JP5156200B2 - Drum brake - Google Patents

Abstract

The drum brake has a brake drum (4), two brake shoes (6, 7), and a mechanical retention mechanism (8) for determining the brake position. A motor drive (11) operates the mechanical retention mechanism. The mechanism is a propelled element which is indirectly or directly in contact with the brake shoes to move the position of the brake shoes mechanically.

Description

  The present invention relates to a drum brake equipped with an indwelling device, wherein the indwelling device mechanically secures or locks the brake position or stop position of the drum brake, that is, mechanically holds the vehicle in a stopped state. In other words, it prevents rolling of the stopped vehicle.

  A conventionally known drum brake is operated using a cable. A known duo-servo parking brake, for example as a drum brake, has two brake shoes, both of which are supported by a common corresponding bearing. The brake lining of the brake shoe is mechanically pressed against a brake drum around the brake shoe. Conventionally, this type of drum brake is mechanically operated, for example, via a cable. Such a cable device occupies a relatively large space in the vehicle and is obstructed in the vehicle interior. In this type of brake, it is also known to replace the hand brake lever with a motor unit. In this case, the cable is operated by the motor unit. Accordingly, the driver operates a button or a switch, and as a result, the motor unit is activated to stop the vehicle. This type of parking brake is also called a cable tension mechanism brake.

  In order to improve the drum brake of the conventional structure of the above-mentioned type, in the present invention, the drum brake is a mechanical locking device for locking the brake position or the stop position (holding the brake action), the drive unit, and the driveable In this case, the driving member is driven by the driving unit, and the driving member can be driven indirectly or directly by the brake shoe of the drum brake. As a result, the parking brake position (braking condition) of the brake shoe is mechanically locked, i.e. held. As a result of such an arrangement according to the invention, the conventionally required cables or the like are omitted, and the drum brake is particularly robust and space-saving.

  Advantageous embodiments of the invention are described in the dependent claims.

  It is advantageous if a transmission device is arranged between the drive part and the driveable component of the locking device or locking device. Particularly preferably, the transmission is arranged in the brake drum. More preferably, the drive part is arranged perpendicularly to the rear plate (back plate) or cover plate of the drum brake. In particular, a space-saving structure can be achieved. In order to omit additional securing members or locking members, the transmission is configured to produce a self-locking action. This is accomplished by forming a self-locking mechanism or a self-locking mechanism between two gearing members that are engaged with each other.

  In an advantageous embodiment of the invention, the brake shoe is adapted to be pressed or pressed against the brake drum using fluid pressure, in particular using hydraulic pressure. As a result, it is possible to form a drum brake having a very strong structure that can be used as a normal driving brake and a parking brake.

  Advantageously, the drivable component of the locking device comprises a cam member, the cam member having a first cam and a second cam. The first cam is in contact with the first brake shoe indirectly or directly for mechanical locking of the parking brake position during rotation of the cam member, and the second cam is Indirect or direct contact with the second brake shoe.

  It is advantageous if a planetary gear device is arranged between the cam member and the drive part. The cam member is particularly preferably formed by a ring gear or an internal gear of a planetary gear set.

  In order to obtain a defined start end position (starting position or starting position) or end position of the cam member, at least one stopper for limiting the rotation of the cam member is provided. This ensures that the cam member is always returned to the defined starting position.

  In a further advantageous embodiment of the invention, the locking device is formed by a spindle device having one double spindle. The double spindle comprises a first screw and a second screw, in which case both screws are constructed in opposite directions. The first screw of the double spindle, for example a male screw, engages with the first movable member or floating bearing member, and more particularly, the first movable member or the floating bearing member engages with a screw, such as a female screw. The second screw of the double spindle, for example the male screw, engages the second movable member or floating bearing member, more particularly the second movable member or floating bearing member. Engaging with, i.e., meshing with, an external thread. The movable member (floating support member) means a component member that is supported so as to be freely movable in a floating manner. Based on the engagement of the double spindle and both movable members, both movable members are moved in opposite directions upon rotation of the double spindle. Such movement can achieve a reliable closing or opening of the indwelling device or the parking brake.

  In order to achieve a particularly sturdy and inexpensive structure, the movable member is formed as a brake piece (a brake shoe operating member) of the drum brake. As a result, the number of components can be reduced. A first screw of the double spindle, for example a male screw, is engaged with a screw of a first brake piece, for example a female screw, and a second screw of the double spindle, for example a male screw, is a second brake piece, for example, a female screw. Is engaged.

