Power unit having cam chain tensioner pivot mechanism

Patent metadata

Field	Value
Publication number	US-10006523-B2
Application number	US-201615271711-A
Country	US
Kind code	B2
Filing date	Sep 21, 2016
Priority date	Sep 25, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A compact power unit with a sufficient clearance between a stud bolt and a fixing shaft of a cam chain tensioner pivot mechanism for supporting a cam chain tensioner guide. The power unit including a crankshaft, a stud bolt configured to fix a crankcase and a cylinder body to each other, a cam chain, a cam chain tensioner mechanism including a cam chain tensioner guide, and a cam chain tensioner pivot mechanism including a pivot plate, a fixing shaft, and a swinging shaft, the fixing shaft and the swinging shaft are arranged so as to straddle the axis of the stud bolt as viewed in the axial direction of the crankshaft.

First claim

What is claimed is:

1. A power unit having a cam chain tensioner pivot mechanism, the power unit comprising:
a crankcase;
a cylinder body including a cylinder, said cylinder being operatively positioned within the crankcase;
a crankshaft rotatably supported by the crankcase;
a plurality of stud bolts configured to fix the crankcase and the cylinder body to each other;
a cam chain driving sprocket disposed at one end portion of the crankshaft;
a cam chain wound around the cam chain driving sprocket, the cam chain transmitting power to a valve gear;
a cam chain tensioner mechanism including a cam chain tensioner guide providing a tension to the cam chain; and
a cam chain tensioner pivot mechanism configured to swingably support the cam chain tensioner guide by a pivot plate fixed to the crankcase by a fixing shaft and a swinging shaft inserted through the cam chain tensioner guide;
wherein, as viewed in an axial direction of the crankshaft, the fixing shaft and the swinging shaft are arranged so as to straddle an axis of at least one stud bolt of the plurality of stud bolts.

2. The power unit having the cam chain tensioner pivot mechanism according to claim 1 , wherein:
the cam chain tensioner pivot mechanism is disposed nearer to the valve gear than the crankshaft in a direction of a cylinder axis of the cylinder;
the crankcase is provided with a rib extending from a side of the cylinder body; and
the rib has a boss portion to which the fixing shaft is fixed.

3. The power unit having the cam chain tensioner pivot mechanism according to claim 2 , wherein:
the crankcase supports a main shaft to which power from the crankshaft is transmitted;
a clutch mechanism configured to connect and disconnect the power from the crankshaft, said clutch mechanism being disposed at one end portion of the main shaft; and
the clutch mechanism and at least part of the cam chain tensioner pivot mechanism are arranged so as to overlap each other as viewed in the direction of the cylinder axis.

4. The power unit having the cam chain tensioner pivot mechanism according to claim 3 , wherein:
a primary drive gear for transmitting power from the crankshaft is disposed on one side of the crankshaft;
a primary driven gear meshing with the primary drive gear on an inside of the clutch mechanism is disposed on one side of the main shaft; and
the rib is disposed so as to overlap the primary driven gear as viewed in the direction of the cylinder axis.

5. The power unit having the cam chain tensioner pivot mechanism according to claim 4 , wherein the power unit is mounted in a vehicle, and the main shaft and the crankshaft are arranged side by side in a horizontal direction of the vehicle.

6. The power unit having the cam chain tensioner pivot mechanism according to claim 5 , wherein:
the cam chain tensioner mechanism includes a cam chain tensioner that presses the cam chain tensioner guide;
the cam chain tensioner is disposed nearer to the valve gear than the cam chain tensioner guide in the direction of the cylinder axis;
the cam chain tensioner mechanism includes a tensioner receiving member interposed between the cam chain tensioner and the cam chain tensioner guide, the tensioner receiving member pressing the cam chain tensioner guide by receiving a pressing force of the cam chain tensioner;
the tensioner receiving member is swingably supported on the power unit by a tensioner receiving member swinging shaft; and
the tensioner receiving member swinging shaft is disposed nearer to the valve gear than the cam chain tensioner guide in the direction of the cylinder axis.

