JPH0245506Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a drive pulley in which a dog clutch is arranged at a distance from the end face in the axial direction.

For example, in a small motorcycle, a drive pulley is attached to the end of the engine crankshaft, a V-belt is wound around this drive pulley and a variable diameter driven pulley attached to the transmission shaft, and the V-belt is wound around the drive pulley and the axle that meshes with the transmission shaft. An automatic transmission mechanism that transmits power is adopted.

A dog clutch that engages with a helical gear on the starter shaft for starting the engine is placed spaced apart on the axial end surface side of the drive pulley, while a dog flange that engages with the dog clutch is placed adjacent to the drive pulley at the end of the crankshaft. I was wearing it.

Conventionally, a dog flange separate from the drive pulley was required.

The present invention eliminates the conventional separate dog flange and directly engages the dog clutch and drive pulley.Therefore, the number of parts and costs are reduced, and the drive pulley is advantageous in terms of machining. It was created for the purpose of providing.

In order to achieve such an objective, the present invention provides a drive pulley at the end of the drive shaft of an internal combustion engine mounted on a small passenger car, and connects this drive pulley and a driven pulley provided on the driven shaft with a V-belt. In the V-belt type power transmission device in which a dog clutch is arranged at a distance on the end face side of the drive shaft, the half of the drive pulley is formed of a press-formed steel plate, and the half of the drive pulley is radially inner than the contact surface of the V-belt. A dog is formed by punching in the portion, and the dog is composed of a sheared surface that engages with the dog clutch, and an inclined surface that is continuous with the sheared surface, and a recess is formed on the back side of the dog. shall be.

A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an exploded plan view of the power unit, showing a crankshaft 5 connected via a connecting rod 4 to a piston 3 sliding inside a cylinder 2 of an engine 1.
One end protrudes into the transmission case 6, a drive pulley 7 is fixed to the end of the crankshaft 5, and a V-belt 10 is wound around the drive pulley 7 and driven pulley 12. The driven pulley 12 is loosely coupled to a transmission shaft 11 that is supported horizontally on the rear part of the transmission case 6, and the driven pulley 12 consists of a fixed pulley half 13 and a movable pulley half 15.
A holder plate 17 is fixed to the tip of the boss portion 14 of the fixed pulley half 13 which is slidably fitted on the outside in only the axial direction of the pulley 5, and a coil spring 18 is installed between the holder plate 17 and the movable pulley half 15. It has been reduced.

The clutch weight 22 is pivotally supported on the holder plate 17 by a pin 21, and the transmission shaft 11
A centrifugal clutch 20 is configured by a clutch outer 23 fixed to one end, and a pinion 2 formed near the other end of the transmission shaft 11.
4 is meshed with a gear 26 fixed to an axle 25.

On the other hand, a starter jack shaft 31 is supported horizontally in the intermediate part of the transmission case 6 near the crankshaft 5, and a sector gear 32 fixed to the starter shaft 31 is in helical gear engagement with a pinion 36 formed on a clutch shaft 35. A return coil spring 33 is stretched between the kick shaft 31 and a boss portion 61 protruding from the inner wall of the transmission case 6.

Further, the clutch shaft 35 is connected to the crankshaft 5.
Cantilevered on the transmission case 6 concentrically with the
A drum-shaped dog clutch 37 is fixed to the tip of the clutch shaft 35, and a return coil spring 39 is installed between the dog clutch 37 and a boss portion 62 protruding from the inner wall of the transmission case 6 in front of the dog clutch 37. There is.

In the present invention, as shown in an enlarged view in FIG. 2, the half body 8 of the drive pulley 7 facing the dogs 38 of the dog clutch 37 is formed of a press-formed steel plate, and the central part is formed into a flat plate part 81. When forming the half body 8 by press-forming the outer peripheral part from a steel plate into the tapered part 82, the dog 3 is attached to the flat plate part 81.
Dogs 83... to be fitted with 8... were formed by half punching in a radial manner. This dog 83 is located on the inner diameter side of the V-belt 10 abutting surface of the pulley half 8. A front view of this steel plate pulley half 8 is shown in FIG. 3, and a sectional view of the dogs 83 is shown in FIG. 4, respectively.

