JP2009179163A - Rear swing arm for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear swing arm for a motorcycle which prevents mad and water from being deposited on a front coupling member besides securing high strength and rigidity. <P>SOLUTION: A rear swing arm 17 includes a pair of right and left arm parts 40, 41 and a front coupling member 42 for coupling the arm parts 40, 41. A recess with a L-shape in a side view opened in the front and top of a vehicle is formed by being surrounded by arm front halves 45, 51 constituting the arm members 40, 41 and by a central coupling member 56 and upper half coupling member 57 constituting the front coupling member 42. The central coupling member 56 is provided with an upper surface part 59 tilting toward a front lower half from a rear upper half of a vehicle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rear swing arm of a motorcycle.

  One type of motorcycle is called “American”. This "American" type motorcycle is basically equipped with a V-type 2-cylinder engine regardless of the displacement. In addition, large motorcycles, including those of the “American” type, often employ a “double cradle” type frame due to the required high rigidity of the frame. Furthermore, in the “American” type motorcycles, those that do not have a rear-wheel suspension device called a “hard tail” in which a rear wheel shaft support portion is formed integrally with a frame tend to be preferred. However, if the rear wheels are pivotally supported by a “hard tail” type frame, the riding comfort of the motorcycle and the grounding property of the rear wheels cannot be obtained sufficiently.

  Therefore, Patent Document 1 discloses an “American” type motorcycle in which a rear swing arm is formed to resemble a shaft support portion of a “hard tail” type rear wheel and a rear wheel suspension device is mounted.

  Here, the rear swing arm generally has a front end pivotally attached to the body frame via, for example, a swing pivot shaft, and pivotally supports a rear wheel at a rear end that is a free end.

  Further, the rear swing arm is composed of a pair of left and right arm portions and a front connecting member provided between the front portions of the arm portions. A pivot shaft support is provided at the front end of the arm. The rear swing arm is pivotally attached to the vehicle body frame via a pivot shaft by a pivot shaft support portion. A rear wheel bearing portion is provided at the rear end portion of the arm portion, and the rear wheel is rotatably supported by the rear wheel bearing portion.

The front connecting member of the rear swing arm is provided with a bracket to which one end of the rear wheel suspension device is attached. The other end of the rear wheel suspension is attached to the body frame.
JP 2005-67504 A

  The rear swing arm described in Patent Document 1 includes a pair of left and right main members bent forward at the center, a pair of left and right upper members extending obliquely downward from the upper end of the main member, A pair of left and right lower members that extend obliquely upward from the lower end, and a pair of left and right connecting members that connect the upper member and the lower member at their rear ends. The left and right main members have a cylindrical cross member in the vehicle body width direction in the center part through which the swing pivot shaft is inserted, the upper end part, and the lower end part, respectively, and the entire rear swing arm is configured in a ramen structure. Rigidity is ensured.

  As another example of the rear swing arm, there is a rear swing arm in which a cross member constructed on a pair of left and right arm portions is formed in a plate shape in order to further improve the rigidity of the rear swing arm.

  FIG. 6 is a perspective view showing an example of a conventional rear swing arm used in a motorcycle.

  As shown in FIG. 6, a conventional rear swing arm 70 is used for a motorcycle in which a shaft drive system is used for a secondary speed reduction mechanism. The conventional rear swing arm 70 includes a pair of left and right arm portions 40 and 41 and a front connection member 42 that connects the arm portions 40 and 41.

  The arm member 40 includes an arm front half 45 formed in a substantially triangular shape in a side view that extends vertically from a front end portion toward a rear end portion having a pivot shaft support portion 44 through which a swing pivot shaft (not shown) passes, and an arm An upper member 46 that extends obliquely downward from the upper end of the front half 45, a lower member 47 that extends obliquely upward from the lower end of the arm front half 45, and a substantially vertical center of the arm front half 45 It is comprised from the shaft case 48 extended in the front-back in the part.

  The arm member 41 includes an arm front half 51 formed in a substantially triangular shape in a side view that extends vertically from the front end portion having the pivot shaft support portion 50 toward the rear end portion, and obliquely downward from the upper end of the arm front half portion 51. An extended upper member 52, a lower member 53 extending obliquely upward from the lower end of the arm front half 51, and a rear wheel bearing member 54 for connecting the upper member 52 and the lower member 53 at the rear end Consists of

  That is, the pivot shaft support portions 44 and 50, the arm front half portions 45 and 51, the upper members 46 and 52, and the lower members 47 and 53 are each configured as a pair on the left and right.

