JP3424894B2 - Mounting structure of compression type load sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a compression type load sensor that detects a load acting on a member to be measured.

[0002]

2. Description of the Related Art Trucks (vehicles) carrying cargo are
Some vehicles have a function to display how much cargo has been loaded on the vehicle so that the loading capacity can be clearly recognized. This function uses a load sensor that detects the strain of the components that make up the suspension system of the truck, detects the same load by utilizing the characteristics of the component that distorts according to the applied load, and displays the result on a display device, etc. It is something to display.

By the way, a high measurement sensitivity is required to detect such a load. Therefore, recently, a compression type magnetostrictive sensor (compression type load sensor) having high detection sensitivity is used as the load sensor instead of the resistance sensor.

A compression type magnetostrictive sensor is formed by assembling a magnetostrictive element (formed by having a drive coil and a detection coil which are 90 ° in phase) as a sensor element on a plate-shaped magnetostrictive member, and is arranged in the compression direction. The magnetic permeability of the magnetostrictive material that changes when a load is applied is used to generate an output proportional to the load from the detection coil.

Such a magnetostrictive sensor is vulnerable to overload because it detects a load from a minute strain generated in the magnetostrictive member. Therefore, as shown in Japanese Patent Laid-Open No. 53-83776, the magnetostrictive material portions on both sides of the magnetostrictive element are disclosed. In order to suppress the input of overload, an opening is formed for stress distribution.

[0006]

However, such a load sensor has a problem that it is difficult to secure sufficient detection sensitivity when it is a large member to be measured to which a large load is applied, such as a component of a truck suspension device.

That is, in the load sensor, in order to obtain high detection accuracy, the sensor main body is made quite small.
Especially, the magnetostrictive sensor is quite small. However, if the measured member on which the load sensor is installed is a large part,
In order to ensure sufficient detection sensitivity, it is required to attach the member to the surface of the member with a relatively long span.

Therefore, in order to mount the load sensor on this large-sized component, it is required to make the entire sensor body of the load sensor large in size in accordance with the span of the mounting position defined on the member to be measured. .

This will impair the initial detection accuracy of the load sensor. In particular, the magnetostrictive sensor has a significant decrease in detection accuracy, and even if the magnetostrictive sensor can be attached to a large member to be measured, it is difficult to obtain sufficient detection sensitivity.

Moreover, since the load sensor, particularly the magnetostrictive sensor, is a precision component, there is a risk that the manufacturing cost will increase significantly as the size increases. Therefore, it is conceivable to attach the load sensors to the surface of the member to be measured at relatively long intervals by using a holder or the like without changing the size of the sensor body.

However, the capacity for suppressing overload on the sensor body (aperture area of the magnetostrictive sensor) depends on the outer shape of the sensor body, so that the overload increased by the expansion of the span is input to the sensor body, and the load sensor Performance may be impaired.

Therefore, there is a demand for a load sensor mounting structure capable of maintaining detection accuracy even when mounted over a long span. The present invention has been made in view of the above circumstances, and an object thereof is to provide a mounting structure of a compression type load sensor that can exhibit sufficient detection accuracy without being overloaded by mounting in a long span. To provide.

[0013]

In order to achieve the above object, in the load sensor mounting structure according to claim 1, a single sensor holder is used and the size of the sensor main body is not changed, and the measured object is measured. The load sensor has a structure that allows it to be mounted on a member over a long span, and a rigidity lowering part that lowers the rigidity is formed between each body support part that supports both ends of the sensor body and each holder mounting part. A high detection sensitivity is ensured by adopting a structure in which the overload transmitted from the section to the sensor body is absorbed by the deformation of the rigidity lowering section regardless of the size of the sensor body.

In the mounting structure of the load sensor according to the second aspect of the invention, the rigidity between both main body supporting portions for supporting both end portions of the sensor main body is weakened, and the strain is transmitted from other than the main body supporting portion toward the center of the sensor main body. Since the path is broken, the compression strain can be efficiently received by the sensor body, and the detection accuracy of the sensor element can be improved.

In the load sensor mounting structure according to a third aspect of the present invention, a simple structure in which a hole is formed between each main body supporting portion and each mounting portion is used to absorb an overload transmitted from the mounting portion to the sensor main body. Will be done.

In the load sensor mounting structure according to the fourth aspect, the overload in the span direction of the mounting portion is effectively absorbed by the elongated hole formed between each body supporting portion and each mounting portion.
The narrow width portion formed between each elongated hole and each main body support portion effectively absorbs the circumferential overload of the mounting portion. That is,
The overload transmitted from the mounting portion is absorbed in each direction by a dedicated stress-reducing portion suitable for absorbing the overload so as to provide high absorbability.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the first embodiment shown in FIGS. Figure 1 (a)
Indicates a vehicle to which the present invention is applied, for example, a rear biaxial truck, 1 is a chassis frame, 2 is a cab, and 3 is a luggage carrier.

