JP5142381B2 - Non-contact level sensor - Google Patents

Description

  The present invention relates to a non-contact type liquid level sensor, and more particularly to a non-contact type liquid level sensor that can simplify the assembly method and reduce costs.

  An example (for example, patent document 1) of the conventional non-contact-type liquid level sensor will be described. FIG. 8 is a longitudinal sectional view of a conventional non-contact type liquid level sensor, FIG. 9 is a perspective view showing a positional relationship among a magnetoelectric conversion element, a magnet, and a stator extracted from the non-contact type liquid level sensor of FIG. 10 is an enlarged longitudinal sectional view of a main part showing a state in which a magnet chamber cover is mounted in the magnet chamber in a conventional non-contact type liquid level sensor.

  As shown in FIG. 8, the conventional non-contact type liquid level sensor 100 is disposed so that a sensor housing 110 made of synthetic resin is fixed in a vehicle fuel tank 190. A rotating shaft 120 is rotatably disposed in a magnet chamber 110A formed in the sensor housing 110, and a sintered magnet 130 is fitted to the outer peripheral surface of the rotating shaft 120, and the sintered magnet 130 is bonded or engaged. It is being fixed to the rotating shaft 120 by such means.

  The sintered magnet 130 is, for example, a ferrite magnet or the like that is magnetized in an annular shape and baked, and then magnetized in the radial direction. The sintered magnet 130 is hard and brittle, and cracks and the like are generated when insert molding described later is performed. Therefore, after the main body portion is formed by insert molding, the rotating shaft is bonded by means such as adhesion or engagement as described above. 120 is fixed.

  As shown in FIG. 10, a synthetic resin magnet chamber cover 111 is formed in the opening of the magnet chamber 110 </ b> A, with claws 110 </ b> B formed in the sensor housing 110, and locking holes 111 </ b> A provided in the magnet chamber cover 111. Are fixed by engaging them. Furthermore, a support hole 111B is formed in the magnet chamber cover 111, and one end of the rotating shaft 120 is inserted into the support hole 111B and supported rotatably.

  As shown in FIG. 8, the other end of the float arm 150 having one end attached to the float 140 is fitted into the hole of the rotating shaft 120 and is fixed to the rotating shaft 120 integrally. When the float 140 moves up and down with the level displacement of the liquid level L, the up and down movement is transmitted to the rotary shaft 120 via the float arm 150 and rotates the rotary shaft 120.

  As shown in FIG. 9, the stator 160 is configured by combining a pair of substantially semicircular ones, facing the outer peripheral surface of the sintered magnet 130, and facing each other so as to form a substantially circle. ing. Two gaps G having a phase difference of 180 ° are formed between both end faces of the pair of stators 160. One gap G has a magnetoelectric conversion element 170 such as a Hall element or a Hall IC. Are arranged so as to be sandwiched between a pair of stators 160. A terminal 170 </ b> A of the magnetoelectric conversion element 170 is electrically connected to the wiring board 180 shown in FIG. 8, and a terminal 180 </ b> A is electrically connected to the wiring board 180.

  When the float 140 moves up and down with the level displacement of the liquid level L, the rotating shaft 120 rotates together with the sintered magnet 130. When the magnetic flux density passing through the magnetoelectric conversion element 170 changes with the rotation of the sintered magnet 130, the magnetoelectric conversion element 170 detects this, converts it into an electrical signal, and outputs it to the terminal 180A.

Next, a manufacturing method of this type of non-contact type liquid level sensor will be described.
(A) For example, as shown in FIG. 11, an electronic component 210 such as a Hall IC, a resistor, or a capacitor is first welded to the lead frame 220 to form a lead frame assembly 200.
(B) Next, as shown in FIG. 12, in the cavity C of the molds 300A and 300B, the lead frame assembly 200 is set as a core that is held by the movable pins 310A and 310B, and the resin material for molding is set in the cavity. C is injected into the interior, and the movable pins 310A and 310B are removed and insert molding is performed. In FIG. L. Indicates a parting line. As a result, the frame 400 shown in FIG. 13 in which the lead frame assembly is integrally formed is formed.
(C) Further, as shown in FIG. 14A, the magnet 510 is formed by integrally bonding the magnet 510 and the magnet holder 520.
(D) Finally, as shown in FIG. 14B, the magnet assembly 500 is mounted in the magnet chamber 410 on the side surface of the frame 400 and the arm 600 is inserted into the hole 520A at the center of the magnet holder 520 of the magnet assembly 500. The tip 600A is pressed.
JP 2004-37196 A

