JP4825843B2 - Brake device - Google Patents

Description

  The present invention relates to a drum brake device with a braking arm.

  As a brake device, a braking piece held by a brake arm that is pivotally supported comes into contact with a braking surface of a brake drum as a braked body, presses the braking arm with a braking spring, and resists the spring force of the braking spring. In some cases, the braking arm is released by driving the braking arm. For example, a driving means such as an electromagnet has been proposed. In the direction perpendicular to the length direction of the braking arm, the force of the braking spring and the driving means acts on the braking arm, and the direction is the same. A pressing force acts on the brake drum by the brake piece. As an example, the length direction of the braking arm is installed in the gravity direction (see, for example, Patent Document 1), and as another example, the length direction of the braking arm is installed in the horizontal direction with the gravity direction as the vertical direction. There are some (see, for example, Patent Documents 2 and 3).

  In the case of Patent Document 1, the weights of the braking arm, the braking piece, the braking spring, and the movable part of the driving means hardly act as a pressing force to the brake drum. The weight of the arm, the brake piece, the brake spring, the movable part of the driving means, etc. acts as a pressing force to the brake drum.

That is, in the case of Patent Documents 2 and 3, the upper brake arm, the brake piece, the brake spring, and the movable part of the driving means are increased in pressure with respect to the brake drum pressing force due to the spring force of the braking spring, and the lower braking force is applied. The arm, the brake piece, the brake spring, and the movable part of the driving means have a reduced pressing force.
JP 2006-266362 A JP 2008-7247 A Japanese Patent Laid-Open No. 2005-219843

  The brake devices proposed in Patent Documents 2 and 3 are configured such that the braking arm is installed in the lateral direction and a pressing force is applied in the direction of gravity, and the braking arm, the braking piece, the braking spring, and the electromagnetic device are movable. The weight of the part or the like is an increase / decrease pressing force to the brake drum.

  That is, with respect to the brake drum pressing force due to the spring force of the braking spring, the upper braking arm and the braking piece have an increased pressing force. It becomes pressure. That is, the pressing force is unbalanced between the upper and lower braking pieces.

  Therefore, the pressing force of the upper and lower braking pieces is different, so that there is a problem that the amount of wear of the braking piece becomes unbalanced, the wear of the braking piece with the higher pressing force is large, the replacement is accelerated, and the maintainability is deteriorated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a brake device that corrects an imbalance in the pressing force of the brake piece to the brake drum and improves an unbalance in the wear of the brake piece to improve the maintainability.

To achieve the above object, the present onset Ming is installed in the horizontal direction with the braking members disposed on the upper side and the lower side facing the braking surface of the brake drum as the braked member, these brake piece A pair of brake arms that are pivotally supported, a brake spring that applies pressure to each of the brake arms so that the brake piece presses the brake surface and brakes the brake drum, and a spring force of the brake spring Driving means for driving each of the braking arms to release the pressure of the braking pieces and releasing the braking of the brake drum, and the braking pieces, braking arms, braking springs, movable parts of the driving means, etc. The pressing force to the brake drum is generated by the weight of the mechanism element, and the upper braking arm and the braking piece increase the pressing force, the lower braking arm and the braking force with respect to the brake drum pressing force by the spring force of the braking spring. One side is reduced pressure A brake apparatus comprising, providing a pressing force correction means for correcting the unbalance of the increase pressing force of the pressing force and reduced pressing force to the brake drum of said braking members to the braking arm, the pressing force correction means the braking It is an external force applying means provided on the arm .

  As a result, an unbalance of the pressing force of the brake piece to the brake drum is corrected, and an unbalance of the brake piece wear is improved, so that a brake device with good maintainability can be obtained.

Further, the present invention is characterized in that the external force adding means is a pressing force correction weight provided on the braking arm .

As a result, a brake device similar to that of the above-described invention can be obtained , and the pressing force can be corrected by adding the pressing force correction weight provided on the braking arm .

Further, the present invention is characterized in that the external force adding means is a pressing force correction spring provided on the braking arm .

