CN101382440B - Magnetic position sensor with integrated hall effect switch - Google Patents

Abstract

A non-contacting position sensor having primary and secondary sensors detects relative displacement between two objects. The secondary sensor may function as a limit switch detection element in a limit switch circuit, and is positioned to be in the path of magnetic flux not detected by the primary sensor. The primary sensor is positioned in a flux path between sections of a flux gathering pole. A secondary sensor is positioned in a leakage flux path outside the first sensor or may be positioned in a secondary flux path.

Description

Magnetic position sensor with integrated hall effect switch

The application is to be dividing an application of February 18, application number in 2004 are 200480004797.7, name is called the magnetic position sensor with integrated hall effect switch invention the applying date.

MULTIPLE-BLADE

The disclosure require on February 21st, 2003 that submit, wherein all themes by common disclosed U.S. Provisional Patent Application No.60/448,785 right of priority, and enjoy its rights and interests.

Technical field

The disclosure relate generally to a kind of be used to measure two between the object displacement or the device of position, more particularly, relate to a kind of non-contacting position sensor, it has elementary configurable flux source of the primary sensor of being used as and the secondary transducers that is associated with this primary sensor, and these sensors all are used to detect the stem position on the operation valve.

Background technology

Control product flow from food processing factory is kept liquid level in the large-scale oil depot, and industrial processes factory uses operation valve in widespread use.Normally automatic operation valve by as a kind of variable orifice or passage, is used to the management product flow.By mobile inner valve element is valve plug, can accurately control the product volume by valve body.This operation valve is normally automatic, uses topworks and Remote control apparatus, and this Remote control apparatus communicates between process computer and this topworks, with the fluctuations in discharge in the operation valve, thereby realizes the desired control strategy of the operator of this factory.Position transducer plays key effect in keeping accurate process control.

When this process computer issuing command when adjusting flow, this Remote control apparatus must read current valve position, and implements correct corrective action by this topworks.Typical topworks is driven by compressed air source, and this compressed air source is by this Remote control apparatus control.For example, in the spring and diaphragm actuator that on the slide bar valve, uses, affact the variation of the air pressure on large stretch of barrier film, cause the motion or the displacement of this barrier film.What be connected with this barrier film is actuator stem, and this actuator stem is connected to this valve plug again.By changing the air pressure on this barrier film, this Remote control apparatus can directly be located this valve plug, thereby control is by the flow of this operation valve.For Control Flow exactly, where this instrument must always understand valve plug, and where it must move to according to new instruction.By link position sensor between this Remote control apparatus and this actuator stem, can realize this purpose.The output of this position transducer can be directly connected to this Remote control apparatus, thereby stem position feedback is provided, and obtains accurate valve control.

Traditional position transducer, such as pot or other electro-mechanical limit switches, requirement is dynamic or the movable machinery interlock will be moved or displacement inserts this sensor.This electro-mechanical limit switches is installed in the topworks, and when a motor element is positioned at the two ends of half trip or valve rod travel, is triped by this motor element.The signal of output is used to handle relay, solenoid valve from limit switch (perhaps switch), perhaps is used to trigger alarm.For fear of such as in the application of high thrust valve to the damage of control element, this limit switch can be arranged on the appropriate location, so that the motion of valve rod can not surpass its desired length of stroke.

In application, because there is the place of the mechanical vibration caused in turbulent flow, owing in the very short time cycle, cause millions of times execution cycles accumulation, may the dip reliability of sensor of systematic error and instability.Mechanical linkage has contact or wear point equally.Under abominable service condition, on these wear point, instability almost can " cut " these mechanical linkages, thereby valve rod is disconnected from Remote control apparatus.This type is of serious failure can be controlled by destructive valve, must avoid.In order to improve the reliability of sensor, sensor design has been moved toward the non-contacting position detection method.

One type of non-contact sensor is magnetic position sensor.Magnetic position sensor is used to detect two displacements between the object, mainly is by with flux source, and normally magnet is connected on first object, and with sensor, such as hall effect sensor, is connected on second object.This flux source produces magnetic field, by this magnetic field of this sensor.Any motion by one or two objects generation relative displacements produces the different piece of this magnetic field with respect to sensor, thereby changes the output of this sensor.This output can be directly related with the relative displacement between this topworks and the valve rod.

The non-contacting position sensor has very strong usability, and can measure the displacement of various ways.Yet present non-contacting position sensor is subjected to being connected to the restriction of the method on the motor element usually.In Remote control apparatus, have the commercial embodiments of multiple position or feedback transducer, wherein Remote control apparatus still uses " contact " dynamic linkage to insert displacement.A kind of this structure is to use conventional gear, and coming directly will rotatablely move joins on the non-contact magnetically resistance element.Though this magnetoresistive element can be classified as non-contact sensor, this motion is actually by " contact " device conversion, and just as traditional pot based on interlock (linkage-based), the reliability of this motion reduces.

In addition, other non-contacting position sensor from invalid to reconfiguring flux source, thereby be that multi-form displacement measurement (for example, straight line and rotation) provides predetermined output.At people's such as Riggs United States Patent (USP) 5,359,288, people's such as Wolf United States Patent (USP) 5,497,081, and in people's such as Takaishi the United States Patent (USP) 5,570,015, will find the example of above-mentioned form positions sensor.

Other shortcomings of existing non-contacting position sensor, comprise need at least two this limit switch detect the two ends of valve plug travel, be difficult to realize this limit switch, and worry its reliability.In the summary of the invention and embodiment of preferred embodiment hereinafter, with a kind of mode that can overcome whole shortcomings of existing proximity sensor therein of explanation.

Summary of the invention

Position sensor assembly provides the non-contacting position sensor as described herein, is used for detecting exactly two relative displacements between the object, more particularly, is used for accurately measuring the position of the valve plug of operation valve assembly.