However, the conventional non-contact type liquid level sensor manufacturing method has the following disadvantages.
(I) Since insert molding is performed using a lead frame assembly, a molding operator is required. In addition, since a thin lead frame that is fragile in shape is inserted, a molding die containing a movable pin is required to prevent deformation.
(Ii) In order to prevent the magnet assembly from coming off the holder, the arm is press-fitted, and a press-fitting press machine is required at that time.
(Iii) Since the magnet assembly is bonded and fixed to the holder, an adhesive applicator is required.

  The present invention has been made in view of the above-described circumstances, and its purpose is to eliminate the insert molding and press-fitting processes, and to reduce the cost by simplifying the assembly method. It is to provide a level sensor.

In order to achieve the above-described object, a non-contact type liquid level sensor according to the present invention is characterized by the following (1).
(1) a lead frame with electronic components attached;
A magnet holder that houses the magnet inside;
A frame having a lead chamber in which the lead frame is mounted, an opening opened on one side surface of the lead chamber, and a central shaft that rotatably supports the magnet holder;
An arm having one end fixed to the magnet holder and having the other end attached to a float that moves up and down according to the level of the liquid level;
A cover attached to the lead frame so as to accommodate the frame in which the lead frame is attached to the lead chamber and the magnet holder to which the arm is fixed is rotatably supported;
With
The opening is provided on one side of the frame, and the central axis is provided on the other side of the frame located opposite to the one side;
The magnet holder has an insertion hole that is drilled in a direction from the magnet holder toward the frame when the magnet holder is rotatably mounted on the central axis, and through which one end of the arm is inserted,
The arm is fixed to the magnet holder so that one end portion of the arm passes through the insertion hole, and has a bent portion at at least one position from one end portion to the other end portion of the arm,
One wall surface of the cover attached to the frame so as to accommodate the frame therein forms one side surface of the lead chamber by facing the opening, and a wall surface opposite to the one wall surface is The one end portion of the arm is held in a state of being inserted through the insertion hole by facing the furthest portion of the arm accommodated by the cover that is farthest from the magnet holder.

  According to the non-contact type liquid level sensor having the configuration (1), since the lead frame is fixed to the lead chamber of the frame by the cover, it is not necessary to insert-mold the lead frame during manufacture. It becomes. Thereby, the metal mold | die containing a movable pin becomes unnecessary and can aim at the cost reduction of a metal mold | die. In addition, since the cover covers the frame with the arm mounted with the magnet holder inserted through the insertion hole, one side wall of the cover is sealed by one wall surface of the lead chamber, and the arm comes out of the magnet holder. Another wall can prevent that. For this reason, in manufacturing, it is only necessary to insert one end of the arm into the insertion hole without press-fitting the arm into the magnet holder, and a press machine for press-fitting is not required, thereby reducing the cost.

In order to achieve the above-described object, the non-contact type liquid level sensor according to the present invention is characterized by the following (2).
(2) In the non-contact liquid level sensor having the configuration of (1) above,
The magnet holder has a holding groove provided on the outer peripheral surface of the magnet holder and extending in a direction perpendicular to the direction of the insertion hole formed in the magnet holder;
The arm is fixed to the magnet holder so that one end portion of the arm passes through the insertion hole, and a part of the arm perpendicular to the one end portion of the arm is narrowed by the holding groove by the bent portion. Held,
The wall surface opposite to the one wall surface faces a part of the arm held by the holding groove, thereby maintaining a state where one end of the arm is inserted through the insertion hole.
about.

  According to the non-contact type liquid level sensor having the configuration (2), since the cover is mounted on the frame so as to face the outer peripheral surface of the magnet holder, the cover can be reduced in size. Further, since the rotation of the arm around the one end portion of the arm is effectively transmitted to the magnet holder by the holding groove, it is not necessary to firmly fix the one end portion of the arm to the insertion hole. It is sufficient to insert the into the insertion hole. For this reason, the man-hour required in order to manufacture a non-contact-type liquid level sensor can be reduced.