As a result, a brake device similar to that of the above invention can be obtained, and a simple configuration capable of correcting the pressing force by adding a spring can be obtained .

In the present invention, an insulator is provided between the braking arm and the driving means, and the braking arm is driven by the driving means via the insulator, and the pressing force of the braking piece to the brake drum is not reduced. A pressing force correcting means is provided in at least one of the braking arm and the lever for balancing .

As a result, a brake device similar to that of the above-described invention can be obtained, the disposition of the drive means can be improved, and the drive device can be miniaturized by the lever booster mechanism .

  According to the present invention, a brake device with good maintainability can be obtained by correcting the imbalance of the pressing force of the brake piece to the brake drum and improving the imbalance of the brake piece wear.

  Embodiments of the brake device of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view of the brake device according to the first embodiment of the present invention, and FIG. 2 is a front view of the brake device according to the second embodiment of the present invention.

  A first embodiment will be described with reference to FIG. In FIG. 1, 1 is a brake drum as a braked body, 2a and 2b are a pair of braking arms, and have braking pieces 4a and 4b arranged opposite to the braking surface 3 of the brake drum. It is supported dynamically. Reference numerals 6a and 6b denote braking springs which are provided so as to apply pressure to the braking arms 2a and 2b, respectively, and the braking pieces 4a and 4b press the braking surface 3 to apply braking to the brake drum 1. Reference numerals 7a and 7b denote holding members that hold the brake springs 6a and 6b. Denoted 8a and 8b are driving means for driving the braking arms 2a and 2b against the spring force of the braking springs 6a and 6b, releasing the pressure on the braking pieces 4a and 4b, and releasing the braking of the brake drum 1. To be provided.

  As the driving means 8a and 8b, for example, electromagnetic devices 11a and 11b including an electromagnet 9 and an iron piece 10 electromagnetically attracted to the electromagnet 9 are used. One of the electromagnet 9 and the iron piece 10 is fixed and the other is movable. In this figure, the iron arm 10 is movable and the braking arms 2a and 2b are driven, but conversely, the electromagnet 9 may be movable. Reference numerals 12a and 12b denote springs provided between the electromagnet 9 and the iron piece 10. The springs 12a and 12b apply a tightening force between the electromagnet 9 which is a fixed part of the electromagnetic devices 11a and 11b and the iron piece 10 which is a movable part to prevent rattling. Is.

  Reference numerals 14 a and 14 b denote pressing force correction springs, which are one of the external force addition means 14 as the pressing force correction means 13. That is, the pressing force correcting means 13 is related to the shafts 5a and 5b based on the weights of the movable parts of the braking arms 2a and 2b, the braking pieces 4a and 4b, the braking springs 6a and 6b, the holding members 7a and 7b and the electromagnetic devices 11a and 11b. The external force adding means 14 is arranged on the same side as the center of gravity Gm, Gm ′ of the braking arms 2a, 2b with respect to the shafts 5a, 5b in FIG. In addition, the spring force of the pressing force correction springs 14a and 14b is applied in the direction in which the braking arms 2a and 2b are pulled up. Alternatively, although not shown, the pressing force correction springs 14a, 14b are pressed against the shafts 5a, 5b in the direction of pulling the braking arms 2a, 2b away from the center of gravity Gm, Gm ′ of the braking arms 2a, 2b. You may add the spring force of 14b.

  Similarly, 14c and 14d are pressing force correction weights composed of mass as the external force adding means 14, and are provided for the same purpose as the pressing force correction springs 14a and 14b. In the drawing, the brake arms 2a and 2b are related to the shafts 5a and 5b. It is added to the opposite side of the center of gravity Gm, Gm ′. As will be described later, the spring force of the brake springs 6 a and 6 b also serves as the pressing force correction means 13.

  Next, the operation of the brake device configured as described above will be described.

