RU2150114C1 - Device for velocity measurement - Google Patents

Abstract

FIELD: car velocity measurement. SUBSTANCE: device has housing, which contains rotor, which is designed as multiple-pole magnetic ring, which is mounted on shaft, and magnetic field detector, which is stationary mounted in housing and spaced from multiple pole magnetic ring and separated from it by sealed wall. One end of rotor shaft is mounted in housing by rest rearing. Another end of rotor shaft rests on drive of gear box velocity detector. Drive and multiple pole magnetic ring are separated by compression spring. This design results in possibility to prevent access of dirt from gear box into magnetic field detector. EFFECT: increased reliability of device operations, decreased radial load on floating shaft of rotor due to rest bearing and compression spring. 5 cl, 2 dwg

Description

 The invention relates to measuring equipment and can be used to measure the speed of rotation, including measuring the speed of rotation of the drive of the speedometer of a car’s gearbox, to measure its speed, and can also be used with various information systems, in particular with trip computers.

 A support device is known comprising a fixed element with a touch sensor of a magnetic field, a rotating element, a multi-pole magnetic ring placed on a rotating element, the radial or axial air gap between the rotating magnetic ring and the stationary magnetic field sensor being from 0.1 to 1.5 mm [1].

 The disadvantage of this design is that there is an air gap between the rotating magnetic ring and the stationary magnetic field sensor, into which contaminants can fall, which reduce the reliability of the device.

 A known automobile speed sensor comprising a shaft, a pulse shaper, in the housing of which there is a printed circuit board with electronic circuit elements, an annular multipolar permanent magnet rigidly mounted on the shaft, one end of which is installed in the speed sensor housing and the other in the pulse shaper housing. The housing of the pulse shaper has an annular bore for fixing the board, for example, a vehicle speed sensor according to a utility model certificate [2].

 The vehicle speed sensor of this design is intended for installation on vehicles with a magnetomechanical speedometer, which led to its implementation with a through shaft for connecting to the gearbox speedometer drive. This design does not provide the required degree of sealing of the sensor.

 A known speed measurement sensor comprising a rotor with a multi-pole magnetic ring, a magnetic field sensor mounted on a fixed part with a gap relative to the multi-pole magnetic ring, a screen defining a cavity in which the magnetic field sensor is located and serving as a partition between the multi-pole magnetic ring and the magnetic field sensor [3].

 In this design, the magnetic field sensor is integrated in the bearing ring, in its stationary part, and an annular magnet, consisting of separate sections, is mounted on the rotating part of the bearing.

 Sectional ring magnet is difficult to manufacture. When changing the number of poles, it is necessary to change the number of sections of the ring magnet.

 Such a sensor cannot be installed on the gearbox drive of vehicles having an output shaft in the form of an internal square and an external thread for connecting the shaft and the sensor housing to the drive.

 Also, different types of vehicles require different lengths of the free end of the shaft of the speed measuring sensor for connecting to the gearbox speedometer drive, which leads to the manufacture of various sensor versions.

 The essence of the invention consists in creating a design that is acceptable for various types of vehicles and provides a reduction in radial loads on the supports on the drive side of the transmission speedometer.

 The stated technical problem is solved in that in the inventive speed measurement sensor containing a rotor in the form of a multi-pole magnetic ring and a magnetic field sensor fixedly mounted in the housing with a gap relative to the multi-pole magnetic ring and separated from it by a sealed partition, the multi-pole magnetic ring is mounted on the shaft, one the end of which is mounted on a support bearing, and the transmission speedometer drives the function of the support of the second shaft end, while between the drive and the multi-pole itnym ring arranged compression spring.

 The sensor is equipped with a movable sleeve mounted for movement along the axis of the shaft, and a limiter for moving the movable sleeve fixed in the housing. The diameter of the part of the internal cavity of the housing in which the movable sleeve is in the working position is larger than the outer diameter of the movable sleeve. The movement limiter of the movable sleeve is made in the form of a sleeve. The compression spring is made conical.

 Fixing a multipolar magnetic ring on a shaft, one end of which is mounted on a thrust ball bearing, and using the gearbox speedometer drive as a support for the second shaft end allows the second shaft end to shift in radial directions, thereby relieving the radial loads on the shaft end caused by structural features of articulated elements. And the placement between the speedometer drive of the gearbox and the multi-pole magnetic ring of the spring ensures constant contact of the supporting surfaces of the thrust bearing and prevents the multi-pole magnetic ring from shifting from the sensitivity zone of the magnetic field sensor.

