JPH0364354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for adjusting the tension of a chain in, for example, a chain-driven motorcycle.

This type of device generally had a structure in which the axle of the drive wheel was moved back and forth within a long hole in the rear hawk by operating a chain puller, but this device had a long hole in the rear hawk. This not only reduced the rigidity of the rear hawk, but also required the axle to be firmly tightened in the axial direction once the tension was adjusted.

As a countermeasure for this, a circular through hole was recently provided in the rear fork, and an adjustment piece was rotatably fitted into this hole, and the axle was inserted and held at an eccentric position of the adjustment piece, so that the adjustment piece could be inserted into the hole. A device has been developed in which the axle can be moved back and forth by rotating it.

However, with this structure, since the axle rotates together with the adjustment piece, the center of the axle moves not only in the front-rear direction but also in the vertical direction. Therefore, the center of the axle moves up and down each time the chain tension is adjusted. However, as a result, the center of gravity of the vehicle as a whole moved up and down, causing a problem in which the handling performance changed.

The present invention has been made based on the above circumstances, and its purpose is to reduce the reduction in the rigidity of the rear hawk, and to
To provide a chain or belt tensioning device for a vehicle that can maintain a constant vehicle height without vertically changing the axle center.

That is, in the present invention, a substantially cylindrical first piece member is rotatably fitted into a circular through hole formed in the rear arm, a circular through hole is also provided at an eccentric position of this first piece member, and this through hole is provided at an eccentric position of the first piece member. A substantially cylindrical second piece member is rotatably fitted into the hole, and an axle is inserted through the eccentric position of the second piece member, so that the axle is moved in the vertical direction as the second piece member rotates. The above objective is achieved by absorbing the amount of movement by the rotation of the first bridge member.

An embodiment of the present invention will be described below based on drawings in which the present invention is applied to a motorcycle.

In the figure, reference numeral 1 denotes a frame, which mainly includes a main pipe 2, a pair of left and right down tubes 3, 3, seat pillar tubes 4, 4, back stays 5, 5, and the like. An engine 6 is mounted in a space surrounded by the main pipe 2, down tubes 3, 3, and seat biller tubes 4, 4 of the frame 1. A transmission case 8 is integrally connected to the rear of the crankcase 7 of the engine 6, and on one side of the transmission case 8 is a drive sprocket 9 that outputs the power of the engine 6.
is provided. Seat pillar tube 4,4
Brackets 10, 10 (only one is shown) are welded to the front surface of the lower end of the rear arm 12, and the front end of the rear arm 12 is swingably supported between these brackets 10, 10 via a pivot shaft 11. There is.
The rear arm 12 is made of, for example, an aluminum alloy and has a pair of left and right rear arm structures 13 each having a rectangular cross section.
a, 13b, these rear arm structures 13
The front ends of a and 13b are connected to each other by a cross member 14. A link mechanism 17 that combines an L-shaped link 15 and a rod 16 is provided between the upper surface of the cross member 14 and the backstays 5, 5, and one link mechanism 17 is provided between the link mechanism 17 and the main pipe 2. A shock absorber 18 is installed. Therefore, the rear arm 12 is suspended from the vehicle body by one shock absorber 18 via the link mechanism 17.

The rear ends of the rear arm structures 13a, 13b are open, and arm ends 19, 20 made of aluminum alloy are fitted into these openings and fixed by welding or the like. These arm ends 19, 20
have a wall thickness equal to or greater than the cross-sectional shape of the rear arm structures 13a, 13b, and these arm ends 19,
20 has circular through holes 21, 21 facing each other, and one end is connected to the arm end 1.
9, 20 is open at the rear surface, and the other end is through hole 21,
Slots 22, 22 opening into 21 are formed. In addition, a plurality of alignment marks 23 are carved at equal intervals on the outer surfaces of the arm ends 19 and 20 at the periphery of the opening of the upper half of the through hole 21. And these arm ends 19, 20
In between, there are chain pullers 24, 24 according to the present invention.
An axle 25 is supported via. The axle 25 is hollow and rotatably supports a hub 28 of a rear wheel 27 as a driving wheel via bearings 26, and a driven sprocket 29 is attached to one side of the hub 28 with bolts 30. It is tightened by a brake drum 31 and is integrally provided with a brake drum 31 on the other side. The opening of the brake drum 31 is closed by a brake shoe plate 32 rotatably provided on the axle 25, and brake shoes 33, 33 are attached to the brake shoe plate 32. A rim 35 is connected to the outside of the hub 28 via a large number of wire spokes 34, and a tire 36 is fitted into the rim 35. A chain 37 is wound endlessly between the driving sprocket 9 on the engine 6 side and the driven sprocket 29 on the rear wheel 27 side, so that the engine power is transmitted through the chain 37 to the rear wheel 27. transmitted to.

