CN110208567B - Non-contact magnetic fluid rotating speed measuring device, design method and rotating speed measuring method - Google Patents
Non-contact magnetic fluid rotating speed measuring device, design method and rotating speed measuring method Download PDFInfo
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- CN110208567B CN110208567B CN201910452820.7A CN201910452820A CN110208567B CN 110208567 B CN110208567 B CN 110208567B CN 201910452820 A CN201910452820 A CN 201910452820A CN 110208567 B CN110208567 B CN 110208567B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/42—Devices characterised by the use of electric or magnetic means
- G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
- G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
- G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
- G01P3/487—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals delivered by rotating magnets
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Abstract
The invention discloses a non-contact magnetic fluid rotating speed measuring device, a design method and a rotating speed measuring method; the non-contact type magnetic fluid rotating speed measuring device comprises a speed measuring shaft and a speed measuring sleeve which are coaxially arranged, wherein the speed measuring sleeve is sleeved on the speed measuring shaft, and a gap is arranged between the speed measuring shafts; the speed measuring sleeve is provided with a speed measuring cavity, a conductive coating, an induction electrode and magnetic fluid are arranged in the speed measuring cavity, and the conductive coating and the induction electrode are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft; the speed measuring shaft is fixed with a speed measuring magnet which is arranged in the same radial direction with the induction electrode; the speed measuring shaft is used for connecting the rotating speed output end of the object to be measured and synchronously driving the speed measuring sleeve to rotate. And further effectively reduces the load generated by the speed measuring shaft and improves the safety, stability and application range of the speed measuring shaft.
Description
Technical Field
The invention relates to the field of rotating speed measuring devices, in particular to a non-contact magnetic fluid rotating speed measuring device, a design method and a rotating speed measuring method.
Background
The rotation speed measuring device is a measuring device for converting the rotation speed of a rotating object into electric quantity output. The existing rotation speed measuring device belongs to an indirect measuring device, and the common rotation speed measuring device can be manufactured by methods such as machining, electromagnetic machining and mixed machining. According to the signal form, the rotation speed measuring device can be divided into an analog type and a digital type, and the rotation speed measuring device has a wide variety and wide application. The common rotation speed measuring device comprises a photoelectric type, a capacitance type, a variable reluctance type, a tachogenerator and the like.
The rotation speed measurement is mainly carried out by directly transmitting the rotation state in the prior art, but the form causes the tachometer measuring device to generate a certain amount of load and resistance to the tachometer shaft, and the phenomenon is particularly obvious in an electromechanical system. In addition, the bearing bush of the internal measuring device is continuously rubbed under the electrified condition, and is extremely easy to generate heat, and even electric sparks can be generated after abrasion, so that the performance of the electric connector is seriously affected, and dangerous accidents are caused. And most of the current rotating speed measuring devices need to use precise micromachining to manufacture core components of the measuring devices, firstly, the measuring devices need complex microstructures in design; this causes the problem that current rotational speed measuring device stability is poor, the security is poor, application scope is little.
Accordingly, the prior art has drawbacks and needs to be improved and developed.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art, and provides a non-contact magnetic fluid rotating speed measuring device, a design method and a rotating speed measuring method, which aims to solve the problems of poor stability, poor safety and small application range of the rotating speed measuring device in the prior art.
The technical scheme adopted for solving the technical problems is as follows: a non-contact magnetic fluid rotating speed measuring device measures the rotating speed of an object to be measured through an external current detection circuit, which comprises: the speed measuring device comprises a speed measuring shaft and a speed measuring sleeve which are coaxially arranged, wherein the speed measuring sleeve is sleeved on the speed measuring shaft, and a gap is arranged between the speed measuring shafts; the speed measuring sleeve is provided with a speed measuring cavity, a conductive coating, an induction electrode and magnetic fluid are arranged in the speed measuring cavity, and the conductive coating and the induction electrode are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft; the speed measuring shaft is fixedly provided with a speed measuring magnet, and the speed measuring magnet and the induction electrode are arranged in the same radial direction; the speed measuring shaft is used for connecting the rotating speed output end of the object to be measured and synchronously driving the speed measuring magnet to rotate.
