JP2001179556A - Method of working transmission case for unit swing type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of working a transmission case for unit swing type engine at a low cost by using the same production working equipment in common to plural transmission cases having a different size. SOLUTION: In a method of working transmission cases 3, 3' for unit swing type engine formed of a transmission case main body 3A extended backward of a car body from one side of a crank case of the engine, a transmission case cover fastened to the transmission case main body 3A by a bolt and formed with a belt chamber S1 for housing a V-belt type automatic transmission inside thereof, and gear chamber covers 7, 7' fastened to a rear of the transmission case main body 3A by bolts and formed with a gear chamber S2 for housing a reduction gear inside thereof in the described belt chamber S1, at least each one (54A, 54B, 55A, 56A) of plural knock pin holes (case working positioning parts) 34A, 34B, plural knock pins (belt chamber assembling positioning parts) 55A, 55B, 55B', and plural knock pin holes (gear chamber assembling positioning parts) 56A, 56B, 56B' are formed in the same coordinate position in relation to the plural transmission cases 3, 3' having a different size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of machining a transmission case of a unit swing type engine.

[0002]

2. Description of the Related Art For example, a unit swing type engine mounted on a small scooter-type motorcycle integrally includes an engine as a drive source and a transmission mechanism including a V-belt type automatic transmission, a reduction gear and the like in a transmission case. And configured as a unit. The transmission case of this type of unit swing type engine has a transmission case body extending from one side of the crankcase of the engine to the rear of the vehicle body, and is fastened to the transmission case body by bolts and has a V inside.
A transmission case cover forming a belt chamber for accommodating the belt-type automatic transmission, and a gear chamber fastened by bolts to a rear portion of the transmission case main body and forming a gear chamber for accommodating a reduction gear therein inside the belt chamber. It consists of a cover.

By the way, when processing and assembling the transmission case of such a unit swing type engine, positioning means such as knock pins are used, and the transmission case is provided with a plurality of case processing positioning portions (used for machining the transmission case). A plurality of belt chamber assembling positioning parts (knock pin holes) used for assembling with the transmission case cover and a plurality of gear chamber assembling positioning parts (knock pin holes) used for assembling with the gear chamber cover. Is formed.

[0004]

Conventionally, however, the coordinates of the various positioning parts are independently determined for each of the transmission cases having different sizes. Therefore, it is necessary to provide dedicated production processing equipment for each size of the transmission case. However, this has caused an increase in cost.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a unit swing type in which production processing equipment can be shared for a plurality of transmission cases of different sizes and cost can be reduced. An object of the present invention is to provide a method of machining a transmission case of an engine.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a transmission case body extending from one side of a crankcase of an engine to the rear of a vehicle body, and is fastened to the transmission case body by bolts. A transmission case cover forming a belt chamber for accommodating a V-belt type automatic transmission therein, and a gear chamber fastened by bolts to a rear portion of the transmission case main body and accommodating a reduction gear therein are provided inside the belt chamber. As a method of machining a transmission case of a unit swing type engine including a gear chamber cover formed in a plurality of cases, a plurality of case processing positioning portions used for machining the transmission case body, a transmission case body, and the transmission case cover A plurality of belt chamber assembling positioning portions and a plurality of gear chambers used to assemble the transmission case body with the gear chamber cover Characterized in that so as to form the same coordinate position with respect to a plurality of different transmission case of the at least one size of the standing positioning part.

Therefore, according to the present invention, at least one of the various positioning portions is formed at the same coordinate position for a plurality of transmission cases having different sizes, so that a production processing facility can be provided for a plurality of transmission cases having different sizes. They can be shared, thereby reducing costs.

[0008]

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

FIG. 1 is a partial plan sectional view of a unit swing type engine, FIG. 2 is a plan sectional view of a four-cycle engine part of the unit swing type engine, and FIG. 3 is a side sectional view of the same.

