JP4053017B2 - Parking brake device for drum brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an automatic parking brake condition by a simple structure involving no electric power consumption. <P>SOLUTION: The parking brake condition is obtained by advancing operation of a parking piston 33 in response to action of control hydraulic pressure for parking, and the advancing condition of the parking piston 33 is mechanically locked by a lock mechanism 43. In addition, a lock piston 44 constituting part of the lock mechanism 43 is operated in one side in the axial direction during the advancing operation of the parking piston 33 and rotatably fitted to a casing 26. A lock part 46 having an engagement face 46a which is engaged with a locking part 45 provided in a stopper 36 connected with the parking piston 33 and which mechanically locks the advancing operation position of the parking piston 33 is provided in one end part in the axial direction of the lock piston 44. The engagement face 46a is formed by being inclined so as to be in the axial direction backward position of the parking piston 33 toward one side in the axial direction of the lock piston 44. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

The present invention relates to a parking brake device for a drum brake , and more particularly to a parking brake device for a drum brake that obtains a parking brake state by the action of hydraulic pressure.

A parking brake device that obtains a parking brake state by the action of such hydraulic pressure is already known, for example, in Patent Document 1 and Patent Document 2.
Japanese National Patent Publication No. 10-512947 JP 2000-504811 A

  By the way, in the said patent document 1, while a brake piston is divided | segmented into a front part and a rear brake piston, between the transmission member contact | abutted to the front end of a rear brake piston, and the obstruction board fixed to a front brake piston. A latch that can be engaged with an internal tooth engraved on the inner surface of the brake caliper behind the front brake piston with a spring contracted is engaged with the internal tooth when the transmission member is in contact with the front end of the rear brake piston. However, when the transmission member moves relatively forward from the front end of the rear brake piston, it is housed in the brake caliper so as to be disengaged from the internal teeth by a spring biasing force, An auxiliary piston that can move the member in the axial direction relative to the rear brake piston is slidably fitted. However, internal teeth must be engraved on the inner surface of the brake caliper, and the latch is housed in the brake caliper while dividing the brake piston into the front and rear brake pistons. It becomes complicated.

  Further, in Patent Document 2, an adjustment nut is screwed onto an adjustment bolt whose front end is fixedly connected to a brake piston, and an electromagnet that exerts electromagnetic force that frictionally engages the adjustment nut with a casing is provided on the adjustment nut. The brake caliper is arranged behind the brake caliper. When the parking brake state is obtained, the brake piston is moved backward by frictionally engaging the adjusting nut with the casing by the electromagnet while the brake fluid pressure is applied to the brake piston. I try to prevent it. However, it is necessary to store the electromagnet in the brake caliper, which not only complicates the structure, but also requires that the energization state of the windings of the electromagnet be maintained in the parking brake state, resulting in an increase in power consumption.

The present invention has been made in view of such circumstances, and an object thereof is to provide a parking brake device for a drum brake that can obtain a parking brake state with a simple structure that does not involve power consumption.

In order to achieve the above object, the present invention provides a casing fixed to a drum brake back plate and a parking brake operating lever connected to a drum brake via a connecting means, and a control hydraulic pressure for parking on the rear side. a parking piston slidably fitted into the casing as possible to obtain a parking brake state of the drum brake by the forward operation according to the action of the parking in order to mechanically lock the parking piston at a forward position A lock operation is automatically performed by a temporary action of the parking release control hydraulic pressure corresponding to the forward movement of the piston and a subsequent release thereof, and a lock release action is performed in accordance with the action of the parking release control hydraulic pressure. Lock mechanism provided in casing, hydraulic pressure generation source, and generation of the hydraulic pressure generation source And a possible and the fluid pressure control means that controls the pressure to obtain the parking control fluid pressure and the parking release control fluid pressure, said coupling means includes a rod which is connected to the rear end of the parking piston A stopper connected to the rod and a connecting rod connecting the stopper and the parking operation lever, and the locking mechanism is acted on by an urging force in one axial direction at least when the parking piston moves forward. The lock piston having an axis perpendicular to the axis of the parking piston while being slidably fitted to the casing and allowing the parking release control pressure to act in the other axial direction When a locking portion provided before kissing top path, advancing operation of the parking piston engages from behind the locking portion The parking piston as located mechanically and a lock portion provided at one axial end portion of the front Symbol lock piston has an engagement surface that locks the engaging surface is directed in one axial direction of the locking piston It is formed so as to be inclined so as to be a rearward position in the axial direction.

