JP2002087367A - Engine mount structure for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure attaching rigidity without bringing problems such as weight increase of an engine and lowering of a degree of freedom on frame design, and without bringing a problem of increase in an engine width dimension and an influence to traveling performance. SOLUTION: In this engine mount structure wherein the engine 1 having a chain arranging chamber 33 surrounded by an inner wall 34 and an outer wall 35 in a width-directional side part is mounted between left and right side frame parts 2a, 2b extended along a body-longitudinal direction of a body frame 2, a mount bolt 41 comprising the first and second bolts 42, 43 is fitted in the side frame part 2b, the mount bolt 41 is inserted penetratedly through an insertion hole 35a formed in the outer wall 35 to be screwed in to the inner wall 34, and the engine 1 is thereby fixed to the side frame 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic so-called side chain type engine having a chain arrangement chamber at a side portion in a vehicle width direction, which is mounted between left and right side frame portions of a body frame extending in a vehicle front-rear direction. The present invention relates to an engine mount structure for a motorcycle.

[0002]

2. Description of the Related Art When an engine is mounted on a body frame of a motorcycle, it is desirable that the rigidity of mounting the engine to the body frame be increased and that the rigidity of the engine itself contribute to the improvement of the rigidity of the entire body frame.

Conventionally, when the above-mentioned side chain type engine is mounted on a vehicle body frame, as shown in FIG. 6, for example, as shown in FIG. 6, a mount boss portion 51 is provided on a front wall 50a or a rear wall 50b of a rigid rigid head 50. In some cases, the mounting boss portion 51 is mounted on the vehicle body frame 53 via a bracket 53a or the like.

[0004]

However, in the case where the above-described conventional structure in which the mount boss 51 is overhanged is adopted, the mount boss 5 is overhanged.
There is a concern that the rigidity of No. 1 and eventually the mounting rigidity will decrease. To avoid this problem, mount boss 51
It is necessary to enhance the rigidity of the mount boss itself by reinforcing the bosses with ribs 51a or the like, or to increase the thickness of the boss 51, and also to increase the rigidity of the bracket 53a.

[0005] However, adding the ribs or increasing the thickness of the ribs causes a problem that the weight of the engine and the frame increases. Also, the mounting location of the mount boss is limited due to the relationship between the intake system and the exhaust system, and in some cases, it is necessary to design the body frame in accordance with the mounting position of the mount boss. The degree may decrease.

Here, for example, as shown in FIG. 5, a boss portion 62a is integrally formed on an outer wall 62 constituting a chain arrangement chamber 61 of the engine 60, and the boss portion 62a is fastened to a vehicle body frame 63 by bolts 64. It can be fixed.

In this case, interference with the intake and exhaust systems of the mount boss can be avoided, and the degree of freedom in frame design can be increased. However, since the rigidity of the outer wall 62 itself of the chain arrangement chamber 61 is low, in order to secure necessary mounting rigidity, the boss 62a is enlarged to increase the rigidity near the boss 62a, and the bolt 6
In order to secure the tightening allowance a of 4, the boss portion 62a is largely projected outward from the outer wall 62a. If the boss portion 62a is projected inside the chain arrangement chamber 61, it becomes impossible to secure a space for passing the timing chain 65 at the time of assembling the engine.

However, when the boss portion 62a is formed to protrude outward, the vehicle width of the entire engine is increased by that amount, and the vehicle width of the body frame 63 may be increased accordingly. is there. The boss 62
There is a concern that the offset amount between the engine center and the frame center in the vehicle width direction is increased by the amount of outward projection of a, which affects running performance, particularly cornering characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and does not cause a problem of an increase in the weight of an engine or a decrease in the degree of freedom in designing a frame. It is an object of the present invention to provide a motorcycle engine mount structure that can secure the mounting rigidity without causing the influence of the above.

[0010]

According to a first aspect of the present invention, there is provided an engine having a chain arrangement chamber surrounded by an inner wall and an outer wall on a side portion in a vehicle width direction. In a motorcycle engine mount structure mounted between frame portions, a mount bolt is mounted on the side frame portion, and the mount bolt is screwed into the inner wall by passing through an insertion hole formed in the outer wall. Thus, the engine is fixed to the side frame portion.

According to a second aspect of the present invention, in the first aspect, the mount bolt includes a first bolt having a screw hole formed in an axis and a flange formed in an outer end portion, A second bolt screwed into the screw hole, wherein the first bolt is screwed and fixed to the inner wall in a state where the flange portion is in contact with the outer end surface of the insertion hole in the outer wall;
The second bolt is screwed to the first bolt to hold and fix the side frame portion with the first bolt.

According to a third aspect of the present invention, in the first or second aspect, the mount bolt is disposed so as to be located in a portion surrounded by a timing chain of the cylinder head.

