氣動撐桿又稱氣彈簧，在背門上既承擔著開閉時的助力且維持舉力不變的作用，又扮演著限位器的角色。在背門開閉過程中，它通過密閉空腔內液氣混合體的相互轉化來提供一個助力作用，同時舉力不變，使得背門可停留在任何位置；當背門開到大位置時，為了防止外板與頂蓋發生干涉，同時限制背門的大開度，使得車門開啟到大位置時停留在原地，不至自動關閉，此時氣動撐桿擔任了限位器的角色。
在氣動撐桿的布置過程中必須注意的問題有：
(1)安裝位置必須正確，不得倒裝；安裝點應盡量靠近過重心的水平線，使后背門受力盡量合理(背門重力不變，靠近后力臂變小，力矩也跟著變小)；
(2)大小合理，有效行程在滿足使用要求情況下盡可能的小，以減小氣動撐桿在背門上的布置空間；
(3)在背門開閉過程中其不應受到傾斜力或橫向力作用，且不得當扶手用；
(4)為確保密封的可靠性，不得破壞活塞桿表面，嚴禁將油漆和化學物質等涂在活塞桿上，也不允許將氣彈簧先安裝在所需位置，后噴、涂油漆；
(5)活塞桿嚴禁向左旋轉，如需要調整接頭方向，只能向右轉動(避免腔內氣體流失)。這點在對氣動撐桿的安裝時，極為重要；
(6)環境溫度一般為-35℃—60℃，在后背門安裝中，要避免和高溫物體(如各類電機等)的接近；
(7)連接點，應轉動靈活，不能有卡阻現象，不允許發生干涉而對氣動撐桿的筒臂造成擠壓。

中譯英：
Pneumatic rod is also called the gas spring, where the back door that can be opened and closed on the power and maintain force constant role, and played a limiter role. In the process of opening and closing the back door, which through the closed cavity liquid / gas mixture into each other to provide a power function, while ensuring the force constant, the back door can be stopped at any position; when the back door to the maximum position, in order to prevent the outer plate and the top cover interference, while at the same time limit back door maximum opening, the door is opened to the maximum position to stay in place, not to shut down automatically, the pneumatic rod is served as a retainer of the role.
In the pneumatic brace layout process must pay attention to the problem:
(1) Installation position must be correct, not flip; the installation point should be as close as possible to the center of gravity of the horizontal line through the back door, stress as reasonable as possible(the back door gravity constant, close to the rear arm becomes small, torque will follow the smaller);
(2) The size of a reasonable, effective stroke in meet the requirement for use case is as small as possible, to reduce aerodynamic bar in the back door arrangement space;
(3) In the back door open and close in the process should not be inclined or horizontal force, and may not be for the handrail;
(4) In order to ensure the sealing reliability, may damage the surface of the piston rod, is strictly prohibited to paint and chemicals on the piston rod, also do not allow the gas spring first installed at desired locations, spray, paint;
(5) The piston rod is strictly prohibited to rotate left, such as the need to adjust the joint direction, can only turn right(avoid intraluminal gas loss). This in the pneumatic support installation, extremely important;
(6) Ambient temperature is -35℃ - 60 ℃, the back door installation, and to avoid high temperature objects(such as various types of motor etc.)close;
(7) Connection point, should be flexible rotation, no blocking phenomenon, is not allowed to interfere in pneumatic rod cylinder arm caused extrusion.
(圖/文http://m.yaohua-power.com/)