JPH09329193A - Backlash adjusting method in balancer device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely perform the backlash adjustment among a balancer driving gear, an idle gear and a balancer gear. SOLUTION: A line segment OQ connecting a crank shaft 3 and an idle shaft 11 comprising a decentering part 11b, and a line segment QP connecting the idle shaft 11 and a balancer shaft 10 comprising a decentering part 10b, are arranged to be almost squared. A backlash between an idle gear 55 and a balancer driving gear 51, and that between the idle gear 55 and a balancer gear 60 are setted to be higher than the optical values. Then the idle shaft 11 is rotated in the direction of an arrow (c) to move the idle gear 55 in the direction of an arrow (e), for adjusting the backlash between the idle gear 55 and the blancer driving gear 51, and then the balancer shaft 10 is rotated in the direction of an arrow (d) to move the balancer gear 50 in the direction of an arrow (f), for adjusting the backlash between the balancer gear 60 and the idle gear 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer weight rotatably supported on a balancer shaft provided with a balancer gear, the balancer gear being provided on a crankshaft, and an idle gear rotatably supported on an idle shaft. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer device for an engine driven via a motor, and particularly to a backlash adjusting method thereof.

[0002]

2. Description of the Related Art A balancer device for such an engine is already known from Japanese Patent Laid-Open No. 4-277349.

[0003]

By the way, when the rotation of the balancer drive gear of the crankshaft is transmitted to the balancer gear via the idle gear, the backlash between the idle gear and the balancer drive gear and the gap between the idle gear and the balancer gear. It is necessary to adjust the backlash and the backlash, but the adjustment of one backlash changes the other backlash, so the adjustment was extremely troublesome. Since the idle gear meshes with both the balancer drive gear and the balancer gear, when the idle gear is moved to adjust the backlash between the idler gear and the balancer drive gear, for example, the idle gear interferes with the balancer gear. There is a problem that the adjustment becomes difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to easily and surely adjust the backlash between the balancer drive gear, the idle gear and the balancer gear.

[0005]

In order to achieve the above object, the invention described in claim 1 is an idle gear in which a balancer drive gear provided on a crankshaft is rotatably supported on an eccentric portion of an idle shaft. And the idle gear is meshed with the balancer gear provided on the balancer weight rotatably supported on the eccentric part of the balancer shaft, and the line segment connecting the crankshaft and the idle shaft to the idle shaft and the balancer shaft. In an engine balancer device that intersects the connecting line segments at a substantially right angle, by rotating the idle shaft and balancer shaft, the distance between the idle gear and the balancer drive gear is set larger than the optimal backlash distance, and Gears and balancers The first step is to set the distance between the gears larger than the optimal backlash distance, and by rotating the idle shaft, the distance between the idle gear and the balancer drive gear is optimized while reducing the distance between the idle gear and the balancer gear. The method is characterized by including a second step of adjusting the backlash distance and a third step of adjusting the distance between the idle gear and the balancer gear to an optimum backlash distance by rotating the balancer shaft.

According to the invention described in claim 2, in addition to the structure of claim 1, the balancer shaft and the idle shaft for rotating the balancer shaft and the idle shaft at one end of the balancer shaft and the idle shaft extending from the casing to the outside. It is characterized in that a groove with which a tool is engaged is formed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 8 show an embodiment of the present invention. FIG. 1 is a side view of an engine mounted on a motorcycle, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3-3 in FIG.
4 is a sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a sectional view taken along line 5-6 of FIG. 4, FIG. 6 is a sectional view taken along line 6-6 of FIG. 4, and FIG. An enlarged view and FIG. 8 are explanatory views of the operation.

As shown in FIG. 1, an in-line four-cylinder engine E supported on a vehicle body frame 1 of a motorcycle by three bolts 2 has a crankshaft 3 arranged in the vehicle body left-right direction and a cylinder axis L. ₁ is arranged inclining to the upper front of the vehicle body. The casing of the engine E includes an upper casing 4 that constitutes the upper half of the crankcase, an upper half of the mission case and the cylinder block, and a lower casing 5 that constitutes the lower half of the crankcase and the lower half of the mission case. And a cylinder head 6 connected to the upper end of the cylinder block of the upper casing 4.
And a head cover 7 connected to the upper end of the cylinder head 6 and an oil pan 8 connected to the lower surface of the lower casing 5.

