JPS647918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a device for vibration-proofing and supporting an engine in, for example, a chain-driven two-wheeled motor vehicle.

In chain-driven motorcycles, the chain is strongly stretched, especially during sudden acceleration or deceleration, and this tension is transmitted to the engine. Therefore, the engine is usually fixed directly to the frame, that is, rigidly mounted, and the engine is stretched as the chain tension fluctuates. It is designed to prevent vibration. However, this type of mounting structure has the problem that engine vibrations are directly transmitted to the frame, so conventionally the engine was rubber mounted to the frame via anti-vibration rubber to cut off the transmission of engine vibrations. be. In this case, if the spring constant of the rubber mount and its mounting position are set with only vibration-proofing performance in mind, the engine will be strongly pulled in the direction of tension by the tension of the chain, reducing the distance between the front and rear sprockets. As a result, the chain may slacken significantly, causing the sprocket and chain to strike against each other, causing unpleasant hitting sounds, or causing both to wear out. Therefore, in the past, the engine could only be mounted with rubber to the extent that the chain did not slacken significantly, and there was a limit to the measures taken to absorb engine vibrations.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a vehicle engine support device that can regulate the displacement of the engine without reducing the vibration isolation performance of the frame.

That is, in order to achieve the above object, the present invention
Supports the engine crankcase on the frame,
Assuming that the vehicle is such that the power of the engine is transmitted to the drive wheels via a wrap-around transmission body that spans between one rear side of the crankcase and the drive wheels, the front end of the above-mentioned crankcase on the cylinder side is anti-vibration supported on the frame via anti-vibration rubber, and the rear end of the crankcase on the transmission body side is swingably supported on the frame via a pivot shaft and a bearing. .

The present invention will be explained below based on an embodiment shown in the drawings.

In the figure, reference numeral 1 denotes a head pipe, and a main pipe 2 extending rearward and a pair of left and right down tubes 3, 3 extending downward are welded to the rear surface. A front fork 4 is pivotally supported on the head pipe 1, and this front fork 4 pivotally supports a front wheel 5 as a steering wheel. main pipe 2
The front ends of a pair of left and right seat pillar tubes 6, 6 are welded to both sides of the rear end, and the rear ends of these seat pillar tubes 6, 6 are curved forward to form the down tube. It is connected to 3,3. Further, the front ends of a pair of left and right seat rails 7, 7 are welded to the front ends of the seat pillar tubes 6, 6, and the rear lower surfaces of the seat rails 7, 7 and the lower ends of the seat pillar tubes 6, 6 are welded to the front ends of the seat pillar tubes 6, 6. Backstays 8, 8 are installed between the rear surface and a double cradle-shaped frame 9. Further, a rear arm 11 having a generally triangular side frame is pivotally supported between rear arm brackets 10, 10 welded to the front surfaces of the lower ends of the seat pillar tubes 6, 6. This rear arm 11 is suspended by one shock absorber 13, and a rear wheel 14 serving as a driving wheel is pivotally supported at the rear end of this rear arm 11.

Incidentally, an engine 15 is mounted on the frame 9. The engine 15 in this embodiment is a water-cooled two-stroke single-cylinder engine, and includes a cylinder 17 on the upper surface of the front end of a crankcase 16. Therefore, this engine 15
The cylinder axis extends substantially in the vertical direction, and the inertia force due to the vertical movement of a piston (not shown) acts on the crankcase 16 substantially in the vertical direction. A drive sprocket 19 is fixed to one end of an output shaft 18 disposed on the rear side of the crankcase 16, and the drive sprocket 19 is located on one side of the crankcase 16. Between the drive sprocket 19 and the driven sprocket 20 fixed to the rear wheel 14, a chain 21 as a winding power transmission body is spanned, and the rear wheel 14 is driven via this chain 21. Ru.

