JP3777896B2 - engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine such as a V-type 2-cylinder engine mounted on, for example, a motorcycle or an outboard motor, and more particularly to an engine in which a speed detection mechanism is installed in an engine case (same as a crankcase). is there.
[0002]
[Prior art]
Conventionally, in an engine mounted on this type of motorcycle or the like, for example, a vertical V-type two-cylinder engine unit, the piston operation of the front and rear cylinders is converted into the rotation operation of the crankshaft via a connecting rod, The rotational force of the shaft is changed to a desired or appropriate speed by a speed change mechanism to obtain a drive output to the rear wheels. The rotation of the crankshaft is transmitted to an intake / exhaust valve through a cam chain whose tension can be adjusted by a cam chain guide to perform intake / exhaust control.
[0003]
Further, the shift of the rotational force of the crankshaft is transmitted to the countershaft of the transmission mechanism via the primary drive gear, and the driveshaft is shifted by selecting the meshing gear of the transmission gear train of the countershaft and the transmission gear train of the driveshaft. Output. Then, power is transmitted to the rear wheel of the vehicle body via a drive chain meshed with a sprocket provided on one end side of the drive shaft.
[0004]
In order to install the speed detection mechanism in such an engine unit, for example, a speed detection rotor is provided on the drive shaft, and the speed sensor is brought close to the rotor so as to face the rotor. The vehicle speed is detected by detecting the rotational speed of the rotor with this speed sensor.
[0005]
[Problems to be solved by the invention]
However, in such a speed detection mechanism in an engine having a conventional structure, a rotor is attached to the end side of the drive shaft to which the sprocket is attached, and a speed sensor is attached to the sprocket cover side corresponding to the attachment position of the rotor. Alternatively, the current situation is that the rotor is attached to the end side of the counter shaft to which the clutch housing is attached, and the speed sensor is attached to the clutch cover side corresponding to the attachment position of the rotor.
[0006]
For this reason, conventionally, the base end of the speed sensor attached to the sprocket cover or the clutch cover is exposed to the outside, and is not only easily damaged by external forces such as rocks jumping during traveling, but also emphasizes the appearance. If it is installed in the model to be concealed, it is necessary to conceal and protect it with another new cover.
[0007]
By the way, when the speed sensor is mounted on the crankcase side and is positioned close to the rotor, the outer diameter of the rotor is increased in consideration of interference with transmission parts assembled in the crankcase. Can not do it.
[0008]
Moreover, because it is required to use an existing speed sensor in common with other models in terms of cost, a rotor is attached to the drive shaft, and the speed sensor is to be attached in close proximity to the rotor. In this case, the length of the speed sensor with respect to the rotor is also restricted, so that the position of the speed sensor is restricted by the outer peripheral surface of the crankcase and the outer peripheral side wall of the rear end of the crankcase close to the rotor.
[0009]
When a speed sensor is to be mounted on the outer peripheral surface of the rear end of the crankcase, especially in a V-type two-cylinder engine, a cam chain adjuster for adjusting the tension of the cam chain provided outside the rear end of the rear cylinder. On the other hand, when the tightening tool is inserted from behind, the tightening tool interferes with the outer peripheral surface of the rear end side of the crankcase, which makes it easy to adjust the cam chain tension with the cam chain adjuster. The problem that it cannot be done arises.
[0010]
The present invention has been made in view of the above-described circumstances, and enables the installation of an existing speed sensor in an engine case without increasing the outer diameter of the rotor, and improves the appearance and improves the external force of the speed sensor. An object of the present invention is to provide an engine that can reliably prevent damage and can easily perform a cam chain tension adjusting operation by a cam chain adjuster.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention has the following configuration.
The present invention relates to a small vehicle engine in which a countershaft and a drive shaft each having a transmission gear train in parallel with a crankshaft are rotatably supported in an engine case. A clutch is provided, and a drive sprocket for transmitting power to the rear wheel is attached to the drive shaft on the drive shaft opposite to the starting clutch on the drive shaft, and the drive shaft on the clutch provided side A speed sensor rotor is attached to the engine, and the sensor rotor is located inside the engine from the starting clutch and is disposed so as to overlap the starting clutch in a side view.