The engine E includes a secondary balancer device for reducing secondary vibration. The secondary balancer device includes a front balancer Bf and a rear balancer Br,
The front balancer Bf is provided with a front balancer shaft 9 arranged below the crankshaft 3 and slightly forward of the vehicle body, and the rear balancer Br is located above the crankshaft 3 and slightly rearward of the vehicle body. The balancer shaft 10 and the idle shaft 11 arranged below the rear balancer shaft 10 are provided. The front balancer shaft 9 and the rear balancer shaft 10 are disposed at substantially symmetric positions with respect to the crankshaft 3. The transmission housed in the rear portion of the upper casing 4 and the lower casing 5 includes a main shaft 12 located behind the crankshaft 3 and a counter shaft 13 arranged behind the main shaft 12.

As shown in FIGS. 2 and 3, the first to fourth cylinders 21 _{1 to} 21 ₄ formed in the upper casing 4 are shown.
The first to fourth piston 22 _{1-22 4} respectively fitted slidably. The crankshaft 3 includes first to fifth journal portions 23 ₁ to 23 ₅ and _first to fourth pin portions 2 provided between the _first to _fifth journal portions 23 ₁ to 23 _5.
4 _{1 to} 24 ₄ . First to fifth journal section 23
_{1-23 5,} first through formed in the upper casing 4
Fifth journal support portions 25 _{1 to} 25 ₅ and first to fifth journal support portions 26 ₁ to 26 formed on the lower casing 5.
₅ is rotatably supported by the first to fourth pin portions 24 _{1 to} 24 ₄ and the first to fourth pistons 22 _{1 to} 22.
₄ is the first to fourth connecting rods 27 _{1 to} 27 ₄
Connected by

[0012] The first to fifth journal supporting part 26 _{1-26 5} of the lower casing 5, the first upper casing 4
The fifth journal support portions 25 _{1 to} 25 ₅ include five front casing fastening bolts 14 arranged in front of the crankshaft 3 and five rear casing fastening bolts arranged behind the crankshaft 3. The fastening bolts 15 are integrally connected to each other, and the rigidity is increased by the fastening force at that time.

That is, the lower casing 5 supporting the front balancer shaft 9 has a longitudinal elastic modulus (Young's modulus) higher than that of the aluminum alloy which is the material of the lower casing 5.
The front casing tightening bolts 14 and the rear casing tightening bolts 15 made of high steel are fastened, so that the rigidity of the front balancer support portion of the lower casing 5 is increased.

The cylinder head 6 has cylinders 21 ₁ ...
21 ₄ are formed combustion chambers 28 in response to the intake port 6 ₁ connected to the combustion chamber 28, ₆₁ and the exhaust port 6 _2, 6 ₂ to the intake valves 29, 29 and exhaust valves 30, 30 are provided Can be The intake valves 29, 29 and the exhaust valves 30, 30 are driven by an intake camshaft 31 and an exhaust camshaft 32 supported on a connection surface between the cylinder head 6 and a camshaft holder (not shown).

A drive sprocket 33 provided on the right end of the crankshaft 3 and a timing chain 34 for transmitting the rotation of the drive sprocket 33 to the intake camshaft 31 and the exhaust camshaft 32 are housed on the right end surface of the engine E. The timing chain chamber 35 is provided, and a part of the opening to the outside is covered by the timing chain chamber cover 36. An AC generator 37 is provided at the left end of the crankshaft 3, and the outside thereof is covered with an AC generator cover 38.

As shown in FIGS. 3 to 5, the third journal portion 23 ₃ and the fourth journal portion 2 of the crankshaft 3 are shown.
The third formed in the upper casing ₄ to support 34
Journal support 25 ₃ and fourth journal support 25
Between the _four , both right and left ends of the idle shaft 11 of the rear balancer Br are installed. Also over the upper surface of the upper casing 4 from the rear surface of the cylinder block, the casing raised portion 41 is provided by causing extend outwardly of the third journal supporting portion 25 ₃ and the fourth journal supporting portion 25 ₄ from the outer wall of the upper casing 4 .

