071B2 - Motorcycle - Google Patents

Description

  The present invention relates to a motorcycle, and more particularly to a motorcycle having a mass damper for absorbing vibration from a road surface.

  As vibration generated in the motorcycle, there is vibration transmitted from the contact surface between the road surface and the wheel, in addition to vibration caused by the engine.

The former engine vibration is dealt with, for example, by attaching an anti-vibration member to an attachment part of the engine or the like. Alternatively, this is dealt with by providing a rubber damper on the rear arm (Patent Document 1).

  The vibration transmitted from the contact surface between the road surface and the wheel is often generated in a motorcycle for racing, particularly when the corner is high-grid and passes at a large bank angle. As a specific phenomenon, a so-called “chatter phenomenon” occurs in which the front fork vibrates in the axial direction of the steering shaft.

Wherein for suppressing the chatter phenomenon, conventionally, prior to the contact surface between the wheel and the road surface is thought to vibration sources, in the vicinity of the axle mounting bracket description of front fork, mass damper or dynamic consisting of weight (mass) and elastic member A damper is attached (Patent Document 2).

JP-A-6-298149 JP 2007-0290590 A

  However, when installing a damper on the front fork, the space limitation is large, and the degree of freedom of installation is limited, and when a mass damper with a large mass is installed, the entire front fork that is steered to the left and right together with the front wheels is installed. There is a problem that the weight increases and the steering becomes heavy. On the other hand, if mass is restricted with emphasis on steering, it cannot be said that it is effective in reducing vibration.

  It is an object of the present invention to provide a motorcycle that can efficiently suppress vibration transmitted from a road surface to a vehicle body via wheels while preventing an increase in mass of a mass damper, and that prevents steering from becoming heavy. It is aimed.

In order to solve the above-described problems, the present invention includes a front wheel, a rear wheel, and an engine, the engine is supported by a body frame, and a steering shaft is rotatable on a front end head pipe of the body frame. In a motorcycle, a front fork is connected to the steering shaft, the front wheel is rotatably supported at the lower end of the front fork, and a handle is provided at the upper end of the steering shaft. A mass damper that has an elastic member that supports the weight and absorbs vibrations from the road surface, and is attached to a position behind the center of gravity of the vehicle body. The weight is around the center of gravity of the vehicle body as viewed from the side of the vehicle body. It is supported by the elastic member so as to be movable along the direction of rotation.

  The mounting location of the mass damper is preferably inward of the vehicle width rather than both ends of the motorcycle in the vehicle width direction, and the rear frame located behind the seat and above the rear wheel, or below the seat on which the rider sits Alternatively, a swing arm that supports the rear wheel can be applied. When attached to the swing arm, the rear end of the swing arm is suitable.

  In the present invention, preferably, the natural frequency of the mass damper is set to 15 hertz or more and 25 hertz or less, and the weight of the mass damper is rotated around the center of gravity of the vehicle body as viewed from the side of the vehicle body. Is elastically supported so as to be movable substantially along.

  As the weight of the mass damper, a functional component having a function other than the mass damper, for example, a battery, a tool, a fuel tank, an ABS hydraulic unit, or the like can be used.

(1) In a motorcycle in which the front wheels are supported by a front fork, the mass damper is arranged behind the center of gravity of the vehicle, and the weight can be moved substantially along the direction of rotation around the center of gravity of the vehicle body. Since it is supported by an elastic member, it suppresses vibration in the axial direction (substantially up and down direction) of the front fork and eliminates an increase in the weight of the steering shaft part, thereby preventing an increase in the force required for the operation and reducing the travel fee. The ring can be prevented from lowering. In addition, since it is arranged on the side close to the contact surface between the road surface and the rear wheel that is likely to be a vibration source, vibration transmitted from the road surface via the rear wheel is prevented while preventing the mass damper from becoming large in mass. Absorption can be efficiently performed, and the degree of freedom of arrangement of the mass damper can be increased while preventing adverse effects on the steering performance.

(2) When the mass damper is disposed inward from both ends of the motorcycle in the vehicle width direction, it is possible to prevent the obstacle outside the vehicle body from contacting the mass damper.