  In another advantageous embodiment of the invention, the locking device is formed by a spindle device having one spindle (threaded shaft) and one movable member. When the driving unit is operated, the spindle generates a locking force on one brake shoe, and the movable member generates a locking force on the other brake shoe. A particularly simple structure of the locking device can be obtained by forming the locking device with one single spindle (the only threaded shaft).

  The locking device formed with a single spindle preferably has one first gear and one second gear, both gears being formed by a spur, ie a spur gear or It is formed as a spur gear. In this case, the second gear is formed as a movable member provided on the spindle or coupled to the movable member, and the tooth widths of both gears are different from each other. Accordingly, when the locking device or the brake piece, and hence the brake shoe, is moved to the locking position (tightening position) or returned to the locking release position (starting position or tightening release position), the second gear is moved to the first gear. It can be moved or moved in the axial direction relative to the gear.

  In another embodiment of the present invention, the locking device has a oscillating disk type transmission device, and the oscillating disk type transmission device includes a first operating member for pressing the brake shoe against the brake drum ( Brake piece) and the second operating member (brake piece) and the drive unit. By using the oscillating disk type transmission device, a compact structure can be obtained with a large gear ratio.

  In yet another embodiment of the invention, the locking device is formed by a lever device with one lever, the first end of the lever is connected to the drive and the second of the lever The end portion is supported so as to be able to turn around one turning point. The lever is indirectly or directly connected to the first brake shoe and the second brake shoe. When the drive unit is operated, the lever is pivoted about the pivot point to generate a locking force or a tightening force on the first brake shoe and the second brake shoe. In an advantageous embodiment, the lever contacts (couples) one brake piece between the first end and the second end or pivot point, and via an intermediate member at the second end, That is, it is indirectly contacted (connected) to the other brake piece.

  The lever device preferably further comprises a spindle, which is engaged with one end of the lever. The spindle is coupled to the drive and is adapted to rotate upon actuation of the drive so that the one end of the lever is moved in the axial direction of the spindle so that the lever is pivoted. The pivot point is not fixedly arranged, i.e. not a fixed point, so that it is displaced or moved depending on the movement of the one end of the lever. The engagement between the spindle and one end of the lever is performed using a nut-like member, and the nut-like member is screwed onto the spindle and is supported on the one end of the lever. ing.

  Further advantageously, the lever device is provided with a mechanical adjusting means or adjusting device, for example for compensation of changes in the working stroke distance due to wear of the locking device or for compensation (post-adjustment) in the event of wear of the brake lining. Have. In this case, the mechanical adjusting means or adjusting device is supported on the pivot point of the lever at one end and is in contact with the brake shoe indirectly or directly at the other end.

  The locking device is preferably supported in a floating manner between the brake shoes. This guarantees equal braking action or braking force for both brake shoes. That is, the braking action or braking force of both brake shoes is balanced.

  In a locking device formed with a spindle, the operating stroke is made longer, i.e. provided with an operating stroke longer than that required for a rough locking function, so as to compensate for stroke distance variations due to wear. It is also possible to make it. By such means, an adjusting device for wear compensation (post-adjustment) can be omitted.

  The drive of the locking device according to the invention is preferably an electric motor, and in this case it is advantageous if a current limit value detection device and / or a torque limit value detection device is provided in order to avoid damage to the electric motor. It is. The measurement value detected by the current limit value detection device and / or the torque limit value detection device is also used for diagnosis of the indwelling device or the parking brake in relation to the locked state. The current limit value detection device and / or the torque limit value detection device is configured to shut off the electric motor when detecting a predetermined threshold value or a maximum allowable value, for example.

  The brake provided with the locking device according to the present invention is used in various automobiles, in particular, high-class automobiles or light trucks, sports cars, and the like.