The casing ridge portion 41 is provided with a ceiling wall portion 41d which covers the upper surface and the rear surface thereof, and a cylinder side wall portion 41e which is connected to the front of the ceiling wall portion 41d and constitutes a side wall of the third cylinder 21 ₃ . 3 Journal support section 2
5 ₃ , the fourth journal support portion 25 ₄ , the ceiling wall portion 41d, and the cylinder side wall portion 41e constitute a highly rigid box structure in which only the lower surface is open. The left and right ends of the rear balancer shaft 10 of the rear balancer Br are installed on the third journal support portion 25 ₃ and the fourth journal support portion 25 ₄ , which form the left and right side walls of the casing raised portion 41.

The rear balancer shaft 10, supporting hole 4 made of a through hole formed in the fourth journal supporting portion 25 ₄
1b and a support hole 41a formed of a blind hole formed in the third journal support portion 25 ₃ and inserted from the support hole 41b side, and fixed by a fixing member 42 at an end portion protruding from the fourth journal support portion 25 ₄ to the outside. To be done. As will be described later, the rear balancer shaft 10 is composed of an eccentric shaft, and the phase of the eccentric portion 10b can be adjusted by engaging a tool with a groove 10a formed at the right end of the rear balancer shaft and rotating the tool. . After the adjustment is completed, the fixing member 42 for fixing the rear balancer shaft 10 so as not to rotate and not to move in the axial direction is formed in a substantially J-shape, and the split groove 42 a holds the right end of the rear balancer shaft 10 and bolts 43. After tightening with, bolt 44
The fourth journal support portion 25 ₄ of the casing ridge 41
Fixed to.

The idle shaft 11 has a support hole 25b formed of a through hole formed in the fourth journal support portion 25 ₄ and a support hole 25a formed of a through hole formed in the third journal support portion 25 ₃ in the fourth journal support portion. It is inserted from the side of 25 ₄ and is fixed by a fixing member 45 and bolts 46 and 47 at the end portion that penetrates the third journal support portion 25 ₃ . The right end of the idle shaft 11 are axially positioned by washers 49 with bolts 48 are secured to the fourth journal supporting portion 25 _4. The idle shaft 11 is also formed of an eccentric shaft, and the phase of the eccentric portion 11b can be adjusted by engaging and rotating a tool in a groove 11a formed at the right end before fixing the idle shaft.

The fourth journal portion 2 of the crankshaft 3
The outer periphery of the 3 ₄ balancer portion 50 adjacent to the left side, the balancer drive gear 51 is integrally formed. Ball bearings 53, 53 are axially positioned on the outer periphery of the eccentric portion 11b of the idle shaft 11 via a collar 52, and the idle gear 55 is detachably supported on the ball bearings 53, 53 via a clip 54. Meshes with the balancer drive gear 51.

As can be seen by referring also to FIG.
A rear balancer weight 58 is rotatably supported on the outer periphery of the eccentric portion 10b of the rear balancer shaft 10 via a first needle bearing 56 and a second needle bearing 57. The rear balancer weight 58 includes a weight portion 58a and a cylindrical shaft portion 58b.
8b is supported by a plurality of damper rubbers 59.
Mesh with. The left and right ends of the rear balancer weight 58 and the third journal support portion 25 of the casing raised portion 41
Between the _third and fourth journal supporting portion 25 _4, the first thrust washer 61 and the second thrust washer 62 is disposed, respectively. Weight portion 58a of the rear balancer weights 58, to avoid interference between the third big end of the connecting rod 27 _3, a third casing raised portion 41
It is disposed adjacent to the journal supporting portion 25 _3.

The first thrust washer 6 disposed between the casing ridge 41 and the third journal support portion 25 _3.
1 is provided with an annular cylindrical holding portion 61b extending toward the rear balancer weight 58 on the outer periphery of the main body 61a, and the third journal supporting portion 25 is provided on the left side surface of the main body 61a.
₃ to support the thrust force between the thrust washer bearing surface f ₁ of the supporting thrust force between the retainer 56a at the left end and the first needle bearing 56 of the rear balancer weight 58 on the right side surface of the main body portion 61a Further, the inner peripheral surface of the cylindrical holding portion 61b engages with the outer peripheral surface on the left end of the rear balancer weight 58, thereby positioning the first thrust washer 61 itself in the radial direction with respect to the rear balancer weight 58. ing.