According to the present invention, when the parking control hydraulic pressure is applied to the back side of the parking piston, the parking piston moves forward, and the temporary operation of the parking release control hydraulic pressure according to the forward operation of the parking piston and thereafter Since the lock mechanism mechanically locks the advance position of the parking piston by releasing the parking brake state, the parking brake state can be obtained automatically, and when releasing the parking brake state, the parking release control hydraulic pressure is applied to the lock mechanism. The parking brake state can be automatically obtained with a simple structure that does not involve power consumption in the parking brake state.

The connecting means includes a rod connected to the rear end of the parking piston, a stopper connected to the rod, and a connecting rod connecting the stopper and the parking operation lever. The locking mechanism includes at least the parking piston. When the forward movement of the actuator is performed, an urging force directed in one axial direction is applied, and an axis perpendicular to the axis of the parking piston is slidably fitted to the casing and a control pressure for releasing the parking is applied. a lock piston that allows exerting toward the other axial, and the locking portion provided in front kiss stopper, mechanical advancement operating position of the parking piston engages from behind the locking portion A locking portion provided at one end in the axial direction of the locking piston. Since the parking piston is inclined so as to be in the rearward position in the axial direction of the parking piston, the parking piston moves forward in response to the change in the forward movement amount from the retracting limit of the parking piston in the parking brake state. The operating position can be mechanically locked, and it is possible to cope with a change in stroke amount of the parking piston in accordance with wear of the friction member for obtaining a dimensional tolerance, an assembly error, or a brake state. In addition, the stopper provided with the locking portion is arranged in the middle of the connecting means connecting the parking piston and the parking operation lever, so that the forward operating force of the parking piston is connected to the parking operation lever of the drum brake. In addition, the lock mechanism can be made compact and simplified.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 9 show an embodiment of the present invention, FIG. 1 is a front view of a drum brake, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a line 3-3 of FIG. FIG. 4 is a perspective view of the stopper and the lock piston, FIG. 6 is a diagram showing the configuration of the hydraulic circuit, and FIG. 7 corresponds to FIG. 2 in the parking brake state. 8 is a cross-sectional view taken along line 8-8 in FIG. 7, and FIG. 9 is a cross-sectional view taken along line 9-9 in FIG.

  First, in FIG. 1, a back plate 12 provided in a drum brake 11 dedicated to a parking brake is fixedly attached to the vehicle body side so as to cover an open end of a brake drum (not shown). One end of a pair of brake shoes 13, 13 having linings 14, 14 slidably contacting the brake drum and disposed in the brake drum is swingably supported on both ends of a strut 15 that can be expanded and contracted. Between the one ends of the shoes 13..., Springs 16 for urging the brake shoes 13. The other ends of the brake shoes 13 are detachably supported by an anchor 17 provided on the back plate 12 and are urged toward a side supported by the anchor 17 by a return spring 18. Further, notches 19 are respectively provided on the opposite surfaces of the brake shoes 13 on the other end side, and both ends of the strut 21 are engaged with the notches 19 so that one end of the strut 21 and one brake shoe are engaged. A spring 22 is contracted between 13.

  A parking operation lever 23 is disposed between the brake shoe 13 and the back plate 12 so as to partially overlap one of the brake shoes 13, and a parking drive means 25 is connected to one end of the operation lever 23. The other end portion of the parking operation lever 23 is engaged with one end of the strut 21 and is pivotably connected to the other end portion of the one brake shoe 13 via a pivot 24.

  Thus, when the parking operation lever 23 is rotated around the pivot 24 in the clockwise direction in FIG. 1 by the parking drive means 25, the other brake shoe 13 is pressed against the inner periphery of the brake drum via the strut 21. Due to the reaction, one brake shoe 13 is also pressed against the inner periphery of the brake drum, whereby a parking brake state by the drum brake 11 can be obtained.