7. A power unit having a cam chain tensioner pivot mechanism, comprising:
a crankcase;
a crankshaft rotatably supported within the crankcase;
a plurality of stud bolts for fixing the crankcase and a cylinder body to each other;
a cam chain driving sprocket disposed at one end portion of the crankshaft;
a valve gear;
a cam chain wound around the cam chain driving sprocket, the cam chain transmitting power to said valve gear;
a cam chain tensioner guide for providing a tension to the cam chain; and
a cam chain tensioner pivot mechanism for swingingly supporting the cam chain tensioner guide by a pivot plate fixed to the crankcase by a fixing shaft and a swinging shaft inserted through the cam chain tensioner guide;
wherein, as viewed in an axial direction of the crankshaft, the fixing shaft and the swinging shaft are arranged to straddle an axis of at least one stud bolt of the plurality of stud bolts.

8. The power unit having the cam chain tensioner pivot mechanism according to claim 7 , wherein:
the cam chain tensioner pivot mechanism is disposed nearer to the valve gear than the crankshaft in a direction of a cylinder axis of a cylinder positioned within the cylinder body;
the crankcase is provided with a rib extending from a side of the cylinder body; and
the rib has a boss portion to which the fixing shaft is fixed.

9. The power unit having the cam chain tensioner pivot mechanism according to claim 8 , wherein:
the crankcase supports a main shaft to which power from the crankshaft is transmitted;
a clutch mechanism operatively connects and disconnects power from the crankshaft, said clutch mechanism being disposed at one end portion of the main shaft; and
the clutch mechanism and at least part of the cam chain tensioner pivot mechanism are arranged so as to overlap each other as viewed in the direction of the cylinder axis.

10. The power unit having the cam chain tensioner pivot mechanism according to claim 9 , wherein:
a primary drive gear for transmitting power from the crankshaft is disposed on one side of the crankshaft;
a primary driven gear meshing with the primary drive gear on an inside of the clutch mechanism is disposed on one side of the main shaft; and
the rib is disposed so as to overlap the primary driven gear as viewed in the direction of the cylinder axis.

11. The power unit having the cam chain tensioner pivot mechanism according to claim 10 , wherein the power unit is mounted in a vehicle, and the main shaft and the crankshaft are arranged side by side in a horizontal direction of the vehicle.

12. The power unit having the cam chain tensioner pivot mechanism according to claim 11 , wherein:
the cam chain tensioner mechanism includes a cam chain tensioner for pressing the cam chain tensioner guide;
the cam chain tensioner is disposed nearer to the valve gear than the cam chain tensioner guide in the direction of the cylinder axis;
the cam chain tensioner mechanism includes a tensioner receiving member interposed between the cam chain tensioner and the cam chain tensioner guide, the tensioner receiving member pressing the cam chain tensioner guide by receiving a pressing force of the cam chain tensioner;
the tensioner receiving member is swingably supported on the power unit by a tensioner receiving member swinging shaft; and
the tensioner receiving member swinging shaft is disposed nearer to the valve gear than the cam chain tensioner guide in the direction of the cylinder axis.

13. A power unit having a cam chain tensioner pivot mechanism, comprising:
a crankcase with a cylinder body being operatively positioned relative to the crankcase;
a crankshaft rotatably supported by the crankcase;
a plurality of stud bolts configured to fix the crankcase and the cylinder body to each other;
a cam chain driving sprocket disposed at one end portion of the crankshaft;
a cam chain wound around the cam chain driving sprocket, the cam chain transmitting power to a valve gear;
a cam chain tensioner guide for providing a tension to the cam ch

Assignees

• Honda Motor Co Ltd

Inventors

• Inomoto Yutaka
• Kobayashi Koji
• Shigematsu Keita
• Shirasuna Takamori

Classifications

• F01L1/02

  Valve drive (transmitting-gear between valve drive and valve F01L1/12) · CPC title

• F16H7/18

  Means for guiding or supporting belts, ropes, or chains (construction of pulleys F16H55/36) · CPC title

• F01L1/022

  Chain drive · CPC title

• F16H2007/0893

  Circular path · CPC title

• F02B61/02 Primary

  for driving cycles · CPC title