On the other hand, the second thrust washer 62 arranged between the casing ridge 41 and the fourth journal support portion 25 ₄ has an annular tubular shape extending toward the rear balancer weight 58 on the inner circumference of the main body 62a. The holding portion 62b is provided, and the right side surface of the main body portion 62a supports the thrust force between the thrust washer supporting surface f ₂ of the fourth journal support portion 25 ₄ and the rear balancer weight 58 is provided on the left side surface of the main body portion 62a. Thrust force between the right end part of the second needle bearing 57 and the right end part of the rear balancer gear 60, and the left end face of the cylindrical holding part 62b supports the thrust force between the retainer 57a of the second needle bearing 57 and the cylindrical shape. By engaging the outer peripheral surface of the holding portion 62b with the inner peripheral surface of the right end of the rear balancer weight 58, the second thrust washer 62 itself is moved to the rear balancer weight 5. It is adapted to position in a radial direction relative to.

As is apparent from a comparison of the shapes of the first thrust washer 61 and the second thrust washer 62, the cylindrical holding portion 61b of the first thrust washer 61 is replaced by the main body portion 6
Since it is formed on the outer periphery of 1a, the cylindrical holding portion 61 is formed.
The first needle bearing 56 can be moved to the main body 61a side without interfering with b. As a result, the axial center line A of the first needle bearing 56 is made closer to the center line B passing through the center of gravity of the weight portion 58a of the rear balancer weight 58, and the offset amount α between the center lines A and B is minimized. Can be suppressed. Thus, the unbalanced load acting on the first needle bearing 56 is reduced, so that a small-capacity first needle bearing 56 can be used, and the durability can be improved.

When the rear balancer weight 58 is assembled into the casing raised portion 41, the rear balancer weight 58, the rear balancer gear 60, and the damper rubber 5 are attached.
9, a sub-assembly of the first needle bearing 56, the second needle bearing 57, the first thrust washer 61 and the second thrust washer 62 is assembled together. In a state where the sub-assembly is assembled at the regular assembly position shown in FIG. 4, the first thrust washer 61 and the second thrust washer 62 are attached to the third journal support portion 25 ₃ and the fourth journal support portion 25 of the casing raised portion 41. _It comes into contact with ₄ to prevent it from falling off. However, while inserting the sub-assembly from the opening of the upper casing 4 to the regular mounting position, as shown in FIG. 6, the third journal support 25 ₃ and the fourth journal support 25 ₄ located on both sides of the sub-assembly are inserted. The distance D ₁ between the facing surfaces of the third journal support portion 25 _{3 and the} fourth journal support portion 25 _{4 at the} regular mounting position is D ₂ (between f ₁ and f ₂ for the sake of weight reduction). Since the distance is set larger than the distance), the first thrust washer 61 and the second thrust washer 62 easily fall off from the rear balancer weight 58, which causes a problem that workability is deteriorated. In particular, since the subassembly is assembled in the deepest part of the casing raised portion 41, it is difficult for the operator to enter and the work is difficult.

Therefore, in this embodiment, FIG. 3, FIG. 4 and FIG.
As shown in, the opposed surface of the third journal supporting portion 25 ₃ and the fourth journal supporting portion 25 _4, from said opening of the upper casing 4 thrust washer bearing surface f _1, f ₂
Thrust washer guide surfaces f ₃ and f ₄ are provided so as to be continuous with the thrust washer guide surfaces f ₃ and f ₄ . The left thrust washer support surface f ₁ and the slide guide surface f ₃ are formed flush with each other, and the right thrust washer support surface f ₂ and the thrust washer guide surface f ₄ are formed flush with each other. The distance between the thrust washer supporting surfaces f ₁ and f ₂ and the distance between the pair of opposing thrust guide surfaces f ₃ and f ₄ are both equal to D ₂ .

Thus, when the sub-assembly of the rear balancer weight 58 is inserted into the casing raised portion 41 at the assembling position, the thrust washer guide surfaces f ₃ , f ₄ starting from the opening of the upper casing 4 are attached. With the first thrust washer 61 and the second thrust washer 62 at both ends of the subassembly in contact with each other, the subassembly is slid and inserted into the mounting position in the casing raised portion 41. Thereby, the first thrust washer 61
The second thrust washer 62 is guided to the assembling position where it abuts the left and right thrust washer supporting surfaces f ₁ and f ₂ without coming off from the rear balancer weight 58, so that the assembling workability is greatly improved.