Limit switch with high configurable flux source uses a plurality of discrete magnet, and is suitable for measuring straight-line displacement or swing offset.Can achieve this end by the controlling Design of magnet assembly.Each magnet is assembled, producing continuous mixing flux field, thereby produce transformable physical geometry flux source therein.Use comprises the U-shaped pole shoe (pole piece) of two L shaped segmentations, and this pole shoe connects from flux source to Hall effect element the L shaped segmentation of this U-shaped pole shoe or the flux between the primary sensor.

Use secondary transducers in addition, this secondary transducers and this primary sensor collaborative work, and preferably according to working with the proportional mode of this primary sensor.In one embodiment, adopt the U-shaped pole shoe of Hall effect approaching sensor so that two L shaped segmentations each all have asymmetrical Y shape part, to hold the primary and secondary sensor.This primary sensor directly is connected with the end face of U-shaped pole shoe at the first end of this Y shape part.This secondary transducers is connected to the second end of this Y shape part by adapter.

This adapter produces the gap between the second end of secondary transducers and Y shape part, in this article this gap is called air gap.Loss magnetic coupling between this air gap generation and this secondary transducers.By changing the space in this air gap, people can control both flux magnitude of standing of primary and secondary sensor in proportion.When this adapter when preferably electrically insulating material is such as plastics, can recognize that this air gap can also be open space, i.e. air or other materials, and can not change flux by secondary transducers.

In alternative embodiment, this secondary transducers is set to contiguous this primary sensor, and arrange along axis, perhaps be oriented the Hall element of vertical this primary sensor, and be positioned at and the tight position contacting in the bottom surface of U-shaped pole shoe perpendicular to plane, U-shaped pole shoe place.In the view of following accompanying drawing, will show the embodiment that these are different.

Description of drawings

Figure 1A explicit declaration is positioned near the structural drawing of the cross-sectional view of the magnetic sensor the flux source center.

Figure 1B explicit declaration is arranged near the structural drawing of cross-sectional view of the magnetic sensor of the Figure 1A flux source one end.

Fig. 1 C is the figure of diagram corresponding to the magnetic sensor output of Figure 1A.

Fig. 1 D is the figure of diagram corresponding to the magnetic sensor output of Figure 1B.

Fig. 2 A is mounted in the skeleton view that being used in the sliding bar topworks detected the non-contacting position sensor module of valve rod straight-line displacement.

Fig. 2 B is the skeleton view of the whole non-contact sensor assembly among Fig. 2 A, shows interconnecting between flux source and the non-contacting position sensor module.

Fig. 2 C is used for the sensor outer housing of straight line non-contacting position sensor and the skeleton view of sensor module.

Fig. 3 A is the side view of position transducer, shows to comprise a plurality of flux source with discrete magnet of the influence value that is used for the rectilinear path location separately.

Fig. 3 B is the vertical view of position transducer that is used for Fig. 3 A of rectilinear path, and shows lateral attitude and the insertion depth of flux source in sensor module.

Fig. 3 C and 3D combine, and all are the synoptic diagram of diagram one electronic circuit, and this circuit is used for off and on for magnetic sensor provides energy, and the regulating impulse output signal is to produce the simulating signal of using in the Remote control apparatus.

Fig. 4 A is free space figure, is used to illustrate the nonlinear end effects of placing like that as described in the prior art and be used as the single bar magnet of the flux source that is used for the straight-line displacement measurement.

Fig. 4 B is free space figure, is used to illustrate the stack flux field that discrete magnet produced by the discrete magnetic flux source, and assembles the synthetic mixed magnetic field that pole shoe (flux-gathering pole piece) is produced by flux.

Fig. 5 A is the illustrative side view of cylinder-shaped magnet carriage, this carriage is denoted as the equidistant vertical interval of the discrete magnet of the spirally-guided that is used for showing the flux source that is used for 4.5 inch straight line travel position sensors.

Fig. 5 B is the illustrative vertical view that is used for the spirally-guided discrete magnet array of linear position sensors, and this view shows the angular displacement of the discrete magnet in the flux source, and lateral attitude and the insertion depth of this flux source in sensor module.

Fig. 6 is the illustrative perspective view that is connected to the rotational position sensor on the turning axle, and a plurality of discrete magnet that wherein constitute the revolving magnetic flux source are arranged to around this turning axle and become homogeneous angular to distribute.

Fig. 7 A is the illustrative perspective view of the rotational position sensor of end installation, and wherein this cylindrical flux source is rotated between a plurality of branches of flux gathering pole shoe.

Fig. 7 B shows to be used to show that the end of linear output characteristic installs the reference sensitive plane of rotational position sensor and the illustrative end-view of maximum angular displacement.

Fig. 8 is used for according to the sensor outer housing of non-contacting position sensor of the present invention and the skeleton view of sensor module;

Fig. 9 is the planimetric map that the straight line 9-9 in Fig. 8 makes;

Figure 10 is the amplification view of replacement arrangement that is used for the primary and secondary hall effect sensor of non-contacting position sensor;

Figure 11 is that another of primary and secondary hall effect sensor that is used for the non-contacting position sensor replaced the amplification view of arrangement;

Figure 12 is the curve map of magnet carrier stroke to Hall element output (DC voltage form), show the primary and secondary hall effect sensor of being arranged according to an embodiment, corresponding to the relative output of diverse location along the stroke of the converter,linear of the typical stroke of representing valve rod or valve plug, be the magnet carrier stroke to elementary Hall element (Allegro 3516 LUA) and with the output of the secondary Hall element of the end-to-end placement of elementary Hall element, second sensitive element is the air gap outside between magnetic pole just in time, magnet array is 2.5 inches, 14 magnet #A14-6 version 1.3 calibrations; And

Figure 13 is the synoptic diagram of system representation, is wherein detected, analyzed the voltage output of primary and secondary hall effect sensor by processor, compares with the data in being stored in its storer, and output signal can be offered controller from this system.

