Tooth meshing with uneven distribution

The invention relates to a is an injection device quantitative injection from the product metering device capable of injecting (1). The injection device comprises a screw rod (2), the screw rod (2) and surface of the tooth part (3) are along the circumferential direction, edge of the threaded the thread of the tooth part (3) is a screw rod (2) circumference of the adjacent teeth along the circumferential direction of the first limit (A1); The injection device is provided with an injection device or a hose, comprising at least one for device shell is connected with a lock according a screw rod (2) meshed (5a and 5b) the first rotating limiting element (5), and provided with a hose, comprising at least one device for rotary sleeve is connected with a lock according a screw rod (2) meshed (5a and 5b) and rotation limiting element (4), the second rotating limiting element (4) to the guide edge of the screw rod vertical direction with a first rotating limiting element (4) is separatedThe groove for the device, the shape or the structure of a rotation limiting element (4) at least lock (5a and 5b), a water the screw rod (2) is symmetric to at least the rotation limiting element (4) rotating smaller than of the first limit (A1) at least lock (5a and 5b) can be in a middle position of the filter.