  2 and 3 together, the parking drive means 25 includes a casing 26 fixed to the back plate 12 on one end side of the brake shoes 13. The casing 26 is integrally connected to a first tube portion 26a extending in a direction parallel to the struts 15 and the spring 16, and an intermediate portion of the first tube portion 26a extending in a direction orthogonal to the first tube portion 26a. The second cylinder part 26b is disposed on the inner surface side of the back plate 12, and the second cylinder part 26b extends outward through the back plate 12.

  A partition wall 27 is integrally provided at an axially intermediate portion of the first tube portion 26a with both ends open, and a first sliding hole is formed in the first tube portion 26a on the front side (upper side in FIG. 3) of the partition wall 27. 28, and a guide hole 29 coaxial with the first sliding hole 28 is provided in the first cylindrical portion 26a on the rear side (lower side in FIG. 3) of the partition wall 27. A lid member 30 that closes the front end is screwed into the first tube portion 26a.

  The second cylindrical portion 26 b is provided with a second sliding hole 31 that is continuous to the guide hole 29 at a right angle. The second sliding hole 31 has a small-diameter hole portion 31 a with one end connected to the guide hole 29. And a large-diameter hole 31b having one end coaxially connected to the other end of the small-diameter hole 31a and having a diameter larger than that of the small-diameter hole 31a, and is formed between the small-diameter hole 31a and the large-diameter hole 31b. An annular step portion 31c facing the opposite side of the guide hole 29 is formed, and a lid member 32 that closes the other end of the large diameter hole portion 31b is screwed to the outer end of the second cylindrical portion 26b.

  The first sliding hole 28 of the casing 26 is slidably fitted with a parking piston 33 that can obtain a parking brake state by a forward operation according to the action of the control fluid pressure for parking on the back side. An annular seal member 40 is attached to the outer periphery of the parking piston 33. A parking control fluid pressure chamber 34 that allows the parking control fluid pressure to act between the rear surface of the parking piston 33 and the partition wall 27 is formed in the first cylindrical portion 26 a of the casing 26.

  The parking piston 33 is connected to one end portion of the parking operation lever 23 in the drum brake 11 via a connecting means 35, and a traction force acting on the connecting means 35 according to the forward operation of the parking piston 33 is the parking operation. As a result, the parking operation lever 23 is rotated to the side on which the drum brake 11 is parked.

  Thus, the connecting means 35 is a rod that passes through the partition wall 27 through the annular seal member 41 in a liquid-tight and slidable manner and is coaxially and integrally connected to the center of the rear end of the parking piston 33. 33a, a stopper 36 connected to the rod 33a and slidably fitted in the guide hole 29, and a connecting rod 37 connecting the stopper 36 and the parking operation lever 23, and is opposite to the partition wall 27. On the side, a stopper ring 42 for preventing the stopper 36 from coming off the guide hole 29 is attached to the end of the guide hole 29.

  Referring also to FIG. 4, one end portion of the parking operation lever 23 is bent in a substantially U shape so as to form a slit 38, and the end portion of the connecting rod 37 inserted through the slit 38. In addition, an enlarged engagement portion 37 a that contacts and engages with one end portion of the parking operation lever 23 is provided. In addition, the contact surface 39 provided on the parking operation lever 23 so as to contact and engage the enlarged engagement portion 37a has an arcuate shape, and acts on the parking operation lever 23 as the parking piston 33 moves forward. The tangent of the contact surface 39 at the contact point of the enlarged engagement portion 37a when the traction force is maximized is not only perpendicular to the traction force acting direction from the connection rod 37 to the parking operation lever 23, but also the connection rod. In the entire stroke area 37, the tangent line at the contact point of the enlarged engagement portion 37a is formed to be perpendicular to the direction of the traction force.

  In addition, the outer surface shape of at least the portion of the enlarged engaging portion 37 a that contacts the contact surface 39 is formed into a curved surface that is convex toward the contact surface 39.

Further, in the casing 26, the parking piston 33 is automatically locked by a temporary action of the parking release control hydraulic pressure corresponding to the forward movement of the parking piston 33 and the subsequent release in order to mechanically lock the parking piston 33 in the forward movement position. There is provided a lock mechanism 43 that performs the lock operation and performs the lock release operation in accordance with the action of the parking release control hydraulic pressure.

