Magnetic detection device

Abstract

A magnetic detection device for detecting the presence of a target (602) of a magnetic material, comprising: a sensor housing (116) with side walls (116a-d); a generally U-shaped magnet (308, 702, 902) having an N pole and an S pole, including a pair of spaced legs (310, 704, 914) unitary with a connecting base (311, 712, 906) which together define a first internal channel (314b, 708b, 918b) and a distal plane (318, 718, 912), the base (311) including a pair of steps (402) and a depressed surface (404) between the steps (402) defining a second internal channel (314a) in the magnet (308, 702, 902) which opens into the first internal channel (314b, 708b, 918b); a sensing assembly (316) disposed in the first inner channel (314b, 708b, 918b), including a generally T-shaped circuit board (317) and a sensor (118) extending across the distal plane (318, 718, 912) of the pair of spaced legs (310, 704, 914) of the magnet (308, 702, 902), wherein the generally T-shaped circuit board (317) is spaced and separated from the magnet (308, 702, 902), wherein the circuit board (317) has a central leg portion (317a) and an upper portion (317b), wherein the upper portion (317b) comprises terminals (324), wherein the upper portion (317b) extends between the respective side walls (116a-d) of the sensor housing (116), wherein the central leg portion (317a) extends between the legs (310, 704, 914) of the magnet (308, 702, 902) and is arranged in the first inner channel (314b, 708b, 918b), wherein the sensor (118) is a Hall effect device, wherein the sensor (118) is located on an upper surface of the leg portion (317a) of the circuit board (317), wherein the sensor (118) is spaced and separated from the magnet (308, 702, 902); and wherein the magnet (308, 702, 902) is adapted to create a first region of low or no magnetic flux in the region of the sensor (118) above the distal plane (318, 718, 912) of the magnet (308, 702, 902) and between the pair of spaced legs (310, 704, 914) of the magnet (308, 702, 902) in a first position of the magnet (308, 702, 902) relative to the target (602), to create a second region of low or no magnetic flux in the inner channel (314b, 708b, 918b) of the magnet (308, 702, 902) in a second position of the magnet (308, 702, 902) relative to the target (602), and to create a third region magnetic flux in the region of the sensor (118) above the distal plane (318, 718, 912) of the magnet (308, 702, 902), which previously had the first region of low or no magnetic flux, in the second position of the magnet (308, 702, 902),whereby the sensor (118) is caused to activate a control signal.,

Description

Field of the invention

[0001] The present invention relates to a magnetic sensing device, and more particularly, to a magnetic proximity sensing device for detecting the presence of a target made of a magnetic material. In one embodiment, the invention is practiced in the context of a position sensing system for a motor vehicle seat rail. State of the art

[0002] Modern passenger vehicles typically incorporate advanced safety systems, including active restraints and a variety of airbags and other passive restraint systems. One of the main obstacles for manufacturers and suppliers related to safety standards is ensuring competitive prices while incorporating advanced safety systems. Another issue, particularly related to airbag systems, is the implementation of regulations for deactivating or adapting airbag systems depending on various conditions, including the relative seating position with respect to the dashboard.

[0003] In response to increasingly complex safety regulations, inflatable safety restraint technology has led to the development of what are referred to as "adaptive" or "smart" inflators and associated inflatable restraint systems. Some adaptive systems incorporate multi-stage airbags to adjust deployment based on the relative seat position with respect to the instrument panel. In these systems, the position of each seat is monitored, allowing a vehicle control unit to adjust the stage of each airbag. The disclosed invention relates to a system for monitoring the position of vehicle seats and other related applications.

[0004] A position detection device is known from US 2010 0 026 283 A1. In the position detection device, which includes a movable element slidably mounted on a base member and a proximity sensor that detects the position of the movable element, the proximity sensor includes a magnetic field generating portion, a detecting portion that detects a change in the magnetic field corresponding to the displacement of the movable element, and a protruding portion made of a non-magnetic material that protrudes toward an object to be detected.

