Magnetic suspension contact pin type displacement sensor for micro-topography measurement

Abstract

The invention provides a magnetic suspension contact pin type displacement sensor for micro-topography measurement. The magnetic suspension contact pin type displacement sensor comprises a measurement probe, a probe supporting seat, a reading sensor and a signal processing control device. A contact pin is installed at the lower end of a magnetic suspension type feeler lever, the feeler lever is a magnet and arranged in the probe supporting seat, a gap is reserved between the feeler lever and the probe supporting seat, and the probe supporting seat is an electromagnet. The reading sensor corresponds to the measurement probe. The signal processing control device is arranged and connected with the reading sensor and the probe supporting seat. The feeler lever and the contact pin are suspended through the magnetic force effect of the magnetic suspension supporting seat and the feeler lever, a traditional mechanical fixing contact type feeler lever installation method is completely changed, high adaptability of the feeler lever and the contact pin is guaranteed, the feeler lever can only linearly move perpendicular to the surface of a workpiece, non-linear errors of a traditional sensor are fundamentally eliminated, measurement accuracy is greatly improved, the measurement range of the senor is widened, and the magnetic suspension contact pin type displacement sensor is suitable for development of the precision machining technology and better meets the requirements of industrial measurement.

Description

technical field [0001] The invention discloses a stylus type displacement sensor used in a micro-profile measuring device. Background technique [0002] The stylus displacement sensor is the core device of the shape measuring instrument, which is widely used in the industry to measure, detect and characterize the surface shape of on-line and off-line parts. [0003] Stylus measurement is the most basic surface topography measurement method, especially in engineering surface measurement, stylus instruments occupy an extremely important position. It is characterized by large measurement range, high resolution, stable measurement results and good repeatability, so it is often used as a comparison method for the measurement results of other shape measurement techniques; generally speaking, the longitudinal resolution of the stylus displacement sensor is determined by the detection The resolution of the sensing element (typically inductors, capacitors, gratings, etc.) that varie...

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Problems solved by technology

[0007] The support methods of the above two sensors are the most commonly used so far, but in actual use, their measurement accuracy still cannot better meet the needs of industrial production, the reason is that they have the following technical shortcomings:

[0008] 1. In the lever-hinge support mode, there is a gap between the living hinge and the lever. This gap increases with the wear between the lever and the hinge, and it is easy to introduce measurement errors into the measurement results; at the same time, there is a large gap between the lever and the hinge. Frictional force, which is transmitted to the tested sample through the stylus, resulting in a relatively large measurement force, which is easy to damage the tested sample; the displacement transmission adopts a lever design so that the shape change of the tested sample surface cannot be 1:1 is transmitted to the displacement sensing element, and then introduces a nonlinear error in the measurement result

[0009] 2. In the support mode of the elastic element, the elastic element adopts a cantilever structure, and the shape change of the sample surface is transmitted to the sensing element nonlinearly, and then a nonlinear error is introduced into the measurement result; during the shape measurement process, The measurement force varies with the strain of the cantilever elastic element, so the measurement force is uneven and difficult to control. The installation accuracy of the cantilever elastic element is high, and the installation error is easy to introduce large measurement errors to the measurement results.

[0010] The support methods of the two sensors listed above are conventional mechanical contact, that is, the probe rod and the support body are directly connected through a mechanical structure. In fact, the current sensors all use this mechanical contact method, but the contact structure is different. , since the stylus-type micro-profile measurement sensors all adopt the traditional mechanical contact type, it cannot get rid of this large nonlinear error, so the micro-profile measurement accuracy of the traditional stylus-type displacement sensor has been difficult Make an effective breakthrough

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