JP2018169231A - Load transducer - Google Patents

Abstract

To provide a load converter excellent in response to the fluctuation of a load.SOLUTION: A load converter includes: a load reception part 2 for receiving a load at a first end surface 2b; a fixing part 3 for surrounding the load receiving part 2 at predetermined intervals in a columnar state having a hallow part; a strain part 6 for connecting the load reception part 2 and a middle part in the axial direction of the fixing part 3 in a thin thickness form; a plurality of load detection means G for detecting the load provided in the strain part 6; and an annular lid body 4 facing and nipping the strain part 6. The lid body has a first lid body 4a provided at a middle position between the first end face 2b and the strain part 6 and a second lid body 4b provided at the middle position between a second end surface 2e and the strain part 6. The load reception part 2 has a path for connecting a side peripheral surface of the load reception part 2 projected from the first lid body 4a and a portion of the load reception part 2 projected from the second lid body 4b.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a load converter that converts a load into an electrical signal.

    FIG. 6 is a sectional view showing an example of a conventional load converter (load cell). This load converter includes a cylindrical load receiving portion 2 that receives a load, a cylindrical fixing portion 3 that is provided so as to surround the outer surface of the cylindrical surface and is fixed to a fixed structure 12 by bolts 7, and a load receiving portion. 2 and a ring-shaped strain generating portion 6 composed of a thin portion connecting the fixing portion 3. A plurality of load detection means G are attached to the lower surface of the strain generating portion 6. The load detection means G is, for example, a strain gauge, the strain gauge on the outer side is a strain gauge for detecting compressive strain, and the strain gauge on the inner side is a strain gauge for detecting tensile strain. The load detection means G is affixed side by side in the radial direction with the thinnest thin part of the strain generating part 6 interposed therebetween. Load detection signals obtained from these load detection means G are output via the connector 5.

  The top surface of the load receiving portion 2 is a surface that directly receives a load. The second end surface 2 e forming the bottom surface of the load receiving portion 2 is formed so as to be slightly higher than the fixing surfaces of the fixed structure 12 and the fixing portion 3, that is, closer to the strain generating portion 6.

  A lid is provided between the inner side surface of the fixed portion 3 and the side surface of the load receiving portion 2 with the strain generating portion 6 interposed therebetween. The lid is made of an annular thin metal, and is welded or bonded to the load receiving portion 2 and the fixing portion 3 so as not to affect the elastic deformation of the strain-generating portion 6. Is provided. The lid is composed of a first lid 4 a on the upper side of the strain generating portion 6 and a second lid 4 b on the lower side of the strain generating portion 6. The load detection means G affixed to the strain generating part 6 by this lid is protected from the external environment.

JP, 2014-163877, A

  In this load converter, FIG. 7 shows a state at the time of deformation when receiving a load. The space 13 shown here is defined by the second end surface 2e of the load receiving portion 2, the second lid 4b, the cylindrical inner surface 3b of the fixed portion 3, and the top surface of the fixed structure 12. It is. If the sealing property between the top surface of the fixed structure 12 and the bottom surface of the fixed portion 3 is low, when the load receiving portion 2 receives a load, the space 13 is compressed and the top surface of the fixed structure 12 and the fixed portion 3 are fixed. Air is released from the interface at the bottom. Thereafter, when the load is removed, air flows from the interface into the space 13 and returns to the original state. Even in the case where the top surface of the fixed structure 12 and the bottom surface of the fixed portion 3 are highly sealed, the space 13 is not completely sealed and a slight amount of air enters and exits. It will take.

  Therefore, even when the load is removed after the space 13 is pressed and contracted by the load, the air does not instantaneously return to the space 13, and the space 13 remains negative pressure, and the load receiving portion 2 However, there is a problem that it takes time to return to the original position corresponding to the load applied at that time. Therefore, this load converter has room for improvement in response to load fluctuations.

  In view of such a problem, an object of the present invention is to provide a load transducer that is excellent in responsiveness to load fluctuations.

