JP2010271146A - Laden weight detection device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laden weight detection device for a vehicle reducing the weighing error of the laden weight, even when the center of gravity of loaded articles is moved, while reducing the mounting number of load cells for detecting the laden weight. <P>SOLUTION: A plurality of packing box support points are provided on a vehicle body, and load cells are incorporated into a half of the plurality of packing box support points; and the position of each packing box support point and each packing box support point into which the load cell is incorporated are set, based on the moving range of the gravity center of the loaded articles. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a vehicle loading weight detection device, and more particularly, to a vehicle such as a tank lorry, a water supply / watering vehicle, a vacuum car, and a garbage collection vehicle, in particular, a load contained in a cargo box such as a tank or a garbage collection box. Even if the center of gravity moves, the weighing error of the detected load weight is reduced.

  2. Description of the Related Art Conventionally, a stationary vehicle weighing scale (track scale) is known as a device for measuring the weight of a load loaded on a vehicle such as a tank truck, a vacuum car, or a garbage truck. However, a truck scale is a large-scale device, which requires equipment costs and requires a large installation space, and often cannot be installed in a small distribution warehouse or distribution center. For this reason, it is not possible to measure at each collection place of the patrol destination, and it is necessary to go to a specific place where the vehicle weighing scale is installed, resulting in a problem of time loss and cost.

Therefore, a load weight detection device mounted on a vehicle is provided.
In vehicles such as the garbage truck, vacuum car, and liquid transport tank truck, the center of gravity of the load contained in the cargo box moves, so when measuring the weight of the load with the load weight detection device mounted on the vehicle. Measurement error is likely to occur.
For example, in the garbage collection vehicle 100 shown in FIGS. 15A and 15B, a dust storage box 101 is provided at the center of the vehicle, and dust is forcibly packed in the dust storage box behind the dust storage box 101. A garbage throwing box 102 equipped with a rotary or compression loading device is provided. The collected dust is opened by the operator, opens the dust input box 102, is carried into the input port, and is forcibly pushed into the dust container box 101. Therefore, when loading dust from the empty state of the dust container 101, the center of gravity G of the dust 105 in the dust container 101 is initially at the rear and moves forward sequentially. The container 101 moves to approximately the center.

  In the tank lorry shown in FIGS. 16A, 16B, and 16C, the tank 110 has a substantially elliptical or circular cylinder in cross section, and the longitudinal axis is arranged along the traveling direction of the vehicle. 110 is installed. In addition, many tanks are installed with a slight inclination to the rear to facilitate liquid discharge from the bottom of the tank. In such a tank, when the filling rate of the liquid in the tank 110 is small, the center of gravity G of the liquid Q in the tank 110 is behind the tank 110 although the deviation in the horizontal direction is small. Move to near the center.

The following proposals have been made as load weight detection devices mounted on the garbage trucks, vacuum cars, tank trucks and the like.
For example, Japanese Patent Laid-Open No. 59-155722 (Patent Document 1) proposes a method of detecting the weight of a load by attaching a strain gauge to the side surface of a differential gear case of a vehicle.
In this method, since the load is applied unevenly to the front and rear axles, in order to perform accurate measurement, it is necessary to measure by attaching strain gauges to all axles. In this case, since the distortion of the vehicle body structure is directly detected, each output sensitivity varies depending on the strain detection position, and if there is a shift of the center of gravity of the load, accurate weighing becomes difficult and it takes a lot of time to adjust the output sensitivity. There is. Further, it cannot be said that protection against strain gauges or compensation for changes in output with respect to temperature changes is sufficient, and there is a problem in performing stable measurement over a long period of time in a severe use environment.

Japanese Laid-Open Patent Publication No. 10-253432 (Patent Document 2) proposes a method for detecting the weight of a load by incorporating a plurality of magnetostrictive load sensors into a shackle pin of a leaf spring of a vehicle or a shaft hole of a trunnion shaft. Yes.
In this method, since the load sensor is press-fitted into the shaft hole, there is a drawback that output sensitivity varies after the sensor is incorporated into the vehicle due to the influence of variations in the press-fitted state. In order to improve the weighing accuracy, it has been shown that a correction resistor is inserted into each sensor for adjustment, but such adjustment has a problem that takes a lot of time.

In Japanese Patent Laid-Open No. 9-2138 (Patent Document 3), a relative position displacement between a loading platform and an axle supporting the loading platform via a suspension (leaf spring) is detected by a photoelectric tube, and a predetermined amount or more is detected by the weight of the load. There has been proposed an overload prevention device that, when depressed, determines that it is overloaded and displays this.
With this device, the amount of sinking of the loading platform varies greatly depending on the position of the load, and overload judgment is likely to vary due to the effects of tire pressure, sag due to aging of the suspension, etc., and overload is stably detected Difficult to do.