  The front connecting member 42 includes a hollow plate-like center connecting member 56 that is installed at a substantially vertical center of the pair of left and right arm front halves 45 and 51, and a rear end of the pair of left and right arm front halves 45 and 51. A hollow plate-like upper half connecting member 57 installed on the upper half, and a hollow plate-like lower half connecting member 58 installed on the lower half of the rear ends of the pair of left and right arm front halves 45, 51; Consists of

  In the motorcycle using the conventional rear swing arm 70 configured as described above, it is desirable to dispose the front end portion of the rear fender behind the motorcycle rather than the upper end portion of the upper half connecting member 57 of the rear swing arm 70. . However, when the front end of the rear fender is arranged in front of the motorcycle with respect to the upper end of the upper half connecting member 57 due to shortening of the wheel base, etc., the mud splashed up to the rear fender by the rotation of the rear wheel And a muddy water are surrounded by a pair of left and right arm front halves 45, 51, a central connecting member 56, and an upper half connecting member 57 from the front end of the rear fender, and are opened to the front and top of the motorcycle. It dripped into the L-shaped concave portion and deposited on the upper surface portion of the central connecting member 56 (hatched area A in FIG. 6). The mud and water accumulated in the recess increase the unsprung weight of the motorcycle and cause a decrease in motion performance. Further, if mud or water accumulates in the recesses for a long period of time, it causes inconvenience in appearance and a reduction in strength of the rear swing arm due to rusting.

  An object of the present invention is to provide a rear swing arm of a motorcycle in which mud and water are not deposited on a front connecting member while ensuring high strength and rigidity.

  In order to solve the above-described problems, in the rear swing arm of the motorcycle according to the present invention, a seat seat placed on the body frame and an article storage portion provided below the seat seat and provided on the body frame. A swing arm of a motorcycle having an arm front half portion formed in a substantially triangular shape in a side view extending in a vertical direction from a front end portion to a rear end portion having a pivot shaft support portion through which a swing pivot shaft passes, and the arm front half portion Left and right having an upper member that extends obliquely downward from the upper end of the arm and a lower member that extends obliquely upward from the lower end of the front half of the arm and pivotally supports the rear wheel at the rear end A pair of arm portions, a central connection member that is erected in a substantially vertical central portion of the front half of the arm, and an upper half connection member that is erected in the upper half of the rear end of the front half of the arm An L-shaped recess that is opened forward and upward by the central connection member and the upper half connection member is formed in the vehicle width direction central portion of the front connection member. The article storage portion can be projected and retracted, and the center connecting member has an upper surface portion that is inclined from the rear upper side toward the front lower side.

  According to the present invention, it is possible to provide a rear swing arm of a motorcycle in which mud and water are not deposited on the front connecting member while ensuring high strength and rigidity.

  An embodiment of a rear swing arm of a motorcycle according to the present invention will be described with reference to FIGS.

  FIG. 1 is a left side view showing a motorcycle using an example of an embodiment of a rear swing arm according to the present invention.

  As shown in FIG. 1, a motorcycle 1 includes a body frame 2 that is mainly formed of a steel pipe and is formed in a double cradle type. A front and rear two-cylinder V-type engine 3 is mounted on the front half (double cradle portion) of the body frame 2, and a fuel tank 4 is placed above the body frame 2 so as to be positioned above the V-type engine 3. The A seat 5 and a rear fender 6 are sequentially arranged behind the fuel tank 4, and a passenger seat 7 is provided on the rear fender 6. A pair of left and right steps 8 are provided near the front lower part of the body frame 2, and a radiator 9 is installed on the front surface of the body frame 2.

  A front fork 11 that supports the front wheel 10 is pivotally supported on the front head of the vehicle body frame 2 together with a handle bar 12, a front fender 14, and the like so as to be rotatable left and right. On the other hand, a swing pivot shaft 15 is installed in the center lower portion of the body frame 2 in the vehicle width direction. A rear swing arm 17 that supports the rear wheel 16 is pivotally supported by the swing pivot shaft 15 in the rear half of the body frame 2 so as to be rotatable up and down. A rear wheel suspension device (not shown) is provided near the base of the rear swing arm 17. A shaft drive system is used for the secondary reduction mechanism of the motorcycle 1, and the output of the V-type engine 3 is transmitted to the rear wheel via a transmission 19, for example, by a drive shaft (not shown) inserted into the rear swing arm 17. 16 is transmitted.

