JP2008002639A - Parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking brake device which can achieve a uniform surface pressure in a contact surface of a piston plate with a brake disk in a braking state even when the accepting space for the piston plate is restricted. <P>SOLUTION: Brake disks 25 are connected to a rotary shaft arranged in a shaft case 11 in the axial direction of the rotary shaft. Stators 26 to be locked to the shaft case 11 are arranged between brake disks 25. A piston plate 30 is locked to the shaft case 11 so as to be opposed to the endmost brake disk 25. A plate pressing mechanism is provided so as to press the piston plate 30. The piston plate 30 has a contact surface 32 to be brought into pressure contact with the brake disk. The contact surface 32 is a non-flat surface which is recessed in the axial direction in specified radial directions from the outer peripheral edge 32b of the contact surface 32 toward the center, and becomes a flat surface by the elastic deformation of the piston plate 30 caused by the pressure contact with the brake disk 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a parking brake device used for a vehicle or the like, and more particularly to a parking brake device that obtains a braking force of a rotating shaft by a frictional force between a brake disk and a stator.

As a conventional parking brake device, for example, a parking brake device disclosed in Patent Document 1 is known.
The parking brake device disclosed in Patent Document 1 is a multi-plate brake disc that is spline-fitted to a differential gear shaft, a brake piston that is housed in an axle case and pushes the brake disc, and an operating arm. And a slide pin for pushing the brake piston.
The brake piston is formed of a metal material, but the flange portion of the brake piston pressed by the slide pin has a flat plate shape.
In this type of parking brake device, when the operating arm is operated, the slide pin pushes the brake piston, and the pushed brake piston pushes the brake disc.
The braking force for the differential gear shaft is obtained by the frictional force of the brake disc.

As another related art, for example, there is a disc brake device disclosed in Patent Document 2.
In this disc brake device, an uneven portion that generates dynamic pressure between the rotating rotor and the stationary stator is formed on at least one of the rotor and the stator, and at least one of the rotor and the stator is circumferential. It is waved in the direction.
Furthermore, a presser plate is provided inside both ends of the piston, and the presser plate clamps the rotor and the stator, which are alternately arranged, from both sides at the time of braking, so that the rotor and the stator are in close contact with each other.
Japanese Patent Laid-Open No. 61-229651 JP-A-6-123319

In the conventional technique, in the braking state, the slide pin corresponding to the plate pressing mechanism locally pushes the brake piston as the piston plate, so that local deflection of the piston plate cannot be avoided.
When the piston plate is bent, the contact surface between the piston plate and the brake disk cannot obtain a uniform surface pressure, and the braking force is reduced as compared with the case where a uniform surface pressure is obtained at the contact surface of both. There is a case.
In this case, it is conceivable to increase the rigidity of the piston plate by suppressing the bending by increasing the plate thickness of the piston plate. However, in addition to requiring a space in the axial direction of the rotating shaft corresponding to the increase in the plate thickness, the parking brake The weight of the device increases.
In particular, when the accommodation space of the piston plate is restricted, the plate thickness of the piston plate cannot be set large.

Further, in the technique disclosed in Patent Document 2, the presser plate corresponding to the piston plate has a flat plate shape.
In order to press at least one of a rotor (corresponding to a brake disc) and a stator having a piston plate wavy in the circumferential direction, and to make the rotor and the stator come into close contact with each other, the piston from the piston corresponding to the plate pressing mechanism A large pressing force is required.
In order to increase the pressing force from the piston, there is a possibility that an increase in size and complexity of the plate pressing mechanism cannot be avoided.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide a contact surface between the piston plate and the brake disk during braking even when the accommodation space of the piston plate is restricted. The present invention provides a parking brake device that can obtain a uniform surface pressure.