[0012]
Further, in the present invention, the transmission gear train of the engine unit is housed in a pair of engine cases combined so as to be split into right and left parts, and both left and right ends of each shaft are exposed to the outside of the engine case. An engine that is concealed and protected by a sprocket cover and a clutch cover that are detachably attached to each engine case, and a recess recessed forward is formed in a rear wall portion of the engine case, A speed sensor mounting portion for mounting the speed sensor is provided in the recess so as to face the rotor for the speed sensor, and an extension portion extending backward is provided in a portion corresponding to the recess of the clutch cover. The speed sensor can be concealed and protected at the portion.
In the present invention, the engine is a V-type multi-cylinder engine, and the recess of the speed sensor mounting portion is provided from the rear side of a tightening tool used for a cam chain adjuster provided outside the rear end of the rear cylinder of the engine. The insertion operation can be made so as not to interfere with the outer peripheral surface of the rear end side of the engine case.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2 show a motorcycle equipped with an engine according to an embodiment of the present invention, for example, a V-type two-cylinder engine.
[0014]
1 and 2, reference numeral 1 denotes an engine unit mounted on the vehicle body A. The engine unit 1 includes a front cylinder 2A and a rear cylinder 2B that constitute an engine 2, as shown in FIGS.
[0015]
As shown in FIGS. 1 to 4, each of the cylinders 2 </ b> A and 2 </ b> B includes a cylinder housing 3, a piston cylinder 4, and a piston 5, and ignites an air-fuel mixture sucked into an upper combustion chamber of the piston 5 in the piston cylinder 4. Burn with plug 6. The piston 5 is a piston operated by the intake and exhaust processes according to the inlet valve 7 and exhaust valve 8, the piston operation of the piston 5, a crankshaft 21 that outputs a driving force to the power transmission mechanism of the transmission unit 20 to be described later via the connecting rod 9 To communicate.
The intake / exhaust control of the inlet valve 7 and the exhaust valve 8 is performed by rotation of a pair of rocker arms 10 and 11 and a cam 12 (camshaft 13) that alternately rocks the rocker arms 10 and 11.
[0016]
The cam 12 rotates by engaging the cam chain 15 between the sprocket 14 provided on the camshaft 13 and the sprocket 22 assembled to the crankshaft 21, and via the camchain 15, the crankshaft 21. Is transmitted to the camshaft 13.
[0017]
The cam chain 15 is guided and held by a cam chain guide 16 and is maintained by a cam chain tensioner 17 so as to be adjustable to a predetermined tension. In particular, the cam chain tensioner 17 on the rear cylinder 2B side is provided. Is supported by a shaft 18 so as to be capable of rotating, and a tension on the cam chain 15 is adjusted by a cam chain adjuster 19 provided outside the rear end of the cylinder housing 3.
[0018]
The cam chain adjuster 19 includes an adjuster rod 19b urged by a spring 19a in a protruding direction for pressing the cam chain tensioner 17 against the cam chain, and a ratchet mechanism 19c that allows only movement of the adjuster rod 19b in the protruding direction. According to the slack of the cam chain, the adjuster rod 19b is protruded to automatically adjust the tension of the cam chain. The cam chain adjuster 19 needs to be removed from the engine when it is necessary to loosen the cam chain such as disassembling the cylinder head.
In the embodiment, the bolt for attaching the cam chain adjuster 19 to the engine is tightened by the insertion operation from the rear of the tightening tool T. 3, the cam chain adjuster 19 causes the insertion operation shaft P by the tightening tool T to be inclined θ according to the rearward inclination angle α of the cylinder housing 3 of the rear cylinder 2B, as indicated by a two-dot broken line in FIG. Installed.
