JPH05185977A - Motorcycle - Google Patents

Abstract

PURPOSE:To reduce transmission of vibration and heat of a V-engine of a motorcycle to a vehicle body frame of the motorcycle. CONSTITUTION:A pair of right and left engine support frames 23 are fixed to the intermediate part of a vehicle body frame having a rear bracket 5, which has a steering shaft cylinder 2 on the front end, and by which a rear arm 16 is supported on the rear end, and each of the engine support frame 23 is put in line when seen from the side. The support frame is extended down to a vertical direction in right angle when seen from the front surface, and the rear part of an engine 25 is mounted on the rear bracket 5, while the proximities of a V-type valley between an upper cylinder 26 and a lower cylinder 27 are mounted on the engine support frame 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body frame of a motorcycle with a V-type engine, which can reduce vibrations and heat of the engine to the vehicle body frame and eventually to the driver. Is.

[0002]

2. Description of the Related Art A motorcycle in which a cylinder head and a crankcase of a V-type engine can be easily and easily attached to and removed from a vehicle body frame has been conventionally known (Japanese Utility Model Publication No. 38-3806). In order to easily and easily attach or detach the V-type engine to the conventional vehicle body frame, it is most convenient to arrange the cylinders in a horizontal V-shape vertically with a side view. In such an arrangement, in the conventional body frame, the cylinder head and the crankcase cannot be attached to the body frame because of the relative relationship between the structure of the body frame and the size of the engine. The outline of the structure of the vehicle body frame and the mechanism for attaching the V-type engine to the vehicle body frame in this prior art is as follows. That is, a pair of left and right V-shaped main frame bodies 1 (see the above publication, the same applies to the following in this section) are laterally connected by a fulcrum 7,
Head pipe 3 (steering shaft tube that supports the steering shaft)
Of the central vertical rod 5 fixed to the lower end of the head pipe 3 and the upper end of the head pipe 3 to the fulcrum 7, and further to the upper end of the head pipe 3 a pair of left and right engine supports 9 extending diagonally downward. Is fixed to the front portion of the V-shaped main frame body 1, and the U-shaped frame rod 4 is attached to the bent portion of the V-shaped main frame body 1.
The front end of the V-shaped engine 15 is attached to the lower end of the V-shaped main frame 1 and the supporting plate 17 provided at the bottom of the V-shaped main frame 1 to attach the crankcase 18 of the V-type engine 15 to the upper and lower cylinders. The cylinder head cover is attached to a bracket 16 protruding downward from the lower end of the engine support rod 9 and the vertical rod of the V-shaped main frame 1. However, the cylinder head cover of the engine is fixed to the cylinder block with bolts through the cylinder gasket, and the cylinder head cover is the hottest part because it is heated by the combustion gas in the cylinder. Since it is supported by the vehicle body frame in a so-called suspended state via a rod, there are the following problems, and this tendency becomes greater as the engine output increases, in particular. That is, the heat transfer from the engine to the vehicle body frame is large, and this is transmitted to the passengers via the vehicle body frame, the fuel tank, etc., and the vibration of the engine body frame is large due to the unstable support of the engine. The vibrations are transmitted to the vehicle body, which not only impairs the riding comfort of passengers but also increases fatigue. Furthermore, a large force is applied to the tightening bolt of the cylinder head cover due to the vibration of the engine body frame,
Since this force overlaps with the explosive force in the combustion chamber, an excessive repetitive load is applied to the tightening bolt of the cylinder head cover. Therefore, in some cases, the rigidity and strength of the tightening bolts for the cylinder head cover of the V-type engine in the above-described conventional technique may need to be strengthened as compared with a normal V-type engine. In addition to increasing the strength, the rigidity and strength of the cylinder block will be greatly affected.

[0003]

SUMMARY OF THE INVENTION The present invention has as its object to solve the above-mentioned problems of the prior art. To this end, by devising the structure of the vehicle body frame, the crankcase of the engine or its vicinity is provided with a structural material of the vehicle body frame. The task is to be able to attach to.

[0004]

[Means for Solving the Problems] Means for solving the above-mentioned problems include a rear bracket having a steering shaft tube for supporting a steering shaft at a front end and a rear arm pivotally supported at a rear end. It is configured by the following elements (a) to (c) assuming a motorcycle in which a side view V-type engine having an upper cylinder and a lower cylinder is attached to a body frame of the motorcycle. (A) A pair of left and right engine support frames are fixedly provided at an intermediate portion of the body frame, and (b) each of the pair of engine support frames is made substantially linear in a side view and is substantially vertical in a front view. (C) The rear part of the engine is attached to the rear bracket, and the vicinity of the V-shaped valley between the upper cylinder and the lower cylinder is attached to the engine support frame.

