JP3847378B2 - Drum brake device - Google Patents

Description

【００２９】
表１から明らかなように、本発明のドラムブレーキ装置は、通常の使用範囲であるいずれの摩擦係数の場合（μ＝０．３〜０．５）でも、従来のリーディングトレーリング式よりも１５〜２０％程度優れたブレーキ効率が得られ、ブレーキ性能を同じにすれば、従来のものよりもドラム径を１サイズ以上小さくして、軽量化とコストの低減を実現し得ることが確認できた。
【００３０】
【発明の効果】
本発明のドラムブレーキ装置によれば、例えば、ドラムの前進回転時の制動時には、前記第１のブレーキシューはリーディング・シューとして、また、第２のブレーキシューはトレーリング・シューとして作動する構成であるが、その制動動作時には、第１のブレーキシューの端部の支持穴を挿通しているアンカーピンに作用するアンカ反力の一部が、前記支持穴の第１の当接面とアンカーピンとの接触によって、第２のブレーキシューの端部を付勢する力として作用する。そして、この第１のブレーキシューから第２のブレーキシューへの付勢力は、該第２のブレーキシューの端部の支持穴の第２の当接面とアンカーピンとの当接によって、当該第２のブレーキシューのドラムへの押圧力を増大させるモーメントに変換させられる。
【００３１】
そこで、リーディング・シュー側と比較してトレーリング・シュー側はドラムとの接触面圧が小さくなるという従来のリーディングトレーリング式の弱点を改善し、小型でも、ブレーキの効きが優れたブレーキ装置とすることができる。
また、各ブレーキシューの組み付けで、各ブレーキシューの他方の対向端相互を浮動ピンを介して当接させると共に、浮動ピンを介して当接する各ブレーキシューの端部に形成した支持穴にアンカーピンを遊嵌させた点を除けば、従来のリーディングトレーリング式と同様の構成で良く、ホイールシリンダも単一の装備で足りるため、安価であり、しかも駐車ブレーキ装置が組み込み易いという従来のリーディングトレーリング式が有していた長所はそのまま受け継ぐことができる。
従って、従来のリーディングトレーリング式よりもブレーキの効きが高く、しかも、ツーリーディング式やデュオサーボ式と比較すれば、ブレーキの効きが安定し、かつ、駐車ブレーキ装置の組み込みも容易にでき、ドラムブレーキ装置の小型化とコストの低減を実現することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係るドラムブレーキ装置の正面図である。
【図２】図１に示したドラムブレーキ装置のＡ−Ａ断面矢視図である。
【図３】図１に示したドラムブレーキ装置のアンカー部における動作説明図である。
【符号の説明】
１ ドラムブレーキ装置
２ ドラム
４ 第１のブレーキシュー
４ａ，５ａ リム
４ｂ，５ｂ ウェブ
４ｃ，５ｃ ライニング
５ 第２のブレーキシュー
７ ホイールシリンダ
９ 浮動ピン
１１，１２ 支持穴
１４ バッキングプレート
１６ アンカーピン
１９ 引張りばね
２１ 第１の当接面
２２ 第２の当接面
２３ 連結板
２４ ピン挿入孔
２６ 止め輪[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brake device used in a vehicle or the like, and more particularly to a drum brake device that generates a braking force by pressing an opposing brake shoe against an inner surface of a drum.
[0002]
[Prior art]
A drum brake device used in a vehicle or the like generally includes an input unit (wheel cylinder), a brake shoe that generates a braking force by being expanded in the drum by a force from the input unit, and an anchor unit that supports the brake shoe. The structure which comprised was comprised. And, the input shoe is on the inlet side (or intervention side) with respect to the rotation direction of the drum, the anchor part is on the outlet side (or intervention side), the leading shoe, the anchor part is the inlet side (or intervention side), A device in which the input portion is on the exit side (or the intervention side) is called a trailing shoe.
[0003]
As a conventional drum brake device, those of a leading trailing type, a two leading type, a duo servo type and the like are used.
