Patent ID: 12234403

DETAILED DESCRIPTION

FIG.1shows the relative change of the volume δV in % of an expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature T in ° C.

The expanding wax examined forFIG.1was produced by mixing the commercially available waxes RubiTherm RT35, Mahle-Beer, and Paramelt Dilavest 0-30 at equal proportions and contains the alkanes listed in the following Table 1. The substance amount proportions were determined by gas chromatography.

TABLE 1Percentage ofChainMeltingthe substanceNamelengthtemperature/° C.amount/%n-dodecane12−100.0n-tridecane13−50.1n-tetradecane1469.5n-pentadecane1596.2n-hexadecane16183.9n-heptadecane17216.5n-octadecane182815.8n-nonadecane19329.1n-eicosane203710.4n-heneicosane214011.2n-docosane22449.1n-tricosane23486.1n-tetracosane24504.4n-pentacosane25543.1n-hexacosane26561.8n-heptacosane27590.8n-octacosane28610.3n-nonacosane29640.3n-triacontane30650.0Total98.5

For measuring the temperature dependency of the volume of the expanding wax, an initial volume of 3198.4 mm 3 of the expanding wax was filled into a cylindrical measuring cartridge (6 mm inner diameter, 114 mm inner length) using a cylindrical plunger (3.98 mm diameter, 12.4 mm 2 cross-sectional area) at an initial temperature of −10° C.

The measuring cartridge was subjected to a temperature ramp in a temperature control oven. At each examined temperature, the path the plunger had been driven out of the cartridge as compared to the initial temperature by the expansion of the expanding wax against a counterforce of 3 N was detected using a displacement detector after a waiting time of about min.

The relative change of the volume of the expanding wax was calculated as the product of the detected path and the cross-sectional area of the plunger divided by the initial volume.FIG.1shows the values obtained in this way for the rise in temperature (circles) and the reduction of the temperature (squares) of the expanding wax.

The essential components (percentage of the substance amount >5%) of the expanding wax examined forFIG.1have melting temperatures within the range of 6° C. to 48° C. (Table 1). Consequently, the expanding wax comprises at least one solid and at least one liquid phase in an entire operating temperature range of about 10° C. to about 50° C.

As can be seen inFIG.1, this results in an approximately linear relative increase in volume with a rising temperature in the operating temperature range. A linear regression (dotted line) of the measuring data in this range shows a correlation coefficient of R2=0.96.

Altogether, a relative increase in volume of 15% is reached over the examined temperature range of −10° C. to +60° C. which is sufficient to compensate the temperature dependency of the gas pressure spring. With a relative increase in volume of about 15%, it is possible to realise a compensation stroke which is sufficient to fully compensate or even overcompensate the temperature dependency of the gas spring at suitable translation ratios in the construction.

An overcompensation offers the possibility of working quite flexibly and of appropriately adjusting precisely the desired expansion for each gas pressure spring type by admixing corresponding oils exhibiting a lower increase in volume.

FIG.2shows the relative change of the volume δV in % of another expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature T in ° C.

The expanding wax examined forFIG.2was produced by mixing three commercially available waxes from the company Orbesen having melting ranges of 6° C. to 12° C., of 15° C. to and of 56° C. to 62° C. at equal proportions and contains the primary alcohols listed in the following Table 2. The substance amount proportions were determined by gas chromatography.

TABLE 2Percentage ofChainMeltingthe substanceNamelengthtemperature/° C.amount/%n-octanol8−160.0n-decanol10743.8n-dodecanol12240.0n-tetradecanol143824.0n-hexadecanol164931.4n-octadecanol18590.0Total99.3

The relative change of the volume of the expanding wax was determined as described in connection withFIG.1. In contrast toFIG.1, an initial temperature of −20° C. was selected.

The essential components (percentage of the substance amount >5%) of the expanding wax examined forFIG.1have melting temperatures within the range of 7° C. to 59° C. (Table 2). Consequently, the expanding wax exhibits at least one solid and at least one liquid phase in an entire operating temperature range of about 10° C. to about 50° C.

As can be seen inFIG.2, this results in an approximately linear relative increase in volume with rising temperatures in the operating temperature range. A linear regression (dotted line) of the measuring data in this range shows a correlation coefficient of R2=0.98.

Altogether, a relative increase in volume of 12% is reached over the examined temperature range of −20° C. to +75° C. which is sufficient to compensate or even overcompensate the temperature dependency of the gas pressure spring.

Although the invention has been illustrated and described in greater detail with reference to the exemplary embodiments, the invention is not limited to the examples disclosed, and further variations can be inferred by a person skilled in the art, without departing from the scope of protection of the invention.

For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.