  A drum brake 1 schematically shown in FIG. 1 has a parking brake function according to the present invention which is different from a conventional type, that is, different from a cable operation type. The drum brake 1 includes a first brake shoe 2 and a second brake shoe 3. The brake shoes 2 and 3 are provided with a brake lining 5 in a known manner. The brake lining 5 is pressed against the inner periphery of the brake drum 4 by the radial movement of the brake shoes 2 and 3. The brake shoes 2, 3 are arranged symmetrically with each other in the brake drum 4 and are connected to each other via an adjusting device 9 at the first end. The adjusting device 9 is not an essential component and may be omitted. A locking device 8 is arranged according to the invention between the other ends of both brake shoes 2,3. As shown in FIG. 1, the locking device 8 is disposed between the first brake piece 6 and the second brake piece 7. The locking device 8 is advantageously driven by an electric motor, which is arranged on the cover plate of the drum brake 1 perpendicular to the plane of FIG. In addition, the drive may be arranged inside the brake shoes 2, 3 in order to enable a particularly compact structure. A brake shoe pull-back spring (return spring) denoted by reference numeral 10 in FIG. 1 assists the return of the drum brake to the starting position shown in FIG.

  Next, based on FIG.2 and FIG.3, the latching device 8 for the drum brake of the 1st Example of this invention is demonstrated. The locking device 8 has an electric motor as the drive unit 11. The electric motor is configured to drive the output shaft 20, and the output shaft is coupled to the first worm gear 21. The first worm gear 21 meshes with the inclined gear 22, and the gear (worm wheel) drives the coupling shaft 23. A sun gear 24 of a planetary gear mechanism (planetary gear device) is disposed on the coupling shaft 23. The sun gear 24 meshes with the three planetary gears 25, and the planetary gear meshes with the ring gear 26. As shown in FIG. 3, the ring gear 26 is formed as a cam member (cam element) including a first cam 27 and a second cam 28. In this case, the outer periphery of the ring gear 26 is in contact with the first brake piece 6 and the second brake piece 7 that are disposed facing each other toward the ring gear 26.

  When the drive unit 11 is operated, the rotation of the output shaft 20 is transmitted to the sun gear 24 via the worm gear device and to the ring gear 26 via the planetary gear mechanism. As a result, the ring gear 26 is rotated about its central axis, and as a result, the first brake piece 6 and the second brake piece 7 are moved outward in the directions of arrows B and C. Since the first brake piece 6 and the second brake piece 7 are brought into contact with the brake shoes 2 and 3, respectively, the brake lining is pressed against the brake drum by the movement of the brake pieces 6 and 7. In order to enable as simple a movement as possible of the brake pieces 6, 7, the brake pieces are each supported on a bearing 29. In addition, either the planetary gear mechanism component or the worm gear device component is formed as a self-locking (self-locking) transmission, and the parking brake automatically reverses (self-relaxing or Automatic return) is prevented. When the brake lining is pressed against the brake drum, the electric motor is shut off. The parking brake position is mechanically locked or locked by a self-locking (non-reversible) transmission. The electric motor may be shut off (switched off) by, for example, a signal, and the signal may be detected by a current detection sensor or a moment detection sensor.

  As is apparent from FIG. 3, the cam member is rotated by 90 ° at the maximum. In addition, it is preferable that the maximum rotation angle of the cam member be smaller than 90 ° for reasons of operational reliability or safety. As a result, the rotation (rotation) of the cam member exceeding 90 °, and hence the reduction of the braking force can be prevented. For this purpose, for example, another sensor for monitoring the movement of the cam member or a stopper for defining the end position of the rotation of the cam member may be provided. It is also possible to carry out a rationality check for lining wear based on a diagram relating to the distance (rotation angle) and force (electric power) when the ring gear 26 rotates. For example, if the rotation angle of the ring gear 26 exceeds a predetermined value, this is an indication for excessive lining wear, such indication being given to the driver, for example by an alarm device.

  In order to release (release) the parking brake, the drive unit 11 is simply operated in the reverse direction. The rotational motion of the output shaft 20 in this case is transmitted to the ring gear 26 through the worm gear device and the planetary gear mechanism, and as a result, the ring gear is rotated in the reverse direction.

  A second embodiment of the present invention will be described with reference to FIG. The same or functionally the same parts are denoted by the same reference numerals as in the first embodiment. The second embodiment is substantially similar to the first embodiment. The driving torque is transmitted to the ring gear 30 via the sun gear 24 or the planetary gear 25. Similarly, the ring gear 30 has a first cam 31 and a second cam 32. As shown in FIG. 4, the cams 31 and 32 have an appropriate inclined surface (cam surface) only on one side. Have. Step portions 33 and 34 are formed on the other side, and the step portions are in contact with the stoppers 35 and 36 at the starting position (starting position) shown in FIG. As an advantage in this embodiment, the cams 31 and 32 are accurately returned to the starting position, that is, rotated back, by bringing the step portions into contact with the stoppers 35 and 36. As a result, the locking device always occupies the defined zero point position (starting position) when the parking brake is released (brake release).