As is apparent from FIGS. 3 to 6, an arcuate rib 63 is projected from the bottom of the casing ridge 41, and the fourth journal support portion 25 _{4 is formed} so that the rib 63 can be seen. A circular opening 41c that can be closed by a plug 64 (see FIG. 4) is formed in the. A part of the rear balancer gear 60 and the phase alignment mark 63a of the rib 63 are visible through the opening 41c, and the rear balancer gear 60 is rotated by inserting a finger through the opening 41c to perform the phase alignment engraved on one tooth. The mark 60a (see FIG. 5) is provided on the rib 6
3 by opposing the phase matching mark 63a.
The phase of the rear balancer gear 60 can be adjusted at the time of assembling the rear balancer Br described later.

When the subassembly is inserted into the casing ridge 41 for assembly, the rear balancer gear 60 abuts against the rib 63 and is roughly positioned as shown in FIGS. 3 and 6, so that the rear balancer weight 5
8 is prevented from dropping to the bottom of the casing raised portion 41, and the assembling work is facilitated.

As shown in FIGS. 3 and 4, the front balancer shaft 9 of the front balancer Bf is installed between the third journal support portion 26 ₃ and the fourth journal support portion 26 ₄ of the lower casing 5. , A first needle bearing 65, a second needle bearing 66 on the outer periphery thereof, a front balancer weight 67 including a weight portion 67a and a cylinder shaft portion 67b, a first thrust washer 68, a second thrust washer 69, The damper rubber 70 and the front balancer gear 71 that meshes with the balancer drive gear 51 are supported. The front balancer shaft 9 includes the fixing member 72 and the bolt 7.
It is fixed to the lower casing 5 by 3,74.

As is apparent from FIG. 4, the front balancer Bf has a structure symmetrical to the rear balancer Br with respect to the crankshaft 3 except that it does not include members corresponding to the idle shaft 11 and the idle gear 55. Therefore, the description of the overlapping structure is omitted. However, the front balancer Bf is arranged at a position relatively shallow from the opening of the lower casing 5, and since it does not have a member corresponding to the idle gear 55, it is easy to assemble and adjust the phase. The components corresponding to the thrust washer guide surfaces f ₃ and f ₄ of Br or the components corresponding to the rib 63 are not required.

In FIG. 4, since the tubular holding portion 68b of the first thrust washer 68 of the front balancer Bf is formed on the outer periphery of the main body portion 68a, the tubular holding portion 6 is formed.
The first needle bearing 65 is moved toward the main body 68a without interfering with the first needle bearing 6b.
5 can be made closer to the center line of the weight portion 67a of the front balancer weight 67. Thus, similarly to the above-described rear balancer Br, the load due to the unbalanced load acting on the first needle bearing 65 of the front balancer Bf can be reduced.

Thus, the number of teeth of the rear balancer gear 60 and the number of teeth of the front balancer gear 71 are both set to one half of the number of teeth of the balancer drive gear 51 provided on the crankshaft 3. Therefore, the rear balancer gear 60 rotates in the same direction as the crankshaft 3 at twice the rotation speed of the crankshaft 3, and the front balancer gear 71 moves at the same rotation speed as the crankshaft 3 at twice the crankshaft 3. It rotates in the opposite direction and reduces the secondary vibration of the engine E as is well known.

In FIG. 3, in order to effectively reduce the vibration of the engine E, it is desirable that the front balancer shaft 9 and the rear balancer shaft 10 are symmetrically arranged with the crankshaft 3 as the center. The distance between the cylinder axis L ₁ and the front balancer shaft 9 is d ₁ , the distance between the cylinder axis L ₁ and the rear balancer shaft 10 is d _2, and the cylinder axis L _{1 of the} front balancer shaft 9 and the rear balancer shaft 10.
When the distance direction along the d _3, the distance d ₁ and distance d
It is desirable to set ₂ to be equal and to set the distance d ₃ to be approximately equal to the length of the connecting rods 27 _{1 to} 27 ₄ .

