JP2010276047A - Brake force acquisition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability in a compressive force detecting element of a brake force acquisition device. <P>SOLUTION: In an anchor member 16, the compressive force detecting element 40 is formed as a structure for receiving a load F via a load action part 50 being a rigid body, and is also formed as a structure for receiving the load applied to the load action part 50 by a pair of connecting parts 54 and 56 and the compressive force detecting element 40 existing in the middle of its parts. As a result of it, bending force is hardly applied to the compressive force detecting element 40 by an eccentric load. The durability of the compressive force detecting element 40 can be improved by that extent, and the service life can lengthened. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake force acquisition device that acquires a brake force applied to a wheel by the action of a brake.

Patent Document 1 describes a load detection device that is provided on an anchor of a drum brake and detects a load applied from a brake shoe. A hole is formed inside the anchor, and a part of the wall surrounding the hole is made into a plate-like load acting part that is easily elastically deformed, and a strain sensor is arranged inside the load acting part {part facing the hole (space)}. Is provided. When a load is applied by bringing the brake shoe into contact with the load acting portion of the anchor, the load acting portion is elastically deformed (bent). The amount of elastic deformation is detected by the strain sensor, thereby detecting the load applied to the anchor.
Patent Document 2 describes a pedaling force detection device that detects a pedaling force applied to a brake pedal. The pedaling force detection device is provided around the clevis pin that connects the brake pedal and the operating rod, and detects the pedaling force based on the shear deformation of the detection member caused by the relative movement of the brake pedal with respect to the clevis pin. The detection member generally has a hollow cylindrical shape. One end of the cylindrical portion is connected to a member on the brake pedal side, the other end is connected to a member on the clevis pin side, and the intermediate portion is opposed to the space, and is elastic. Holds deformable. A strain gauge is attached to the outer peripheral surface of the intermediate portion of the detection member, and shear deformation of the detection member is detected by the strain gauge.

JP 2002-67914 A JP 2008-120348 A

  The subject of this invention is suppressing the bending force applied to a sensor main body in a brake force acquisition apparatus.

Means and effects for solving the problem

The brake force acquisition device according to claim 1 is actually applied to the wheel of a brake that is operated by sliding a friction member held by a non-rotating body on a friction surface of a brake rotating body that rotates together with the wheel. A braking force acquisition device for acquiring an applied braking force, provided on a load receiving member that is fixed to the non-rotating body and receives a load by contacting the friction member when the brake is applied, (i) A compressive force detecting element that is gripped by a rigid body and detects a compressive force applied by the load in a direction parallel to the acting direction of the load received by contact with the friction member; and (ii) the compressive force detecting element, A connecting member that is provided on at least one side in a direction intersecting the direction in which the load acts and receives a part of the load.
The brake force acquisition device is provided on a load receiving member that receives a load by contacting the friction member when the brake is applied. The load receiving member is an anchor when the brake is a drum brake, and is a torque receiving member when the brake is a disc brake. Since a predetermined relationship is established between the load received by the load receiving member from the friction member and the braking force applied to the wheel by the action of the brake, the brake is applied based on the load received by the load receiving member from the friction member. You can get power. From this, it can be considered that the brake force acquisition device includes a load detection device that detects a load that the load receiving member receives from the friction member.
The brake force acquisition device includes a compression force detection element and a connecting member. The compressive force detection element is provided in a state of being gripped by a pair of rigid bodies in a direction parallel to the direction in which the load acts, and the pair of rigid bodies are coupled by a coupling member. For example, it is desirable that the compressive force detection element is provided at a substantially central portion of the load receiving member in a direction intersecting with the load acting direction, and the connecting portion is provided near an end portion in the direction.
One of the pair of rigid bodies is a load acting portion that receives a load when the friction member comes into contact therewith. Since the load acting portion is a rigid body, the load acting portion does not bend even if the friction member comes into contact with the load. In the load acting portion, the force applied by the friction member balances the force received by the compression force detecting element and the force received by the connecting member. Further, a predetermined relationship is established between the contraction (compression amount) of the compression force detecting element and the deformation amount (contraction or expansion) of the connecting member. Therefore, based on the compression force detection element, the dimensions of the connecting member (cross-sectional area, Young's modulus, length in the direction in which the load before deformation acts, etc.) and the like and the detection value by the compression force detection element, It is possible to acquire the magnitude of the load received by the.
On the other hand, the friction member abuts on the load acting portion, but if the abutment point (hereinafter referred to as the load acting point) shifts with wear of the friction member, a bending moment is generated. On the other hand, in the brake force acquisition device according to claim 1 of the present application, the compressive force detecting element and the connecting member are gripped by a rigid body in a direction parallel to the acting direction of the load, and the connecting member and the compressive force are detected. Since the elements are provided apart from each other in a direction intersecting with the direction in which the load is applied, it is possible to make it difficult for a bending force to act on the compressive force detecting element, and to improve durability.
When the braking force acquisition device described in this section is compared with the load detection device described in Patent Document 1, in the load detection device described in Patent Document 1, it is assumed that the load acting part is easily elastically deformed, and the load While the load is detected based on the distortion of the action part, in the brake force acquisition device described in this section, the load action part is a rigid body, and the compressive force detection element is received via the load action part. The difference is that the load is acquired based on the compression force. Therefore, in the load detection device described in Patent Document 1, the strain gauge is provided in a state facing the space, that is, in a state where the strain of the load acting portion can be detected, whereas the brake described in this section In the force acquisition device, the compressive force detection element is provided by being gripped by a pair of rigid bodies. Thus, the principle of detecting the load differs between the load detection device described in Patent Document 1 and the brake force acquisition device described in claim 1 of the present application.
The rigid body and the connecting member may be configured by a part of the load receiving member or may be configured by a member different from the load receiving member. When constituted by another member, it is fixedly attached to the load receiving member.
Further, the connecting member may be provided on both sides of the compressive force detecting element in the direction intersecting with the acting direction of the load, or may be provided on either side.
Further, the compressive force detecting element can detect the compressive force using a piezo effect, a piezoresistive effect, or the like.
Further, the brake force acquisition device may be provided on the disc brake or the drum brake.