Further, the speed measuring sleeve is arranged to be hollow cylindrical, the speed measuring cavity is provided with a first inner surface close to the speed measuring shaft and a second inner surface relatively far away from the speed measuring shaft, the conductive coating is arranged on the first inner surface, the second inner surface is provided with an induction electrode ring, and induction electrodes are arranged on the induction electrode ring at intervals.
Furthermore, the non-contact magnetic fluid rotating speed measuring device further comprises a base, and one end of the speed measuring sleeve is integrally connected with the base.
Further, one end of the speed measuring sleeve, which is far away from the base, is provided with a sealing end cover, and the sealing end cover is in a circular ring shape.
Further, a sealing permanent magnet is further arranged between the speed measuring sleeve and the sealing end cover and close to the first inner surface.
Further, the non-contact magnetic fluid rotating speed measuring device further comprises a rotor, the rotor is arranged between the speed measuring shaft and the speed measuring sleeve, the rotor is fixed on the speed measuring shaft, a gap is arranged between the rotor and the speed measuring sleeve, and the speed measuring magnet is arranged on the surface of the rotor facing the speed measuring sleeve.
Further, a rotor sinking groove is formed in the surface, facing the speed measuring sleeve, of the rotor, the speed measuring magnet is fixed to the rotor sinking groove through a fixed sliding block, and the fixed sliding block is in threaded connection with the rotor.
Further, a shaft end baffle is arranged at the connecting end of the rotor and the speed measuring shaft.
Further, the rotor is detachably and fixedly connected with the speed measuring shaft through a fixed key; the rotor is provided with a first key position sinking groove on the surface contacted with the speed measuring shaft, the speed measuring shaft is correspondingly provided with a second key position sinking groove, and the fixed key is accommodated in the first key position sinking groove and the second key position sinking groove.
The invention solves the technical problem by adopting another technical scheme as follows: a rotational speed measurement method for measuring a rotational speed of an object to be measured, comprising: connecting the rotating speed output end of the object to be measured with the speed measuring shaft of the non-contact magnetic fluid rotating speed measuring device;
after an object to be detected is started, the rotating speed R=N/(m×T) of the object to be detected, wherein N is the number of current pulse signals received by the current detection circuit in a time period T; m is the number of the induction electrodes.
The invention solves the technical problem by adopting another technical scheme as follows: a design method of a non-contact magnetic fluid rotating speed measuring device, which is used in the non-contact magnetic fluid rotating speed measuring device, and comprises the following steps:
s11, preparing magnetic fluid according to nonmagnetic micro-nano conductive particles;
step S12, designing components of the non-contact magnetic fluid rotating speed measuring device according to the rotating speed output end of the object to be measured and the rotating speed measuring environment;
step S13, designing the number m of induction electrodes according to the width and rotating speed measurement requirements of the speed measuring magnet;
s14, designing a base according to the installation environment and the position size, spraying a conductive coating on the bottom of the speed measuring cavity, installing an induction electrode ring, checking the coaxiality of the base and the induction electrode ring, and adjusting the actual effective gap of the speed measuring cavity through the thickness of an induction electrode ring fixing piece;
s15, designing a sealing end cover according to the size of the base, designing an end cover sealing permanent magnet mounting groove on the sealing end cover, mounting a sealing permanent magnet, filling the prepared magnetic fluid mixed with non-magnetic conductive particles into a speed measuring cavity, and testing the leakage-proof property of the magnetic fluid;
and S16, installing a rotor provided with a speed measuring magnet and a magnet stop block with a threaded hole on a speed measuring shaft through key connection and a shaft end baffle, and placing the speed measuring shaft at a testing position corresponding to the induction electrode ring.