By arranging the front balancer shaft 9 in the front lower part of the crankshaft 3 and the rear balancer shaft 10 in the upper rear part of the crankshaft 3, the above conditions can be satisfied relatively easily. The rear balancer shaft 10 is used as a space for arranging various auxiliary devices (for example, the air cleaner 16 and the fuel tank 17 shown in FIG. 1) behind the cylinders 21 _{1 to} 21 ₄ that tilt forward and upward. There is a risk of interference with the equipment. However, in this embodiment, since the minimum casing ridge 41 is provided on the upper surface of the upper casing 4 and the rear balancer shaft 10 is housed therein, the space behind the cylinders 21 _{1 to} 21 ₄ is maximized. It is possible to secure it and avoid interference with auxiliary devices. Further, by disposing the idle shaft 11 at the rear of the rear balancer shaft 10 instead of at the front thereof, it is possible to secure a larger space behind the cylinders 21 _{1 to} 21 ₄ .

As is apparent from FIG. 4, the crank shuff
Third journal part 23 of G3_ThreeAnd the fourth journal part 2
Three_FourJournal of upper casing 4 that supports
Support part 25_ThreeAnd the fourth journal supporter 25_FourTo ryaba
A lancer shaft 10 is supported, and the third jar
Null part 23_ThreeAnd the fourth journal section 23_FourB supporting
Third journal support 26 of casing 5_ThreeAnd the fourth
Journal support 26 _FourTo front balancer shaft
9 is supported. Suppose the balancer shafts 9, 10
When supported on the outer wall of the casings 4 and 5, the balancer chassis
To counter the centrifugal force acting on the shafts 9,10.
Thing 4 and 5 need to be reinforced and the weight increases,
In order to support the crankshaft 3 as in this embodiment, a high rigidity
Journal supporter 25_Three, 25_Four, 26_Three,
26_FourTo support the balancer shafts 9 and 10
If this is the case, the casings 4 and 5 do not need to be reinforced, reducing the weight.
Reduced.

[0037] In particular, the journal supporting part 26 _{1-26 5} journal supporting portion 25 ₁ to 25 ₅ and the lower casing 5 of the upper casing 4, a longitudinal elastic modulus than aluminum alloy which is the material of the upper casing 4 (Young Since the coupling rigidity is increased by the tightening force of the front tightening bolts 14 and the rear tightening bolts 15 made of steel having a high ratio, the support of the front balancer shaft 9 and the rear balancer shaft 10 which are supported by them is supported. The rigidity is also improved. As a result, the vibrating force of the front balancer shaft 9 and the rear balancer shaft 10 (vibration suppression force for suppressing the vibration of the crankshaft 9) effectively acts, and the vibration of the entire engine E can be minimized. In particular, since the rear balancer shaft 10 is supported by the casing raised portion 41 having a box structure with only the lower surface opened, and the rear balancer supporting portion is located near the fastening portion of the rear tightening bolts 15. Rigidity can be secured.

Next, the assembling of the rear balancer Br and the front balancer Bf having the above-mentioned structure and the removal of the backlash will be described.

The rear balancer Br is assembled by rear balancer weight 58, rear balancer gear 60, damper rubber 59 ..., First needle bearing 56, Second needle with upper casing 4 fixed with its opening facing upward. As described above, the subassembly in which the bearing 57, the first thrust washer 61, and the second thrust washer 62 are temporarily assembled is inserted into the first washer 61 and the second thrust washer 62 from the opening of the upper casing 4 as described above. ₃ , f
Insert into the casing ridge 41 while guiding it to ₄ . Subsequently, by inserting the tip of the rear balancer shaft 10 from the fourth journal supporting portion 25 ₄ of the support hole 41b of the casing ridges 41, the support hole 41a of the third journal supporting portion 25 ₃ by penetrating the interior of the subassembly Lock.

Next, the ball bearings 53,
The idle gear 55 assembled with the 53 is meshed with the rear balancer gear 60 is inserted from the opening portion of the upper casing 4, a support hole 25b of the fourth journal supporting portion 25 ₄ of the upper casing 4 of the tip of the idle shaft 11 in this state From the ball bearings 53, 53
And the collar 52 is penetrated. At this time, the idle gear 55 is retracted to the position shown by the chain line in FIG. When the idle gear 55 is at the retracted position, the meshing relationship between the idle gear 55 and the rear balancer gear 60 is maintained.

