JP2831803B2 - Engine balancer device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a balancer device for an engine, and in particular, includes a pair of balancer weights which are distributed and arranged on both sides of a crankshaft and are rotated synchronously with the crankshaft. The present invention relates to an engine balancer device.

2. Description of the Related Art Conventionally, an engine balancer device having a pair of balancer weights has been proposed, for example, in Japanese Utility Model Laid-Open No. 54-72206.

In this balancer device, one balancer weight is integrally attached to a balancer shaft arranged parallel to a crankshaft of an engine, and the other balancer weight is attached to a main shaft of a transmission arranged parallel to the crankshaft. Attached to rotate freely,
The one balancer weight is disposed outside the crankcase relative to the bearing of the balancer shaft, and the other balancer weight is disposed inside the crankcase relative to the bearing of the main shaft.
The balancer shaft, the other balancer weight,
Also, a gear is provided for each of the crankshafts, and these are connected so as to be interlocked with a chain.

The balancer weights are rotated in the opposite direction to the rotation of the crankshaft and synchronously at the same rotational speed to suppress the primary vibration of the engine.

[Problems to be Solved by the Invention] By the way, the following problems remain in the above-mentioned conventional technology.

That is, since the balancer weight provided on the main shaft is disposed on the inner side of the crankcase than the bearing of the main shaft, the distance between the bearings of the main shaft becomes longer, and measures against bending of the main shaft are taken. This is necessary.

To cope with such a problem, it is conceivable to increase the shaft diameter of the main shaft to secure its rigidity, but this is not preferable because it increases the weight of the engine.

Therefore, conventionally, it has been desired to address these inconveniences, and the present invention is intended to solve such a problem that has been left in the past.

[Means for Solving the Problems] The present invention provides an engine balancer device that can effectively solve the above-described problems, and includes a pair of primary balancer weights that are rotated synchronously with the engine crankshaft. And a pair of rotating shafts, each of which is equipped with a balancer weight, and rotatably supported by a bearing provided on the crankcase, wherein one of the pair of rotating shafts is provided. Is constituted by an input shaft of a transmission that is transmitted from the crankshaft via a gear, and the one balancer weight is located outside the crankcase with respect to a bearing that supports the input shaft of the transmission. hand,
The other balancer weight is disposed between the bearing and a clutch disposed on one end side of the input shaft, and the other balancer weight is located on the opposite side to the clutch, and is located on the opposite side of the bearing on the other end supporting the other rotating shaft. It is provided outside the crankcase.

[Operation] In the engine balancer device according to the present invention, by disposing a pair of primary balancer weights outside the crankcase relative to the bearing of the rotating shaft that supports them,
The distance between the bearings of each rotating shaft is reduced, and the diameter of these rotating shafts can be reduced.

In addition, each balancer weight can be arranged approximately symmetrically with respect to the center of the crankshaft, and generation of couple can be effectively suppressed.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes an engine to which the present embodiment is applied (in the illustrated example, a single-cylinder four-cycle engine), a crankcase 2, a cylinder block 3 connected to an upper part of the crankcase 2, and This cylinder block 3
, A head cover 5 mounted on the top of the cylinder head 4, and a carburetor 6 mounted on the cylinder head 4 and communicated with an intake passage formed therein. With
A balancer device 7 according to this embodiment is provided inside the crankcase 2.

Next, the details will be described. A crankshaft 8 is provided at a substantially central portion of the crankcase 2.
As shown in FIG. 2, the crankshaft 8 is rotatably mounted via a pair of bearings 9 and 10 mounted on the crankshaft 8.
, A piston 11 slidably fitted in the cylinder block 3 is connected via a connecting rod 12.

A rotor 13a of a generator 13 is fixed to an end of the crankshaft 8 on a side protruding from the one bearing 9 to the outside of the crankcase 2. Inside the rotor 13a, a rotor 13a is fixed to a side of the crankcase 2. Stator mounted on the inner surface of generator cover 14 to be mounted
13b is inserted to constitute the generator 13.

Furthermore, the other bearing of the crankshaft 8
As shown in FIGS. 1 and 2, a clutch outer 18 of a clutch 17 provided on a balancer shaft 15 and a main shaft 16 to be described later is provided on an end protruding from the crankcase 2 to the outside of the crankcase 2. A primary gear 19 for rotating the motor is fixed.

The balancer shaft 15 is disposed so as to be parallel to the crankshaft 8 as shown in FIGS. 1 and 2, and is provided on the crankcase 2 as shown in FIG. The bearings 20 and 21 are rotatably supported by the bearings 20 and 21, and both ends of the bearings are projected from the bearings 20 and 21 to the outside of the crankcase 2.

