Chain guide structure for chain drive type transmission mechanism

Patent metadata

Field	Value
Publication number	US-9469375-B2
Application number	US-201514640748-A
Country	US
Kind code	B2
Filing date	Mar 6, 2015
Priority date	Mar 11, 2014
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A chain guide structure for a chain drive type transmission mechanism which ensures that even when a solid matter, such as a small stone, gets nipped and a strong impact is exerted on a chain guide, the chain guide deforms so as to absorb the impact and permit the small stone or the like to be swiftly eliminated. The chain guide fastened to the engine case is provided so as to cover a drive chain wound around a drive sprocket, at a part of the periphery of the drive sprocket and in an arcuate form. The chain guide is formed with a brittle portion lower in strength than other portions thereof. The brittle portion is located above and in the vicinity of a front end portion at which the chain guide is situated closest to the drive chain. Thus, an engine case can be protected from damage.

First claim

What is claimed is:

1. A chain guide structure for a chain drive transmission mechanism comprising:
a drive chain for transmitting motive power, the drive chain being looped around and between a drive sprocket and a driven sprocket, the drive sprocket being fitted to an output shaft protruding outside from an engine case of an internal combustion engine mounted on a vehicle, the driven sprocket being provided on a side of a rear wheel;
a chain guide fastened to the engine case is provided for covering the drive chain wound around the drive sprocket, at a part of a periphery of the drive sprocket and in an arcuate form; and
said chain guide being formed with a brittle portion lower in strength than other portions thereof, the brittle portion being located in an upper vicinity of a front end portion at which the chain guide is situated closest to the drive chain.

2. The chain guide structure for a chain drive transmission mechanism according to claim 1 , wherein a guide surface, facing the drive chain, of the chain guide is disposed so that a spacing between the guide surface and the drive chain gradually increases along an obliquely upward direction from the front end portion at which the spacing is the smallest.

3. The chain guide structure for a chain drive transmission mechanism according to claim 1 , wherein the brittle portion of the chain guide is formed by thinning.

4. The chain guide structure for a chain drive transmission mechanism according to claim 2 , wherein the brittle portion of the chain guide is formed by thinning.

5. The chain guide structure for a chain drive transmission mechanism according to claim 1 , wherein a fastening portion, fastened to the engine case, of the chain guide is provided in a position which is not in a direction from a center of rotation of the drive sprocket toward the brittle portion.

6. The chain guide structure for a chain drive transmission mechanism according to claim 2 , wherein a fastening portion, fastened to the engine case, of the chain guide is provided in a position which is not in a direction from a center of rotation of the drive sprocket toward the brittle portion.

7. The chain guide structure for a chain drive transmission mechanism according to claim 3 , wherein a fastening portion, fastened to the engine case, of the chain guide is provided in a position which is not in a direction from a center of rotation of the drive sprocket toward the brittle portion.

8. The chain guide structure for a chain drive transmission mechanism according to claim 5 , wherein the chain guide is fastened at its fastening portion to a fastening boss portion which is formed to project from the engine case and to be brittle.

9. The chain guide structure for a chain drive transmission mechanism according to claim 1 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

10. The chain guide structure for a chain drive transmission mechanism according to claim 2 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

11. The chain guide structure for a chain drive transmission mechanism according to claim 3 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

12. The chain guide structure for a chain drive transmission mechanism according to claim 5 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

13. The chain guide structure for a chain drive transmission mechanism according to claim 7 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

14. A chain guide structure for a chain drive transmission mechanism comprising:
a drive chain for transmitting motive power, the drive chain being looped around and between a drive sprocket and a driven sprocket;
a chain guide for covering the drive chain wound around the drive sprocket, at a part of a periphery of the drive sprocket and in an arcuate form; and
said chain guide being formed with a brittle portion lower in strength than other portions thereof, the brittle portion being located in an upper vicinity of a front end portion at which the chain guide is situated closest to the drive chain.

15. The chain guide structure for a chain drive transmission mechanism according to claim 14 , wherein a guide surface, facing the drive chain, of the chain guide is disposed so that a spacing between the guide surface and the drive chain gradually increases along an obliquely upward direction from the front end portion at which the spacing is the smallest.

16. The chain guide structure for a chain drive transmission mechanism according to claim 14 , wherein the brittle portion of the chain guide is formed by thinning.

17. The chain guide structure for a chain drive transmission mechanism according to claim 14 , wherein a fastening portion, fastened to the engine case, of the chain guide is provided in a position which is not in a direction from a center of rotation of the drive sprocket toward the brittle portion.

18. The chain guide structure for a chain drive transmission mechanism according to claim 16 , wherein a fastening portion, fastened to an engine case, of the chain guide is provided in a position which is not in a direction from a center of rotation of the drive sprocket toward the brittle portion.

19. The chain guide structure for a chain drive transmission mechanism according to claim 17 , wherein the chain guide is fastened at its fastening portion to a fastening boss portion which is formed to project from the engine case and to be brittle.

20. The chain guide structure for a chain drive transmission mechanism according to claim 14 ,
wherein the guide surface of the chain guide is configured so that:
the front end portion thereof situated closest to the drive chain is a lower end portion thereof; and
a portion thereof in a vicinity of a position where the drive chain starts being wound around the drive sprocket is a rear end portion thereof.

Assignees

• Honda Motor Co Ltd

Inventors

• Nakano Kenichi

Classifications

• B62K11/04

  characterised by the engine being between front and rear wheels · CPC title

• B62M2009/007

  Guides to prevent chain from slipping off the sprocket · CPC title

• B62M9/06 Primary

  using a single chain, belt, or the like · CPC title

• B62M7/02

  with engine between front and rear wheels · CPC title

• F16H7/18 Primary

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