In order to achieve the above-described object, the non-contact liquid level sensor according to the present invention is characterized by the following (3).
(3) In the non-contact type liquid level sensor configured as described in (1) or (2) above,
The frame has a locking projection for fixing the cover attached from above in the longitudinal direction of the frame on the outer peripheral surface of the frame,
The cover has a locking claw locked to the locking projection at a position facing the locking projection when the cover is mounted from above in the longitudinal direction of the frame on the inner peripheral surface of the cover. ,
about.

  According to the non-contact type liquid level sensor having the configuration (3), it is not necessary to adhere and fix the cover to the frame, and no dispenser for adhesive or a thermostat for curing is required, thereby further reducing costs.

  According to the non-contact type liquid level sensor of the present invention, since the lead frame is fixed to the lead chamber of the frame by the cover, it is not necessary to insert-mold the lead frame during manufacture. Thereby, the metal mold | die containing a movable pin becomes unnecessary and can aim at the cost reduction of a metal mold | die. In addition, since the cover covers the frame with the arm mounted with the magnet holder inserted through the insertion hole, one side wall of the cover is sealed by one wall surface of the lead chamber, and the arm comes out of the magnet holder. Another wall can prevent that. For this reason, in manufacturing, it is only necessary to insert one end of the arm into the insertion hole without press-fitting the arm into the magnet holder, and a press machine for press-fitting is not required, thereby reducing the cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view showing a non-contact type liquid level sensor according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the non-contact type liquid level sensor according to the embodiment of the present invention. FIG. 3 is an exploded perspective view showing a method of attaching the lead frame assembly of the non-contact type liquid level sensor according to the embodiment of the present invention to the frame. FIG. 4 is an exploded perspective view showing a method of mounting the magnet assembly of the non-contact type liquid level sensor according to the embodiment of the present invention on the frame. FIG. 5 is an exploded perspective view showing a method of assembling the magnet assembly of the non-contact type liquid level sensor according to the embodiment of the present invention. FIG. 6 is an exploded perspective view showing a method of attaching the cover to the frame of the non-contact type liquid level sensor according to the embodiment of the present invention.

  The non-contact type liquid level sensor 10 of this embodiment is for detecting the liquid level of liquid such as gasoline, and includes a frame (housing) 11, a lead frame assembly 12, a magnet assembly 13, and a float. An assembly 14 and a cover 15 are provided.

  The frame (housing) 11 is formed by a general molding method, for example, injection molding or the like using an appropriate resin material, and an open portion (a lead to be described later) on one side (the back surface T in FIGS. 1 and 2). The lead frame assembly 12 is positioned and mounted in the chamber 11B), and the magnet assembly 13 is positioned and supported on the opposite surface (surface H in FIGS. 1 and 2) in a rotatable state.

  As shown in FIGS. 3 and 4, the frame 11 of the present embodiment is a thin box shape with one surface side opened (the opened portion in the frame 11 may be referred to as an opening portion), and the back surface. On the T (left side in FIG. 3, right side in FIG. 4) side, a pair of left and right lead chambers 11B surrounded by standing walls 11A parallel to the longitudinal (Y) direction (partially in the Z direction) is formed. A lead frame assembly 12 is accommodated in the chamber 11B. As a result, the lead frame assembly 12 is housed in the lead chamber 11B of the frame 11 so as not to protrude outward from the frame 11. Therefore, when the cover 15 to be described later is attached to the frame 11, the cover 15 is lead-free. It is possible to avoid the trouble that the mounting operation cannot be performed well by being locked to a part of the frame assembly 12.

  Since the electronic component welded to the lead frame assembly 12 is then resin-sealed, for example, when the cover 15 is attached to the frame 11, something is directly attached to the electronic component of the lead frame assembly 12. It can also be avoided that the electronic components are damaged by contact.

  Further, as shown in FIG. 3, a plurality of pins 11C are erected on the back surface T of the frame 11 in the lead chamber 11B. These pins 11C are formed of an appropriate resin that melts at a predetermined temperature. For example, in this embodiment, the pins 11C correspond to the positioning holes 161 that open in the lead frames 16A to 16C of the lead frame assembly 12. It is formed at an appropriate position by integral molding with the frame 11. As a result, after the pin 11C is inserted and positioned in a positioning hole 161 opened in a position corresponding to the pin 11C of the lead frame assembly 12 to be described later, the pin 11C is heated and melted and then solidified. Stop.