(3) When a mass damper is disposed behind the center of gravity of the vehicle and below the seat, the upper portion of the mass damper is covered with the seat, and the left and right sides are covered with the side cover or cowling of the vehicle body. As a result, the appearance can be improved and the mass damper can be protected from scattered stones, gravel or muddy water. Moreover, since the weight is located near the center of gravity of the vehicle, the ride comfort during straight running is improved.

(4) Even when it is arranged on the rear frame located above the rear wheel, the mass damper can be easily covered from the outside by the rear cowling of the vehicle body, the appearance can be improved, and the scattered stones Can protect the mass damper from gravel or muddy water.

(5) When the mass damper is supported by the swing arm that is behind the center of gravity of the vehicle and directly supports the rear wheels, the effect of absorbing vibration transmitted from the road surface is increased. In particular, if it is attached to the rear end of the swing arm, the vibration absorbing effect is further improved. In addition, when mounted on a swing arm, the vehicle can have a low center of gravity.

(6) The natural frequency of the mass damper is set to 15 Hz or more and 25 Hz or less, and the weight of the mass damper is moved substantially along the direction of rotation around the center of gravity of the vehicle body when viewed from the side of the vehicle body. When elastically supported, vibration (15 Hz to 25 Hz) that is transmitted from the rear wheel and rotates the vehicle body around the center of gravity can be suitably suppressed.

(7) As the weight of the mass damper, a functional component that functions other than the mass damper, such as a battery, a tool, a fuel tank, or an ABS hydraulic unit, is disposed inside the left and right walls of the vehicle body. Then, it is not necessary to separately provide a mass damper dedicated mass, and the number of parts can be reduced.

1 is a left side view of a motorcycle according to a first embodiment of the present invention. Fig. 2 is a perspective view of a swing arm and a rear wheel of the motorcycle shown in Fig. 1. FIG. 2 is an enlarged longitudinal sectional view of a mass damper attached to the motorcycle of FIG. 1. It is a graph which shows the resonance range of the mass damper of FIG. FIG. 6 is a perspective view of a body frame of a motorcycle according to a second embodiment of the present invention. It is an enlarged view of the principal part of FIG. FIG. 6 is a perspective view of a body frame of a motorcycle according to a third embodiment of the present invention. It is an enlarged view of the principal part of FIG. It is a longitudinal cross-sectional enlarged view which shows the modification of a mass damper.

[First Embodiment]
1 to 4 show a motorcycle provided with a mass damper according to a first embodiment of the present invention, and the first embodiment will be described based on these drawings.

  In FIG. 1 showing a left side view of the entire motorcycle, a vehicle body frame 1 includes a main frame 3 that extends rearward from a head pipe 2 at the front end and a rear end portion that curves downward, and a rear lower end portion of the main frame 3. The formed swing arm bracket part 4 and a rear frame 5 extending rearward from the swing arm bracket part 4 above the rear wheel 24 are provided.

  A steering shaft 8 is supported on the head pipe 2 so as to be rotatable in the left-right direction, and a pair of left and right front forks 10 extending downward are connected to the steering shaft 8 via a pair of upper and lower brackets (not shown). The front wheel 11 is rotatably supported at the lower end of the front fork 10. A handle 12 is provided at the upper end of the steering shaft 8.

  An engine 20 is disposed below the main frame 3, and the engine 20 is supported by the main frame 3 and the swing arm bracket 4 via a prevention member or the like. On the upper side of the body frame 1, a fuel tank 14 and a seat 15 on which a rider sits are provided in order from the front. Side covers 9 are arranged on the left and right sides below the seat 15.

  A pair of left and right swing arms 22 is supported on the swing arm bracket portion 4 via a pivot shaft 21 so as to be rotatable in the vertical direction, and the swing arm 22 extends substantially rearward. The rear wheel 24 is rotatably supported by a rear end portion of the swing arm 22 via a rear axle 23.

  This motorcycle is for racing, and a front cowling 18 that covers the front of the handle 12, the head pipe 2, the engine 20, and the like is provided in addition to the front fender 16 that covers the front wheel 11 at the front of the vehicle body. ing. In addition to the rear fender 25 that covers the upper portion of the rear wheel 24, a rear cowling 26 that covers the rear half of the rear frame 5 is provided at the rear of the vehicle body.

