A linear drive

Abstract

The invention discloses a linear transmission device, and belongs to the field of medical imaging. The device comprises a motor, a speed reduction device, a clutch and a transmission assembly which are coaxially connected, wherein the transmission assembly comprises a ball screw connected with the clutch and a ball nut, the ball nut is adaptive to the ball screw, the ratio between the lead of theball screw and the diameter of the ball screw is 1.0-2.0, the ball nut can be driven to do linear motion by the ball screw, and when the clutch is powered off, the ball nut can be manually pulled anda scanning bed arranged on the ball nut and loaded with a patient can be driven. With the linear transmission device provided by the invention, low-speed linear motion can be achieved, an end effect of a linear motor having the same function can be effectively prevented on the premise that the scanning bed loaded with the patient can be pulled out of a scanning region, the scanning bed can be enabled to be in a uniform low-speed motion state within the whole scanning range, and the axial uniformity of a scanning image is improved.

Description

technical field [0001] The invention relates to the field of medical imaging, in particular to a linear transmission device. Background technique [0002] In the field of medical imaging, such as PET (Positron Emission Tomography, positron emission tomography) field, CT (Computed Tomography, electronic computer tomography) field, the patient usually lies on the scanning bed, and the linear rotation device is used to install it on it. The scanning table is sent horizontally into the scanning area, and then the patient is scanned and imaged. Different medical imaging fields require different axial movement speeds of the scanning table. For example, in the PET field, the scanning table does not move continuously during system imaging, but stops moving during system acquisition. After acquiring a part, The scanning table moves a preset distance and acquisition continues. However, in recent years, through theoretical research and practice, for the field of PET, the continuous m...

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Problems solved by technology

[0004] First, due to the unavoidable end effect of the linear motor, that is, the magnetic field at the end of the linear motor is distorted, the loss of the motor increases, the thrust decreases, and there are large thrust fluctuations, so that the scanning table cannot be in the scanning area. Stable movement is not conducive to improving the axial uniformity of the scanned image; secondly, due to the need for magnetic isolation when installing the linear motor, it makes installation difficult; thirdly, the cost of the linear motor is relatively high, especially for long-stroke For linear motors, for example, the PET system requires the stroke of the patient's scanning bed to reach more than 1800mm, and the cost of such long-stroke linear motors is very high

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