在 正时皮带或正时链条的传动下，凸轮轴驱动气门在正确的时刻开闭，协作活塞完结进气、紧缩、做功和排气四个进程。由于正时皮带和正时链条在中高速工作时会发作跳动，并且正时皮带在长期使用中会由于皮带的原料和受力，发作拉长、变形发作跳牙导致配气正时的不精确，然后引起车辆费油、无力、爆震等毛病。当跳牙过多时由于气门 过早翻开或过晚封闭还会使气门和上行的活塞磕碰损坏发动机。为了能让正时皮带和正时链条坚持适宜的涨紧度，即不因过松而跳牙也不因过紧而发作损坏，有一个专门的涨紧体系，由涨紧器和涨紧轮或导轨组成。涨紧器供给指向皮带或链条的压力，涨紧轮与正时皮带直触摸摸，而导轨直接与正时链条 触摸，它们在随皮带或链条工作的一起将涨紧器供给的压力施加在其上，使它们坚持适宜的涨紧程度。
under the timing belt or timing chain drive, camshaft drive valve at the right time to open and close, with the piston to complete the intake, compression, work and exhaust four processes. Because of the timing belt and timing chain in high-speed operation will occur when the beating, and timing belt in the long-term use because of belt materials and stress, deformation, occurrence of elongated teeth caused valvetiming inaccurate, causing the vehicle costs oil, weakness, detonation. When the valve is too long or the valve is too early to open or close the valve and the piston will crash the engine damage. In order to make the timing belt and timing chain to maintain the appropriate tension, that is, not too loose because of jumping teeth and not too tight and damage, there is a special tension system, by the tensioner and the tension wheel or rail composition. Tensioner provided to the belt or chain pressure, timing belt tensioner and direct contact, and direct and guide the timing chain contact with them in the belt or chain operation will also provide the tensioner pressure exerted on it, so that they maintain appropriate tension degree.