[0005] Further prior art is known from US 2003 0 155 909 A1, US 4 618 823 A, and US 7 112 955 B2. Brief description of the invention

[0006] The present invention is directed to a magnetic sensing device for sensing the presence of a target of a magnetic material, comprising a sensor housing with side walls, a generally U-shaped magnet having an N-pole and an S-pole, including a pair of spaced legs unitary with a connecting base that together define a first internal channel and a distal plane, the base including a pair of steps and a depressed surface between the steps that defines a second internal channel in the magnet that opens into the first internal channel, a sensing assembly disposed in the first internal channel, including a generally T-shaped circuit board and a sensor extending across the distal plane of the pair of spaced legs of the magnet, the generally T-shaped circuit board being spaced and separate from the magnet,wherein the circuit board has a central leg portion and an upper portion, the upper portion comprising terminals, the upper portion extending between the respective side walls of the sensor housing, the central leg portion extending between the legs of the magnet and being disposed in the first internal channel, the sensor being a Hall effect device, the sensor being located on an upper surface of the leg portion of the circuit board, the sensor being spaced apart and separate from the magnet, and the magnet being arranged to produce a first region of low or no magnetic flux in the region of the sensor above the distal plane of the magnet and between the pair of spaced apart legs of the magnet in a first position of the magnet with respect to the target,a second region of low or no magnetic flux in the inner channel of the magnet in a second position of the magnet relative to the target and a third region of magnetic flux in the region of the sensor above the distal plane of the magnet, which formerly had the first region of low or no magnetic flux, in the second position of the magnet, which causes the sensor to activate a control signal.

[0007] In one embodiment, the base of the magnet includes a pair of steps and a depressed surface between the steps defining a second internal channel in the magnet that opens into the first internal channel.

[0008] In one embodiment, the recessed surface in the base of the magnet is generally rectangular in shape and defines a generally rectangular-shaped second interior channel in the magnet.

[0009] In one embodiment, the depressed surface in the base of the magnet is generally concave in shape and defines a generally concave-shaped second interior channel in the magnet.

[0010] In one embodiment, the depressed surface in the base of the magnet is generally V-shaped and defines a generally V-shaped second, internal channel in the magnet.

[0011] Further areas of applicability will become apparent from the description provided herein. Detailed description of the drawings Fig. 1 is a pictorial perspective view of a seat track system in an extended position according to the present invention; Fig. 2 is a pictorial perspective view of a seat track system in a retracted position according to the present invention; Fig. 3 is a pictorial perspective view of a sensor housing or assembly according to the present invention; Fig. Figure 4 is a vertical cross-sectional view of the U-shaped magnet and sensor assembly according to the present invention; Fig. 5 is a profile elevational side view of the U-shaped magnet illustrating a characteristic magnetic field according to the present invention; Fig. 6 is a profile elevational side view of the U-shaped magnet adjacent to a ferromagnetic component illustrating a characteristic magnetic field according to the present invention; Fig. 7 is a pictorial perspective view of another exemplary U-shaped magnet according to the present invention; Fig. 8 is a profile elevational side view of the U-shaped magnet of Fig. 7, which illustrates a characteristic magnetic field according to the present invention; Fig. 9 is a pictorial perspective view of another exemplary U-shaped magnet according to the present invention; and Fig. 10 is a profile elevational side view of the U-shaped magnet of Fig. 9, which illustrates a characteristic magnetic field according to the present invention. Detailed description of the examples

[0012] The magnetic sensing device or proximity sensing device described herein can be used in a variety of applications related to sensing changes in magnetic fields. One embodiment of the magnetic sensing device relates to sensing the position of a seat configured to slide and adjust along rails, which is typically implemented in front seats of passenger vehicles.

[0013] With reference to Fig. 1 illustrates a magnetic sensing device assembly 102 integrated into a seat track system 104 according to the teachings of the disclosed invention. The seat track system 104 includes a fixed track or magnetic target 106 and a slide track 108, which Fig. 1 are shown in an extended position.

[0014] The rail 106, in this implementation, is attached to a floor of a passenger conveyor vehicle and includes an outer profile 110. The slide rail 108 is disposed within the outer profile 110 of the rail 106 and slidably engages the rail 106, allowing a seat to be positioned in a fore / aft (extended / retracted position) direction relative to the vehicle. A mounting bracket 112 may be attached to a distal end portion 114 of the slide rail 108 for attachment of a seat assembly or an intermediate mounting bracket. The seat may be positioned along the fore / aft longitudinal axis by a lever configured to engage a series of retention apertures to maintain the seat in a desired position (not shown). Another implementation of the disclosure may provide an adjustment system for a power seat.The design and operation of the seat adjustment system are well known in the art and are only outlined here.