In order to achieve the above object, the load transducer according to claim 1
A substantially cylindrical load receiving portion that receives a load at the first end face;
Columnar shape having a hollow part constituted by the inner peripheral surface of the cylindrical surface, and arranged so as to surround the load receiving part in the hollow part, and so that the cylindrical side surface of the load receiving part and the inner peripheral surface have a predetermined interval A fixed part,
A strain generating portion that is elastically deformed by a load received by the load receiving portion by connecting the intermediate portions in the axial direction of the cylindrical side surface of the load receiving portion and the inner peripheral surface of the fixed portion in a thin shape,
A plurality of load detecting means provided in the strain generating portion for detecting a load received by the load receiving portion;
A flexible annular lid that is fixed to the load receiving part and the fixing part so as to sandwich the strain generating part relative to each other between the load receiving part and the fixing part;
A load transducer comprising:
A lid is provided on the first end surface of the load receiving portion in the axial direction of the load receiving portion, and a first lid provided at an intermediate position between the first end surface and the strain-generating portion in the axial direction of the load receiving portion. A second lid provided at an intermediate position between the opposing second end face and the strain-generating portion,
The load receiving portion is configured to include a passage that connects the side peripheral surface of the load receiving portion protruding from the first lid and the load receiving portion protruding from the second lid.

In order to achieve the above object, a load converter according to claim 2 is provided.
The load receiving portion includes an umbrella portion and a handle portion, and a first member having a mushroom shape that contacts the load application object at the umbrella portion, and surrounds the outer periphery of the handle portion of the first member and is engaged with the first member. A cylindrical second member to be joined,
The passage of the load receiving portion includes a cylindrical hollow portion of the second member and a recess provided on at least one engagement surface of the first member and the second member.

In order to achieve the above object, the load transducer according to claim 3 is:
The concave portion includes a portion in which the umbrella portion of the first member and the second member are provided in the radial direction on at least one of the surfaces facing each other in the axial direction.

  According to the load converter of the invention described in claim 1, the load receiving portion includes a side peripheral surface of the load receiving portion protruding from the first lid, a load receiving portion protruding from the second lid, It has a passage that connects the two. Therefore, when the load transducer is fixed, the space where the volume changes due to the movement of the load receiving portion caused by the application of the load and the elastic deformation of the strain generating portion, and the external space where the load transducer is placed This makes it easy for air to enter and exit. Therefore, the volume change speed of the space following the load change is increased, and a load converter excellent in responsiveness to the load change can be provided.

  According to the load converter of the invention described in claim 2, in addition to the above effects, the load receiving portion is composed of a plurality of members, and groove-shaped passages are arranged in each of them, so that the parts are processed and assembled. Can be provided.

  According to the load converter of the invention described in claim 3, in addition to the above-described effect, even if the load receiving portion is formed of a plurality of members and the engagement surface is in close contact, the engagement surface has a radius. Since it has the direction passage, it is possible to provide a load transducer that is excellent in air circulation and excellent in responsiveness.

1 is a perspective external view of a load converter according to a first embodiment of the present invention. It is a top view of a load converter concerning a 1st embodiment of the present invention. It is a Wheatstone bridge circuit diagram comprised by the load detection means in the load converter which concerns on the 1st Embodiment of this invention. It is a section lineblock diagram of a load converter concerning a 1st embodiment of the present invention. It is a perspective structure exploded view of the load converter which concerns on the 2nd Embodiment of this invention. It is sectional drawing structure which represented the conventional load converter typically. It is sectional drawing structure which represented typically the deformation | transformation when a load was added to the conventional load converter.

  Hereinafter, the load transducer according to the first embodiment of the present invention will be described in detail based on the drawings. FIG. 1 is a perspective external view of a load transducer according to a first embodiment of the present invention.

  The load converter 1 is mainly composed of a substantially cylindrical load receiving portion 2 that receives a load in contact with an applied load, and a substantially cylindrical fixed portion that is disposed on the side surface of the load receiving portion 2. 3, a strain generating portion 6 that connects the load receiving portion 2 and the fixing portion 3 with a thin wall, a first lid 4 a that is between the load receiving portion 2 and the fixing portion 3 and seals the inside, and an electric signal for the load And a round connector 5 for connecting a cable or the like for transmission to the outside.