Embodiment

In order to understand the advantage of position transducer described herein, how to turn round and measure displacement on the operation valve thereby be necessary to understand the element of position transducer and they.Though described preferred embodiment has been explained the displacement measurement that relates to operation valve, those skilled in the art will recognize that the correlativity of using with other displacement measurements equally.Turn to accompanying drawing and, shown the critical component of this non-contacting position sensor at first with reference to Figure 1A.

In Figure 1A, sensor 5 is disposed near the flux source 8.As everyone knows, flux source 8 produces the continuous three-dimensional flux field, and this flux field is surrounded flux source 8 and sensor 5 fully.Then, sensor 5 is a kind of devices that produce and surround magnetic field 10 proportional electric signal of sensor 5.Such as is known to persons skilled in the art, the intensity in the magnetic field of being detected 10 changes with respect to the position in the magnetic field 10.Therefore, shown in the chart among Fig. 1 C, sensor 5 all will produce corresponding the variation with respect to the relative position in magnetic field 10 or any variation in the displacement in the output of sensor 5.Can utilize this relation to make the non-contacting position sensor.

In the application of non-contacting position or displacement measurement, sensor 5 and flux source 8 all are installed in two machineries independently on the object (not shown).There is not to use mechanical linkage dynamic or motion that the relative displacement between the flux source 8 is directly coupled in the sensor 5.Refer again to Figure 1A, the relative position of sensor 5 and flux source 8 makes sensor 5 be arranged in the position at close flux source 8 centers, has the displacement of representing with D1.Corresponding chart shows the output of using the sensor 5 that the V1 for displacement D1 represents in Fig. 1 C.In Figure 1B, this displacement is changed to new position, represents with D2, and sensor 5 is arranged near the end of flux source 8.In Fig. 1 D, corresponding chart shows the variation among the sensor 5 output V2, should be directly related with the change in location of sensor 5 in the magnetic field 10 that is produced by flux source 8.These of sensor 5 output signals change, and are used as the independently direct measurement of the displacement between the object of these two machineries.Be connected to the electronic circuit (not shown) on the sensor 5, be used for handling the output signal of the sensor 5 that uses in the operation valve application that describes in detail more hereinafter.

With reference now to Fig. 2 A,, position transducer is shown as with the sliding bar topworks 20 of the automatic control that is used for operation valve and is connected.Sliding bar topworks 20 is applicable to rectilinear motion (i.e. moving along straight line).The skeleton view of Fig. 2 A shows the magnetic sensor assembly 11 and the flux source 18a (carrying out more detailed demonstration in Fig. 3-7) of this position transducer, is how to be installed in independently between sliding bar topworks 20 and the Remote control apparatus 19 (the only modular substrate of display remoting instrument).

As everyone knows, sliding bar topworks 20, Remote control apparatus 19 and operation valve (not shown) combine and form valve module 23.Installation component 14 is connected to flux source 18a on the rod connector 27.Installation component 14 is made of installing plate 15a and alignment sheets 15b.Use rod connector bolt 16a and 16b that rod connector 27 is connected between actuator stem 17 and the valve rod 21.

At United States Patent (USP) 5,451, the general operation of the typical valve module that is not equipped with this position sensor is described in 923, this patent is transferred to Fisher Controls International company, and it is incorporated in this as a reference.As everyone knows, when Remote control apparatus 19 received the order of moving this valve plug, pressurized air was directed to sliding bar topworks 20, and actuator stem 17 will produce motion.Any displacement of actuator stem 17 all will make flux source 18a produce variation relatively with respect to the position of sensor module 11.This change in location changes this sensor output.This output signal is sent in the Remote control apparatus 19 and handles, thereby produces the accurate control to the valve plug (not shown).Fig. 2 B shows the skeleton view of linear position sensors 30a.Flux source 18a and sensor module 11 closely closely arrange, thereby magnetic field 10 (Figure 1A and Figure 1B) is connected on the sensor module 11 fully, but do not come in contact in operational process.

With reference now to Fig. 2 C,, sensor module 11 is installed in the sensor outer housing 22.Sensor outer housing 22 provides flux to assemble the position alignment (illustrating in further detail hereinafter) of pole shoe 32 and magnetic sensor 35.By support 38 and two screw 24a and 24b, magnetic sensor 35 and flux are assembled pole shoe 32 remain in the sensor outer housing 22.In addition, be electrically connected, and can be fit to the industrial limitations that is used for the operation of inherent safety and blast protection in the hazardous environment well-known to those skilled in the art by sensor outer housing 22 being integrated directly in the Remote control apparatus 19, simplifying.Sensor outer housing 22 is by aluminium or any nonmagnetic substance manufacturing that other is fit to, and is suitable for holding sensor module 11.

With reference now to Fig. 3 A and Fig. 3 B,, with flux source 18a (Fig. 3 A) and the sensor module 11 (Fig. 3 B) that goes through in the preferred embodiment.In the preferred embodiment, flux source 18a designed to be used within its whole range of displacement measurement and measures rectilinear path, and linear output signal is provided.For example, 10% variation will produce corresponding 10% variation in the displacement in the signal of sensor of position.All changes in the position transducer output all with displacement in be varied to direct ratio.This linearity output relation is in service very important Remote control apparatus.Measure by the direct proportion that produces displacement, not needing just can provide position feedback by the extra process of Remote control apparatus 19 or sensor electronics circuit 13 (Fig. 3 C and 3D).

Independently a plurality of or discrete cylinder-shaped magnet 50-72 is installed in the rectangle carriage 41, is used for producing flux source 18a.The preferred material that is used for carriage 41 is non magnetic, such as aluminium or plastics.In the preferred embodiment, 23 discrete magnet 50-72 are disposed in the carriage 41, are used to produce the linear array that can measure about 4.5 inches rectilinear path.Discrete magnet 50-72 is preferably made by alnico (ALNICO) 8H, and vertically or horizontally.In one embodiment, use epoxy resin, such as the Minnesota State, 2214 structural adhesives (Structural Adhesive) that the 3M company in Sao Paulo makes are installed in magnet 50-72 in this carriage.Each discrete magnet all approximately is that diameter is 0.1875 inch, and length is 0.1875 inch.Each magnetic blow out centre is approximately 0.25 inch in vertical direction to the spacing at center, and about 4.5 inches displacement measurement is set on the core of this array.Carriage 41 provides the mechanical registeration of this magnet array, and uses installation component 14 to be directly connected on the rod connector 27, uses rod connector bolt 16a and the 16b shown in the prior figures 2A, and making-up unit 14 is connected on the rod connector 27.