[0015] This implementation may further include the magnetic sensing device assembly 102, which includes a sensor housing or assembly 116 attached to the mounting bracket 112 and, in the example shown, is configured to extend outwardly from an outer side of the mounting bracket 112. The sensor housing 116 may be mounted such that, when the seat is returned to the rearward or forward position, a sensor device 118 disposed within the sensor housing 116 ( Fig. 3 and Fig. 4) is arranged adjacent to the outer profile 110 of the rail 106 and superimposed thereon.

[0016] With reference now to Fig. 2, the seat track system 104 is illustrated as having the slide rail 108 in a retracted position according to one implementation of the present invention. Fig. Figure 2 more clearly illustrates a lower surface or wall or plate 202 of the magnetic sensing device assembly 102 configured to substantially align in a spaced and generally parallel and overlying relationship with an upper surface or wall 204 of the rail 106. When the slide rail 108 is positioned or retracted so that the sensor device 118 is aligned within the sensor housing 116 over the rail or target 106, the sensor device 118 detects the presence of the ferromagnetic material of the rail 106. The term ferromagnetic, as used herein, refers to materials that are strongly attracted to magnets, including iron, nickel, cobalt, alloys thereof, etc.Once the sensor device 118 detects the presence of the rail 106, a control signal may be activated to inform a vehicle control unit of the position of the seat relative to a vehicle dashboard.

[0017] With reference to Fig. 3 illustrates a pictorial perspective view of the sensor housing or assembly 116 of the assembly 102 according to the teachings of the present invention. The sensor housing 116 includes and defines an internal insert mold cavity 302, a plurality of hollow and generally cylindrically shaped sensor housing cover receiving flanges 304 formed within the cavity 302, and a hollow and generally cylindrically shaped mounting flange 306 projecting outwardly from the outer surface of one of the vertical side walls 116b of the housing 116 for mounting the magnetic sensing device assembly 102 to the mounting bracket 112. The insert mold cavity 302 is configured to receive a generally U-shaped magnet 308 ( Fig. 4) including two legs 310 having inner side walls 312 defining an inner channel or channel section 314.

[0018] As in Fig. 4, the U-shaped magnet 308 further includes two spaced, parallel, vertical legs 310 integral with a lower horizontal connecting base 311. Each of the legs 310 includes an inner, vertical sidewall 312, and the base 311 includes an inner, upper, depressed base wall 404. The sidewalls 312 and the base wall 404 together define the inner, open channel or channel portion 314 of the magnet 308, which includes a lower, inner, generally rectangular-shaped, depressed base channel or channel portion 314a that opens into a wider, inner, open, central, rectangular-shaped, open channel or channel portion 314b.

[0019] Each of the legs 310 of the magnet 308 includes a distal horizontal end surface or face 320, which together define the distal horizontal plane 318 of the magnet 308.

[0020] In the example shown, the base channel portion 314a is defined by the groove or recess formed in the base 311 by the depressed base wall 404, which extends downward into the material of the base 311 of the magnet 308. In the example shown, the width and area of ​​the depressed base channel portion 314a and the depressed base wall 404 is less than the width and area of ​​the upper channel portion 314a and less than the distance between the opposite and facing inner sidewalls 312 of the legs 310 of the magnet 308 to define a horizontal base shoulder or step portion, or a step or surface 402, between the respective sidewalls 312 of the legs 310 and the base channel portion 314a. Therefore, in the example shown, the recessed base wall 404 and the recessed channel 314a are located between two steps 402 in the base 311.

[0021] During assembly of the magnetic sensing device assembly 102, the U-shaped magnet 308 is disposed within the sensor housing 116 and held therein by resin material. As shown in Fig. 3, the housing 116 is generally square in shape and includes a first pair of opposed first sidewalls 116a and 116b and a second pair of opposed vertical sidewalls 116c and 116d normal to and extending between the sidewalls 116a and 116b. The magnet 308 is disposed within the housing 116 in a vertical relationship with the outwardly facing sidewall 315 of the respective legs 310 opposite and parallel to the inner surface of the respective housing sidewalls 116a and 116b.