The crankcase 16 of the engine 15 has a left-right split structure, with a pair of left and right case halves 22 and 23 abutting each other, and the front end on the cylinder 17 side and the drive sprocket 19 side. The rear end portions are respectively down tubes 3, 3,
It is mounted on the seat pillar tubes 6,6. First, to explain the mounting structure at the front end, engine brackets 24, 24 are welded to the lower rear surfaces of the down tubes 3, 3, facing each other.
A bolt 25 is installed between them and tightened with a nut 26. Further, the front end portions of the case structure halves 23, 23 are formed with bulges 28, 28 which constitute the front end support protrusion 27 in the state where they abut, that is, at the front end portion of the crankcase 16. This front end support protrusion 27 is interposed between the engine brackets 24, 24. The bolt 25 passes through mounting holes 29, 29 formed in the front end support protrusion 27, that is, the bulges 28, 28. Structure 30,
30 is press-fitted. Anti-vibration rubber structure 30, 30
is a rubber damper 3 having a cylindrical shape around the outer circumference of the inner cylinder 31.
2 is baked and fixed, and this rubber damper 3
An outer cylinder 33 is similarly baked and fixed around the outer periphery of the mounting holes 29, and is press-fitted from the left and right sides of the mounting holes 29, 29, respectively. In this press-fitting state, one end portions of the inner cylinders 31, 31 are abutted against each other. Therefore, the front end of the crankcase 16 can be attached to the engine brackets 24, 24 by inserting the bolt 25 into the inner cylinders 31, 31 and tightening the insertion end of the bolt 25 with the nut 26.
It is designed to be rubber mounted in between. Note that there are predetermined gaps 34a, 34b between both end surfaces of the front end support protrusion 27 and the inner surfaces of the engine brackets 24, 24 facing thereto. In the gap 34a on the side where
A damper spacer 35 made of synthetic resin is interposed. This damper spacer 35 is connected to the vibration isolating rubber structure 3
It is coaxially attached to the outer peripheral surface of the inner cylinder 31 of 0.

On the other hand, a cross pipe 36 is installed between the lower portions of the seat pillar tubes 6, 6. A pair of engine brackets 37, 37 are welded to the front part of the cross pipe 36 at a distance from each other in the left and right direction.
A pivot shaft 38 is installed between 7 and 7, and a nut 39
It is tightened by. Further, bulging protrusions 41, 41 are formed at the rear end portions of the case structure half pieces 22, 23 to form a rear end support protrusion 40 at the rear end portion of the crankcase 16. The support protrusion 40 is attached to the engine brackets 37, 37.
It has come to be located in between. The rear end support projection 40, that is, the bulging projections 41, 41, are provided with through holes 42, 42 located at or near the instantaneous center of the engine 15, and the insides of these through holes 42, 42 are opened as described above. A pivot shaft 38 passes through it. A pair of left and right collars 43, 43 are fitted into the outer peripheral surface of the penetrating portion of the pivot shaft 38, and one end surface of these collars 43, 43 is abutted against each other, and the flange portion of the other end 4
4 and 44 are respectively held between both side surfaces of the rear end support protrusion 40 and the inner surfaces of the engine brackets 37 and 37 facing thereto. Therefore, the rear end support protrusion 40 is interposed between the brackets 37, 37 in a state where movement of the pivot shaft 38 in the axial direction is prevented. Moreover, such colors 43, 43 are
It is rotatably supported by ball bearings 45, 45 attached to the inner peripheral surfaces of the open ends of the through holes 42, 42. These ball bearings 4
5, 45, the inner ring 46 is connected to each collar 43, 43.
The outer rings 47 are press-fitted into the inner circumferential surfaces of the through holes 42, 42, and the inner rings 46, 46 are fitted with the outer circumferential surfaces of the collars 43, 43. 48 forcibly biases both sides of the pivot shaft 38 along the axial direction. Therefore, the rear end support protrusion 40 of the crankcase 16 is pivotally supported with respect to the engine brackets 37, 37 at or near the instantaneous center of the engine 15, and this crankcase 16 The rocking direction of the piston is substantially the same as the vertical movement direction of the piston. Rear end abutting walls 41a, 41a that abut each other are abutted on the rear end portions of the bulging protrusions 41, 41, and these abutting walls 41a, 41a allow the rear end supporting protrusion 40 to This is a sealed space in which the inside is separated from the outside to prevent foreign matter such as dust from adhering to the ball bearings 45, 45.

Note that 49 is a radiator and 50 is a carburetor.

According to such a configuration, the crankcase 16
The rear end of the drive sprocket 19 side is pivotally supported on the frame 9 at or near the instantaneous center of the engine 15, so that when inertia force due to the vertical movement of the piston acts on the crankcase 16, , this crankcase 16 swings up and down using the rear end support protrusion 40 as a fulcrum. On the other hand, the front end of the crankcase 16 on the cylinder 17 side is supported by a rubber mount, that is, anti-vibration, on the frame 9 via the anti-vibration rubber structure 30.
The swing of the crankcase 16 is controlled by the rubber damper 3.
2 and 32, and is transmitted to the frame 9 in an attenuated state. Therefore,
According to such a mount structure, it is possible to effectively block transmission of engine vibration to the frame 9, which not only improves riding comfort but is also advantageous in terms of strength.