The unit swing type engine 10 according to the present embodiment is mounted on a scooter type motorcycle (not shown), which is a forced air-cooled four-cycle engine (hereinafter simply referred to as engine) 1, V The transmission mechanism including the belt-type automatic transmission 2 is compactly incorporated in the transmission case 3 to constitute a unit.

Here, as shown in FIG.
A transmission case main body 3A extending from the left side of the crankcase 1a of the engine 1 toward the vehicle body; a transmission case cover 4 attached to a side opening of the transmission case main body 3A with bolts 5 and 6; A gear chamber cover 7 is attached to the rear portion of the transmission case main body 3A by bolts 8.

A belt chamber S1 covered by the transmission case cover 4 is formed inside the transmission case body 3A, and the V-belt type automatic transmission 2 is accommodated in the belt chamber S1.

A gear chamber S2 covered by the gear chamber cover 7 is formed inside the belt chamber S1, and reduction gears 50 and 51 described later are housed in the gear chamber S2.

Next, a schematic configuration of the engine 1 will be described.

The engine 1 is a single-cylinder engine. As shown in FIG. 3, a single cylinder 11 is formed in a cylinder body 9 which is disposed substantially horizontally toward the front of the scooter type motorcycle. A piston 12 is slidably fitted in the cylinder 11. And piston 1
2 is connected via a connecting rod 14 to a rotatable crankshaft 13 arranged in the vehicle width direction.

An intake port 16 and an exhaust port 17 are formed above and below a cylinder head 15 attached to the cylinder body 9, respectively. Valve 1
9 is opened and closed at appropriate timing, whereby a required gas exchange is performed in the cylinder 11.

That is, as shown in FIG.
The exhaust valve 19 and the exhaust valve 19 are slidably inserted and held by valve guides 20 and 21 press-fitted into the cylinder head 15, respectively, and these are urged to the closing side by springs 22 and 23. 2
5 are in contact with each other. Here, each rocker arm 2
The intermediate portions 4 and 25 are pivotally attached to the shafts 26 and 27 so as to be freely swingable. The other ends of the respective portions are in contact with a cam formed integrally with the cam shaft 28.

A chain sprocket (not shown) is mounted on one end of the camshaft 28. An endless chain sprocket is mounted between the chain sprocket and a chain sprocket 29 mounted on an intermediate portion of the crankshaft 13. The cam chain 30 is wound (see FIG. 2).

The rotation of the crankshaft 13 is transmitted to the camshaft 28 via a chain sprocket 29, a cam chain 30, and a chain sprocket (not shown) attached to the camshaft 28, and the camshaft 28 is driven at a predetermined speed. When driven at (（speed of the crankshaft 13), the intake valves 18 and the exhaust valves 19 are driven by the rocker arms 24 and 25, and the intake ports 16 and the exhaust ports 17 are respectively opened and closed at appropriate timings. As a result, required gas exchange is performed in the cylinder 11 as described above.

On the other hand, as shown in detail in FIG. 2, the crankshaft 13 is rotatably supported by a pair of left and right bearings 31, and a cooling fan 32 is attached to one end (right end) thereof. Is provided with a generator 33. At the other end (left end) of the crankshaft 13, a wheel starter 34 and a drive pulley 35 constituting the V-belt type automatic transmission 2 are attached.

Here, the driving pulley 35 includes a fixed sheave 35a fixed to the end of the crankshaft 13 and a movable sheave 35b slidably supported along the crankshaft 13.
The movable sheave 35b and the crankshaft 1
A plurality of centrifugal weights 37 are accommodated in a space formed between the cam plate 36 and the cam plate 36 fixed to 3 so as to be movable in the radial direction. Then, the fixed sheave 3 of the driving pulley 35
A plurality of cooling fins 38 are formed integrally with 5a, and the fixed sheave 35a forms a cooling fan.