  For braking, the driving means 8a and 8b are de-energized. For example, if the driving means 8a and 8b are electromagnetic devices 11a and 11b, the electromagnetic force of the electromagnetic coil of the electromagnet 9 is cut off, so that the spring force of the braking springs 6a and 6b is increased. The brake drum 1 is pressed by the braking pieces 4a and 4b via the braking arms 2a and 2b, and the braking state is established. To release the brake, the drive means 8a and 8b are energized. For example, if the drive means 8a and 8b are electromagnetic devices 11a and 11b, the electromagnetic coil of the electromagnet 9 is energized and the spring force of the brake springs 6a and 6b is generated by the electromagnetic attractive force. Accordingly, the braking arms 2a and 2b are driven, and the braking pieces 4a and 4b are separated from the brake drum 1 to release the braking state.

  Next, setting of the spring force of the pressing force correction springs 14a and 14b, the weight of the pressing force correction weights 14c and 14d, and the spring force of the braking springs 6a and 6b of the pressing force correction means 13 will be described.

The pressing forces PB and PB ′ to the brake drum 1 are expressed by the following equations (1) and (2).

  The symbols in the above expressions (1) and (2) are as follows.

PB, PB ': Brake drum 1 pressing force of braking pieces 4a, 4b
W _s , W _s ': Weight of braking pieces 4a, 4b
W _gm , W _gm ': Weight of braking arms 2a, 2b
P _m , P _m ′: spring force of the pressing force correction springs 14a, 14b
W _a , W _a ': Weights of movable parts of the driving means 8a, 8b
P _a, P _a ': driving means 8a, the spring force of the tension spring 8b
P _sp , P _sp ': spring force of the braking springs 6a, 6b
W _r , W _r ′: brake springs 6a, 6b and their holding members 7a, 7b weight
W _m , W _m ′: Pressure correction weights 14c, 14d for the braking arms 2a, 2b
l ₁ , l ₁ ′: distance from the center of rotation of the braking arms 2a, 2b to the pressing portion of the braking pieces 4a, 4b
l ₂ , l ₂ ′: distances from the rotation centers of the braking arms 2a, 2b to the pressing portions of the electromagnetic devices 11a, 11b
l ₃ , l ₃ ′: distances from the rotation centers of the braking arms 2a, 2b to the braking springs 6a, 6b
l _gm , l _gm ': distances from the center of rotation of the braking arms 2a, 2b to the center of gravity Gm, Gm' of the braking arms 2a, 2b
l _wm , l _wm ': distance from the rotation center of the braking arms 2a, 2b to the pressing force correction weights 14c, 14d
l _pm , l _pm ′: distance from the rotation center of the braking arms 2a, 2b to the pressing force correction springs 14a, 14b Note that the symbol “′” is attached to the upper braking arm 2a of the brake drum 1 The symbol relates to the lower braking arm 2b of the brake drum 1.

(A) Correction method using pressing force correction weight W _m , W _m ′
(1), (2) In the equation, damping spring 6a, 6b force P _sp, P _sp '= 0, the pressing force correction spring force P _m, P _m' as = 0, the brake drum 1 pressure PB, PB ' The pressure correction weights W _m and W _m ′ are set so that = 0. That is, the upper braking arm 2a is obtained from the equation (1), and the lower braking arm 2b is obtained from the equation (2).

(B) Correction method using the pressing force correction springs P _m and P _m ′ Similarly to the above (a), in the equations (1) and (2), the braking springs 6a and 6b forces P _sp and P _sp ′ = 0, the pressing force Assuming that the corrected weights W _m and W _m ′ = 0, the pressing force correcting spring forces P _m and P _m ′ are set so that the brake drum 1 pressing force PB and PB ′ = 0. That is, the upper braking arm 2a is obtained from the equation (1), and the lower braking arm 2b is obtained from the equation (2).

