JP2005271608A - Vehicular frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular frame in which a folding shape thereof is simplified, the strength and the rigidity are increased, and the vehicular appearance is enhanced by a vehicle body frame. <P>SOLUTION: In a vehicle 10 in which a front fork 14 is steerably mounted on a head pipe 12, a front wheel 16 is mounted on the front fork 14, and a main frame 21 as one frame extends backwardly from the head pipe 12, the main frame 21 has a shape that a letter S is laid horizontally in the longitudinal direction of the vehicle in side view, a bottom part 36a as a foot-crossing part and floor supporting parts 44 and 45 as foot rest parts are provided on a front arc part 36 which is projecting downwardly and provided on a front half part of the letter S, and an engine 27 is arranged in a lower space of a rear arc part 38 which is projecting upwardly and provided on a rear half part of the letter S. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle frame.

As a conventional vehicle frame, one in which a main frame is formed by bending is known (see, for example, Patent Document 1).
US Pat. No. 3,504,934

FIG. 5 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 12 is a side view of a vehicle equipped with a conventional frame, which is composed of a lower bent portion 302 bent downward of one main frame 301 of the vehicle and an upper bent portion 303 bent upward. A saddle 304 is attached to the upper bent portion 303, and a subframe assembly 307 is attached to an intermediate portion between the lower bent portion 302 and the upper bent portion 303 via a ball joint 306, and the rear portion of the main frame 301, more specifically, downward. The rear portion of the sub-frame assembly 307 is attached to the lower end of the portion 308 via the ball joint 311 and the rear wheel 312 is attached to the sub-frame assembly 307 via the axle.

  The lower bent portion 302 and the upper bent portion 303 of the main frame 301 are formed by bending a plurality of portions of the pipe into obtuse angles, and as a manufacturing method, for example, when bending one portion at a predetermined angle, a large number of man-hours are required for formation. Productivity is worsened. Productivity can be improved if the number of bent portions is reduced to simplify the bent shape and a similar downward projecting portion and upward projecting portion can be formed. Further, since it is a single main frame 301, it is desirable that its strength and rigidity be higher.

  Furthermore, when the main frame 301 is entirely exposed without being covered with a cover, or when a part of the main frame 301 is covered with a cover and a part is exposed to the outside, the main frame 301 has a favorable appearance. If it is a thing, the appeal as a product will be improved.

  SUMMARY OF THE INVENTION An object of the present invention is to simplify a bent shape of a vehicle frame, to further increase strength and rigidity, and to improve the appearance of a vehicle by a body frame.

  The invention according to claim 1 is a vehicle in which a front fork is attached to a head pipe in a steerable manner, a front wheel is attached to a lower end of the front fork, and one frame is extended rearward from the head pipe. The S-shape is laid sideways in the vehicle front-rear direction, and a leg straddle portion and a footrest portion are provided in the downwardly convex front arc portion provided in the front half portion of the S-shape, and provided in the latter half portion of the S-shape. Further, the engine is arranged in a space below the rear circular arc portion that is convex upward.

By making the frame one S-shaped frame, the frame can be smoothly bent into an arc shape, and the number of bent portions can be reduced.
Further, by exposing the whole or a part of one S-shaped frame to the outside, a slim and flowing appearance can be obtained.

The invention according to claim 2 is characterized in that the engine is attached to a swing arm extending rearward from a substantially middle portion of the S-shape of the frame.
Since the engine is located on the rear side of the S-shaped frame, a space for moving the engine up and down when the swing arm swings can be secured in the space below the rear arc portion along with the engine placement space.

The invention according to claim 3 is characterized in that the curvature radii of the front arc portion and the rear arc portion are the same.
By making the curvature radius of the front arc portion and the rear arc portion the same, for example, the front arc portion and the rear arc portion can be formed using the same bending jig, and the workability of the S-shaped frame can be improved. This can be further improved.

The invention according to claim 4 is characterized in that the frame is formed of a square pipe.
Since the frame consists of square pipes, for example, a square pipe with the same outer diameter, cross-sectional width, and height has a larger section modulus than a round pipe frame, so strength and rigidity can be increased. . Further, it is possible to easily weld the bracket to the flat surface of the square pipe, or to directly attach the parts with screws or the like.