Compared with the prior art, the invention provides a non-contact magnetic fluid rotating speed measuring device, a design method and a rotating speed measuring method; the non-contact magnetic fluid rotating speed measuring device measures the rotating speed of an object to be measured through an external current detection circuit, and comprises: the speed measuring device comprises a speed measuring shaft and a speed measuring sleeve which are coaxially arranged, wherein the speed measuring sleeve is sleeved on the speed measuring shaft, and a gap is arranged between the speed measuring shafts; the speed measuring sleeve is provided with a speed measuring cavity, a conductive coating, an induction electrode and magnetic fluid are arranged in the speed measuring cavity, and the conductive coating and the induction electrode are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft; the speed measuring shaft is fixedly provided with a speed measuring magnet, and the speed measuring magnet and the induction electrode are arranged in the same radial direction; the speed measuring shaft is used for connecting the rotating speed output end of the object to be measured and synchronously driving the speed measuring magnet to rotate. And further, the speed measuring load of the speed measuring shaft is effectively reduced, and the safety, stability and application range of the speed measuring shaft are improved.
Drawings
Fig. 1 is a first perspective view of a non-contact magnetic fluid rotation speed measuring device according to the present invention.
Fig. 2 is a second perspective view of a non-contact magnetic fluid rotation speed measuring device according to the present invention.
FIG. 3 is a schematic cross-sectional view of a non-contact magnetic fluid rotational speed measuring device according to the present invention.
Fig. 4 is an enlarged schematic view of fig. 3 a.
Fig. 5 is an enlarged schematic view of B in fig. 3.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clear and clear, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1, the present invention provides a non-contact magnetic fluid rotation speed measuring device 10, wherein the non-contact magnetic fluid rotation speed measuring device 10 is configured to realize synchronous rotation with an object to be measured by externally connecting a rotation output end (not shown) of the object to be measured, and output a current pulse signal by externally connecting a current detection circuit (not shown), so as to calculate the rotation speed of the rotation output end according to the current pulse signal. The non-contact magnetic fluid rotating speed measuring device 10 comprises a speed measuring shaft 11 and a speed measuring sleeve 12, wherein the speed measuring sleeve 12 is sleeved on the speed measuring shaft 11; further, the tachometer sleeve 12 and the tachometer shaft 11 are coaxially arranged, and a gap is arranged between the tachometer sleeve 12 and the tachometer shaft 11; i.e. the tachometer shaft 11 and the tachometer sleeve 12 are not in contact with each other. Further, the speed measuring load and resistance borne by the speed measuring shaft 11 are effectively reduced, direct friction damage, heat generation and even electric spark generation of the speed measuring shaft 11 and the speed measuring sleeve 12 are also effectively avoided, the service life of the non-contact magnetic fluid rotating speed measuring device 10 is effectively prolonged, and the use stability and the use range of the non-contact magnetic fluid rotating speed measuring device are improved; meanwhile, dangerous accidents are effectively avoided, and the safety and the application range of the device are improved.
Referring to fig. 2, 3 and 4 in combination, further, the tachometer sleeve 12 is provided with a tachometer cavity 121, a conductive coating 122, an induction electrode 123 and a magnetic fluid (not shown) are disposed in the tachometer cavity 121, a gap is disposed between the induction electrodes 123 by the conductive coating 122, that is, the induction electrode 123 is not in contact with the conductive coating 122, and the magnetic fluid is filled in the tachometer cavity 121; meanwhile, the conductive coating 122 and the induction electrode 123 are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft 11; specifically, the conductive coating 122 is externally connected to a current input end of the current detection circuit, and the sensing electrode 123 is externally connected to a current output end of the current detection circuit; namely, the conductive coating is an electrode connected with the current detection circuit in the speed measurement cavity 121, and the induction electrode 123 is another electrode connected with the current detection circuit in the speed measurement cavity 121; when the conductive coating 122 is electrically connected with the sensing electrode 123, the external circuit detection circuit generates a current signal; further, the non-contact type magnetic fluid rotation speed measuring device 10 is controlled to output a current pulse signal by controlling the closing and opening of the conductive coating 122 and the sensing electrode 123.