[0013]

According to the engine mount structure of the present invention, the engine is mounted on the side frame by inserting the mount bolt mounted on the side frame into the outer wall of the chain arrangement chamber and screwing it to the inner wall. Since the engine is fixed to the frame portion, the inner wall of the engine having high rigidity is directly fastened to the side frame portion by the mount bolt, so that the mounting rigidity of the engine to the vehicle body frame can be secured.

Further, in the present invention, the tightening allowance of the mount bolt is set on the inner side wall of the engine, so that the fastening force can be secured without increasing the vehicle width dimension of the engine, and the boss portion is moved outward from the outer side wall. The vehicle width dimension of the engine can be reduced as compared with a case where the vehicle body is protruded, and an increase in the size of the body frame can be prevented. In addition, the offset amount between the engine center and the shiram center in the vehicle width direction can be reduced, and the influence on the running performance such as cornering characteristics can be prevented.

Further, in the present invention, since the side of the engine in the chain arrangement chamber, that is, the side wall in the vehicle width direction is fixed to the vehicle body frame, the mount boss portion is formed by overhanging the front and rear walls of the cylinder head. It is possible to avoid problems such as a decrease in mounting rigidity and an increase in engine weight, as well as to avoid interference with the intake and exhaust systems, thereby increasing the degree of freedom in frame design.

Further, at the time of assembling the engine, the mounting bolt is first passed through the timing chain, and then the mounting bolt is screwed on, so that the mounting bolt does not hinder the assembling of the timing chain.

According to the second aspect of the present invention, the side frame portion is sandwiched by screwing the second bolt to the first bolt fastened and fixed to the inner wall of the engine. The mounting rigidity when mounting on a vehicle can be increased.

According to the third aspect of the present invention, since the mount bolt is disposed in a portion surrounded by the timing chain of the cylinder head, it is easy to secure a tightening allowance and mounting rigidity of the mount bolt, and it is also possible to mount the mount bolt on a timing chain, a sprocket and the like. The mounting bolts can be arranged without interference.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 are views for explaining an engine mounting structure of a motorcycle according to an embodiment of the present invention. FIG. 1 is a left side view of the engine, and FIG. FIG. 3 is a right side view of the engine provided with the timing chain, and FIG. 4 is a sectional rear view of the engine mount. Note that the terms front, rear, left and right in the present embodiment refer to front, rear, left and right when viewed in a state of sitting on a seat.

In FIG. 1, reference numeral 1 denotes an engine suspended from a vehicle body frame 2 of a motorcycle. The engine 1 is a water-cooled 4-cycle in-line 3-cylinder engine, in which a cylinder axis A is inclined forward. Crankshaft 3
Is oriented horizontally in the vehicle width direction.

In the engine 1, a cylinder block 5, a cylinder head 6, and a head cover 7 are sequentially laminated and connected to a front upper mating surface of a crankcase 4 in which the crankshaft 3 and a transmission (not shown) are housed. The piston 8 is slidably inserted into a cylinder bore 5a of the cylinder block 5, and the piston 8 is connected to the crankshaft 3 by a connecting rod 9. An oil pan 16 is connected to the lower mating surface of the crankcase 4, and an oil filter 1 is attached to a front wall of the oil pan 16.
6a is mounted.

Each of the lower surfaces of the cylinder head 6 is provided with a combustion recess 6a at a portion opposed to each of the cylinder bores 5a.
0 electrode portions are inserted and arranged. Each combustion recess 6a has two intake valve openings 11, 11 and two exhaust valve openings 12, 12 for each cylinder. Each intake valve opening 11 is led to a rear wall 6b of the cylinder head 6 by an intake port 11a, and each exhaust valve opening 12 is led to a front wall 6c of the cylinder head 6 by an exhaust port 12a.

An exhaust pipe (not shown) is connected to the exhaust port 12a of the front wall 6c. An intake pipe 13 is connected to an intake port 11a of the rear wall 6b, and a throttle body 15 having a throttle valve 14 built therein is connected to the intake pipe 13. An air cleaner (not shown) is connected to an air suction port of the throttle body 15.

A valve hole 15a for mounting a fuel injection valve (not shown) is formed in a portion of the throttle body 15 downstream of the throttle valve 14. The fuel injection valve is arranged to inject fuel from the intake port 11a toward the intake valve opening 11.

An intake valve 18 is provided at each intake valve opening 11.
An exhaust valve 19 is disposed in each exhaust valve opening 12 so as to be urged in a closing direction by a spring 20. Each intake valve 18 is driven by an intake camshaft 22 disposed in parallel with the crankshaft 3, and each exhaust valve 19 is driven to open and close by an exhaust camshaft 23 disposed similarly.