  Further, as shown in FIG. 4, the frame 11 of the present embodiment has a magnet assembly 13, which will be described later, below the center of the opposite surface (left surface in FIG. 4, hereinafter referred to as “surface H”). It is designed to be held in a rotatable state. For this reason, the frame 11 is provided with a central axis 11D serving as the center of rotation, a standing circular wall 11E, and two arcuate walls 11F whose phases are shifted by approximately 180 degrees concentrically.

  A magnetoelectric conversion element 11G is installed in the vicinity of the arcuate wall 11F outside the circular wall 11E in order to detect the amount of rotation of a magnet 18, which will be described later, which is the main body of the magnet assembly 13. When the magnetic flux density passing through the conversion element 11G changes, the magnetoelectric conversion element 11G detects this, converts it into an electrical signal, and outputs it to the outside. The frame 11 has a step (step) 11H. On the other hand, a pair of gripping portions 15D are provided at the intermediate portions on both side surfaces of the cover 15, and when the cover 15 is extrapolated from the longitudinal direction of the frame 11, the gripping portion 15D of the cover 15 is locked to the step 11H.

  The lead frame assembly 12 shown in FIG. 3 is formed by welding an electronic component 17 to a lead frame 16 and is housed in the lead chamber 11B of the frame 11 as described above. The lead frame 16 of the present embodiment is composed of lead frames 16A to 16C and the like, and a positioning hole 161 is provided at a predetermined position corresponding to the pin 11C of the frame 11 to insert the pin 11C. Open. The electronic component 17 is composed of components 17A to 17C, and these components 17A to 17C are welded to the lead frames 16A to 16C by appropriate welding means, and are attached to the lead chamber 11B in the frame 16, respectively. The resin is sealed by filling the adhesive.

  The magnet assembly 13 shown in FIG. 4 has the magnet 18 accommodated in a magnet holder 19 that integrally accommodates the magnet 18. The magnet assembly 13 of the present embodiment has a configuration in which the magnet 18 and the magnet holder 19 are integrally assembled by claw fixing described later. As described above, the magnet assembly 13 is attached to the central axis of the surface of the frame 11. 11D is supported in a rotatable state.

  As shown in FIG. 5, the magnet 18 of the present embodiment is a ferrite magnet or the like formed in a cylindrical shape with an appropriate magnetic material, and is provided with a claw 18 </ b> A that protrudes from a part of the outer peripheral surface. The projecting claw 18A not only functions as a detent for the magnet holder 19, but also generates a partial bias in the magnetic field distribution when the magnetic field is generated. In other words, the phase position can be accurately detected.

  On the other hand, the magnet holder 19 of this embodiment shown in FIG. 5 has a central hole 19A that is rotatably supported on the central axis 11D of the frame 11 at the center on one surface (the back surface T, which is the left surface in FIG. 5). And a storage chamber 19C for storing a magnet 18 separated by a cylindrical partition wall 19B surrounding the center hole 19A, are provided concentrically. A locking groove 19D for locking the claw 18A is provided. Further, when the storage chamber 19C is supported by the central axis 11D of the frame 11, the magnet 18 is covered by the wall surface of the storage chamber 19C and the circular wall 11E of the frame 11. Is fixed inside the storage chamber 19C.

  As described above, the magnet 18 and the magnet holder 19 of the present embodiment have a claw fixing structure that accommodates the magnet 18 in the accommodation chamber 19C in a state where the claw 18A is engaged with the locking groove 19D. A magnet 18 is assembled to a magnet holder 19 and fixed integrally. In the present embodiment, the holder 19 is provided with the locking groove 19D and the magnet 18 is provided with the claw 18A that engages with the locking groove 19D. It is good also as a structure which provides a nail | claw in the direction of the magnet holder 19 while providing a groove | channel.