Next, the structure of the chain pullers 24, 24 will be explained in detail with reference to FIG. 4, but since they have the same structure, one side will be explained as a representative. That is,
38 is a first piece member having a cylindrical outer shape;
It is fitted into the through hole 21 of the arm end 19 so as to be rotatable in the direction around the axis. A circular through hole 39 is provided at an eccentric position of the first piece member 38, and the center _O2 of this through hole 39 is eccentric with respect to the center _O1 of the through hole 21. The first bridge member 38 is provided with a slot 40 whose one end is open to the outer circumferential surface and whose other end is open to the circumferential surface of the through hole 39, so that the diameter can be reduced. Note that the first piece member 3
A pair of alignment marks 41, 41 are engraved on the outer peripheral surface of the hole 8, facing each other in the radial direction, and a plurality of alignment marks 4 are formed on the opening periphery of the through hole 39 over half the circumference.
2... are carved at equal intervals. Also,
Reference numerals 43 and 43 are recesses into which a holding tool is inserted when rotating the first piece member 38.

A cylindrical second piece member 44 is fitted into the through hole 39 of the first piece member 38 so as to be rotatable around the axis. A circular axle insertion hole 45 is provided at an eccentric position of the second bridge member 44.
The center O ₂ of this axle insertion hole 45 is eccentric with respect to the center O ₂ of the through hole 39 . and through hole 21
, the center O ₂ of the through hole ₃₉ and the center O ₃ of the axle insertion hole 45 are the straight line X connecting the pivot point of the rear arm 12 and the center O ₁ when the axle insertion hole 45 is moved forward the most _{1 − _ _ _ _ _ _ _ _}
The relationship between The second bridge member 44 has one end open to the outer peripheral surface and the other end to the axle insertion hole 4.
A slot 46 that opens on the circumferential surface of the piece 5 is provided, and is configured to be able to reduce its diameter similarly to the first piece member 38 described above. Note that reference numerals 53 and 53 are match marks engraved on the outer end surface of the second bridge member 44 so as to face each other in the radial direction. The axle 25 is fitted and supported within the axle insertion hole 45, and the center _O4 of the axle 25 coincides with the center _O3 of the axle insertion hole 45. Further, the inner end surface of the second bridge member 44 projects further inward than the inner surface of the arm end 19, that is, toward the hub 28 side. The end face of this protrusion 47 is connected to the axle 25.
The bearing 2 is inserted through the collars 48, 48 inserted into the
6... are pressed in the axial direction of the axle 25, and this pressing positions the axle 25 along the axial direction. Further, the two opposing parts of the outer circumferential surface of the protrusion 47 are finished flat, and a tool such as a spanner used when rotating the second piece member 44 is engaged with the flat parts 49, 49. be done. Further, a bolt 50 is inserted through the rear end of the arm end 19 in a direction perpendicular to the slot 22, and the chain puller 24 is fixed by tightening the insertion end of the bolt 50 with a nut 51.

Note that the openings at both ends of the axle 25 are provided with rubber caps 5.
2 and 52 in a watertight manner.

Next, the procedure for adjusting the tension of the chain 37 will be explained with reference to FIGS. 4 to 6. In this embodiment, a case will be described in which the axle 25 at the most advanced position is moved backward by a distance L from this position.

First, after loosening the nut 51 and releasing the tightening of the chain puller 24, the second piece member 44 is rotated by α° clockwise using a spanner or the like. Due to this rotation, the center O ₄ of the axle 25 similarly rotates clockwise by α'° about O ₂ and moves to the position O ₄ '. At this time, the center O ₄ of the axle 25 is a straight line X ₁ −X ₁
Since it will be positioned higher than the
The piece member 38 is rotated counterclockwise. That is, when the angle between the straight line X ₂ - X ₂ connecting the center O ₂ of the first bridge member 38 and the above-mentioned position O ₄ ′ and the straight line _{X 1} - The second piece member 4
4, the center O ₄ ' of the axle 25 is rotated by β degrees counterclockwise around O ₂ , and as shown in _FIG . _X1
Therefore _, the axle 25 moves backward on the straight line X ₁ −X _{1 from the position O 4 before} adjustment.
This means that you have moved to the O ₄ ″ position, and from O ₄
This means that the distance between the shafts between the drive sprocket 9 and the driven sprocket 29 has been adjusted by the distance L (mm) up to O ₄ ″.In addition, such adjustment work is performed by both the left and right chain pullers 24, It goes without saying that the left and right alignments are carried out in step 24, respectively, but the left and right alignment is done using the alignment marks 23..., 42... and alignment marks 41, 41 and 53, 53 as guides.Then, the left and right chain pullers 24, 24 are adjusted. When this is completed, tighten the nut 51. Then, while tightening the first piece member 38 that the through hole 21 includes, this first piece member 3
8 tightens the second piece member 44 on the inside, and this second piece member 44 sequentially tightens the axle 25. As a result, the axle 25 and chain puller 24, 24
are positioned and held at arm ends 19 and 20.