  Next, a third embodiment of the present invention will be described with reference to FIG. The same or functionally identical parts are given the same reference numerals as in the previous embodiments. As shown in FIG. 5, the locking device 8 of the third embodiment has an electric motor type drive unit 11 and worm gear devices 21 and 22. In this case, the bevel gear 22 of the worm gear device is coupled to the first gear 46 via the shaft 23. The first gear 46 has teeth that are cut parallel to the axis, that is, a right gear, and has a predetermined tooth width a. The first gear 46 is in mesh with the second gear 41, and the second gear has a predetermined tooth width b. In this case, the tooth width a of the first gear 46 is smaller than the tooth width b of the second gear 41. The second immediate gear 41 is rigidly connected to the sleeve 42, i.e. immovably (relatively immovable), and the sleeve has an axial line (longitudinal direction) of the first brake piece 6 or the second brake piece 7. It is supported in the support part 43 toward the movement direction. The sleeve 42 has an internal thread and is a component part of the spindle device, ie the spindle device is formed by the sleeve 42 and the spindle 44. The sleeve 42 is screwed onto the spindle 44. In this case, the spindle 44 is prevented from rotating or rotating. The second brake piece 7 is arranged on the head 44 a of the spindle 44, and the first brake piece 6 is in contact with the second gear 41. In this case, the entire structure including the brake pieces 6 and 7, the spindle 44, the sleeve 42 and the second gear 41 is supported in a floating manner, that is, freely movable left and right as viewed in the drawing.

  When the parking brake is to be moved to the braking position, that is, the closed position, when the driving unit 11 made of an electric motor is operated, the torque of the driving unit is changed to the second through the worm gear devices 21 and 22 and the first gear 46. The gear 41 is transmitted. Since the sleeve 42 is firmly connected to the second gear 41, the sleeve rotates. Since the spindle 44 is not rotated, the sleeve 42 moves along the spindle 44. As a result, the first brake piece 6 and the second brake piece 7 are moved outward in the directions of arrows B and C, that is, in directions away from each other. In this case, both brake shoes 2 and 3 are moved. It is uniformly loaded or pressed on the operating part of the brake shoe, i.e. the floating bearing of the entire configuration. In order to prevent return movement by one of the spindle devices, the spindle device is designed to be self-locking, i.e. to produce a self-locking action. When the brake lining is pressure-bonded to the brake drum by rotating the sleeve 42 around the axis of the spindle 44, the parking position (detained state) is locked (locked) based on the self-locking action (self-locking action) of the spindle device. . In order to release the parking position, i.e. to release the parking brake, it is only necessary to actuate the drive 11 in the opposite direction, whereby the sleeve 42 is also moved on the spindle 44 in the opposite direction. As a result, the brake pieces 6 and 7 are also returned to the starting position. It is also possible to provide a terminal stopper on the spindle 44 or the sleeve 42, so that the locking mechanism 8 can be accurately returned to a predetermined position.

  FIG. 6 shows a drum brake according to a fourth embodiment of the present invention. In this case, the same reference numerals as those in the above-described embodiment are attached to the same or functionally same portions. The fourth embodiment is similar to the third embodiment of FIG. The electric motor type drive unit 11 has the worm gear devices 21 and 22 connected to the first gear 50. The first gear 50 meshes with the second immediate gear 51. In this case, the tooth width a of the first gear 50 is larger than the tooth width b of the second gear 51. The second gear 51 is firmly connected to the double spindle 52 of the spindle device. As shown in FIG. 6, the double spindle 52 is one shaft member that protrudes from both sides of the gear 51. In this case, the double spindle 52 includes a first screw 53 and a second screw 54 to form a feed shaft. The first screw 53 and the second screw 54 are configured in opposite directions. The first screw 53 engages with a female screw 57 provided in a recessed portion (notch) inside the first brake piece 6, that is, is screwed into the female screw 57. The screw 54 is engaged with a female screw 58 provided in a recessed portion inside the second brake piece 7, and the brake pieces 6 and 7 constitute a component part of the spindle device. In this case, the brake pieces 6 and 7 are supported by the support portions 55 and 56 and are slid in the axial direction, that is, in the directions of arrows B and C. With this configuration, the number of parts can be reduced, and a sturdy structure of the locking device 8 can be achieved. The brake pieces 6 and 7 are prevented from rotating by, for example, spline engagement or sliding key type guidance. Also in this case, the screw between the double spindle 52 and the brake pieces 6 and 7 is configured to cause a self-locking action. The entire spindle device including the second gear 51 is also supported in a floating manner, so that different wear on both brake linings can be compensated. In this case, the second gear 51 moves in the axial direction relative to the first gear 50.

