LOAD DETECTION APPARATUS

Abstract

A load detection apparatus is provided, which can protect a control circuit portion reliably while a load sensor and the control circuit portion are arranged compactly. The load detection apparatus includes a base plate, a load sensor provided at a first surface of the base plate, a control circuit portion provided at a position on a second surface of the base plate, the position not overlapping the load sensor in a plan view of the base plate, a protection cover covering the control circuit portion, the protection cover includes a base portion covering at least part of a position on the second surface, the position facing the load sensor with the base plate therebetween, a raised portion being continuous to the base portion, and a cover portion being continuous to the raised portion and covering the control circuit portion.

Claims

1. A load detection apparatus comprising: a base plate; a load sensor provided at a first surface of the base plate; a control circuit portion provided at a position on a second surface of the base plate, the position not overlapping the load sensor in a plan view of the base plate; a protection cover covering the control circuit portion; and the protection cover including: a base portion covering at least part of a position on the second surface, the position facing the load sensor with the base plate therebetween, a raised portion being continuous to the base portion, and a cover portion being continuous to the raised portion and covering the control circuit portion.

2. The load detection apparatus according to claim 1, wherein a communication portion for a wire connecting the load sensor and the control circuit portion to each other is provided at the base plate.

3. The load detection apparatus according to claim 1, wherein a fixing portion of the base portion relative to the base plate is provided at at least three points or more in a dispersed manner to form a polygonal shape.

4. The load detection apparatus according to claim 1, wherein the load sensor is formed of a strain generating body and a sensor main body which are divided from each other, a hole portion through which a shaft portion supporting the strain generating body is inserted is formed at the base portion, and a come-off-prevention portion preventing the strain generating body from coming off towards the base portion is provided at an edge portion of the hole portion.

5. The load detection apparatus according to claim 4, wherein the come-off-prevention portion is formed by being bent towards the strain generating body.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a side view of an operation pedal apparatus for a vehicle.

[0022] FIG. 2 is a sectional side view of major portions of the operation pedal apparatus for the vehicle.

[0023] FIG. 3 is a cross-sectional view as viewed from the direction of the arrow, the cross-sectional view which is taken along line III-III of FIG. 1.

[0024] FIG. 4 is a top cross-sectional view of major portions of a load detection apparatus.

[0025] FIG. 5 is a perspective view of the load detection apparatus.

[0026] FIG. 6 is an exploded perspective view of the load detection apparatus.

MODE FOR CARRYING OUT THE INVENTION

[0027] A load detection apparatus of an embodiment will be described hereunder on the basis of the drawings. As described in FIGS. 1 to 3, a load detection apparatus 10 is provided at a pedal 1 used for a brake of a vehicle, for example. The load sensor apparatus 10 includes a load sensor 12 and the load sensor 12 is arranged at an attachment hole 2 provided at the pedal 1. A shaft portion 5 is provided at a rotary connection portion 4 connecting the pedal 1 and a reaction force member 3 to each other in a manner that the pedal 1 and the reaction force member 3 are rotatable relative to each other. The reaction force member 3 is connected to a master cylinder that is not shown. The load sensor 12 detects an operation force transmitted via the shaft portion 5 of the rotary connection portion 4.

[0028] As illustrated in FIGS. 2 to 6, the load detection apparatus 10 includes a base plate 11, the load sensor 12, a control circuit portion 13 and a protection cover 14 covering the control circuit portion 13. The load sensor 12 is arranged at a first surface 31 of the base plate 11. The control circuit portion 13 is provided at a second surface 32 of the base plate 11 so as to be arranged at a position which does not overlap the load sensor 12 in a plan view of the base plate 11.

[0029] As illustrated in FIGS. 2 to 4, the load sensor 12 includes a strain generating body 22 formed in a cylindrical configuration and is accommodated in a hole portion 21a of a sensor main body 21. That is, the load sensor 12 is formed by the strain generating body 22 and the sensor main body 21 which are divided or are separate from each other. The load sensor 12 detects a load applied from the shaft portion 5 inserted in the strain generating body 22 to the strain generating body 22 in a radial direction.

[0030] Because the load sensor 12 is configured in a manner that the load sensor 12 is divided into the strain generating body 22 and the sensor main body 21, in a case where the load sensor 12 is attached to the pedal 1, the strain generating body 22 is in a state of not easily deforming when the pedal 1 is not being operated and the strain generating body 22 is in a state of easily deforming via the sensor main body 21 when the pedal 1 is being operated. That is, by separating the sensor main body 21 and the strain generating body 22 from each other, it is prevented that a load like a noise is transmitted to the strain generating body 22 and detected in a state where the pedal 1 is not being operated.