  The present applicant has disclosed that the above-mentioned patent documents 1 to 3 can solve the problems of the above-mentioned Patent Documents 1 and can accurately detect the load weight of the vehicle without being affected by the change in the position of the load, the tire pressure or the suspension state. In Japanese Patent No. 340662 (Patent Document 4) and Japanese Patent Application Laid-Open No. 2007-139511 (Patent Document 5), a weighing box is usually supported by a plurality of load cells on a frame of a vehicle body to detect the weight of the load. A vehicle equipped with a machine is provided.

  The devices proposed in Patent Documents 4 and 5 are suitable for accurately measuring the collection amount of dust at the collection destination and the amount of liquid supplied by the liquid transport tank lorry, but are expensive load detection. Since the number of load cells for use increases and an overload detection device only for the purpose of stably detecting an overload state becomes expensive, there is room for improvement.

JP 59-155722 A JP-A-10-253432 JP-A-9-2138 Japanese Patent Laid-Open No. 2002-340662 JP 2007-139511 A

  The present invention has been made in view of the above-described problems, and in vehicles equipped with a cargo box such as a garbage truck, a vacuum car, a tank truck, a truck, etc., even if there is a movement of the center of gravity of the load to be stored in the cargo box, To provide a load weight detection device that can easily measure overloading conditions with a simple configuration, accurately detect overloading conditions, and does not require much time for installation and adjustment, and therefore can detect economical overloading. It is an issue.

  In order to solve the above problems, the present invention provides a plurality of cargo box support points on the vehicle body, and incorporates a load cell in half of the plurality of cargo box support points. There is provided a vehicular loading weight detection device in which a loading box support point to be incorporated is set based on a moving range of a center of gravity of a load.

  As described above, in the present invention, the load cell is only incorporated into half of the load box support points, that is, when the load box support points are four, the load cells are only incorporated into the two load box support points. Therefore, even if the center of gravity of the load contained in the packing box moves, the weight of the load can be detected with a small measurement error, the number of expensive load cells can be reduced, and the load cell can be installed and adjusted without much trouble. I do not take it.

A conventionally well-known mechanism can be adopted as a specific mechanism of the cargo box support member constituting the cargo box support point provided on the vehicle body frame, and the mechanism of the cargo box support member is not limited. Also, the load cell can be any of various known load cells and is not limited. For example, it is preferable to incorporate the thin plate-like load cell or pin type load cell presented in Japanese Patent Application Laid-Open No. 2007-139511 and Japanese Patent Application Laid-Open No. 2004-69323 of the above-mentioned Patent Document 5 relating to the application of the present applicant into the support portion of the packing box. Other existing compression type load cells can also be used.
Specifically, a thin plate-shaped load cell or a pin type load cell is fixed to the upper surface of the body frame of the load box support point and fixed to the lower frame of the load box and attached to the load box support point. A load receiving bracket is fixedly mounted between the upper surface of the vehicle body frame and the lower frame of the cargo box at the cargo box support point where the load cell is not incorporated.
The load box support point that incorporates the load cell and the load box support point that does not incorporate the load cell have the same contact area to be fixed to the lower frame of the load box and hold the lower frame of the load box at the same height. Yes.

As described above, the type of load cell is not limited, but the strain gauge of each load cell is connected so as to form a Wheatstone bridge circuit, and the resistance value is variable before the circuit that sums the strain gauge outputs in parallel. It is preferable that a circuit for adjustment is provided.
That is, when a plurality of load cells are incorporated and weighed, the output sensitivity of each load cell is different due to an installation error of a mounting bracket or a fixing method of each load cell, and an offset error occurs. In the case of a vehicle, this error is likely to occur due to the deformation of the chassis.
On the other hand, with the above configuration, by adjusting the difference in output sensitivity of each load cell with a variable resistor, the deviation error in which the output varies depending on the load loading position is reduced, and the output corresponding to the load is detected. Therefore, highly accurate weighing is possible.

  Furthermore, it is preferable to provide a device that displays the weight of the load detected by the load cell as a ratio with respect to a preset maximum load amount or issues an overload warning.

The position of the load box support point and the position of the load box support point into which the load cell is incorporated are set according to the shape of the load box, the size of the load box, and the like.
In any case, the vehicle body extends in the front-rear direction and is positioned so that the cargo box support point is located on the vehicle body that is symmetrical with respect to the central axis between a pair of left and right vehicle body frames arranged in parallel to the left and right. It arrange | positions on a flame | frame and supports the packing box at these packing box support points.
In the present invention, as described above, the load cells are incorporated in half of the load box support points with respect to the total number of the load box support points.
Since the cargo box support points provided on the vehicle body frame are provided symmetrically on the left and right vehicle body frames, the total number of the cargo box support points is an even number, and thus the half of the total cargo box support points is an integer.
Specifically, there are the following three modes.