(C) Correction method by brake spring force P _sp , P _sp ′ The spring force of the brake springs 6a, 6b also becomes the pressing force correction means 13, and in the same manner as described above, the pressing force correction weight in the equations (1) and (2) Assuming that W _m , W _m ′ = 0, pressing force correction spring force P _m , P _m ′ = 0, the pressing force correction spring force P _sp , P _{sp is set} so that the brake drum 1 pressing force PB, PB ′ = 0. Set '. That is, the upper braking arm 2a is obtained from the equation (1), and the lower braking arm 2b is obtained from the equation (2).

In equations (7) and (8), when P _sp and P _sp ′ are positive, the spring force is added to the predetermined spring force, and when P _sp and P _sp ′ are negative, the spring force is subtracted from the predetermined spring force. Will be set.

(D) Pressure correction weights W _m , W _m ′, pressure correction springs P _m , P _m ′, and spring force P _sp , P _sp ′ of braking springs 6 a, 6 b, a correction method using multiple configurations In the formulas (1) and (2), the pressure correction weight W _m , W _m ′, the pressure correction spring force P _m , P _m ′, and the brake spring 6a are such that the brake drum 1 pressure PB, PB ′ = 0. , 6b forces P _sp and P _sp ′ are represented by the following equations (9) and (10). That is, the upper braking arm 2a is obtained from the equation (1), and the lower braking arm 2b is obtained from the equation (2).

Therefore, for the upper and lower braking arms 2a and 2b, the left side pressing force correction spring forces P _m and P _m ′ and the spring force P _sp of the braking springs 6a and 6b so that the expressions (9) and (10) are satisfied. , P _sp ′, pressing force correction weights W _m , W _m ′ may be set.

  Next, a second embodiment will be described with reference to FIG. This embodiment is different from the first embodiment in that the braking arm is driven through the lever and correction means is added to the braking arm and the lever or the imbalance of the pressing force is corrected by the braking spring. It is. The same parts as those in FIG.

  In FIG. 2, 15a and 15b are levers that are pivotally supported by shafts 16a and 16b, and are connected to the braking arms 2a and 2b by connecting members 17a and 17b, respectively. For example, the electromagnetic devices 11a and 11b described in the first embodiment are used as the driving means 8a and 8b of the levers 15a and 15b, and the levers 15a and 15b are respectively resisted against the spring force of the brake springs 6a and 6b. To release the pressure on the brake pieces 4a and 4b and release the braking of the brake drum 1. When the levers 15a and 15b are arranged at a place different from the arrangement of the driving means 8a and 8b as shown in the first embodiment, the levers 15a and 15b are also utilized. Provided to make the driving means 8a, 8b downsized with a small output.

  Reference numerals 19 a and 19 b denote pressing force correction springs provided on the insulators 15 a and 15 b, which are one of the external force addition means 19 as the pressing force correction means 18. The pressing force correcting means 18 includes the levers 15a and 2b, the brake pieces 4a and 4b, the brake springs 6a and 6b, the holding members 7a and 7b, the levers 15a and 15b, and the lever 15a according to the weight of the movable parts of the electromagnetic devices 11a and 11b. , 15b is configured to cancel out the pressing force of the braking pieces 4a, 4b caused by the moment of the shafts 16a, 16b of the 15b, and the external force adding means 19 is the center of gravity of the levers 15a, 15b with respect to the shafts 16a, 16b in FIG. The spring forces of the pressing force correction springs 19a and 19b are applied in the direction in which the braking arms 2a and 2b are pulled up on the same side as Gs and Gs ′. Alternatively, although not shown, the pressure correction springs 19a and 19b are formed of the pressure correction springs 19a and 19b with respect to the shafts 16a and 16b in a direction to pull down the braking arms 2a and 2b on the opposite side of the center of gravity Gs and Gs ′ of the levers 15a and 15b. A spring force may be added. Similarly, 19c and 19d are pressing force correction weights composed of mass as external force applying means 19 provided on the insulators 15a and 15b, and are provided for the same purpose as the pressing force correction springs 19a and 19b. Is added to the opposite side of the center of gravity Gs, Gs ′ of the insulators 15a, 15b. As will be described later, the spring force of the brake springs 6 a and 6 b also serves as the pressing force correction means 13.