Patentable invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the set of components constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

(1) A brake that detects a braking force that is actually applied to the wheel, of a brake that is operated by sliding a friction member held by a non-rotating body against a friction surface of a brake rotating body that rotates together with the wheel. A force acquisition device,
It is fixed to the non-rotating body and is provided on a load receiving member that receives a load by contacting the friction member when the brake is applied,
(i) a compressive force detecting element that is gripped by a rigid body in a direction parallel to an acting direction of a load received by contact with the friction member and detects a compressive force applied by the load;
(ii) including a connecting member that is provided on at least one side of the compressive force detecting element in a direction perpendicular to the friction surface of the brake rotating body of the load receiving member and receives a part of the load. Brake force acquisition device.
(2) The connection member is provided on at least one side of the compressive force detection element in a direction perpendicular to a tangential plane of the friction surface of the brake rotating body of the load receiving member. Brake force acquisition device.
(3) The brake force acquisition device according to (2), wherein the connecting members are provided on both sides in a direction orthogonal to a tangential plane of the friction surface of the compression force detecting element.
If the connecting member is provided on both sides of the compressive force detecting element, the load received by the compressive force detecting element can be made smaller than that provided on one side. Further, even if an eccentric load is applied, it is possible to make it difficult for a bending force to act on the compression force detecting element.
The connecting member is provided on at least one side in a direction substantially perpendicular to the tangential plane of the friction surface of the brake rotating body in the load receiving member. The “direction substantially orthogonal to the friction surface of the brake rotating body in the load receiving member” is one of the directions intersecting the load acting direction. When the brake is a drum brake, the “friction surface of the brake rotating body” is the friction surface on the inner peripheral side of the drum, and the “direction perpendicular to the tangential plane of the drum friction surface at the anchor” is, for example, The direction perpendicular to the tangent plane of the drum at the midpoint of the circumferential direction of the anchor, that is, the radial direction. Further, the direction “substantially” orthogonal to the tangential plane of the drum inner peripheral surface may be slightly inclined with respect to the direction orthogonal to the tangential plane (for example, it may be inclined approximately π / 6). This means that it may be tilted depending on the shape of the drum brake, such as the shape of the anchor or the shape of the brake shoe. When the brake is a disc brake, the “friction surface of the brake rotating body” is the friction surface of the rotor, and the “direction perpendicular to the tangential plane of the friction surface (the friction surface and the tangential plane are parallel)” The direction is parallel to the rotational axis of the wheel.
(4) The brake force acquisition device according to any one of (1) to (3), wherein a space is provided between the coupling member and the compression force detection element.
The connecting member is provided at a position separated from the compressive force detecting element.
(5) An interposition member having a Young's modulus smaller than the Young's modulus of the connecting member and smaller than the Young's modulus of the compressive force detecting element is provided between the connecting member and the compressive force detecting element. The brake force acquisition device according to any one of items) to (3).
The Young's modulus of the interposed member is smaller than both the Young's modulus of the connecting member and the Young's modulus of the compressive force detecting element. In other words, the Young's modulus of the connecting member and the Young's modulus of the compressive force detecting element are smaller than the smaller one.
If the Young's modulus is very small, the intervening member can be handled in the same manner as when a space is provided when detecting the load. Moreover, the positioning accuracy of the compressive force detection element can be improved by providing the interposition member.
The Young's modulus of the intervening member should be a value equal to or less than a set value that can be ignored (can be handled in the same way as space) when detecting the load relative to the Young's modulus of the compressive force detecting element and the Young's modulus of the connecting member. Can do.
(6) The compressive force detection element includes (i) a load acting portion that is a portion that receives the load by contact of the friction member of the load receiving member, and (ii) the load in a direction parallel to the acting direction of the load. Any one of items (1) to (5) provided at a portion opposite to the load acting portion and gripped by a rigid body including a nest and an intermediate member elastically deformed by press-fitting of the nest The brake force acquisition device described in 1.
The compressive force detecting element is gripped by a rigid body including an elastic member and a nest and the like, and a load acting portion that is a rigid body. The compressive force detecting element is held in a state where a load is applied (a state where a load is applied). In addition, the press-fitting allowance of the nesting can be designed to a size that can hold the compressive force detecting element satisfactorily.
(7) A direction of the load receiving member that is provided on a side of the compressive force detecting element opposite to the side in which the friction member abuts in the direction of the load, and is parallel to the direction of the load applied to the load receiver. A gripping force adjusting device that holds the compressive force detecting element by applying the force and can adjust the force applied to the compressive force detecting element includes any one of items (1) to (6) The brake force acquisition device described in 1.
In the gripping force adjusting device described in this section, the gripping force (holding force) applied to the compression force detecting element can be adjusted. Thereby, the applied load (set load) can also be adjusted. If the gripping force is increased, the compression force detecting element can be favorably held. However, when the set load increases, the zero point increases, which is undesirable in detecting the compressive force. Therefore, in consideration of these, it is desirable to adjust the gripping force applied to the compression force detecting element to a desired magnitude.
(8) The brake rotating body is a drum that rotates together with the wheel, the load receiving member is an anchor fixed to a backing plate as the non-rotating body, and the friction member is the above-mentioned friction plate of the backing plate. The brake force acquisition device according to any one of items (1) to (7), wherein the brake shoe is a pair of arcuate brake shoes held on both sides of the anchor so as to be relatively movable.

