JP2010203839A - Noncontact type liquid level sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noncontact type liquid level sensor capable of protecting a detection circuit component group on a sensor housing without using a cover member which is different from the sensor housing. <P>SOLUTION: In this noncontact type liquid level sensor 31, a protection wall 47 made of a resin for covering and protecting the upper part of the detection circuit component group 45 assembled with the sensor housing 33 made of a resin is formed collectively with the sensor housing 33 by insert molding of the sensor housing 33, to thereby enable protection of the detection circuit component group 45 without using a cover member which is different from the sensor housing 33. A connection member 39 working as a connection part of the other end of a float arm 43 by being fitted and mounted onto a toroidal magnet is not required to be prevented from slipping-out by a different cover member, because a plurality of engaging projection pieces 61 provided on the outer circumference of a cylindrical part 39a fitted externally around the magnet prevents slipping-out from the sensor housing 33 by engagement with a circumferential engaging groove on the sensor housing 33 side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  According to the present invention, an annular magnet rotatably mounted on the sensor housing is rotated by the behavior of a float that moves up and down in accordance with the displacement of the liquid level to be measured, and the magnet is rotated along with the rotation of the magnet. The present invention relates to a non-contact type liquid level sensor that detects a liquid level by detecting a change in magnetic flux density generated around by a detection circuit component group assembled in the sensor housing.

15 and 16 show a conventional example of the non-contact type liquid level sensor.
The non-contact type liquid level sensor 1 shown here includes a resin sensor housing 3, a rotating shaft 5 that is rotatably assembled to the sensor housing 3, and an outer periphery of the rotating shaft 5. A ring-shaped magnet 7 that is rotatably mounted to 3, a connecting member (holder) 9 that is engaged with the magnet 7 so as to be integrally rotatable, and a float 11 that moves up and down in accordance with the displacement of the liquid level to be measured; One end 13 a is connected to the float 11 and the other end 13 b is connected to the connecting member 9, and the float arm 13 that converts the vertical movement of the float 11 into the rotation of the magnet 7, and the magnet incorporated in the sensor housing 3. A detection circuit component group 15 that detects a change in magnetic flux density generated in the stator around the magnet 7 with rotation of the magnet 7 and outputs it as an electrical signal; It is provided.

As shown in FIG. 15, the connecting member 9 includes a cylindrical portion 9 a that is externally fitted to the magnet 7, and a top plate portion that is integrally formed on one end side of the cylindrical portion 9 a so as to close one end side opening of the cylindrical portion 9 a. 9b and an arm coupling portion 9c that is integrally formed with the top plate portion 9b and serves as a coupling portion at the other end of the float arm 13.
On the inner side of the cylindrical portion 9a, there is provided a coupling portion that engages with a projection 7a formed on the outer surface of the magnet 7 and couples the connecting member 9 and the magnet 7 so as not to be relatively rotatable.

The connecting member 9 has a cap-like shape that fits to the outer periphery of the magnet 7 as a whole, and also serves to cover and protect the exposed surface of the magnet 7 to the outside.
As shown in FIG. 15, the connecting member 9 covers the rotating shaft 5 on the sensor housing 3 from the surface side of the sensor housing 3 with the magnet 7 previously engaged in the cylindrical portion 9 a. Then, the magnet 7 is fitted to the rotating shaft 5 and the connecting member 9 is rotatably attached to the sensor housing 3.
However, the connecting member 9 fitted to the rotary shaft 5 is not prevented from coming off from the sensor housing 3.

  The arm coupling portion 9c includes an arm engagement groove 9d extending in the diameter direction on the surface of the top plate portion 9b, and an arm end insertion hole 9e extending in the central axis direction of the magnet 7 on one end side of the arm engagement groove 9d. The other end 13b of the float arm 13 can be coupled so as not to be relatively rotatable.

  The float arm 13 is formed by bending a thin metal rod, and one end 13 a of the float arm 13 is connected to the float 11 by attaching a retaining ring 17 to a tip portion of the float 11 inserted through the through hole 11 a. Further, the other end 13 b of the float arm 13 is coupled to the coupling member 9 so as not to rotate relative to the coupling member 9 by engaging with the arm coupling portion 9 c of the coupling member 9.