The invention according to claim 5 is characterized in that a stopper with which the swing arm abuts is provided at the rear end of the S-shape of the frame.
It becomes easy to provide a stopper at the rear end of the S-shape of the frame, and the stopper can be brought into contact with the rear part of the swing arm.

  According to the first aspect of the present invention, since the frame is a single S-shaped frame, the frame can be smoothly bent into an arc shape, the number of bent portions can be reduced, and the workability of the frame can be improved. Therefore, the cost of the frame can be reduced.

  Moreover, if the whole or a part of one S-shaped frame is exposed to the outside, a slim and flowing appearance can be achieved, the appearance can be improved, and the merchantability can be improved. it can.

  In the invention which concerns on Claim 2, the vertical movement space of the engine when a swing arm swings can be ensured in the space below the rear arc portion together with the engine placement space. Thereby, the space of the vehicle can be used effectively, and the vehicle can be reduced in size and size.

  In the invention according to claim 3, by making the curvature radius of the front arc portion and the rear arc portion the same, it is possible to further improve the workability of the S-shaped frame and increase the productivity of the S-shaped frame. be able to. Therefore, the cost of the frame can be reduced.

  In the invention which concerns on Claim 4, since a flame | frame consists of a square pipe, intensity | strength and rigidity can be improved compared with the flame | frame which consists of a round pipe. In addition, since the frame is a square pipe, it is easy to weld brackets to the frame or attach parts directly with screws, etc., which can increase vehicle productivity and reduce vehicle cost. Can be reduced.

  In the invention according to claim 5, since the stopper can be easily provided at the rear end of the S-shape of the frame, and the stopper contacts the rear part of the swing arm, for example, the stopper contacts the front part of the swing arm. In contrast, according to the present invention, the swing of the swing arm can be reliably stopped.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a vehicle according to the present invention. In the vehicle 10, a steering stem 13 is rotatably attached to a head pipe 12 that constitutes a front end portion of a vehicle body frame 11, and a front fork 14 is mounted below the steering stem 13. A front wheel 16 is attached to the lower portion of the front fork 14, a handle post 17 is attached to the upper end of the steering stem 13, a handle 18 is attached to the handle post 17, and a vehicle body frame is formed in an S shape rearward from the head pipe 12. 11 is extended, a swing arm 22 made of a leaf spring is extended rearward from the center of the main frame 21, and an axle 23 is rotatably attached to the rear end of the swing arm 22. At each end, rear wheels 24 and 26 (only the reference numeral 24 on the front side is shown) are attached. An engine 27 is attached to the middle part of the swing arm 22, and the output of the engine 27 is transmitted to the rear wheels 24 and 26 by a chain 28. A main post 31 is attached to the rear part of the main frame 21, and can slide on the main post 31. This is a tricycle in which a seat post 32 is attached to the seat post 32 and a saddle 33 is attached to the seat post 32.

  The main frame 21 is composed of a square pipe, and extends from the head pipe 12 so as to form a circular arc in a convex shape downward from the lower end of the front linear portion 35, and the front linear portion 35 extending linearly downward from the head pipe 12. A front arc portion 36, a central straight portion 37 extending obliquely rearward and upward from the rear end of the front arc portion 36, and a rear portion extending in a convex arc from the rear end of the central straight portion 37 This is a member constituted by the arc portion 38.

The front straight part 35 is a part in which the tip is attached to the head pipe 12 and the attachment part is reinforced by the reinforcing members 41 and 42.
The front arc portion 36 is a portion where floor support portions 44 and 45 (only the reference numeral 44 on the front side is shown) for supporting a step floor (not shown) on which the driver 43 puts his / her foot on the bottom portion 36a is attached. The lowest part of the front arc part 36, that is, the bottom part 36a is a leg straddle part where the driver straddles his / her foot.

The front arc portion 36 and the central straight portion 37 are portions that support the swing arm 22.
The rear arc portion 38 is a portion where the main post 31 is attached to the top portion 38a.
The front arc portion 36 and the rear arc portion 38 described above are portions having the same arc radius for facilitating the manufacture of the main frame 21.

  Here, 51 is a front fender that covers the upper side of the front wheel 16, 52 and 53 are brake discs and brake calipers that constitute the front disc brake 54, and 56 and 57 are brake discs and brake calipers that constitute the rear disc brake 58.