Also, the center of the through hole 21 for the axle 25 located at the forefront
If you want to move further backwards beyond O ₁ ,
Follow the steps below. That is, as shown in FIG. 7, only the first piece member 38 is rotated 180° clockwise while the second piece member 44 remains in its original position.
When rotated, from O ₁ from the center as described above.
Since the distance l ₁ to O ₂ is equal to the distance l ₂ from the center O ₂ to O ₃ , the center O ₄ of the axle 25 is located on the center O ₁ of the through hole 21 . After that, if you perform the same adjustment operation as described above, the center of the axle 25 will be
O ₄ can be moved to position O ₄ on the straight line X ₁ −X ₁ .

Furthermore, in order to position the axle 25 at the forefront position to the rearmost position, as shown in FIG. , the center O ₄ can be moved to the position O ₄ ′′′′ on the straight line X ₁ −X ₁ .

However, the chain puller 2 with such a configuration
According to No. 4, 24, the through hole 21 is formed in a circular shape,
Since the inside of this through hole 21 is filled with the first piece member 38 and the second piece member 44 and tightened with the bolt 50, a space (hole) is formed in the arm ends 19, 20 for adjusting the position of the axle 25. is gone,
Arm ends 19 and 20 become rigid bodies, and
No reduction in cross-sectional area occurs. Therefore, the rigidity of the rear arm 12 is increased, and the occurrence of cracks and the like in the arm ends 19 and 20 can be prevented.

Moreover, the movement of the axle 25 in the vertical direction due to the rotation of the second bridge member 44 is absorbed by the rotation of the first bridge member 38 in the opposite direction. It can be moved back and forth on the straight line _X1 - _X1 connecting the center _O1 of the through hole 21. Therefore, even if the tension of the chain 37 is adjusted, the vehicle height can be kept constant.

Further, in this embodiment, the inner end surface of the second piece member 44 is made to protrude toward the hub 28 side, and the protruding portions 47, 47
are brought into contact with the bearings 25 through the collars 48, 48, so the protrusions 47, 47 function as spacers and position the axle 25 in the axial direction. Therefore, tightening the nut 51 also positions the axle 25 in the axial direction, so there is no need to firmly tighten the axle 25 in the axial direction as in the past. Since there is no need to apply any tightening force to the joints between the arm ends 19, 20 and the rear arm structures 13a, 13b, this greatly contributes to the prevention of cracks.

In the above-described embodiment, a chain was used to transmit power from the engine, but a toothed belt may also be used, for example.

Furthermore, the vehicle according to the present invention is not limited to a motorcycle, but may be a tricycle having one steering wheel at the front of the vehicle body and two driving wheels at the rear of the vehicle body. Any vehicle that has an axle installed between the left and right rear fork will suffice.

In the present invention described in detail above, a substantially cylindrical first piece member is rotatably fitted into a circular through hole formed in a rear arm, and a substantially cylindrical second piece member is installed at an eccentric position of the first piece member. Since the member is rotatably fitted and the axle of the drive wheel is inserted and supported at the eccentric position of this second piece member, there is no space left in the rear arm for adjusting the axle position, increasing the rigidity of the rear arm. . Furthermore, the vertical movement of the axle due to the rotation of the second bridge member is absorbed by the rotational displacement of the first bridge member, so the position of the axle can be adjusted on the same straight line along the front-rear direction of the rear arm. can do.
Therefore, even if the tension of the chain or belt is adjusted, the vehicle height can be kept constant.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a side view, FIG. 2 is a sectional view, FIG. 3 is a sectional view taken along the line - in FIG. 2, and FIGS. 4 to 8 are explanations of operation. It is a diagram. 13a, 13b...Rear arm (rear arm structure), 21, 39...Through hole, 25...Axle, 27
...Rear wheel (drive wheel), 37...Chain, 38...
...first piece member, 44...second piece member.

Claims (1)

[Claims] 1. In a vehicle in which the axle of the drive wheel is supported between the left and right rear arms and the drive wheel is driven by a chain or belt, a circular through hole is provided in the rear arm, and a substantially cylindrical hole is provided in the through hole. The first piece member is rotatably fitted and provided,
A circular through hole is also provided at the eccentric position of this first piece member, and a substantially cylindrical second piece member is rotatably fitted into this through hole, and at the eccentric position of this second piece member, A chain or belt tensioning device for a vehicle, characterized in that the above axle is inserted and supported.