It is front sectional drawing of the drum brake of the brake device with which the brake force acquisition apparatus which is one Example of this invention is included. It is a figure which shows the anchor member of the said drum brake. It is a figure which shows the load detection apparatus contained in the said brake force acquisition apparatus. In the said drum brake, it is a figure which shows the relationship between the load applied to an anchor member, and braking force. It is a figure which shows another load detection apparatus provided in the said drum brake. It is a figure which shows the principal part of the load detection apparatus contained in the brake force acquisition apparatus which is another one Example of this invention. In the said brake force acquisition apparatus, it is a figure which shows the relationship between a set load and the tightening torque of a screw. It is a figure which shows the principal part of the load detection apparatus contained in the brake force acquisition apparatus which is another one Example of this invention. It is a figure which shows the principal part of the load detection apparatus contained in the brake force acquisition apparatus which is another one Example of this invention.

  Hereinafter, a brake device including a brake force acquisition device according to an embodiment of the present invention will be described in detail with reference to the drawings.

The brake device according to the first embodiment includes a drum brake 6. The drum brake 6 includes a backing plate 8 as a non-rotating member attached to a vehicle body (not shown), and a drum 12 having a friction surface 10 on the inner peripheral side and rotating together with a wheel. The pressing mechanism 14 of the electric actuator 13 is fixed to a position separated from the backing plate 8 in one diameter direction, and the anchor member 16 is fixed by two pins 18. In addition, a pair of brake shoes 20a and 20b each having an arcuate shape between the anchor member 16 and the pressing mechanism 14 face the friction surface 10 of the drum 12, and the shoe hold down devices 22a and 22b are used for backing plates. 8 is mounted so as to be movable along the surface.
The through hole provided in the center of the backing plate 8 is for allowing the axle shaft (not shown) to pass therethrough.
In this embodiment, the electric actuator 13 includes an electric motor 24, and the pressing mechanism 14 is operated by the electric motor 24.