[0005]

[Operation] A pair of left and right engine support frames are fixed to the middle part of the body frame substantially vertically in side view and front view to form a structural material of the body frame, and further fixed to the rear end of the body frame. With the rear bracket that constitutes a part of the structural material of the body frame as the engine support part,
Since the vicinity of the V-shaped valley portion between the upper and lower cylinders is attached to the engine support frame, the engine is directly supported by the rear portion, that is, the rear portion of the crankcase, on the structural portion of the vehicle body frame, and the V-shaped valley portion, that is, the crankcase. The portion very close to the front part of is supported by the engine support frame. Since the engine support frame is provided perpendicularly to the middle part of the body frame, it can have sufficient rigidity and strength. Since this also functions as a reinforcing member for the body frame, the rigidity of the body frame , Will increase the strength. Further, the engine is mounted on the engine support frame near the V-shaped valley in the front part of the crankcase. The vicinity of the V-shaped valley is extremely close to the front part of the crankcase where the temperature is low and is higher than the upper part of the cylinder block. Even so, the temperature of the portion is closer to the crankcase than the lower end of the cylinder block, which is relatively low in temperature, and therefore the temperature of this portion is extremely lower than that of the cylinder head cover. Further, since the vibration near the crankcase is weak and the amplitude is small, the vibration transmitted from the engine to the body frame is small. Furthermore, this V-shaped valley is located approximately in the middle of the left and right cylinder blocks, and is in a neutral position with respect to alternate impacts due to explosions in the upper and lower cylinder combustion chambers, so it is also possible to deal with direct impacts associated with the explosions. The engine can be supported stably. Therefore, the transmission of heat and vibration of the engine to the vehicle body frame is significantly alleviated.

[0006]

[Examples] Next, examples will be described in detail with reference to the drawings. Reference numeral 1 denotes a motorcycle frame, which includes a pair of left and right main pillars 3 extending from the steering shaft tube 2 rearward and obliquely downward in a substantially straight line, and a pair of left and right descending columns which extend downward and are bent rearward therefrom. With tube 4. Main pillar 3 and descending pipe 4
Is a cylinder with a square cross section and is drawn from an aluminum alloy. The rear end has a thickness of about 1
They are connected to each other by a bracket 5 made of a 0 mm aluminum plate. Reference numeral 6 is a reinforcing stay for supporting the main pillar, 7 is a supporting frame for the occupant's seat 8, and 9 is its supporting pillar. In addition, 11 is a front fork supported by the steering shaft tube 2 so as to be freely turnable, and 12 is a front wheel supported at its lower end. Further, 13 is a front cover of the vehicle body frame, and 14 is a fuel tank. A rear portion of the engine 25 is attached to the bracket 5 by a bolt, and a rear arm 16 is supported by a shaft 15 so as to be vertically swingable. 17 is a rear wheel. The rear arm 16 has a chevron-shaped reinforcing member 1 at the top.
8 is integrally formed, and the reinforcing member 18 is connected via a rod 19 and a link 21 to a coil spring-equipped shock absorber 22 mounted in the left-right direction of the vehicle body. The pair of left and right main columns 3 hangs the engine support frame 23 downward from each of the intermediate portions from the steering shaft tube 2 to the bracket 5. The engine support frame 23 is connected immediately after the descending pipe 4 and its bent portion 4 a, and has an upper cylinder 26 and a lower cylinder 27 between the engine support frame 23.
The engine 25 is mounted, and the middle of the engine is mounted between these support frames.
An exhaust pipe connected to each of the cylinders, and a vaporizer 31. The left and right engine support frames 23 have a sufficient space between them to mount the engine, and as shown in FIG. 2, the outer plate 2 erected by butt welding between the main column 3 and the descending pipe 4.
3a and the inner plate 23b, both plates 23a, 23
b is bent from the front and rear edges and abutted against each other and welded at the W portion to form a box shape. 32 is an outer plate 23a and an inner plate 2
It is attached to the side surface of the engine 25 by a bolt 34 through a rubber damper 33 by a cylindrical boss bridged and welded to the 3b. The rear end of the crankcase of the V-type engine 25 is attached to the rear end of the main pillar 3 and the rear end of the descending pipe 4 by the mounting bolts 5a and 5b at the substantially middle portion and the lower end of the bracket 5, and the upper cylinder 26 and The vicinity of the valley between the lower cylinder 27 and the lower end of the upper cylinder block in this example is attached to the lower portion of the engine support frame 23 by the attachment bolts 23c. By constructing the vehicle body frame as described above, the rear end of the crankcase of the horizontal V-type engine and the upper and lower cylinders 26 and 27
The vicinity of the V-shaped valley portion between and can be directly attached to the engine support frame, and the vicinity of the V-shaped valley portion can be attached to the engine support frame forming a part of the structural material of the vehicle body frame. Since the temperature around the V-shaped valley is relatively low, the vibration is weak, and the amplitude of the vibration is relatively small, the heat and vibration of the engine to the vehicle body frame can be remarkably reduced.

[0007]

[Effect] The above-mentioned object of the present invention is novel. Therefore, it is an effect peculiar to the present invention that the above-mentioned new problems are solved and the above-mentioned conventional problems are sufficiently solved.

It is as described in the section of [Operation].

[Brief description of drawings]

FIG. 1 is a side view showing a frame structure of a motorcycle according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a perspective view of a frame of the motorcycle of the present invention.

[Explanation of symbols]

 1 ... Frame 2 ... Steering shaft tube 3 ... Main pillar 5 ... Bracket 16 ... Rear arm 23 ... Engine support frame 25 ... Engine

Claims (1)

[Claims] 1. A steering shaft tube for supporting a steering shaft at a front end,
In a motorcycle in which a V-type engine having an upper cylinder and a lower cylinder is attached to a vehicle body frame having a rear bracket on which a rear arm is pivotally supported at a rear end, a pair of left and right engine support frames are provided in an intermediate portion of the vehicle body frame. The pair of engine support frames are fixedly provided, and each of the pair of engine support frames has a substantially linear shape in a side view, and is a support frame that hangs in a substantially vertical direction in a front view. The rear part of the engine is attached to the rear bracket, and the upper cylinder and the lower part A motorcycle characterized in that the vicinity of a V-shaped valley between the cylinder and the cylinder is attached to the engine support frame.