JPH02112625A - Building structure for crankcase internal part in engine - Google Patents

Abstract

PURPOSE:To avoid an engine from being formed in large size by constituting a building objective part of a main unit part and a supporting shaft and inserting the main unit part from an opening, formed in a roof wall or the like of a crankcase, while the supporting shaft from an insertion hole, formed in a side wall of the crankcase, so as to be built in the case. CONSTITUTION:In an engine for motorcycle, a balancer shaft 47 is respectively arranged before and after a crankshaft 18 in a lower case 24 of a crankcase 10. Here the balancer shaft 47 is constituted of a balancer main unit 49 and a supporting shaft 51 inserted to the inside of the balancer main unit 49. In assembly of the balancer shafts 47, 48, the balancer shaft 50 is inserted from an insertion hole 24f formed in a side wall of the lower case 24, while the balancer main unit 49 is inserted into the case from a mounting opening 24i, normally mounting an oil pan to be attached, and from a work opening formed in a roof rear part of an upper case. Subsequently, the assembly is completed in the case by inserting the supporting shaft 50 into the balancer main unit 49.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure for assembling parts parallel to a crankshaft into a crankcase, and particularly to a structure for assembling parts parallel to a crankshaft in a direction perpendicular to the crankshaft. This invention relates to an improvement in an assembly method that enables assembly without forming a large insertion hole in the side wall of a crankcase.

[Conventional technology]

For example, motorcycle engines generally employ a structure in which not only the crankshaft but also a transmission, a balancer, etc. are assembled into the crankcase. In such an engine, a problem arises in how to assemble each transmission shaft of the transmission, the shift fork, or the balancer shaft of the balancer device. In other words, although these parts are arranged parallel to the crankshaft, they have large protrusions in the direction perpendicular to the axis such as the shift fork and balance weight, so if they are inserted directly from the side wall of the crankcase, a large opening is required. . On the other hand, since the loads of each axis act on this side wall, it is not practical to form such a large diameter opening.

Conventionally, the structure for assembling the above-mentioned parts has been such that the crankcase is divided into upper and lower parts, and a balancer shaft or the like is arranged between the divided surfaces in line with the crankshaft (for example, 59-79020).

[Problem that the invention seeks to solve]

However, as in the conventional structure described above, when the parts are arranged in parallel between the upper and upper divided surfaces, the length of the crankcase increases accordingly, resulting in an increase in the size of the engine. Furthermore, since the arrangement position is limited to between these divided planes, there is also the problem that the degree of freedom in design is correspondingly low.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and it can be easily arranged at a position other than between the dividing surfaces without forming a large insertion hole in the side wall of the crankcase, and it is possible to increase the size of the engine. It is an object of the present invention to provide a structure for assembling internal parts of an engine crankcase, which can avoid this problem and ensure flexibility in layout design.

[Means for Solving the Problems] The present invention provides a structure for assembling a component having an axis parallel to the crankshaft into the crankcase of an engine, in which the component is assembled into a cylindrical portion parallel to the crankshaft. a main body having a main body; and a main body inserted into the main body to support the main body;
and a support shaft supported by the crankcase, and an opening for assembly work that can be opened and closed by a lid member is provided in the top or bottom wall of the crankcase, and an insertion hole is provided in the side wall, so that the opening can be inserted through the opening. The main body is inserted and arranged parallel to the crankshaft, the support shaft is inserted into the main body through the insertion hole, and the support shaft supports the main body.

Here, the components in the present invention include a balancer shaft.

This includes parts such as shift forks that are arranged parallel to the crankshaft and have a portion that largely protrudes in a direction perpendicular to the crankshaft.

In addition, when forming a working opening in the top wall of the crankcase, for example, use the pleather cover that constitutes the breather chamber also as an opening/closing lid, and when forming a working opening in the bottom wall, for example, use the opening/closing lid for the oil pan. Can be used for both.