Each of the pair of brake shoes 20a, 20b has one end engaged with the pressing mechanism 14 and the other end in contact with the anchor member 16 so that the pair of brake shoes 20a, 20b can be expanded. Further, brake linings 26a and 26b as friction materials are held on the outer peripheral surfaces of the brake shoes 20a and 20b, and the pair of brake linings 26a and 26b are brought into sliding contact with the friction surface 10 of the drum 12. A frictional force is generated between the brake linings 26 a and 26 b and the drum 12.
Further, an adjuster-equipped strut 28 and a return spring 29 are provided between one end portions of the pair of brake shoes 20a and 20b. The strut 28 with adjuster adjusts the gap between the pair of brake linings 26a, 26b and the drum inner peripheral surface 10 according to wear of the brake linings 26a, 26b.
Thus, this drum brake is of the leading and trailing type.

The anchor member 16 is provided with load detection devices 36 and 38. The load detection devices 36 and 38 are provided inside the anchor member 16 and on the outer portions of the two pins 18. The load detection device 36 detects the load received by the anchor member 16 from the brake shoe 20b, and the load detection device 38 detects the load received from the brake shoe 20a. Since the load detectors 36 and 38 have the same structure, the load detector 36 will be described and the description of the load detector 38 will be omitted.
The load detection device 36 is provided at a portion of the anchor member 16 on the side where the brake shoe 20b abuts. As shown in FIGS. 2 and 3, the load detection device 36 includes one compression force detection element 40 gripped in the tangential direction. Including. The tangential direction is a direction parallel to the tangential direction of the drum 12 at the center point A (the midpoint of the pair of pins 18) in the circumferential direction of the anchor member 16, and the radial direction is the center point A of the anchor member 16. Is a direction parallel to a direction orthogonal to the tangential plane of the friction surface 10 of the drum 12 (a direction parallel to the radial direction of the drum 12 at the center point A of the anchor member 16).

As shown in FIG. 2, an element holding hole 42 penetrating in a direction parallel to the rotation axis of the wheel (hereinafter abbreviated as the direction of the rotation axis of the wheel) is formed in a portion outside the pin 18 of the anchor member 16. A nesting press-fit hole 44 is formed in a tangential direction.
The element holding hole 42 is a hole in which the compressive force detecting element 40 is disposed, and is surrounded by a pair of wall portions 50 and 52 opposed in the tangential direction and a pair of wall portions 54 and 56 opposed in the radial direction. ing. The wall portion 50 is a load acting portion where a load is applied when the brake shoe 20b abuts, and the wall portion 52 is an intermediate elastic deformation portion 52 between the wall portion 50 and the telescopic press-fit hole 44. The thickness (the length in the tangential direction) of the load application portion 50 is d ₁ , and the thickness of the intermediate elastic deformation portion 52 is d ₂ . The shape (thickness d _{1 and the} like) of the load acting portion 50 is a shape that can be regarded as a rigid body, that is, a shape that does not bend even when the load F is applied. (Thickness d ₂ etc.) is a shape (plate-like member) that can be elastically deformed in the tangential direction.
The wall portions 54 and 56 are connecting portions 54 and 56 extending in parallel with a tangential direction connecting the load acting portion 50 and the intermediate elastic deformation portion 52.

  The nesting press-fitting hole 44 is a hole into which the nesting 58 is press-fitted, and is surrounded by a pair of wall portions 62 and 52 opposed in the tangential direction and a pair of wall portions 64 and 66 opposed in the radial direction. The wall portion 62 is the anchor main body portion 62 and is thicker than the intermediate elastic deformation portion 52. Therefore, when the insert 58 is press-fitted into the insert press-fitting hole 44, the intermediate elastic deformation portion 52 is elastically deformed. The wall portions 64, 66 are provided continuously with the connecting portions 54, 56, and serve as connecting portions 64, 66 that connect the intermediate elastic deformation portion 52 and the anchor main body 62.