In the first aspect, the vehicle body frame extending in the front-rear direction is arranged in parallel to the left and right, and the load is loaded at four or more points on the vehicle body frame that are symmetrical with respect to the central axis between the pair of left and right vehicle body frames. Box support points are provided, and the packing box is supported by these packing box support points,
Load cells are installed in parallel to the front and rear direction at the load box support points which are half of the load box support points and the load box support points on one of the pair of left and right vehicle body frames. The weight of the load to be loaded is detected.

Specifically, when the packing box is small, two left and right vehicle body frames are provided, and a total of four packing box support points are provided. When the packing box is long in the vehicle direction, each of the left and right vehicle body frames has three or more points. A total of 6 or more packing box support points are provided.
In this case, a load cell is incorporated in the front and rear of the load box support point which is half of all the load box support points and on one of the left and right body frame, and is loaded on the load box by the load cell. The weight of the load to be detected is detected.
In other words, if there are two cargo box support points on the left and right body frames, and there are a total of four cargo box support points, load cells are installed at the two cargo box support points on either the left or right body frame. It is out. When the vehicle has a long vehicle length and is supported at 6 points by 3 points on each of the left and right sides, the load cell is incorporated at either one of the left and right support points.

In the second aspect, the vehicle body frames extending in the front-rear direction are arranged in parallel in the left-right direction, and the four points on the vehicle body frame correspond to the four vertexes of a rectangle that is symmetrical with respect to the central axis between the pair of left and right vehicle body frames. The cargo box support points are provided on the vehicle body frame so that the intersection of the two diagonal lines connecting the four vertices is near the horizontal plane center of gravity projection of the maximum load capacity of the load. Set,
Load cells are installed diagonally at two load box support points, which are the vertices of one of the two diagonal lines connecting the four load box support points, and loaded on the load box with the load cell The weight of the load to be detected is detected.
Specifically, load cells are incorporated at the rear support point of the right vehicle body frame and the front support point of the left vehicle body frame, or conversely at the rear support point of the left vehicle body frame and the front support point of the right vehicle body frame.

In the third aspect, the vehicle body frame extending in the front-rear direction is arranged in parallel in the left-right direction, and the vehicle body frame corresponding to the four vertices of an isosceles trapezoid that is symmetrical with respect to the central axis between the pair of left and right vehicle body frames. The cargo box support points are provided at four points, and the points at which the intersections of two diagonal lines connecting the four vertices are folded back at half the height of the isosceles trapezoid are the maximum load capacity of the load Set on the vehicle body frame so that it is near the horizontal plane center of gravity projection point of
Load cells are installed diagonally at two load box support points, which are the vertices of one of the two diagonal lines connecting the four load box support points, and loaded on the load box with the load cells Specifically, it is configured to detect the weight of the loaded object. Specifically, as in the second aspect, the rear support point of the right vehicle body frame and the front support point of the left vehicle body frame, or conversely, the left vehicle body frame Load cells are incorporated at the rear support point and the front support point of the right body frame.

  The relationship between the position of the above-mentioned load box support point and the position of the load box support point into which the load cell is incorporated and the load weighing error will be described below based on the dynamic principle. The result also shows that there is a load (center of gravity) position range of the load with small weighing error.

As shown in FIG. 1, when mounting a rectangular box with a horizontal section, the left and right body frames F1 and F2 are respectively provided with cargo box support points R1 and R2 at the front and cargo box support points R3 and R4 at the rear. It is arranged.
In the first aspect, load cells are incorporated into the cargo box support points R1 and R3 of the vehicle body frame F1 of either the left or right vehicle body frame F1, F2 among the cargo box support points R1 to R4.
In the second aspect, in FIG. 1, load cells are incorporated in the rear side packing box support point R3 of the frame F1 and the front side packing box support point R2 of the frame F2.

  The principle that the measurement error can be reduced even when the center of gravity of the load in the packing box moves with the load cells A and B incorporated in the packing box support points R1 and R3 of the first aspect will be described.