In the leading trailing type, a wheel cylinder that expands the brake shoe is arranged between one opposing ends of a pair of opposing brake shoes, and an anchor portion is arranged between the other opposing ends, thereby A pair of brake shoes acting as a trailing shoe is incorporated, the braking effectiveness is stable, and a parking brake device can be easily incorporated.
[0004]
The two-reading type is a structure that incorporates two reading shoes. Among them, the single-acting type (TP1W) has a higher gain when moving forward and two-trailing when moving backward, and gains more than when moving forward. Decreases. The two-leading double-acting type (TP2W) has the same effect for both forward and backward travel and a high gain.
[0005]
Duo-servo type is a high gain brake that has the same effect in both forward and reverse movements by connecting two shoes to link and using the braking force generated in the primary shoe as the input of the secondary shoe. To satisfy the requirements, it may be smaller than the leading trailing type, and the parking brake device can be easily incorporated.
[0006]
[Problems to be solved by the invention]
However, while the leading trailing type is excellent in stability, the braking effect is low, and particularly as a parking brake, it has been an obstacle to reducing the size and weight of the drum brake.
The two-leading type is expensive because two wheel cylinders are required, and the parking brake mechanism is complicated. The duo-servo type has a problem that the braking effectiveness is low. is there.
[0007]
Accordingly, an object of the present invention is to eliminate the above-mentioned problems, and a small and inexpensive drum brake device that has a higher braking effect than the leading trailing type and has a more stable braking effect than the two leading type or duo servo type. Is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a drum brake device according to the present invention includes a first and a second pair of brake shoes disposed opposite to a cylindrical drum inner space, and a pair of the opposite brake shoes. A wheel cylinder that is disposed between one opposing ends and expands the pair of brake shoes, a floating pin held by the other opposing ends of the pair of brake shoes, and each opposing each other across the floating pin A support hole formed at the end of the brake shoe and a pair of anchor pins fixed to the backing plate so as to be loosely fitted into the support hole at the end of each brake shoe. A drum brake device in which the other brake shoe operates as a trailing shoe as a leading shoe,
In the support holes formed at the ends of the brake shoes, a part of the anchor reaction force that abuts the anchor pin and acts on the anchor pin when operating as a leading shoe is opposed to the floating pin via the floating pin. A first abutting surface that acts on the end of the other brake shoe, and an abutment pin that acts on the anchor pin when operated as a trailing shoe, and applies an urging force through the floating pin to the drum of the brake shoe And a second abutting surface for converting to an urging force that increases the pressing force.
[0009]
Preferably, the opposing ends of the first and second pair of brake shoes that contact the floating pin have an initial position return contact surface that returns the end of each brake shoe to the initial position when the braking operation is released. Provided.
[0010]
According to the above configuration, for example, at the time of braking during forward rotation of the drum, the first brake shoe operates as a leading shoe and the second brake shoe operates as a trailing shoe. During the braking operation, a part of the anchor reaction force acting on the anchor pin inserted through the support hole at the end of the first brake shoe is brought into contact with the first contact surface of the support hole and the anchor pin. This acts as a force for urging the end portion of the second brake shoe. The urging force from the first brake shoe to the second brake shoe is caused by the contact between the second contact surface of the support hole at the end of the second brake shoe and the anchor pin. It is converted into a force that increases the pressing force of the brake shoe to the drum.
[0011]
Therefore, compared with the leading shoe side, the trailing shoe side has a reduced contact surface pressure with the drum, which improves the weakness of the conventional leading trailing type. can do.
In addition, when assembling each brake shoe, the other opposing ends of each brake shoe are brought into contact with each other via a floating pin, and an anchor pin is inserted into a support hole formed at the end of each brake shoe that comes into contact with the floating pin. Except for the point of loose fitting, the configuration is the same as that of the conventional leading trailing type, and the wheel cylinder is sufficient as a single equipment, so it is inexpensive, and the support hole at the end of the brake shoe is abutted. Effectiveness can be controlled by appropriately adjusting the angle of the surface and the position of the anchor pin. Moreover, the advantage of the conventional leading trailing type that the parking brake device can be easily incorporated can be inherited as it is.