The width of the element holding hole 42 in the tangential direction is w ₁ , and the width of the nesting press-fit hole 44 in the tangential direction is w ₂ . The tangential width of the compressive force detecting element 40 is smaller by Δw ₁ than the width w ₁ of the element holding hole 42, and the width of the insert 58 to be press-fitted into the insert press-fit hole 44 is the tangential width of the insert press-fit hole. The width w _{2 of} 44 is larger by Δw ₂ . Further, the press-fit allowance Δw ₂ of the insert 58 is larger than the gap Δw ₁ of the compression force detecting element 40 (Δw ₂ > Δw ₁ ).
The radial dimension of the element holding hole 42 and the nested press-fit hole 44 are both t ₀ , whereas the radial dimension of the compressive force detecting element 40 and the radial dimension of the nested 58 are both Also, t ₁ is smaller than the dimensions of the element holding hole 42 and the nested press-fitting hole 44 (t ₁ <t ₀ ). Therefore, when the compressive force detecting element 42 is disposed in the element holding hole 42, spaces 70 and 72 are formed between the compressive force detecting element 42 and the connecting portions 54 and 56. Similarly, when the insert 58 is press-fitted into the insert press-fitting hole 44, a space is formed between the connecting portions 64 and 66, and the intermediate elastic deformation portion 52 is elasticized by the press-fitting of the insert 58. It is easy to deform.
Therefore, when the insert 58 is press-fitted into the insert press-fitting hole 44, the intermediate elastic deformation portion 52 is elastically deformed in the tangential direction as shown in FIG. As a result, the compressive force detecting element 40 is gripped by the rigid body 75 such as the intermediate elastic deformation portion 52 (the rigid elastic body 75 is constituted by the intermediate elastic deformation portion 52, the insert 58, and the anchor main body portion 62) and the load acting portion 50. In the tangential direction, the two rigid bodies 50 and 75 are held and fixed.
Further, in the present embodiment, the press-fit allowance Δw ₂ of the insert 58 is set to a size that allows the compressive force detection element 40 to be satisfactorily gripped by design.
Further, the compressive force detecting element 40 is disposed at the center in the radial direction of the element holding hole 42, and is disposed in a posture positioned substantially on the central axis P passing through the center in the radial direction of the anchor member 16. The Therefore, the dimensions of the spaces 70 and 72 in the radial direction are the same.
The compressive force detecting element 40 detects the compressive force using a piezo effect, a piezoresistive effect, or the like.
The load detection device 38 is similarly configured.

  The brake force acquisition device includes a brake ECU 80. The brake ECU 80 mainly includes a computer including an execution unit, a storage unit, an input / output unit, and the like. The input / output unit includes a brake that detects the operation state of the load detection devices 36 and 38 and a brake operation member (not shown). An operation state detection device and the like are connected, and the electric motor 24 is connected via a drive circuit (not shown). The storage unit stores a table representing the relationship between the load F and the braking force represented by the map of FIG.

In the drum brake configured as described above, when the brake action request is detected, the pressing mechanism 14 is operated by driving the electric motor 24. The pair of brake shoes 20a, 20b is expanded and brought into sliding contact with the friction surface 10 of the drum 12, and the drum brake 6 acts. The other ends of the brake shoes 20a and 20b abut against the anchor member 16, and the anchor member 16 receives a load F. Although the load F is detected and the braking force is acquired, the electric motor 24 is controlled so that the actual braking force approaches the target braking force.
In the present embodiment, when the drum brake 6 is applied while the vehicle is moving forward, the load F applied by the brake shoe 20b contacting the anchor member 16 is detected by the load detection device 36, and based on the load F. A case where the braking force B applied to the wheels is required will be described. Since a predetermined relationship is established between the brake force B and the load F as shown in FIG. 4, the brake force B can be obtained based on the load F.
On the other hand, the load F does not necessarily act in the tangential direction of the anchor member 16 (the direction perpendicular to the end face FA of the load application portion 50). When the load F acts in a direction parallel to the tangential direction, the magnitude of the load F is detected by the load detection device 36. When the load F acts in a direction inclined with respect to the tangential direction, the load F That is, the magnitude of the tangential component is detected. Further, since the acting direction of the load F is determined by the structure and shape of the drum brake 6, the relationship between the tangential direction component of the load F and the load F is known. Therefore, based on the tangential component of the load F, the braking force can be acquired.
Hereinafter, the load F and the tangential component of the load F are referred to as the load F without being distinguished.