As skilled in the art to understand, the dimensional tolerence that produces in Remote control apparatus 19 is installed in process in the topworks 20 is stacked, requires to carry out instrument calibration before valve module 23 operations.By along this vertical stroke axis with flatly providing coarse position correction in the plane perpendicular to this longitudinal axis, help this instrument calibration.Be different from the prior art interlock of directly motion being coupled to sensor, the installing plate 15a of installation component 14 and alignment sheets 15b are static, and adjustment only is provided in installation process.In Fig. 3 B, further specify the horizontal aligument of flux source 18a and sensor module 11.

Vertical view shown in Fig. 3 B clearly illustrates the U-shaped flux gathering pole shoe 32 of sensor module 11.Flux is assembled pole shoe 32 and is comprised two by the high-penetrability material, Pennsylvania preferably, the HyMu " 80 " of the annealing of the special technology company of Li Dingkapeng

The L shaped segmentation 33a and the 33b that make, and be arranged to mirror-inverted each other.L shaped segmentation 33a and 33b combine in the bottom, have the gap that is suitable for holding magnetic sensor 35, and each L shaped segmentation 33a and 33b are arranged in position near magnetic sensor 35.The square cross section size of each L shaped segmentation 33a and 33b all is approximately 0.15 inch.Preferably, each the L shaped segmentation 33a and the 33b degree of depth all are approximately 1.25 inches, and cross this bottom and have 0.445 inch, thereby form about 1.25 inches of the degree of depth, width is the U-shaped of 0.89 inch physical dimension.In the preferred embodiment, magnetic sensor 35 is Hall effect elements of Allegro 3515, other forms ofly comprises but is not the magnetic sensor that is limited to the Hall effect element of Allegro 3515 but can or use in addition equally.

Handle the output of magnetic sensor 35 by electronic circuit 13 (Fig. 3 C and 3D).Electronic circuit 13 is provided with interface between magnetic sensor 35 and Remote control apparatus 19.As shown in Fig. 3 C, pair of connectors J1 and J2 be received power from industrial standard 4-20mA current coil.As skilled in the art to understand, the power that is used for magnetic sensor 35 and electronic circuit 13 can produce from adjusting circuit, this adjusts circuit passive element R5, R6, R7, R10, R11, R12 and C5, and from the California, the little power consumption voltage reference diode of the LM285 of the National Semiconductor of Santa Clara U2 designs.Be displayed in Table 1 the value/sign of other element among these elements and Fig. 3 C and the 3D.

Intermittently be these circuit supplies, the power consumption of can deperm sensor 35 and electronic circuit 13.Magnetic sensor 35 is connected on this electronic circuit by connector J3, and locates " power switch " or be subjected to pulse action at about 200 hertz by multichannel fet (FET) Q2.As skilled in the art to understand, embedded controller U1, the Arizona State, the PIC12C508A of the microchip technology company of Phoenix, and passive element R1, Y1, C1 and C2 are provided for the timing and the control of pulsing operation.Must carry out interpolation or reconstruction from the pulse output signals of magnetic sensor 35 outputs, can be thereby produce by the simulating signal of Remote control apparatus 19 processing.FET Q1, operational amplifier U3A (Fig. 3 C), and a plurality of passive element R2, R8, R13, R14, C3, C6 and C7 produce sampling and holding circuit, are used for reconstructed analog signal.Operational amplifier U3B and a plurality of passive element R3, R4, R9 and C4 adjust (promptly adjusting gain and skew) and filter reconstructed analog signal, thereby produce final output signal.By connector J4, final output signal or position displacement measurement are transported to (Fig. 3 C) in the Remote control apparatus 19.At last, test connector J5 can provide test signal for the diagnostic assessment that is used for magnetic sensor 35 and electronic circuit 13.

Element	Value/sign
		R1	100KΩ
R2	634KΩ
		R3	178KΩ
R4	86.6KΩ
		R5	665KΩ

R6	24.3KΩ
		R7	51KΩ
R8	221KΩ
		R9	1MΩ
R10	665KΩ
		R11	15KΩ
R12	60.4KΩ
		R13	2MΩ
R14	1MΩ
		C1	5.1pFd
C2	5.1pFd
		C3	0.47μFd
C4	18pFd
		C5	47μFd
U1	PIC12C508A
		U2	LM285BYM
U3	OP281
		Y1	131KHz
Q1	BSS138
		Q2	BSS138
J1	CONN0611

J2	CONN0611
		J3	CONN0411
J4	CONN0411
		J5	CONN0611

Table 1

Continue with reference to figure 4B, flux is assembled the magnetic field 10 that pole shoe 32 trapped flux amount source 18a produce, and with this flux guide magnetropism sensor 35, will illustrate in further detail this hereinafter.Flux source 18a is installed to be and is approximately perpendicular to sensor module 11, and the interior pin physics that any so relative horizontal shift can not cause flux source 18a and flux to be assembled on the pole shoe 32 contacts.The engagement that flux source 18a and U-shaped flux are assembled the opening of pole shoe 32 is approximately 0.3125 inch.0.2 inch the air gap of being approximately that is arranged in flux source 18a both sides is arranged in sensor module 11 symmetrically with flux source 18a.

Each discrete magnet 50-72 produces magnetic field.As everyone knows, the shape in described magnetic field and density are directly related with a plurality of factors.Two in these factors is the induction of magnet and the interaction of magnet and external magnetic field.In order to understand the characteristic feature of flux source 18a better, hereinafter above-mentioned factor will be described in further detail.