Incidentally, as shown in FIG.
An intake pipe 39 connected to the intake port 16 is attached to an upper portion of the intake pipe 5, and a carburetor and an air cleaner (not shown) are connected to the intake pipe 39. An exhaust pipe (not shown) is attached to the exhaust port 17 opening at the lower part of the cylinder head 15, and an exhaust muffler (not shown) is connected to the exhaust pipe.

The entire engine 1 having the above configuration is covered with an air shroud 40 made of resin, and a portion of the air shroud 40 facing the cooling fan 32 has a circular cooling air flow. The inlet 40 a is formed coaxially with the crankshaft 13. As shown in FIG. 2, a plug hole 40b that opens diagonally laterally is formed at the front end of the air shroud 40, and a circular hole 40c for confirming the top dead center is formed behind the plug hole 40b. And plug hole 4
A spark plug (not shown) is passed through Ob, and the spark plug is screwed to the cylinder head 15, and a rubber cap 41 is detachably fitted into the circular hole 40c for confirming the top dead center.

Next, the structure of the transmission mechanism of the unit swing type engine 10 will be described.

As shown in FIG. 1, a driven shaft 42, an intermediate shaft (not shown) and an output shaft (axle) 43 are provided at the rear of the transmission case 3.
Are arranged in parallel and rotatable with each other, and the driven shaft 42
, A driven pulley 44 and a centrifugal clutch 45 are attached.

The driven shaft 42 is provided with a hollow shaft 46.
Is rotatably supported, and a fixed sheave 44 a of the driven pulley 44 is attached to the inner end of the hollow shaft 46. A movable sleeve 47 is slidably fitted on the hollow shaft 46, and a movable sheave 44b of a driven pulley 44 is attached to an inner end of the movable sleeve 47. The movable sheave 44b is connected to the centrifugal clutch. 45, and a fixed sheave 44 by a spring 48 compressed between
It is urged to the b side. Then, an endless V-belt 49 is wound between the driven pulley 44 composed of the fixed sheave 44a and the movable sheave 44b and the driving pulley 35 on the crankshaft 13, so that the V-belt type automatic transmission 2 Is configured.

The centrifugal clutch 45 comprises a clutch inner 45a fixed to the outer end of the hollow shaft 46 and a drum-shaped clutch outer 45b fixed to the outer end of the driven shaft 42. .

On the other hand, a reduction gear (drive gear) 50 is integrally formed at an inner end of the driven shaft 42 facing the gear chamber S2, and a large-small and small-diameter unshown intermediate shaft (not shown). (Reduction gear and drive gear) are attached. The reduction gear (drive gear) of the intermediate shaft is meshed with the reduction gear (drive gear) 50, and the reduction gear (drive gear) (not shown) of the intermediate shaft has a large diameter attached to the output shaft 43. It is in mesh with a reduction gear (driven gear) 51.
A rear wheel 52 of a scooter-type motorcycle is attached to an end of the output shaft 43 protruding outward from the transmission case 3. In FIG. 1, reference numeral 53 denotes a kick lever for a kick starter.

Here, the transmission case machining method according to the present invention will be described with reference to FIGS. FIG. 4 is an inner view of the transmission case main body, and FIG. 5 is an inner view of the rear part of the transmission case and the gear chamber cover.

As shown in FIG. 4, the transmission case cover 4 is attached to the periphery of the side opening of the transmission case body 3A on which the transmission case cover 4 is attached (the joint surface with the transmission case cover 4). A plurality of bolt holes 3a into which the bolts 5 are screwed are formed. A knock pin hole 54A as a case processing positioning portion used for machining of the transmission case main body 3A and a transmission case cover 4 are provided in a lower front part of the periphery of the side opening of the transmission case main body 3A.
A knock pin hole 55A is formed as a positioning portion for assembling the belt chamber used for assembling the belt.

A knock pin hole 54B as a case processing positioning portion similar to the knock pin hole 54A is formed in the upper rear part of the periphery of the side opening of the transmission case body 3A.
A knock pin hole 55 as a positioning portion for gear chamber assembly similar to the knock pin hole 55A is formed at the rear.
B is formed.