[Effect]

According to the assembly structure according to the present invention, the parts to be assembled are composed of a main body and a support shaft, the main body is inserted through the working opening, the support shaft is inserted through the insertion hole in the side wall of the crankcase, and
Since it is assembled inside the crankcase, compared to the case where the crankcase is arranged in parallel between the split surfaces of the crankcase as described above, the length of the front and rear of the crankcase can be shortened, avoiding an increase in the size of the engine, and there are no restrictions on the location of the crankcase. This is not very common, and the degree of freedom in design can be improved. Further, since the structure is such that only the support shaft is inserted from the side wall of the crankcase, the diameter of the insertion hole may be approximately the same as the diameter of the support shaft, and there is no need to provide a large opening in the side wall of the crankcase.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 8 are diagrams for explaining one embodiment of the present invention.

In the figure, l is a motorcycle equipped with the engine of this embodiment, and at the front end of the body frame 2 of this, a front fork 4, which pivotally supports a front wheel 3 at its lower end, is supported so as to be steerable left and right. At the lower end of the center, a rear arm 6, which pivotally supports the rear wheel 5 at the rear end, is pivoted to be able to swing up and down, and a large fuel tank 7 and a seat 8 are mounted on the upper part in order from the front. Further, an engine unit 9 is suspended and supported on the lower front side of the vehicle body frame 2.

-F engine unit 9 is an air-cooled 4-cycle parallel 2
The cylinder block 11. The cylinder head 12 and head cover 13 are mounted on a vehicle and are stacked in a forward tilted state at approximately 45 degrees with respect to a horizontal plane.

Left and right cylinders 11a of the cylinder block 11.

A combustion chamber 14 is formed in the upper part of the combustion chamber 11b by the pistons 14a, 14b and the recesses 12a, 12b of the cylinder head 12, and an intake valve 15a is connected to the intake and exhaust ports communicating with the combustion chamber 14. Book.

Two exhaust valves 15b are arranged. Each intake valve 15a
, intake camshaft 16a for exhaust valve 15b, exhaust camshaft 16
A driven sprocket 16c is fixed to the right end of the sprocket b when viewed from the rear of the vehicle (the same applies hereafter).

Each piston 14a, 14b has a connecting rod 17a,
Crank arm portions 18a, 18 each having a pair of webs of the crankshaft 18 connected by a crank pin 17b;
b, and both crank arm portions 18a of the crankshaft 18.

The portion between 18b and 18b is supported by a solid bearing 19c, on the left.

The right outer portion is supported by left and right bearings 19a and 19b, respectively.

The above-mentioned crankcase 10 has a top and bottom split structure in which it is divided into upper and lower cases 23° and 24.
is slanted so that the front side is lower when mounted on a vehicle. Above left,
The right solid bearings 19a to 19C are formed on the front side of this dividing surface A. Further, a pivot portion 24a for pivotally supporting the front end of the rear arm 6 is integrally formed at the rear end portion of the lower case 24.

A driving sprocket 18c is integrally formed on the right side protrusion of the crankshaft 18, and a cam 20 is wound between the sprocket 18c and the driven sprockets of the camshafts 16a and 16b. The cam chain 20 includes chain case parts 12c and 11c that are bulged from the right side wall of the cylinder head 12, cylinder block 11, and upper case 23.

and 23a.

A pump drive gear 25 is attached to the outer end of the crankshaft I8 from the drive sprocket 18c. Below this, lubricating oil from an oil tank (not shown) having an oil cooler JIIK is supplied to the bearings 198 to 19c.
a feed pump 26 for supplying lubricant-required parts such as;
A scavenge pump 27 for feeding %l'ff oil in an oil pan 28 mounted on the lower surface of the lower cover 24 into an oil tank is arranged in parallel, and the pump drive gear 25 is an input to the feed pump 26. The manual gear 26a is the input gear 27a of the scavenge pump 27.
are meshed sequentially.

Further, a water pump 53 for circulating cooling water is disposed on the right side wall of the crankcase IO in a portion in front of the chain case portion 23a. Suction port 5 of this water pump 53
3a is connected to a radiator (not shown), and the discharge port 53b is connected to the cooling jacket 11d of the cylinder block 11, respectively. Further, a driven gear 53d fixed to the impeller shaft 53C meshes with a drive gear 47c fixed to the right end of a front balancer shaft 47, which will be described later.