  When the drive unit 11 is operated to lock the parking brake, torque is transmitted to the double spindle 52 via the worm gear unit and the gears 50 and 51. As a result, the brake pieces 6 and 7 move outward in the direction of the arrow to mechanically lock the parking brake. In order to release the parking brake, the drive unit 11 is actuated in the reverse direction, and as a result, the brake pieces 6 and 7 are returned. In addition, the bottom surface of the recessed portion inside the brake pieces 6 and 7 may be used as a stopper. It is also possible to provide a separate stopper. By providing a stopper, a defined starting position can be achieved, and the locking device 8 can be returned to the starting position without problems.

  FIG. 7 shows a drum brake according to a fifth embodiment of the present invention. In this case, the same reference numerals as those in the above-described embodiment are attached to the same or functionally same portions. As in the previous embodiment, the torque of the motor-type drive unit 11 is transmitted via the first worm gear 21 and the inclined gear 22. In this case, the inclined gear 22 additionally has a tooth portion 61 arranged on the outer circumferential portion of the end face, and the second worm gear 22 is swung by the tooth portion (dentition). The moving disk 60 is engaged. As shown in FIG. 7, the swing disk 60 is disposed at a predetermined angle with respect to the second worm gear 22. Another tooth portion 62 is formed on the side surface of the oscillating disk 60 opposite to the second worm gear 22, whereby the oscillating disk 60 is engaged with the tooth portion of the disk 63. The disk 63 is rigidly coupled to the shaft 64 and is provided with a spindle screw 65 at the other end of the shaft 64. As shown in FIG. 7, the shaft 64 is guided through the oscillating disk 60 and the second worm gear 22.

  The oscillating disk 60 is supported on the component 67. The component 67 has a holding device 67a, and supports the outer peripheral portion of the oscillating disk 60 by the holding device. The holding device 67 may be formed by, for example, a plurality of holding arms, or may be formed in a pot shape or a cup shape. The holding device 67a is coupled to the plate 67b and the shaft 67c. The component 67 is particularly preferably formed in one piece. A spiral screw 68 is provided on the shaft 67c. As shown in FIG. 7, a support portion 66 is disposed between the plate 67 b of the component 67 and the disk 63. The screw 68 is engaged with the female screw of the second brake piece 7, and the screw 69 of the shaft 64 is engaged with the female screw of the first brake piece 6. Also in this case, the bottom region of the brake pieces 6 and 7 may be formed as a stopper.

  The locking device 8 of the fifth embodiment functions as follows. That is, when it is desired to mechanically lock the parking brake position, when the drive unit 11 is operated, the torque of the drive unit is transmitted to the inclined gear 22 via the first worm gear 21. The second worm gear 22 drives the oscillating disk 60 via the tooth portion 61. The oscillating disk 60 drives the disk 63 via the teeth 62, so that the shaft 64 rotates with the disk 63. Since the first brake piece 6 is supported so as not to rotate, the brake piece moves in the direction of arrow C along the screw 65 to operate the first brake shoe 2. Further, the rotating rocking disc 60 also drives the shaft 67d via the holding device 67a and the plate 67b. As a result, the brake piece 7 is moved in the direction of the arrow B, and as a result, the second brake shoe 3 is operated. The thread between the brake pieces 6 and 7 and the shafts 67c and 64 is configured to cause a self-locking action in order to prevent the parking device, that is, the parking brake alone from returning. In order to release the parking brake, i.e. to return it to the intended position, it is only necessary to actuate the drive unit 11 in the reverse direction. Returned. The advantage of the locking device 8 using the oscillating disk 60 is that a large transmission can be achieved by the oscillating disk. In this embodiment, the drive unit 11 is similarly mounted vertically on the cover plate of the drum brake, and the entire locking device can be arranged in the drum brake.