As shown in FIG. 3, the load F acts on the load acting part 50. However, since the load acting part 50 is a rigid body, the load F and the forces F ₁ and F ₂ received by the connecting parts 54 and 56 and the compression force detection are detected. The force F ₃ received by the element 40 is balanced.
F = F ₁ + F ₂ + F ₃ (1)
Moreover, the load action part 50 does not bend when the load F acts. The compressive force detecting element 40 is provided at the midpoint between the connecting portions 54 and 56. Therefore, there is an expression (δ ₁ + δ ₂ ) between the contraction or expansion (compression amount or expansion amount) δ ₁ and δ _{2 of} the connecting portions 54 and 56 and the contraction (compression amount) δ ₃ of the compression force detecting element 40. / 2 = δ ₃ (2)
Is established.
The cross-sectional areas of the connecting portions 54 and 56 are all the same A ₀ , the Young's modulus of the anchor member 16 is E ₀ , the cross-sectional area of the compressive force detecting element 40 is A and the Young's modulus E,
K ₀ = A ₀ · E ₀ / w ₁
K = A · E / (w ₁ −Δw ₁ )
Then, δ ₁ , δ ₂ , and δ ₃ can be expressed by (F ₁ / K ₀ , F ₂ / K ₀ , F ₃ / K), respectively. Can be rewritten.
F ₁ + F ₂ = F ₃ · K ₀ / 2K (3)
Although K ₀ and K are constants, Δw ₁ is a small value in the constants K ₀ and K. Therefore, the tangential dimension w ₁ and (w ₁ −Δw ₁ ) may be the same value. .
From these formulas (1) and (3), the load F is given by the formula F = F ₃ (1 + 2K ₀ / K) (4)
Can be asked according to.
In the equation (4), if the value detected by the compressive force detecting element 40 is substituted for F ₃ , the load F can be acquired, and from the predetermined relationship between the load F and the brake force B, The braking force B can be acquired.

As described above, in this embodiment, the compressive force detecting element 40 is fixed by press-fitting the insert 58, and is not bonded by an adhesive. Therefore, it is possible to make it difficult for the compressive force detecting element 40 to be peeled off or to be displaced as compared with the case where it is fixed using an adhesive. In addition, the manufacturing process can be simplified as compared with the case of fixing using an adhesive. Furthermore, by adjusting the press-fit allowance Δw ₂ and the gap Δw ₁ of the insert 58, it is possible to adjust the applied load of the compressive force detecting element 40 to a desired size.
Further, the compressive force detecting element 40 has a structure that receives the load F via the load acting part 50 that is a rigid body, and the load applied to the load acting part 50 includes a pair of connecting parts 54 and 56, It is set as the structure which the compressive force detection element 40 in the middle receives. As a result, it is possible to make it difficult for bending force to be applied to the compressive force detecting element 40 due to the eccentric load, and accordingly, the durability of the compressive force detecting element 40 can be improved and the life can be extended.
In the present embodiment, the brake force acquisition device is configured by a portion for acquiring the brake force of the load detection devices 36 and 38 and the brake ECU 80, a portion for storing the table represented by the map of FIG.

In the above embodiment, the compressive force detecting element 40 is located in the center of the element holding hole 42 in the radial direction, and the spaces 70 and 72 are provided on both sides. However, as shown in FIG. Very small interposition members 80, 82 can be provided. The Young's modulus E _n of the interposed members 80 and 82 is smaller than the Young's modulus E ₀ of the anchor member 16 and the Young's modulus E of the compressive force detecting element 40 (E _n <E ₀ and E _n <E). Since the interposition members 80 and 82 are members having a small Young's modulus, even if the insert 58 is press-fitted into the insert hole 44, it can be easily deformed. Further, when obtaining the magnitude of the load F, it can be ignored. If the interposition members 80 and 82 are thus provided, the positioning accuracy of the compressive force detecting element 40 can be improved.