  As shown in FIG. 16, the detection circuit component group 15 is configured by connecting a magneto-electric conversion element such as a Hall element or Hall IC, or a component 22 such as a resistor or a capacitor, to a circuit member 21 made of a metal plate. Thus, a change in magnetic flux density generated in the stator around the magnet 7 as the magnet 7 rotates is detected and output as an electrical signal to the external connection terminal portion 21a at the tip of the circuit member 21.

  If the detection circuit component group 15 is in an exposed state, the component 22 may be damaged due to interference with external equipment or the like, or the electrical connection portion of the component 22 may be damaged. Therefore, a structure for protecting the detection circuit component group 15 from the outside is required.

  Therefore, as a protection structure for the detection circuit component group, a structure in which a resin cover member that covers the detection circuit component group is attached to the sensor housing is widely used (see Patent Document 1 below).

  The non-contact type liquid level sensor 1 shown in FIG. 15 also includes a cover member 25 fitted and mounted on the sensor housing 3 from above as a structure for protecting the detection circuit component group 15 from the outside.

  The cover member 25 is connected to the back cover portion 25a that covers the detection circuit component group 15 and protects the detection circuit component group 15 and covers the connection member 9 when the sensor housing 3 is fitted and mounted. The member 9 and the other end 13b of the float arm 13 have a substantially cylindrical structure provided with a front cover portion 25b that prevents the sensor housing 3 from falling off and a side cover portion 25c that overlaps the side surface of the sensor housing 3. Yes.

JP 2004-037197 A

  However, in the structure in which the detection circuit component group 15 is protected from interference with the outside using the cover member 25 separate from the sensor housing 3 as described above, the cost of manufacturing the separate cover member 25 is high. In addition, since the cover member 25 is assembled to the sensor housing 3, there is a problem that the number of assembling steps increases.

  In addition, in the non-contact type liquid level sensor configured to detect a change in magnetic flux density according to the rotation of the annular magnet 7, the rotation axis of the magnet 7 is inclined in order to improve the detection accuracy. It is desirable to improve the support strength and positioning accuracy with respect to the connecting member 9 and the magnet 7 that rotate integrally with the magnet 7 so that there is no such problem.

  However, in the non-contact type liquid level sensor 1 shown in FIG. 15, the connecting member 9 and the magnet 7 are supported only by fitting with the rotating shaft 5 having a smaller diameter than the magnet 7. In addition, there is a problem that it is difficult to improve the support strength and positioning accuracy of the magnet 7.

  An object of the present invention is to solve the above problems, and can detect a detection circuit component group assembled to a sensor housing from interference with the outside without using a cover member separate from the sensor housing. By providing a non-contact liquid level sensor that can reduce costs and reduce the number of assembly processes by reducing the number of separate cover members, and by improving the support strength and positioning accuracy of connecting members and magnets An object of the present invention is to provide a non-contact type liquid level sensor capable of improving detection accuracy.

The above-described object of the present invention is achieved by the following configuration.
(1) Resin-made sensor housing, an annular magnet rotatably mounted on the sensor housing, a connecting member engaged with the magnet so as to rotate integrally, and depending on the displacement of the liquid level to be measured A float that moves up and down, a float arm that has one end connected to the float and the other end connected to the connecting member, and converts the vertical movement of the float into rotation of the magnet, and is incorporated in the sensor housing A detection circuit component group that detects a change in magnetic flux density generated in the magnet as the magnet rotates and outputs an electrical signal; and a resin protective wall that covers and protects the detection circuit component group. A non-contact type liquid level sensor provided,
The protective wall is integrally formed with the sensor housing by insert molding the detection circuit component group into the sensor housing.
The sensor housing includes a flange portion that forms an engagement groove around the magnet, and a notch communicating with the engagement groove is provided in a circumferential direction of the flange portion,
The connecting member includes a cylindrical portion that is externally fitted to the magnet, and an arm coupling portion that is integrally formed on one end side of the cylindrical portion and that couples the other end of the float arm so as not to be relatively rotatable. When the connecting member is abutted on the flange at the mounting start position, the notch is inserted and falls to the engagement groove side, and the connecting member is rotated to one side in that state. When operated, an engagement protrusion is provided that engages with the engagement groove in a freely rotating manner and regulates the disconnection of the connecting member from the sensor housing.
The non-contact type liquid level sensor, wherein the coupling member and the magnet are prevented from being detached from the sensor housing by the engagement between the engagement groove and the engagement protrusion.