Referring to fig. 5, further, the tachometer shaft 11 is fixed with a tachometer magnet 111, and the tachometer magnet 111 and the sensing electrode 123 are arranged in the same radial direction; the speed measuring magnet 111 can generate a magnetic field and magnetic induction lines in different directions; it can be understood that the tachometer shaft 11 carries the tachometer magnet 111 to rotate, so that the direction of the magnetic induction line of the tachometer magnet 111 is continuously changed; when the tachogenerator magnet 111 and the sensor electrode 123 are radially distributed, the tachogenerator magnet 111 generates a magnetic induction line connecting the sensor electrode 123 and the conductive coating 122. Meanwhile, the magnetic fluid comprises ferrofluid, non-magnetic conductive particles and base fluid, wherein the ferrofluid and the non-magnetic conductive particles are uniformly distributed in the base fluid; the ferrofluid and the base fluid are known as insulators. Further, the non-magnetic conductive particles are self-assembled along the magnetic induction line direction under the action of the magnetic field of the tachogenerator, so as to form a chain structure, and the non-magnetic conductive particles with the chain structure can realize the electrical conduction between the induction electrode 123 and the conductive coating 122, so that the state of the magnetic fluid can be changed by controlling the magnetic field to realize the closing and opening of a circuit, and the non-contact magnetic fluid rotating speed measuring device 10 can further output a current pulse signal.
Specifically, when the tachogenerator 111 and the sensor electrode 123 are radially distributed, the tachogenerator 111 generates a magnetic induction line connecting the sensor electrode 123 and the conductive coating 122, so that the non-magnetic conductive particles are electrically connected with the sensor electrode 123 and the conductive coating 122, and the sensor electrode 123 and the conductive coating 122 are electrically connected, so that the non-contact magnetic fluid rotation speed measuring device 10 outputs a current pulse signal; meanwhile, since the tachometer shaft 11 is connected with the rotation output end of the object to be measured, the tachometer magnet 111 rotates continuously, that is, the direction of the magnetic induction line of the tachometer magnet 111 also changes continuously; further, each time the tachogenerator 111 and the sensor electrode 123 are radially distributed, a magnetic induction line connecting the conductive coating 122 and the sensor electrode 123 is generated, that is, the non-magnetic conductive particles are chained to connect the sensor electrode 123 and the conductive coating 122, the sensor electrode 123 and the conductive coating 122 are electrically conducted once, the non-contact magnetic fluid rotation speed measuring device 10 outputs a current pulse signal, and further the number of current pulse information can be detected to measure the number of rotation turns of the rotation output end of the object to be measured. It should be noted that, the current detection circuit is in the prior art, only the current is detected, and the invention is only applied, but not specifically limited to the current detection circuit.
With continued reference to fig. 4, further, the tachometer sleeve 12 is configured as a hollow cylinder, the tachometer cavity 121 has a first inner surface 125 close to the tachometer shaft 11 and a second inner surface 126 relatively far away from the tachometer shaft 11, the conductive coating 122 is disposed on the first inner surface 125, the second inner surface 126 is provided with induction electrode rings (not shown), the induction electrode rings are disposed with induction electrodes 123 at intervals, the conductive coating 122 coats all the first inner surfaces 125, and the magnetic fluid is filled between the induction electrodes 123 and the conductive coating 122. It can be appreciated that, the sensing electrode 123 includes one or more, when the sensing electrode 123 is set to be a plurality of, evenly distributed between a plurality of sensing electrodes 123 in on the sensing electrode ring, the speed measuring shaft 11 bears the speed measuring magnet 111 and rotates a circle, can make the magnetic fluid turn on a plurality of sensing electrodes 123 and conductive coating 122 electricity in proper order, and then makes the output of non-contact magnetic fluid rotational speed measuring device 10 is equivalent to the current pulse signal of sensing electrode 123 number, and then makes non-contact magnetic fluid rotational speed measuring device 10 can accomplish the accurate measurement of the object rotational speed of treating under the condition of no load, has effectively improved rotational speed measuring stability and security.
In one embodiment, the induction electrode ring is made of a high polymer material and insulating hard plastic; specifically, firstly, an induction electrode 123 and a circuit are plated on the surface of the polymer material, then the induction electrode 123 and the circuit are sealed and bent and attached to the inner surface of an annular fixing piece made of insulating hard plastic, the circuit is connected with the output end of test current, and then the current on the induction electrode 123 is timely output, so that a current pulse signal is generated.