[0031] A support plate 15 is arranged at an opposite side of the load sensor 2 which is opposite to the base plate 11. By arranging the load sensor 12 and the control circuit portion 13 at the respective sides of the base plate 11 so as to be distributed to the both sides of the base plate 11, the control circuit portion 13 can be arranged to follow an outer portion of the pedal 1 while the load sensor 12 is arranged to be embedded in the pedal 1 serving as an object to be measured, for example. Thus, a degree of freedom in the attachment relative to the pedal 1 is enhanced. In addition, the configuration in which the control circuit portion 13 and the load sensor 12 are arranged at the front side and the rear side of the base plate 11, respectively, is an extremely simple configuration, thereby simplifying the configuration and making a cost reduction possible.

[0032] As the pedal 1 is pressed on, the shaft portion 5 moves relative to the strain generating body 22 and acts on a load receiving portion 25 of the strain generating body 22. The load received by the strain generating body 22 is transmitted to a load transmission portion 26 of the sensor main body 21. At this time, the strain generated at the strain generating body 22 is detected by a strain detection surface 27 provided at the strain generating body 22.

[0033] The load sensor 12 is connected to the control circuit portion 13 via wire 28 formed by, for example. FPC (flexible printed circuit board). The base plate 11 includes a hole portion 16 formed at a portion at which the load sensor 12 is arranged. As illustrated in FIGS. 4 and 6, the hole portion 16 includes a first hole portion 16a corresponding to the strain generating body 22 and a second hole portion 16b extended from the first hole portion 16a to the vicinity of the control circuit portion 13. The second hole portion 16b serves as a communication portion for the wire 28 connecting the load sensor 12 and the control circuit portion 13 to each other.

[0034] The protection cover 14 includes a base portion 41 fixed to the base plate 11, a raised portion 42 which is continuous to the base portion 41, and a cover portion 43 which is continuous to the raised portion 42 and covers the control circuit portion 13. The base portion 41 covers at least part of a position on the second surface 32 of the base plate 11, the position which faces the load sensor 12 with the base plate 11 therebetween. In the embodiment, the base portion 41 is configured to cover the entire load sensor 12. Accordingly, due to the base portion 41, the protection cover 14 is held at the base plate 11 in a stable state, thereby protecting the control circuit portion 13 reliably.

[0035] The base portion 41 includes a hole portion 44 formed at a position corresponding to the first hole portion 16a of the base plate 11. The shaft portion 5 is inserted through the strain generating body 22 via the hole portion 44. An edge portion 45 of the hole portion 44, the edge portion 45 which is at an opposite side to the control circuit portion 13, is formed in a shape which follows an outer circumference of the strain generating body 22. A pair of protruding pieces 46 and 46 is formed at an edge portion of the hole portion 44 in a manner that the protruding pieces 46 and 46 are positioned at the right and left of the shaft portion 5 and the wire 28, respectively. The protruding pieces 46 and 46 are positioned at an inner diameter side relative to the outer circumference of the strain generating body 22. In addition, an edge portion 47 of the hole portion 44, the edge portion 47 which is at the side of the control circuit portion 13, is also positioned at the inner diameter side relative to the outer circumference of the strain generating body 22. The protruding pieces 46, 46 and the edge portion 47 serve as a come-off-prevention portion of the strain generating body 22.

[0036] In a case where the load sensor 12 is configured by the strain generating body 22 and the sensor main body 21 which are separate from each other, the strain generating body 22 needs to be prevented from falling off from an operation member. As described above, in the embodiment, the hole portion 44 through which the shaft portion 5, which is inserted in the strain generating body 22, is inserted is provided at the base portion 41, and the protruding pieces 46 and the edge portion 47 which serve as the come-off-prevention portion that prevents the strain generating body 22 from coming off towards the base portion 41 are provided at the edge portion of the hole portion 44. Accordingly, the coming-off of the strain generating body 22 can be stably prevented and the load sensor 12 including a high detection accuracy can be obtained.

[0037] Each of the protruding pieces 46 and 46 is bent towards the strain generating body 22, thereby forming a bent portion 46a. Thus, the bent portion 46a can push and press the strain generating body 22, thereby holding the strain generating body 22 in a stable manner. In addition, a surface of the bent portion 46a is inclined towards an innermost side of the hole portion 44. Accordingly, the bent portion 46a can be used as a guide portion of the shaft portion 5 when the shaft portion S is being inserted into the hole portion 44, which makes an attachment operation of the load sensor 12 easy.

[0038] The support plate 15 includes a hole portion 51 through which the shaft portion 5 of the strain generating body 22 is inserted. At least part of an edge portion 52 of the hole portion 51 is bent towards the strain generating body 22. The edge portion 52 can be in contact with a lateral surface of the strain generating body 22, and the edge portion 52, together with the above-described bent portion 46a, retains the strain generating body 22 so that the strain generating body 22 is prevented from coining off.