  The motorcycle 1 is an American type vehicle in which the position of the handle bar 12 is high and the position of the seating seat 5 is low.

  FIG. 2 is a partial longitudinal sectional view of a motorcycle in which an example of an embodiment of a rear swing arm according to the present invention is used.

  As shown in FIG. 2, the body frame 2 of the motorcycle 1 includes a head pipe 22 provided at the front head and a pair of left and right main frames 23 extending obliquely downward from the upper half of the head pipe 22. And a pair of left and right down tubes 24 that extend substantially downward from the lower half of the head pipe 22 and are curved and extended backward.

  A pair of left and right front bridge members 35 are installed between the front part of each of the left and right main frames 23 and the front part of the down tube 24.

  An upper bridge member 27 is installed in the vehicle width direction at the rear portions of the left and right main frames 23, and a lower bridge member 28 is installed at the rear portions of the left and right down tubes 24. Between the upper bridge member 27 and the lower bridge member 28, a pair of left and right pivot bracket portions 30 spaced in the vehicle width direction are installed. The pivot bracket portion 30 is provided with a pivot shaft support portion 31 on which the swing pivot shaft 15 is supported while being displaced downwardly of the vehicle.

  A pair of left and right rear fender brackets 32 to which the rear fender 6 is attached are provided at the rear end of each main frame 23. At the front end of the rear fender 6, a mudguard member 33 that prevents mud and water splashed by the rear wheel 16 from splashing in front of the vehicle body frame 2 is extended toward the lower side of the vehicle.

  Below the seating seat 5 detachably provided from the rear part of the left and right main frames 23 to the front part of the rear fender 6, the left and right main frames 23, the upper bridge member 27, and the rear fender 6 are surrounded. Thus, an article storage portion 35 that opens upward is formed. The article storage unit 35 is disposed approximately at the center of the motorcycle 1 in the vehicle width direction.

  The article storage section 35 has a box-shaped article storage section wall 36 composed of a front wall 36a, a bottom wall 36b, a rear wall 36c, and left and right side walls (not shown). Be contained. Since the mudguard member 33 is provided closer to the front end portion of the rear fender 6 than the article accommodating portion wall 36, mud and water splashed by the rear wheel 16 travels along the rear fender 6 and enters the article accommodating portion 35. Don't get in.

  FIG. 3 is a perspective view showing an example of an embodiment of a rear swing arm according to the present invention.

  As shown in FIGS. 2 and 3, the rear swing arm 17 includes a pair of left and right arm portions 40, 41 and a front connection member 42 that connects the arm portions 40, 41.

  The arm member 40 includes a hollow arm front half 45 formed in a substantially triangular shape in a side view extending in a vertical direction from a front end portion having a pivot shaft support portion 44 through which the swing pivot shaft 15 is penetrated toward a rear end portion, and an arm front half. An upper member 46 extending obliquely downward from the upper end of the portion 45, a lower member 47 extending obliquely upward from the lower end of the arm front half 45, and a substantially central portion in the vertical direction of the arm front half 45 , And a shaft rear support portion (not shown) provided at the rear ends of the upper member 46, the lower member 47, and the shaft case 48.

  The arm member 41 includes a hollow arm front half 51 formed in a substantially triangular shape in a side view extending in a vertical direction from a front end portion having a pivot shaft support portion 50 through which the swing pivot shaft 15 is penetrated toward a rear end portion, and an arm front half. An upper member 52 extending obliquely downward from the upper end of the portion 51, a lower member 53 extending obliquely upward from the lower end of the arm front half 51, and the upper member 52 and the lower member 53 The rear wheel bearing member 54 is connected at the end.

  The pivot shaft support portions 44 and 50, the arm front half portions 45 and 51, the upper members 46 and 52, and the lower members 47 and 53 are each configured as a pair on the left and right.

  A shaft rear support portion provided at the rear end of the arm member 40 supports the axle (not shown) of the rear wheel 16 together with the rear wheel bearing member 54 and a joint member (not shown) at the rear end of the drive shaft (not shown). A drive-side bevel gear (not shown) coupled via a drive-side bevel gear (not shown) and a driven-side bevel gear (not shown) that are engaged with the drive-side bevel gear and transmit engine output to the rear wheel 16 are supported. The drive shaft is inserted into the shaft case 48, and the front end of the drive shaft is coupled to the transmission 19 via a universal joint (not shown).