It should be noted that the test sensing electrode ring may also be used to adjust the gap between the tachometer cavity 121, i.e. the sensing electrode ring may also be used to adjust the gap between the sensing electrode 123 and the conductive coating 122; it can be understood that the gap between the velocity measurement cavity 121 is filled with magnetic fluid, and the gap between the sensing electrode 123 and the conductive coating 122 is 50-100 μm; it can be seen that the size of the gap between the sensing electrode 123 and the conductive coating 122 is in negative correlation with the rotation speed of the object to be measured; i.e. the larger the rotation speed of the object to be measured, the smaller the gap between the sensing electrode 123 and the conductive coating 122; meanwhile, the smaller the rotation speed of the object to be measured, the larger the gap between the sensing electrode 123 and the conductive coating 122; of course, when the rotation speed of the object to be measured is small, the gap between the sensing electrode 123 and the conductive coating 122 may be set small. And the gap between the induction electrode 123 and the conductive coating 122 is adjusted through the induction electrode ring, so that the non-contact magnetic fluid rotating speed measuring device 10 can accurately measure the rotating speeds of objects with different rotating speeds, and the measuring stability of the non-contact magnetic fluid rotating speed measuring device 10 is improved.
Preferably, the non-contact magnetic fluid rotation speed measuring device 10 further includes a base 13, one end of the tachometer sleeve 12 is integrally connected with the base 13, an opening (not shown) is provided at one end of the tachometer sleeve 12 away from the base 13, a sealing end cover 14 is provided at one end of the tachometer sleeve 12 away from the base 13, and the sealing end cover 14 is provided in a ring shape; that is, one end of the speed measuring cavity 121 is sealed by the base, and the other end is sealed by the sealing end cover 14; by arranging the sealing end cover 14, the replacement and filling of the magnetic fluid solution in the speed measuring cavity 121 can be realized, and meanwhile, the speed measuring sleeve 12 is convenient to maintain. It should be noted that, the base 13 is made of a non-magnetic material, so as to effectively avoid interference with the magnetic field distribution of the tachogenerator 111 in the tachometer cavity 121, and effectively increase the tachometer stability and accuracy of the non-contact magnetic fluid tachometer 10.
Preferably, a sealing permanent magnet 15 is further disposed between the tachometer sleeve 12 and the sealing end cap 14, near the first inner surface 125. The sealing permanent magnet 15 is used for assisting the sealing end cover 14, enhancing the sealing effect on the magnetic fluid in the speed measuring cavity 121 and preventing the magnetic fluid from leaking.
Preferably, the non-contact magnetic fluid rotation speed measuring device 10 further includes a rotor 16, the rotor 16 is disposed between the tachometer shaft 11 and the tachometer sleeve 12, the rotor 16 is fixed on the tachometer shaft 11, a gap is disposed between the tachometer shaft and the tachometer sleeve 12, and the tachometer magnet 111 is disposed on a surface of the rotor 16 facing the tachometer sleeve 12. Further, the rotor 16 is provided with a circular ring shape, and the inner diameter of the rotor 16 is matched with the outer diameter of the tachometer shaft 11; one end of the rotor 16 is fixed to one end of the tachometer shaft 11 by a fixing key 19.
Specifically, a first key position sinking groove (not shown) is formed on the surface of the rotor 16, which is in contact with the speed measuring shaft 11, a second key position sinking groove (not shown) is correspondingly formed on the speed measuring shaft 11, and the fixed key 19 is accommodated in the first key position sinking groove and the second key position sinking groove; it will be appreciated that the fixation of the rotor 16 to the tachometer shaft 11 may be achieved by providing a fixation key 19; at the same time, the rotor 16 or the tachometer shaft 11 can be replaced and maintained.
Further, a rotor sink (not shown) is formed on the surface of the rotor 16 facing the tachometer sleeve 12, the tachometer magnet 111 is fixed on the rotor sink through a fixed slider 18, and the fixed slider 18 is screwed and fixed with the rotor 16. It should be noted that, the rotor 16 is fixed in contact with the tachometer shaft 11, and the rotor 16 is not in contact with the tachometer sleeve 12; and further, the speed measuring load of the speed measuring shaft 11 is effectively reduced, and the safety of the non-contact magnetic fluid speed measuring device in measuring the rotating speed is improved.