Parts for supporting the front wheels 4 of the truck, for example, the front axle beam 5 of the front suspension device, and parts for supporting the rear wheels 6 of the truck, for example, the walking beam 7 of the rear suspension device, are provided on the upper surfaces of the central portions of the respective parts. , A high-sensitivity compression type load sensor for detecting a load applied to each axle, for example, a compression type magnetostrictive sensor 1
0 is installed.

A mounting structure, which is an essential part of the present invention, is used for mounting each magnetostrictive sensor 10. As the mounting structure of each magnetostrictive sensor 10, the structure shown in FIGS. 2 to 4 is used.

Explaining the same mounting structure, the compression type magnetostrictive sensor 10 can be mounted in a large span by combining a single sensor holder 30 with a sensor main body 20 having a small outer shape as shown in FIG. It has a structure.

Specifically, the sensor body 20 has a thin strip plate-shaped sensor plate 21 (corresponding to a long thin plate body) formed of, for example, a magnetostrictive material (magnetic material such as permalloy).
At the center of the sensor plate 21 in the longitudinal direction, four small holes 22 are provided.
Are formed in the cross direction. A drive coil 23 and a detection coil 24 are wound in a cross shape (90 ° phase) between these small holes 22, and a magnetostrictive element 25 (corresponding to the sensor body) is formed at the center of the sensor body 20 in the longitudinal direction. is there.

That is, the sensor main body 20 has the sensor plate 21.
When a load (load) in the compression direction is applied from both ends of the sensor plate 21, the sensor plate 21 is distorted, and the permeability of the magnetostrictive material changes at that time, so that the magnetostrictive element 25 mounted at the center of the sensor plate 21.
An output proportional to the load is generated from the (detection coil 24) (compression load detection). However, a pair of notches 21a that constrict the sensor plate 21 of the same portion are formed on both sides adjacent to the magnetostrictive element 25,
The strain generated between both ends of the sensor plate 21 is transmitted to the central portion of the central magnetostrictive element 25 while being converged.

As shown in FIG. 4, the sensor holder 30 has an installation span of a pair of sensor brackets 31, which are installed side by side on the upper surface of a large member to be measured (front axle beam 5, walking beam 7), for example. A strip plate 30a having an equivalent length is used.

However, in each sensor bracket 31, for example, one side wall is fixed to the member to be measured and the other side wall is L-shaped extending in the direction upright from the surface of the member to be measured, and the bolt insertion hole 32 is formed in the other side wall. To form this bolt insertion hole 3
A structure in which a nut 33 is attached to the outlet end of 2 is used (shown in FIG. 3).

A pair of annular mounting seats 34 (corresponding to mounting portions) are formed at both ends of the strip plate 30a corresponding to the bolt insertion holes 32 of each sensor holder 30, for example. At the center of the mounting seat 34, the bolt insertion hole 3
A through hole 34a having a diameter corresponding to 2 is formed.

A frame, for example, a rectangular frame 35 having thin side portions is formed at the center of the strip plate 31 in the longitudinal direction. In addition, a pair of main body supporting portions, for example, a pair of sensors facing the longitudinal direction of the strip-shaped plate 31 are provided on one side surface portion (corresponding to a portion closer to the inner side than the mounting seat) of the strip-shaped plate 31 that sandwiches the rectangular frame 35. A mounting groove 37 (corresponding to the main body supporting portion) is formed.

Each sensor mounting groove 37 is formed in a shape that conforms to the outer shape of the sensor main body 20, and each end facing the center is opened in the opening 35a of the rectangular frame 35. Both ends of the sensor body 20 are fitted into the sensor mounting grooves 37, respectively.

Further, each end of the sensor body 20 is fixed to each sensor mounting groove 37 so as not to be influenced by distortion, for example, by laser welding, so that the detection sensitivity of the sensor body 20 is not impaired. It is attached (supported) to the sensor holder 30.

The rectangular frame 35 is sized to accommodate the central portion of the sensor body 20 while being exposed to the opening 35a (outside), and the sensor mounting groove 37 of the sensor holder 30 in which the magnetostrictive element 25 is accommodated. The partial rigidity therebetween is weakened, and further, the transmission path of the strain from the portion other than the sensor mounting groove 37 toward the magnetostrictive element 25 is cut off, so that only the strain in the compression direction input from each mounting seat 34 is input to the magnetostrictive element 25. Is done. That is, the rectangular frame 35 has a narrowed portion 35 b at the base portion connected to the sensor body 20.
Is formed, the compressive strain is received by the sensor body 20, and the rectangular frame 35 has a structure that receives almost no load.