  Next, the operation of the electromagnetic brake device configured as described above will be described.

  For braking, the driving means 8a and 8b are de-energized. For example, if the driving means 8a and 8b are electromagnetic devices 11a and 11b, the electromagnetic force of the electromagnetic coil of the electromagnet 9 is cut off, so that the spring force of the braking springs 6a and 6b is increased. The brake drum 1 is pressed by the braking pieces 4a and 4b via the braking arms 2a and 2b, and the braking state is established. To release the brake, the drive means 8a and 8b are energized. For example, if the drive means 8a and 8b are electromagnetic devices 11a and 11b, the electromagnetic coil of the electromagnet 9 is energized and the spring force of the brake springs 6a and 6b is generated by the electromagnetic attractive force. The levers 15a and 15b are driven against each other, the braking arms 2a and 2b are driven via the connecting members 17a and 17b, and the braking pieces 4a and 4b are separated from the brake drum 1 to release the braking state.

  Next, the spring force of the pressing force correction springs 14a, 14b, 19a and 19b, the weight of the pressing force correction weights 14c, 14d, 19c and 19d and the spring force of the braking springs 6a and 6b will be described. .

The pressing forces PB and PB ′ to the brake drum 1 are expressed by the following equations (11) and (12).

The symbols in the above formulas ( 11 ) and ( 12 ) are as follows.

PB, PB ': Brake drum 1 pressing force of braking pieces 4a, 4b
W _s , W _s ': Weight of braking pieces 4a, 4b
W _gm , W _gm ': Weight of braking arms 2a, 2b
P _m , P _m ′: Pressing force correction spring force of the braking arms 2a, 2b
P _sp , P _sp ': spring force of the braking springs 6a, 6b
W _r , W _r ′: brake springs 6a, 6b and their holding members 7a, 7b weight
W _c , W _c ′: _{Weights of} the connecting members 17a, 17b connecting the braking arms 2a, 2b and the insulators 15a, 15b
W _m , W _m ': Pressure correction weights provided on the braking arms 2a, 2b
W _gs , W _gs ': Weight of the insulators 15a and 15b
P _s , P _s ': Pushing force correction spring force of the insulators 15a, 15b
W _a , W _a ': Weights of movable parts of the driving means 8a, 8b
P _a, P _a ': driving means 8a, tension spring force of 8b
W _n , W _n ′: Pressing force correction weight provided on the insulators 15a, 15b
l ₁ , l ₁ ′: distances from the rotation centers of the braking arms 2a, 2b to the braking pieces 4a, 4b pressing portions
l ₂ , l ₂ ′: distances from the rotation centers of the braking arms 2a, 2b to the connecting members 17a, 17b
l ₃ , l ₃ ′: distances from the rotation centers of the braking arms 2a, 2b to the braking springs 6a, 6b
l _gm , l _gm ': distance from the center of rotation of the braking arms 2a, 2b to the center of gravity of the braking arms 2a, 2b
l _pm , l _pm ′: distances from the center of rotation of the braking arms 2a, 2b to the pressing force correction spring
l _wm , l _wm ': distance from the rotation center of the braking arms 2a, 2b to the pressure compensation weight
l ₄ , l ₄ ′: distances from the rotation centers of the insulators 15a, 15b to the connecting members 17a, 17b
l ₅ , l ₅ ′: distances from the rotation centers of the insulators 15a, 15b to the pressing portions of the electromagnetic devices 11a, 11b
l _gs , l _gs ′: distances from the rotation centers of the insulators 15a and 15b to the center of gravity Gs and Gs ′ of the insulators 15a and 15b
l _ps , l _ps ': distance from the rotation center of the insulators 15a, 15b to the pressing force correction spring
l _wn , l _wn ': Distance from the center of rotation of the insulators 15a, 15b to the pressing force correction weight Note that the symbol without "'" refers to the brake drum 1 upper braking arm 2a, insulator 15a, and the symbol with "'" The present invention relates to the lower braking arm 2b and the lever 15b of the brake drum 1.