Preferably, a shaft end baffle 17 is arranged at the connecting end of the rotor 16 and the tachometer shaft 11. Namely, one end of the rotor 16 and the tachometer shaft 11, which is far away from the object to be measured, is sealed by the shaft end baffle 17; the shaft end baffle 17 is arranged to be a circular plate and is fixed on the rotor 16 through bolts, and the interference of dust on the rotor 16 and the speed measuring shaft 11 can be effectively avoided through the arrangement of the shaft end baffle 17, so that the application range of the non-contact magnetic fluid rotating speed measuring device 10 is improved.
The invention also provides a rotation speed measuring method for measuring the rotation speed of an object to be measured, which comprises the following steps:
the rotating speed output end of the object to be measured is connected with the speed measuring shaft of the non-contact magnetic fluid rotating speed measuring device;
after an object to be detected is started, the rotating speed R=N/(m×T) of the object to be detected, wherein N is the number of current pulse signals received by the current detection circuit in a time period T; m is the number of the induction electrodes.
Based on the non-contact magnetic fluid rotating speed measuring device provided by the invention, the invention also provides a design method of the non-contact magnetic fluid rotating speed measuring device, which comprises the following steps:
and S11, preparing magnetic fluid according to the nonmagnetic micro-nano conductive particles.
Specifically, the magnetic fluid mainly comprises non-magnetic conductive particles, ferrofluid and base fluid; wherein the particle diameter of the non-magnetic conductive particles is set to be micro-scale or nano-scale; selecting ferrofluid as base liquid according to the physicochemical properties of the nonmagnetic conductive particles; wherein the ferrofluid is an insulator, and the non-magnetic conductive particles are uniformly dispersed and suspended and dissolved in the ferrofluid. Further, the temperature-sensitive insulating ferrofluid with good heat dissipation performance is selected as the ferrofluid; the base liquid can be prepared by selecting solvents such as water, engine oil, hydroxyl oil and the like; and the self-assembly efficiency of the nonmagnetic conductive particles assembled into the chain length L under the design magnetic field strength reaches 70 percent.
And step S12, designing components of the non-contact magnetic fluid rotating speed measuring device according to the rotating speed output end of the object to be measured and the rotating speed measuring environment.
Specifically, whether the rotating speed output end of the object to be measured has the conditions of magnetism, shaft diameter size, rotating speed range, measuring environment and the like, and the components such as a speed measuring sleeve, a speed measuring shaft, a key, a shaft end baffle speed measuring magnet, a threaded hole magnet stop block and the like of the non-contact magnetic fluid rotating speed measuring device are designed.
And S13, designing the number m of the induction electrodes according to the width and the rotating speed measurement requirement of the tachometer magnet.
Step S14, designing a base according to the installation environment and the position size, spraying a conductive coating on the bottom of the speed measuring cavity, installing an induction electrode ring, checking the coaxiality of the base and the induction electrode ring, and adjusting the actual effective gap of the speed measuring cavity through the thickness of the induction electrode ring fixing piece.
Specifically, the actual effective gap of the speed measuring cavity, namely the gap between the induction electrode and the conductive coating, is required to be smaller than the length of the chain assembled by the nonmagnetic conductive particles under the magnetic field intensity. Further, defining the sensing electrode and the sensing electrodeThe gap between the conductive coatings is L 1 Defining the length L of the non-magnetic conductive particles assembled into chains under the magnetic field strength 2 Then the L 2 /4< L 1 < L 2 。
And S15, designing a sealing end cover according to the size of the base, designing an end cover sealing permanent magnet mounting groove on the sealing end cover, mounting a sealing permanent magnet, filling the prepared magnetic fluid mixed with the non-magnetic conductive particles into a speed measuring cavity, and testing the leakage-proof property of the magnetic fluid.
Furthermore, a gap of 0.02-0.20mm is required to be reserved between the sealing permanent magnet and the sealing surface.