[0022] As described in more detail below, the U-shaped magnet 308 disclosed in the present invention is constructed such that a region of low or no magnetic flux, i.e., a region of flux having a minimal or zero magnitude / strength that is not sensed by the sensor device 118 and is insufficient to cause the sensing component of the sensor device 118 to activate a control signal, is present beyond or above the horizontal plane 318 defined by a distal, horizontal, and outer surface or side 320 of the legs 310 of the magnet 308 and beyond and above the channel 314 of the magnet 308 in the positions of the magnet 308 and the slide rail 108 in Fig. 1 and Fig. 5. The materials used to produce permanent magnets are well known in the art and may include alnico, ferrite, etc.

[0023] The configuration of the U-shaped magnet 308, which creates the region of low or no magnetic flux beyond and above the distal horizontal plane 318 of the magnet 308, is essential to ensure that the sensor device 118 accurately identifies the ferromagnetic material in the magnetic field of the U-shaped magnet 308.

[0024] The following detailed description discloses exemplary implementations of the U-shaped magnet 308 according to the invention.

[0025] As in Fig. 3 and Fig. 4, the sensor assembly 316 includes the sensor device 118 capable of detecting changes in the magnetic magnitude / strength and / or direction of a localized magnetic field or flux (e.g., Hall effect sensors, magnetic diodes, magnetic transistors, magnetometers, etc.), and preferably includes an HED. The sensor assembly 316 further includes a pair of terminals 324 and control circuits in the form of capacitors, inductors, etc. (which are shown in Fig. 3 are generally designated by reference numeral 325) to ensure proper operation of the sensor device 118. The sensor device 118 is disposed on top of the outer surface of a substrate or printed circuit board 317 of the sensor assembly 316 to position a sensing component of the sensor device 118 centrally located to the region of low or no magnetic flux beyond the distal plane 318.

[0026] In the example shown, the sensor assembly 316 further includes, in particular, a generally T-shaped plate or substrate or integrated printed circuit board 317 disposed and mounted within the cavity 302 of the housing 116 in a relationship wherein a centrally located post or leg portion 317a of the T-shaped plate 317 is disposed within and extends through the upper portion 314b of the channel 314 of the magnet 308, and an upper portion 317b of the T-shaped plate 317 is disposed between and extends between the respective side walls 116a and 116b of the sensor housing 116. The sensor device 118 and capacitors, inductors, etc., generally designated by the reference numeral 325, are located on the upper surface of the leg portion 317a of the plate 317 and positioned such that a lower portion of the sensor 118 is located within the open channel 314 of the magnet 308, and an upper portion of the sensor 118 and the sensing component (not shown) thereof extend from the channel 314 and are located in the region above and beyond the distal end surface 320 of the legs 310 of the magnet 308 and the distal horizontal plane 318 of the magnet 308. The terminals 324 extend through the upper portion 314b of the plate 317.

[0027] With reference to Fig. 4 illustrates a vertical cross-sectional view of the U-shaped magnet 308 and sensor assembly 316 according to the teachings of the present invention. The U-shaped magnet 308 shown has a shape consistent with the front-to-back profile illustrated. The north pole N and south pole S of the U-shaped magnet 308 are aligned perpendicularly to the distal horizontal plane 318, the horizontal base wall 311 of the magnet 308, and the horizontal plate 317 of the sensor assembly 316. Fig. 4 illustrates the north pole N adjacent to the upper distal horizontal surface 320 of each of the legs 310 of the magnet 308 and the south pole adjacent to the lower wall adjacent to the horizontal base wall 311 of the magnet 308. The polarity in this and all other presently disclosed implementations may be reversed from the direction shown in the FIGS. and still remain within the scope of the invention.

