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Structure and characteristics of new spoke-type load cells

Keywords: Time:2024-04-02

The spoke-type load cell, as the name suggests, is like a wheel. The spokes are symmetrically distributed in pairs between the hub and the wheel hoop. Most of them have 4 spokes, and the measuring range is mostly 1t~100t. It has low height, good stability, strong resistance to eccentricity and lateral load, and good linearity and repeatability. The elastic element is a symmetrical overall structure, its thermal expansion is basically the same in all directions and its temperature coefficient is low. The upper and lower annular diaphragms are designed to achieve welding sealing and good long-term stability. Through the overload protection gap of about 0.2mm between the wheel hub and the support bottom surface, the overload protection capability can reach 300%. Since traditional spoke-type elastic elements require the use of wire-cut electric discharge technology and equipment during the machining process to form multiple pairs of spokes, the process is more difficult, the production efficiency is low, and the cost is high. In addition, the stiffness design of the wheel hub and tire hoop is improper, and the lag error of the load cell is large and difficult to control.

The new spoke-type load cell, like the traditional spoke-type load cell, is also composed of a hub, a wheel hoop and a wheel spoke. The difference is that the spokes of the new spoke-type load cell are formed by four symmetrical double holes in order to increase the stiffness of the spoke root. The upper and lower surfaces of the wheel spokes are processed into symmetrical arc shapes, so that the wheel spokes become symmetrical strain beams with variable cross-sections. Due to the increased root stiffness of the spokes, the strain stability of the spokes is improved, thereby improving the mechanical properties and long-term stability. In order to improve the linearity and hysteresis performance of the new spoke-type load cell, 8 through holes are symmetrically processed on the wheel hoop, and 8 screws are used to fix the spoke-type elastic element to a base plate with the same diameter and sufficient stiffness.

The new spoke type load cell has the following characteristics:

(1) Has good working characteristics;

(2) High natural frequency;

(3) The output sensitivity is high;

(4) Superior structural symmetry:

(5) Strong resistance to eccentricity and lateral loads;

(6) Good long-term stability;

(7) The creep error is small.

If an internal thread that is concentric and of the same size as the hub threaded hole is processed in the center of the thickened base plate, the application range can be expanded to achieve tensile load measurement or bidirectional measurement of tensile and compressive loads at the same time.

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