  The front connecting member 42 includes a hollow plate-like center connecting member 56 that is installed at a substantially vertical center of the pair of left and right arm front halves 45 and 51, and a rear end of the pair of left and right arm front halves 45 and 51. A hollow plate-like upper half connecting member 57 installed on the upper half, and a hollow plate-like lower half connecting member 58 installed on the lower half of the rear ends of the pair of left and right arm front halves 45, 51; Consists of

  The center portion connecting member 56 has an upper surface portion 59 that is inclined from the rear upper side to the front lower side of the motorcycle 1, and the rear swing arm 17 rotates up and down, that is, even if the rear portion of the motorcycle 1 moves up and down. The upper surface portion 59 is always formed so as to be inclined from the rear upper side to the front lower side of the motorcycle 1.

  An article storage portion 35 provided in the vehicle body frame 2 is disposed above the upper surface portion 59 of the central connection member 56 of the rear swing arm 17. The article storage unit 35 is surrounded by the arm front halves 45 and 51, the center connection member 56, and the upper half connection member 57, and appears and disappears in an L-shaped recess opened in front and above the motorcycle 1. It is possible to arrange. The article storage portion 35, the arm front half portions 45 and 51, the center portion connecting member 56, and the upper half portion connecting member 57 are separated from each other and do not interfere with each other by the rotation of the swing arm 17.

  4 and 5 are perspective views showing another example of the embodiment of the rear swing arm according to the present invention.

  The upper surface portion 59 of the rear swing arm 17 can be configured not only with a surface that is uniformly inclined from the rear upper side to the front lower side of the motorcycle 1 but also with a surface that is partially changed in inclination angle. is there. For example, as shown in FIG. 4, the upper surface portion 59A of the rear swing arm 17 is inclined from the upper center in the vehicle width direction toward the lower outer side in the vehicle width direction, and the rear end of the motorcycle 1 at the outer end in the vehicle width direction. It has a concave groove 60 formed by a surface inclined from the upper side toward the front lower side.

  Further, as shown in FIG. 5, the upper surface portion 59B of the rear swing arm 17 is inclined from the upper side in the vehicle width direction toward the lower center in the vehicle width direction. It has a ditch | groove 60A formed in the surface which inclines toward the front lower direction from back upper direction.

  The secondary reduction mechanism of the motorcycle 1 is not limited to the shaft drive system, and may be a chain drive system or a drive belt system.

  According to the rear swing arm 17 according to the present embodiment, it is possible to shift the swing pivot shaft 15 toward the front side of the motorcycle 1 while securing an installation space for the article storage portion 35 provided in the vehicle body frame 2. The wheel base of the motorcycle 1 can be shortened to reduce the overall length of the vehicle.

  In addition, according to the rear swing arm 17, an L-shaped recess in which the article storage portion 35 can protrude and retract can be formed in the vehicle width direction center portion of the front connecting member 42, so that the height of the seating seat 5 can be increased. A large-capacity article storage unit 35 can be formed without increasing the height.

  Further, the rear swing arm 17 has a very high bending rigidity due to the arm portions 40 and 41 having a substantially rhombic shape in a side view made up of arm front halves 45 and 51 having a substantially triangular shape in a side view, upper members 46 and 52, and lower members 47 and 53. And a pair of left and right arm portions 40, 41 having a substantially rhombic shape when viewed from the side, are laid by the upper half connecting member 57 and the lower half connecting member 58, thereby providing very high torsional rigidity. Therefore, the steering stability of the motorcycle 1 using the rear swing arm 17 is improved.

