JP2012240491A - Engine suspension structure of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a change in a maneuvering characteristic, while reducing vibration of an engine, in an engine suspension structure of a motorcycle.SOLUTION: This engine suspension structure of the motorcycle includes a vehicle body frame 2, the engine 30 for arranging a cylinder shaft C in the substantially horizontal direction, link members 70 and 70 for connecting the vehicle body frame 2 and the engine 30, and a swing arm 12 having a support shaft 18B on the engine 30 side to the link members 70 and 70 and rotatably suspending a rear wheel 4. The vehicle body frame 2 and the engine 30 are rockably connected in the vertical direction by a pair of right-left link members 70 and 70 arranged in the rear of the engine 30. Rocking restraining connecting parts 80 and 80 for connecting the vehicle body frame 2 and the engine 30 via a rubber bush 87, are arranged in front of the link members 70 and 70 so as to allow the relative movement of the vehicle body frame 2 and the engine 30 only in a predetermined range.

Description

  The present invention relates to an engine suspension structure for a motorcycle including a link member that connects a vehicle body frame and an engine.

  Conventionally, in an engine suspension structure for a motorcycle, an engine having a horizontal cylinder shaft is suspended on a vehicle body frame via a parallel link including a first link on the front side of the engine and a second link on the rear side of the engine to support the rear wheels. There is known a structure in which a swing arm supporting shaft is provided at the rear of a second link to suppress vibrations in the front and rear of the engine transmitted to the body frame (for example, see Patent Document 1).

JP 58-56989 A

However, in the conventional engine suspension structure of the motorcycle described above, the engine and the swing arm are fixed to the vehicle body frame via the parallel links. There is a problem that the steering characteristics of the vehicle change. For this reason, it is necessary to develop a vehicle that takes into account changing steering characteristics, and the development period increases.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it possible to reduce changes in steering characteristics while reducing engine vibration in an engine suspension structure of a motorcycle.

To achieve the above object, the present invention provides a vehicle body frame (2), an engine (30) in which a cylinder shaft (C) is arranged in a substantially horizontal direction, the vehicle body frame (2), and the engine (30). A link member (70, 70) for connecting the two and a support shaft (18B) on the engine (30) side with respect to the link member (70, 70), and the rear wheel (4) is rotatably suspended. In an engine suspension structure of a motorcycle including a swing arm (12), the body frame (2) and the engine (30) are provided by a pair of left and right link members (70, 70) provided at the rear of the engine (30). ) In a vertically movable manner, and the relative movement between the body frame (2) and the engine (30) is allowed only within a predetermined range in front of the link members (70, 70). In addition, Characterized by providing the body frame (2) and the engine (30) and the swinging motion restraint connecting portion connecting via sexual member (87) (80, 80).
According to this configuration, the engine in which the cylinder shaft is arranged in a substantially horizontal direction, the link member that connects the vehicle body frame and the engine, the support shaft on the engine side with respect to the link member, and the rear wheels are rotatable. The vehicle body frame and the engine are swingably connected to each other in a vertical direction by a pair of left and right link members provided at the rear of the engine. Since the swing suppression connecting portion that connects the vehicle body frame and the engine via the elastic member is provided so as to allow the movement only within a predetermined range, the vibration of the engine in the cylinder axial direction is caused by the engine via the link member. The vibration of the engine at this time is reduced only by a predetermined range relative to the vehicle body frame by the rocking suppression connecting portion in front of the link member. Order to be acceptable, it is possible to reduce a change in the geometry of the vehicle. For this reason, it is possible to reduce changes in steering characteristics while reducing engine vibration.

In the above configuration, the link support shaft (18A) of the link member (70, 70) on the engine (30) side and the support shaft (18B) of the swing arm (12) may be coaxial. good.
In this case, the link support shaft on the engine side of the link member and the support shaft of the swing arm are coaxial, and the torsional force input to the swing arm is directly input to the link member. The force can be received, and the torsional resistance of the swing arm can be improved.

Further, the engine side bracket (50) connected to the engine (30) is provided with a swing suppression connecting portion (49, 49) on the engine (30) side and the link support shaft (18A), and the link support is provided. A cylindrical member (55) for connecting the left and right side surfaces (51, 51) of the engine side bracket (50) coaxially with the shaft (18A) and the support shaft (18B) of the swing arm (12) may be provided. .
In this case, the link support shaft is disposed on the engine side bracket, and a cylindrical member that connects the left and right side surfaces of the engine side bracket coaxially with the link support shaft and the support shaft of the swing arm is provided. The rigidity and strength of the portion around the arm spindle can be increased.