Furthermore, according to this mount structure, the rear end of the crankcase 16 near the drive sprocket 19 only swings in the direction around the port shaft 38, so when sudden acceleration or sudden engine braking is applied, Even if the chain 21 is strongly stretched, there is no possibility that the rear end of the crankcase 16 will be twisted horizontally within the plane along the direction in which the chain 21 is stretched. As a result, chain 21
The amount of displacement of the engine 15 along the tensioning direction can be suppressed to a smaller range than that of conventional rubber mount structures, and the occurrence of hammering noise due to loosening of the chain 21 and the chain 21, drive, driven sprocket 19, 20 wear etc. can be prevented. Therefore, this mount structure can reliably restrict torsional displacement of the engine 15 while effectively blocking engine vibrations from the frame 9.

Furthermore, a certain clearance, that is, a gap 34, is provided between the front end support protrusion 27 of the crankcase 16 and the engine brackets 24, 24 during assembly.
a, 34b exist, among which chain 21
Since a damper spacer 35 is interposed in the gap 34a on the side where the engine 15 is about to be displaced by the tension of Therefore, even if the engine bracket 24 is displaced horizontally, one side of the front end support projection 27 can be prevented from colliding with the engine bracket 24. Therefore, there is an advantage in that it is possible to prevent the wear of these components and the generation of unpleasant hitting sounds.

Furthermore, in this embodiment, the inner rings 46, 46 are forcibly urged on both sides along the axial direction of the pivot shaft 38, thereby absorbing the rattling between the outer rings 47, 47 and the inner rings 46, 46, that is, the so-called axial clearance. This makes it possible to prevent the rear end support protrusion 40 of the crankcase 16 from swinging in the axial direction of the pivot shaft 38, thereby ensuring reliable mounting.

In the above embodiment, the pivot shaft is supported by a ball bearing, but it can be similarly implemented by using a roller bearing.

Further, it goes without saying that the engine support device according to the present invention is not limited to use in two-wheeled motor vehicles, but can also be applied to, for example, four-wheeled vehicles such as three-wheeled motor vehicles and carts.

According to the present invention described in detail above, when the engine vibrates due to the reciprocating motion of the piston, the engine oscillates using the rear end of the crankcase as a pivot point, and the engine oscillates at the front end of the crankcase. Since the engine vibration is absorbed by the vibration isolating rubber and transmitted to the frame in a damped state, transmission of engine vibration to the frame can be effectively blocked. Moreover, since the rear end of the crankcase only swings in the direction around the pivot shaft, even if the wrapped transmission body is strongly stretched, such as when sudden acceleration or engine braking is applied, There is no risk that the rear end of the crankcase will be twisted within a plane along the tensioning direction of the wrapped transmission body.

Therefore, the amount of displacement of the engine can be suppressed within a smaller allowable range than in the past, and it is possible to prevent loosening of the wrapped transmission body and occurrence of hammering noise. Therefore, while effectively blocking vibrations of the engine relative to the frame, it is possible to reliably prevent torsional displacement of the engine due to the tension of the wrapped conductor.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a side view of a two-wheeled motor vehicle, FIG. 2 is a side view of an engine portion, and FIG. 3 is a sectional view taken along the line - in FIG. 9...Frame, 14...Drive wheel (rear wheel), 1
5...Engine, 16...Crankcase, 17
... Cylinder, 21 ... Winding transmission body (chain), 27 ... Front end (front end support projection), 32 ...
Anti-vibration rubber (rubber damper), 38... Pivot shaft,
40... Rear end portion (rear end support protrusion), 45... Bearing (ball bearing).

Claims (1)

[Claims] 1. A crankcase of an engine is supported on a frame, and power from the engine is transmitted to the drive wheels via a wrap-around transmission body that spans between one rear side of the crankcase and the drive wheels. In a vehicle, the front end of the crankcase on the cylinder side is vibration-proofly supported on the frame via anti-vibration rubber, and the rear end of the crankcase on the winding transmission side is attached to the frame via a pivot shaft and a bearing. A vehicle engine support device characterized by being pivotably supported.