  Further, as shown in FIG. 4, the magnet holder 19 is provided with an end A1 of an arm A of the float assembly 14 to be described later on the opposite surface (left surface in FIG. 4; hereinafter referred to as “surface H”). An insertion hole 19E for insertion and a holding portion 19F provided with a holding groove 19G for holding the held portion A2 of the arm A on the outer peripheral surface at the center of the magnet holder 19 are provided. The insertion hole 19E is a hole formed in the direction from the magnet holder 19 toward the frame 11 when the magnet holder 19 is rotatably supported by the central axis 11D. In FIG. 4, the magnet holder 19 is attached to the central axis 11D. A hole is drilled in parallel to the direction of mounting. In addition, the holding portion 19F has a direction of the insertion hole 19 formed in the magnet holder 10 in order to hold the held portion A2 connected perpendicularly to the one end A1 of the arm A inserted into the insertion hole 19E. It is formed by two ridges extending in a direction orthogonal to.

  On the other hand, the float assembly 14 shown in FIG. 2 has the float A attached to the arm A having one end A1 set on the magnet 18 of the magnet holder 19 supported by the frame 11 and the other end A3 of the arm A so as to be rotatable. F.

  In FIG. 2, a part of the arm A that is bent 90 degrees downward from the one end A <b> 1 (hereinafter referred to as a held portion A <b> 2) is held in a holding groove 19 </ b> G of the magnet holder 19. In this state, the magnet holder 19 is supported (see FIG. 1). Further, the held portion A2 and the holding portion 19F that holds the held portion A2 are accommodated in a space sandwiched between concentric arcuate walls 11F when the magnet holder 19 is supported by the frame 11. In addition, when the cover 15 is attached to the frame 11, an inner peripheral surface of a surrounding portion 15B of the cover 15 described later is provided so as to face the held portion A2 or the holding portion 19F. Of the held portion A2, the above-described sandwiched portion and storage portion are surrounded by a surrounding portion 15B, which will be described later, of the cover 15, and are pulled out from other portions, that is, the magnet holder 19 (frame 11). The protruding part protrudes from one end (the lower end in FIG. 4) of the frame 11.

  Further, since a cover 15 described later is extrapolated to the frame 11, the magnet holder 19 and the arm A supported by the frame 11 are prevented from being detached by the cover 15. Therefore, the arm A does not escape from the space surrounded by the arcuate wall 11F, in other words, the region between the pair of arcuate walls 11F (the range of about the central angle of 90 degrees). The held portion A2 rotates around the central axis 11D in accordance with the vertical movement. That is, when the float F moves up and down according to the water level of the liquid level, the arm A rotates according to this. For this reason, the magnet holder 19 and the magnet 18 integrated with the magnet holder 19 are also rotated about the central axis 11D of the frame 11 via the holding portion 19F that restrains the held portion A2.

  As shown in FIG. 6, the cover 15 is a state in which the float assembly 14 can rotate the magnet assembly 13 from the −Y (upward in FIG. 6) direction that is one end surface orthogonal to the front surface H and the back surface T of the frame 11. The frame 11 and the lead frame assembly 12 are integrally fixed to the nail by securing them to the frame 11 and securing them.

  The cover 15 of the present embodiment shown in FIG. 6 has a substantially hollow substantially box shape with the back plate side protruding, and is formed from a flat substrate portion 15A and one surface side of the substrate portion 15A toward the outside (X) direction. A hollow substantially box-shaped surrounding portion 15B that protrudes, a gripping portion 15D that grips the step 11H on both sides of the frame 11 from both front and back sides, and a claw 15C that is provided on both inner sides of the lower end of the surrounding portion 15B Are fixed to the frame 11 with the claws 15C. In the cover 15 of this embodiment, for example, in FIG. 6, the claws 15 </ b> C provided on the inner sides of the lower end portion of the surrounding portion 15 </ b> B are locked to the locking protrusions 11 </ b> J provided on the lower end portion of the frame 11. The cover 15 is nail-fixed to the frame 11, but is not particularly limited to this configuration.

  Contrary to the structure of the present embodiment, the frame 11 is provided with claws, and the cover 15 is provided with a groove or a locking projection for locking the claws so that the cover 15 and the frame 11 are hooked. A structure to be fixed may be used.

Next, a manufacturing method of the non-contact type liquid level sensor of the present embodiment will be described based on the above-described non-contact type liquid level sensor 10 with reference to the drawings.
As shown in FIG. 7, the manufacturing method of the non-contact type liquid level sensor according to this embodiment includes a welding step S1, a lead mounting step S2, a magnet mounting step S3, an arm mounting step S4, and a cover mounting step S5. And is composed of.