(A) Correction method using pressing force correction weights W _m and W _m ′ of the braking arms 2a and 2b
In the equations (11) and (12), the braking springs 6a and 6b forces P _sp and P _sp '= 0, the pressing force correction spring forces P _m and P _m ' = 0 of the braking arms 2a and 2b, the levers 15a and 15b Pressing force correction weight W _n , W _n ′ = 0, pressing force correction spring force P _s , P _s ′ = 0 of the insulators 15a, 15b, braking arm so that the brake drum 1 pressing force PB, PB ′ = 0 The pressing force correction weights W _m and W _m ′ of 2a and 2b are set. That is, the upper braking arm 2a is obtained from the equation (11), and the lower braking arm 2b is obtained from the equation (12).

(B) Correction method using the pressing force correction springs P _m and P _m ′ of the braking arms 2a and 2b Similarly, in the equations (11) and (12), the braking springs 6a and 6b forces P _sp and P _sp ′ = 0, Pressure correction weights W _m , W _m ′ = 0 for the braking arms 2a, 2b, pressure correction weights W _n , W _n ′ = 0 for the levers 15a, 15b, pressure correction spring force P _{s for} the levers 15a, 15b, As P _s ′ = 0, the pressing force correction spring forces P _m , P _m ′ of the braking arms 2a, 2b are set so that the brake drum 1 pressing force PB, PB ′ = 0. That is, the upper braking arm 2a is obtained from the equation (11), and the lower braking arm 2b is obtained from the equation (12).

(C) Correction method using spring forces P _sp and P _sp ′ of braking springs 6a and 6b Similarly, in equations (11) and (12), the pressure correction weights W _m and W _m ′ = 0 of the braking arms 2a and 2b , Pressing force correction spring force P _m , P _m ′ = 0 of the braking arms 2 a, 2 b, pressing force correction weight W _n , W _n ′ = 0 of the levers 15 a, 15 b, pressing force correction spring force P of the levers 15 a, 15 b _Assuming that _s and P _s ′ = 0, the spring forces P _sp and P _sp ′ of the braking springs 6a and 6b are set so that the brake drum 1 pressing force PB and PB ′ = 0. That is, the upper braking arm 2a is obtained from the equation (11), and the lower braking arm 2b is obtained from the equation (12).

In Eqs. (17) and (18), if P _sp , P _sp ′ is positive, it is added to the predetermined spring force, and if P _sp , P _sp ′ is negative, it is subtracted from the predetermined spring force. Will be set.

(D) Correction method using pressing force correction weights W _n and W _n ′ of levers 15a and 15b Similarly, in equations (11) and (12), braking springs 6a and 6b forces P _sp and P _sp ′ = 0, braking Pressure correction spring force P _m , P _m ′ = 0 for arms 2a, 2b, pressure correction weight W _m , W _m ′ for brake arms 2a, 2b, pressure correction spring force P _s , P _{s for} levers 15a, 15b Assuming that “= 0”, the pressing force correction weights W _n , W _n ′ of the levers 15a, 15b are set so that the brake drum 1 pressing force PB, PB ′ = 0. That is, the upper insulator 15a is obtained from the equation (11), and the lower insulator 15b is obtained from the equation (12).

(E) Correction method using the pressing force correction springs P _s and P _s ′ of the insulators 15a and 15b Similarly, in the equations (11) and (12), the braking springs 6a and 6b forces P _sp and P _sp ′ = 0, braking arms 2a, 2b pressing force correction spring force P _m of, P _m '= 0, the braking arms 2a, 2b pressing force correction weight W _m of, W _m', the lever 15a, 15b push force correction weight W _n of, W _n Assuming that “= 0”, the pressure correction spring forces P _s , P _s ”of the levers 15a, 15b are set so that the brake drum 1 pressing force PB, PB ′ = 0. That is, the upper insulator 15a is obtained from the equation (11), and the lower insulator 15b is obtained from the equation (12).