[0012]
Therefore, the braking effect is higher than the conventional leading trailing type, and compared to the two leading type or duo servo type, the braking effect is stable and the parking brake device can be easily incorporated. It is possible to reduce the size and cost of the brake device.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
1 to 3 show an embodiment of a drum brake device according to the present invention, FIG. 1 is a front view of the drum brake device 1 according to the present invention, and FIG. 2 is a diagram of the drum brake device 1 of FIG. AA sectional view of the anchor portion, FIG. 3 is an operation explanatory diagram in the anchor portion in the drum brake device 1 of FIG.
[0014]
The drum brake device 1 according to the present embodiment includes a first and second pair of brake shoes 4, 5 disposed opposite to an inner space of a cylindrical drum 2, and one of the opposed pair of brake shoes 4, 5. A wheel cylinder 7 which is disposed between the opposite ends of the pair of brake shoes 4 and 5 and expands the pair of brake shoes 4 and 5, a floating pin 9 which is held by the other opposite ends of the pair of brake shoes 4 and 5, Support holes 11 and 12 formed at the ends of the brake shoes 4 and 5 facing each other with the floating pin 9 interposed therebetween, and a pair of fixedly attached to the backing plate 14 so as to be loosely fitted in these support holes 11 and 12 Anchor pins 16 and 16 are provided.
[0015]
The pair of brake shoes 4 and 5 includes arcuate plate-like rims 4a and 5a along the inner peripheral surface of the drum 2, webs 4b and 5b protruding from the rims 4a and 5a toward the inner diameter side, and the rims 4a and 5a. It consists of linings 4c and 5c stuck on the outer periphery. Each brake shoe 4, 5 is attached to the backing plate 14 by a hold-down device 8 so as to be able to advance and retreat toward the inner peripheral surface of the drum 2.
[0016]
The ends of the pair of brake shoes 4, 5 on the backing plate 14 facing each other are urged by the tension springs 18, 19 toward each other (ie, away from the drum 2). .
The support holes 11 and 12 formed at the ends of the brake shoes 4 and 5 are provided with a first contact surface 21 and a second contact surface 22.
[0017]
The first abutment surface 21 abuts against the anchor pin 16 when operating as a leading shoe, and a part of the anchor reaction force ΔF acting on the anchor pin 16 is passed through the floating pin 9. It is made to act on the edge part of the other brake shoe which is facing.
Anchor reaction force in leading shoe, as shown in FIG. 3, the component F _y in the substantially radial direction and the direction (i.e., circumferential direction) perpendicular to the said component F _y can be decomposed into a component F _x of. Such a circumferential component F _x of the anchor reaction force is assigned to the biasing force ΔF acting on the end of the trailing shoe from the leading shoe through the floating pin 9.
[0018]
The second abutment surface 22 abuts against the anchor pin 16 when operated as a trailing shoe, and applies the urging force ΔF from the leading shoe via the floating pin 9 to the drum of the brake shoe. This is converted to a moment M that increases the pressing force to the.
In the case of the present embodiment, as shown in FIG. 3, the first contact surface 21 is an inclined surface having an inclination angle of an angle α with respect to the opposing direction of the pair of brake shoes (the left-right direction in FIG. 3). It is said. Further, the second contact surface 22 is an inclined surface having an inclination angle of an angle β with respect to a direction (vertical direction in FIG. 3) orthogonal to the opposing direction of the pair of brake shoes.
[0019]
In addition, when the anchor pin 16 comes into contact with the first contact surface 21 or the second contact surface 22 described above, the support pins 11 and 12 contact the anchor pin 16 with these contact surfaces. as movable in a direction perpendicular to the ends of the brake shoes direction of the biasing force [Delta] F, or the anchor reaction force F _t in the state, is larger opening than the cross section of the anchor pin 16.