A transmission main shaft (main shaft) 32 is disposed in a hole on the rear side of the crankshaft 18 of the upper cover 23 and above the dividing surface A, and a portion slightly rearward of the transmission main shaft 32 between the dividing surfaces has a hole. A speed change subshaft (drive shaft) 35 is provided. This speed change main shaft 32 has bearings 32b at both left and right ends,
32c, the speed change subshaft 35 is supported by bearings 35b and 35c, respectively. Right bearing 32c of the speed change main shaft 32
is attached to the right side wall of the upper case 23 via a housing 32d having a larger diameter than the speed change gear 32a attached to the main shaft 32. An opening for removing the main shaft 32 is formed in the left bearing 32b, and a cap 328 is fitted into the opening. This cap 32e and the oil seal 3 on the outside of the left bearing 35b of the subshaft 35
5d is pressed by a sheet metal type presser plate 35e fixed to the left side wall of the crankcase 10. The housing 32d is for inserting the speed change main shaft 32 from the right side wall.

In addition, a wet multi-plate clutch 33 is located at the right end of the speed change main shaft 32.
A large reduction gear 33b fixed to the outer 33a of the clutch 33 meshes with a small reduction gear 22 fixed to the crankshaft 18. The speed change main shaft 32. Speed change gears 32a and 3 of each stage mounted on the subshaft 35
5a are in mesh with each other, thereby forming a constant mesh type transmission.

The left end of the speed change subshaft 35 projects outward from the left side wall of the crankcase 10, and a rear wheel drive sprocket 36 is attached to the projecting portion, and the sprocket 36 and the rear end 5
A transmission chain 37 is wound between the driven sprockets 5a. A chino cover 38 is disposed on the outside of the sprocket 36 to cover it.

Further, a change pedal 39 is swingably provided on the lower side of the drive sprocket 36, and this has a shift shaft 40 disposed on the upper side with a universal joint 41a at both ends. They are connected by a connecting rod 41b extending vertically outside the throat 36. Further, a case cover 42 is provided on the outside of the connecting rod 41b and the shift shaft 40 to cover them, and the chino cover 38 serves as a partition member between the connecting rod 40 and the sprocket 36.

Is the shift shaft 40 oscillating degrees? - is connected to a shift drum 55 by a beam 54. Cam groove 55a of the drum 55
A drive pawl 56b of the shift fork 56 (main body) is slidably fitted in the shift fork 56 (main body), and a drive pawl 56C is slidably fitted in the shift gears 32a, 35a (shift gears 32a, 35a) 1132d, 35e. There is.

Further, the support cylinder portion (cylindrical portion) 56 of this shift fork 56
d is supported by a support shaft 56a. The support shaft 5
6a is an upper case inserted through an insertion hole 23d formed in the upper case 23, and the tip end is inserted into the support hole 2 formed in the upper case 23.
It is supported by 38.

Note that 23f is a stopper plate for preventing the support shaft 56a from being removed.

A front balancer shaft 47 is located in front of the crankshaft 18 of the lower case 24 and below the dividing surface A.
Rear balancer shafts 48 are arranged parallel to the crankshaft 18 at the rear side of the crankshaft 18 of No. 3 and above the dividing plane A, and the MIL connecting the axes of both balancer shafts 47 and 48 is the crankshaft. It is located in front of the axis of the shaft 18. - The front and rear balancer shafts 47 and 48 have a structure in which a support shaft 50 is inserted into the balancer main body (main body portion) 49, and a needle bearing 51 is arranged between them.

This support shaft 50 is inserted through insertion holes 23b and 24f formed in the side walls of the upper and lower cases 23.24, and its tip is inserted into the support hole 23b formed in the right side wall of the upper and lower cases 23.24.
3c and 24g, respectively, and their rear ends are fixed to the left side wall by key plates 47b and 48b. The balancer main body 49 is formed by integrally forming a weight part 49b at both ends of a cylindrical body 49a and a positioning part 49c in the center, and the weight part 49b is connected to each crank arm part 18a of the crankshaft 18, It is located between 18b.

The positioning portion 49c is connected to the balancer shaft 47.48.
The balancer shafts 47 and 48 are inserted into guide grooves 2a of a positioning plate 52 fixed to the crankcase, thereby positioning each balancer shaft 47, 48 in the axial direction. Further, driven gears 47a and 48a fixed to the left end of the balancer body 49 are both meshed with the balancer gear 21, so that they rotate in the opposite direction to the crankshaft 18.