The intake camshaft 22 and the exhaust camshaft 23 are rotatably supported by a bearing 24 integrally formed on the upper surface of the cylinder head 6 and a cam cap 25 fixed to the bearing 24 by bolts. Have been.

Mounting flanges 22a and 23a are integrally formed on the right end portions of the intake cam shaft 22 and the exhaust cam shaft 23, and cam sprockets 26 and 27 are fastened and fixed to the mounting flanges 22a and 23a by bolts 28, respectively. Have been. Each of the cam sprockets 26 and 27 and a crank sprocket (not shown) detachably attached to the right end of the crankshaft 3 are connected to a timing chain 29.
Are connected by The outer diameter of the cranks plot is set to the same outer diameter as the crank journal of the crankshaft 3.

In this manner, the rotation of the crankshaft 3 is transmitted to the intake camshaft 22 and the exhaust camshaft 23 via the timing chain 29 at a reduced speed of 回 転 rotation, and the intake valve 18 and the exhaust valve 19 are opened and closed. A cam drive mechanism is configured. Reference numeral 30 denotes an automatic tensioner for automatically adjusting the tension of the timing chain 20, and reference numeral 31 denotes a chain guide.

On the right side of the engine 1 in the vehicle width direction, there is formed a chain arrangement chamber 33 extending in the direction of the cylinder axis A so as to pass through the head cover 7, the cylinder head 6, and the cylinder block 5. Each of the cam sprockets 26, 27 constituting the cam drive mechanism therein
And a timing chain 29 are housed and arranged. The cylinder head portion of the chain arrangement chamber 33 is oil-tightly surrounded by an inner wall 34 and an outer wall 35 of the engine.

The vehicle body frame 2 on which the engine 1 is suspended is provided with left and right steel pipe side frame portions 2a and 2b extending rearward from the head pipe (not shown) while extending in the vehicle width direction. The engine 1 is mounted between the left and right side frame portions 2a, 2b.

A mount boss 36 is formed on the rear upper wall of the crankcase 4 of the engine 1, and a mount boss 37 is formed on the rear wall. The mount bosses 36 and 37 are connected to the left and right side frame portions 2.
It is bolted and fixed to a suspension bracket (not shown) or the like which is stretched and joined between a and 2b.

The left and right side walls of the cylinder head 6 of the engine 1 are suspended and supported by the side frames 2a and 2b, respectively. A boss 6d is integrally formed on the left side wall of the cylinder head 6, and the boss 6d protrudes outward in the vehicle width direction. The boss portion 6d is fastened and fixed to a bracket 38 joined to the left side frame portion 2a by bolts 39.

A bolt insertion hole 35a is formed in the outer side wall 35 of the right side wall of the cylinder head 6 which constitutes the chain arrangement chamber 33, and the inner side wall 34 is coaxial with the insertion hole 35a. As the inside screw hole 34a
Are formed. The insertion hole 35a and the inner screw hole 34
“a” is located substantially at the center of the portion surrounded by the timing chain 29.

A bracket 40 is joined to the right side frame portion 2b, and the bracket 40 is connected to the outer wall 35 and the inner wall 34 by mounting bolts 41.
It is supported and fixed by. This mounting bolt 41
Is composed of a cylindrical first bolt 42 having a screw hole 42a formed in the axis thereof and a second bolt 43 screwed to the first bolt through the bracket 40.

The first bolt 42 has a male thread 42b screwed into the inner threaded hole 34a of the inner wall 34, a stopper 42c abutting on the axially outer end face of the threaded hole 34a of the inner wall 34, The outer wall 35 has a flange portion 42d that comes into contact with the axially outer end surface of the insertion hole 35a. Thus, the screwing amount of the first bolt 42 is regulated, and the rigidity of the outer wall 35 is improved by slightly pressing the outer wall 35 by the flange portion 42d. The space between the first bolt 42 and the insertion hole 35 is oil-tightly sealed by an O-ring 44.

The first bolt 42 is inserted through the insertion hole 35 a of the outer wall 35 and is screwed and fixed to the inner screw hole 34 a of the inner wall 34. The second bolt 43 is connected to the first bolt 42.
The bracket 40 is screwed and fixed to the screw hole 42 a of the bracket 40 and the first bolt 42.

Thus, the engine 1 is fixed to the vehicle body frame 2 with bolts. That is, since the engine 1 is directly fixed to the vehicle body frame 2 without the intervention of the elastic member, the rigidity of the engine itself contributes to the rigidity of the entire vehicle body frame, and a high vehicle body rigidity can be obtained.

Next, the operation and effect of this embodiment will be described.