Next, the opening 41c of the casing raised portion 41
To rotate the rear balancer gear 60,
The phase alignment mark 60a faces the phase alignment mark 63a of the rib 63. While fitting the journal portion 23 _{1-23 5} of the crank shaft 3 to the journal supporting part 25 ₁ to 25 ₅ of the upper casing 4 in this state,
Since the idle gear 55 is retracted to the chain line position as described above, the balancer drive gear 5 of the crankshaft 3
1 does not mesh with the idle gear 55. Then, the crankshaft 3 is rotated to, for example, the first pin portion 24 ₁
Then, the fourth pin portion 24 ₄ is positioned at the top dead center position, and from this state, the idle gear 55 is slid to the solid line position in FIG. 4 to engage with the balancer drive gear 51, and then the idle shaft 11 is inserted into the support hole 25a. Lock.

By the above procedure, the rear balancer gear 60 can be assembled so that the rear balancer gear 60 has a predetermined phase with respect to the phase of the crankshaft 3.

The front balancer Bf is assembled by assembling the front balancer shaft 9 and the front balancer weight 67 in the lower casing 5 and temporarily fixing the front balancer gear 71 so as to have a predetermined phase, and the crankshaft 3 in a predetermined manner. The lower casing 5 is attached to the upper casing 4 temporarily fixed so as to be in phase.
Should be combined. The front balancer Bf can be easily assembled because the front balancer Bf is arranged at a position shallow from the opening of the lower casing 5.

The back balancer adjustment of the rear balancer Br is performed by the rear balancer shaft 10 including an eccentric shaft.
And the rotational position of the idle shaft 11 is adjusted. As shown in FIG. 8A, with respect to the axis P of both ends of the rear balancer shaft 10 supported by the third journal support portion 25 ₃ and the fourth journal support portion 25 ₄ of the casing raised portion 41, The axis P'of the eccentric portion 10b that supports the needle bearing 56 and the second needle bearing 57 is eccentric by the distance β, and the third journal portion 25 ₃ and the fourth journal portion 25 ₃ of the upper casing 4 are also eccentric.
Idle shaft 11 supported by journal part 25 ₄
The axis Q 'of the eccentric portion 11b supporting the idle gear 55 is eccentric by the distance γ with respect to the axis Q at both ends.
When the axis O of the crankshaft 3 is set, the angle θ formed between the line segment QO and the line segment QP is set to approximately 90 °.

First, as shown in FIG. 8 (A), the eccentric portion 10b (hatched portion) of the rear balancer shaft 10 is eccentrically attached to the arrow a substantially parallel to the direction of the line segment QP, and temporarily fixed, In addition, the eccentric portion 11b (hatched portion) of the idle shaft 11 is eccentrically provided in the arrow b direction substantially parallel to the direction of the line segment OQ and temporarily fixed. At this time, the rear balancer gear 6
0 is in a loose state with the idle gear 55,
The meshing between the idle gear 55 and the balancer driving gear 51 is also loose.

In this state, when the idle shaft 11 is rotated and fixed in the direction c in FIG. 8A by a predetermined angle (for example, about 120 °), the eccentric portion 1 of the idle shaft 11 is fixed.
The axis Q ′ of 1b moves in the direction of arrow e in FIG. 8B so as to approach the crankshaft 3, and the backlash between the balancer drive gear 51 and the idle gear 55 is adjusted to an appropriate size. At this time, the distance between the idle gear 55 and the rear balancer gear 60 slightly decreases, but the meshing between the idle gear 55 and the rear balancer gear 60 is maintained in a loose state, so that the idle gear 55 moves in the direction of the arrow e. Can be smoothly moved.

As described above, the balancer drive gear 51
When the backlash between the idle gear 55 and the idle gear 55 is adjusted, the rear balancer shaft 10 is fixed by rotating the rear balancer shaft 10 in the direction of arrow d in FIG. 8A by a predetermined angle (for example, about 90 °). This allows the rear balancer gear 60 to move to the position shown in FIG.
(B), the rear balancer gear 60 is moved.
The backlash between the gear and idle gear 55 is adjusted to an appropriate size. At this time, since the distance between the idle gear 55 and the rear balancer gear 60 has been slightly reduced in the previous process, the amount of movement of the rear balancer gear 60 in the direction of arrow f can be reduced accordingly. This rear balancer gear 60
Of course, the backlash between the already adjusted balancer drive gear 51 and idle gear 55 is not affected by the movement in the direction of arrow f.