At one end of the balancer shaft 15, a spline 15a extending in the axial direction is formed, and the spline 15a fits one balancer weight 22 to the balancer shaft 15 in a state where relative rotation is restricted. And is fixed by a nut 23 screwed to one end of the balancer shaft 15.

Therefore, the one balancer weight 22 is located outside the crankcase 2 of the bearing 20.

A collar 24 is integrally fixed to the other end of the balancer shaft 15 protruding to the opposite side of the crankcase 2 by a nut 25.
A driven gear 26 meshing with the primary gear 19 of the crankshaft 8 is integrally mounted.

Accordingly, the rotation of the crankshaft 8 is transmitted from the primary gear 19 to the balancer shaft 15 via the driven gear 26, and together with the balancer shaft 15,
The one balancer weight 22 is rotated.

As shown in FIG. 1, the main shaft 16 holds the balancer shaft
On the side opposite to 15, it is disposed so as to be parallel to the crankshaft 8, and is rotatably supported by a pair of bearings 27 and 28 attached to the crankcase 2, one end of which is provided. As shown in FIG. 2, it is located inside the crankcase 2 and the other end is connected to the bearing
It is positioned so as to protrude out of the crankcase 2 from 28.

A clutch inner 29 of the clutch 17 is fitted to the other end in a state where relative rotation is restricted by a spline.
29 is integrally fixed by a nut 30.

The clutch outer 18 is disposed so as to surround the clutch inner 29, and the clutch outer 18 is supported on the outer periphery of the protruding end of the main shaft 16 so as to be relatively rotatable. .

Between the clutch inner 29 and the clutch outer 18, a plurality of disc-shaped clutch plates 31 are arranged in a superposed state in the length direction of the main shaft 16, and
These clutch plates 31 are alternately connected to the clutch outer.
The clutch 18 and the clutch inner 29 are engaged around the axis.

Also, the clutch outer 18 and the clutch inner 29
A pusher plate 32 slidably mounted in the main shaft 16 in the axial direction is interposed between the main shaft 16 and the main shaft 16 in the axial direction. Each of the clutch plates 31 is pressed against the clutch inner 29 by the elastic force of the clutch spring 33 and pressed against the clutch inner 31.

As shown in FIG. 2, a driven gear meshed with the primary gear 19 and supported by the main shaft 16 so as to be relatively rotatable is provided on a side of the clutch outer 18 on the side of the crankcase 2. The fixed balancer 34 is fixed, and the other balancer weight 35 is integrally mounted between the driven gear 34 and the clutch outer 18 so as to be clamped.

Therefore, the other balancer weight 35 is located outside the crankcase 2 on the side opposite to the side where the one balancer weight 22 is disposed, and the rotation of the crankshaft 8 causes the rotation of the crankshaft 8. It can be rotated in the opposite direction.

In addition, the primary gear 19, both driven gears 26 and 34
Are set to have the same number of teeth, so that the balancer weights 22 and 35 are
In contrast, it can be rotated in the opposite direction at the same speed as the rotation.

In this embodiment, the balancer shaft 15, the balancer weights 22 and 34, and the driven gears 26 and 33 constitute the balancer device 7.

On the other hand, in the present embodiment, a counter shaft 36 disposed in parallel with the main shaft 16, a transmission gear group 37 provided between the main shaft 16 and the counter shaft 36, and a transmission gear group 37 A plurality of shift forks 38 for selectively operating 37, a guide shaft 39 for guiding the movement of these shift forks 38, a shift drum 40 engaged with each of the shift forks 38 to make the movement, A transmission 42 including a shift shaft 41 for driving the shift drum 40 to rotate is provided in the crankcase 2.

Further, in the present embodiment, another set of balancer devices is provided on the outer peripheral portion of the balancer shaft 15 inside the crankcase 2 and on the portion of the counter shaft 36 located inside the crankcase 2. 43 are provided.

The balancer device 43 includes the balancer shaft 15
A sub-balancer weight 44 mounted on the outer periphery of the sub-balancer weight so as to be relatively rotatable; a driven gear 45 integrally mounted on the sub-balancer weight 44;
A drive gear 46 mounted in a state where relative rotation is restricted to the sub-balancer weight 47 mounted on the inside of the crankcase 2 at an outer periphery near the other end of the counter shaft 36 so as to be relatively rotatable; A drive gear 48 provided integrally with the sub balancer weight 47 and a drive gear 46 mounted on the main shaft 16 so as to be relatively rotatable and provided on the drive gear 46 attached to the crankshaft 8 and a sub balancer weight 47 of the counter shaft 36. And an idle gear 49 that meshes with the drive gear 48.

A portion of the counter shaft 36 to which the sub balancer weight 47 is attached is formed to have an outer diameter larger than an outer diameter of a spline portion with which the transmission gear group 37 is engaged.