At the rear of the ceiling wall of the upper case 23, there is provided the above-mentioned rear balancer shaft 48. A balancer shaft opening 57a for assembling the shift fork 56 and a drum opening 57b are formed. Further, in the portion between both openings 57a and 57b of the ceiling wall, there is a first breather chamber constituting the lower half of the first and third breather chambers, which will be described later. The third compartments 57c, 57d are formed in a concave shape, and through holes 57e are formed in the bottom walls of both corner compartments 57c, 57d.

A breather cover 58 is attached to the upper surface of the upper cover 23 so as to be openable and closable by tightening bolts, and covers the eight compartments 57a to 57d. This breather cover 58 serves as an opening/closing lid that opens and closes both openings 5Ta and 57b, and also has a breather chamber that separates lubricating oil mixed in the externally released air to absorb fluctuations in the internal pressure of the crankcase. It consists of

The breather cover 58 has a bowl shape that bulges upward, and is formed with a partition wall 58a that has the same shape in plan view as the corner chambers 57c and 57d and has a communication port 58b. Further, a partition plate 59 that substantially closes the opening 57a is attached to the breather cover 58 by bolts to a portion of the breather cover 58 corresponding to the balancer shaft opening 57a. Note that there is a slight gap between this partition plate 59 and the periphery of the opening 57a. As a result, an oil breather is constructed in which the oil-mixed air flowing in from the drum intake chamber 57b sequentially passes through the first to third pleather chambers 58c to 58e and is sent to the air cleaner from the connecting pipe 58f by an introduction hose (not shown). ing.

Further, as described above, the oil pan 28 is attached to the bottom surface of the lower case 24, and when the oil pan 28 is removed, the front balancer shaft 47 is exposed downward from the attachment opening 24i. It has become. That is, the opening 2
4i is an opening for assembling the front balancer shaft 47.

Note that 43 is a starter motor, and a drive gear 43b attached to an output shaft 43a of the starter motor meshes with a starting gear 46 attached to the crankshaft 18 via a one-way clutch via an idle gear 45.

Next, the effects of this embodiment will be explained.

First, the shift fork 56 and the front and rear balancer shafts 47.
The procedure for assembling 48 into the crankcase 10 will be explained.

Shift fork 56. For the rear balancer shaft 48, remove the breather cover 58 and open the openings 57a, 57b.
First, insert the shift drum 55 from the side, insert the shift fork 56 from the opening 57b, and insert the drive pawl 56b into the guide groove 5 of the shift ram 55.
5a, and the drive claw 56c is fitted to the gearbox 3.
Fit into the shift grooves 32d and 35e of 2835g.

In this state, the support shaft 56a is inserted into the support cylinder part 56d through the insertion hole 23 d-t, and its tip is inserted into the support hole 23e, and the rear end surface is further pressed and fixed with the stopper plate 23r. .

Next, the balancer main body 49 of the rear balancer shaft 48 is inserted through the opening 57a, the left and right weight portions 49b and 49b are positioned within the crank arm portions 18a and 18b, and the driven gear 48a is engaged with the balancer gear 21. In this state, insert the support shaft 5o into the insertion hole 23 on the left side wall of the upper case 23.
b into the balancer main body 49, and its tip is inserted into the support hole 23c on the right side wall. Furthermore, the support shaft 5
A key plate 48b is fitted to the rear end of the upper case 23, and the plate 48b is bolted and fixed to the left side wall of the upper case 23. Finally, the guide groove 52a of the positioning plate 52 is fitted into the positioning portion 49c.

Regarding the front balancer shaft 47, remove the oil pan 28, insert the balancer body 49 of the front balancer shaft 47 from the mounting opening 24i, connect the driven gear 47a to the balancer gear 21, and connect the drive gear 47c to the driven gear 53 of the water pump 53.
d, the support shaft 50 is inserted, and the key plate 47b is fixed, and the positioning plate 52 is attached.