  In the present embodiment, the position of the center of gravity G1 when the motorcycle is viewed from the side is the front and upper position of the pivot shaft 21 of the swing arm 22 and is connected to the rear intake of the cylinder head 20a of the engine 20. The position corresponding to or near the throttle body 27 is set.

  FIG. 2 is an enlarged perspective view of the swing arm 22 and the rear wheel 24. The mass damper 30 is attached to an L-shaped stand holder 31 provided at the rear end of the left and right swing arms 22 by upper and lower bolts 32, respectively. It is attached so as to be substantially along the vertical direction. The stand holder 31 is a member placed on a U-shaped stand for lifting and holding the rear portion of the vehicle body when the vehicle is stopped or repaired.

  As described above, the mass damper 30 is detachably attached to a holder portion such as the stand holder 31 provided in advance on the swing arm 22. Accordingly, it is not necessary to newly form a structure for attaching the mass damper 30 to the swing arm 22, and versatility can be improved. In addition, since the mass damper 30 is configured to be detachable, the mass damper 30 can be removed during traveling where there is little possibility of chatter vibrations, such as other than racing, and convenience can be improved.

  The mass damper 30 is disposed at the rear end of the swing arm 22 and in the vicinity of the rear wheel axle. Thereby, it is easy to suppress the vibration before it is transmitted from the rear wheel 24 to the vehicle body frame 1, and the vibration suppressing effect can be enhanced. By suppressing the vibration at a position close to the vibration source in this way, it is possible to prevent the mass of the mass damper 30 from increasing in size compared to the case where the mass damper is arranged at another position, and to have a high vibration suppressing effect. Can be obtained.

  Further, the direction in which the weight of the mass damper 30 vibrates is set to a direction along the circumferential direction around the pivot shaft 21 of the swing arm 22, as will be described later, at the rear end portion of the swing arm 22. In the present embodiment, the weight vibration direction is set so as to be orthogonal to the direction in which the swing arm extends, in other words, the vertical direction. Moreover, you may incline not only to a perpendicular direction but to the direction which advances ahead as it progresses upwards. Moreover, in this embodiment, since the left and right mass dampers are respectively positioned, it is possible to prevent the left and right weight balance due to the provision of the mass damper from becoming uneven.

  3 is an enlarged vertical cross-sectional view of the mass damper 30. The mass damper 30 has a rectangular tube case body 41 that is long in a substantially vertical direction, and an upper lid 42 and a lower lid 43 that close the upper and lower ends of the case body 41. A weight 44 housed in the case body 41 so as to be movable in the vertical direction (case body length direction), and an upper coil spring 45 and a lower coil disposed on the upper side and the lower side of the weight 44, respectively. And a spring 46.

  The upper and lower lids 42 and 43 are integrally coupled to the case main body 41 by a bolt 47 that penetrates the case main body 41 in the length direction of the case main body and a nut 48 screwed to the lower end portion of the bolt 47. .

  The bolt 47 passes on the center line O1 of the cross section of the case body 41, and a through hole 44a through which the bolt 47 passes is formed in the shaft center portion of the weight 44. A plurality of bearing metals 49 are fitted on the inner peripheral surface of the through-hole 44a, and the weight 44 moves in the vertical direction to the outer peripheral surface of the bolt 47 (the surface on which the male thread portion is not formed) via the bearing metal 49. Fits freely.

  The upper coil spring 45 and the lower coil spring 46 have substantially the same spring constant, and the upper coil spring 42 is contracted between the upper end surface of the weight 44 and the upper lid 42 so that the lower coil The spring 46 is contracted between the lower end surface of the weight 44 and the lower lid 43. The set loads of the upper and lower coil springs 45, 46 are set to be substantially the same, or the lower coil spring 46 is weakly crowned. Due to the balance between the elastic forces of the upper and lower coil springs 45, 46, the weight 44 is held at a substantially central position in the length direction of the case body 41.