(2) The sensor housing includes, on the outer surface portion of the flange portion, a step portion for preventing reverse rotation that restricts overcoming of a member moving from the opposite direction,
When the connecting member is rotated by a predetermined angle to one side while the engaging protrusion is engaged with the engaging groove, the connecting member gets over the stepped portion for reverse rotation. With a reverse stop protrusion,
The non-contact type liquid according to (1) above, wherein the connection member is prevented from rotating backward to the attachment start position by the engagement of the reverse rotation prevention protrusion and the reverse rotation prevention step portion. Surface level sensor.

According to the configuration of (1) above, the resin protective wall that covers the detection circuit component group attached to the sensor housing and protects the detection circuit component group is formed integrally with the sensor housing by insert molding of the sensor housing. Therefore, the detection circuit component group can be protected from interference with the outside without using a cover member separate from the sensor housing.
Therefore, the cost can be reduced by reducing the number of separate cover members, and the number of assembly steps can be reduced.

  In addition, the connecting member that is fitted and attached to the annular magnet and serves as the connecting portion at the other end of the float arm has an engaging protrusion provided on the outer periphery of the cylindrical portion that is externally fitted to the magnet. Since the engagement with the groove serves to prevent the sensor housing from coming off, there is no need to prevent the connecting member from coming off with a separate cover member.

  Further, the engaging protrusion on the outer peripheral portion of the cylindrical portion of the connecting member functions as a support mechanism that rotatably connects the connecting member to the sensor housing by engaging with the engaging groove on the sensor housing side. The engagement protrusion located on the circumference of the larger diameter than the magnet functions as a support mechanism, so that the support strength and positioning accuracy of the connection member and magnet can be improved. The detection accuracy can be improved by improving the strength and positioning accuracy.

  According to the configuration of (2) above, the connecting member is prevented from coming off from the sensor housing by inserting the engaging protrusion on the outer periphery of the connecting member into the engaging groove side from the notch of the flange portion on the sensor housing side. This is achieved by turning the member by an appropriate angle and restricting the engagement protrusion from being pulled out by the flange portion. However, as it is, when the connecting member turns in the opposite direction and the engagement protrusion returns to the notch position. The connecting member may fall out of the sensor housing. However, in the above configuration, when the connecting member is turned to a predetermined angle to prevent the connecting member from coming off, the anti-reverse protrusion provided on the connecting member is engaged with the step part for anti-reverse on the sensor housing side, Since the turning of the connecting member in the reverse direction is prevented, the state in which the connecting member and the magnet are rotatably supported by the sensor housing within a predetermined rotation range can be stably maintained.

According to the non-contact type liquid level sensor of the present invention, the detection circuit component group can be protected from interference with the outside without using a cover member separate from the sensor housing.
Further, it is not necessary to prevent the connecting member from being detached by a separate cover member.
Therefore, the cost can be reduced by reducing the number of separate cover members, and the number of assembly steps can be reduced.

  Further, it becomes possible to improve the support strength and positioning accuracy of the connecting member and the magnet, and the detection accuracy can be improved by improving the support strength and positioning accuracy of the connecting member and the magnet.

It is a disassembled perspective view of one Embodiment of the non-contact-type liquid level sensor which concerns on this invention. It is a disassembled perspective view which shows the structure of the detection circuit components group assembled | attached to the sensor housing shown in FIG. It is the perspective view seen from the front side of the sensor housing shown in FIG. It is a front view of the sensor housing shown in FIG. It is AA sectional drawing of FIG. It is a bottom view of the connection member shown in FIG. It is a perspective view from the arrow B direction of the connection member shown in FIG. It is a top view of the connection member shown in FIG. It is a perspective view from the arrow C direction of the connection member shown in FIG. (A) is a side view of the state in which the engaging protrusion of the connecting member is engaged with the engaging groove of the sensor housing, but before the reverse rotation protrusion protrudes over the step for reverse rotation. FIG. 6 is a side view of a state in which the connecting member is turned to a predetermined angle from one state a) and the reverse rotation prevention protrusion has climbed over the reverse rotation prevention stepped portion. It is the perspective view seen from the lower surface side of other embodiment of the connection member used for the non-contact-type liquid level sensor which concerns on this invention. It is a top view of the connection member shown in FIG. It is a perspective view from the arrow D direction of FIG. It is E arrow line view of FIG. It is a disassembled perspective view of the conventional non-contact-type liquid level sensor. It is a disassembled perspective view of the conventional non-contact-type liquid level sensor.