[0019]
On the other hand, the mission unit 20 of the engine unit 1 is assembled and housed in a pair of left and right crankcases 41 and 42 which are combined so as to be divided into right and left, which will be described later. The one end 21a side of the crank shaft 21 is the starter driven gear 22 of a starter motor driven gear of the starter (not shown) engages is assembled, it is axially supported on one of the crank case 41 side. A primary drive gear 23 is assembled with the cam chain sprocket gear on the other end 21b side of the crankshaft 21 and is pivotally supported on the other crankcase 42 side.
[0020]
The primary drive gear 23 of the crankshaft 21 is meshed with a primary driven gear 25 assembled to the countershaft 24 of the speed change mechanism, and the rotational force of the crankshaft 21 is transmitted to the countershaft 24 via the primary drive gear 23 and the primary driven gear 25. To communicate.
[0021]
One end portion 24a side of the counter shaft 24 is pivotally supported on one crankcase 41 side, and on the other end portion 24b side, together with the primary driven gear 25, a clutch housing 26, a clutch sleeve hub 27, a clutch pressure plate as a starting clutch mechanism. 28 and the clutch release rack 29 are assembled and supported on the other crankcase half 42 side.
The speed change mechanism shifts the rotation output of the engine 2 input via the clutch mechanism and outputs it from the drive shaft 30 by selecting the meshing of the gear train of the drive shaft 30 via the gear train of the counter shaft 24. The output driving force is transmitted to the rear wheel of the vehicle body A through a drive chain 32 that is engaged with and speared on a sprocket 31 assembled on the one end 30a side of the drive shaft 30.
[0022]
The left and right ends 21a, 21b, 24a, 24b and 30a, 30b of the crankshaft 21, countershaft 24 and drive shaft 30 are exposed to the outside from the left and right crankcases 41 and 42, respectively. In addition, each exposed end portion is concealed and protected by a sprocket cover 51 and a clutch cover 52 that are detachably attached to the crankcases 41 and 42, respectively. A clutch release pinion 53 that meshes with the clutch release rack 29 of the mechanism is provided.
[0023]
A speed sensor rotor 33 for speed detection is assembled on the other end 30b side of the drive shaft 30. The rotor 33 is located on the engine inner side than the starting clutch (specifically, Is located on the inner side of the mating surface 60 of the clutch cover 52 and the crankcase), and all or part of the clutch overlaps the starting clutch when viewed from the side.
Further, the rear end outer peripheral surface 42a of the crankcase 42 rear wall corresponding to the rotor 33, in the vehicle width direction outer side position, the portion of the outline L-shape toward the portion of the top surface from the rear, portion (concave recessed forwardly Tokoro) 43 is formed. The recess 43 is formed in a position that does not interfere with the insertion operation shaft P by the tightening tool T of the cam chain adjuster 19 provided outside the rear end of the rear cylinder 2B.
On the wall of the recess 43, a speed sensor 44 is inserted and fixed from the rear to the front, and is attached so as to face the rotor 33 in close proximity.
[0024]
Further, a skirt portion 52a is formed to extend toward a portion where the recess 43 is not formed on the rear end outer peripheral surface 42a of the rear wall of the crankcase 42 at the outer peripheral portion on the rear side of the clutch cover 52. Thus, the attachment base end portion 44a of the speed sensor 44 can be concealed and protected from the outside. When viewed from the right side of the vehicle body, the skirt portion 52a of the clutch cover appears to coincide with the rear end outer peripheral surface 42a of the rear wall portion of the crankcase 42, and the mounting base end portion 44a with the connector of the speed sensor 44 is almost invisible. You can get a well-organized appearance.
[0025]
In the above-described embodiment, the V-type two-cylinder engine has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to a one-cylinder engine or a multi-cylinder engine, and does not depart from the gist of the present invention. Various modifications can be made.