  The load receiving portion 2 includes a mushroom-shaped first member 2a with which a load application object to be measured comes into contact, and a cylindrical second member 2d that engages with the first member 2a. . The curved surface of the umbrella part of the first member 2a is a part that abuts against an applied load and receives a load. The handle portion of the first member 2a is a portion that engages with the second member 2d.

  The fixed portion 3 has a columnar shape having a hollow portion constituted by an inner peripheral surface of a cylindrical surface, and the cylindrical side surface of the load receiving portion 2 and the inner peripheral surface of the hollow portion are at a predetermined interval and the load receiving portion 2. It is arrange | positioned so that the load receiving part 2 may be surrounded coaxially.

  FIG. 2 is a plan view showing the internal structure by omitting the first lid 4a and the like of the load converter according to the first embodiment of the present invention.

  The fixed portion 3 is fixed to a fixed structure 12 (see FIG. 4) with a plurality of, for example, three bolts 7 on a fixed surface 3a at the bottom of the cylinder. The fixed structure 12 is provided with a screw portion for attaching the bolt 7 and is not easily deformed by a load transmitted from the fixed portion 3.

  The second member 2d of the load receiving portion 2 has a cylindrical shape, and is screwed into a part of the inner wall surface 2f of the cylindrical hollow portion with a male screw provided on a handle portion of the mushroom-shaped first member 2a. A female screw is provided. The upper surface of the second member 2d is engaged with the first member 2a, and a passage groove 2g is provided in the radial direction on the engaging surface.

  A thin-walled shape is connected between the axial portions of the cylindrical surface outside the second member 2d of the load receiving portion 2 and the inner cylindrical surface of the fixed portion 3 surrounding the outer periphery in the axial direction. Beam-shaped strain generating portions 6a and strain generating portions 6b are provided. The strain generating portion 6a is composed of three beams on the first member 2a side (upper surface side) in the axial direction at intervals of 120 degrees in the circumferential direction. The strain generating portion 6b is composed of three beams on the opposite side (lower surface side) of the first member 2a in the axial direction at a position shifted from the strain generating portion 6a by 60 degrees in the rotation direction. The strain generating part 6a and the strain generating part 6b are all the same shape, and the upper surface side of the strain generating part 6a and the lower surface side of the strain generating part 6b are planar. The strain generating portion 6a and the strain generating portion 6b are supported by one of the beams supported by the fixed portion 3 that is fixed by the fixed structure 12 and is not easily deformed, and the load transmitted from the load receiving portion 2 connected to the other of the beams. It is elastically deformed. The arrangement and shape of the strain-generating portion 6 of this embodiment are examples, and are not limited to this as long as they have equivalent functions.

  Load detecting means G1c to G3c and load detecting means G1t to G3t for detecting a load transmitted from the load receiving portion 2 are attached to a plane on the upper surface side of the strain generating portion 6a. The load detection means G1c to G3c and the load detection means G1t to G3t are strain gauges in this embodiment, but are limited to this as long as they have a load detection function based on the deformation amount of the elastically deforming strained body. is not.

  The load detection means G4c to G6c and the load detection means G4t to G6t placed on the plane on the lower surface side of the strain generating portion 6b are represented by broken lines. Each load detecting means is affixed to each strain generating portion so that the maximum sensitivity direction with respect to strain is the radial direction. When the second member 2d of the load receiving portion 2 receives a load in the direction from the front to the back of the page, the load detecting means G1c to G3c attached to the inside of the strain generating portion 6a detect the compressive load, The load detection means G1t to G3t attached to the outside of the strained portion 6a detect the tensile load. On the other hand, the load detection means G4t to G6t affixed to the inside of the strain generation part 6b detect a tensile load, and the load detection means G4c to G6c affixed to the outside of the strain generation part 6b detect a compression load.

  FIG. 3 is a Wheatstone bridge circuit diagram including the load detecting means in the load converter according to the first embodiment of the present invention. The load detection means G1t to G3t and the load detection means G4t to G6t are detections of tensile loads, and are arranged in series. The sum of the load detection means G1t to G3t and the sum of the load detection means G4t to G6t, which are assembled in series, are arranged as opposite sides in the Wheatstone bridge. On the other hand, the load detection means G1c to G3c and the load detection means G4c to G6c are detections of compression loads, and these are also arranged in series. The sum of the load detection means G1c to G3c and the sum of the load detection means G4c to G6c, which are assembled in series, are also arranged as opposite sides in the Wheatstone bridge. When the power source E is applied between the terminals T1 and T3, the outputs S + and S− are converted into voltages that are electric signals between the terminals T2 and T4 and output. In this configuration, since each side is composed of three load detecting means, the entire resistance value is increased, the voltage of the power source E can be increased, and the outputs S + and S− can be increased. .