  In the welding step S1, the electronic component 17, for example, in this embodiment, as shown in FIG. 3, the components 17A to 17C are welded to the lead frames 16A to 16C, which are lead frames, to form the lead frame assembly 12. . Examples of the welding method here include solder, vibration welding, ultrasonic welding, and laser welding.

  In the lead mounting step S2, the lead frame assembly 12 to which the electronic component 17 is welded in FIG. 3 is mounted and accommodated while being positioned in the lead chamber 11B on the back surface T of the frame 11. Here, a specific mounting work process in the lead mounting step S2 will be described. As shown in FIG. 7, the lead mounting step S2 of the present embodiment includes a positioning step S21, a temporary fixing step S22, and a sealing step S23.

  Among these, in the positioning step S21, the lead frame is inserted into the pins 11C standing in the lead chamber 11B of the frame 11 by inserting the positioning holes 161 opened in the lead frames 16A to 16C of the lead frame assembly 12, respectively. The assembly 12 is physically positioned on the back surface T of the frame 11. Incidentally, as described above, the pins 11C standing on the back surface T of the frame 11 are integrally formed with the frame 11 in advance so as to correspond to the positioning holes 161 opened in the lead frames 16A to 16C of the lead frame assembly 12. Has been.

  Next, in the temporary fixing step S22, the pins 11C inserted into the positioning holes 161 of the lead frames 16A to 16C of the lead frame assembly 12 are heated and melted, respectively, and the molten resin is solidified. As a result, the lead frame assembly 12 is temporarily fixed to the frame 11. Here, the method of heating and melting the pin 11C is to raise only the pin 11C locally to the melting temperature of the resin so that the electronic component 17 and the like are not simultaneously heated and electrically destroyed. Any method can be used.

  Note that the positioning of the lead frame assembly 12 with respect to the frame 11 in the lead chamber 11B is usually not required to have such high accuracy. On the other hand, for example, there is a possibility that the position of the lead frame assembly 12 may be shifted from the melting of the pin to the solidification, but the contact state between the lead frames 16A to 16C and a terminal (not shown) on the frame 11 side must be removed. Good. For this reason, there is no particular problem if the temporary fixing operation is performed with the frame 11 lying horizontally, for example, without raising the frame 11 in the vertical direction in which gravity acceleration acts as shown in FIG. If there is, it may be fixed using an appropriate fixing jig or the like.

  Further, in the sealing step S23, after the lead frame assembly 12 is temporarily fixed in the temporary fixing step S22, an appropriate adhesive is filled and solidified in the lead chamber 11B on the back surface T of the frame 11, and the electronic component 17 and the lead frame assembly are fixed. 12 is resin-sealed. As a result, the lead frame assembly 12 in the temporarily fixed state is completely fixed in the lead chamber 11B on the back surface T of the frame 11, and the sealed resin causes damage to the electronic component 17 due to external contact or collision. It is possible to prevent the occurrence of a failure due to the deposition of a liquid or a vaporized gas whose liquid level is to be detected.

  In the magnet mounting step S3, as shown in FIG. 5, after forming the magnet assembly 13 in which the magnet 18 and the magnet holder 19 are assembled together, the magnet assembly 13 is attached to the back surface T of the frame 11 as shown in FIG. Is supported on the opposite surface H in a rotatable state. As a method for assembling the magnet 18 integrally with the magnet holder 19, in this embodiment, the claw fixing structure is used as shown in FIG. 5 described above, and the claw 18 A of the magnet 18 is attached to the locking groove 19 D of the magnet holder 19. The magnet 18 is accommodated in the accommodating chamber 19 </ b> C of the magnet holder 19.

  In the arm mounting step S4, one end of the arm A is set on the magnet holder 19 mounted on the frame 11. Here, as a method of attaching the arm A to the magnet holder 19, in this embodiment, as shown in FIG. 4, one end A1 of the arm A is inserted into the insertion hole 19E of the magnet holder 19 and the arm A is covered. The holding portion A2 is clamped in a clamping groove 19G provided in the holding portion 19F of the magnet holder 19. As a result, as described above, the arm A can be pulled out from the lower end (see FIG. 1) side with respect to the frame 11 and can be rotated in accordance with the vertical movement of the float F.