Further, in the strip-shaped plate 30a, a rigidity lowering portion is provided in a portion between each mounting seat 34 and each sensor mounting groove 37 (corresponding to a portion between each main body supporting portion and each mounting portion of the holder). As a hole, for example, a pair of elongated holes 38 extending to a point equivalent to the rectangular frame 35 in the width direction (direction intersecting the strain transmission path) of the strip plate 30a around the sensor mounting groove 37 is formed. .

Due to these holes 38, the sensor holder 30
Among these, particularly, the rigidity of the portion between each mounting seat 34 and each sensor mounting groove 37 is locally reduced to impair the detection accuracy of the magnetostrictive element 25 from each mounting seat 34, for example, at the time of mounting. Even if such an overload is input, the hole 38 is deformed so that the overload is absorbed and is not transmitted to the magnetostrictive element 25.

As shown in FIG. 5, the mounting seats 34 are fastened to the sensor brackets 31 by the bolts 39, respectively, so that the small magnetostrictive sensor 10 can be attached to a large member to be measured. It is installed. In particular,
The magnetostrictive sensor 10 is attached to the front axle beam 5, the walking beam 7, etc. with a long span required by, for example, screwing the bolts 39 from the mounting seats 37 into the bolt insertion holes 32, respectively.

Thus, the magnetostrictive sensor 10 mounted in this manner has a relatively long span and is large in size to be measured (front axle beam 5, walking beam 7).
Etc., it is easy to input an overload to the magnetostrictive element 25 from each mounting seat 35 through the magnetostrictive material due to, for example, component tolerances, installation site tolerances (variation in both).

In particular, in the magnetostrictive sensor 10, when a load in the compression direction is applied from both ends of the sensor plate 21 due to loading of cargo, the magnetic permeability of the magnetostrictive material of the magnetostrictive element 25 changes and the load from the detection coil 24 is applied. Since it is a structure that generates an output proportional to, it is vulnerable to overload.

Here, according to the present invention, since the hole 38 having a reduced rigidity is formed in the holder portion between each mounting seat 35 and the magnetostrictive element 25, the above-mentioned overload is caused by the hole. It is absorbed by the deformation of 38, specifically, the deformation of the hole 38 as shown by the chain double-dashed line in FIG. The direction of overload is shown in FIG.

As a result, the magnetostrictive sensor 10 is not affected by overload, and the high detection sensitivity required for detecting the cargo load is exhibited. Moreover, since the holes 38 do not depend on the size of the sensor body 20, it is possible to secure a capacity sufficient to absorb an expected overload, and to efficiently absorb an overload of any size. it can.

As a result, the magnetostrictive sensor 10 can exhibit sufficient detection accuracy irrespective of the overload caused by mounting in a long span. Moreover, since it is not necessary to unnecessarily increase the size of the sensor body 25, there is no significant increase in cost and reduction in detection sensitivity.

Moreover, since the structure is such that both ends of the sensor body 20 are supported by the single sensor holder 30, the work of mounting the sensor body 20 is easy and the high assembly accuracy of the sensor body 20 can be easily secured. .

Further, the structure for reducing the rigidity is provided for each mounting seat 3
Since a hole 38 need only be formed between the sensor 4 and the sensor mounting groove 37, a simple structure is sufficient. 6 and 7 show
2 shows a second embodiment of the present invention.

In this embodiment, the structure of the rigidity lowering portion which lowers the rigidity formed between each mounting seat 34 and each sensor mounting groove 37 is changed. Specifically, each mounting seat 34
And the sensor mounting groove 37 and a rectangular frame 35
A pair of elongated holes 40 extending to exceed the width of the sensor mounting groove 37 is formed to locally reduce the rigidity of the same portion. A pair of narrowed narrow portions 41 are formed, and the rigidity is locally reduced so that the same portion can be deformed in a swinging manner (stiffness reduced portion).

With such a structure, the overload in the span direction of the mounting seat 34 is absorbed by the deformation of each elongated hole 40 as shown by the chain double-dashed line in FIG. At the same time, an overload of the mounting seat 34 in the circumferential direction, for example, the input of the tightening torque of the bolt 39 when the mounting seat 34 is tightened is absorbed by the deformation of the narrowed portions 41. . The arrow in FIG. 7 indicates the direction of overload.

This means that the overload transmitted from the mounting seat 34 is effectively absorbed by the dedicated rigidity-reducing portion suitable for absorbing the overload for each direction, so that the higher overload absorption performance is obtained. Therefore, it is expected that a higher detection sensitivity of the sensor body 20 can be secured.