And S16, installing a rotor provided with a speed measuring magnet and a magnet stop block with a threaded hole on a speed measuring shaft through key connection and a shaft end baffle, and placing the speed measuring shaft at a testing position corresponding to the induction electrode ring.
And S17, after the primary assembly, a power-on test experiment is required to be carried out, so that the effectiveness of the assembly is ensured.
Compared with the prior art, the invention provides a non-contact magnetic fluid rotating speed measuring device, a design method and a rotating speed measuring method; the non-contact magnetic fluid rotating speed measuring device measures the rotating speed of an object to be measured through an external current detection circuit, and comprises: the speed measuring device comprises a speed measuring shaft and a speed measuring sleeve which are coaxially arranged, wherein the speed measuring sleeve is sleeved on the speed measuring shaft, and a gap is arranged between the speed measuring shafts; the speed measuring sleeve is provided with a speed measuring cavity, a conductive coating, an induction electrode and magnetic fluid are arranged in the speed measuring cavity, and the conductive coating and the induction electrode are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft; the speed measuring shaft is fixedly provided with a speed measuring magnet, and the speed measuring magnet and the induction electrode are arranged in the same radial direction; the speed measuring shaft is used for connecting the rotating speed output end of the object to be measured and synchronously driving the speed measuring magnet to rotate. And further effectively reduces the load generated by the speed measuring shaft and improves the safety, stability and application range of the speed measuring shaft.
It is to be understood that the invention is not limited in its application to the examples described above, but is capable of modification and variation in light of the above teachings by those skilled in the art, and that all such modifications and variations are intended to be included within the scope of the appended claims.
Claims (11)
1. The utility model provides a non-contact magnetic fluid rotational speed measuring device, through external electric current detection circuit measurement object rotational speed that awaits measuring, its characterized in that includes:
the speed measuring sleeve is sleeved on the speed measuring shaft, and a gap is formed between the speed measuring sleeve and the speed measuring shaft;
the speed measuring sleeve is provided with a speed measuring cavity, a conductive coating, an induction electrode and magnetic fluid are arranged in the speed measuring cavity, the conductive coating and the induction electrode are externally connected with a current detection circuit and are coaxially arranged with the speed measuring shaft, and the magnetic fluid comprises nonmagnetic conductive particles;
the speed measuring shaft is fixedly provided with a speed measuring magnet, and the speed measuring magnet and the induction electrode are arranged in the same radial direction;
the speed measuring shaft is used for connecting the rotating speed output end of the object to be measured and synchronously driving the speed measuring magnet to rotate.
2. The non-contact type magnetic fluid rotating speed measuring device according to claim 1, wherein the speed measuring sleeve is in a hollow cylindrical shape, the speed measuring cavity is provided with a first inner surface close to the speed measuring shaft and a second inner surface relatively far away from the speed measuring shaft, the conductive coating is arranged on the first inner surface, the second inner surface is provided with induction electrode rings, and induction electrodes are arranged on the induction electrode rings at intervals.
3. The non-contact type magnetic fluid rotating speed measuring device according to claim 2, further comprising a base, wherein one end of the speed measuring sleeve is integrally connected with the base.
4. A non-contact magnetic fluid rotation speed measuring device according to claim 3, wherein a sealing end cover is arranged at one end of the speed measuring sleeve away from the base, and the sealing end cover is in a circular shape.
5. The non-contact magnetic fluid rotation speed measuring device according to claim 4, wherein a sealing permanent magnet is further arranged between the speed measuring sleeve and the sealing end cover and close to the first inner surface.
6. The non-contact type magnetic fluid rotating speed measuring device according to claim 1, further comprising a rotor, wherein the rotor is arranged between the tachometer shaft and the tachometer sleeve, the rotor is fixed on the tachometer shaft, a gap is arranged between the rotor and the tachometer sleeve, and the tachometer magnet is arranged on the surface of the rotor facing the tachometer sleeve.
7. The non-contact type magnetic fluid rotating speed measuring device according to claim 6, wherein a rotor sinking groove is formed in the surface, facing the speed measuring sleeve, of the rotor, the speed measuring magnet is fixed to the rotor sinking groove through a fixed sliding block, and the fixed sliding block is in threaded connection with the rotor.