As shown in FIG. 4, the dogs 83 of the steel plate pulley half 8 are punched out from the flat plate part 81 by approximately half of its wall thickness, and the sheared end surfaces 84 facing the outer surface and the inclined surfaces 85 are uniform. The dogs 83 all face in the same direction and constitute an engagement surface and a relief surface, respectively, and thus constitute a one-way clutch together with the dog clutch 37. Further, a recess is formed on the back side of the dog 83.

Then, the steel plate pulley half 8 is overlapped with the other pulley half 9 and spline-fitted to the end of the crankshaft 5, and the washer 51 is interposed and the nut 52 is fitted.
is fastened to the end of the shaft 5, thereby attaching the drive pulley 7.

Next, the connection and disconnection of the dog clutch 37 will be described.

First, a kick pedal (both not shown) is connected to the end of the kick shaft 31 protruding from the outer surface of the transmission case 6 via a crank arm, as is known in the art.

By depressing this kick pedal, the kick shaft 31 rotates, and the clutch shaft 35, which is integrated with the pinion 36 that meshes with the sector gear 32, is driven to rotate, and the helical meshing of the sector gear 32 and the pinion 36 causes the clutch shaft 35 to have a return spring. The crankshaft 5 resists the spring force of 39.
move forward in the direction, and each dog 8 of the dog clutch 37
3 engage with the engagement surfaces 84 of the respective dogs 83 integrally formed on the steel plate pulley half 8 of the drive pulley 7, and rotationally drive the crankshaft 5 integral with the drive pulley 7, thus causing the engine 1 to rotate. is started.

After starting engine 1, return spring 3
9, the clutch shaft 35 is retracted and returned to its initial position, thus releasing the clutch.

Since there is pulsation in the engine in the above,
The rotation of the V-belt is not constant speed (or constant acceleration) but is constantly accelerated or decelerated, and heat generation occurs due to friction on the contact surface between the belt and the pulley. However, in the present invention, the V-belt is in contact with the drive pulley half A dog is formed on the inner diameter side than the surface, and a recess is formed on the back side of this dog, so the recess creates agitation in the air layer near the drive shaft surrounded by the V-belt, allowing the heat to escape. , it is possible to prevent a temperature rise in this area. In addition, in a structure in which the power of the drive shaft is transmitted to the driven shaft by a V-belt, the V-belt is wound around with considerable tension, so it is desirable to secure a sufficient contact area. Since it is formed on the inner diameter side of the V-belt contact surface of the body, the dog is not located on the V-belt contact surface, and a sufficient contact area of the V-belt can be secured. Furthermore, according to the present invention, the drive pulley 7
The half body 8 of the steel plate pulley half body 8 is formed of a press-formed steel plate, and the outer surface of the steel plate pulley half body 8 is provided with a dog 83 which engages with the dog clutch 37 by punching.
Since the dog 83...
can be formed simultaneously with the press forming of the steel plate pulley half body 8, so that the processing time can also be shortened. The inclined surface 85 makes it easy to disengage the dog clutch on the crankshaft side and the crank on the pulley side.

As described above, the drive pulley of the present invention has many advantages.

[Brief explanation of the drawing]

Fig. 1 is a developed plan view of a power unit implementing the present invention, Fig. 2 is a partially cutaway plan view showing an enlarged view of its main parts, Fig. 3 is a front view of a steel plate pulley half, and Fig. 4 is a sectional view taken along the line in FIG. In the drawing, 5 is the crankshaft, 7 is the drive pulley, 8 is the steel plate pulley half, 83 is the dog, 10 is the V-belt, 11 is the transmission shaft, 1
2 is a driven pulley, 25 is an axle, 31 is a starter shaft, 32 is a sector gear thereof, 35 is a clutch shaft, 36 is a pinion, 37 is a dog clutch, 38 is a dog, and 39 is a return spring.

Claims (1)

[Scope of utility model registration request] A drive pulley is provided at the end of the drive shaft of an internal combustion engine mounted on a small passenger car, this drive pulley and a driven pulley provided on the driven shaft are connected by a V-belt, and a dog clutch is arranged at a distance on the end face side of the drive shaft. In the V-belt type power transmission device,
A half of the drive pulley is formed from a press-formed steel plate, and a dog is formed by punching on a portion of the half on the inner diameter side of the contact surface of the V-belt,
A drive pulley characterized in that the dog comprises a sheared surface that engages with the dog clutch and an inclined surface continuous to the sheared surface, and a recess is formed on the back side of the dog.