On the other hand, a plurality of bolt holes 3b into which the bolts 8 for mounting the gear chamber cover 7 are screwed are formed on the periphery of the opening of the gear chamber S2 which is opened at the rear of the transmission case body 3A. Two knock pin holes 56A and 56B are formed as gear chamber assembling positioning portions used for assembling with the cover 7.

As shown in FIG. 5, the bolt hole 3a and the knock pin holes 56A, 56B at the periphery of the gear chamber cover 7 are provided.
Are formed with bolt holes 7a and two knock pin holes 57A, 57B as positioning portions for assembling the gear chamber.

Here, FIG. 5 shows a transmission case 3 'smaller in size than the transmission case 3 according to the present embodiment and a gear chamber cover 7' attached thereto by a chain line. 3 'is provided with one knock pin hole 55B' as a positioning portion for assembling the belt chamber and one knock pin hole 56B 'as a positioning portion for assembling the gear chamber. The two knock pin holes 5 are formed at positions different from 55B and 56B, and serve as remaining case processing positioning portions.
4A, 54B, one knock pin hole 55A as a gear chamber assembling positioning part and one knock pin hole 56A as a gear chamber assembling positioning part are provided with a large-sized transmission case 3.
Are formed at the same coordinate position.

A positioning portion for assembling a gear chamber is provided at a position corresponding to a knock pin hole 56B 'formed in the small-sized transmission case 3' of the small-sized gear chamber cover 7 'shown by a chain line in FIG. Knock pin hole 57B 'formed in large-sized gear chamber cover 7
7B, and one knock pin hole 57A as the remaining gear chamber assembly positioning portion is formed at the same coordinate position as the large size gear chamber cover 7.

As described above, in the present embodiment,
Two knock pin holes 54A, 54 as case processing positioning portions for transmission cases 3, 3 'having different sizes.
B and one knock pin hole 55A as a positioning portion for assembling the belt chamber and one knock pin hole 56A as a positioning portion for assembling the gear chamber are formed at the same coordinate position, so that they can be produced for transmission cases 3 and 3 'of different sizes. Processing equipment can be shared, thereby reducing costs.

Next, the operation of the unit swing type engine 10 having the above configuration will be described.

In the unit swing type engine 10, a starter button (not shown) or the kick lever 53 is provided.
The engine 1 is started by the operation of
Is rotated, the cooling fan 32 and the generator 33 coaxially mounted on the crankshaft 13 rotate integrally, and at the same time, the rotation of the crankshaft 13 is controlled by the driving pulley 35 of the V-belt type automatic transmission 2, The power is transmitted to the hollow shaft 46 via the V-belt 49 and the driven pulley 44, and the hollow shaft 46 and the clutch inner 45a of the centrifugal clutch 45 fixed thereto are integrally rotated.

When the rotation speed of the crankshaft 13 is low, the centrifugal force acting on the centrifugal weight 37 rotating together with the crankshaft 13 is small, and the centrifugal weight 3
7 remains stationary at the position shown in FIGS. 1 and 2, and at this time, the movable sheave 35b of the drive pulley 35 is also at the position shown in the drawing, and the diameter of the V belt 49 wound around the drive pulley 35 is small. Conversely, the winding diameter of the V-belt 49 on the pulley 44 is kept large, and the rotation of the crankshaft 13 is reduced and transmitted to the hollow shaft 46 and the clutch inner 45 a of the centrifugal clutch 45. As described above, while the rotation speed of the clutch inner 45a of the centrifugal clutch 45 is low and the centrifugal force acting on the clutch inner 45a is equal to or less than a predetermined value, the centrifugal clutch 45 is in the OFF state, and the hollow shaft 46 and the clutch inner 4
The rotation of 5 a is not transmitted to the driven shaft 42, and the hollow shaft 46 and the clutch inner 45 a freely rotate on the driven shaft 42.