[0026]
【The invention's effect】
As is apparent from the above description, according to the present invention, the entire width of the power unit can be reduced as compared with the case where the sensor rotor is disposed outside the drive sprocket. Further, since the sensor rotor is disposed inside the clutch, the outer diameter of the rotor can be formed in a system, and more accurate speed measurement can be performed. Further, since the sensor rotor is formed so as to be substantially within the outer diameter of the clutch, the engine can be reduced in size.
Further, since the base end portion of the speed sensor is concealed and protected by the skirt portion that is formed integrally with the clutch cover, damage due to external force due to, for example, rocks jumping during traveling can be prevented. Further, the shape of the clutch cover is not affected by the position of the sensor, and the speed sensor is not affected by the clutch cover.
Further, in the V-type multi-cylinder engine, the recess of the sensor mounting portion is against the operation from the rear of the tightening tool used for adjusting the tension of the cam chain adjuster of the cam chain provided outside the rear end of the rear cylinder. Since it has a configuration that does not interfere with the outer peripheral surface of the rear end side of the engine case, it is possible to easily perform the tightening operation of the bolt to which the cam chain adjuster is attached.
[Brief description of the drawings]
FIG. 1 is a right side view showing an embodiment of a motorcycle equipped with an engine according to the present invention, for example, a V-type two-cylinder engine.
FIG. 2 is a left side view of the same.
FIG. 3 is an enlarged sectional view of the engine unit.
4 is a cross-sectional view of the engine unit as seen from the direction of arrows II in FIG.
[Explanation of symbols]
A Body 1 Engine unit 2 Engine 2A Front cylinder 2B Rear cylinder 3 Cylinder housing 4 Piston cylinder 5 Piston 7 Inlet valve 8 Exhaust valve 9 Connecting rod 15 Cam chain 16 Cam chain guide 17 Cam chain tensioner 19 Cam chain adjuster 20 Mission part 21 Crankshaft 21a Crankshaft one end 21b Crankshaft other end 23 Primary drive gear 24 Countershaft 24a Countershaft one end 24b Countershaft other end 25 Primary driven gear 26 Clutch housing 27 Clutch sleeve hub 28 Clutch pressure plate 30 Driveshaft 30a Driveshaft one end Part 30b drive shaft other end part 31 Purokettogiya 32 drive chain 33 speed detection rotor 41 crankcase (engine case)
42 Crankcase (engine case)
42a Rear end peripheral surface of rear wall portion of crankcase 43 recess 44 speed sensor 51 sprocket cover 52 clutch cover 52a skirt portion

Claims (3)

In a small vehicle engine in which a counter shaft and a drive shaft each provided with a transmission gear train in parallel with a crankshaft are rotatably supported in an engine case,
In the counter shaft, a starting clutch is arranged at one end of the shaft,
In the drive shaft, a drive sprocket for transmitting power to the rear wheel is attached to the drive shaft shaft end opposite to the start clutch mounting side, and a speed sensor rotor is mounted to the drive shaft shaft end on the clutch mounting side. Installation,
The engine is characterized in that the sensor rotor is located on the inner side of the engine with respect to the starting clutch and is disposed so as to overlap the starting clutch in a side view. The transmission gear train of the engine unit is housed in a pair of engine cases that are combined so as to be divided into left and right parts, and the left and right ends of each shaft are exposed to the outside of the engine case. An engine that is concealed and protected by a sprocket cover and a clutch cover that are removably attached,
In the rear wall portion of the engine case, a recess that is recessed forward is formed, and in the recess is provided a speed sensor mounting portion that mounts the speed sensor so as to face the rotor for the speed sensor,
2. The engine according to claim 1, wherein an extension portion extending rearward is provided at a portion corresponding to the recess of the clutch cover, and the speed sensor is concealed and protected by the extension portion. The engine is a V-type multi-cylinder engine, and the recess of the speed sensor mounting portion is formed with respect to the insertion operation from the rear of the tightening tool used for the cam chain adjuster provided outside the rear end of the rear cylinder of the engine. The engine according to claim 2, wherein the engine case does not interfere with the outer peripheral surface of the rear end side of the engine case.

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