Firestone EMDG198 manual HOW to USE Static Data Chart, Airstroke Actuation, 752 180, 349

HOW TO USE

THE STATIC DATA CHART

We also refer to this chart as the load/deflection (L/D) curve for an air spring. The force [1] is given on the right hand axis vs. the air spring height [2] as shown along the bottom axis; thus, load vs. deflection. The internal volume [3] is also given along the left hand axis, again vs. height [2]. It is called static data because the air spring is in a static, or non-moving, constant pressure condi- tion. In almost all cases the static curves were run using a two ply bellows; however, where a four ply bellows is available, use the two ply chart for it also.

AIRSTROKE ACTUATION

The important considerations are minimum height [4] (3.0 inches) and maximum recom- mended height [5] (10.1 inches). Subtracting one from the other gives the stroke potential for this part (10.1 – 3.0 = 7.1 inches). As an actuator, the entire stroke may be used, or any potion thereof. Ignore recommended airmount design height [6] and the corresponding darkened line [7]. This height is important in using the air spring as an isolator (AIRMOUNT). It has nothing to do with the concern here of actuation. To determine the force at any given height, simply move up the height line to where it intersects any of the static pressure curves. Then move to the right and read from the force scale [1].

EXAMPLE: At 80 psig, what is the force using a #22 from 4.0 to 9.0 inches, or 9.0 – 4.0 = 5.0 inch stroke? See [8] for force at 4.0 inches (7,180 #) and [9] for force at 9.0 inches (4,670 #). This example illustrates the primary difference between Firestone Airstrokes and conventional air cylinders. Air cylinders have a constant area for the pressure to work against, or constant effective area. the effective area and force of an air spring changes as the height changes.(There is one exception: notice the plateau section of reversible sleeve 1T type curves.)

[6]

Recommended

				Airmount		Static Data
			Design Height		1227
				9.5 Inches
11	Do	not use Airstroke in					11
	shaded area without
	consulting Firestone				120

	10										10
		[13]		[7]
100	9							100			9
				Volume
x
				100 Psig
IN.	8										8
				[12]
CU	752	[10]							[8]		7,180
	7							80
BUMPER)											7
	6										6
								60
VOLUME (WITHOUT	5			[9]							5	FORCE LBS x 1000
			[15]								4,670
											4,280
	4		[14]						[11]		4
	349							40
	3										3
	2							20 Psig			2
[3]												[1]
	1										1
	MAX. HT.		[5]						[16]	MIN. HT. [4]
	12	11	10	9	8	7	6	5	4	3
			[2]	HEIGHT		IN.		Bumper Contact
									(4.2 IN.)

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