  FIG. 8 shows a sixth embodiment of the present invention. In this case as well, the same portions or functionally the same portions are denoted by the same reference numerals as in the previous embodiments. As shown in FIG. 8, the locking device 8 is formed by a lever mechanism. In this case, the lever mechanism is arranged between the first brake piece 6 and the second brake piece 7. The brake pieces 6 and 7 are moved in the directions of arrows B and C so as to be separated from each other along the axis XX for locking.

  The lever mechanism has a lever 73 supported at the turning point D. The lever 73 has a movable member 72, which may be formed as a nut-like member, for example, is engaged with the screw 71 of the spindle 70 and is attached to one end of the lever. Is retained. The spindle 70 is driven by an electric motor type drive unit 11. On the lever 73, more precisely, another intermediate member 74 is arranged at the turning point D, and this intermediate member is provided with an adjusting device 75. The spring 76 is disposed between the lever 73 and the intermediate member 74 to assist the return movement of the lever mechanism to the starting position. As shown in FIG. 8, the first brake piece 6 is disposed at the end of the intermediate member 74 on the side opposite to the lever 73. The second brake piece 7 is arranged on the lever 73 directly in the vicinity of the turning point D and on the upper side of the turning point D.

  When the electric motor type drive unit 11 is operated to mechanically lock the parking brake position, the drive unit rotates the spindle 70. As a result, the lever 73 is moved in the direction of arrow A along the screw 71 of the spindle 70. In this case, the lever 73 performs a turning motion around the turning point D of the lever. In other words, the lever 73 itself moves toward the second brake piece 7 and additionally turns around the turning point D, whereby the intermediate member 74 is moved toward the first brake piece 6. . That is, the brake pieces 6 and 7 are moved in directions opposite to each other, whereby the parking brake position is mechanically locked. In addition, the turning point D is not a fixed point but is moved depending on the position of the movable member 72 on the spindle 70. In this case, the screw between the spindle 70 and the movable member 72 is formed so as to produce a self-locking action, and as a result, the return by itself is avoided. Due to the configuration of the lever mechanism according to the present invention, the pivoting movement of the lever mechanism prevents an excessive lateral force from acting on the spindle 70. As a result, spindle damage is avoided and reliable operation is guaranteed. The device according to the invention has a minimal number of components and is a sturdy structure. Furthermore, the wear of the brake lining can be compensated by a large movement distance of the movable member 72 along the spindle 70 or by adjustment in the adjusting device 75. In addition, an end stopper can be provided to return the locking device 8 to the specified end position.

  In the sixth embodiment, the parking brake position is released by operating the drive unit 11 in the reverse direction. As a result, the movable member 72 is moved in the reverse direction along the spindle 70. In this case, the intermediate member 74 is returned by the spring 76. As a modification, it is also possible to arrange a transmission device between the drive unit 11 and the spindle 70.

  In all the above-described embodiments, as an additional means, using the current consumption and / or torque of the drive unit 1, detection detection of a locked position or detection of arrival at a predetermined position is performed. It may be. This is done using a diagnostic device.

  In all embodiments, the parking brake position may be achieved purely mechanically and locked. In another possible variant, the drum brake is moved by fluid means, for example hydraulically or pneumatically, to the braking position or the parking brake position, and the locking device produces a mechanical locking function exclusively. It may be squeezed. The parking brake function may be combined with an existing brake control device of the vehicle, such as an electronically controlled brake system or an anti-lock brake system.

Schematic of a drum brake having a parking brake function according to the present invention Schematic sectional view of a first embodiment of a locking device according to the present invention Schematic plan view of the locking device shown in FIG. Schematic plan view of a second embodiment of a locking device according to the present invention Schematic plan view of a third embodiment of a locking device according to the invention Schematic plan view of a fourth embodiment of a locking device according to the present invention Schematic plan view of a fifth embodiment of a locking device according to the present invention Schematic plan view of a sixth embodiment of a locking device according to the present invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Drum brake, 2,3 Brake shoe, 4 Brake drum, 5 Brake lining, 6,7 Brake piece, 8 Locking device, 9 Adjustment device, 10 Brake shoe retracting spring, 11 Drive part, 20 Output shaft, 21 Worm gear , 22 gear, 23 coupling shaft, 24 sun gear, 25 planetary gear, 26 ring gear, 27, 28 cam, 30 ring gear, 31, 32 cam, 33, 34 step, 35, 36 stopper, 41 gear, 42 sleeve, 43 support Part, 44 spindle, 46 gear, 53, 54 screw, 55, 56 bearing part, 60 swinging disk, 70 spindle, 71 screw, 72 movable member, 73 lever, 74 intermediate member, 75 adjusting device, 76 spring