The induction of magnet is the direct measurement of its inherent magnetic intensity, and can control in manufacture process or sequencing.As everyone knows, for given magnet physical geometry, the increase in its induction will produce corresponding increasing in magnetic intensity and its magnetic density.By the induction of control discrete magnet, can control its flux density (i.e. flux magnitude in given volume), and therefore can control its magnetic field.Equally, not to combine with the magnetic field that discrete magnet produces by any additional or external magnetic field that discrete magnet produces.The polarity of complementary field and density can " additivity ground " increase or reduce around discrete magnet magnetic field on every side.The magnetic circuit usability of this explanation should control and external magnetic field between interaction produce programmable flux source.

As proof of the prior art, when being used for the whole length of displacement measurement use magnet, single bar magnet can be difficult.As shown in Fig. 4 A, in the application of single bar magnet, the polarised direction or the orientation of magnetic pole are parallel to stroke directions.Polar orientation is provided with the magnetic field 130a and the 130b of high concentration near magnetic pole.In these dense flux regions, the repulsive force between the magnetic flux line produces extreme nonlinearities change in magnetic field.If single bar magnet will be used to displacement measurement, then need to carry out special processing, thereby produce linear output by the sensor module electronic circuit.In addition, it is about 75% that the length of magnet can increase, thereby get rid of nonlinear end effects, but this method has unnecessarily increased cost, and because the increase of physical length has limited the application of position transducer.In this preferred embodiment, magnet flux source length can with the maximum displacement that will detect about equally, and do not need output signal is carried out special processing.

Fig. 4 B is the free space figure that only uses the preferred embodiment of seven discrete magnet 50-56, is used to illustrate the magnetic field 110-116 that mutually combines and produce bigger mixed magnetic field 10.Following magnetics principle general description the relation between a plurality of discrete magnet.Shown in Fig. 4 B, individual magnetic 110-116 not only surround generation directed discrete magnet 50-56, and be provided for the crossing magnetic flux line of adjacent magnets.Combine to the flux regions additivity of stack, be used to produce the predetermined magnetic field 10 of the bigger whole flux source of qualification.In a preferred embodiment, the pole axis of each discrete magnet 50-56 vertically points to the direction of relative motion, to help " stack " magnetic field continuously.By induction or the intensity of controlling each discrete magnet 50-56, and it is arranged to linear array, 110-116 additivity ground, discrete magnetic field interosculates, and can produce the flux source able to programme of being scheduled to magnetic field 10 thereby produce.

As indicated above, each discrete magnet all has special magnetic associated therewith " energy " or induction amount.Physics magnetic volume, magnet geometry and ferromagnetic material characteristic all define in magnet to have how much magnetic energy.Know that as those skilled in the art institute 0 induction of each discrete magnet can use traditional magnetic processor to design or calibrate, such as the Indiana State, the model that the magnetic equipment company of Indianapolis produces is 990C's

When using model as 990C's

The time, needs are considered all characteristics of above-mentioned magnet.The table 2 that illustrates provides the influence value that is used for the linear array shown in Fig. 3 A hereinafter.

The magnet number	Index (Gauss)
		50	465.6
51	465.6
		52	344.5
53	288.7
		54	258.4
55	218.8
		56	186.2
57	142.0
		58	121.1
59	76.8
		60	46.6
61	0
		62	-46.6
63	-76.8
		64	-121.1
65	-142.2
		66	-186.2

67	-218.8
		68	-258.4
69	-288.7
		70	-344.5
71	-465.6
		72	-465.6

Table 2

As described and illustrated in Table 2, the influence value of magnet sequence has periodic changes, thereby produces the magnetic field 10 of flux source 18a.Discrete magnet 61 is disposed in the geometric center of array, and is designed to 0 Gauss, thereby provides magnetic null for absolute reference in instrument calibration.In addition, measure for absolute displacement is provided, discrete magnet 50-72 has opposite polarity in the both sides of magnetic null.Polarity difference detects by electronic circuit 13 (not shown in Fig. 4 B), and by Remote control apparatus 19 with it as Absolute position measurement.As everyone knows, in the value of table 2, opposite mathematical symbolism change in polarity.Usually, the relative displacement on the expression magnetic null, negative value is represented the relative displacement under the magnetic null.Though preferred embodiment has been explained the position transducer with linear output relation, it should be understood that the inherent programmability of flux source can provide multiple position sensor output signal travel relationships, and do not change the sensor module electronic circuit.Equally, the unique property in discrete magnetic flux source provides sufficient adaptability for multi-form displacement measurement.In the alternative embodiment of being explained this adaptability will be described in further detail hereinafter.

In another embodiment that straight line is used, in flux source, reorientate discrete magnet and control interaction.As indicated above, preferred embodiment relies on the induction of design adjacent discrete magnets to produce predetermined output signal.Refer again to Figure 1A-1D, the physical location in the magnetic field determines the measured intensity in this magnetic field.Similarly,, the performance intensity of discrete magnet can be controlled, therefore its interaction can be controlled by between adjacent magnets, producing space and distance.

Fig. 5 A is the side view of another embodiment.The discrete magnet 50-72 of flux source 18b equidistantly arranges along the longitudinal axis 46 of carriage 42 once more.The diameter of discrete magnet 50-72 is approximately 0.125 inch, and length is 0.462 inch.Carriage 42 is suitable for holding the discrete magnet 50-72 with the center to center spacing that is approximately 0.25 inch.By the longitudinal axis 46 spiralitys ground guiding or the rotation discrete magnet 50-72 around flux source 18b, the interaction that comes controlling magnetic field.As everyone knows, by increasing the spacing of leaving magnet in any direction, the apparent intensity of magnet will be reduced.In this alternative embodiment, provide around the longitudinal axis accurate angular displacement between adjacent magnets, control the interaction between the adjacent magnetic field.In this alternative embodiment, the sensor module that describes in detail in sensor module 11 (not shown) and the preferred embodiment is identical.Therefore, by the computer azimuth of discrete magnet 50-72, can produce predetermined output signal.