Furthermore, it is good also as a structure by which the said rocking | fluctuation suppression connection part (80,80) is arrange | positioned on the vertical line (V) passing through the gravity center position (G1) of the said engine (30).
In this case, the vibration suppression connecting portion is arranged on a vertical line passing through the center of gravity of the engine, and the vibration of the engine can be limited at a position close to the center of gravity of the engine, so that the vibration can be effectively suppressed.
Furthermore, the vehicle body frame (2) includes a single main frame (14) and other frame members, and extends to the side of the main frame (14). A swing suppression connecting portion (80, 80) is provided, and the swing suppression connecting portion on the engine (30) side is provided between the main frame (14) and the vehicle body frame side swing suppression connecting portion (80, 80). (49, 49) may be arranged.
In this case, the vehicle body frame has a single main frame, and is provided with a vehicle body frame side swing suppression connecting portion extending laterally on the side surface side of the main frame. Since the engine-side swing suppression connecting portion is disposed between the two and the engine is suspended at a position outside the single main frame in the vehicle width direction, the torsional rigidity of the vehicle body can be improved.

In addition, a head pipe (13) for holding the front wheel (3) on the vehicle body frame (2) so as to be steerable is provided, and when viewed from the side, the head pipe (13) and the swing suppression connecting portion (80, 80). ), The support shaft (18B) of the swing arm (12), and the ground contact point (R) of the rear wheel (4) may be arranged in a straight line.
In this case, in the side view, the head pipe, the swing suppression connecting portion, the support shaft of the swing arm, and the grounding point of the rear wheel are arranged in a straight line, and the path connecting the front wheel side and the rear wheel is in a straight line. Therefore, the influence of the disturbance from the road surface on the steering can be reduced.

The engine (30) is configured from the front in order of a cylinder head (31), a cylinder (32), and a crankcase (33) incorporating a crankshaft and a transmission mechanism. It is good also as a structure by which the said rocking | fluctuation suppression connection part (80,80) is arrange | positioned.
In this case, the engine is configured from the front in the order of the cylinder head, the cylinder, and the crankcase. The swing suppression connecting portion is disposed above the crankcase, and the engine swings above the large crankcase among the engine components. Since the movement suppressing connecting portion is arranged, the engine can be connected in a region where the clearance between the vehicle body frame and the engine is small, and the swing suppressing connecting portion can be configured without increasing the size of a bracket or the like for connecting the engine. For this reason, weight reduction and size reduction of the whole vehicle can be achieved.

  In the engine suspension structure for a motorcycle according to the present invention, the vehicle body frame and the engine are swingably connected in a vertical direction by a pair of left and right link members provided at the rear of the engine, and the vehicle body frame and the engine are disposed in front of the link member. Is provided with a swing suppression connecting portion that connects the vehicle body frame and the engine via an elastic member so as to allow the relative movement of the engine to a predetermined range only. Since the engine swing at this time is allowed to move relative to the vehicle body frame only within a predetermined range by the swing suppression connecting portion, the change in the geometry of the vehicle can be reduced. For this reason, it is possible to reduce changes in steering characteristics while reducing engine vibration.

Further, the link support shaft on the engine side of the link member and the support shaft of the swing arm are coaxial, and the torsional force on the swing arm is directly input to the link member, so that the torsional force is received by the vehicle body frame via the link member. And torsional resistance of the swing arm can be improved.
In addition, since a cylindrical member that connects the left and right side surfaces of the engine side bracket coaxially with the link support shaft and the swing arm support shaft is provided, the rigidity and strength of the peripheral portion of the link support shaft and the swing arm support shaft in the engine side bracket are provided. Can be increased.

Furthermore, since the swing suppression connecting portion is arranged on a vertical line passing through the center of gravity of the engine and can limit the vibration of the engine at a position close to the center of gravity of the engine, the vibration can be effectively suppressed.
Furthermore, an engine-side swing suppression connecting portion is disposed between the main frame and the vehicle body frame-side swing suppression connecting portion on the side of the main frame, and is positioned outside the single main frame in the vehicle width direction. Because the engine is suspended by the torsional rigidity of the vehicle body can be improved.

Further, in a side view, the head pipe, the swing suppression connecting portion, the swing arm support shaft, and the ground contact point of the rear wheel are arranged in a straight line, and the path connecting the front wheel side and the rear wheel is in a straight line. Therefore, the influence of the disturbance from the road surface on the steering can be reduced.
In addition, since the swing suppression connecting part is placed above the large crankcase among the engine components, the engine can be connected in a region where the clearance between the vehicle body frame and the engine is small, such as a bracket for connecting the engine. The swing suppressing connecting portion can be configured without increasing the size. For this reason, weight reduction and size reduction of the whole vehicle can be achieved.

1 is a left side view showing a motorcycle according to an embodiment of the present invention. It is a left view which shows the engine suspension structure with respect to a vehicle body frame. It is the figure which looked at the circumference of an engine from the lower part. It is the top view which looked at the body frame and the engine from the upper part. It is the perspective view which looked at the engine suspension mechanism part from the lower side. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the up / down, front / rear, and left / right directions are directions seen from the driver of the vehicle.
FIG. 1 is a left side view showing a motorcycle according to an embodiment of the present invention.
In the motorcycle 1, an engine 30 is disposed in the center of the front and rear of the body frame 2, a front fork 11 that supports the front wheel 3 is supported at the front end of the body frame 2, and a swing arm 12 that supports the rear wheel 4 is provided. This is a saddle-ride type vehicle provided on the rear side of the body frame 2.