  Regarding the characteristics of the damping force due to the weight of the weight 44 and the spring constants of the coil springs 42 and 43, the vehicle vibrates due to the vibration generated on the contact surface between the road surface E and the rear wheel 24 and transmitted to the rear wheel 24. It is set so that it can resonate in the vicinity of the vibration frequency to actively attenuate the vibration. The frequency at which a motorcycle vibrates is generally in the range of 19 to 21 hertz (Hz), and is usually about 20 hertz. Of course, considering various types of motorcycles, the range is at most 15 to 25 hertz.

When the mass of the weight 44 is M and the spring constant is K, the mass damper 30 is selected so as to satisfy the following equation, for example. For example, the lower limit frequency is set to 15 to 19 hertz and the upper limit frequency is set to 21 to 25 hertz.
Lower limit frequency ≤ (1 / 2π) (√K / √M) ≤ upper limit frequency

  In this embodiment, the natural frequency of the motorcycle is set to 20 hertz, for example, and as shown by the solid line graph X1 in FIG. Is set to

  The case body 41 and the upper and lower lids 42 and 43 of the mass damper 30 are made of aluminum, but may be made of iron or resin. Further, the material of the weight 44 is preferably as compact as possible and a material capable of obtaining a large mass, and therefore, tungsten having a large specific gravity is used. Of course, iron or other metals can be used to reduce the cost. Incidentally, the mass of the weight 44 of the mass damper 30 according to the first embodiment is 300 g per mass damper 30. Accordingly, since the two mass dampers 30 are arranged on the left and right, the weight 44 of a total of 600 g is used for one vehicle. Further, the weight 44 is configured to be movable in the range of about 15 mm to 20 mm in the vertical direction from the center position in the vertical direction.

  It is also possible to inject a viscous fluid such as water or non-flammable oil into the case body 41. When the viscous fluid is injected, the viscous fluid gradually changes depending on the viscosity. By applying the damping force, it is possible to expand the resonance range in which the mass damper 30 can absorb vibration, as indicated by the broken line graph X2 in FIG. In this manner, a damping force may be generated in the elastic body itself or the moving space of the weight 44.

(Function)
At the time of straight running, vibrations substantially corresponding to the natural frequency of the vehicle are hardly generated as vibrations with the contact surface between the road surface E and the rear wheel 24 as a vibration source. Therefore, even if the mass damper 30 is not provided, Chatter phenomenon does not occur in the front fork 10 and its vicinity.

  When turning a corner, vibration occurs with the contact surface between the road surface E and the rear wheel 24 as a vibration source in a high grip state with respect to the road surface E and at a large bank angle. Is transmitted to the vehicle body via the rear wheel 24. In response to such vibration, the mass damper 30 resonates at a frequency in the vicinity of the frequency, so that the vibration is attenuated, thereby preventing the chatter phenomenon in which the entire vehicle body, particularly the front fork 10 vibrates as indicated by the arrow B2. it can.

  In recent research on motorcycles, there is a report that the vibration transmitted from the road surface to the vehicle body has a greater effect transmitted from the rear wheels than the front wheels. In the present invention, since the mass damper is provided behind the center of gravity, a large amount of vibration transmitted from the rear wheels can be absorbed, and the chatter phenomenon that occurs during running of a race can be effectively suppressed.

  Further, since the mass dampers 30 are arranged in a pair of left and right, it is possible to balance the left and right balance of the vehicle and to absorb the left and right shakes.

  When the mass damper 30 is attached to the swing arm located below the center of gravity, the vehicle can be lowered in center of gravity. Moreover, a mass damper can be arrange | positioned in a location with few space restrictions.

[Second Embodiment]
5 and 6 show a second embodiment, which has a structure in which a pair of left and right mass dampers 30 are arranged below the seat 15. In FIG. 5 showing the entire body frame, a pair of left and right mass dampers 30 disposed below the seat 15 are supported on the upper surface of the front half of the rear frame 5 via a plurality of support legs 60 and a holding bracket plate 61. Has been.