When the origin of the XY coordinates is taken at the center of the horizontally placed rectangular flat plate shown in FIG. 1 and the flat plate is supported at the four corner positions (2a × 2b), the load W is perpendicular to the flat plate at the coordinate position (x, y). Consider the case of loading.
The coordinates (x, y) are projection points on the horizontal plane (XY plane) of the center of gravity of the load. When the weight of the flat plate is excluded and the drag of each support point is R1, R2, R3, R4,
R1 + R3 = (by) / 2b * W = (1-y / b) * W / 2
R1 + R2 = (ax) / 2a * W = (1-x / a) * W / 2
R1 / R3 = (ax) / (a + x)
R1 / R2 = (by) / (b + y)
... (Formula 1-1)
When R1 and R4 are deleted from the above equation (1-1) and R2 and R3 are obtained, R2 = (ax) (b + y) / 4ab × W
R3 = (a + x) (by) / 4ab × W
Therefore, the following formula (1-2) is obtained.
R2 + R3 = {(ax) (b + y) + (a + x) (by)} / 4ab × W
= {(1-x / a) (1 + y / b) + (1 + x / a) (1-y / b} * W / 4
... (Formula 1-2)

When detecting the load by placing a load cell in parallel with the packing box support points R1 and R3 on the same body frame,
From (Formula 1-1),
When y = 0, R1 + R3 = W / 2, which is constant on the X axis.
At load positions other than y = 0, R1 + R3 ≠ W / 2, and the deviation from W / 2 is a weighing error.
From (Equation 1-1), the weighing error becomes the following equation (Equation 1-3).
Measurement error = (R1 + R3) / (W / 2) −1 = −y / b (Formula 1-3)

In the case of detecting the load by diagonally arranging the load cells of the box support points R2 and R3 of the left and right body frames of the second aspect,
From (Formula 1-2) above,
When y = 0, R2 + R3 = W / 2, which is constant on the X axis.
Further, when x = 0, R2 + R3 = W / 2, which is constant on the Y axis.
At load positions other than y = 0 and x = 0, R2 + R3 ≠ W / 2 and a deviation from W / 2 occurs.
Further, when the detection force is different from W / 2 due to the bias of the load position, a measurement error occurs.
From the above (Equation 1-2), the weighing error becomes the following equation (Equation 1-4).
Weighing error = (R2 + R3) / (W / 2) -1
= {(1-x / a) (1 + y / b) + (1 + x / a) (1-y / b)} / 2-1 (Formula 1-4)
It should be noted that the above relational expression holds even when the horizontal cross section of the packing box is square and a = b.

A case where the horizontal section of the third aspect is an isosceles trapezoidal packing box will be described with reference to FIG.
As shown in FIG. 2, the case where it supports with the four vertices of the isosceles trapezoid which makes X-axis symmetrical is considered. The height of the isosceles trapezoid is 2a, the length of the upper base is 2b1, the length of the lower base is 2b2, and the Y axis is taken to be ½ of the height. Similar to the case of the rectangular four-point support shown in FIG.
R1 + R2 = (ax) / 2a × W
R1 / R2 = (b1-y) / (b1 + y)
R3 + R4 = (a + x) / 2a × W
R4 / R3 = (b2 + y) / (b2-y) (Formula 2-1)
From the above equation, R1 and R4 are deleted and R2 and R3 are obtained. R2 = (ax) (b1 + y) / 4ab1 × W
R3 = (a + x) (b2-y) / 4ab2 × W
Therefore
R2 + R3 = {(ax) (b1 + y) / ab1 + (a + x) (b2-y) / ab2} × W / 4
= {(1-x / a) (1 + y / b1) + (1 + x / a) (1-y / b2)} × W / 4
... (Formula 2-2)

これより、ｘ＝（ｂ２−ｂ１）ａ／（ｂ１＋ｂ２）を得る。
ＸＹ座標で（ｘ，０）を点Ｃ’とすると、
点Ｃ’を通りＹ軸に平行な直線（Ｙ’軸）上では、式（２−２）より、
Ｒ２＋Ｒ３＝Ｗ／２（一定）となる。
従って長方形４点支持の場合と異なり、Ｙ軸（ｘ＝０）ではなく、
ｘ＝（ｂ２−ｂ１）ａ／（ｂ１＋ｂ２）に移動したＹ’軸上で、
Ｒ２＋Ｒ３＝Ｗ／２（一定）となる。
また、この点Ｃ’は 等脚台形の対角線の交点ＣをＹ軸に関して折り返した点として求まることは図２の幾何学（三角形の相似）から証明できる。
また、荷重位置の偏りによる下式より求められる計量誤差（式２−３）は前記（式１−４）と同様、以下の式となる。
計量誤差＝（Ｒ２＋Ｒ３）／（Ｗ／２）−１
＝｛(１−ｘ／ａ)(１＋ｙ／ｂ１)＋(１＋ｘ／ａ)(１−ｙ／ｂ２)｝／２−１ …（式２−３） When a load cell is disposed at the packing box support points R2 and R3 and the load is detected, from (Equation 2-2), when y = 0, R2 + R3 = W / 2, which is constant on the X axis.
Also, the right side of (Equation 2-2) is a function of x and y. Similarly to the case of supporting four rectangular points, if there is x where R2 + R3 does not change with respect to the change of y, (R2 + R3) about y The following partial derivatives:

Thus, x = (b2−b1) a / (b1 + b2) is obtained.
If (x, 0) is the point C ′ in the XY coordinates,
On the straight line passing through the point C ′ and parallel to the Y axis (Y ′ axis), from the equation (2-2),
R2 + R3 = W / 2 (constant).
Therefore, unlike the case of rectangular four-point support, not the Y axis (x = 0),
On the Y ′ axis moved to x = (b2−b1) a / (b1 + b2),
R2 + R3 = W / 2 (constant).
Further, it can be proved from the geometry (similarity of triangles) in FIG. 2 that the point C ′ is obtained as a point where the intersection C of the diagonal line of the isosceles trapezoid is turned with respect to the Y axis.
Moreover, the measurement error (Formula 2-3) calculated | required from the following Formula by the bias | inclination of a load position becomes the following formula | equation like the said (Formula 1-4).
Weighing error = (R2 + R3) / (W / 2) -1
= {(1-x / a) (1 + y / b1) + (1 + x / a) (1-y / b2)} / 2-1 (Formula 2-3)

The relationship between the load position and the weighing error is shown in the graphs of FIGS.
The graphs of FIGS. 3 to 5 show the weighing error due to the load position obtained from (Equation 1-3), (Equation 1-4), and (Equation 2-3). The load position where the weighing error is ± 2% and ± 4%. The range is illustrated.
In the graph, a load box support point incorporating a load cell is indicated by a circle, and a load box support point not incorporating a load cell is indicated by a triangle.

FIG. 3 shows the case of the first aspect, in which the load cell is arranged in parallel in the front-rear direction at two points on the same body frame.
In FIG. 3, the measurement error is zero on the X axis, and the measurement error can be reduced by applying to a vehicle in which the horizontal plane center-of-gravity projection point of the load is considered to move along the X axis.

FIG. 4 shows the case of the second aspect, in which the load cell is disposed at diagonal positions on the left and right body frames.
In FIG. 4, the weighing error is zero on the X axis and the Y axis, and the support position of the packing box is set so that the horizontal plane center of gravity projection point of the maximum loading amount coincides with the diagonal intersection C (that is, the origin of the XY coordinates). If determined, the weighing error near the maximum load can be reduced.

FIG. 5 shows the case of the third aspect, in which the four apexes of the isosceles trapezoid are used as load box support points, and the load cells are arranged at diagonal positions on the left and right body frames.
In the figure, b1 / b2 = 0.6.
In FIG. 5, the measurement error is zero on the X-axis and the Y′-axis passing through C ′, and C ′ is a point obtained by turning back the intersection C of the diagonal line on the Y-axis. If the support position of the packing box is determined so that the horizontal plane center-of-gravity projection point of the maximum load capacity coincides with C ′, the weighing error near the maximum load capacity can be reduced.

As described above, the present invention has a configuration in which the load cell is incorporated into half of the load box support points provided in the body frame extending in the pair of left and right front and rear directions. Even if there is a shift in the center of gravity of the load, the weighing error is reduced, the overloading condition is detected accurately, and installation and adjustment are not time-consuming. An overload detection device can be provided.
In addition, it is relatively easy to determine the support position in consideration of the position of the center of gravity of the load while avoiding interference with the fuel tank, battery, and other devices attached to the vehicle body.

It is drawing explaining the dynamic principle which can detect without a measurement error by the load cell in the load box support point which incorporates the load box support point and load cell of the loading weight detection apparatus of this invention. It is drawing explaining the dynamic principle which can detect without a measurement error by the load cell in the load box support point which incorporates the load box support point and load cell of the other loading weight detection apparatus of this invention. It is a graph which shows the relationship between a load position and a measurement error. It is a graph which shows the relationship between the load position and the measurement error which changed the position where a load cell is assembled. It is a graph which shows the relationship between the load position and the measurement error which changed the position where a load cell is assembled into another position. A first embodiment is shown, (A) is a schematic front view, and (B) is a schematic plan view. (A) is a perspective view which shows the load box support point incorporating the load cell, (B) is a perspective view which shows the load box support point which does not incorporate the load cell. It is a schematic perspective view of a thin plate load cell. It is a strain gauge and parallel addition circuit diagram of a load cell. It is the schematic which shows the apparatus connected with the output signal of a load cell. It is a schematic plan view of 2nd Embodiment. It is a schematic plan view of 3rd Embodiment. It is sectional drawing of the vehicle width direction which shows the attachment state of the load cell of 3rd Embodiment. It is a perspective view of the attachment part of the said load cell. (A) (B) is drawing which shows the movement state of the load of a garbage truck. (A)-(C) are drawings which show the movement state of the load of a tank lorry.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a vehicle loading weight detection device of the present invention will be described with reference to the drawings.
6 to 10 show a first embodiment.
In the first embodiment, two loading weight detection devices 10 (10A, 10B) are mounted on the tank lorry 1 in the first mode.