Fig. 5 B is the vertical view that is used for the spiral sensing flux source 18b of linear position sensors.This view shows the rotary reference plane 126 that is used for discrete magnet 50-72.Flux source 18b approximately assembles first and second L shaped segmentation 33a of pole shoe 32 and the core between the 33b at flux.The table 3 that illustrates provides the rotation angle example that requires to obtain substantially linear output from sensor module 11 (not shown) with the discrete magnet 50-72 that all is designed to about 457 Gausses hereinafter.

The magnet number	Rotation angle (degree)
		50	10
51	43
		52	70
53	71
		54	71
55	74.5
		56	79
57	80
		58	82
59	85
		60	89
61	90
		62	91
63	95
		64	98
65	100
		66	101
67	106
		68	109
69	109
		70	110
71	137

72

170

Table 3

Another embodiment of display position sensor among Fig. 6.Similar techniques structure rotation non-contacting position sensor 30b in use and the preferred embodiment.15 discrete magnet 50-64 are arranged in the quadrant bracket 43 that homogeneous angular is distributed as 6 °.This quadrant bracket is arranged vertically on turning axle 47, to produce revolving magnetic flux source 18c.In addition, fan 43 is preferably made of aluminum.By rotation installation component 79, revolving magnetic flux source 18c is directly connected on the turning axle 75.Flux is assembled the L shaped segmentation 33a and the 33b of pole shoe, magnetic sensor 35, and discrete magnet 50-64 is identical with above-mentioned explanation.The table 4 that illustrates hereinafter is for the revolving magnetic flux source 18c shown in Fig. 6 provides influence value.

The magnet number	Demarcate (Gauss)
		50	465.6
51	226.3
		52	179.3
53	155.0
		54	110.3
55	82.9
		56	36.8
57	0.0
		58	-36.8
59	-82.9
		60	-110.3
61	-155.0
		62	-179.3
63	-226.3
		64	-465.6

Table 4

Rotational position sensor 30b shown in Fig. 6, the controlled calibration of the induction by each discrete magnet 50-64 provides the linear relationship between the output of rotating distance and sensor.By 90 ° rotation, provide linear output operation characteristic.

Principle described herein can be applied to having the rotational position sensor 30c of the linear range of operation of prolongation equally.Use with above with reference to L shaped segmentation 33a and the 33b and the magnetic sensor of the described identical flux gathering pole shoe 32 of figure 2C, can be used for the flux source of position transducer with single cylinder bar magnet 39 conducts.As shown in Figure 7A, rotation sensor 30c is designed to the output that changes with linear mode can be provided.Cylinder-shaped magnet 39 is assembled between the first and second L shaped segmentation 33a of pole shoe 32 and the 33b at flux and is rotated, and is the output signal of linearity to provide substantially.By correct select magnet length, can obtain the maximum linearity.Assemble pole shoe 32 with respect to flux, the optimal length of cylinder-shaped magnet 39 is to be essentially flux to assemble 2/3 of gap width between the L shaped segmentation of pole shoe 32.For example, the flux that uses inner width to be approximately 0.59 inch preferred embodiment is assembled pole shoe 32, and cylinder-shaped magnet 39 will have and be approximately 0.385 inch length.In this alternative embodiment, the diameter of cylinder-shaped magnet 39 is approximately 0.1875 inch.As shown in the figure, carriage 44 is connected to cylinder-shaped magnet 39 on the turning axle 75.Carriage 44 is suitable for the axis 49 around turning axle 75, is connected on the cylinder-shaped magnet 39.In addition, cylinder-shaped magnet 39 is inserted into flux and assembles in the opening of pole shoe 32 about 0.3125 inch.

As shown in Fig. 7 B, provide linear output operation characteristic by 110 ° rotations, wherein, this rotation is to center on plane 119 symmetric arrangement of first and second L shaped segmentation 33a of five equilibrium flux gathering pole shoe 32 and 33b.Five equilibrium plane 119 meets at right angles with the detection plane 118 of magnetic sensor.

Above shown and illustrated the multiple executive mode of the position transducer that uses single hall effect sensor.Can be described hereinbefore and shown in technology and structure in carry out multiple adjustment and change.For example, the magnetic shunt path of making by the ferromagnetic powder material can be set near or surround the position of each discrete magnet fully, to reduce its magnetic field selectively, therefore control its effect on follow-up magnet.In addition, can between each magnet, use inhomogeneous spacing equally, perhaps use variable magnet length.

In addition, shown in the embodiment among Fig. 8-11, secondary hall effect sensor can be added to the U-shaped flux that uses in single Hall effect noncontact proximity transducer assembles on the pole shoe.Referring to accompanying drawing 8, sensor module 200 is installed in the sensor outer housing 212.The U-shaped flux is assembled pole shoe 214 and is arranged regularly by sensor outer housing 212.Explanation is such more fully as mentioned, and the U-shaped flux is assembled pole shoe 214, comprises the first L shaped segmentation 216 and the second L shaped segmentation 218, and is disposed in the position of closely adjacent flux source.Flux source can adopt, and for example contains the form of the rectangle carriage (as shown in Fig. 3 A) of a plurality of discrete cylinder-shaped magnets, uses this carriage can help to detect by the sensor module 210 with linear position and stroke.Replacement arrangement for flux source is possible equally.For example, for the ease of detecting position of rotation and stroke, flux source can adopt the form of fan-shaped (as shown in Figure 6) that contain a plurality of discrete magnet, preferably is arranged as homogeneous angular and distributes.