According to the engine mount structure of this embodiment, the first bolt 42 of the mount bolt 41 is screwed and fixed to the inner wall 34 by passing the outer wall 35 of the chain arrangement chamber 33 and the second bolt 43 is fixed to the side. Since the first bolt 42 is screwed and fixed so as to sandwich the bracket 40 of the frame portion 2b, the inner wall 34 having high rigidity is
1 enables the engine 1 to be fastened directly to the side frame portion 2b to secure the rigidity of mounting the engine 1 to the vehicle body frame 2, and the engine 1 to increase the rigidity of the entire vehicle body frame 2.

In the present embodiment, the mounting bolt 41
Is set inside the inner wall 34,
The fastening force can be secured without increasing the vehicle width dimension of the engine 1, and an increase in the size of the body frame 2 can be prevented.

Since the width of the engine 1 can be reduced, as shown in FIG.
The amount of offset between the vehicle and the frame center C2 can be reduced, and the influence of cornering characteristics and the like on running performance can be prevented.

Further, since the portion of the chain arrangement chamber 33 which is the side wall of the engine 1 is fixed to the side frame portion 2b, the mounting in the case where the mount boss portion is formed by overhanging the front and rear walls of the conventional cylinder head. A reduction in rigidity and an increase in engine weight can be avoided.
Interference with the exhaust system can be avoided, and the degree of freedom in frame design can be increased.

Further, in this embodiment, when the engine is assembled, the timing chain 29 is assembled into the chain disposition chamber 33, and the first bolt 42 can be screwed thereafter. 42 does not get in the way.

In this embodiment, the mounting bolt 41
Are arranged so as to be located in a portion of the cylinder head 6 surrounded by the timing chain 29, so that the tightening allowance and mounting rigidity of the mount bolt 41 can be easily ensured, and the timing chain 29, the respective cam sprockets 26 and 2 are secured.
The mount bolt 41 can be set at the optimum position without interfering with the position of the mount bolt 41.

In the above-described embodiment, the case where the four-cycle parallel three-cylinder engine is mounted has been described. However, the present invention is not limited to this.
Applicable to engines with more than cylinders.

Here, in the case of a parallel four-cylinder engine, there is a center chain type in which a timing chain is disposed between the second and third cylinders. In the case of the center chain type, mounting rigidity can be increased by mounting the left and right side walls of the cylinder head as they are. However, in the case of the center chain type, the timing chain is arranged at the axial center of the crankshaft, so that one crank journal is inevitably added, resulting in an increase in cost. In addition, since the cam drive teeth are formed at the center of the crankshaft, the outer diameter of the crank sprocket is larger than the outer diameter of the crank journal. For this reason,
The outer diameter of the cam sprocket disposed on the camshaft side also increases, and the size of the entire engine increases. On the other hand, in the case of a side-chain type four-cylinder engine, since the crank sprocket for driving the cam can be provided separately, the crank sprocket can be made substantially the same size as the outer diameter of the crank journal. In addition, the above-described problem of enlargement can be avoided.

[Brief description of the drawings]

FIG. 1 is a left side view of an engine for explaining an engine mount structure of a motorcycle according to an embodiment of the present invention.

FIG. 2 is a rear view of the engine as viewed obliquely from above and behind the engine.

FIG. 3 is a right side view of the engine.

FIG. 4 is a cross-sectional rear view of a mount portion of the engine.

FIG. 5 is a sectional view of an engine mount for explaining a process of establishing the present invention.

FIG. 6 is a view showing a conventional general engine mount structure.

[Explanation of symbols]

 1 4 cycle parallel 3 cylinder engine 2 Body frame 2a, 2b Side frame 6 Cylinder head 29 Timing chain 33 Chain arrangement chamber 34 Inner side wall 35 Outer side wall 35a Insertion hole 41 Mount bolt 42 First bolt 42a Screw hole 42d Flange part 43 2 volts

Claims (3)

[Claims] 1. An engine mount for a motorcycle in which an engine having a chain arrangement chamber surrounded by an inner wall and an outer wall on a side portion in a vehicle width direction is mounted between left and right side frame portions of a body frame extending in a vehicle front-rear direction. In the structure, the engine is fixed to the side frame portion by mounting a mount bolt on the side frame portion, inserting the mount bolt through an insertion hole formed in the outer wall, and screwing the mount bolt to the inner wall. A motorcycle engine mount structure characterized by the following. 2. The mounting bolt according to claim 1, wherein the mounting bolt has a screw hole formed at an axis thereof and a flange formed at an outer end thereof, and is screwed to the screw hole of the first bolt. The first bolt is screwed and fixed to the inner wall in a state where the flange portion is in contact with the outer end surface of the insertion hole of the outer wall, and the second bolt is fixed to the second bolt. An engine mount structure for a motorcycle, wherein the side frame portion is screwed and fastened to a first bolt so as to be clamped and fixed to the first bolt. 3. The engine mount structure for a motorcycle according to claim 1, wherein the mount bolt is disposed so as to be located in a portion of the cylinder head surrounded by a timing chain.