FIG. 2 is a left side view showing a suspension structure of the engine 30 with respect to the vehicle body frame 2.
As shown in FIGS. 1 and 2, the vehicle body frame 2 includes a head pipe 13 at the front of the vehicle body, a single main frame 14 extending obliquely downward from the head pipe 13 to the rear, and other frames. And have. The other frames are a pair of left and right seat rails 15, 15 that extend obliquely upward from the rear end of the main frame 14 toward the rear, bend substantially horizontally in the middle and reach the rear end, the rear portion of the main frame 14, and each seat A pair of left and right reinforcing frames 16, 16 are provided between the rails 15, 15. The main frame 14 is a pipe-shaped frame having a rectangular cross section.
An engine side bracket 50 that supports the engine 30 is connected to the rear portion of the main frame 14.

A pair of left and right front forks 11, 11 are pivotally supported on the head pipe 13 via a steering shaft (not shown), and the front wheel 3 is pivotally supported on the lower portion of the front forks 11, 11. The handle 17 is provided above the steering shaft.
The swing arm 12 extending rearward is swingably supported at its front end by a pivot shaft 18, and the pivot shaft 18 extending in the vehicle width direction is supported by an engine side bracket 50. The rear wheel 4 is pivotally supported at the rear end of the swing arm 12, and a pair of left and right rear cushions 19, 19 are spanned between the rear portion of the swing arm 12 and the rear portions of the seat rails 15, 15.
One end of a pair of left and right link members 70, 70 extending downward is connected to the rear portion of the main frame 14, and the other end of the link members 70, 70 is pivotally supported on the pivot shaft 18 together with the swing arm 12.

As shown in FIG. 1, a storage box 5 is provided above the reinforcing frames 16, 16, and a driver's seat 6 is disposed on the upper surface of the storage box 5. The fuel tank 7 is provided below the seat 6 behind the storage box 5.
A stand 20 is provided below the engine side bracket 50. The vehicle body frame 2 is covered with a synthetic resin vehicle body cover 21 (partially not shown) divided into various parts.

  An engine 30 that is an internal combustion engine is suspended below the main frame 14 and in front of the swing arm 12. The engine 30 is a power unit that is integrally provided with a transmission, and is supported by an engine suspension mechanism 48 provided at the rear portion of the main frame 14 so as to be suspended below the rear portion of the main frame 14.

The engine 30 is a single-cylinder four-cycle engine, and is a horizontal engine that is largely inclined forward to a state where the cylinder axis C is substantially horizontal. The engine 30 is configured in the order of a cylinder head 31, a cylinder 32, a crankshaft (not shown), and a crankcase 33 incorporating a speed change mechanism (not shown) in order from the front side. Since the engine 30 is a horizontal engine, the vehicle body can be lowered in the center of gravity, and as shown in the figure, the main frame 14 can be lowered to lower the straddling portion M on which the driver straddles when getting on, thereby improving boarding / exiting performance. Further, in the engine 30, the cylinder shaft C is substantially horizontal and extends forward, so that a piston (not shown) reciprocates back and forth, and vibration of the engine 30 occurs mainly in the front-rear direction.
An output shaft 34 of the engine 30 protrudes from the left side surface of the rear portion of the crankcase 33, and the rear wheel 4 is between a drive gear 43 (FIG. 1) fixed to the output shaft 34 and a driven gear 44 of the rear wheel 4. It is driven by a drive chain 45 that is stretched over the belt. The engine 30 is an engine having an automatic transmission mechanism, and transmission and power are transmitted between the crankshaft and the output shaft 34 via a variable pulley and a belt (not shown) wound around the variable pulley.

As shown in FIG. 1, the air cleaner box 35 is disposed below the front portion of the main frame 14, and the throttle body 36 extends from the lower portion of the air cleaner box 35 and is connected to the upper portion of the cylinder head 31.
An exhaust pipe 37A is connected to the lower part of the cylinder head 31. The exhaust pipe 37A extends downward, then bends and extends rearward, and is attached to a muffler 37B disposed on the right side of the swing arm 12 and the rear wheel 4. Connected. The exhaust pipe 37 </ b> A and the muffler 37 </ b> B constitute an exhaust device 38.

Subframes 39 and 40 extending to the lower side of the engine 30 are provided at the front portion and the middle portion of the main frame 14, and a plate-like floor step 41 on which the driver puts his feet is a lower portion of the subframes 39 and 40. It is supported by. A pair of left and right subframes 39 and 40 and a floor step 41 are provided.
A headlight unit 42 is provided at the front portion of the head pipe 13.

FIG. 3 is a view of the periphery of the engine 30 as viewed from below.
As shown in FIG. 3, a frame-shaped step support frame 46 is provided at the lower end of the sub-frame 40, and floor steps 41 extending in the front-rear direction are provided on the left and right sides of the step support frame 46. 46 is supported.
The swing arm 12 has a right arm 22 extending to the right side of the rear wheel 4 (FIG. 1) and a left arm 23 extending to the left side of the rear wheel 4, and the right arm 22 and the left arm 23 are arranged in the vehicle width direction. It is connected at the front by an extending cross member 24. At the front ends of the right arm 22 and the left arm 23, cylindrical shaft support portions 25, 25 that are supported by the pivot shaft 18 are provided.
The crankcase 33 includes a case body 33A that is connected to the cylinder 32 and supports the crankshaft, and case covers 33B and 33C that cover the left and right sides of the case body 33A.