 The use of a movable sleeve and its travel limiter as a support for the second end of the rotor shaft when the speed sensor is not installed on the gearbox speedometer drive allows the use of the same speed sensor in cars that have structural differences between the corresponding articulated parts.

 The implementation of the diameter of the part of the inner cavity of the housing, in which the movable sleeve is in the working position, is larger than its outer diameter and makes it possible to shift the shaft end in radial directions. The implementation of a conical compression spring reduces the dimensions of the device. All this increases the reliability of the device.

The speed sensor is illustrated by drawings, where:
FIG. 1 - General view of the device,
FIG. 2 is a general view of the assembly, the second end of the rotor shaft rests on the gearbox speedometer drive.

 The device is as follows.

 The speed measurement sensor includes a housing 1, in which the rotor 2 is mounted in the form of a multi-pole magnetic ring 3, mounted on the shaft 4. A magnetic field sensor 5 is included in the pulse shaper 6, is fixed in the housing 1, and is sealed from the multi-pole magnetic ring 3 the partition 7. One end 8 of the shaft 4 of the rotor 2 is mounted in the housing 1 on the thrust bearing 9, the role of which is the ball. The support function of the other end 10 of the shaft 4 of the rotor 2 is performed by the gearbox speedometer drive 11 (Fig. 2) (shown by a dotted line). Between the drive 11 and the multipolar magnetic ring 3 there is a compression spring 12. Outside the speed sensor installation, the gearbox speedometer drive 11 (Fig. 1) is supported by the sleeve 13 of the end 10 of the shaft 4 of the rotor 2, which is movably mounted movably along the axis of the shaft 4, and a limiter of its stroke is fixed in the housing 1, for example, in the form of a sleeve 14. Moreover, the diameter of the part of the internal cavity 15 of the housing 1, in which the movable sleeve 13 is in the working position, is larger than its outer diameter.

 The speed sensor works as follows.

 When attaching a speed measuring sensor to the drive of the gearbox speedometer 11 (Fig. 2), the sleeve 13 moves into the internal cavity 15 of the housing 1, coming out of contact with the travel limiter - the sleeve 14. The compression spring 12 ensures that the end 8 of the shaft 4 of the rotor 2 is pressed against the ball- thrust bearing 9 in both the working (Fig. 2) and non-working (Fig. 1) position of the speed sensor. In this case, the magnetic field sensor 5 is always in the range of the multi-pole magnetic ring 3.

 When the rotor 2 is rotated, the end 8 of the shaft 4 is supported by a ball-thrust bearing 9, and its end 10 has some freedom of movement in radial directions, which removes radial loads on the shaft 4. The sleeve 13, pressed by the gearbox speedometer 11 to the internal cavity 15 of the housing 1, rotates with the shaft 4.

Sources of information
1. EP, application N 0250275, G 01 P 3/48.

 2. Application for utility model N 9611391/20 with a positive decision of 10/09/96.

 3. EP, N 0327434 A1, G 01 P 3/48.

Claims (5)

 1. A speed measuring sensor comprising a rotor in the form of a multipolar magnetic ring and a magnetic field sensor fixedly mounted in the housing with a gap relative to the multipolar magnetic ring and separated from it by a sealed partition, characterized in that the multipolar magnetic ring is mounted on a shaft, one end of which is fixed on the thrust bearing, and the speedometer drive of the gearbox performs the function of supporting the second end of the shaft, while a compression spring is placed between the drive and the multi-pole magnetic ring.  2. The sensor according to claim 1, characterized in that it is equipped with a movable sleeve mounted for movement along the axis of the shaft, and a limiter for moving the movable sleeve fixed in the housing.  3. The sensor according to claim 2, characterized in that the diameter of the part of the inner cavity of the housing in which the movable sleeve is in the working position is larger than the outer diameter of the movable sleeve.  4. The sensor according to claim 2, characterized in that the limiter for moving the movable sleeve is made in the form of a sleeve.  5. The sensor according to claim 1, characterized in that the compression spring is conical.

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