FIG. 4 is a sectional view showing the internal structure of the load transducer according to the first embodiment of the present invention.
The cut section is AA in FIG. 2, which is a vertical plane passing through the axial line of the circular connector 5.

  An annular metal lid support plate 9 is bonded to the fixed portion 3 on the upper side of the strain generating portion 6a. An annular lid support ring 10 made of metal having a rectangular cross section is bonded to the second member 2d. Then, the metal thin plate-shaped first lid 4a having flexibility is bonded or welded so as to cover the lid support plate 9 and the lid support ring 10, so that the fixing portion 3, the second member 2d, The lid support plate 9 and the lid support ring 10 are fixed.

  The wiring board 11 is below the strain generating portion 6 and is fixed by bonding or the like, and is connected to the load detection means G1c to G6c and the load detection means G1t to G6t to form a Wheatstone bridge circuit. Wiring is gathered by the wiring board 11, wiring (not shown) is performed between the wiring board 11 and the terminals of the connector 5, and supply of power to the Wheatstone bridge circuit and output of load signals are performed via the connector 5.

  On the other hand, an annular metal lid support plate 9 is bonded to the fixing portion 3 on the lower side of the wiring board 11. An annular lid support ring 10 made of metal having a rectangular cross section is bonded to the second member 2d. Then, the metal thin plate annular second lid body 4b having flexibility is bonded or welded so as to cover the lid body support plate 9 and the lid body support ring 10, so that the fixing portion 3, the second member 2d, The lid support plate 9 and the lid support ring 10 are fixed.

  Therefore, the lid body 4 is composed of the first lid body 4a and the second lid body 4b, and is arranged so as to sandwich the strain generating portion 6 relative to each other. The second lid 4b is provided at an intermediate position between the second end face 2e and the strain generating portion 6 in the axial direction of the load receiving portion 2 and is provided at an intermediate position between the first end surface 2b and the strain generating portion 6 in the axial direction. Is provided. The lid support plate 9 and the lid support ring 10 are members that support and fix the first lid 4a and the second lid 4b, and the shape and configuration thereof are not limited thereto.

  In addition, the second end surface 2 e facing the first end surface 2 b of the load receiving portion 2 is provided closer to the strain generating portion 6 than the fixed surface 3 a of the fixed portion 3 in contact with the fixed structure 12. Therefore, when an excessive force is applied to the first member 2 a of the load receiving portion 2, the second end surface 2 e of the second member 2 d abuts on the fixed structure 12, and the further strain-generating portion 6 is further removed. It serves as a stopper to prevent deformation.

  And the load receiving part 2 is provided with the channel | path which connects 2 m of side peripheral surfaces 2m of the load receiving part 2 protruded from the 1st cover body 4a, and the 2nd end surface 2e protruded from the 2nd cover body 4b. . This passage passes through a passage hole 2h which is a cylindrical hollow portion of the load receiving portion 2, and is recessed by a screw portion provided at a portion extending from the handle portion of the first member 2a and the inner wall surface 2f of the second member 2d. And a passage groove 2g forming a recess provided in the second member 2d. Therefore, the fixed structure 12, the cylindrical inner surface 3b of the fixed portion 3, the second lid 4b, the side peripheral surface 2n protruding from the second lid 4b of the load receiving portion 2 and the second end surface 2e are defined. The space 13 is connected to an external space through this passage. Since airtight seal tape or the like is not wound around the thread portion of the handle of the first member 2a, air flows. In the first embodiment, the passage groove 2g is provided in the second member 2d. However, a concave portion or the like may be provided in the umbrella portion of the first member 2a.