  In FIG. 6, which is an enlarged perspective view of the front half of the rear frame 5, the support leg 60 is joined to the front half of the rear frame 5 by welding. The holding bracket plate 61 integrally includes an upper wall 61a and a pair of side walls 61b extending downward from the left and right end edges of the upper wall 61a, and both front and rear ends of the upper wall 61a are supported by support legs 60, A pair of left and right mass dampers 30 are attached to both side walls 61b by bolts or the like.

  The internal structure of the left and right mass dampers 30 is the same as the structure shown in FIG. 3 and is arranged at equal left and right positions with respect to the vehicle width center line.

  Both mass dampers 30 are covered with a sheet 15 at the top, and side covers 9 (see FIG. 1) and the like on the left and right sides.

  The operation of the mass damper 30 of FIGS. 5 and 6 is the same as that of the first embodiment, but the mass damper 30 of the second embodiment has at least the upper and left and right sides of the seat 15. And since it is covered with the side cover 9, stones, gravel, muddy water, etc. scattered from the outside do not collide and are protected.

  Compared to the first embodiment, the mass damper 30 is not configured to protrude in the vehicle width direction from the vehicle body, and an increase in the vehicle width direction dimension of the entire vehicle body can be prevented. In addition, the mass damper 30 is disposed on the holding bracket plate 61 that supports the seat 15, thereby preventing chatter vibration from being transmitted to the seat 15. Further, the swing arm 22 and the main frame 3 are connected via a rear suspension, and vibrations are suppressed at a seat frame position formed at a position away from the rear suspension connecting portion formed on the main frame 3. Therefore, the mass damper 30 is disposed at a position away from the vibration center, and the weight 44 can be prevented from being enlarged and the vibration suppressing effect can be enhanced.

  Note that the general arrangement position of the mass damper 30 of the present embodiment with respect to the entire vehicle is indicated by reference numeral 30 (A1) in FIG.

[Third Embodiment]
7 and 8 show a third embodiment, which has a structure in which a pair of left and right mass dampers 30 are arranged at the rear end portion of the rear frame 5. In FIG. 7 showing the entire body frame, a pair of left and right mass dampers 30 arranged at the rear end of the rear frame 5 are supported by the rear frame 5 via a support frame 71.

  In FIG. 8, which is an enlarged perspective view of the rear half of the rear frame 5, the support frame 71 is attached to the rear end of the rear frame 5 so as to be adjustable in the left-right direction using bolts (not shown) and a long hole. The left and right mass dampers 30, 30 are attached to the left and right side walls 71a of the support frame 71 with bolts or the like.

  The internal structure of the left and right mass dampers 30 is the same as the structure shown in FIG. 3 and is arranged at equal left and right positions with respect to the vehicle width center line.

  Both mass dampers 30 are covered with the rear cowling 26 (see FIG. 1) and the like on the upper side and the left and right sides.

  The operation of the mass damper 30 shown in FIGS. 7 and 8 is the same as that of the first embodiment, but the mass damper 30 of the embodiment has the same effect as that of the second embodiment. . That is, since the upper side and the left and right sides are covered with the rear cowling 26, stones, gravel, muddy water, etc. scattered from the outside do not collide and are protected.

  Further, since the mass damper 30 is built in the vehicle body, an increase in the vehicle width direction can be prevented. Further, since vibration is suppressed at the rear end position of the seat frame formed at a position away from the rear suspension connection portion formed on the main frame 3, a mass damper is disposed at a position away from the vibration center. It is possible to prevent the weight from becoming large and enhance the vibration suppressing effect.

  Note that the general arrangement position of the mass damper 30 of the present embodiment with respect to the entire vehicle is indicated by reference numeral 30 (A2) in FIG.

[Other embodiments]
(1) FIG. 9 is a modification of the mass damper 30. The difference from the structure of FIG. 3 is that the weight 44 housed in one case body 41 is replaced with an upper weight portion 44a and a lower weight portion 44b. That is, the upper and lower portions are divided into two, and the concave portions 74 are formed at the positions where the weight portions 44a and 44b are aligned. The recess 74 can be used in a hollow state, but the mass of the entire weight 44 can be easily adjusted by fitting a cylindrical adjustment weight 73 of an appropriate size. Other structures are the same as those in FIG. 3, and the same components are denoted by the same reference numerals. Thereby, the resonance frequency can be finely adjusted according to the vehicle body, and the vibration suppression effect can be further enhanced.