In the above embodiment, the compressive force detecting element 40 is fixed by applying a predetermined pressing force by the press-fitting of the insert 58. However, the pressing force applied to the compressive force detecting element 40 is fixed. The (grip force) can also be adjustable.
An example in that case is shown in FIG. In this embodiment, the brake force acquisition device includes a gripping force adjustment device 90. As shown in FIGS. 6A and 6B, the gripping force adjusting device 90 adjusts the pressing force to the compressive force detecting element 40 by moving the insert in the tangential direction. Provided on the outer portion of the pin 18. The gripping force adjusting device 90 includes a pair of nestings 102 and 104 each having an inclined surface, and a screw mechanism 106. On the other hand, the compressive force detecting element 40 is disposed in the element holding hole 108 formed in the anchor member 92. The element holding hole 108 is surrounded by the connecting portions 54 and 56 and the load acting portion 50 in three directions (on both sides in the radial direction and the side where the brake shoe 20b in the tangential direction abuts). It is opened on the opposite side to the gripping force adjusting device 90. Therefore, the compressive force detecting element 40 disposed in the element holding hole 108 can be brought into contact with the nest 102 of the gripping force adjusting device 90.
The inserts 102 and 104 have inclined surfaces 110 and 112 that are inclined in a tangential direction with respect to the rotation axis of the wheel, and the inclined surfaces 110 and 112 are disposed in surface contact with each other. The inclined surfaces 110 and 112 are inclined so that the distance from the end surface FA of the anchor member 92 increases as the distance from the backing plate 8 increases.
The insert 102 is held on the main body of the anchor member 92 so as to be relatively movable in the tangential direction. Further, the inclined surface 110 of the nest 102 and the surface 114 opposite to the tangential direction are in surface contact with the compressive force detecting element 40.
The nest 104 is held so as to be relatively movable in the direction of the rotational axis of the wheel. A cylindrical female screw portion 122 is fixed to the insert 104, and a male screw 124 is screwed onto the inner peripheral side of the female screw portion 122. The male screw 124 is provided with the head protruding from the anchor member 92.
When the nest 104 is relatively moved in the direction of the axis of rotation of the wheel in a direction away from the backing plate 8 by the rotation of the male screw 124, the nest 102 is relatively moved in the tangential direction, and a pressing force is applied to the compression force detecting element 40. It is done. The compressive force detecting element 40 is gripped by the insert 102 or the like (gripping force adjusting device 90) and the load acting unit 50. When the tightening force of the male screw 124 is increased, the pressing force applied to the compression force detecting element 40 is increased, and the applied load is increased.
As described above, the pressing force is applied to the compressive force detecting element 40 and gripped. However, when the applied load increases, the minimum compressive force that can be detected by the compressive force detecting element 40 increases accordingly (0 point). The offset is large), which is undesirable.
Therefore, in this embodiment, the tightening load of the male screw 124 is adjusted so that the pressing force and the zero point offset have a desired magnitude. For example, the pressing force applied to the compression force detecting element 40 is shown in FIG. The size is adjusted within a range R shown in FIG. The vertical axis in FIG. 6 is the pressing force (load) applied to the compressive force detecting element 40, but the pressing force applied to the compressive force detecting element 40 can be understood by looking at the output of the compressive force detecting element 40. . Therefore, the pressing force can be adjusted while looking at the output of the compressive force detecting element 40.
As described above, when the gripping force adjusting device 90 is provided, the compressive force detecting element 40 can be satisfactorily fixed to the anchor member 92. Further, when the pressing force is loosened by the operation of the drum brake 6, it can be easily adjusted by operating the male screw 124.

Another gripping force adjusting device 200 is shown in FIGS. 8 (a) and 8 (b). In the present embodiment, the inclination directions of the inclined surfaces 206 and 208 of the pair of inserts 202 and 204 are opposite to those in the third embodiment. The inclined surfaces 206 and 208 are inclined so as to approach the end surface FA as they are separated from the backing plate 8 in the rotational axis direction of the wheel.
The nest 202 is held on the main body of the anchor member 210 so as to be relatively movable in the tangential direction, and a surface 212 opposite to the inclined surface 206 is in contact with the compressive force detecting element 40.
The nest 204 is held by the main body of the anchor member 210 so as to be relatively movable in a direction parallel to the rotation axis of the wheel. The end surface of the bolt 220 abuts on a surface 214 orthogonal to the rotation axis of the wheel of the nest 204. The bolt 220 is screwed into a female screw portion provided in the anchor member 210 at the male screw portion, and is screwed into the nut 224 so that the head portion protrudes outward from the anchor member 210.
By tightening the bolt 220 with the nut 224 loosened, when the nest 204 is brought close to the backing plate 8, the nest 202 is relatively moved in the tangential direction, and a pressing force is applied to the compression force detecting element 40. The compressive force detecting element 40 is gripped by the load acting unit 50 and the insert 202 or the like (gripping force adjusting device 200). If the tightening force of the bolt 220 is increased, the gripping force of the compression force detecting element 40 can be increased, and the applied load is increased.
Also in the present embodiment, as in the case of the above embodiment, the gripping force and the set load applied to the compression force detecting element 40 are adjusted so as to have a desired magnitude. If the nut 224 is tightened after the adjustment, the pressing force can be maintained.