[0028] Fig. 4 and Fig. 5 further show the sensor device 118 against the outer surface 326 of the plate 317 of the sensor assembly 316 and projecting from and above the channel portion(s) 314 of the magnet 308. The sensing component (not shown) of the sensor device 118 is located in the upper portion of the sensor device 118 and is beyond and above the distal horizontal plane 318 of the magnet 308 and beyond and above the distal horizontal plane 320 of the respective legs 310 of the magnet 308 and within the region of low or no magnetic flux passing through the magnet 308 in the positions of the slide rail 108 and the magnet 308 in Fig. 1 and Fig. 5 is generated. The configuration of the sensing component of sensor 118 in this implementation provides for sensor 118 to accurately detect changes in the magnitude / strength and / or direction of the magnetic field or flux of U-shaped magnet 308 by positioning the sensing component in the low or no flux region outside and above both channel sections 314 and the distal horizontal plane 318.

[0029] With reference to Fig. 5 illustrates a profile view of the U-shaped magnet 308 illustrating a characteristic magnetic field 502 in accordance with the teachings of the present invention. The magnetic field is characterized by flux lines, illustrated herein by a plurality of arrows 504. The arrows 504 indicate the direction of flux flowing from the north pole to the south pole S. North pole regions P are further identified by the regions where the flux arrows exit the U-shaped magnet 308. In this implementation, a region of low or no magnetic flux 506 is created by the aforementioned physical properties of the U-shaped magnet 308 and is illustrated as the region having no or minimal arrows and further highlighted by a rectangular phantom box labeled 506a in the illustration.

[0030] The combination of the U-shaped configuration of the magnet 308 with vertically spaced legs 310, horizontal base 311, internal channel 314 between the legs 310, recessed channel 314a defined in the base 311 and horizontal steps 402 between the channel 314a and the legs 310 create a region of low or no flux 506a beyond and above the distal horizontal plane 318, the distal horizontal side 320 of the respective legs 310 of the magnet 308 and the channel 314 in the position of the slide rail 108 in Fig. 1 relative to the fixed rail 106. In some implementations of the magnet 308, the low or no flux region 506 may be located at least 0.1 mm outside the channel gate 314 relative to the distal plane 318 and the distal side 320 of the legs 310 of the magnet 308.

[0031] Therefore, a distinct advantage of the presently disclosed configurations as described above is the creation of a low or no flux region 506a defining a sensing component location beyond and above the distal horizontal plane 318 defined by the horizontal distal end surface 320 of the legs 310 of the U-shaped magnet 308. The various implementations disclosed herein enable the use of smaller magnets, which may translate into cost savings and reduced size ratios of the magnetic sensing device assembly 102 and the sensor housing 116.

[0032] With reference to Fig. 6, a profile view of the U-shaped magnet 308 adjacent a ferromagnetic component or target 602 (such as the seat rail 106) illustrating a characteristic magnetic field 604 is illustrated in accordance with the teachings of the present invention. A displaced or fixed region of no or low magnetic flux 506b, generally indicated by a first rectangular phantom box, is created and located in the channel portion 314 of the magnet 308 due to the introduction of the ferromagnetic component 602 into the magnetic field 604, and a region of flux 608, also generally indicated by a rectangular phantom box and defining a location or area of ​​a sensing component, illustrates that the sensing component (not shown) located in the upper portion of the sensor 118 is now exposed to the magnetic field 604.As illustrated by the arrows traversing the location of the sensing component, flux flows through the sensor 118 and the sensing component thereof in a generally up-and-down and vertical relationship and direction generally normal to the longitudinal or horizontal axis of the sensor 118 when the ferromagnetic component 602 is present. The flux flowing through the sensing component, and more particularly, the magnitude and / or direction of the magnetic flux in the region of flux 608, has a sufficient predetermined minimum value that causes the sensor device 118 to activate a control signal to notify the vehicle control unit of the presence of a ferromagnetic material.In the presently disclosed seat track system 104 implementation, the presence of the control signal may inform the vehicle control unit that the seat is in a position as shown in FIG. Fig. 2 shown reset position.

[0033] Therefore, Fig. 5, as described above, the magnetic flux generated by the magnet 308 with the slide rail 108 in its extended position (forward position of the vehicle seat) relative to the fixed rail 106, as in Fig. 1 shown. Fig. Figure 6 shows the magnetic flux generated by the magnet 308 with the slide rail 108 in its retracted position (rear / back position of the vehicle seat) relative to the fixed rail 106, as in Fig. 2, in which the magnetic detection device 102 overlies the fixed rail 106.