FIG. 4 is a plan view of the body frame 2 and the engine 30 as viewed from above. FIG. 5 is a perspective view of the engine suspension mechanism 48 viewed from below. In FIG. 5, the illustration of the engine 30 is omitted.
As shown in FIGS. 2, 4, and 5, the engine suspension mechanism 48 includes an engine side bracket 50, link members 70, 70, and a swing suppression that connects the front side of the engine side bracket 50 to the main frame 14. Connecting portions 80 and 80 (body frame side swing suppressing connecting portion).
The engine side bracket 50 extends in the vehicle width direction across a pair of side plate portions 51 and 51 (left and right side surfaces of the engine side bracket) located on the left and right sides of the main frame 14 and the main frame 14, and the left and right side plate portions 51, and a plate portion 52 for connecting 51.

The engine-side bracket 50 has a front connecting portion 53 that extends rearward along the lower surface of the rear portion of the main frame 14 and a pivot plate portion 54 that is bent from the rear portion of the front connecting portion 53 and extends downward. doing.
As shown in FIG. 4, at the front part of the front connecting part 53, the inner side surfaces of the side plate parts 51, 51 are connected to connecting parts 49, 49 (swing on the engine side) to which the swing suppressing connecting parts 80, 80 are connected. (Suppressing connection part) is provided. The connecting portions 49, 49 have holes that penetrate the side plate portions 51, 51, and nuts 49 </ b> A that communicate with the holes and are welded to the inner side surfaces of the side plate portions 51, 51. Further, the connecting portions 49 and 49 are located above the plate portion 52.

A connecting pipe 55 (cylindrical member) inserted into and fixed to the left and right side plate portions 51, 51 is provided at the upper and lower intermediate portions of the pivot plate portion 54, and the side plate portions 51, 51 are connected by the connecting pipe 55. As a result, the rigidity of the engine side bracket 50 is enhanced. The connecting pipe 55 has projecting pipe portions 55A and 55A projecting outward from the side plate portions 51 and 51, and the projecting pipe portions 55A and 55A are disposed so as to be sandwiched from the outside by the shaft support portions 25 and 25 of the swing arm 12. Is done.
Further, a cross pipe 54 </ b> A (FIG. 3) for connecting the side plate portions 51, 51 is provided below the connection pipe 55 in the pivot plate portion 54.

Bolt support portions 56A and 56A are provided below the connection portions 49 and 49 of the side plate portions 51 and 51, and the left and right bolt support portions 56A and 56A are engine support provided between the side plate portions 51 and 51. Bolt 57A is inserted. The bolt support portions 56 </ b> A and 56 </ b> A are located below the plate portion 52.
Bolt support portions 56B and 56B are provided on the side plate portions 51 and 51 at the upper part of the pivot plate portion 54, and engine support bolts provided between the side plate portions 51 and 51 are provided on the left and right bolt support portions 56B and 56B. 57B is inserted.
Bolt support portions 56C and 56C are provided on the side plate portions 51 and 51 below the pivot plate portion 54, and engine support bolts provided between the side plate portions 51 and 51 are provided on the left and right bolt support portions 56C and 56C. 57C is inserted.

As shown in FIG. 2, the engine 30 has a fixed portion 30A through which the engine support bolt 57A is inserted at the top of the crankcase 33, and the fixed portions 30B and 30C through which the engine support bolts 57B and 57C are inserted. 33 at the rear. The engine 30 is fixed to the engine side bracket 50 with three points by three fixing portions 30A, 30B, and 30C.
A plurality of lightening holes 52A are formed in the plate portion 52 to reduce the weight.

6 is a cross-sectional view taken along the line VI-VI in FIG.
As shown in FIGS. 4 to 6, a single pipe-shaped link connecting shaft 71 that extends through the main frame 14 in the vehicle width direction is provided at the rear of the main frame 14. Further, the link connecting shaft 71 is connected to the reinforcing frames 16 and 16 by reinforcing plates 16A and 16A extending upward from the link connecting shaft 71, and is joined by a welded portion 71A formed in a penetrating portion on the side surface of the main frame 14. Has been. Since the link connecting shaft 71 penetrates the main frame 14 and is reinforced by the reinforcing plates 16A and 16A, the link connecting shaft 71 has high rigidity and strength.
The link connecting shaft 71 is provided between the front end portions of the reinforcing frames 16 and 16 and the front end portions of the seat rails 15 and 15 in a side view. Link members 70 are connected to the left and right ends of the link connecting shaft 71.