Claims (20)

A drum brake having a parking brake function for placing a vehicle, wherein the brake drum (4), the first and second at least one brake shoes, and a mechanical lock for locking the parking brake position device (8), and wherein comprises driving moving parts for operation of the mechanical locking device (8) to (11), a mechanical locking device (8) has a drivable component The component is in direct or indirect contact with the first and second brake shoes (2, 3), whereby the first and second brake shoes (2, 3). ) Is mechanically locked , and a transmission device (21, 22; 24, 25, 26) is disposed between the drive portion (11) and a driveable component of the locking device. Yes and, said transmission kinematic system is configured to give rise to self-locking action Drum brake characterized by Rukoto. 2. The drum brake according to claim 1, wherein the first and second brake shoes (2, 3) are pressed against the brake drum (4) by means of a fluid operating device, in particular a hydraulic operating device. . A cam member (26) is provided as a driveable component of the locking device. The cam member has a first cam (27) and a second cam (28), and the cam member (26 ), The first cam (27) locks the first brake shoe (2), and the second cam (28) locks the second brake shoe (3). The drum brake according to claim 1 or 2 . 4. The drum brake according to claim 3 , wherein planetary gear devices (24, 25) are arranged between the cam member (26) and the drive section (11). 5. A drum brake according to claim 4 , wherein the cam member is formed by a ring gear of a planetary gear device. The drum brake according to any one of claims 3 to 5 , wherein the cam member (30) has at least one stopper (35, 36) for limiting the rotation of the cam member (30). The locking device (8) is formed by a spindle device, which has a single double spindle (52), which double spindle (52) has a first screw (53) and a second screw. and a screw (54), said first screw (53) and said second screw (4) and drum brake according to claim 1 or 2 is configured in opposite directions. The first screw (53) is engaged with the screw of the first brake piece (6), and the second screw (54) is engaged with the screw of the second brake piece (7). Item 8. The drum brake according to item 7 . The double spindle (52) is connected to a quick gear (51), which is in the axial direction of the double spindle (52) relative to the first quick gear (50). 9. A drum brake according to claim 7 or 8 , wherein the drum brake is adapted to move. The locking device (8) is formed by a spindle device, and the spindle device has one spindle (44) and a movable member (42), and the movable member (42) has a locking force. 3. The first brake shoe (2) according to claim 1 or 2 , wherein the spindle (44) is adapted to generate a locking force on the second brake shoe (3). Drum brake as described. The locking device (8) further comprises a first gear (40) and a second gear (41), the second gear (41) being a spindle device. 11. The drum brake according to claim 10 , wherein the drum brake is formed as a movable member, or is rigidly connected to a sleeve-like movable member (42). The locking device (8) has an oscillating disk type transmission device, and the oscillating disk type transmission device is disposed between the first brake piece (6) and the second brake piece (7). The drum brake according to claim 1 or 2 . The locking device (8) has a lever device, the lever device comprises one lever (73), the first end of the lever is connected to the drive part (11), The second end of the lever (73) is supported at one turning point (D), and the lever (73) is turned around the turning point (D) when the drive unit is operated. The drum brake according to claim 1 or 2 , wherein the turning point (D) is displaced during the turning movement of the lever (73). 14. A drum brake according to claim 13 , wherein the lever device has a spindle (70), which is engaged with a movable member (72) provided on the lever (73). The lever device has an intermediate member (74) which is arranged between one brake piece (6) and the pivot point (D), and the lever (73) is another brake piece. The drum brake according to claim 13 or 14 , which is in contact with (7). 16. A drum brake according to any one of claims 13 to 15 , wherein the intermediate member (74) has a mechanical adjustment device (75). Drum brake according to any one of claims 1, which is supported on floating 16 between the locking device (8) is first brake shoe (2) and the second brake shoe (3) . The drum brake according to any one of claims 1 to 17 , wherein the drive section (11) is formed by an electric motor. The electric motor has a current limit value detecting device and / or a torque limit value detecting device, and the current limit value detecting device and / or the torque limit value detecting device cuts off the electric motor at a predetermined threshold value. The drum brake according to claim 18 . The drum brake according to claim 18 or 19 , further comprising a diagnostic device, wherein the diagnostic device determines a state of the locking device based on a characteristic value of the electric motor.

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