[0034] As described above, the movement of the slide rail 108 from its position in Fig. 1 to their position in Fig. 2, that the area of ​​low or no magnetic flux from its first, generally indicated by box 536a in Fig. 5, in which the region of low or no magnetic flux is located in the region above the horizontal, distal plane 318 of the magnet 308 and the channel 314 of the magnet 308, to the second, generally indicated by the box 506b in Fig. 6, in which the region of low or no magnetic flux is located below the horizontal plane 318 of the distal magnet 308 and in the section 314b of the channel 314 of the magnet 308. The movement of the slide rail 108 between its positions in Fig. 1 and Fig. 2 also creates a region of magnetic flux 608 in the area above the distal horizontal plane 318 formerly occupied by the region of no flux 506a, the magnitude and / or direction of which is detected and sensed by the sensing component of the sensor 118 and causes the activation of a signal that identifies the position of the vehicle seat.

[0035] The movement of the slide rail from its position in Fig. 1 in their position in Fig. 2 thus causes the former area of ​​low or no flow 506a in Fig. 5 to river area 608 of Fig. 6 and that the low or no flow region 506a moves down into the channel 314 and becomes the low or no flow region 506b.

[0036] Fig. 7-10 illustrate two further exemplary magnets 702 and 902 which differ from magnet 308 in shape and configuration but are adapted to generate magnetic flux regions and fields of similar orientation and function to the magnetic flux fields generated by magnet 308, and thus the previous description of the magnetic flux regions and fields with reference to Fig. 5 and Fig. 6 is incorporated herein by reference with respect to the exemplary magnets 702 and 902.

[0037] With reference to Fig. 7 illustrates a perspective view of another implementation of a U-shaped magnet 702 according to the teachings of the presently disclosed invention. Similar to the Fig. 3, this implementation includes a U-shaped magnet 702 having two legs 704 that include inner sidewalls 706 and an inner channel or channel portion 708. The U-shaped magnet 702 can also be configured in the same manner as in Fig. 1 and incorporated into the magnetic sensing device assembly 102, and thus, the previous description is incorporated herein by reference with respect to the magnet 702. The U-shaped magnet 702 further includes steps or stepped portions 710 disposed within the channel portion 708 and extending along a base portion or section 712 and abutting each leg 704. A base ramp portion 714 extends between the stepped portions 710.

[0038] The U-shaped magnet 702 further includes in particular and as shown in Fig. 7, a pair of spaced-apart, parallel, vertical legs 704 are shown unitary with a lower horizontal connecting base 712. Each of the legs 704 includes an inner vertical sidewall 706, and the base 712 includes an inner, upper, depressed base wall or ramp portion 714. The sidewalls 706 and the depressed base wall or ramp portion 714 together define the inner open channel portion 708 of the magnet 702, which includes a lower, inner, generally semicircular or concave depressed base channel or channel portion 708a that opens into a wider and larger inner, open, generally rectangular channel or channel portion 708b.

[0039] In the example of Fig. 7, the recessed concave base channel 708a is defined by the generally semicircular or concave-shaped recessed ramp portion or wall 714 of the base 712, which defines a generally concave and semicircular-shaped groove or recess in the base 712 of the magnet 702. In the example shown, the width of the ramp portion or wall 708 and the area of ​​the channel 708a is less than the distance between the inner vertical sidewalls 706 of the legs 704 of the magnet 702 and the area of ​​the channel 708b to define the horizontal base shoulder or step portion, or the step or surface 710 between each of the respective sidewalls 706 of the legs 704 and the base channel portion 708a defined by the base ramp portion 714. In this example, the recessed base wall 714 and the recessed base channel 708a are therefore located between the two steps 710 in the base 712.

[0040] In the example of Fig. 7, the depressed base ramp section or wall 714 defines a profile with a gradually increasing slope extending from the base section 712 to the stepped section 710. This implementation also provides a region of low or no magnetic flux defining a location of a sensing component and formed beyond a distal horizontal plane 718 defined by a distal horizontal face or side 720 of the legs 704 of the magnet 702. The north pole N and south pole S of the U-shaped magnet 702 are aligned and extend in a direction perpendicular to the distal horizontal plane 718 and in the same direction as the vertical legs 704 of the magnet 702.