Each of the link members 70 includes a cylindrical frame side connecting portion 72 connected to the link connecting shaft 71, a cylindrical pivot side connecting portion 73 connected to the pivot shaft 18, a frame side connecting portion 72 and a pivot. It has the connection pipe part 74 which connects the side connection part 73 up and down. The link members 70 are pivotally supported around a swing shaft 76 inserted through the left and right frame side connection portions 72 and the link connection shaft 71.
The frame side connecting portion 72 is pivotally supported on the end of the swing shaft 76 via a tubular rubber bush 75A fitted in the frame side connecting portion 72. Each frame-side connecting portion 72 is located outside the left and right side surfaces of the case main body 33A of the crankcase 33 in the vehicle width direction.

As shown in FIG. 6, the rubber bush 75 </ b> A includes a cylindrical outer tube 60, an inner tube 61 disposed inside the outer tube 60, and a tubular body interposed between the outer tube 60 and the inner tube 61. Anti-vibration rubber 62. The length of the inner tube 61 in the axial direction is longer than the length of the outer tube 60 and the vibration isolating rubber 62 in the axial direction, and both ends of the inner tube 61 protrude from both ends of the outer tube 60.
The rubber bush 75 </ b> A is disposed so that the outer tube 60 is fitted to the inner peripheral surface of the frame-side connecting portion 72, and is supported by a swing shaft 76 inserted through the inner tube 61. Further, the rubber bush 75A is positioned in the axial direction by the inner end of each inner tube 61 coming into contact with the end face of the link connecting shaft 71, and in this state, the nut 76A is fastened to the end of the swing shaft 76. Thus, the inner tube 61 is abutted and fixed between the head of the swing shaft 76 and the nut 76A.

  As shown in FIGS. 4 and 6, the connection pipe portion 74 extends downward while spreading in the vehicle width direction, and the pivot side connection portion 73 connected to the lower end of the connection pipe portion 74 is a frame side connection portion 72. It is located outside the vehicle width direction. Each pivot side connecting portion 73 is disposed so as to sandwich the shaft support portions 25, 25 of the swing arm 12 from the outside, and is attached to the end of the pivot shaft 18 via a tubular rubber bush 75 B fitted in the pivot side connecting portion 73. It is pivotally supported. The rubber bush 75B is the same component as the rubber bush 75A, and includes an outer tube 60, an inner tube 61, and a vibration isolating rubber 62. A washer 77 is provided on the outer end side of the rubber bush 75B.

Stepped cylindrical collars 26 and 26 are provided at both ends of the shaft support portion 25 of the swing arm 12. The cylindrical collars 26 and 26 are positioned in the axial direction when the step portion 26 </ b> A contacts the end surface of the shaft support portion 25. The swing arm 12 is pivotally supported by the pivot shaft 18 through the support holes 26B of the cylindrical collars 26 and 26.
Cylindrical collars 58 and 58 are fitted to both ends of the connection pipe 55 of the engine side bracket 50. The collars 58 and 58 are axially positioned by a pipe-like spacer 59 disposed between the collars 58 and 58.

  The rubber bush 75 </ b> B is arranged so that the outer tube 60 is fitted to the inner peripheral surface of the pivot side connecting portion 73, and is supported by the pivot shaft 18 inserted through the inner tube 61. The rubber bush 75B is positioned in the axial direction by the inner end of each inner tube 61 coming into contact with the outer end surface of the cylindrical collar 26. In this state, the nut 18C is fastened to the end of the pivot shaft 18, An inner tube 61 is abutted and fixed between the head of the pivot shaft 18 and the nut 18C.

  In the swing arm 12, the pivot support 25 is disposed between the projecting pipe portion 55 </ b> A and the pivot side connection portion 73, and the single pivot shaft 18 passing through the connection pipe 55, the shaft support portion 25, and the pivot side connection portion 73. It is pivotally supported by. That is, the pivot shaft 18 serves as both the link support shaft 18A for supporting the link members 70 and 70 on the engine 30 side and the support shaft 18B for supporting the swing arm 12, and the pivot support shaft 18A and the support shaft 18A. The shaft 18B has a coaxial positional relationship.

As shown in FIGS. 4 and 5, a pipe-like frame side connecting shaft 81 extending through the side surface of the main frame 14 in the vehicle width direction and extending to the left and right sides is provided at the front and rear intermediate portions of the main frame 14. 82 are provided side by side, and the swing suppression connecting portions 80 and 80 are connected to the frame side connecting shafts 81 and 82. The frame-side connecting shafts 81 and 82 are provided as a single piece penetrating the main frame 14 and are welded to the main frame 14 at the penetrating portion on the side surface of the main frame 14, so that the strength and rigidity are high.
Each swing suppression connecting portion 80 includes a support plate portion 83 provided so as to face the side surface of the main frame 14, and a cylindrical connection tube 84 that extends through the support plate portion 83 in the vehicle width direction. ing. The connecting tube 84 is fixed by welding the connecting tube 84 to the support plate 83 in this state by engaging the connecting tube 84 with a notch formed in the lower part of the supporting plate 83.