Hereinafter, a preferred embodiment of a non-contact type liquid level sensor according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view of an embodiment of a non-contact type liquid level sensor according to the present invention, FIG. 2 is an exploded perspective view showing a configuration of a detection circuit component group assembled to the sensor housing shown in FIG. 1 is a perspective view seen from the front side of the sensor housing shown in FIG. 1, FIG. 4 is a front view of the sensor housing shown in FIG. 3, FIG. 5 is a sectional view taken on line AA in FIG. FIG. 7 is a perspective view of the connecting member shown in FIG. 6 from the direction of arrow B, FIG. 8 is a top view of the connecting member shown in FIG. 1, and FIG. 9 is a connecting member shown in FIG. It is a perspective view from the arrow C direction.

  The non-contact type liquid level sensor 31 of this embodiment is mounted on a vehicle fuel tank or the like and used for detecting the amount of liquid such as fuel, and is made of a resin sensor housing 33, a sensor housing A magnet support shaft 35 projecting from the magnet housing space 33, an annular magnet 37 rotatably mounted on the sensor housing 33 by being rotatably fitted to the outer periphery of the magnet support shaft 35; A connecting member (holder) 39 engaged with the magnet 37 so as to be integrally rotatable, a float 41 that moves up and down according to the displacement of the liquid level to be measured, one end 43a is connected to the float 41, and the other end 43b A float arm 43 coupled to the coupling member 39 to convert the vertical movement of the float 41 into rotation of the magnet 37, and a sensor housing 33 A detection circuit component group 45 that detects a change in magnetic flux density generated in the stator around the magnet 37 as the magnet 37 rotates and outputs it as an electric signal, and covers and protects the detection circuit component group 45. A protective wall 47 made of resin.

  As shown in FIGS. 1 and 2, the connecting member 39 is integrally formed on one end side of the cylindrical portion 39 a so as to close the cylindrical portion 39 a that is externally fitted to the magnet 37 and one end side opening of the cylindrical portion 39 a. It has a top plate portion 39 b and an arm coupling portion 39 c that is integrally formed on the outer periphery of the cylindrical portion 39 a and serves as a coupling portion for the other end 43 b of the float arm 43.

  On the inner side of the cylindrical portion 39a, a coupling portion 40 (FIGS. 6 and 7) that engages with a protrusion 37a formed on the outer surface of the magnet 37 and couples the connecting member 39 and the magnet 37 so as not to rotate relative to each other. Reference) is provided.

The connecting member 39 has a cap-like shape that is fitted to the outer periphery of the magnet 37 as a whole, and also serves to cover and protect the outwardly exposed surface of the magnet 37.
As shown in FIG. 1, the connecting member 39 covers the magnet support shaft 35 on the sensor housing 33 from the surface side of the sensor housing 33 with the magnet 37 previously engaged in the cylindrical portion 39 a. Then, the magnet 37 is fitted to the magnet support shaft 35.

  Thereafter, the engagement protrusion 61 of the connecting member 39 described later is engaged with an engaging groove 51 described later of the sensor housing 33 so that the magnet 37 and the connecting member 39 are rotatably connected to the sensor housing 33. become.

  As shown in FIGS. 1 and 9, the arm coupling portion 39c is formed on the outer peripheral surface of the cylindrical portion 39a, and the arm engagement groove 39d into which the straight linear portion 43c of the other end 43b of the float arm 43 is interrupted. The other end 43b of the float arm 43 can be coupled to be relatively non-rotatable with a configuration including an arm end insertion hole 39e into which the other end 43b is fitted on one end side of the engagement groove 39d.