[0020]
In the case of the present embodiment, the opposed end surfaces 4 d and 5 d of the first brake shoe 4 and the second brake shoe 5 that contact the floating pin 9 are arcuate surfaces that circumscribe the floating pin 9. These end faces 4d and 5d have a structure that does not prevent the relative movement of the first and second brake shoes 4 and 5 in the substantially Y-axis direction during the braking operation, so that the trailing shoe has the effect of the leading shoe. It functions so as not to receive. Therefore, the adhesion of the lining to the drum is improved. The end surfaces 4d and 5d function as initial position return contact surfaces that return the end portions of the brake shoes 4 and 5 to the initial positions when the braking operation is released.
[0021]
As is clear from FIGS. 1 and 2, each anchor pin 16 has an upper end penetrating through the pin insertion hole 24 of the connecting plate 23, and a retaining ring 26 is attached to a portion protruding from the connecting plate 23. Are connected to each other and are prevented from falling off.
In the drum brake device 1 described above, for example, during braking when the drum 2 rotates forward (rotation in the direction of arrow (A) in FIG. 1), the first brake shoe 4 is moved along with the extension of the wheel cylinder 7. As a leading shoe, the second brake shoe 5 operates as a trailing shoe.
[0022]
During such a braking operation, a part of the anchor reaction force that acts on the anchor pin 16 inserted through the support hole 11 at the end of the first brake shoe 4 is the first contact of the support hole 11. The contact between the contact surface 21 and the anchor pin 16 acts as a force ΔF that urges the end portion of the second brake shoe 5. The urging force ΔF from the first brake shoe 4 to the second brake shoe 5 causes the second contact surface 22 of the support hole 12 at the end of the second brake shoe 5, the anchor pin 16, and the like. Is a moment M that increases the pressing force of the second brake shoe 5 against the drum.
[0023]
Therefore, compared with the leading shoe side, the trailing shoe side has a reduced contact surface pressure with the drum, which improves the weakness of the conventional leading trailing type. can do.
In addition, when the brake shoes 4 and 5 are assembled, the other opposing ends of the brake shoes 4 and 5 are brought into contact with each other through the floating pin 9, and the brake shoes 4 and 5 that are in contact with each other through the floating pin 9. Except for the point that the anchor pins 16 and 16 are loosely fitted in the support holes 11 and 12 formed at the ends of the front end, the same configuration as that of the conventional leading trailing is sufficient, and the wheel cylinder 7 is also sufficient with a single equipment. The advantage of the conventional leading trailing type that is inexpensive and easy to incorporate a parking brake device can be inherited as it is.
[0024]
Therefore, the braking effect is higher than the conventional leading trailing type, and compared to the two leading type or duo servo type, the braking effect is stable and the parking brake device can be easily incorporated. The brake device 1 can be reduced in size and cost.
[0025]
When the drum rotates backward, the first brake shoe 5 operates as a leading shoe and the first brake shoe 4 operates as a trailing shoe, so that the same effect can be obtained. The support hole 11 provided in the shoe 4 and the support hole 12 provided in the second brake shoe 5 are set symmetrically with each other.
[0026]
Note that the angle α of the first contact surface 21 and the angle β of the second contact surface 22 are not limited to the values in the present embodiment, and the effectiveness of the brake can be controlled by various design changes. Is possible. Each of the contact surfaces 21 and 22 is a simple inclined surface in the present embodiment, but may be a curved surface such as an arc surface.
[0027]
【Example】
In order to confirm the improvement of the braking effectiveness of the drum brake device 1 in the above-described embodiment, the inventors of the present application use various brake shoes 4 and 5 having different friction coefficients of the linings 4c and 5c, and the braking effectiveness ( BEF) was calculated. Further, the same calculation was performed by assembling the same brake shoes 4 and 5 as a comparative example to a conventional leading trailing type or two leading type.