A tank lorry 1 for transporting liquid shown in FIGS. 6A and 6B includes a left vehicle body frame 3 including a pair of left and right vehicle body chassis that extend in the front-rear direction including a part of the rear portion of the driver's seat cabin 2 and are arranged in parallel to the left and right. A right body frame 4 is provided, and the left and right body frames 3 and 4 are connected by a cross member 5.
On the left and right body frames 3, 4 and the cross member 5, a packing box (tank) 6 having a rectangular horizontal section is mounted. A pair of left and right front wheels 7A are attached to the front lower sides of the left and right body frames 3 and 4, and a pair of left and right rear wheels 7B are attached to the lower rear sides.

A central axis (a central axis in the vehicle length direction) between the pair of left and right body frames 3 and 4 is defined as an X axis, and a rectangular vertex is formed on the left and right body frames 3 and 4 that are symmetrical with respect to the X axis. These four points are set as packing box support points R1 to R4, and load cells 10 (10A, 10B) are incorporated in the front and rear packing box support points R1 and R3 on the left body frame 3, respectively.
Instead of attaching the load cell to the left vehicle body frame 3, the load cell may be incorporated at the packing box support points R2 and R4 on the right vehicle body frame 4.

  The positions of the four packing box support points R <b> 1 to R <b> 4 are determined so that the rectangular symmetry axis X coincides with the horizontal plane center of gravity projection point of the liquid load accommodated in the tank 6. The positions of the load box support points R1 to R4 are the estimated positions of the center of gravity in the maximum load capacity of the liquid load. If the load is liquid and has good fluidity and the density is uniform, the volume of the load box 6 and the load box 6 It is determined from the geometric shape such as shape and angle of inclination.

The load cell 10 incorporated in each of the packing box support points R1 and R3 is not limited, but in this embodiment, a thin plate-shaped load cell shown in FIG. Are incorporated between the lower frames 8 of the packing box.
A thin plate-shaped load cell 10 is installed on the left body frame 3, and both ends of the load cell 10 are fastened to the left body frame 3 with fixing bolts 9. The central portion of the load cell 10 is fastened with bolts 12 to the load box lower frame 8 integral with the load box 6 via a load receiving bracket 11.

  At the load box support point of the right vehicle body frame 4 not incorporating the load cell 10, as shown in FIG. 7 (B), the load receiving bracket 11 and the load receiving bracket 11 are fixed to the lower frame 8 fixed to the lower surface of the load box 6. Supporting point fittings 13 having the same joining area are welded to the lower box frame 8, and the lower box frame 8 is kept at the same height as the left side to which the load cell 10 is attached. It is concluded with.

As shown in FIG. 8, the thin plate-shaped load cell 10 (10A, 10B) is provided with a flat load-loading portion 10a in surface contact with the lower surface of the packing box 6 at the center in the length direction and supported on both sides. Strain generating portions 10d and 10e that generate shear strains are provided, each having a through hole between the load applying portion 10a and the supporting portions 10b and 10c. As shown in FIG. 9, four strain gauges (SG1 to SG4, SG1 ′ to SG4 ′) are respectively attached to the inner peripheral surface of the through hole, and one flat load cell 10 has the same configuration as the Wheatstone bridge circuit. The circuit is configured.
In addition, a variable resistor R for reducing the deviation error is provided in the previous stage of the parallel summation.

  The load signal from the load cell 10 having the above configuration is obtained as a voltage signal proportional to the load, and the load signals of the two load cells 10A and 10B are summed in parallel in the connection box 40 connected as shown in FIG. Then, the signal is input to the load cell amplifier 41, and the signal processing device 42 displays the weight value and the ratio with respect to the maximum load capacity. If necessary, an alarm is issued when the maximum load is exceeded.

  In the present embodiment, the load box 6 is supported by the four load box support points R1 to R4, and the load cells 10A and 10B are incorporated into the two load box support points, which are half of the load box support points, to detect the load. However, since the voltage is summed in parallel in the connection box 40, the same voltage signal as that in the case where all the load box support points are used as load cells is input to the load cell amplifier 41.