  Bolt support portions 85 and 86 are provided in front and rear of the connection pipe 84 in the support plate portion 83. The bolt support portions 85 and 86 are provided with swing suppression connection portions 80 and 80 and frame side connection shafts 81 and 82. Bolts 85 </ b> A and 86 </ b> A that are fastened to are inserted. Specifically, each swing suppression connecting portion 80 is arranged such that the inner surface of the support plate portion 83 abuts against the end surfaces of the frame side connecting shafts 81 and 82, and the bolt support portions 85 and 86 and the frame side from one side. Bolts 85 </ b> A and 86 </ b> A are inserted through the connecting shafts 81 and 82, and nuts 85 </ b> B and 86 </ b> B are fastened to the other side surface to be fixed to the main frame 14.

Since the frame side connecting shafts 81 and 82 extend in the vehicle width direction, a space is secured between the inner end of the connecting pipe 84 and the side surface of the main frame 14, and the engine side bracket 50 is connected to this space. Parts 49, 49 are arranged.
A tubular rubber bush 87 (elastic member) shown in FIG. 5 is fitted in each connecting pipe 84 of the swing suppression connecting portion 80, and the nut 49 </ b> A of the connecting portion 49 of the engine side bracket 50 is fitted into the rubber bush 87. Bracket fixing bolts 88 fastened to are inserted from the outside. That is, each swing suppression connecting portion 80 is connected to the engine side bracket 50 via the rubber bush 87 located outside the main frame 14.
In the present embodiment, since the engine side bracket 50 is connected to the main frame 14 at a position outside the main frame 14, the torsional rigidity of the vehicle body frame 2 can be improved.

7 is a cross-sectional view taken along the line VII-VII in FIG.
As shown in FIG. 7, each rubber bush 87 is interposed between a cylindrical outer tube 90, an inner tube 91 disposed inside the outer tube 90, and the outer tube 90 and the inner tube 91. And a tubular antivibration rubber 92. The length of the inner tube 91 in the axial direction is longer than the length of the outer tube 90 and the antivibration rubber 92 in the axial direction, and both ends of the inner tube 91 protrude from both ends of the outer tube 90. The rubber bush 87 is the same component as the rubber bushes 75A and 75B.

The rubber bush 87 is disposed so that the outer tube 90 is fitted to the inner peripheral surface of the connecting tube 84, and is supported by a bracket fixing bolt 88 inserted through the inner tube 91. Further, the rubber bush 87 is positioned in the axial direction by the inner end of each inner pipe 91 contacting the outer surface of the side plate portion 51 of the engine side bracket 50, and in this state, the bracket fixing bolt 88 is fastened. The inner pipe 91 is abutted and fixed between the head of the bracket fixing bolt 88 and the connecting portion 49.
In other words, the front connection portion 53 of the engine side bracket 50 is rubber-mounted on the frame side connection shafts 81 and 82 of the main frame 14 via the rubber bush 87, and when the external force is applied, the vibration isolation rubber 92 is bent. The engine side bracket 50 can move in the radial direction of the rubber bush 87 as much as possible.

As shown in FIG. 2, the engine 30 including the exhaust device 38 is suspended from the main frame 14 by an engine-side bracket 50, and link members 70, 70 extending in the vertical direction so as to be substantially orthogonal to the vibration direction of the engine 30 at the rear part. Thus, the link connecting shaft 71 is supported so as to be able to swing back and forth, and the front swing suppression connecting portions 80 and 80 are fixed by rubber mounts via rubber bushes 87. For this reason, the engine 30 including the exhaust device 38 can swing back and forth via the link members 70, 70, but the movable range is predetermined by the rubber bush 87 in the front swing suppression connecting portions 80, 80. Limited to the range of Here, the predetermined range corresponds to the amount of deflection in the radial direction of the vibration-proof rubber 92.
The vibrations in the front and rear of the engine 30 are transmitted to the vehicle body frame 2 after being attenuated by the vibration of the engine 30 back and forth via the swing suppression connecting portions 80 and 80 and the link members 70 and 70.

  As shown in FIG. 1, the center of gravity G1 of the engine 30 including the exhaust device 38 is located at the approximate center before and after the crankcase 33, and the swing suppression connecting portions 80 and 80 are perpendicular to the center of gravity G1. Located above line V. Thus, by arranging the rocking | fluctuation suppression connection parts 80 and 80 on the vertical line V which passes through the gravity center position G1, while being able to prevent the load which is biased to the rocking | fluctuation suppression connection parts 80 and 80 acting, it can prevent engine Since 30 can swing substantially uniformly in the front-rear direction, the vibration of the engine 30 can be effectively damped. Furthermore, since the vibration of the engine 30 can be limited at a position close to the gravity center position G1 of the engine 30, the vibration can be effectively suppressed.

  Further, among the components of the engine 30, the swing suppression connecting portions 80, 80 are arranged above the crankcase 33 having the largest vertical size, so that the clearance between the main frame 14 and the engine 30 is small. The engine 30 and the main frame 14 can be connected, and the engine-side bracket 50 and the swing suppression connecting portions 80 and 80 can be configured in a small size. For this reason, the motorcycle 1 can be reduced in weight and size.