Shown in the best among Fig. 9, in sensor outer housing 212, the first L shaped segmentation 216 and the second L shaped segmentation 218 stop in the position of asymmetrical Y shape part 220,222 respectively.Asymmetrical Y shape part 220,222 has first end 224,226 separately respectively.Elementary hall effect sensor 228 is disposed in the U-shaped flux to be assembled between the first end 224,226 of Y shape part 220,222 of the first and second L shaped segmentations 216,218 of pole shoe 214.Preferably stigmatic with the surface 238 of L shaped segmentation 218 contacted elementary special sensors 228.

Each asymmetric Y shape part 220,222 also has the second end 230,232 respectively.First end 224,226 and the second end 230,232 all are disposed in the head end of each Y shape part 220,222.Sensor outer housing 212 preferably also provides adapter 234, and this adapter is made such as plastics by electrically insulating material, but magnetic flux can pass this adapter.Shown in the best among Fig. 9, secondary transducers 236 and adapter 234 all are disposed between the second end 230,232 of asymmetric Y shape part 220,222.Similar with primary sensor 228, secondary transducers 236 is hall effect sensors, in asymmetric Y shape part 220,222 first and second ends 224,226, be furnished with at least one sensitive element on 230,232 the normal direction, thus vertical with the flux directions of U-shaped flux gathering pole shoe 214 generations.

By asymmetric Y shape part 220 is provided, 222, make primary sensor 228 be positioned at first and second ends 224, between 226, make secondary transducers 236 with adapter 234, be positioned between first and second ends 230,232, the part flux can be avoided effectively from primary sensor 228, and is detected by secondary transducers 236.Secondary transducers 236 can be used as the limit switch element in the limit switch circuit, it has the reliability of increase on whole single-sensor non-contacting position sensor, and helps equally avoiding at two limit switches of the two ends of valve rod travel needs.

Advantageously, adapter 234 produces air gap between the second end 230,232 of secondary transducers 236 and asymmetric Y shape part 220,222, produces therein to be connected with the lossy magnetic of secondary transducers 236.By controlling the space in this air gap, and other element of magnetic circuit, such as pole end piece surface area, can control the flux magnitude of passing through in primary sensor 228 and the secondary transducers 236 respectively.

Have been found that about 0.13 inch air gap provides the output of 40% to 50% secondary transducers 236 of the output of primary sensor 228, this output is the ideal output of the secondary transducers when being used as limit switch.In addition, by the size of change adapter, the size of air gap, perhaps the material of adapter all will influence the relative output of primary sensor 228 and secondary transducers 236.Therefore, mainly be used as position transducer in primary sensor 228, and secondary transducers 236 is used as in those application of limit switch, preferably, the U-shaped flux of the ratio secondary transducers 236 bigger number percents that primary sensor 228 stands is assembled the magnetic flux that pole shoe 214 produces, so select each size and material, thereby produce desired result.

In other embodiments, can secondary transducers 236 be set, will not need to change the end that the U-shaped flux is assembled the L shaped segmentation 216,218 of pole shoe like this with respect to primary sensor 228.Referring now to Figure 10,, primary sensor 228 is shown as between the surface 238 of the end that is positioned at L shaped segmentation 216,218 and primary sensor 228, and surface 238 contacts with L shaped segmentation 218, and preferably stigmatic.In this embodiment, secondary transducers 236 is arranged to next-door neighbour's primary sensor 228, and the end of primary and secondary sensor 228,236 preferably contacts like this.

For secondary transducers is stood as the flux among the above-mentioned embodiment, replacement is from 228 fens circulatioies of primary sensor, the secondary transducers 236 of Figure 10 embodiment (secondary transducers 236 of the alternative embodiment again among Figure 11 is identical with it) detects the leakage flux near primary sensor 228., secondary transducers 236 need be arranged in the leakage flux path, wherein this path is positioned as close to primary sensor 228 for this reason.

The Hall effect sensitive element 240,242 of primary sensor 228 and secondary transducers 236 is arranged in order respectively, and perpendicular with the end of L shaped segmentation 216,218.Because the end of primary sensor 228 and secondary transducers 236 contacts, so advantageously, sensitive element 240,242 can be approaching as much as possible each other with about 0.112 inch distance, like this, when elementary and secondary transducers part 228,236 are disposed in the same plane, by the sensitive element 242 of secondary transducers 236, the leakage flux that maximizes basically near primary sensor 228 detects.

Turn to Figure 11 now, in an alternative embodiment again, secondary transducers 236 is oriented orthogonal to primary sensor 228.In this embodiment, the sensitive element (not shown) of the sensitive element 242 of secondary transducers 236 even close more primary sensor 228.Can find, by arranging secondary transducers 236, make the not branding surface of secondary transducers 236 be arranged to closely straight the contacting of bottom surface of assembling the L shaped segmentation 218 of pole shoe with the U-shaped flux, the sensitive element 242 of secondary transducers 236 can be with the Hall effect sensitive element of about 0.063 inch spacing near primary sensor 228.In this embodiment, because the detecting element of close more primary and secondary sensor 228,236, more particularly, because secondary transducers 236 is arranged in the passage with higher leakage flux, so, compare with the secondary transducers of Figure 10 embodiment, can obtain bigger output voltage by secondary transducers 238.

Figure 12 is the diagrammatic representation of the exemplary valve throw of lever, use according to this valve rod travel of primary and secondary sensor monitors of one in these the disclosed embodiments, wherein, the voltage output of primary sensor 228 and secondary transducers 236 shows with the DC voltage form, and the stroke or the displacement of the valve rod that the linear movement of the flux source by rectangle carriage (or " magnet carrier ") form is represented show with inch.Shown in the diagrammatic representation, the output of the voltage of secondary transducers 236 is output into direct ratio with the voltage of primary sensor 228 as described.

In addition, people can be arranged in secondary transducers 236 any position of wanting, but preferably are arranged in the high magnetic flux path.That is to say that except the secondary transducers that stands leakage flux or substitute it, secondary transducers can be set in the secondary flux path.Like this, people can utilize structure of magnetic pole to form extra leakage magnetic flux route cause secondary transducers and detect, and perhaps form the magnetic flux path of separating fully that is detected by secondary transducers.Equally, in control circuit, secondary transducers can also be used to other purpose except as the limit switch.