When the loaded weight 4t is loaded at the position of the intersection point C of the diagonal line connecting the vertexes of the four packing box support points, 1t is loaded on each of the four support points. If the output sensitivity of the load cell with respect to the load is 2 mV / 1t, 2 mV is output from each of the two load cells 10A, 10B to the measurement box. Due to the parallel summation of the voltages in the connection box 40, (2 mV + 2 mV) / 2 = 2 mV is obtained, and 2 mV is input to the load cell amplifier 41.
On the other hand, when load cells are installed at all four load box support points, 2 mV is output from each of the four load cells, and (2 mV + 2 mV + 2 mV + 2 mV) / 4 = 2 mV is obtained by parallel summation of the voltage in the measurement box. As in the case of two load cells, 2 mV is input to the load cell amplifier 41. Therefore, the load cell amplifier 41 has the same gain, and the load display can be easily adjusted.

  Each of the load cells 10A and 10B has an output sensitivity with respect to a load accurately adjusted at the time of manufacture, and is normally suppressed to a variation within 0.1 to 0.2%. Further, the signal processing device 42 after the load cell amplifier 41 can easily adjust the weight display with high accuracy at the inspection stage at the time of manufacture by inputting the expected load cell output voltage. Therefore, after the load cells 10A and 10B are incorporated into the vehicle, the adjustment of the target overload detection device is completed in a short time without connecting individual signal sensitivity by simply connecting the signal lines.

  In the loading weight detection device having the above-described configuration, the liquid loading to be accommodated in the packing box 6 can be achieved by simply placing the load cells 10 at two of the four packing box support points R1 to R4. Even if the center of gravity of the object moves, the measurement error becomes zero from (Equation 1-4), and the measurement error can be made substantially minute. In addition, since it is only necessary to attach the load cells to half of all the packing box support points, the number of load cells can be reduced, and the cost can be reduced. Since the number of load cells is reduced, there is an advantage that maintenance becomes easy.

FIG. 11 shows a second embodiment.
In the second embodiment, the cargo box 6 is supported on the left and right body frames 3 and 4 in the above-described aspect 2 in a vehicle including a garbage collection vehicle.
Also in the second embodiment, two front and rear bodies are arranged on the left and right body frames 3 and 4, respectively, and the cargo box 6 is supported by four cargo box support points R1 to R4 which are rectangular vertices. Among these packing box support points R1 to R4, load cells 10 are respectively incorporated in packing box support points R2 and R3 at diagonal positions.

As described above, when the two load cells 10 (10A, 10B) are diagonally arranged, the four cargo box support points R1 to R4 are, as shown in FIG. 11, four cargo box support points R1. The positions of the packing box support points R1 to R4 are determined so that the intersection C of the rectangular diagonal line surrounded by ~ R4 coincides with the horizontal plane center of gravity projection point of the maximum load of the load.
When the horizontal plane center-of-gravity projection point of the load is on the X-axis or the Y-axis in FIG. 11, the measurement error is zero according to (Expression 1-4).
Note that the estimated position of the center of gravity in the maximum load capacity of the load is relatively large from the geometric shape such as the volume and shape of the packing box (tank) 6 and the inclination angle when the load is liquid and fluid and has a uniform density. Easy to determine. In the case of dust that is not liquid, it is possible to assume the approximate range of the center of gravity of the maximum loading capacity assuming density non-uniformity.

  The configuration in which the load cell 10 is incorporated in the packing box support points R2 and R3 of the second embodiment is the same as that in FIG. 7A of the first embodiment, and the configuration of the packing box support points R1 and R4 in which the load cell is not incorporated is also used. This is the same as in FIG. 7B of the first embodiment.

A third embodiment is shown in FIGS.
The third embodiment is a tank lorry similar to that of the first embodiment, and the packing box 6 is supported on the left and right vehicle body frames 3 and 4 in the mode 3 described above.
Also in the third embodiment, two front and rear bodies are arranged on the left and right body frames 3 and 4, respectively, and the cargo box 6 is supported by four cargo box support points R1 to R4 which are the vertices of an isosceles trapezoid. The load cells 30 (30A, 30B) are incorporated in the load box support points R4 and R1 at diagonal positions among the load box support points R1 to R4. The load cells 30A and 30B are pin type load cells.

As described above, when the two load cells 30 (30A, 30B) are diagonally arranged, the four packing box support points R1 to R4 are the packing box support points R1 to R4 as shown in FIG. The positions of the cargo box support points R1 to R4 are set so that the intersection point C of the diagonals of the enclosed isosceles trapezoid is folded at half the height of the isosceles trapezoid and is near the horizontal plane center of gravity projection of the maximum load capacity Has been decided.
When the horizontal plane center-of-gravity projection point of the load is on the X-axis or Y′-axis of FIG. 12, the measurement error is zero from (Equation 2-3).