When the engine of this embodiment in which the balancer shafts 47, 48, etc. are assembled in this manner is started, the rotation of the crankshaft 18 is transmitted from the balancer gear 21 to each balancer shaft 47, 48, and the engine vibration is caused by the rotation of the shafts. Reduced. Furthermore, when the change pedal 39 is moved up and down, this movement is transmitted to the shift drum 55 via the connecting rod 41b and the shift shaft 40, and the rotation of the drum 55 causes the shift fork 56 to move in the axial direction. You can change gears.

Further, due to the rotation of the speed change gears 32a and 35a, air containing lubricating oil in the crankcase 10 is pushed into the breather cover 58 through the opening 57b, and expands and contracts in the first to third breather chambers 58c to 58e. Connecting pipe 58f
reached and is sent to the air cleaner. During the expansion and contraction, the lubricating oil in the air is separated and falls into the crankcase 10 through the through hole 57e and the gap around the partition plate 59, and air containing almost no lubricating oil is sent to the air cleaner. .

As described above, in this embodiment, the balancer shafts 47, 48 and the shift fork 56 can be arranged at positions other than between the dividing surfaces, and the length of the crankcase can be shortened to avoid increasing the size of the engine. Moreover, since it can be freely arranged at a position other than between the dividing planes, a degree of freedom in arrangement design can be ensured.

In addition, insertion holes 23b, 2 formed in the side wall of the crankcase.
3d and 24f are the diameters of the weight portion 49b and the shift fork 5.
It is not affected by the length of the support shaft 6, and the diameter of the support shaft is sufficient.Therefore, there is no need to form a large opening in the side wall of the crankcase, and from this point of view as well, flexibility in placement can be ensured.

In the above embodiment, the balancer shaft and the shift fork were used as examples of parts to be assembled, but the parts to be assembled are not limited to these, and are arranged parallel to the crankshaft and in the direction perpendicular to the axis. It is effective if it has a large protrusion.

Furthermore, in the above embodiments, the case where the crankcase is divided into upper and lower parts has been described, but the present invention can of course be applied to the case where the above-mentioned parts are assembled into a crankcase which is divided into left and right parts.

〔Effect of the invention〕

As described above, according to the engine crankcase internal parts assembly structure according to the present invention, the parts to be assembled are composed of the main body part and the support shaft, and the main body part is formed on the top wall or the bottom wall of the crankcase. The support shaft is inserted through the insertion hole formed in the side wall of the crankcase, and assembled inside the case, so the placement position can be set freely, avoiding an increase in the size of the engine. This has the effect of expanding the degree of freedom in design.

[Brief explanation of drawings]

1 to 8 are diagrams for explaining a balancer shaft and shift fork assembly structure according to an embodiment of the present invention, and FIG. 1 is a partially sectional side view of an engine to which the structure is applied; Fig. 2 is a developed cross-sectional plan view, Fig. 3 is a plan view of the upper case, Fig. 4 is a cross-sectional plan view of the front balancer shaft portion, and Fig. 5 is a plan view of the upper case.
The figure is a cross-sectional plan view of the shift fork part, FIG. 6 is a cross-sectional side view of a part of the breather cover, FIG. 7 is a plan view thereof, and FIG.
The figure is a left side view of a motorcycle equipped with the engine. In the figure, 9 is an engine unit, 10 is a crankcase, 18 is a crankshaft, 23b, 23d, 24f are insertion holes, 23c, 23e, 24g are support holes, 24i, 57
a, 57b are work openings, 28.58 are oil pans, pleaser covers (lid members), 47.48.56 are front and rear balancer shafts, shift forks (parts inside the crankcase),
49 is a balancer main body (body part), 49a and 56d are cylindrical parts, and 50 and 568 are support shafts. Figure 5

Claims (1)

[Claims] (1) In a structure for assembling parts having an axis parallel to the crankshaft into the crankcase of an engine, the parts are inserted into a main body having a cylindrical part parallel to the crankshaft, and into the main body. and a support shaft supported by the crankcase, and an opening for assembly work that can be opened and closed by a lid member is provided in the top or bottom wall of the crankcase, and a side wall is provided. An insertion hole is provided in the main body, and the main body is inserted through the opening and arranged parallel to the crankshaft, and the support shaft is inserted into the main body through the insertion hole, and the main body is supported by the support shaft. An assembly structure for internal parts of an engine crankcase, which is characterized by: