GAS PRESSURE SPRING COMPRISING AN EXPANDING WAX, DRIVE SYSTEM COMPRISING THE GAS PRESSURE SPRING

Abstract

A gas pressure spring is provided including an expanding wax as a compensating medium for reducing a temperature dependency of a spring force of the gas pressure spring in an operating temperature range of the gas pressure spring spanning a minimum temperature of 40 C. to +10 C. up to a maximum temperature of +40 C. to +100 C. The expanding wax includes at least one liquid phase and at least one solid phase in the entire operating temperature range, the expanding wax comprising a number of primary alcohols. Also provided is a drive system for a flap including a gas pressure spring for supporting the flap, and an electromechanical drive for driving the flap.

Claims

1. A gas pressure spring comprising an expanding wax as a compensating medium for reducing a temperature dependency of a spring force of the gas pressure spring in an operating temperature range of the gas pressure spring spanning a minimum temperature of 40 C. to +10 C. up to a maximum temperature of +50 C. to +100 C. wherein a. the expanding wax comprises at least one liquid phase and at least one solid phase in the entire operating temperature range; wherein the expanding wax is composed of a number of alkanes and a number of primary alcohols having chain lengths which differ from each other, c. wherein the primary alcohols constitute a percentage of the substance amount of 10% to 30% of the expanding wax; and d. wherein the primary alcohols contained in the expanding wax i. comprise a number of primary alcohols having a lower melting temperature than all alkanes contained in the expanding wax, and/or ii. comprise a number of primary alcohols having a higher melting temperature than all alkanes contained in the expanding wax.

2. The gas pressure spring according to claim 1, wherein the minimum temperature is 30 C. to 0 C. or 20 C. to 10 C.

3. The gas pressure spring according to claim 1, wherein the maximum temperature is +50 C. to +80 C.

4. The gas pressure spring according to one of claim 1, wherein the expanding wax comprises a plurality of alkanes having chain lengths which differ from each other.

5. The gas pressure spring according claim 1, wherein the alkanes have a minimum chain length within the range of 5 to 20, and a maximum chain length within the range of 20 to 35.

6. (canceled)

7. The gas pressure spring according to wherein the primary alcohols constitute a percentage of the substance amount of 10% to 25% of the expanding wax.

8. The gas pressure spring according to claim 1, wherein the expanding wax comprises a plurality of primary alcohols having chain lengths which differ from each other.

9. The gas pressure spring according to claim 1, wherein the primary alcohols have a minimum chain length within the range of 3 to 15 and a maximum chain length within the range of 10 to 25.

10. (canceled)

11. (canceled)

12. A drive system for a flap comprising: a. a gas pressure spring according to one of the claims 1 to 8 for supporting the flap; and b. an electromechanical drive, for driving the flap.

Description

BRIEF DESCRIPTION

[0050] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0051] FIG. 1 shows the relative change of the volume of an expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature; and

[0052] FIG. 2 shows the relative change of the volume of another expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature.

DETAILED DESCRIPTION

[0053] FIG. 1 shows the relative change of the volume V in % of an expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature T in C.

[0054] The expanding wax examined for FIG. 1 was 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-US-00001 TABLE 1 Percentage of Chain Melting the substance Name length temperature/ C. amount/% n-dodecane 12 10 0.0 n-tridecane 13 5 0.1 n-tetradecane 14 6 9.5 n-pentadecane 15 9 6.2 n-hexadecane 16 18 3.9 n-heptadecane 17 21 6.5 n-octadecane 18 28 15.8 n-nonadecane 19 32 9.1 n-eicosane 20 37 10.4 n-heneicosane 21 40 11.2 n-docosane 22 44 9.1 n-tricosane 23 48 6.1 n-tetracosane 24 50 4.4 n-pentacosane 25 54 3.1 n-hexacosane 26 56 1.8 n-heptacosane 27 59 0.8 n-octacosane 28 61 0.3 n-nonacosane 29 64 0.3 n-triacontane 30 65 0.0 Total 98.5

[0055] 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.

[0056] 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.

[0057] 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. 1 shows the values obtained in this way for the rise in temperature (circles) and the reduction of the temperature (squares) of the expanding wax.

[0058] The essential components (percentage of the substance amount >5%) of the expanding wax examined for FIG. 1 have 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.

[0059] As can be seen in FIG. 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 R.sup.2=0.96.

[0060] 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.

[0061] 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.

[0062] FIG. 2 shows the relative change of the volume V in % of another expanding wax of a gas pressure spring according to embodiments of the invention depending on the temperature T in C.

[0063] The expanding wax examined for FIG. 2 was 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-US-00002 TABLE 2 Percentage of Chain Melting the substance Name length temperature/ C. amount/% n-octanol 8 16 0.0 n-decanol 10 7 43.8 n-dodecanol 12 24 0.0 n-tetradecanol 14 38 24.0 n-hexadecanol 16 49 31.4 n-octadecanol 18 59 0.0 Total 99.3

[0064] The relative change of the volume of the expanding wax was determined as described in connection with FIG. 1. In contrast to FIG. 1, an initial temperature of 20 C. was selected.

[0065] The essential components (percentage of the substance amount >5%) of the expanding wax examined for FIG. 1 have 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.

[0066] As can be seen in FIG. 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 R.sup.2=0.98.

[0067] 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.

[0068] 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.

[0069] 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.