8. The non-contact type magnetic fluid rotating speed measuring device according to claim 6, wherein a shaft end baffle is arranged at the connecting end of the rotor and the speed measuring shaft.
9. The non-contact type magnetic fluid rotating speed measuring device according to claim 6, wherein the rotor and the tachometer shaft are detachably and fixedly connected through a fixed key; the rotor is provided with a first key position sinking groove on the surface contacted with the speed measuring shaft, the speed measuring shaft is correspondingly provided with a second key position sinking groove, and the fixed key is accommodated in the first key position sinking groove and the second key position sinking groove.
10. A rotational speed measuring method for measuring a rotational speed of an object to be measured, comprising:
connecting the rotating speed output end of an object to be measured with a speed measuring shaft of the non-contact magnetic fluid rotating speed measuring device according to any one of claims 1-9;
after an object to be detected is started, the rotating speed R=N/(m×T) of the object to be detected, wherein N is the number of current pulse signals received by the current detection circuit in a time period T; m is the number of the induction electrodes.
11. A method for designing a non-contact type magnetic fluid rotation speed measuring device, which is used in the non-contact type magnetic fluid rotation speed measuring device according to any one of claims 1 to 9, characterized in that the method comprises the steps of:
s11, preparing magnetic fluid according to nonmagnetic micro-nano conductive particles;
step S12, designing components of the non-contact magnetic fluid rotating speed measuring device according to the rotating speed output end of the object to be measured and the rotating speed measuring environment;
step S13, designing the number m of induction electrodes according to the width and rotating speed measurement requirements of the speed measuring magnet;
s14, designing a base according to the installation environment and the position size, spraying a conductive coating on the bottom of the speed measuring cavity, installing an induction electrode ring, checking the coaxiality of the base and the induction electrode ring, and adjusting the actual effective gap of the speed measuring cavity through the thickness of an induction electrode ring fixing piece;
s15, designing a sealing end cover according to the size of the base, designing an end cover sealing permanent magnet mounting groove on the sealing end cover, mounting a sealing permanent magnet, filling the prepared magnetic fluid mixed with non-magnetic conductive particles into a speed measuring cavity, and testing the leakage-proof property of the magnetic fluid;
and S16, installing a rotor provided with a speed measuring magnet and a magnet stop block with a threaded hole on a speed measuring shaft through key connection and a shaft end baffle, and placing the speed measuring shaft at a testing position corresponding to the induction electrode ring.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910452820.7A CN110208567B (en) | 2019-05-28 | 2019-05-28 | Non-contact magnetic fluid rotating speed measuring device, design method and rotating speed measuring method |
| PCT/CN2020/082645 WO2020238402A1 (en) | 2019-05-28 | 2020-04-01 | Non-contact magnetic fluid rotational speed measuring device, design method and rotational speed measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910452820.7A CN110208567B (en) | 2019-05-28 | 2019-05-28 | Non-contact magnetic fluid rotating speed measuring device, design method and rotating speed measuring method |
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| CN209946192U (en) * | 2019-05-28 | 2020-01-14 | 南方科技大学 | Non-contact magnetic fluid rotating speed measuring device |
| CN110208567B (en) * | 2019-05-28 | 2023-10-20 | 南方科技大学 | Non-contact magnetic fluid rotating speed measuring device, design method and rotating speed measuring method |
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| FR1398984A (en) * | 1963-04-17 | 1965-05-14 | United Aircraft Corp | Electromagnetic speed detection device |
| US4192189A (en) * | 1978-10-02 | 1980-03-11 | The Bendix Corporation | Rate sensor |
| JPH09257512A (en) * | 1996-03-19 | 1997-10-03 | Yaskawa Electric Corp | Turning angle detecting unit |
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| CN103453896A (en) * | 2013-09-13 | 2013-12-18 | 天津大学 | Magnetic-fluid gyroscope |
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| CN203909058U (en) * | 2014-04-03 | 2014-10-29 | 天津大学 | Magnetofluid compound angular velocity sensor |
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| WO2020238402A1 (en) | 2020-12-03 |
| CN110208567A (en) | 2019-09-06 |
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