  In order to achieve the above object, according to the present invention, a brake disk is connected to a rotating shaft in a shaft case in the axial direction of the rotating shaft, and a stator locked to the shaft case is interposed between the brake disks. A perforated disk-like piston plate is provided on the shaft case facing the brake disc at the outermost end, and is provided with a plate pressing mechanism that presses the piston plate toward the brake disc; The disc, the stator, and the piston plate are movable in the axial direction of the rotating shaft, and the plate pressing mechanism presses the piston plate, thereby causing the rotation by the contact between the brake disc and the stator. In the parking brake device for obtaining a braking force on the shaft, the piston plate is pressed by the plate pressing mechanism. A contact surface that is in pressure contact with the brake disk, and the contact surface is a non-flat surface that is recessed in the axial direction on the plate pressing mechanism side in a specific radial direction of the contact surface, and A flat surface is formed by elastic deformation of the piston plate based on pressure contact with the brake disk.

According to the present invention, when the parking brake device is released from the braking state, the piston plate is not pressed by the plate pressing mechanism, so that the contact surface of the piston plate maintains a non-flat surface.
On the other hand, in the braking state, the piston plate is pressed by the plate pressing mechanism, and the piston plate and the brake disk are pressed against each other.
Due to the pressure contact between the piston plate and the brake disc, the piston plate is elastically deformed, and the contact surface of the piston plate becomes a flat surface.
By increasing the pressing force from the plate pressing mechanism, a uniform surface pressure can be obtained on the contact surface between the piston plate and the brake disk.

According to the present invention, in the parking brake device described above, the piston plate may have a constant thickness, and the contact surface may be formed by at least one of an axial curve and a bend of the piston plate.
In this case, the non-flat contact surface can be formed only by processing a piston plate having a constant plate thickness by at least one of bending and bending.

Further, in the present invention, in the parking brake device described above, instead of the bending and bending of the piston plate in the axial direction, the piston plate has a thickness corresponding to the contact surface, and from the outer peripheral edge of the contact surface. The plate thickness may be reduced toward the center.
In this case, there is no need to bend or bend the piston plate.

Furthermore, in the parking brake device, the piston plate has a pressed surface that presses the plate pressing mechanism, and the pressed surface has a top corresponding to the most depressed portion of the contact surface. The top portion may be pressed by a plate pressing mechanism.
In this case, in the braking state, the plate pressing mechanism concentrates and presses the top of the pressed surface, so that the piston plate and the brake disk are pressed against each other.
The plate pressing mechanism does not need to press the entire pressed surface of the piston plate.

  According to the present invention, there is provided a parking brake device capable of obtaining a uniform surface pressure on a contact surface between a piston plate and a brake disk during braking even when the accommodation space of the piston plate is restricted. be able to.

Hereinafter, a parking brake device according to an embodiment of the present invention will be described with reference to the drawings.
The parking brake device according to this embodiment is an example applied to a wet parking brake provided in a forklift as an industrial vehicle.
FIG. 1 is a longitudinal sectional view showing a parking brake device according to an embodiment of the present invention, in which a part of driving force transmitting means in a forklift is shown.

The driving force transmission means includes a shaft case 11 configured by a combination of first to third case members 12, 13, and 14.
A space portion 15 formed in the shaft case 11 is filled with lubricating oil, and a rotatable output shaft 16 is accommodated through the shaft case 11.
The output shaft 16 is a shaft body that transmits a rotational force from a drive source to a wheel (not shown), and includes a small diameter shaft portion 16a and a large diameter shaft portion 16b.
One of the output shafts 16 (right side in FIG. 1) is connected to a differential mechanism (difference) (not shown), and the other (left side in FIG. 1) is connected to a transmission mechanism (not shown).

The differential mechanism includes a differential case 18, and the differential case 18 includes a cylindrical shaft support portion 19 through which a part of the output shaft 16 passes.
The output shaft 16 and the differential case 18 can be rotated synchronously and differentially.
In this embodiment, the output shaft 16 and the shaft support portion 19 function as a rotation shaft.
A bearing 20 is interposed between the differential mechanism side of the shaft support 19 and the first case member 12.
That is, it can be said that the rotating shaft is rotatably supported by the shaft case 11 via the bearing 20.

The portion of the output shaft 16 facing the third case member 14 forms a large-diameter shaft portion 16b having an enlarged diameter, and an annular seal member 21 is provided between the large-diameter shaft portion 16b and the third case member 14. Is intervening.
The seal member 21 prevents leakage of lubricating oil from the space 15 to the transmission mechanism side.