Since the cargo box support points R3 and R4 on the rear side of the body frames 3 and 4 are located outward from the body frames 3 and 4, they are attached to the body frames 3 and 4 in the configuration shown in FIGS. ing.
At the cargo box support point R4 at the rear of the vehicle body frame 4, there is a space between the vehicle body side load receiver 33 projecting laterally outward and the two cargo box side load receivers 22A and 22B projecting laterally outward from the cargo box lower frame 8. They are connected by a pin type load cell 30A. The vehicle body side load receiver 33 is connected to the left and right vehicle body frames 3 and 4 by using a connection plate 34, an outer bracket 35 and an inner bracket 36.
On the other hand, a metal fitting 37 is attached to the left body frame 3 at a packing box support point R3 where the load cell 30 is not incorporated. The metal fittings 37 use support pins 38 having the same diameter as the pin type load cell 30A.
Since the connecting plate 34 connecting the left and right body frames 3 and 4 receives a load at a position protruding from the left and right body frames 3 and 4, the left and right body frames 3 and 4 are prevented from being excessively twisted and supported by the pin type load cell 30. It has the role of making it easy to obtain the load load symmetry of the pin 38.
The vehicle body side load receiver 33 may protrude from the lower surfaces of the vehicle body frames 3 and 4 and the cargo box lower frame 8 so that the pin type load cell 30 and the support pin 38 are arranged symmetrically.
The load cell 30B mounted on the load box support point R1 at the front of the vehicle body frame 3 is the same device as the load cell 30A, but is disposed between the upper surface of the vehicle body frame 3 and the lower surface of the load box 6.

  The load cell is not limited to the thin plate load cell or the pin type load cell of the above embodiment, and may be a compression type load cell. Further, the mechanism for fixing the load cell between the vehicle body frame and the cargo box is not limited to the mechanism of the embodiment.

R1-R4 Cargo box support point 3 Left car body frame 4 Right car body frame 6 Cargo box 10 (10A, 10B), 30 (30A, 30B) Load cell

Claims (5)

  A plurality of load box support points are provided on the vehicle body, and a load cell is incorporated in half of the plurality of load box support points, and the position of the load box support point and the load box support point into which the load cell is incorporated are defined as the center of gravity of the load. The vehicle loading weight detection device is set based on the movement range of the vehicle. A body frame extending in the front-rear direction is arranged in parallel in the left-right direction, and a cargo box support point is provided at four or more positions on the body frame that are symmetrical with respect to the central axis between the pair of left and right body frames, These packing box support points support the packing box,
Load cells are installed in parallel to the front and rear direction at the load box support points which are half of the load box support points and the load box support points on one of the pair of left and right vehicle body frames. The vehicle load weight detection apparatus according to claim 1, wherein the load weight detection apparatus is configured to detect a weight of a load to be loaded. A body frame extending in the front-rear direction is disposed in parallel in the left-right direction, and the cargo box support points are arranged at four points on the body frame corresponding to four vertices of a rectangle that is symmetrical with respect to the central axis between the pair of left and right body frames. And these packing box support points are set on the vehicle body frame so that the intersection of the two diagonal lines connecting the four vertices is near the horizontal plane gravity center projection point of the maximum load capacity of the load,
Load cells are installed diagonally at two load box support points, which are the vertices of one of the two diagonal lines connecting the four load box support points, and loaded on the load box with the load cell The vehicle load weight detection device according to claim 1, wherein the load weight detection device is configured to detect a weight of a load to be loaded. A body frame extending in the front-rear direction is arranged in parallel on the left and right, and the cargo box is placed at four points on the body frame corresponding to the four vertices of an isosceles trapezoid that is symmetric with respect to the central axis between the pair of left and right body frames. Supporting points are provided, and these packing box support points are near the horizontal plane center of gravity projection of the maximum load capacity of the load at the intersection of the two diagonal lines connecting the four vertices at half the height of the isosceles trapezoid. Set on the body frame so that
Load cells are installed diagonally at two load box support points, which are the vertices of one of the two diagonal lines connecting the four load box support points, and loaded on the load box with the load cells The vehicle load weight detection device according to claim 1, wherein the load weight detection device is configured to detect a weight of a load to be loaded.   5. The apparatus according to claim 1, further comprising a device that displays a weight of the load detected by the load cell as a ratio to a preset maximum load amount or issues an overload warning. Vehicle load detection device.

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