  The lock mechanism 43 has an axis perpendicular to the axis of the parking piston 33 and is slidable on the casing 26 while allowing an urging force to act in one axial direction when the parking piston 33 moves forward. It is an intermediate member of the lock piston 44 that is fitted and allows the control pressure for parking release to act in the other axial direction, and the connecting means 35 that connects between the parking piston 33 and the parking operation lever 23. A pair of locking portions 45, 45 provided on the stopper 36, and the locking piston 44 of the locking piston 44 are mechanically locked by engaging the locking portions 45, 45 from the rear to mechanically lock the forward operation position of the parking piston 33. And a pair of lock portions 46 provided at one end in the axial direction.

  Referring also to FIG. 5, the stopper 36 is formed to have a substantially rectangular cross-sectional shape in which the thickness in the direction orthogonal to the axis of the second sliding hole 31 and the guide hole 29 is reduced. The locking portions 45, 45 having a ring shape are fitted and fixed to support bosses 47, 47 protruding from both sides of the stopper 36.

  The lock piston 44 is slidably fitted in the second sliding hole 31 disposed on the rear side of the parking piston 33, and slides in the small diameter hole portion 31a of the second sliding hole 31. A small-diameter portion 44a that can be fitted and an annular step portion 44c that faces the step portion 31c of the second sliding hole 31 are formed between the rear portion of the small-diameter portion 44a and coaxially connected to the small-diameter portion 44a. A large-diameter portion 44b slidably fitted in the large-diameter hole portion 31b of the second sliding hole 31 is integrally provided.

  Between the lock piston 44 and the lid member 32, for example, a pair of springs 48, 48 arranged in parallel are contracted to spring-bias the lock piston 44 toward one axial side, that is, the stopper 36 side. In addition, a parking release control hydraulic pressure is applied between the lock piston 44 and the casing 26 between the stepped portion 44c of the lock piston 44 and the stepped portion 31c of the second sliding hole 31 to bias the lock piston 44 to the other side in the axial direction. An annular parking release control hydraulic pressure chamber 49 is formed, and the pressure receiving area of the lock piston 44 facing the parking release control hydraulic pressure chamber 49 is greater than the pressure receiving area of the parking piston 33 facing the parking control hydraulic pressure chamber 34. Is also set larger.

  Further, on the outer periphery of the small diameter portion 44a and the large diameter portion 44b of the lock piston 44, the parking release control hydraulic pressure chambers 49 are sealed from both sides in the axial direction, and the small diameter hole portion 31a and the large diameter hole portion of the second sliding hole 31 are sealed. Annular seal members 50 and 51 slidably contacting 31b are mounted.

  The small diameter portion 44 a on one end side of the lock piston 44 has a lock portion 46 so as to engage with the locking portions 45, 45 across the stopper 36 at the intermediate portion of the connecting means 35 at the advance position of the parking piston 33. , 46 are integrally provided, and the outer peripheral surfaces of the lock portions 46, 46 are engaged with the stopper 36 in the guide hole 29 having a smaller diameter than the small diameter hole portion 31a of the second sliding hole 31. It is possible to form a tapered shape with the tip side narrowed.

  Moreover, the lock portions 46, 46 are formed with engagement surfaces 46a, 46a that can be engaged with the locking portions 45, 45 from the rear side, and these engagement surfaces 46a,. As it goes to one axial direction, it inclines so that it may become the rearward position of the parking piston 33 in the axial direction.

  In FIG. 6, the parking control hydraulic pressure that acts on the parking control hydraulic chamber 34 and the parking release control hydraulic pressure that acts on the parking release control hydraulic chamber 49 are the hydraulic pressure generated by the hydraulic pressure source 55. The fluid pressure control means 56 is obtained by controlling the parking control fluid pressure chamber 34 to the fluid pressure generation source 55 and the reservoir 57, and for parking. A state in which the first control valve 58 capable of switching the hydraulic pressure lock state of the control hydraulic pressure chamber 34 and the parking release control hydraulic pressure chamber 49 are selectively communicated to the hydraulic pressure generation source 55 and the reservoir 57 and the parking release. And a second control valve 59 capable of switching the hydraulic pressure lock state of the control hydraulic pressure chamber 49.