As being schematically shown among Figure 13, primary sensor 228 preferably all is placed as with voltage-level detector 250 with secondary transducers 236 and communicates by letter, and this voltage-level detector detects the voltage that passes primary and secondary sensor 228,236 detecting element 240,242 in each.Voltage-level detector 250 can communicate with processor 252, and processor 252 comprises storer 254, and one or more predetermined voltage of this memory stores can compare the voltage output that records or a plurality of output and predetermined voltage.This processor can also comprise generator output signal 256, this generator output signal according to the output of the 252 pairs of voltages that detected of processor or a plurality of output with storer 254 in one or more selected approaching judgement of predetermined voltage of storage, produce a signal.Then, the controller 258 that receives this signal can correspondingly start one or more suitable control sequence.

Those skilled in the art will recognize that above-mentioned a plurality of embodiment are used for explanation, and are not used in and are defined in the scope of the present disclosure.For example, when the embodiment disclosed herein all is used to detect valve rod travel, can recognize, this explanation can be used to similarly other expectation reliable detection object the position and/or reliably limit the stroke of object and do not need in the situation of a plurality of electro-mechanical limit switches etc.

Claims (17)

1. position sensor assembly comprises:

Primary sensor comprises the Hall effect sensitive element of at least one response magnetic field;

Secondary transducers comprises the Hall effect sensitive element of at least one response magnetic field;

Be used to assemble and the lead U-shaped flux of this primary sensor and this secondary transducers of magnetic flux is assembled pole shoe, it is to form the U-shaped with bifurcated bottom by the first and second L shaped segmentations that the symmetry placement is made by the magnetic penetrable material to constitute that this flux is assembled pole shoe, and the bifurcated bottom of this U-shaped pole shoe has the separately gap of this first and second L shaped segmentation;

Described primary sensor is set between each the end of this first and second L shaped segmentation;

Described secondary transducers is set to stand from described U-shaped pole shoe than this primary sensor the magnetic flux of controlled lower number percent; And

Flux source is used to produce magnetic field,

Wherein the voltage output that produces of the magnetic flux by this primary sensor of guiding of this primary sensor changes with the displacement of this primary sensor with respect to this flux source according to being essentially linear mode.

2. position sensor assembly according to claim 1 also comprises:

From the first asymmetric Y shape part that this first L shaped segmentation is extended, this first asymmetric Y shape partly has a head, and this head comprises first and second ends of extending along this second L shaped segmentation direction;

From the second asymmetric Y shape part that this second L shaped segmentation is extended, this second asymmetric Y shape partly has a head, and this head comprises first and second ends of extending along this first L shaped segmentation direction;

Described primary sensor is arranged between the first end of these first and second asymmetric Y shape parts; And

Described secondary transducers is arranged between the second end of these first and second asymmetric Y shape parts.

3. position sensor assembly according to claim 2 also comprises the adapter between the second end that is arranged in this secondary transducers and the first and second asymmetric Y shape parts.

4. position sensor assembly according to claim 3, wherein this adapter is made of electrically insulating material.

5. position sensor assembly according to claim 4, wherein said electrically insulating material is plastics.

6. according to each described position sensor assembly among the claim 1-5, wherein this secondary transducers is set to be close to this primary sensor, wherein the Hall effect sensitive element of the Hall effect sensitive element of this primary sensor and secondary transducers is by aligned with each other, and is oriented vertical with the end of this L shaped segmentation.

7. position sensor assembly according to claim 6, wherein this secondary transducers is set to vertical with this primary sensor, wherein the Hall effect sensitive element of the Hall effect sensitive element of this secondary transducers and primary sensor is perpendicular, and separately the distance of the Hall effect sensitive element of this primary sensor and secondary transducers is minimized thus.

8. position sensor assembly comprises:

Sensor outer housing;

By the U-shaped pole shoe that this sensor outer housing is aimed at, described U-shaped pole shoe comprises the first L shaped segmentation and the second L shaped segmentation, and wherein this first L shaped segmentation is partly located to stop an asymmetric Y shape, and this second L shaped segmentation is partly located to stop the second asymmetric Y shape;

Primary sensor is disposed between each the first end of this first and second asymmetric Y shapes part, and each first end of the described first and second asymmetric Y shapes parts is positioned at the head of each asymmetric Y shape part; And

Secondary transducers is set between each the second end of this first and second asymmetric Y shapes part, and each the second end of the described first and second asymmetric Y shapes parts is positioned at the head of each asymmetric Y shape part equally.

9. position sensor assembly according to claim 8, wherein this primary sensor comprises at least one sensitive element, described sensitive element is arranged to the first end perpendicular to these first and second asymmetric Y shape parts.

10. position sensor assembly according to claim 9, wherein this secondary transducers comprises at least one sensitive element, described sensitive element is arranged to the second end perpendicular to these first and second asymmetric Y shape parts.

11. each described position sensor assembly according to Claim 8-10 also comprises:

Be arranged in the adapter between the second end of this secondary transducers and one of this first and second L shaped segmentation at least.

12. position sensor assembly according to claim 11, wherein this adapter is made of electrically insulating material.

13. position sensor assembly according to claim 12, wherein said electrically insulating material is plastics.

14. position sensor assembly according to claim 11, wherein this adapter is set between this secondary transducers and first and second asymmetric both the second ends of Y shape part.

15. position sensor assembly according to claim 14, wherein this adapter produces air gap between this secondary transducers and first and second asymmetric both the second ends of Y shape part.

16. position sensor assembly according to claim 15, wherein this air gap is approximately 0.13 inch.

17. position sensor assembly according to claim 8, wherein this secondary transducers is used as limit switch, and described primary sensor is arranged to the magnetic flux that stands bigger number percent than this secondary transducers from described U-shaped pole shoe.

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