  When the motorcycle 1 accelerates and decelerates, the heavy engine 30 moves relative to the main frame 14 due to inertia. For example, when the motorcycle 1 decelerates, the engine 30 and the engine side bracket 50 receive a force that swings forward with respect to the main frame 14 via the swing suppression connecting portions 80 and 80 and the link members 70 and 70. Accordingly, a force that moves forward acts on the swing arm 12 connected to the engine side bracket 50 via the pivot shaft 18. For this reason, when accelerating and decelerating, the geometry of the motorcycle 1 changes and the steering characteristics change.

In the present embodiment, link members 70 are provided at the rear part of the engine side bracket 50 so that the engine 30 can be swung back and forth, and the swing suppression is provided with a rubber bush 87 at the front part of the rear part of the engine side bracket 50. Since the connecting portions 80, 80 are provided and the relative movement of the engine 30, the engine side bracket 50, and the swing arm 12 with respect to the main frame 14 is allowed only within a predetermined range, the swing arm is suppressed while suppressing vibration of the engine 30. Thus, the change in geometry during acceleration and deceleration of the motorcycle 1 can be reduced by suppressing the back and forth movement of 12, and the change in steering characteristics can be reduced.
Since the vibration of the engine 30 can be suppressed, the vibration of the floor step 41 supported on the step support frame 46 can be reduced.

  Further, the link support shaft 18A on the engine 30 side of the link members 70 and 70 and the support shaft 18B of the swing arm 12 are constituted by the pivot shaft 18 and are coaxial, and the torsional force input to the swing arm 12 is input to the link member 70, 70. 70, it is possible to receive a torsional force at the vehicle body frame 2 via the link members 70, 70. For example, as compared with a configuration in which the swing arm 12 is pivotally supported at another location of the engine side bracket 50. Thus, the twist resistance of the swing arm 12 can be improved.

As shown in FIG. 1, in the motorcycle 1, in the side view, the head pipe 13, the swing suppression connecting portions 80 and 80, the pivot shaft 18 of the swing arm 12, and the grounding point R of the rear wheel 4 are: They are arranged on a straight line L passing through the head pipe 13 and the grounding point R, and are arranged in a straight line. The disturbance force from the road surface acting from the ground contact point F of the front wheel 3 acts on the head pipe 13 through the front fork 11, and then the swing suppression connecting portions 80, 80, the pivot shaft 18, and the rear wheel 4. The grounding point R acts in this order, and the force transmission path between the head pipe 13 and the rear wheel 4 is in a straight line. As a result, it takes less time to transmit the disturbance from the road surface to the vehicle body than when the transmission path is bent. Therefore, the influence of the disturbance from the road surface on the steering can be reduced, and the steering characteristics are good.
The center of gravity G2 of the entire motorcycle 1 is arranged on the straight line L. Thus, since the entire center of gravity G2 is on the transmission path of the disturbance, the steering characteristics are good.

  As described above, according to the embodiment to which the present invention is applied, the engine 30 in which the cylinder shaft C is arranged in the substantially horizontal direction, and the link member 70 that connects the main frame 14 of the body frame 2 and the engine 30. , 70, and a swing arm 12 having a support shaft 18B on the engine 30 side with respect to the link members 70, 70, and rotatably suspending the rear wheel 4, and a pair of left and right links provided at the rear of the engine 30 The main frame 14 and the engine 30 are swingably connected in the vertical direction by the members 70 and 70, and relative movement between the main frame 14 and the engine 30 is allowed only within a predetermined range in front of the link members 70 and 70. As described above, since the swing suppression connecting portions 80 and 80 that connect the main frame 14 and the engine 30 via the rubber bush 87 are provided, the cylinder axis C direction The vibration of the engine 30 is reduced by the swing of the engine 30 via the link members 70, 70, and the swing of the engine 30 at this time is caused by the swing suppression connecting portions 80, 80 in front of the link members 70, 70. Since the relative movement with respect to the main frame 14 is allowed only within a predetermined range, the amount of movement of the swing arm 12 can be reduced, and the change in the geometry of the motorcycle 1 can be reduced. For this reason, it is possible to reduce the change in the steering characteristics while reducing the vibration of the engine 30. In addition, the design is easy because it is not necessary to take into consideration the change in the steering characteristics due to the change in geometry.

Further, the link support shaft 18A on the engine 30 side of the link members 70 and 70 and the support shaft 18B of the swing arm 12 are coaxial, and the input of the torsional force to the swing arm 12 is directly input to the link members 70 and 70. The torsional force can be received by the vehicle body frame 2 via the link members 70 and 70, and the torsional resistance of the swing arm 12 can be improved.
A link support shaft 18A is disposed on the engine side bracket 50, and a connection pipe 55 that connects the left and right side plate portions 51, 51 of the engine side bracket 50 coaxially with the link support shaft 18A and the support shaft 18B of the swing arm 12 is provided. Therefore, the rigidity and strength of the portions around the link support shaft 18A and the support shaft 18B in the engine-side bracket 50 can be increased.

