JPS6141463Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a tensioner mechanism that applies a constant tension to an endless conveying body in a winding transmission mechanism in which an endless conveying body such as a chain is suspended between at least two shafts.

Conventionally, in this type of tensioner mechanism, the mechanism for energizing the slipper is disposed outside the endless feeding body, so it has been difficult to make the entire tensioner device compact.

The present invention relates to an improvement of a tensioner mechanism for an endless feeding body that overcomes these difficulties, and its purpose is to provide a compact tensioner mechanism that can prevent lateral vibration of the endless feeding body.

An embodiment shown in FIGS. 1 to 3 will be described below.

The illustrated embodiment is applied to an overhead valve type valve mechanism in a motorcycle engine, and includes:
Reference numeral 1 denotes a drive sprocket that is integrally fitted to the crankshaft of the engine, and a pair of cam sprockets 2 are rotatable along the same plane as the drive sprocket 1 about an axis parallel to the crankshaft. , 3 are pivoted.

A chain 4, which is a type of endless conveyor, is spanned between the drive sprocket 1 and the cam sprockets 2 and 3, and when the drive sprocket 1 is rotated counterclockwise, the cam sprocket 2 is connected to the drive sprocket 1 through the chain 4. , 3 are rotated in the same direction at a constant rotational speed ratio.

Further, inside the chain 4 between the drive sprocket 1 and the cam sprocket 3, a tension slipper 7 swings toward and away from the chain 4 through a pin 6 adjacent to the drive sprocket 1. It is pivotally supported on the engine crankcase 5.

Furthermore, in a space surrounded by the chain 4, a tensioner 9 is fixed to the crankcase 5 by bolts 8, pointing from the drive sprocket 1 to the cam sprocket 2.

The tensioner 9 includes a tensioner cylinder 10, a piston (not shown) slidably fitted into the cylinder 10, and a piston rod 11 integrally provided with the piston.
It consists of a bracket 12 fixed to the tip of the piston rod 11, and a compression coil spring 13 which is loosely fitted into the piston rod 11 and interposed between the tensioner cylinder 10 and the bracket 12. Spring 1
The piston rod 11 is always urged to protrude outward by the spring force of 3, and the piston rod 11 is damped by the viscous frictional force of the oil in the cylinder 10 against the piston. There is.

Further, pins 14 and 1 are provided on both sides of the tension slipper 7 near the tip and on both sides of the bracket 12.
5 and a pair of tension plates 16
Both ends are pivotally connected.

Furthermore, a wear-resistant material 17 consisting of a rubber surface lined with Teflon or the like is bonded together by baking or the like over the entire inner surface of the tension slipper 7 (including the inner surfaces on both sides of the base of the slipper 7). A wear-resistant material 18 similar to the wear-resistant material 17 described above is also bonded to the inner surface of the tension plate 16 adjacent to the slipper 7 by baking or the like.

Note that 19 is a sleeve that is in contact with the outer inner surface of the base of the tension slipper 7 and is fitted onto the pin 6;
20 and 21 are chain guides that guide the chain 4.

Since the embodiment shown in FIGS. 1 to 3 is constructed as described above, the pin 15 of the tensioner 9 is urged toward the cam sprocket 2 by the spring force of the compression coil spring 13 of the tensioner 9. , this force is the tension plate 16
The tension is transmitted to the tension slipper 7 through the chain 4, and the tension slipper 7 is swung inward from the outer surface of the chain 4 around the pin 6.
As a result, the chain 4 can be kept under tension, and the rotational torque of the crankshaft is reliably transmitted to a cam (not shown) via the drive sprocket, the chain 4, and the cam sprockets 2, 3.

In addition, the reaction force from the chain 4 is supported by the compression coil spring 13 from the slipper 7 via the pin 14, tension plate 16, pin 15, and bracket 12, and the fluctuation of the reaction force from the chain 4 is Since it is damped by the viscous frictional force of the oil in the cylinder 10, when a substantially uniform tension force is applied to the chain 4, vibrations in a direction perpendicular to the longitudinal direction of the chain 4 are suppressed.