  The float arm 43 is formed by bending a thin metal rod, and one end 43 a of the float arm 43 is connected to the float 41 by attaching the retaining ring 17 to the tip end portion of the float 41 inserted through the through hole 41 a. Further, the other end 43 b of the float arm 43 is coupled to the coupling member 39 so as not to rotate relative to the coupling member 39 by engaging with the arm coupling portion 39 c of the coupling member 39.

  As shown in FIG. 2, the detection circuit component group 45 includes a metal plate circuit member (lead frame) 23 connected to magnetoelectric conversion elements such as Hall elements and Hall ICs, and components 22 such as resistors and capacitors. The detection device is configured to detect a change in magnetic flux density generated in the stator around the magnet 37 as the magnet 37 rotates, and output it as an electrical signal to an external connection terminal that is conductively connected to the circuit member 23.

  If the detection circuit component group 45 is in an exposed state, the component 22 may be damaged due to interference with external equipment or the like, or the electrical connection portion of the component 22 may be damaged. Therefore, a protective wall 47 made of resin for protecting the detection circuit component group 45 is provided. In the present embodiment, the protective wall 47 is formed by insert-molding the detection circuit component group 45 into the sensor housing 33 to thereby form the sensor housing 33. Are integrally formed.

  The sensor housing 33 shown in FIG. 1 shows a state in which the detection circuit component group 45 incorporated in the sensor housing 33 is covered with a protective wall 47 formed by insert molding.

  In the case of the present embodiment, as shown in FIGS. 3 to 5, the sensor housing 33 has a circumferential engagement groove 51 concentrically with the magnet 37 around the magnet 37 fitted to the magnet support shaft 35. And three notches 55 communicating with the engaging groove 51 are provided at three locations in the circumferential direction of the flange portion 53.

Further, the sensor housing 33 includes a pair of reverse-rotation-preventing step portions 57 and 58 for restricting the movement of the member moving from the opposite direction on the outer surface portion of the flange portion 53.
Here, the pair of reverse-rotation-preventing step portions 57 and 58 are set to inclined surfaces 57a and 58a on which one member can contact the moving member, and the other surface can not be overcome. The surfaces 57b and 58b are set.

  Specifically, the vertical surface 57b of the reverse rotation preventing step 57 prevents the member that rotates in the arrow X direction in FIG. 4 from getting over. Further, the vertical surface 58b of the reverse stop step 58 prevents the member that rotates in the arrow Y direction in FIG. 4 from getting over.

  On the other hand, as shown in FIGS. 6 to 9, the connection member 39 of the present embodiment includes three engagement protrusions 61 that engage with the engagement groove 51 of the sensor housing 33 described above, and a step for reverse rotation prevention. A reverse-rotation protrusion 63 that engages with the portion 57.

  The three engagement protrusions 61 are integrally formed near the lower surface of the outer periphery of the cylindrical portion 39a corresponding to the positions of the three notches 55 formed in the flange portion 53 of the sensor housing 33.

  The above three engagement protrusions 61 flange the connecting member 39 at the attachment start position with respect to the flange portion 53 (the position where the positions of the three engagement protrusions 61 and the three notches 55 overlap). When it is abutted on the portion 53, the notch 55 is inserted and falls to the engagement groove 51 side. When the connection member 39 is rotated to one side as shown in FIG. The connecting member 39 is prevented from coming off from the sensor housing 33 by being rotatably engaged.

  That is, in the non-contact type liquid level sensor 31 of the present embodiment, the coupling member 39 and the magnet 37 are prevented from being detached from the sensor housing 33 by the engagement between the engagement groove 51 and the engagement protrusion 61.

  As shown in FIG. 7, the reverse rotation prevention protrusion 63 is provided so as to protrude laterally from the top side of the cylindrical portion 39 a, and the engagement protrusion 61 engages with the engagement groove 51 as shown in FIG. 10. In this state, when the connecting member 39 is rotated to one side by a predetermined angle, the engagement state is reached over the reverse rotation preventing step portions 57 and 58 on the sensor housing 33 side.

  In the non-contact type liquid level sensor 31 of this embodiment, the connection member 39 is prevented from rotating backward to the mounting start position by the engagement between the reverse rotation prevention protrusion 63 and the reverse rotation prevention step portions 57 and 58 described above. Thus, the state in which the connecting member 39 and the magnet 37 are rotatably supported by the sensor housing 33 within a predetermined rotation range is maintained.