[0041] With reference to Fig. 8 illustrates a profile view of the U-shaped magnet 702, illustrating a characteristic magnetic field 802, in accordance with the teachings of the present invention. The magnetic field 802 is characterized by flux lines, illustrated herein by a plurality of arrows 804. The arrows 804 indicate the direction of the flux flowing from the north pole N to the south pole S.In this implementation, a region of low or no magnetic flux 806 is created by the physical characteristics of the U-shaped magnet 702, and more particularly, the combination of a U-shaped magnet 702 with vertical legs 704, horizontal base 712, internal channel 708 between the legs 704, concave channel portion or recess 708a defined in the base 712, and steps 710 between the channel portion 708a and the legs 704, and is illustrated as the region having no or minimal arrows and further highlighted by a phantom rectangular box labeled 806 in the illustration. In the same manner as previously described and illustrated in FIG. Fig. 5, the low or no flux region 806 defines a location of a sensing component beyond and above the distal horizontal plane 718 and the distal horizontal end faces 720 of the legs 704 of the magnet 702, allowing the use of smaller magnets, which may translate into cost savings and reduced size ratios of the magnetic sensing device assembly 102 and the sensor housing 116.

[0042] Therefore, and although not described in detail here, it is understood that Fig. 8 which is held by the magnet 702 in the position of Fig. 1 generated magnetic field of the slide rail 108 and that the movement of the slide rail 108 from its position in Fig. 1 in their position in Fig. 2 leads to the generation of a magnetic field by the magnet 702, which corresponds to the Fig. 6, resulting in the movement of the low or no flux region 806 from the position in Fig. 8 to the generally indicated by box 506b in Fig. 6 and to the creation of an area of ​​flow 608 in the area 806 previously occupied by the area of ​​low or no flow in Fig. 8, which allows the sensing component of the sensor 118 to generate a control signal.

[0043] With reference to Fig. 9 illustrates a perspective view of another implementation of a U-shaped magnet 902 according to the teachings of the disclosed invention. This implementation of the U-shaped magnet 902 is substantially similar to the Fig. 4 and Fig. 7 and has the same features and properties, the description of such features and properties being incorporated herein by reference. The relevant differences to the implementation of Fig. 7 included in this implementation include a ramp portion 904 extending from the base portion 906 to a step portion 908. The ramp portion 904 in this implementation differs in that the gradient of the ramp 904 extends substantially continuously from the base portion 906 to the upper step 908, forming a triangular profile. Similar to other implementations, this implementation also provides a region of low or no magnetic flux defining a sensing component location that forms beyond a distal plane 912 of the magnet and a distal horizontal end face 920 of the legs 314 of the magnet 902.

[0044] The U-shaped magnet 902 includes, as further described in more detail in Fig. 9, two spaced-apart, parallel, vertical legs 914 that are unitary with a lower, horizontal connecting base 908. Each of the legs 906 includes an inner, vertical sidewall 916, and the base 906 includes an inner, upper, depressed base wall or ramp portion 904. The sidewalls 916 and the base wall or ramp portion 904 together define the inner, open channel portion 918 of the magnet 902, which includes a lower, inner, generally triangular-shaped, depressed base channel or channel portion 918a that opens into a wider and larger, inner, open, centrally located, generally rectangular-shaped channel or channel portion 918b.

[0045] In the example of Fig. 9, the countersunk base channel or channel portion 918a is defined by the generally triangular-shaped countersunk ramp portion or wall 904 of the base 906, which defines a generally triangular-shaped countersunk groove or recess extending into the material of the base 906 of the magnet 902. In the example shown, the width of the countersunk ramp portion or wall 904 and the area of ​​the channel 918a is less than the distance between the inner vertical sidewalls 916 or legs 914 of the magnet 902 and the area of ​​the channel 918b and defines the horizontal base shoulder or step portion or step or surface 908 between the respective sidewalls 916 of the legs 904 and the base channel portion 918a defined by the base ramp portion 904. In the example shown, the recessed base wall 904 and the recessed channel 918a are therefore arranged between the two steps 908 in the base 906.