By the way, a through hole 13 a is formed in the second case member 13, and the inner peripheral surface of the through hole 13 a faces a part of the outer peripheral surface of the shaft support portion 19.
A large number of perforated disc-shaped brake disks 25 are arranged on the outer peripheral surface of the shaft support portion 19 facing the second case member 13 by spline fitting.
The brake disc 25 provided in the axial direction of the rotating shaft in the shaft support portion 19 has a friction surface perpendicular to the axial direction of the output shaft 16.
The spline-fitted brake disc 25 is movable in the axial direction of the rotating shaft and is locked with respect to the rotating direction of the rotating shaft.
Accordingly, the brake disk 25 rotates in synchronization with the shaft support portion 19 as the shaft support portion 19 rotates.

A large number of perforated disk-shaped stators 26 are arranged on the inner peripheral surface of the through hole 13 a of the second case member 13.
These stators 26 are connected in the axial direction of the rotation shaft in the second case member 13 and have a friction surface perpendicular to the axial direction of the output shaft 16.
The outer peripheral edge of the stator 26 has a locking claw (not shown) that is locked to the second case member 13 in the rotation direction of the rotation shaft.
A locking groove (not shown) corresponding to the locking claw of the stator 26 is formed on the inner peripheral surface of the second case member 13 along the axial direction of the rotating shaft.
For this reason, the stator 26 is movable in the axial direction of the rotating shaft.
The stators 26 and the brake disks 25 are alternately arranged in the axial direction of the rotating shaft.
In this embodiment, the friction surface of the stator 26 faces the friction surface of the brake disk 25.
The brake disc 25 closest to the differential mechanism side faces the end surface of the first case member 12.

The second case member 13 is engaged with a perforated disk-like piston plate 30 that faces the endmost brake disk 25 closest to the speed change mechanism side.
The piston plate 30 is a plate that receives pressure from a plate pressing mechanism 35 described below and is in pressure contact with the brake disc 25 at the end.
The piston plate 30 is formed from an elastic metal material.
As shown in FIGS. 2 and 3, a through hole 31 that allows the shaft support 19 to be inserted is formed in the center of the piston plate 30.
On the outer periphery of the piston plate 30, a locking claw 30 a that protrudes toward the outer diameter side is provided.
The locking claw 30 a corresponds to a locking groove (not shown) of the second case member 13.

The piston plate 30 has a contact surface 32 that is in pressure contact with the outermost brake disc 25 and a pressed surface 33 that is opposite to the contact surface and is pressed by the plate pressing mechanism 35.
As shown in FIG. 3, the piston plate 30 includes a pair of upper and lower outer peripheral edges 32 a that are displaced from the center of the piston plate 30 in the axial direction on the differential mechanism side based on the curvature in the axial direction.
That is, the contact surface 32 is a non-flat surface that is recessed toward the plate pressing mechanism 35 in the upper and lower radial directions from the outer peripheral edge 32a of the contact surface 32 toward the center.
The position of the most concave portion 32b formed on the contact surface 32 coincides with the vertical position of the axis A of the output shaft.
In this embodiment, the contact surface 32 which is a non-flat surface is formed by the curve of the piston plate 30 in the axial direction.
Therefore, in a state where the braking state is released, the gap between the piston plate 30 and the brake disk 25 becomes wider toward the most concave portion 32b in the upper and lower radial directions, and becomes narrower toward the pair of upper and lower outer peripheral edges 32a. .
On the other hand, the pressed surface 33 is formed with a top 33 a that protrudes toward the plate pressing mechanism 35 due to the curvature of the piston plate 30.
The top portion 33a corresponds to the most recessed portion 32b which is the most depressed portion on the contact surface 32, and exists on both sides of the through hole 31 as shown in FIG.
The top portion 33 a is a portion that receives the pressure of the plate pressing mechanism 35.
Therefore, although only one side is shown in the side view in FIG. 3, the most recessed part 32b exists as a left-right pair.
In addition, in the explanatory view of the piston plate 30 in FIG. 3, a front view, a side view, and a plan view of the piston plate 30 are shown, but the curvature of the piston plate 30 shown in FIG. It is exaggerated rather than curved.
The actual degree of bending in the piston plate 30 is a degree of bending that is not visually grasped.
Further, as shown in FIGS. 1 and 2, the piston plate 30 is provided with a spring receiving portion 34 that protrudes outward at the outer peripheral edge of the piston plate 30.
The spring receiving portion 34 receives one end of a return spring 39 interposed between the first shaft case 12 and the piston plate 30.
The return spring 39 is a return means having a biasing force that returns the piston plate 30 to the original position when the brake state is released from the brake state.
In this embodiment, the return means using the return spring 39 is used. However, for example, when the clearance between the brake disk 25 and the stator 26 is narrow and the resistance during sliding is small, the lubricating oil accompanying the rotation of the disk 25 is used. The piston plate 30 may be returned to the original position together with the brake disk 25 and the stator 26 using the pressure generated by the shearing of the brake.
In this case, the return spring 39 and the spring receiving part 34 as a return means are unnecessary.