However, in the second embodiment, the structure other than the rigidity lowering portion is the same as that of the first embodiment, and therefore the description thereof is omitted. In the above-described embodiment, the load sensor (magnetostrictive sensor) is installed on the front axle beam and the walking beam, but the invention is not limited to this, and any other component that can detect the loaded load from strain may be installed on another component. Good. Of course, the load sensor may be attached to the member to be measured by using other fastening parts instead of the bolt.

Of course, although the present invention is applied to the structure for detecting the loaded load of the truck, it is needless to say that the present invention may be applied to a structure for mounting the load sensor for other purposes as well as for vehicle mounting.

[0045]

As described above, according to the invention described in claim 1, since the rigidity lowering portion for lowering the rigidity is formed between each main body supporting portion and each mounting portion of the holder, the mounting portion is removed. The overload transmitted to the sensor body can be sufficiently absorbed by the deformation of the rigidity lowering portion regardless of the size of the sensor body. As a result, the load sensor can secure high detection sensitivity, and can exert sufficient detection accuracy without being overloaded due to installation in a long span.

Moreover, since it is not necessary to unnecessarily increase the size of the sensor main body, a large increase in cost and a decrease in detection sensitivity can be avoided. Moreover, since the sensor body can be mounted with a single sensor holder, the work of mounting the sensor body is easy and high assembly accuracy can be secured.

According to the invention described in claim 2, claim 1
In addition to the effect of the invention described in (1), the opening of the sensor element can efficiently transmit the compressive strain to the sensor body, and the detection accuracy of the sensor element can be improved.

According to the invention of claim 3, claim 1
In addition to the effect of the invention described in (1), it is possible to absorb an overload transmitted from the mounting portion to the sensor body with a simple structure such as forming a hole.

According to the invention of claim 4, claim 1
In addition to the effect of the invention described in (1), the overload transmitted from the mounting portion can be absorbed by a dedicated stress reducing portion suitable for absorbing the overload for each direction such as the span direction of the mounting portion and the circumferential direction of the mounting portion. , Can bring high absorbency.

[Brief description of drawings]

FIG. 1 is a diagram showing a truck (vehicle) to which a compression type load sensor mounting structure according to a first embodiment of the present invention is applied, together with an installation state of a compression type load sensor.

FIG. 2 is an enlarged perspective view showing a state in which a compression type load sensor is attached to a member to be measured.

FIG. 3 is a perspective view for explaining a mounting structure of the compression type load sensor.

FIG. 4 is an exploded perspective view for explaining the structure of the compression type load sensor.

FIG. 5 is a front view for explaining absorption of an overload applied when the compression type load sensor is attached.

FIG. 6 is a perspective view for explaining the structure of the compression type load sensor according to the second embodiment.

FIG. 7 is a front view for explaining absorption of an overload applied when the compression type load sensor is attached.

[Explanation of symbols]

5, 7 ... Front axle beam, walking beam (member to be measured) 10 ... Magnetostrictive sensor (load sensor) 20 ... Sensor main body 21 ... Sensor plate (long thin plate-like body) 25 ... Magnetostrictive element (sensor element) 30 ... Sensor holder 37 ... Sensor mounting groove (a pair of main body supporting parts) 38 ... Void (rigidity lowering part) 40, 41 ... Long hole, narrow width part (rigidity lowering part).

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Komei Hayashida 4-21-1, Shimomaruko, Ota-ku, Tokyo Sanryo Engineering Co., Ltd. (56) Reference JP-A-8-254456 (JP, A) Kai 53-83776 (JP, A) Actual Kaihei 6-69758 (JP, U) Patent 3341623 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01G 19/12 G01L 1 / 00 G01L 1/12 B60P 5/00 G01G 23/06 G01L 1/26

Claims (4)

(57) [Claims] 1. A sensor body for mounting a sensor element in the central portion of a long and thin plate-like body for detecting a compressive load input from the longitudinal direction, and mounting portions at both ends, which are located inward of each mounting portion. There is a pair of main body supporting portions that respectively support both ends of the sensor main body, and a rigidity lowering portion that lowers the rigidity of the same portion is provided between each main body supporting portion and each mounting portion. And a single sensor holder formed in a plate shape, wherein each mounting portion of the sensor holder on which the sensor body is mounted is fixed to a member to be measured. . 2. The compression unit according to claim 1, wherein an opening for exposing the central portion of the sensor main body to the outside and accommodating the central portion of the sensor main body is formed between both main body support portions of the sensor holder. Mounting structure for mold load sensor. 3. The mounting of a compression type load sensor according to claim 1, wherein the rigidity lowering portion is composed of a hole formed between each main body supporting portion and each mounting portion. Construction. 4. The rigidity decreasing portion is an elongated hole formed between each body supporting portion and each mounting portion and extending along each body supporting portion and each mounting portion. And a narrow width portion narrower than each main body support portion, which is formed between each of the elongated holes and each of the main body support portions, respectively. Load sensor mounting structure.