[0046] With reference to Fig. 10 illustrates a profile view of U-shaped magnet 902 illustrating a characteristic magnetic field 1002 in accordance with the teachings of the present invention. In this implementation, a region of low or no magnetic flux 1004 is created by the physical characteristics of U-shaped magnet 902, and more particularly, the combination of a U-shaped magnet 902 with vertical legs 914, horizontal base 906, internal open channels 918a and 918b, and steps 908, and is illustrated as the region having minimal or no arrows and further highlighted by a rectangular box labeled 1004 in the illustration.In this implementation, as well as in the various other implementations disclosed herein, the description of which is incorporated herein by reference, the sensing component of the magnetic sensing device is located in a low or no flux region outside the channel portion 918 and the horizontal plane 912 of the magnet 902 in the position shown in FIG. Fig. 1 of the magnetic detection device 102.

[0047] Therefore, and although not described in detail here, it is understood that Fig. 10 which is held by the magnet 902 in the position of Fig. 1 generated magnetic field of the slide rail 108 and that the movement of the slide rail 108 from its position in Fig. 1 in their position in Fig. 2 results in the generation of a magnetic field by the magnet 902, which corresponds to the Fig. 6, resulting in the movement of the low or no flux region from the position in Fig. 10 to the generally indicated by box 506b in Fig. 6 and to the creation of an area of ​​flow 608 in the area 806 previously occupied by the area of ​​low or no flow in Fig. 10, which allows the sensing component of the sensor 118 to generate a control signal.

Claims

Magnetic detection device for detecting the presence of a target (602) of a magnetic material, comprising:a sensor housing (116) with side walls (116a - d);a generally U-shaped magnet (308, 702, 902) with an N-pole and an S-pole, including a pair of spaced legs (310, 704, 914) that are integrally connected to a connecting base (311, 712, 906) which together define a first inner channel (314b, 708b, 918b) and a distal plane (318, 718, 912), wherein the base (311) includes a pair of steps (402) and a recessed surface (404) between the steps (402) that defines a second inner channel (314a) in the magnet (308, 702, 902) that opens into the first inner channel (314b, 708b, 918b);a detection arrangement (316) disposed in the first inner channel (314b, 708b, 918b), including a generally T-shaped circuit board (317) and one that extends over the distal plane (318, 718,912) of the pair of spaced-apart legs (310, 704, 914) of the magnet (308, 702, 902) extending sensor (118), wherein the generally T-shaped circuit board (317) is spaced and separate from the magnet (308, 702, 902), wherein the circuit board (317) has a central leg portion (317a) and an upper portion (317b), wherein the upper portion (317b) includes terminals (324), wherein the upper portion (317b) extends between the respective side walls (116a-d) of the sensor housing (116), wherein the central leg portion (317a) extends between the legs (310, 704, 914) of the magnet (308, 702, 902) and disposed in the first inner channel (314b, 708b, 918b), wherein the sensor (118) is a Hall effect device, wherein the sensor (118) is located on an upper surface of the leg portion (317a) of the circuit board (317), wherein the sensor (118) is spaced and separated from the magnet (308, 702, 902); and wherein the magnet (308, 702,902) is adapted to create a first region of low or no magnetic flux in the region of the sensor (118) above the distal plane (318, 718, 912) of the magnet (308, 702, 902) and between the pair of spaced legs (310, 704, 914) of the magnet (308, 702, 902) in a first position of the magnet (308, 702, 902) relative to the target (602), to create a second region of low or no magnetic flux in the inner channel (314b, 708b, 918b) of the magnet (308, 702, 902) in a second position of the magnet (308, 702, 902) relative to the target (602), and to create a third region of magnetic flux in the region of the sensor (118) above the distal plane (318, 718, 912) of the magnet (308, 702, 902), which previously had the first region of low or no magnetic flux, in the second position of the magnet (308, 702, 902), thereby causing the sensor (118) to activate a control signal., The magnetic sensing device of claim 1, wherein the recessed surface (404) is generally rectangular in shape and defines a generally rectangular-shaped second internal channel (314) in the magnet (308). The magnetic sensing device of claim 1, wherein the recessed surface (714) is generally concave in shape and defines a generally concave-shaped second internal channel (708a) in the magnet (702). The magnetic sensing device of claim 1, wherein the recessed surface (904) is generally V-shaped and defines a generally V-shaped second internal channel (918a) in the magnet (902).

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