(F) Pressure correction weights W _m and W _m ′ of the braking arms 2a and 2b, pressure correction springs P _m and P _m ′ of the braking arms 2a and 2b, and spring forces P _sp and P _{sp of the} braking springs 6a and 6b ', The pressing force correction weights W _n , W _n ' of the levers 15a, 15b, and the correction methods by a plurality of configurations among the pressing correction springs P _s , P _s ' of the levers 15a, 15b Similarly, the equations (11), (12) Pressure correction weight W _m , W _m ′, pressure correction spring force P _m , P _m ′, brake spring 6a, 6b force P _sp , P The relationship between _sp ′, the pressure correction weights W _n and W _n ′ of the levers 15a and 15b, and the pressure correction springs P _s and P _s ′ of the levers 15a and 15b is expressed by the equations (23) and (24). . That is, the upper braking arm 2a and the upper lever 15a are obtained from the equation (11), and the lower braking arm 2b and the lower lever 15b are obtained from the equation (12).

Therefore, for the upper and lower braking arms 2a and 2b, the pressure correction weights W _m and W _m ′ of the braking arms 2a and 2b on the left side and the braking arms 2a and 2b so that the expressions (23) and (24) are satisfied. Pressure correction springs P _m , P _m ′, spring forces P _sp , P _sp ′ of braking springs 6 a, 6 b, pressure correction weights W _n , W _n ′ of levers 15 a, 15 b, pressure correction springs of levers 15 a, 15 b P _s and P _s ′ may be set respectively.

In addition, when the longitudinal direction of the braking arms 2a and 2b is installed at an angle with respect to the gravity direction between Patent Document 1 and Patent Documents 2 and 3 described in the background art, (1), ( In the equations (2), (11), and (12), the force component in the gravitational direction acts as a pressing force on the brake drum 1 depending on the angle, so the equations (3) to (10) and (13) ) To (24) are the weights of the pressing force correction weights 14c, 14d, 19c and 19d , the spring force of the pressing force correction springs 14a, 14b, 19a and 19b, and the spring force of the braking springs 6a and 6b.

It is a front view of the brake device of a 1st embodiment of the present invention. It is a front view of the brake device of the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake drum 2a, 2b Brake arm 3 Brake surface 4a, 4b Brake piece 6a, 6b Brake spring 8a, 8b Drive means 13, 18 Pressing force correction means 14, 19 External force addition means 14a, 14b, 19a, 19b Pressing pressure correction spring 14c, 14d, 19c, 19d Pressure correction weight 15a, 15b

Claims (4)

Brake pieces disposed on the upper side and the lower side of the brake drum as a braked body, a pair of brake arms that are provided with these brake pieces and are supported in a lateral direction to be pivotally supported, and the brake A brake spring that applies pressure to each of the brake arms so that a piece presses the brake surface and brakes the brake drum, and each brake arm is driven against the spring force of the brake spring to drive the brake Driving means for releasing the pressing of the piece and releasing the braking of the brake drum, and the pressing force to the brake drum is caused by the weight of the mechanism elements such as the braking piece, the braking arm, the braking spring, and the movable part of the driving means. A brake device in which the upper braking arm and the braking piece have an increased pressing force and the lower braking arm and the braking piece have a reduced pressing force with respect to the brake drum pressing force generated by the spring force of the braking spring,
The braking arm is provided with a pressing force correcting means for correcting an unbalance between the increased pressing force and the decreased pressing force of the pressing force of the braking piece to the brake drum, and the pressing force correcting means is an external force provided on the braking arm. Brake device characterized by being an additional means . 2. The brake device according to claim 1, wherein the external force adding means is a pressing force correction weight provided on the braking arm . 2. The brake device according to claim 1, wherein the external force adding means is a pressing force correcting spring provided on the braking arm . A lever is provided between the brake arm and the drive means, and the brake arm is driven by the drive means via the lever, and at least the brake arm is unbalanced in the pressing force to the brake drum. 2. A brake device according to claim 1 , wherein a pressing force correcting means is provided on either of the levers .

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