Case TR270, TR310, TV370 Track Loader Service Manual (Tier 4B)

Description

Table of Contents

1. Contents
2. Introduction
3. Engine
4. Front Axle System
5. Rear Axle System
6. Hydrostatic Drive
7. Brakes and Controls
8. Hydraulic Systems
9. Frames and Ballasting
10. Wheels
11. Cab Climate Control
12. Electrical System
13. Front Loader and Bucket
14. Platform, Cab, Bodywork and Decals
15. Specials Tool Index

Manual Extract: Chain drive – Measure

1. The individual joints in a roller chain articulate as they enter and leave the sprockets. This articulation results in wear on the pins and bushings. Material that is worn away from these surfaces will cause the chain to gradually elongate. Chains do not stretch. Material is worn from pin and bushing.
Critical dimensions of the chain are as follows: 1. 2X pitch
2. Wear plus 2X pitch
3. Elongation due to pin and bushing wear

Elongation is normal and may be minimized by proper lubrication and drive maintenance. The rate of wear is dependent upon: the relationship between the load and the amount of bearing area between pin and bushing, the material and surface condition of the bearing surfaces, the adequacy of lubrication, and the frequency and degree of articulation between pins and bushings.

The latter is determined by the quantity of sprockets in the drive, their speeds, the number of teeth and the length of the chain in pitches.
An accurate wear measurement (1) can be made by using the above illustration. Measure as closely as possible from the center of one pin to the center of another.

The more pitches (pins) contained within the measurement increase the accuracy. If the measured value exceeds the nominal by more than the allowable percentage the chain should be replaced. The maximum allowable wear elongation is approximately 3 % for most industrial applications, based upon sprocket design. The allowable chain wear in percent can be calculated using the relationship: 200/ (N), where (N) is the number of teeth in the large sprocket. This relationship is often useful since the normal maximum allowable chain wear elongation of 3 % is valid only up to 67 teeth in the large sprocket. In drives having fixed center distances, chains running in parallel or where smoother operation is required, wear should be limited to approximately 1.5 %.

For example, if 12 pitches (12 pins) of a #80 chain were measured and the result was 313.944 mm (12.360 in) or greater (using 3 % as the maximum allowable wear), the chain should be replaced. Anything less than 313.944 mm (12.360 in) would still be acceptable by most industrial standards

Identify the Tier Level of your Equipment (Read our Article on Tier Level )