In the non-contact type liquid level sensor 31 of the embodiment described above, a protective wall 47 made of resin that covers the detection circuit component group 45 attached to the sensor housing 33 and protects the detection circuit component group 45 (see FIG. 1) is integrally formed with the sensor housing 33 by insert molding of the sensor housing 33, so that the detection circuit component group 45 is protected from external interference without using a cover member separate from the sensor housing 33. be able to.
Therefore, the cost can be reduced by reducing the number of separate cover members, and the number of assembly steps can be reduced.

  Further, in the non-contact type liquid level sensor 31 according to the embodiment, the connecting member 39 that is fitted and attached to the annular magnet 37 and serves as the connecting portion of the other end 43 b of the float arm 43 is externally fitted to the magnet 37. The plurality of engaging protrusions 61 provided on the outer periphery of the cylindrical portion 39a are prevented from coming off from the sensor housing 33 by engaging with the circumferential engaging groove 51 on the sensor housing 33 side. It is not necessary to prevent the connecting member 39 from being detached by the cover member.

  The plurality of engaging protrusions 61 on the outer peripheral portion of the cylindrical portion 39a of the connecting member 39 are engaged with the engaging groove 51 on the sensor housing 33 side so that the connecting member 39 and the magnet 37 can rotate freely. 33, the engagement protrusion 61 located on the circumference of the larger diameter than the annular magnet 37 functions as a support mechanism, so that the support strength of the connecting member 39 and the magnet 37 can be increased. The positioning accuracy can be improved, and the detection accuracy can be improved by improving the supporting strength of the connecting member 39 and the magnet 37 and the positioning accuracy.

  Further, in the non-contact type liquid level sensor 31, the connecting member 39 is prevented from coming off from the sensor housing 33 by connecting the plurality of engaging protrusions 61 on the outer periphery of the connecting member 39 to the flange 53 on the sensor housing 33 side. This is achieved by inserting the engagement member 51 from the notch 55 to the engagement groove 51 side and then turning the connection member 39 by an appropriate angle so that the engagement protrusion 61 is prevented from being pulled out by the flange portion 53. If the engaging protrusion 61 returns to the position of the notch 55 by turning in the opposite direction, the connecting member 39 may fall out of the sensor housing 33. However, in the above embodiment, when the connecting member 39 is turned to a predetermined angle to prevent the connecting member 39 from coming off, the reverse rotation protrusion 63 provided on the connecting member 39 has the reverse rotation preventing stepped portion on the sensor housing 33 side. Since the connecting member 39 is prevented from turning in the reverse direction by engaging with the members 57 and 58, the connecting member 39 and the magnet 37 are supported by the sensor housing 33 so as to be rotatable within a predetermined rotation range. It can be kept stable.

  In the non-contact type liquid level sensor 31 according to the present invention, the number of the engagement protrusions 61 provided in the connecting member 39 and the number of the notches 55 formed in the flange portion 53 of the sensor housing 33 are the same as those in the above embodiment. It is not limited to the quantity shown in. It is possible to set two or four or more. However, if the number of the engaging protrusions 61 and the cutouts 55 is small, the attachment of the connecting member 39 may be loose, causing the rotation axis of the magnet 37 to be inclined, and the engaging protrusions 61 and the cutouts 55. If the quantity is too large, it may be difficult to secure the rotation range of the connecting member 39 and the magnet 37 corresponding to the vertical movement range of the float 41.

  In the above embodiment, setting the number of the engagement protrusions 61 and the notches 55 to be three makes it difficult for the rotation axis of the magnet 37 to tilt, and the rotation range of the connecting member 39 and the magnet 37 is relatively large ( (For example, 100 degrees or more) can be ensured, and the setting can sufficiently exert the effect.

  Moreover, in the connecting member used for the non-contact type liquid level sensor 31 according to the present invention, the position and orientation of the anti-reverse protrusion can be appropriately changed in design and is not limited to the above embodiment.

  11 to 14 show other embodiments of the connecting member used in the non-contact type liquid level sensor 31 according to the present invention, and FIG. 11 shows the lower surface of the other embodiment of the connecting member according to the present invention. FIG. 12 is a top view of the connecting member shown in FIG. 11, FIG. 13 is a perspective view from the direction of arrow D in FIG. 12, and FIG. 14 is a view from arrow E in FIG.