This is because, when the sub balancer weight 47 is provided on the countershaft 36, a bending moment acts on the countershaft 36 due to the centrifugal force at the time of rotation of the sub balancer weight 47. By increasing the thickness, the rigidity of the counter shaft 36 is increased, and the counter shaft
This is a procedure taken to promote 36 diameter reduction.

When such a treatment is not performed, it is necessary to attach a spacer or the like to the attachment portion of the sub balancer weight 47 and receive the thrust load of the counter shaft, but in this case, not only the number of parts increases but also This also leads to a decrease in assemblability.

Thus, the engine balancer device 7 of the present embodiment configured as described above has a pair of balancer weights 22.
35 are both disposed outside the crankcase 2, so that their position can be set relatively easily, and the balancer weights 22 and 25 are set to positions substantially point-symmetric with respect to the center of the crankshaft 2. This makes it possible to cancel the couple generated by one balancer weight 22 with respect to the center of the crankshaft 2 by the other balancer weight 35,
The generation of couples is avoided.

Therefore, the primary vibration of the engine 1 is effectively suppressed.

Also, a pair of bearings 20 and 21 that support the balancer shaft 15 and the main shaft 16 and a rotating shaft that supports the balancer weights 22 and 35,
The distance between 28 is reduced, and the rigidity of both shafts 15 and 16 is increased.

Therefore, the diameter of each of the shafts 15 and 16 can be reduced, so that the weight of the engine 1 and the production cost can be reduced.

The various shapes, dimensions, and the like of the components shown in the above-described embodiment are merely examples, and can be variously changed based on the type of engine to be applied, design requirements, and the like.

[Effects of the Invention] As described above, in the engine balancer device according to the present invention, a pair of primary balancer weights that are rotated synchronously with the crankshaft of the engine, and these balancer weights are mounted, respectively. A balancer device comprising: a pair of rotating shafts rotatably supported by bearings provided in a crankcase, wherein one of the pair of rotating shafts is power-transmitted from the crankshaft via a gear. The balancer weight is disposed outside the crankcase with respect to a bearing that supports the input shaft of the transmission and at one end of the bearing and the input shaft. And the other balancer weight is connected to the other rotating shaft on the side opposite to the clutch. It is provided outside the crankcase than the bearing at the other end to be supported, and has the following excellent effects.

Since the pair of balancer weights are both arranged outside the crankcase, the position setting thereof is relatively easy, and these balancer weights are installed at positions substantially point-symmetric with respect to the center of the crankshaft 2. This makes it possible to cancel the couple generated by one balancer weight with respect to the center of the crankshaft by the other balancer weight, thereby preventing the generation of the couple.

Therefore, the primary vibration of the engine can be effectively suppressed, and the engine can be made to have low vibration.

In addition, the distance between a pair of bearings that support the rotating shafts that support the balancer weights can be reduced, thereby increasing the rigidity of these rotating shafts, making it possible to reduce the diameter of each rotating shaft, and reducing the engine weight. And production costs can be reduced.

In addition, because the rotating shaft that supports the balancer weight is also used as the input shaft of the transmission, and one balancer weight is placed by effectively utilizing the space between the clutch and the bearing, it is compact. Can be achieved.

Further, as described above, one balancer weight is arranged between the clutch and the bearing, and the bearing on the side where the clutch originally exists has a strong structure for supporting the clutch. When the balancer weights are arranged close to each other, it is possible to prevent the occurrence of new vibrations and blurs due to the rotation of the balancer weights, and it is excellent in terms of strength.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional side view of a main part of an engine to which the embodiment is applied, and FIG. 2 is a view taken along the line II-II in FIG. It is sectional drawing. 1 ... engine, 2 ... crankcase, 7 ... balancer device, 15 ... balancer shaft, 16 ... main shaft, 19 ... primary gear, 20 ... bearing, 21 ... bearing, 22 ... (one side) A) Balancer weight, 26 ... driven gear, 27 ... bearing, 28 ... bearing, 34 ... driven gear, 35 ... (other) balancer weight.

Claims (1)

(57) [Claims] 1. A pair of primary balancer weights which are rotated synchronously with a crankshaft of an engine, and a pair of these balancer weights respectively mounted thereon and rotatably supported by bearings provided in the crankcase. A balancer device comprising: a rotating shaft, wherein one of the pair of rotating shafts is constituted by an input shaft of a transmission to which power is transmitted from the crankshaft via a gear, and the one balancer weight is Is disposed outside of the crankcase with respect to the bearing supporting the input shaft of the transmission, between the bearing and a clutch disposed on one end side of the input shaft, and the other balancer weight is On the side opposite to the clutch, disposed outside the crankcase than the bearing on the other end supporting the other rotation shaft. Balancer device for an engine according to claim Rukoto.