  When the parking brake state is obtained, the parking control fluid pressure chamber 34 is acted on by the parking control fluid pressure chamber 34 and the parking release control fluid pressure chamber 49 is actuated by the fluid pressure acting on the parking piston control fluid pressure chamber 34. The parking piston 33 is moved forward while suppressing the operation of. Next, when the hydraulic pressure in the parking release control hydraulic pressure chamber 49 is released, the lock piston 44 is actuated in one axial direction by the spring force of the springs 48... And the lock mechanism 43 is moved according to the advance of the parking piston 33 and the lock piston 44. The lock operates.

  That is, as shown in FIGS. 7 to 9, the engaging surfaces 46 a and 46 a formed on the lock portions 46 and 46 at one end of the lock piston 44 are engaged with both the locking portions 45 and 45 of the stopper 36 that is moved forward together with the parking piston 33. Are engaged from behind, and the forward movement state of the parking piston 33 is mechanically locked. However, when the operation of the lock piston 44 in one axial direction is completed, the residual pressure in the parking control hydraulic chamber 34 is released.

  When the parking piston 33 moves forward as described above, the drum brake 11 is parked by the rotation of the parking operation lever 23, and the parking brake state is maintained by locking the forward movement state of the parking piston 33. In addition, since the force for operating the brake shoes 13 for the parking brake in the drum brake 11 is transmitted to the brake shoes 13 and 14 via the parking operation lever 23, the parking drive means 25 is controlled by the lever ratio of the parking operation lever 23. The liquid pressure that should be exerted is relatively small.

When releasing the parking brake state, the hydraulic pressure in the parking control fluid pressure chamber 34 and the parking release control fluid pressure chamber 49 are simultaneously increased. In the pressure increasing process, first, the spring force of the springs 48 is larger than the spring force. When the hydraulic pressure acts on the lock piston 44, the lock piston 44 moves to the other side in the axial direction, thereby releasing the lock state of the lock mechanism 43. Therefore, the parking pressure is released by releasing the hydraulic pressure in the parking control hydraulic pressure chamber 34. The piston 33 moves backward. Thus, when the lock mechanism 43 is unlocked, the parking release control hydraulic pressure chamber 49 is held in a hydraulic pressure lock state, and the lock portions 46 and 46 of the lock piston 44 are moved to a position where contact with the stopper 36 is avoided. It remains moving.

Next, the operation of this embodiment will be described. When the drum brake 11 is operated as a parking brake, the parking control hydraulic pressure is applied to the parking control hydraulic pressure chamber 34 facing the back side of the parking piston 33 of the parking drive means 25. By operating the parking piston 33 forward, it is possible to brake the drum brake 11 to obtain a parking brake state, and the parking operation state by the forward operation of the parking piston 33 is the parking piston 33. Since the parking mechanism 43 is mechanically locked by the temporary action of the parking release control hydraulic pressure according to the forward movement of the vehicle and the subsequent release , the parking brake state can be obtained automatically, and the parking brake state When canceling May be Seshimere act Kingu release control fluid pressure to the locking mechanism 43, it is possible to obtain a parking brake state automatically by a simple structure without power consumption in the parking brake state.

  Further, the lock mechanism 43 has an axis perpendicular to the axis of the parking piston 33 and is slidably fitted to the casing 26 so that an urging force in one axial direction acts when the parking piston 33 moves forward. And a locking piston 44 capable of causing the parking release control pressure to act in the other axial direction, a locking portion 45 provided on a stopper 36 connected to the parking piston 33, and the locking portion , Having a locking portion 46 provided at one end in the axial direction of the lock piston 44, having an engagement surface 46a for mechanically locking the forward operation position of the parking piston 33 from behind. The engaging surface 46a... Becomes the rearward position in the axial direction of the parking piston 33 as it goes to one axial direction of the lock piston 44. I am inclined to.

  Accordingly, it is possible to mechanically lock the forward operation position of the parking piston 33 in response to a change in the forward movement amount from the backward limit of the parking piston 33 in the parking brake state, and the dimensional tolerance, assembly error or brake It is possible to cope with a change in the stroke amount of the parking piston 33 according to the wear of the linings 14 in the shoes 13.

  Further, the stopper 36 provided with the locking portions 45 is disposed in the middle of the connecting means 35 connecting the parking piston 33 and the parking operation lever 23, and the lock portions 46, 46 straddle the stopper 36. Since the forward movement force of the parking piston 33 is transmitted to the parking operation lever 23 of the drum brake 11 via the connecting means 35, the lock mechanism 43 is compact. And simplification.