Further, since the swing suppression connecting portions 80 and 80 are arranged on the vertical line V passing through the center of gravity position G1 of the engine 30 and the vibration of the engine 30 can be limited at a position close to the center of gravity position G1 of the engine 30, it is effective. Vibration can be suppressed. Further, since the engine 30 can swing substantially uniformly in the front-rear direction, the vibration of the engine 30 can be effectively damped.
Furthermore, the vehicle body frame 2 has a single main frame 14 and is provided with swing suppression connecting portions 80, 80 extending laterally on the side surface side of the main frame 14. The connecting portions 49, 49 on the engine 30 side are arranged between the portions 80, 80, and the engine 30 is suspended at a position outside the single main frame 14 in the vehicle width direction. Can be improved.

In addition, when viewed from the side, the head pipe 13, the swing suppression connecting portions 80, 80, the support shaft 18 </ b> B of the swing arm 12, and the grounding point R of the rear wheel 4 are arranged in a straight line. Since the path connecting the wheels 4 is straight, the influence of disturbance from the road surface on the steering can be reduced, and the steering characteristics are good.
The engine 30 is configured from the front in the order of the cylinder head 31, the cylinder 32, and the crankcase 33. The swing suppression connecting portions 80 and 80 are disposed above the crankcase 33, and are among the components of the engine 30. Since the swing suppression connecting portions 80, 80 are arranged above the large crankcase 33, the engine 30 can be connected in a region where the clearance between the vehicle body frame 2 and the engine 30 is small, and the engine side to which the engine 30 is connected is connected. The swing suppression connecting portions 80 and 80 can be configured without increasing the size of the bracket 50 and the like. For this reason, the motorcycle 1 can be reduced in weight and overall size.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 3 Front wheel 4 Rear wheel 12 Swing arm 13 Head pipe 14 Main frame 18A Link support shaft 18B Support shaft 30 Engine 31 Cylinder head 32 Cylinder 33 Crankcase 49, 49 Part)
50 Engine side bracket 51, 51 Side plate (left and right sides of the engine side bracket)
55 Connecting pipe (cylindrical member)
70, 70 Link member 80, 80 Swing suppression connecting portion (body frame side swing suppressing connecting portion)
87 Rubber bush (elastic member)
C Cylinder shaft G1 Center of gravity position R Grounding point V Vertical line

Claims (7)

A vehicle body frame (2), an engine (30) in which a cylinder shaft (C) is arranged in a substantially horizontal direction, and a link member (70, 70) connecting the vehicle body frame (2) and the engine (30). A motorcycle having a support shaft (18B) on the engine (30) side with respect to the link members (70, 70), and a swing arm (12) for rotatably suspending a rear wheel (4). In the engine suspension structure of
The vehicle body frame (2) and the engine (30) are swingably connected in a vertical direction by a pair of left and right link members (70, 70) provided behind the engine (30), and the link member ( 70, 70) and the vehicle body frame (2) via an elastic member (87) so as to allow relative movement between the vehicle body frame (2) and the engine (30) only within a predetermined range. An engine suspension structure for a motorcycle, comprising a swing suppression connecting portion (80, 80) for connecting the engine (30).   The link support shaft (18A) on the engine (30) side of the link member (70, 70) and the support shaft (18B) of the swing arm (12) are coaxial. Engine suspension structure for motorcycles.   The engine side bracket (50) connected to the engine (30) is provided with the swing suppression connecting portion (49, 49) on the engine (30) side and the link support shaft (18A), and the link support shaft ( 18A) and a cylindrical member (55) for connecting left and right side surfaces (51, 51) of the engine side bracket (50) coaxially with the support shaft (18B) of the swing arm (12). Item 2. The engine suspension structure of a motorcycle according to Item 2.   The engine for a motorcycle according to claim 1, wherein the swing suppression connecting portion (80, 80) is disposed on a vertical line (V) passing through a center of gravity (G1) of the engine (30). Suspension structure.   The vehicle body frame (2) includes a single main frame (14) and other frame members, and suppresses the vehicle body frame side swing that extends laterally to the side surface of the main frame (14). A connecting portion (80, 80) is provided, and the swing suppressing connecting portion (49, 49) on the engine (30) side is provided between the main frame (14) and the vehicle body frame side swing suppressing connecting portion (80, 80). 49. The engine suspension structure for a motorcycle according to claim 1, wherein 49) is arranged.   A head pipe (13) for holding the front wheel (3) on the vehicle body frame (2) so as to be steerable is provided, and when viewed from the side, the head pipe (13), the swing suppression connecting portion (80, 80), The engine of a motorcycle according to claim 2, wherein the support shaft (18B) of the swing arm (12) and the ground point (R) of the rear wheel (4) are arranged in a straight line. Suspension structure.   The engine (30) is configured in order of a cylinder head (31), a cylinder (32), and a crankcase (33) incorporating a crankshaft and a transmission mechanism from the front, and the engine (30) is disposed above the crankcase (33). The engine suspension structure for a motorcycle according to claim 6, wherein the swing suppression connecting portion (80, 80) is arranged.

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