  Therefore, the air in the space 13 defined by being surrounded by the fixed structure 12, the cylindrical inner surface 3b of the fixed portion 3, the second lid 4b, the side peripheral surface 2n, and the second end surface 2e is the load receiving portion. Even when a load is applied to the first end surface 2b of 2 and the strain generating portions 6a and 6b are elastically deformed vertically downward and the load fluctuates thereafter, the responsiveness to the change in the load is obtained because the load is changed immediately. An excellent load transducer can be realized.

  FIG. 5 is an exploded perspective view of a load converter 1 according to the second embodiment of the present invention. The handle portion of the first member 2a of the load receiving portion 2 is provided with a flat so-called D-cut surface 2i that cuts a part of the cylindrical surface to form a recess, and the passage groove 2j that forms the recess has a radius on the umbrella portion. In the direction. In this case, the load receiving portion 2 is configured such that the inner wall surface 2f and the cylindrical surface 2k are fitted by fitting such as an interference fit, and the first member 2a is configured not to rotate under the load.

  According to this structure, the air in the space 13 defined by being surrounded by the fixed structure 12, the cylindrical inner surface 3b of the fixed portion 3, the second lid 4b, the side peripheral surface 2n, and the second end surface 2e is The passage hole 2h, the D-cut surface 2i, and the passage groove 2j forming the passage allow access to and from the external space, thereby realizing a load converter that is excellent in response to changes in load.

  In addition, the load receiving portion 2 has a hollow portion in the handle portion of the first member 2a and is provided with a hole in the radial direction from the side peripheral surface 2m of the umbrella portion. It is possible to deform such as connecting to the hollow portion.

  As mentioned above, although this invention was demonstrated based on preferable embodiment, this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the summary.

  As an application example of the present invention, it can be applied to a load measuring device such as a load cell.

1: Load converter 2: Load receiving portion 2a: First member 2b: First end surface 2c: Passage groove 2d: Second member 2e: Second end surface 2f: Inner wall surface 2g: Passage groove 2h: Passage hole 2i: D cut surface 2j: Passage groove 2k: Cylindrical surface 2m: Side peripheral surface 2n (projecting from the first lid): Side circumferential surface 3 (projecting from the second lid) 3: Fixing portion 3a: Fixed Surface 3b: Cylindrical inner surface 4: Lid 4a: First lid 4b: Second lid 5: Connector 6: Strain 7: Bolt 9: Lid support plate 10 Lid support ring 11: Wiring board 12 : Fixed structure 13: Space G, G1c to G6c, G1t to G6t: Load detection means

Claims (3)

A substantially cylindrical load receiving portion that receives a load at the first end face;
A columnar shape having a hollow portion constituted by an inner peripheral surface of a cylindrical surface, the cylindrical side surface of the load receiving portion and the inner peripheral surface having a predetermined interval so as to surround the load receiving portion in the hollow portion. A fixed part arranged to be,
A strain generating portion that is elastically deformed by a load received by the load receiving portion by connecting the cylindrical side surfaces of the load receiving portion and intermediate portions in the axial direction of the inner peripheral surface of the fixing portion in a thin shape,
A plurality of load detecting means provided in the strain generating portion and detecting a load received by the load receiving portion;
A flexible annular lid that is fixed to the load receiving portion and the fixed portion so as to sandwich the strain generating portion relative to each other and close the strain generating portion between the load receiving portion and the fixed portion. When,
A load transducer comprising:
A first lid provided at an intermediate position between the first end face and the strain-generating portion in the axial direction of the load receiving portion; and the load receiving portion in the axial direction of the load receiving portion. A second lid provided at an intermediate position between the second end surface facing the first end surface and the strain-generating portion,
The load receiving portion includes a passage that connects a side peripheral surface of the load receiving portion protruding from the first lid and the load receiving portion protruding from the second lid. Load transducer. The load receiving portion includes an umbrella portion and a handle portion, a first member having a mushroom shape that contacts the load application object at the umbrella portion, and an outer periphery of the handle portion of the first member. A cylindrical second member engaged with the first member,
The passage of the load receiving portion is configured by a cylindrical hollow portion of the second member and a recess provided on at least one engagement surface of the first member and the second member. The load converter according to claim 1. The concave portion includes a portion in which the umbrella portion of the first member and the second member are provided in a radial direction on at least one of the surfaces facing each other in the axial direction. Item 3. The load converter according to Item 2.