  Further, an enlarged engaging portion 37a provided at an end of the connecting rod 37 which is a part of the connecting means 35 is brought into contact with and engaged with one end of the parking operation lever 23. An arc-shaped contact surface 39 provided on the parking operation lever 23 for contact and engagement is enlarged when the traction force acting on the parking operation lever 23 is maximized as the parking piston 33 moves forward. The tangent of the contact surface 39 at the contact point of the engaging portion 37a is not only perpendicular to the direction of the traction force acting from the connecting rod 37 to the parking operation lever 23, but also expanded in the entire stroke region of the connecting rod 37. The tangent line at the contact point of the portion 37a is formed so as to be perpendicular to the traction force acting direction.

  Therefore, when the traction force acting on the parking operation lever 23 is maximized, it is possible not only to suppress the twisting between the connecting rod 37 and the parking operation lever 23 and to improve the durability, but also to improve the durability of the connecting rod 37. It is possible to suppress the occurrence of twisting between the connecting rod 37 and the parking operation lever 23 in the entire stroke region, and to further improve the durability.

  Further, since the outer surface shape of at least the portion of the enlarged engaging portion 37a that contacts the contact surface 39 is formed in a curved shape that is convex toward the contact surface 39, the space between the connecting rod 37 and the parking operation lever 23 is increased. The occurrence of twisting can be more effectively suppressed, and the contact area between the parking operation lever 23 and the enlarged engagement portion 37a can be made relatively large to reduce stress.

  Moreover, since the connecting rod 37 can be engaged with and connected to the parking operation lever 23 by inserting the connection rod 37 of the slit 38 provided in the parking operation lever 23, the assembling property is also good.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a front view of a drum brake. FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3. It is a perspective view of a stopper and a lock piston. It is a figure which shows the structure of a hydraulic circuit. It is sectional drawing corresponding to FIG. 2 in a parking brake state. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. FIG. 9 is a sectional view taken along line 9-9 in FIG. 8.

Explanation of symbols

26 ... casing 33 ... parking piston 36 ... stopper 43 ... lock mechanism 44 ... lock piston 45 ... locking part 46 ... lock part 46a ... engagement surface 55 ..Hydraulic pressure generation source 56 ... Hydraulic pressure control means

Claims (1)

The casing (26) fixed to the back plate (12) of the drum brake (11) is connected to the parking operation lever (23) of the drum brake (11) via the connecting means (35) and to the rear side. a parking piston said slidably fitted in the casing (26) as possible to be obtained by the forward operation according to the action of the parking control fluid pressure to the parking brake state of the drum brake (11) (33), In order to mechanically lock the parking piston (33) in the forward position, the parking piston (33) is automatically locked by a temporary action of the parking release control hydraulic pressure corresponding to the forward movement of the parking piston (33) and the subsequent release. together with the so as to unlock it operates in response to the action of the parking release control fluid pressure casing (26) A lock mechanism (43), a hydraulic pressure generation source (55), and a generated hydraulic pressure of the hydraulic pressure generation source (55) to control the parking control hydraulic pressure and the parking release control hydraulic pressure. Hydraulic pressure control means (56) that can be obtained,
The connecting means (35) includes a rod (33a) connected to the rear end of the parking piston (33), a stopper (36) connected to the rod (33a), the stopper (36) and a parking operation lever. (23) It consists of a connecting rod (37) that connects between them,
The locking mechanism (43) has an axis perpendicular to the axis of the parking piston (33) while allowing a biasing force toward one axial direction to act at least when the parking piston (33) moves forward. a lock piston (44) that allows exerting toward the parking release control pressure in the other axial direction together with the slidably fitted the casing (26), provided in front kiss stopper (36) a locking portion (45) which is, before a mechanically locking engagement surface forward operating position of said engaging from behind in the locking portion (45) the parking piston (33) (46a) A lock portion (46) provided at one axial end of the lock piston (44), and the engagement surface (46a) moves toward the one axial direction of the lock piston (44). A parking brake device for a drum brake, wherein the parking brake device is formed so as to be inclined in the axially rearward position of the parking piston (33).

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