Furthermore, since the tensioner 9 is arranged in a closed space surrounded by the chain 4, the tensioner 9 is not located outside the chain 4, and the tensioner mechanism can be made compact.

Furthermore, wear-resistant materials 17 are bonded to the inner surfaces of both sides of the base of the slipper 7, and the above-mentioned wear-resistant materials 18 are bonded to the inner surfaces of both tension plates 16, so that the lateral vibration of the chain 4 is reduced. Prevented.

In the embodiment shown in FIGS. 1 to 3, the tensioner cylinder 10 is rigidly fixed to the crankcase 5 with two bolts 8, but the base of the tensioner cylinder 10 is fixed with one bolt 8. It may be pivotally mounted so that it can swing freely, and such an embodiment can also provide the same effects as the embodiments shown in FIGS. 1 to 3.

Further, in the embodiment described above, the endless feeding body was the chain 4, but it may also be a belt or the like.

In this case, one of the members that abuts from the outside of the endless transport body is pivotally supported inside the transport body, and the tensioner is connected to the inside of the transport body through a pair of connecting members that are rotatable to the other of the contact members. Therefore, the slack of the conveying body is removed by the tensioner via the abutting member and the connecting member, and vibration of the conveying body is prevented.

Further, in the present invention, since the tensioner is disposed inside the endless feeding body, the endless feeding body tensioner mechanism can be downsized. Further, in the present invention, the conveying body is pressed inward from the outside and straddles both sides of the conveying body in the width direction, and swings around an axis parallel to the axis of the wheel in the vicinity of the drive wheel inside the conveying body. One end of the abutment member is freely pivoted, and the longitudinal center portion of the abutment member is gently curved toward the center portion of the endless transport body.
Even if the tension acting on the endless feeding body changes, the endless feeding body does not deform as much as shown in the left, and as a result, the elongation of the feeding body is sufficiently absorbed by the abutting member, and the feeding body deforms. A stable side shape can be maintained, no excessive force is applied to the conveying body, the conveying body is less likely to be damaged, and its durability is improved.

Furthermore, in the present invention, the pair of connecting members that connect the abutment member and the movable part of the tensioner are disposed to sandwich both sides of the conveying body, so that the tension acting on the endless conveying body changes and Even if the abutting member swings, the endless feeding body does not come off from the corresponding abutting member, and the endless feeding body maintains a stable state of wrapping around the driving vehicle body and driven wheels without swinging significantly in the width direction. can do.

[Brief explanation of the drawing]

FIG. 1 is a side view illustrating an embodiment of the endless conveyor tensioner mechanism according to the present invention, and FIGS.
The figures are cross-sectional views taken along lines - and - in Fig. 1, and Fig. 4 is a side view of main parts of another embodiment. 1... Drive sprocket, 2, 3... Cam sprocket, 4... Chain, 5... Crank case, 6... Pin, 7... Tension slipper, 8... Bolt, 9... Tensioner, 10 …
... Tensioner cylinder, 11 ... Piston rod, 12 ... Bracket, 13 ... Compression coil spring, 14, 15 ... Pin, 16 ... Tension plate, 17, 18 ... Wear-resistant material, 19 ...
...Sleeve, 20, 21...Chain guide.

Claims (1)

[Scope of Claim for Utility Model Registration] An endless conveying body wrapped around a drive wheel and a double-acting wheel, and an endless conveying body that presses inward from the outside of the conveying body and straddles from both sides of the conveying body in the width direction and inside the conveying body. a contact member, one end of which is swingably supported near the drive wheel of the wheel about an axis parallel to the axis of the wheel, and the other end of the contact member sandwiching both sides of the transport body. a pair of connecting members, one end of which is pivotally connected;
a tensioner disposed inside the feeding body so as to be oriented diagonally with respect to the longitudinal direction of the abutting member, and a central portion in the longitudinal direction of the abutting member is gradually moved toward a central portion of the endless feeding body; curved into
An endless conveyor tensioner mechanism, wherein the other end of the connecting member is pivotally connected to a movable part of the tensioner. 2. The endless feeding body tensioner mechanism according to claim 1, wherein a wear-resistant material that slides into contact with the feeding body is fixed to a side surface of each feeding body of the pair of connecting members.