  2 is a rear side view of the vehicle according to the present invention (the rear wheel 24 (see FIG. 1) on the front side is omitted). The main frame 21 has pivot plates 61 and 62 (the front pivot plate 61 is not provided). The pivot shaft 64 and the support shafts 65 and 66 are passed to the pivot plates 61 and 62, and one end of the swing arm 22 is wound around the pivot shaft 64 via the first bush 67 and swings in the vicinity of the pivot shaft 64. The arm 22 is sandwiched up and down by a second bush 68 and a third bush 69 attached to the support shafts 65 and 66, the other end of the swing arm 22 is wound around a bearing member (not shown), and an engine A drive sprocket 72 attached to an output shaft (not shown) of the engine 27, Indicating that looped chain 28 and driven sprocket 74 mounted via a sprocket support flange 73 to 23.

  Here, 76 is a first stopper attached to the main frame 21 and the pivot plates 61 and 62 for restricting the upward movement amount of the second bush 68, and 77 is a main frame for restricting the upward swing amount of the swing arm 22. 21 is a bolt for attaching the driven sprocket 74 to the sprocket support flange 73.

3A and 3B are cross-sectional views showing a swing arm mounting portion of a vehicle according to the present invention. FIG. 3A is a cross-sectional view taken along a plane orthogonal to the pivot shaft 64, and FIG. Is cut along the line.
In (a), the first bush 67 includes an inner cylinder 81 fitted to the pivot shaft 64, an outer cylinder 82 fitted inside the winding portion 22a provided at one end of the swing arm 22, and these A rubber 83 vulcanized and bonded to the inner cylinder 81 and the outer cylinder 82 is provided.

The second bushing 68 has the same structure as that of the first bushing 67 (reference numerals are separately provided for convenience), and the outer cylinder 82 is applied to the upper surface 22 b of the swing arm 22.
The third bush 69 includes an inner cylinder 85 fitted to the support shaft 66, and a rubber 86 vulcanized and bonded around the inner cylinder 85, and the rubber 86 is applied to the lower surface 22c of the swing arm 22. is there.
The first stopper 76 includes a stopper support member 76a extending downward from the main frame 21 and an arcuate stopper body 76b attached to the lower end of the stopper support member 76a.

  As described above, the vicinity of the pivot shaft 64 of the swing arm 22 is vertically sandwiched between the second bush 68 and the third bush 69 to limit the vertical swing of the swing arm 22 and in addition to the elastic force of the swing arm 22 itself. By the elastic force and damping force of the second bush 68 and the third bush 69, the impact and vibration transmitted from the rear wheels 24 and 26 (see FIG. 2, rear wheel 24 not shown) to the main frame 21 are absorbed.

  In (b), the first bush 67 vulcanizes and bonds rubber 83 between the inner cylinder 81 and the two outer cylinders 82, and the third bush 69 adds rubber 86 to two locations of the inner cylinder 85. The first bush 67 and the third bush 69 are disposed between the two pivot plates 61, 62, the shaft insertion holes 61a, 61b are opened in the pivot plate 61, and the shaft insertion holes are formed in the pivot plate 62. 62a and 62b are opened, the pivot shaft 64 as a bolt is passed through the shaft insertion hole 61a, the inner cylinder 81 and the shaft insertion hole 62a, and the first nut 88 is screwed into the male screw 64a provided at the tip of the pivot shaft 64. The pivot shaft 66, which is a bolt, is passed through the shaft insertion hole 61b, the inner cylinder 85, and the shaft insertion hole 62b, and a second nut 91 is screwed into a male screw 66a provided at the tip of the support shaft 66 to pivot. Attaching the first bushing 67 and third bushing 69 to 61 and 62. The second bush 68 (see (a)) is attached in the same manner as the first bush 67 and the third bush 69.

  4 is a cross-sectional view taken along line 4-4 of FIG. 1. A bearing member 94 is attached to the rear end of the swing arm 22, and the axle shaft 23 is rotatably passed through the bearing member 94 via bearings 95 and 96. A sprocket support flange 73 and a wheel 97 constituting the rear wheel 24 are spline-coupled to a male spline 23a provided at one end of the axle 23, and a disk support flange is connected to the male spline 23b provided at the other end of the axle 23. 98 and the wheel 101 constituting the rear wheel 26 are spline-coupled, nuts 102 and 103 are screwed to both ends of the axle 23, a driven sprocket 74 is attached to the sprocket support flange 73, and a screw 105 is attached to the disk support flange 98. The brake disc 56 is attached to the projecting portion 106 provided at one end of the bearing member 94 with bolts 107 and 10. In indicating that attaching the brake caliper 57. In addition, 108 ... are nuts screwed into bolts 78 ... for attaching the driven sprocket 74.