(2) In addition to the swing arm 22 and the rear frame 5, the mass damper 30 can be attached to the swing arm bracket 4 or the like as long as it is behind the center of gravity G1 of the vehicle.

(3) As an elastic member of the mass damper 30, it is also possible to use a leaf spring or rubber in addition to the coil spring.

(4) A single mass damper 30 may be arranged on the center of the vehicle width.

(5) The structure is not limited to the structure in which the mass damper is arranged at one place, and can be arranged at two or more places behind the center of gravity of the vehicle, such as a swing arm and a rear frame.

(6) The battery mounted on the vehicle can be used as a mass damper weight, and other functional parts such as a fuel tank, an ABS hydraulic unit, an engine, an ECU, a battery, a reservoir tank, or a tool, It can also be used as a mass damper weight.

(7) The present invention is not limited to a racing motorcycle, and can of course be applied to a motorcycle traveling on a general road.

(8) Various modifications and changes can be made without departing from the spirit and scope of the present invention described in the claims.

(9) Since the present invention absorbs vibrations from the road surface, the same effect can be obtained even in a motorcycle using an electric motor as a drive source in addition to an internal combustion engine (engine) as a drive source. It is not limited to the drive source mounted. Similarly, the frame structure is not limited to this embodiment, and the present invention can be applied to any frame structure. Further, the position of the center of gravity of the vehicle of the present invention is an example, and even if the center of gravity position is arranged at an arbitrary position as long as the mass damper is arranged behind the position of the center of gravity, the effect of the present invention is achieved. Can be fully demonstrated. For example, when the rear suspension connection portion of the main frame is biased to one side in the vehicle width direction, a mass damper may be arranged on the front-rear direction extension surface of the rear suspension connection portion arrangement position. Also, the configuration of the mass damper may be any configuration as long as the weight resonates at the frequency at which chatter vibration occurs, and the specific structure can be changed as appropriate. For example, a weight support structure, a weight shape, a case shape, a case support structure, and the like can be appropriately selected according to the vehicle body.

DESCRIPTION OF SYMBOLS 1 Body frame 2 Head pipe 3 Main frame 4 Swing arm bracket part 5 Rear frame 9 Side cover 22 Swing arm 18 Front cowling 26 Rear cowling 30 Mass damper 41 Body cover 42, 43 Lid 44 Weight 45, 46 Coil spring

Claims (8)

The vehicle has a front wheel, a rear wheel, and an engine. The engine is supported by a body frame, a steering shaft is rotatably supported by a front end head pipe of the body frame, and a front fork is connected to the steering shaft. In the motorcycle, the front wheel is rotatably supported at the lower end of the front fork, and the handle is provided at the upper end of the steering shaft.
A mass damper that has a weight and an elastic member that supports the weight, and that absorbs vibrations from the road surface, is attached to a position behind the center of gravity of the vehicle body,
The motorcycle according to claim 1, wherein the weight is supported by the elastic member so as to be movable along a direction of rotation around the center of gravity of the vehicle body as viewed from the side of the vehicle body . The motorcycle according to claim 1,
The mass damper includes a case main body that movably houses the weight,
A motorcycle in which the case body is detachably attached to the vehicle body . The motorcycle according to claim 1 or 2,
The mass damper is a motorcycle disposed at a position rearward of the seat . The motorcycle according to claim 1,
The rear wheel is supported by a rear end portion of a swing arm that is swingably supported by the body frame in the vertical direction;
The mass damper is a motorcycle supported by the swing arm . The motorcycle according to claim 4 ,
The mass damper is a motorcycle arranged at a position near the rear axle . The motorcycle according to claim 1 ,
The mass damper is a motorcycle arranged at a position where an upper portion is covered with a seat . The motorcycle according to claim 6 ,
The mass damper is a motorcycle arranged on a holding bracket plate that supports the seat . The motorcycle according to any one of claims 1 to 7,
A motorcycle provided with functional parts that serve as the weight of the mass damper and are arranged inwardly of the left and right walls of the vehicle body to perform functions other than the mass damper.

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