  In the cover mounting step S5, as shown in FIG. 6, the cover 15 is mounted by extrapolating from the upper end portion orthogonal to the front and back surfaces of the frame 11 while sliding to the frame 11. Thereby, the frame 11 and the lead frame assembly 12 can be fixed and held together. Further, the magnet assembly 13 and the arm A can be prevented from coming off simultaneously with the arm A being held in a rotatable state.

  Here, as a method of attaching the cover 15 to the frame 11 by extrapolation, in the case of this embodiment, as shown in FIG. 6, the inner peripheral surface (4 By sliding the surfaces α, β, γ, and δ) along the four surfaces (P, Q, R, and S) of the frame 11, a smooth extrapolation operation can be performed. Finally, the cover 15 is fixed to the frame 11 by locking the claw 15C provided at the lower end of the surrounding portion 15B to the locking projection 11J of the frame 11. For this reason, the cover 15 is prevented from sliding beyond a certain amount, thereby preventing the cover 15 from falling off.

  As described above, according to the non-contact type liquid level sensor according to the present embodiment of the present invention, the lead frame assembly 12 is temporarily fixed to the frame 11 by melting and then solidifying the pin 11C through which the frame 16 is inserted. Can be made. Furthermore, since the lead frame assembly 12 is securely fixed to the frame 11 by extrapolating the cover 15 to the frame after that, it is not necessary to insert the lead frame assembly. This eliminates the need for a mold with movable pins, reduces the cost of the mold, and realizes automation of the molding operation.

  Furthermore, since the arm A is set on the magnet holder 19 and then the cover 15 is used to prevent the arm A from coming off, no press-fitting work is required, and a press machine for press-fitting is not required, thereby reducing costs. Moreover, since the cover 15 is nail-fixed to the frame 11, it is not necessary to bond and fix the cover 15 to the frame 11, and an adhesive dispenser and a thermostatic bath are not required, thereby further reducing costs.

  Moreover, since the cover 15 covers the frame 11 with the arm A mounted with the magnet holder 19 inserted through the insertion hole 19E, one wall surface of the cover 19 seals one open side surface of the lead chamber 11B. The other wall can prevent the arm A from coming out of the magnet holder 19. For this reason, at the time of manufacture, it is only necessary to insert the one end A1 of the arm A into the insertion hole without press-fitting the arm A into the magnet holder 19, and a press machine for press-fitting is not required, thereby reducing the cost.

  Further, since the rotation of the arm A about the one end A1 of the arm A is effectively transmitted to the magnet holder 19 by the holding groove 19G, the one end A1 of the arm A is firmly fixed to the insertion hole 19E. There is no need to insert one end A1 of the arm A into the insertion hole 19E. For this reason, the man-hour required in order to manufacture a non-contact-type liquid level sensor can be reduced.

  In the non-contact type liquid level sensor according to this embodiment of the present invention, the one end A1 of the arm A inserted through the insertion hole 19E and the held portion A2 of the arm A sandwiched by the holding groove 19G However, the method of bending the arm A is not limited to this. What is important is that even when the arm A is bent at a plurality of locations, the magnet holder 19 is the most of the bent portions of the arm A that are accommodated by the cover 15 and whose one end A1 is fixed to the magnet holder 19. That is, one wall surface δ of the cover 15 faces a bent portion at a position away from the center. Thereby, the cover 15 can prevent the arm A from coming out of the magnet holder 19 and can prevent the magnet holder 19 to which the arm A is fixed from coming out of the central shaft 11D. On the other hand, as in the non-contact type liquid level sensor according to the present embodiment of the present invention, a bent portion in which the cover 15 only accommodates a bent portion in which the one end A1 of the arm A and the held portion A2 are orthogonal to each other. With this configuration, the volume inside the cover 15 can be minimized, so that the cover 15 can be downsized.