The basic configuration of the connecting member 39A of this embodiment is the same as that of the connecting member 39 of the embodiment, and the same or corresponding components will be described with the same numbers.
The connecting member 39A of this embodiment also includes a cylindrical portion 39a that is externally fitted to the magnet 37, a top plate portion 39b that is integrally formed on one end side of the cylindrical portion 39a so as to close an opening on the one end side of the cylindrical portion 39a, and a cylinder. An arm coupling portion 39c that is integrally formed on the outer periphery of the portion 39a and serves as a coupling portion for the other end 43b of the float arm 43.

  Further, on the inner side of the cylindrical portion 39a, a coupling portion 40 (see FIG. 11) that engages with a protrusion 37a formed on the outer surface of the magnet 37 and couples the connecting member 39 and the magnet 37 so as not to rotate relative to each other. ) Is provided.

In addition, at the position near the lower surface of the cylindrical portion 39a, engagement protrusions 61 that are engaged with the engagement grooves 51 of the sensor housing 33 are provided at three positions in the circumferential direction.
Further, on the upper surface side of the cylindrical portion 39a, an anti-reverse protrusion 63 that engages with the anti-reverse step portions 57 and 58 of the sensor housing 33 to prevent rotation is extended.

  The connecting member 39A of this embodiment can be attached to the sensor housing 33 shown in FIGS. 3 to 5 by the same operation as that of the connecting member 39 shown in the embodiment. The same actions and effects can be obtained.

  The present invention is not limited to the above-described embodiments, and can be appropriately modified and improved. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

22 parts 23 circuit member 31, 31A non-contact type liquid level sensor 33 sensor housing 37 magnet 37a protrusion 39, 39A connecting member 39a cylindrical portion 39b top plate portion 39c arm coupling portion 39d arm engagement groove 39e arm end insertion hole 41 Float 43 Float arm 47 Protective wall 51 Engagement groove 53 Flange part 55 Notch 57, 58 Step part 57a, 58a for reverse rotation Inclined surface 57b, 58b Vertical surface 61 Engagement protrusion 63 Reverse rotation prevention protrusion

Claims (2)

Resin sensor housing, an annular magnet rotatably mounted on the sensor housing, a connecting member engaged with the magnet so as to rotate integrally, and a vertical movement according to the displacement of the liquid level to be measured A float that has one end connected to the float and the other end connected to the connecting member to convert the vertical movement of the float into rotation of the magnet, and is incorporated in the sensor housing to A detection circuit component group that detects a change in magnetic flux density generated in the magnet as it rotates and outputs it as an electrical signal, and a resin protective wall that covers and protects the detection circuit component group A contact-type liquid level sensor,
The protective wall is integrally formed with the sensor housing by insert molding the detection circuit component group into the sensor housing.
The sensor housing includes a flange portion that forms an engagement groove around the magnet, and a notch communicating with the engagement groove is provided in a circumferential direction of the flange portion,
The connecting member includes a cylindrical portion that is externally fitted to the magnet, and an arm coupling portion that is integrally formed on one end side of the cylindrical portion and that couples the other end of the float arm so as not to be relatively rotatable. When the connecting member is abutted on the flange portion at the mounting start position, the notch is inserted and falls to the engaging groove side, and the connecting member is rotated to one side in that state. When operated, an engagement protrusion is provided that engages with the engagement groove so as to be rotatable and restricts the connection member from being removed from the sensor housing.
2. The non-contact type liquid level sensor according to claim 1, wherein the coupling member and the magnet are prevented from being detached from the sensor housing by engagement between the engagement groove and the engagement protrusion. 3. The sensor housing includes, on the outer surface portion of the flange portion, a step portion for reverse rotation prevention that restricts overcoming of a member moving from the opposite direction,
When the connecting member is rotated by a predetermined angle to one side while the engaging protrusion is engaged with the engaging groove, the connecting member gets over the stepped portion for reverse rotation. With a reverse stop protrusion,
The non-contact type liquid surface according to claim 2, wherein the connection member is prevented from rotating backward to the attachment start position by engagement of the reverse rotation prevention protrusion and the reverse rotation prevention stepped portion. Level sensor.

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