[0039] The base plate 11 includes a hole portion 11a into which a rivet 53 is inserted. The base plate 11, the sensor main body 21 of the load sensor 12 and the support plate 15 are fastened in a state where the rivet 53 is inserted through hole portions provided at the respective members. The base plate 11 and the base portion 41 of the protection cover 14 are, for example, spot-welded at a fixing portion 48. The fixing portion 48 includes three points around the hole portion 44 which are arranged in a dispersed manner to form a triangular shape. The fastening method of the base plate 11, the load sensor 12 and the support plate 15, and the fastening method of the base plate 11 and the protection cover 14 are not specifically limited, and adhesion and/or screw fastening are applicable. The base portion 41 of the protection cover 14 includes an opening 41a formed at a position corresponding to the rivet 53.

[0040] Because the fixing portions 48 of the base portion 41 are arranged in the dispersed manner to form a polygonal shape including the three points, even if an external force supposedly applies to the cover portion 43 and the base portion 41 is to be away from the base plate 11, the plural fixing portions 48 can reliably inhibit the base portion 41 from coming off. For example, in a case where the external force acts on the cover portion 43 and the base portion 41 is to come off while the raised portion 42 that is continuous to the base portion serves as a fulcrum point, the fixing portion 48 that is the farthest from the raised portion 42 functions effectively because the fixing points are provided in the polygonal configuration. That is, a fixing strength of the fixing portion 48 is associated with a distance from the raised portion 42, and thus a fixing state of the protection cover 14 can be more stabilized by ensuring the distance to be long.

[0041] An attachment piece 17 for a wire harness is provided in a standing condition at a side end portion of the base plate 11. The attachment piece 17 includes a hole portion 17a. The wire harness extended from the control circuit portion 13 is placed at and held by a band member arranged at the hole portion 17a.

[0042] The base plate 11 includes an end portion 18 at the side at which the control circuit portion 13 is arranged and the end portion 18 is bent so that the control circuit portion 13 is restricted by the end portion 18 from moving rearward. The control circuit portion 13 is restricted by the raised portion 42 of the protection cover 14 from moving forward. In addition, the base plate 11 includes a bent portion 19 provided at each of the right and left sides of the control circuit portion 13, and the bent portions 19 hold both right and left sides of the control circuit portion 13.

[0043] [Other embodiment] (1) In the above-described embodiment, the example is shown in which the edge portion including a diameter that is smaller than an outer diameter of the strain generating body 22 is formed at the hole portion 44 of the base portion 41 of the protection cover 14, the edge portion which serves as the come-off-prevention portion of the strain generating body 22. However, the come-off-prevention portion of the strain generating body 22 may be any one position of the edge portion of the hole portion 44, or may be the entire edge portion.

[0044] (2) In the above-described embodiment, the example is shown in which the protruding pieces 46 and 46, which are provided at the edge portion of the hole portion 44 as the come-off-prevention portion of the strain generating body 22, are bent. However, the come-off-prevention portion may be formed to simply protrude to the hole portion 44 instead of being bent.

[0045] (3) In the above-described embodiment, the example is shown in which the communication portion for the wire that connects the load sensor 12 and the control circuit portion 13 to each other is provided at the hole portion 16 for the shaft portion 5 which is formed at the base plate 11. However, the communication portion may be configured by a hole portion formed, separately from the hole portion 16, at the base plate 11.

[0046] (4) In the above-described embodiment, the example is shown in which the fixing portions 48, relative to the base plate 11, of the base portion 41 of the protection cover 14 correspond to the three points. However, the fixing portions 48 may be arranged to form a polygonal shape including at least three points or e at the base portion 41. Accordingly, the fixing portions 48 may be four points or more.

[0047] (5) In the above-described embodiment, the example is shown in which a restriction portion (the end portion 18, the bent portion 19) is provided at the base plate 11 which restricts the control circuit portion 13 from moving towards the back surface side and towards the right and left sides. However, a similar restriction portion may be provided at the cover portion 43 of the protection cover 14.

INDUSTRIAL APPLICABILITY

[0048] This invention is applicable widely to a load detection apparatus provided with a load sensor.

EXPLANATION OF REFERENCE NUMERALS

[0049] 1: operation pedal

[0050] 5: shaft portion

[0051] 10: load detection apparatus

[0052] 11: base plate

[0053] 12: load sensor

[0054] 13: control circuit portion

[0055] 14: protection cover

[0056] 15: support plate

[0057] 16: hole portion

[0058] 16a: first hole portion

[0059] 16b: second hole portion

[0060] 21: sensor main body

[0061] 22: strain generating body

[0062] 28: wire

[0063] 31: first surface of the base plate

[0064] 32: second surface of the base plate

[0065] 41: base portion

[0066] 42: raised portion

[0067] 43: cover portion

[0068] 44: hole portion

[0069] 45: edge portion

[0070] 46: protruding piece (come-off-prevention portion)

[0071] 47: edge portion (come-off-prevention portion)

[0072] 48: fixing portion