  Furthermore, in the motorcycle 1, mud and water splashed by the rear wheel 16 and dripping from the front end of the rear fender 6 do not scatter to the front of the vehicle body frame 2 and are collected in a concentrated manner on the rear swing arm 17. The Rukoto. Then, the mud and water collected by the rear swing arm 17 will drip onto the upper surface portion 59 of the central connection member 56 (solid arrow A in FIG. 2), and the position is always maintained by the inclined surface provided on the upper surface portion 59. It flows out to the front side of the vehicle where energy is low and is excreted to the bottom side of the vehicle. On the other hand, when the motorcycle 1 is run, the vehicle is inevitably stopped, and at the time of deceleration accompanying this stop, the mud and water dripping on the upper surface 59 has an inertial force toward the front of the vehicle. The inclined surface provided on the upper surface portion 59 always efficiently flows out to the front side of the vehicle and is excreted. Therefore, mud and water do not accumulate on the upper surface portion 59 of the rear swing arm 17, and the unsprung weight of the motorcycle 1 is increased, causing no deterioration in motion performance. It accumulates on the upper surface part 59 of the rear swing arm 17 over the entire area, and there is no inconvenience in appearance and no reduction in strength due to rusting.

  Further, according to the rear swing arm 17, there is no need to provide a hole for discharging mud and water dripped on the upper surface portion 59 of the central connecting member 56. Therefore, the strength and rigidity of the rear swing arm 17 are not impaired, and the man-hours and processes associated with the formation of the holes can be reduced, so that productivity can be improved.

  Therefore, according to the rear swing arm 17 according to the present embodiment, it is possible to provide the rear swing arm 17 of the motorcycle 1 in which mud and water do not accumulate on the front connection member 42 while ensuring high strength and rigidity. .

The left side view which shows the motorcycle in which an example of embodiment of the rear swing arm which concerns on this invention was used. 1 is a partial longitudinal sectional view of a motorcycle in which an example of an embodiment of a rear swing arm according to the present invention is used. The perspective view which shows an example of embodiment of the rear swing arm which concerns on this invention. The perspective view which shows the other example of embodiment of the rear swing arm which concerns on this invention. The perspective view which shows the other example of embodiment of the rear swing arm which concerns on this invention. The perspective view which shows an example of the conventional rear swing arm used for a motorcycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 3 V-type engine 4 Fuel tank 5 Seating seat 6 Rear fender 7 Passenger seat 8 Step 9 Radiator 10 Front wheel 11 Front fork 12 Handle bar 14 Front fender 15 Swing pivot shaft 16 Rear wheel 17 Rear swing arm 19 Transmission 22 Head pipe 23 Main frame 24 Down tube 26 Front bridge member 27 Upper bridge member 28 Lower bridge member 30 Pivot bracket portion 31 Pivot shaft support portion 32 Rear fender bracket 33 Mudguard member 35 Article storage portion 36 Article storage portion wall 36a Front wall 36b Bottom Wall 36c Rear wall 38 Battery 40, 41 Arm portion 42 Front connection member 44, 50 Pivot shaft support portion 45, 51 Arm front half portion 46, 52 Upper member 47, 53 Lower member 48 Shaft case 54 Rear wheel bearing part 56 Center part connecting member 57 Upper half part connecting member 58 Lower half part connecting member 59 Upper surface part 60 Groove 70 Conventional rear swing arm

Claims (3)

A seat seat placed on the body frame;
In a swing arm of a motorcycle having an article storage portion provided in a vehicle body frame located below the seating seat,
A front half of the arm formed in a substantially triangular shape in a side view extending vertically from the front end portion toward the rear end portion having a pivot shaft support portion through which the swing pivot shaft is passed;
An upper member extending obliquely downward from the upper end of the front half of the arm;
A lower member extending obliquely upward from the lower end of the front half of the arm,
A pair of left and right arms that pivotally support the rear wheel at the rear end;
A central connection member erected in a substantially central portion in the vertical direction of the front half of the arm;
A front connection member having an upper half connection member constructed on the upper half of the rear end of the arm front half,
The central part in the vehicle width direction of the front connecting member is
An L-shaped recess that opens forward and upward is formed by the central portion connecting member and the upper half portion connecting member, and the article storage portion can appear and disappear.
The central connecting member is
A rear swing arm of a motorcycle having an upper surface portion inclined from the rear upper side toward the front lower side. The upper surface portion of the central connecting member is
Inclined from the vehicle width direction upper center to the vehicle width direction outer lower side, and has a concave groove formed by a surface inclined from the rear upper side to the front lower side at the vehicle width direction outer end. The rear swing arm of the motorcycle according to claim 1. The upper surface portion of the central connecting member is
Inclined from the upper end of the vehicle width direction toward the lower center of the vehicle width direction, and has a concave groove formed by a surface inclined from the upper rear to the lower front direction at the central portion in the vehicle width direction. The rear swing arm of the motorcycle according to claim 1.

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