The brake effectiveness (BEF) comparison table based on the calculation results is shown in Table 1 below. In Table 1, the drum brake device according to the present invention has a second contact surface 22 with an inclination angle β = 35 °. In Table 1, LT represents a conventional reading trailing type, and 2L represents a two reading type.
[0028]
[Table 1]

[0029]
As is apparent from Table 1, the drum brake device of the present invention is 15% more than the conventional leading trailing type at any friction coefficient (μ = 0.3 to 0.5) in the normal use range. It was confirmed that a brake efficiency superior to about 20% can be obtained, and if the brake performance is the same, the drum diameter can be reduced by one size or more compared with the conventional one, and the weight can be reduced and the cost can be reduced. .
[0030]
【The invention's effect】
According to the drum brake device of the present invention, for example, at the time of braking during forward rotation of the drum, the first brake shoe operates as a leading shoe and the second brake shoe operates as a trailing shoe. However, during the braking operation, a part of the anchor reaction force acting on the anchor pin inserted through the support hole at the end of the first brake shoe is caused by the first contact surface of the support hole and the anchor pin. Acts as a force for urging the end of the second brake shoe. The urging force from the first brake shoe to the second brake shoe is caused by the contact between the second contact surface of the support hole at the end of the second brake shoe and the anchor pin. It is converted into a moment that increases the pressing force of the brake shoe to the drum.
[0031]
Therefore, compared with the leading shoe side, the trailing shoe side has improved the weakness of the conventional leading trailing type that the contact surface pressure with the drum is reduced, and the brake device has excellent braking effectiveness even with a small size. can do.
In addition, when assembling each brake shoe, the other opposing ends of each brake shoe are brought into contact with each other via a floating pin, and an anchor pin is inserted into a support hole formed at the end of each brake shoe that comes into contact with the floating pin. Except for the point of loose fitting, the configuration is the same as that of the conventional leading trailing type, and the wheel cylinder is sufficient with a single equipment, so it is inexpensive and easy to incorporate a parking brake device. The advantages of the ring type can be inherited as they are.
Therefore, the braking effect is higher than the conventional leading trailing type, and compared to the two leading type or duo servo type, the braking effect is stable and the parking brake device can be easily incorporated. It is possible to reduce the size and cost of the brake device.
[Brief description of the drawings]
FIG. 1 is a front view of a drum brake device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the drum brake device shown in FIG.
3 is an operation explanatory diagram of an anchor portion of the drum brake device shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drum brake device 2 Drum 4 1st brake shoes 4a, 5a Rim 4b, 5b Web 4c, 5c Lining 5 2nd brake shoes 7 Wheel cylinder 9 Floating pin 11, 12 Support hole 14 Backing plate 16 Anchor pin 19 Tension spring 21 First contact surface 22 Second contact surface 23 Connecting plate 24 Pin insertion hole 26 Retaining ring

Claims (2)

A pair of first and second brake shoes disposed opposite to each other in the cylindrical drum inner space, and the pair of brake shoes disposed between the opposite ends of the pair of brake shoes are expanded. A wheel cylinder, a floating pin held by the other opposed ends of the pair of brake shoes, a support hole formed at an end of each brake shoe facing the floating pin, and an end of each brake shoe A pair of anchor pins fixed to the backing plate to fit loosely into the support holes of the part, and during braking operation, one brake shoe acts as a leading shoe and the other brake shoe acts as a trailing shoe A drum brake device for
In the support holes formed at the ends of the brake shoes, a part of the anchor reaction force that abuts the anchor pin and acts on the anchor pin when operating as a leading shoe is opposed to the floating pin via the floating pin. A first abutting surface that acts on the end of the other brake shoe, and an abutment pin that acts on the anchor pin when operated as a trailing shoe, and applies an urging force through the floating pin to the drum of the brake shoe A drum brake device, comprising: a second abutting surface that converts an urging force that increases a pressing force. The opposing end of the first and second pair of brake shoes that contact the floating pin is provided with an initial position return contact surface that returns the end of each brake shoe to the initial position when the braking operation is released. The drum brake device according to claim 1, wherein

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