  The bearing member 94 is formed with annular convex portions 94a and 94b for winding the winding portion 22d of the swing arm 22, and by arranging the swing arm 22 between these annular convex portions 94a and 94b, The axial movement of the bearing member 94 with respect to the swing arm 22 is prevented. Reference numeral 111 denotes an anti-rotation portion formed integrally with the bearing member 94 in order to prevent the bearing member 94 from rotating with respect to the swing arm 22.

  As described above, the driven sprocket 74 is disposed in the vicinity of the inner side of the rear wheel 24, and the brake disk 56 and the brake caliper 57 are disposed in the vicinity of the inner side of the rear wheel 26. The caliper 57 is difficult to see from the side of the vehicle body, and the appearance can be improved.

  5 is a cross-sectional view taken along line 5-5 of FIG. 1. A fan 122 is attached to one end of a crankshaft 121 rotatably mounted in the engine 27 with a nut 123, and is integrally protruded laterally from the fan 122. The weights 124 are swingably attached to the shafts 122a, and the weights 124 are surrounded by the drum 126, so that the centrifugal clutch is removed from the shafts 122a, weights 124, and the drum 126. 127, a bearing portion 128 is disposed outside the crankcase 27a of the engine 27, and an output shaft 132 integrally formed with the drum 126 via the bearing 131 is rotatably attached to the bearing portion 128. The drive sprocket 72 is spline-coupled to the male spline 132 a provided on the shaft end on the outer side of the bearing portion 128. The shaft end receiving portion 134 supports the tip end portion of the output shaft 132 through a bearing 135, and the engine support member 71 is disposed below the engine 27. The engine support member 71 .., And a boss provided on the crankcase 27 a on the other end side of the crankshaft 121. Side support members 143 are attached to the portions 27b and 27b via spacers 141, 141, 142, and 142 with bolts 144, and the side support members 143 are also attached to the end portions of the side protrusions 71b of the engine support member 71. Is attached with bolts 146.

  Here, 151 is a bolt that prevents the weight 124 from coming out of the shaft portion 122a, 152 is a shoe provided at the end of the weight 124 so as to contact the inner peripheral surface of the drum 126, and 153 and 154 fix the bearing 131. 156, 157 are collars for positioning the drive sprocket 72 to the output shaft 132, 161, 162 constitute an engine support member 71 and upper and lower support members that sandwich the swing arm 22, 163 ... Are bolts that fasten the upper support member 161 and the lower support member 162 in order to sandwich the swing arm 22.

6 is a cross-sectional view taken along line 6-6 of FIG. 1, and shows a handle mounting structure of the vehicle 10 (see FIG. 1).
That is, the steering stem 13 is rotatably supported by an upper bearing 171 provided at the upper end of the head pipe 12 and a lower bearing 172 provided at the lower end of the head pipe 12 (see FIG. 1). A spacer 174 is positioned on the upper portion of the handle post 17, a handle support plate 176 is applied to the upper portion of the spacer 174, and a pair of handle bars 177 and 178 attached so as to penetrate through the handle support plate 176 are respectively spacers. 174 and the handle post 17 are passed through in this order, and a handle support plate 176 between the two handle bars 177 and 178 and a spacer 174 are passed through one handle mounting bolt 182 and mounted in the upper end of the steering stem 13. Tsu preparative member at 183 screwing the handle mounting bolts 182 to indicate that the attached handle 18 of the handle bar 177, 178 to the steering stem 13.
The handle support plate 176 and the handle bars 177 and 178 are members constituting the handle assembly 184.