The backlash of the front balancer Bf can be easily adjusted only by rotating the front balancer shaft 9 having the eccentric portion 9b. That is, the third journal portion 26 ₃ and the two ends of the axis of the fourth front balancer shaft 9 supported by the journal portion 26 ₄ of the lower casing 5, the axis of the eccentric portion 9b for supporting the front balancer gear 71 is predetermined When the front balancer shaft 9 is rotated, the front balancer gear 71 approaches and separates from the balancer driving gear 51 of the crankshaft 3 to adjust the backlash.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

For example, although the present invention is applied to the rear balancer Br in the embodiment, it may be applied to the front balancer Bf.

[0051]

As described above, according to the invention described in claim 1, when the idle shaft is rotated in the second step to adjust the distance between the idle gear and the balancer drive gear to the optimum backlash distance. Since the distance between the idle gear and the balancer gear is set to a distance larger than the optimum backlash distance in advance, the backlash adjustment by rotating the balancer shaft is performed while avoiding the interference between the idle gear and the balancer gear. It can be done easily. When the balancer shaft is rotated in the third step to adjust the distance between the idle gear and the balancer gear to the optimum backlash distance, the balancer shaft is shortened to some extent in the second step because the distance between the idle gear and the balancer gear is reduced. The backlash between the idle gear and the balancer drive gear, which has already been adjusted, does not change.

According to the invention described in claim 2,
Since a groove is formed at one end of the balancer shaft and the idle shaft extending from the casing to the outside, it is possible to easily backlash from the outside even while the engine is running by simply engaging the tool with the groove and rotating it. Adjustments can be made.

[Brief description of drawings]

FIG. 1 is an overall side view of an engine mounted on a motorcycle.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

5 is a view in the direction of arrow 5 in FIG.

6 is a sectional view taken along line 6-6 of FIG.

7 is an enlarged view of a main part of FIG.

FIG. 8 is an explanatory diagram of the operation

[Explanation of symbols]

3 Crankshaft 10 Rear Balancer Shaft (Balancer Shaft) 10a Groove 10b Eccentric Part 11 Idle Shaft 11a Groove 11b Eccentric Part 51 Balancer Drive Gear 55 Idle Gear 58 Rear Balancer Weight (Balancer Weight) 60 Balancer Gear

Claims (2)

[Claims] 1. A balancer drive gear (51) provided on a crankshaft (3) is meshed with an idle gear (55) rotatably supported by an eccentric part (11b) of an idle shaft (11), and the idle Gear (5
5) to the eccentric part (10) of the balancer shaft (10).
Balancer weight (58) rotatably supported on b)
The balancer gear (60) provided on the crankshaft (3) and the idle shaft (1).
A balancer device for an engine in which a line segment connecting (1) and a line segment connecting an idle shaft (11) and a balancer shaft (10) intersect at a substantially right angle, the idle shaft (11) and the balancer shaft (1
By rotating 0), the distance between the idle gear (55) and the balancer drive gear (51) is set larger than the optimal backlash distance, and the distance between the idle gear (55) and the balancer gear (60) is set. By reducing the distance between the idle gear (55) and the balancer gear (60) by rotating the idle shaft (11) and the first step of setting the optimal backlash distance larger, the idle gear (55) and the balancer By adjusting the distance between the drive gears (51) to the optimum backlash distance and rotating the balancer shaft (10),
A third step of adjusting the distance between the idle gear (55) and the balancer gear (60) to an optimum backlash distance,
A method for adjusting backlash in a balancer device for an engine, comprising: 2. A balancer shaft (10) and an idle shaft (1) extending from the casing (4) to the outside.
The engine (1) according to claim 1, characterized in that grooves (10a, 11a) with which a tool for rotating the balancer shaft (10) and the idle shaft (11) are engaged are formed at one end of (1). Backlash adjustment method for balancer device.