The front view which shows the non-contact-type liquid level sensor which concerns on embodiment of this invention 1 is an exploded perspective view of a non-contact type liquid level sensor according to an embodiment of the present invention. The disassembled perspective view which shows the method of mounting | wearing the lead frame assembly of the non-contact-type liquid level sensor which concerns on embodiment of this invention to a flame | frame. FIG. 4 is an exploded perspective view showing a method of mounting a magnet assembly or the like of a non-contact type liquid level sensor according to an embodiment of the present invention to a frame. The disassembled perspective view which shows the assembly method of the magnet assembly of the non-contact-type liquid level sensor which concerns on embodiment of this invention. The disassembled perspective view which shows the method of mounting | wearing with the cover to the flame | frame of the non-contact-type liquid level sensor which concerns on embodiment of this invention. It is a flowchart which shows the manufacturing method of the non-contact-type liquid level sensor which concerns on embodiment of this invention. Vertical section of a conventional non-contact type liquid level sensor The perspective view which shows the positional relationship of a magnetoelectric conversion element, a magnet, and a stator extracted from the non-contact-type liquid level sensor of FIG. The principal part expanded sectional view which shows the state by which the magnet cover of the conventional non-contact-type liquid level sensor shown in FIG. 8 was attached to the magnet chamber. It is a perspective view which shows the lead frame assembly of another conventional non-contact-type liquid level sensor. (A) And (B) is explanatory drawing which shows the method of integrally forming the conventional lead frame assembly with a flame | frame by insert molding. It is a perspective view which shows the conventional flame | frame integrally molded by the method shown in FIG. It is a disassembled perspective view which shows the assembly | attachment state of the conventional flame | frame shown in FIG. 13, a magnet assembly, and an arm.

Explanation of symbols

10 Non-contact type liquid level sensor 11 Frame 11B Lead chamber 11C Pin 11D Central axis 11E Circular wall 11F Arc wall 11G Magnetoelectric transducer 11H Step 11J Locking projection 12 Lead frame assembly 13 Magnet assembly 14 Float assembly 15 Cover 15A Substrate 15B Enclosure 15C Claw 15D Grip 16A-16C Lead frame 161 Positioning hole 17 Electronic component 17A-17C Component 18 Magnet 19 Magnet holder 19E Insertion hole 19F Holding portion 19G Holding groove A Arm A1 One end A2 Hold portion A3 Other end F float

Claims (3)

A lead frame with electronic components attached;
A magnet holder that houses the magnet inside;
A frame having a lead chamber in which the lead frame is mounted, an opening opened on one side surface of the lead chamber, and a central shaft that rotatably supports the magnet holder;
An arm having one end fixed to the magnet holder and having the other end attached to a float that moves up and down according to the level of the liquid level;
A cover attached to the lead frame so as to accommodate the frame in which the lead frame is attached to the lead chamber and the magnet holder to which the arm is fixed is rotatably supported;
With
The opening is provided on one side of the frame, and the central axis is provided on the other side of the frame located opposite to the one side;
The magnet holder has an insertion hole that is drilled in a direction from the magnet holder toward the frame when the magnet holder is rotatably mounted on the central axis, and through which one end of the arm is inserted,
The arm is fixed to the magnet holder so that one end portion of the arm passes through the insertion hole, and has a bent portion at at least one position from one end portion to the other end portion of the arm,
One wall surface of the cover attached to the frame so as to accommodate the frame therein forms one side surface of the lead chamber by facing the opening, and a wall surface opposite to the one wall surface is The one end of the arm holds the insertion hole through the insertion hole by facing the furthest part of the arm accommodated by the cover that is farthest from the magnet holder.
A non-contact type liquid level sensor. The magnet holder has a holding groove provided on the outer peripheral surface of the magnet holder and extending in a direction perpendicular to the direction of the insertion hole formed in the magnet holder;
The arm is fixed to the magnet holder so that one end portion of the arm passes through the insertion hole, and a part of the arm perpendicular to the one end portion of the arm is narrowed by the holding groove by the bent portion. Held,
The wall surface opposite to the one wall surface faces a part of the arm held by the holding groove, thereby maintaining a state where one end of the arm is inserted through the insertion hole.
The non-contact type liquid level sensor according to claim 1. The frame has a locking projection for fixing the cover attached from above in the longitudinal direction of the frame on the outer peripheral surface of the frame,
The cover has a locking claw locked to the locking projection at a position facing the locking projection when the cover is mounted from above in the longitudinal direction of the frame on the inner peripheral surface of the cover. ,
The non-contact type liquid level sensor according to claim 1 or 2, wherein

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