  Here, reference numeral 186 denotes a lock nut for fixing the upper bearing 171 to the steering stem 13 side, reference numeral 187 denotes a hollow portion provided in the handle post 17 for inserting the steering stem 13, and reference numerals 188 and 191 denote the handle bars 177 and 178, respectively. Handle insertion holes provided in the handle post 17, 192 and 193 are handle through holes opened in the spacer 174 to penetrate the handle bars 177 and 178, and 194 and 196 are handles to penetrate the handle bars 177 and 178 Handle through hole opened in the support plate 176, 201 is a bolt insertion hole opened in the spacer 174 for passing the handle mounting bolt 182, 202 is a bolt insertion hole opened in the handle support plate 176 for passing the handle mounting bolt 182, 203 is handle removal A bolt 182 is a female thread formed on the nut member 183 to screw connection.

  7 is a cross-sectional view taken along the line 7-7 in FIG. 6. The concave portions 205 and 206 are formed on the lower surface of the spacer 174, the convex portions 207 and 208 are integrally formed on the upper end of the nut member 183, and the convex portions 205 and 206 are convex. It shows that the spacer 174 is positioned with respect to the nut member 183 by fitting the portions 207 and 208.

FIGS. 8A and 8B are perspective views showing a vehicle handle mounting structure according to the present invention. FIG. 8A is a perspective view of a spacer 174 and a handle assembly 184. FIG. 8B is a handle post 17 and a nut. 3 is a perspective view of a member 183. FIG.
In (a), the spacer 174 is a member in which concave portions 205 and 206 are formed on the lower surface 174a at a position sandwiching the bolt insertion hole 201 and before and after the bolt insertion hole 201.
In (b), it is shown that the nut member 183 is formed with convex portions 207 and 208 at the upper end so as to face each other so as to sandwich the female screw 203 therebetween.

  As shown in (a) and (b) above, the recesses 205 and 206 are formed in the spacer 174, and the protrusions 207 and 208 are formed in the nut member 183, so that the handle assembly 184 is attached to the handle post 17. When assembled, the spacer 174 can be easily positioned on the handle post 17. With the spacer 174 positioned on the handle post 17, the handle through holes 192 and 193 (see FIG. 6) of the spacer 174 and the handle post 17 The handle bars 177 and 178 of the handle assembly 184 can be easily passed through the handle insertion holes 188 and 191.

FIG. 9 is a cross-sectional view showing a vehicle engine according to the present invention.
The engine 27 includes an engine main body 261. The engine main body 261 includes a cylinder block 262 integrated with a cylinder head and a crankcase 27a joined to a lower end surface of the cylinder block 262.

The cylinder block 262 includes a single cylinder 266 that houses the piston 264 at the center.
The crankcase 27a is a member in which a pair of upper and lower case halves 263a and 263b are joined by a plurality of bolts. Is attached rotatably. A connecting rod 272 connects the piston 264 to the crankshaft 121, and a fuel tank 273 is attached to the lower portion of the crankcase 27a.

The crankcase 27 a includes a crank chamber 275 provided in the center, and an oil reservoir chamber 276 and a valve operating chamber 277 respectively disposed on the side of the crank chamber 275.
The crank chamber 275 is where the crank portion 271a of the crankshaft 121 is disposed.
The oil reservoir chamber 276 is a place where a predetermined amount of lubricating oil is stored, and houses an oil slinger 278 attached to the crankshaft 121 for stirring and scattering the lubricating oil (that is, generating oil mist).

  The oil slinger 278 includes a plurality of long arm blades 278a and a plurality of short arm blades 278b, and the long arm blades 278a and the short arm blades 278b are bent in directions opposite to each other in the axial direction of the crankshaft 121. .

  As described above, the oil reservoir chamber 276 provided with the oil slinger 278 is provided in the crankcase 27a, so that the lubricating oil in the oil reservoir chamber 276 is agitated by the rotation of the oil slinger 278 in any operating posture of the engine 27. Thus, oil mist can always be generated.

  The valve operating chamber 277 extends through one side of the cylinder block 262 to the head, and includes a valve operating device 281 that opens and closes the intake valve and the exhaust valve on the valve operating chamber 277. Reference numeral 282 denotes a head cover that covers the upper portion of the cylinder block 262, and reference numerals 283 and 284 denote rocker shafts and rocker arms that constitute the valve gear 281.

The crank chamber 275 and the oil reservoir chamber 276 are communicated with each other via a through hole 271b opened in the crankshaft 121.
Since the opening to the oil reservoir chamber 276 is disposed at the center of the oil reservoir chamber 276, the through hole 271b can store the lubricating oil in the oil reservoir chamber 276 in any inclined or inverted state of the engine 27. The opening is set so as not to sink.