Thereafter, when the rotation speed of the crankshaft 13 increases and the centrifugal force acting on the clutch inner 45a exceeds a predetermined value, the centrifugal clutch 45 is turned on and the rotation of the hollow shaft 46 causes the centrifugal clutch 45 to rotate. Driven shaft 4
2 and the driven shaft 42 is rotationally driven. The rotation of the driven shaft 42 is reduced by two stages through a drive gear 50, a gear (not shown) attached to the intermediate shaft, and a driven gear 51 attached to the output shaft 43, and transmitted to the output shaft 43. The shaft 43 and the rear wheel 52 attached to the shaft 43 are driven to rotate, and the scooter-type motorcycle runs.

Although the magnitude of the centrifugal force acting on the centrifugal weight 37 is proportional to the rotation speed of the crankshaft 13, the centrifugal weight 37 has a diameter along the rear surface of the cam plate 36 according to the magnitude of the centrifugal force. In order to move the movable sheave 35b of the drive pulley 35 toward the fixed sheave 35a side by gradually moving outward in the direction of
9 becomes larger, and conversely, the winding diameter of the V belt 49 in the driven pulley 44 becomes smaller. As a result, the speed ratio between the crankshaft 13 and the driven shaft 42 gradually increases,
The rotation of the driven shaft 42 is gradually increased to perform automatic gear shifting.

[0042]

As is apparent from the above description, according to the present invention, a transmission case main body extending from one side of the crankcase of an engine to the rear of the vehicle body is fastened to the transmission case main body by bolts. A transmission case cover forming a belt chamber for accommodating a V-belt type automatic transmission therein, and a gear chamber fastened by bolts to a rear portion of the transmission case main body and accommodating a reduction gear therein are provided inside the belt chamber. As a method of processing a transmission case of a unit swing type engine constituted by a gear chamber cover formed in a plurality of case processing positioning portions used for machining of the transmission case main body,
At least each of a plurality of belt chamber assembly positioning parts used for assembling the transmission case body and the transmission case cover and a plurality of gear chamber assembly positioning parts used for assembling the transmission case body and the gear chamber cover. Since one is formed at the same coordinate position with respect to a plurality of transmission cases having different sizes, it is possible to reduce production costs by sharing production processing equipment for a plurality of transmission cases having different sizes. can get.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a unit swing type engine.

FIG. 2 is a plan sectional view of a four-cycle engine part of the unit swing type engine.

FIG. 3 is a side sectional view of a four-cycle engine portion of the unit swing type engine.

FIG. 4 is an inner view of the transmission case cover.

FIG. 5 is an inner view of a rear portion of a transmission case and a gear chamber cover.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 1a Crankcase 3,3 'Transmission case 3A Transmission case main body 4 Transmission case cover 5,6,8 Bolt 7,7' Gear room cover 10 Unit swing type engine 54A, 54B, 54B 'Knock pin hole (positioning for case processing) Part) 55A, 55B, 55B 'knock pin hole (positioning part for assembling belt chamber) 56A, 56B, 56B' knock pin hole (positioning part for assembling gear chamber) S1 belt chamber S2 gear chamber

Claims (1)

[Claims] 1. A transmission case body extending from one side of a crankcase of an engine to the rear of the vehicle body, and a belt chamber fastened to the transmission case body by bolts and accommodating a V-belt type automatic transmission therein. And a gear chamber cover forming a gear chamber inside the belt chamber, the gear chamber being fastened with bolts to the rear of the transmission case body and containing a reduction gear therein. A method of processing a transmission case, comprising: a plurality of case processing positioning portions used for machining the transmission case body; and a plurality of belt chamber assembly used for assembling the transmission case body and the transmission case cover. At least one of a plurality of positioning portions for assembling the gear chamber used for assembling the positioning portion and the transmission case main body with the gear chamber cover is different in size. Transmission case processing method of a unit swing type engine, characterized in that formed on the same coordinate positions for a plurality of the transmission case that.