Patent Application
20100141101
Exemplary embodiments of the invention relate to the art of sensors and, more particularly, to a sensor including an anti-rotation mechanism.
Sensors mounted to rotating components in, for example, motors must be restrained from movement in order to minimize output anomalies or distortions. The sensor must be retained in place over the entire operational life of the motor. Conventional methods of mounting a sensor to a rotating shaft include staking, welding and using a press-fit. Staking a sensor to a shaft requires the application of an impact force. Applying an impact force to a sensor can damage internal components that lead to measurement inconsistencies. Welding a sensor in place, or welding a sensor retainer to hold the sensor also results in measurement abnormalities. Exposing sensors to heat can cause internal damage resulting in data distortion. Using an interference or press-fit creates a deformation in the sensor that can adversely affect internal sensor components. Damage to internal sensor components will lead to undesirable data inconsistencies.
In accordance with an exemplary embodiment, a sensor assembly includes a main body having an outer wall member, an inner wall member, and an intermediate portion. The main body including a central opening defined by the inner wall member. The sensor assembly further includes at least one anti-rotation mechanism formed on the inner wall member. The at least one anti-rotation mechanism member is adapted to deflect radially toward the outer wall member upon engagement with a component to be sensed. Upon deflection, the at least one anti-rotation mechanism fixedly secures the sensor assembly to the component to be sensed.
In accordance with another exemplary embodiment, a method of mounting a sensor to a component to be sensed includes positioning the sensor upon a first end portion of the component to be sensed, urging the sensor from the first end portion toward a second end portion of the component to be sensed, engaging a deflecting element provided on the component to be sensed and an anti-rotation mechanism formed on an inner wall of the sensor and, urging the anti-rotation mechanism radially outward of the component to be sensed. The anti-rotation mechanism gripping the component to be sensed to restrict movement of the sensor.
Additional features and advantages are realized through the techniques of the exemplary embodiments. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features, refer to the description and to the drawings.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
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In accordance with the exemplary embodiment shown, sensor assembly 2 is configured to fixedly mount to a component to be sensed. Towards that end, sensor assembly 2 is fixedly mounted to a shaft 90 having a first or outer diametric portion 92 and an inner splined portion 93. Shaft 90 further includes a second or inner diametric portion having a diameter that is less than outer diametric portion 92. Second diametric portion 96 includes a deflector member 100 which, as will be discussed more fully below, is configured to engage with deflection portions 54 and 74. More specifically, sensor assembly 2 is configured to mount to shaft 90 such that when fully seated, deflector member 100 urges each deflection portion 54 and 74 into deflection zones 51 and 71 respectively. Deflector member 100 causes a non-elastic deformation in each bridge section 50, 70 in order to create an interference-type fit between sensor assembly 2 and shaft 90. More specifically, bridge sections deform or deflect radially between about 0.1 mm and about 0.3 mm. With this particular arrangement, sensor assembly 2 is fixedly secured to shaft 90 without the need for various joining processes such as staking, which would otherwise impart a sharp force to sensor assembly 2 and could damage internal electronic components, welding which requires heat which would also affect internal components and the like. That is, by elastically deforming bridge sections 50 and 70 into respective ones of deflection zones 51 and 71, deflection portions 54 and 74 fixedly engage deflector member 100 ensuring that sensor 2 does not rotate relative to shaft 90.
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At this point, it should be understood that the present invention provides a system for joining a sensor assembly to a rotating shaft without requiring any external forces or heat be generated to sensor assembly 2 during installation. In addition, it should be understood that while shown and described with respect to a sensor for detecting rotation, the sensor assembly described herein can be used in a variety of applications that require minimal contact or disturbance of the sensor during installation. In addition, it should be understood that the amount of deflection of the deflection element can vary depending upon the geometry of the sensor. Finally, it should be understood that the particular shape of the deflection element can vary and include structure that is supported at the deflection zone at two ends or structure that is cantilevered from a single end.
In general, this written description uses examples to disclose exemplary embodiments, including the best mode, and also to enable any person skilled in the art to practice the exemplary embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the exemplary embodiment is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of exemplary embodiments if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