The crankcase 27 a includes a valve chamber 286 that communicates with the valve operating chamber 277 and an oil return chamber 287 that surrounds the valve chamber 286.
The valve chamber 286 is a portion provided with a one-way valve 291 that communicates with the bottom of the crank chamber 275 via the valve hole 288 and opens and closes the valve hole 288.

The one-way valve 291 is a member that closes the valve hole 288 when the pressure is reduced and opens the valve hole 288 when the pressure is increased according to the pressure pulsation in the crank chamber 275.
The oil return chamber 50 communicates with the oil reservoir chamber 276 through the through hole 292, and also communicates with the valve operating chamber 277 through an orifice (not shown).
In the figure, 293 is a recoil starter, and 294 is an ignition coil.

Next, the operation of the engine 27 described above will be described.
While the engine 27 is in operation, when the oil slinger 278 stirs the lubricating oil in the oil reservoir chamber 276 by the rotation of the crankshaft 121 to generate oil mist, when the crank chamber 275 is depressurized by the upward movement of the piston 264, The oil mist is sucked into the crank chamber 275 through the through hole 271b and lubricates around the crank portion 271a and the piston 264.

  Further, when the crank chamber 275 is pressurized by the downward movement of the piston 264, the oil mist is blown from the valve hole 288 and the valve chamber 277 together with the blow-by gas generated in the crank chamber 275 by opening the one-way valve 291. The oil mist and blow-by gas are separated in the valve operating chamber 277, the oil mist lubricates each part of the valve operating device 281 and the blow-by gas is discharged to the air cleaner.

  Further, the oil mist sent to the valve operating chamber 277 returns to the oil reservoir chamber 276, and the lubricating oil liquefied in the valve operating chamber 277 returns to the oil return chamber 287 through an orifice (not shown). Then, the recirculation of the oil mist and the liquefied lubricating oil is performed without any problem even when the engine 27 is inclined. Further, even if the engine vibrates due to road surface unevenness during running, the oil mist and lubricating oil can be recirculated without any problem.

The operation when the swing arm 22 described above swings will be described below.
FIG. 10 is a first action diagram showing the action at the time of swing arm swing of the vehicle according to the present invention.
When the swing amount becomes large when the swing arm 22 swings upward with respect to the main frame 21, the upward movement of the swing arm 22 is stopped by the second stopper 77 provided at the rear end of the main frame 21, and the swing arm 22 Prevent excessive swinging.

FIG. 11 is a second operation diagram showing the operation of the vehicle according to the present invention during a swing arm swing, and the operation of the bush and the stopper will be described.
When the swing arm 22 swings upward, the outer cylinder 82 of the second bush 68 is pushed up by the swing arm 22 and moves upward, so that the rubber 83 of the second bush 68 is deformed to generate elastic force and damping force. . When the upward swing amount of the swing arm 22 is large, the outer cylinder 82 moves upward largely against the elastic force of the rubber 83, and the outer cylinder 82 hits the stopper main body 76 b of the first stopper 76. Therefore, excessive deformation of the second bushing 68, specifically the rubber 83, can be prevented by the first stopper 76, so that the rubber 83 is difficult to sag and the life of the second bushing 68 can be extended.

  As described above with reference to FIGS. 1 and 2, the present invention firstly attaches a front fork 14 to the head pipe 12 so as to be steerable, and attaches a front wheel 16 to the lower end of the front fork 14. In the vehicle 10 in which the main frame 21 as a book frame extends rearward, the main frame 21 has a shape in which an S-shape is laid sideways in the vehicle front-rear direction in a side view, and a lower portion provided in the front half of the S-shape. A bottom part 36a as a leg straddle part and floor support parts 44 and 45 as footrest parts are provided in a convex front arc part 36, and a space below the convex rear arc part 38 provided in the latter half part of the S-shape. The engine 27 is arranged in the above.

  Since the main frame 21 is a single S-shaped frame, the main frame 21 can be smoothly bent into an arc shape and the number of bent portions can be reduced, and the workability of the main frame 21 can be improved. Therefore, the cost of the main frame 21 can be reduced.

  Further, if the whole or a part of one S-shaped main frame 21 is exposed to the outside, a slim and flowing appearance can be obtained, and a good impression can be given to the viewer. Can be improved. Therefore, the merchantability of the vehicle 10 can be improved.