In the above embodiment, the compressive force detecting element is fixed by the press-fitting of the insert. However, it can be fixed using an adhesive.
An example of such a case is shown in FIGS. 9 (a) and 9 (b). In the load detection device 298 shown in FIG. 9 (a), an element holding recess having an opening on the outer side of the pin 18 of the anchor member 300 in the rotational axis direction of the wheel and having an opening on the inner end surface in the radial direction. 302 is formed, and the compressive force detecting element 304 is fixed to the recess 302 with an adhesive. Further, the bottom portion 306 of the element holding recess 302 is a connecting portion 306, and the wall on the end face FA side of the anchor member 300 of the element holding recess 302 is a load acting wall 308. In the present embodiment, one connecting portion 306 is provided. Further, the compressive force detecting element 304 is gripped by the load acting portion 308 and the portion 310 inside the anchor member 300 of the element holding recess 302.
The load F acting on the load acting portion 308 is received by the compressive force detecting element 304 and the connecting portion 306, and the load F can be detected in the same manner as in the first embodiment. Also in this embodiment, even if a bending moment due to the eccentric load occurs, it is possible to make it difficult for the bending force to act on the compressive force detecting element 304.

In the load detection device 348 shown in FIG. 9B, the anchor member 350 is formed with an element holding recess 352 that penetrates in the wheel rotation axis direction and has an opening on the outer end surface in the radial direction. The compression force detection element 354 is fixed to the adhesive 352 with an adhesive. The bottom portion 356 of the element holding recess 352 is a connecting portion 356, and the wall on the end face FA side of the anchor member 350 of the element holding recess 352 is a load acting portion 358.
The load F acting on the load acting portion 358 is received by the compressive force detecting element 354 and the connecting portion 356, and the load F can be detected as in the first embodiment. In this embodiment, even if a bending moment due to the eccentric load is generated, it is possible to make it difficult for the bending force to act on the compressive force detecting element 304.

In the above-described embodiment, the load detection device is provided inside the anchor member. However, the load detection device may be formed of a member different from the anchor member and attached to the anchor member 16. The effect of can be produced.
Further, the structure of the pressing mechanism 14 and the structure of the drum brake 10 are not limited. For example, a duo-servo type drum brake or a two-leading type drum brake may be used. It can also be applied to disc brakes. Further, the pressing mechanism 14 may be operated by hydraulic pressure.
The present invention can be practiced in various modifications and improvements based on the knowledge of those skilled in the art, in addition to the aspects described above.

  16, 120, 210, 300, 350: Anchor member 36, 38, 298, 348: Load detection device 90, 200: Gripping force adjustment device 40, 304, 354: Compression force detection element 42, 108: Element holding hole 44 : Nesting press-fit hole 50: Load acting part 54, 56: Connection part 58, 102, 104, 202, 204: Nesting 70, 72: Space 80, 82: Interposition member

Claims (6)

A brake force acquisition device for detecting a brake force actually applied to the wheel of a brake in which a friction member held by a non-rotating body is slidably contacted with a friction surface of a brake rotating body that rotates together with the wheel. There,
It is fixed to the non-rotating body and is provided on a load receiving member that receives a load by contacting the friction member when the brake is applied,
(i) a compressive force detecting element that is gripped by a rigid body in a direction parallel to an acting direction of a load received by contact with the friction member and detects a compressive force applied by the load;
(ii) A braking force acquisition device comprising: a connecting member that is provided on at least one side of the compressive force detecting element in a direction intersecting with the direction in which the load is applied and receives a part of the load.   2. The brake force acquisition device according to claim 1, wherein the connecting member is provided on each side of the compressive force detecting element in a direction orthogonal to a tangential plane of the friction surface of the brake rotating body of the load receiving member.   The brake force acquisition device according to claim 1, wherein a space is provided between the connecting member and the compressive force detection element.   An interposition member having a Young's modulus smaller than the Young's modulus of the connecting member and smaller than the Young's modulus of the compressive force detecting element is provided between the connecting member and the compressive force detecting element. The brake force acquisition device described in 1.   The load receiving member is provided on the side of the compressive force detecting element opposite to the side in which the friction member abuts in the direction of the load, and applies a force in a direction parallel to the direction of the load to the load receiving member. The brake force acquisition device according to any one of claims 1 to 4, further comprising a gripping force adjustment device that holds the compression force detection element by applying the force and that can adjust a force applied to the compression force detection element. .   The brake rotating body is a drum that rotates together with the wheel, the load receiving member is an anchor fixed to a backing plate as the non-rotating body, and the friction member is on both sides of the anchor of the backing plate. The brake force acquisition device according to any one of claims 1 to 5, wherein the brake shoe is a pair of arcuate brake shoes held in a relatively movable manner.

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