  Furthermore, the bottom 36a that is the leg straddle part and the floor support parts 44 and 45 that are the footrest parts are formed using the S-shaped front arc part 36, and the space below the S-shaped rear arc part 38 is used. Since the engine arrangement space is formed, the vehicle 10 can be simplified and the space can be effectively used.

Second, the present invention is characterized in that the engine 27 is attached to a swing arm 22 extending rearward from a substantially middle portion of the S shape of the main frame 21.
In the space below the rear arc portion 38, the space for moving the engine 27 up and down when the swing arm 22 swings can be secured together with the engine placement space. Thereby, the space of the vehicle 10 can be used effectively, and the vehicle 10 can be reduced in size and size.

Thirdly, the present invention is characterized in that the front arc portion 36 and the rear arc portion 38 have the same radius of curvature.
By making the curvature radius of the front arc portion 36 and the rear arc portion 38 the same, the workability of the S-shaped main frame 21 can be further improved, and the productivity of the S-shaped main frame 21 can be increased. it can. Therefore, the cost of the main frame 21 can be reduced.

Fourth, the present invention is characterized in that the main frame 21 is a square pipe.
Since the main frame 21 is made of a square pipe, for example, the strength and rigidity can be increased compared to a frame made of a round pipe. In addition, since the main frame 21 is a square pipe, it becomes easy to weld a bracket to the main frame 21 or to directly attach a part with a screw or the like, so that the productivity of the vehicle 10 can be improved. The cost of the vehicle 10 can be reduced.

Fifth, the present invention is characterized in that a second stopper 77 with which the swing arm 22 abuts is provided at the rear end of the S-shape of the main frame 21.
Since it is the rear end of the S-shape of the main frame 21, the second stopper 77 can be easily provided and the second stopper 77 abuts against the rear portion of the swing arm 22. For example, the stopper is in front of the swing arm. In the present invention, the swing of the swing arm 22 can be reliably stopped as compared with the contact with the portion.

  In the present embodiment, as shown in FIG. 1, the main frame 21 is composed of a front straight part 35, a front arc part 36, a central straight part 37, and a rear arc part 38. Not only this but you may comprise only the front straight part 35 and the rear circular arc part 38. FIG.

  The vehicle frame of the present invention is suitable for a two-wheeled vehicle.

1 is a side view of a vehicle according to the present invention. 1 is a rear side view of a vehicle according to the present invention. It is sectional drawing which shows the swing arm attaching part of the vehicle which concerns on this invention. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6. 1 is a perspective view showing a vehicle handle mounting structure according to the present invention. It is sectional drawing which shows the engine of the vehicle which concerns on this invention. FIG. 6 is a first operation diagram showing an operation at the time of swing arm swing of the vehicle according to the present invention. It is a 2nd operation | movement figure which shows the effect | action at the time of the swing arm swing of the vehicle which concerns on this invention. It is a side view of the vehicle provided with the conventional frame.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 12 ... Head pipe, 14 ... Front fork, 16 ... Front wheel, 21 ... Frame (main frame), 22 ... Swing arm, 27 ... Engine, 36 ... Front arc part, 36a ... Leg straddle part (bottom part) , 38 ... rear arc part, 44, 45 ... foot rest part (floor support part), 77 ... stopper (second stopper).

Claims (5)

In a vehicle in which a front fork is attached to a head pipe so as to be steerable, a front wheel is attached to a lower end of the front fork, and one frame extends backward from the head pipe.
The frame has a shape in which the S-shape is laid sideways in the vehicle front-rear direction in a side view, and a leg straddle portion and a footrest portion are provided in a front convex arc portion provided in the front half of the S-shape, A vehicle frame, characterized in that an engine is arranged in a space below an upward convex rear circular arc portion provided in the second half of the S-shape.   The vehicle frame according to claim 1, wherein the engine is attached to a swing arm extending rearward from a substantially middle portion of the S-shape of the frame.   The vehicle frame according to claim 1 or 2, wherein the front arc portion and the rear arc portion have the same radius of curvature.   The vehicle frame according to claim 1, wherein the frame is a square pipe.   The vehicle frame according to claim 2, wherein a stopper with which the swing arm abuts is provided at a rear end of the S-shape of the frame.

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