Next, the plate pressing mechanism 35 will be described.
The plate pressing mechanism 35 is a mechanism for pressing the piston plate 30 toward the brake disc 25 during braking.
As shown in FIG. 2, the plate pressing mechanism 35 includes a fulcrum shaft 36 that crosses the lower side of the rotation shaft, a fork 37 as a pressing member attached to the fulcrum shaft 36, and a tilt fixed to the end of the fulcrum shaft 36. The lever 38 is connected to a wire (not shown) and has an operation lever (not shown) that interlocks the tilt lever 38 by operation.
The operation lever is a toggle lever, and is an ON / OFF type lever that applies a constant pressing force to the fork 37 when the operation lever is in a braking state.

The fulcrum shaft 36 is a shaft body that is rotatably supported with respect to the shaft case 11, and traverses the lower part of the rotation shaft in the vicinity of the piston plate 30.
The fork 37 is a member that swings around the fulcrum shaft 36 and presses the piston plate 30 by swinging.
As shown in FIG. 2, the fork 37 has a bifurcated shape so as not to interfere with the rotating shaft when swinging.
As shown in FIG. 1, the pressing portion 37 a of the fork 37 that presses the piston plate 30 has substantially the same height as the shaft core A on both sides of the output shaft 16.
That is, the pressing portion 37 a faces the pair of left and right top portions 33 a on the pressed surface 33 of the piston plate 30.
The fork 37 presses the top 33a of the piston plate 30 during braking.

  As described above, the parking brake device of this embodiment mainly includes the brake disk 25, the stator 26, the piston plate 30, and the plate pressing mechanism 35. The plate pressing mechanism 35 presses the piston plate 30, and the piston plate. The braking disk 25 and the stator 26 are brought into contact with each other based on the pressure of 30 to obtain a braking force against the rotation shaft.

Next, the operation of the parking brake device according to this embodiment will be described.
First, in a state where the braking state of the parking brake device is released, the fork 37 of the plate pressing mechanism 35 does not interfere with the piston plate 30 and does not press the piston plate 30.
As shown in FIG. 4A, when the braking state of the parking brake device is released, the gap between the contact surface 32 of the piston plate 30 and the brake disk 25, the brake disk 25, and the stator 26 The gap is maintained, and at this time, the rotation shaft is in a rotatable state.
Note that the curvature of the piston plate 30 shown in FIG. 4A is exaggerated from the actual curvature for convenience of explanation.

Next, the case where a parking brake apparatus is made into a braking state is demonstrated.
When the operation lever is operated to be on the braking side, the tilting lever 38 is interlocked and rotates about the fulcrum shaft 36 as a fulcrum.
As the fulcrum shaft 36 rotates, the fork 37 comes into contact with the top 33 a of the piston plate 30, and the fork 37 presses the piston plate 30 as the fulcrum shaft 36 further rotates.
At this time, the fork 37 concentrates and presses the top 33 a of the pressed surface 33 of the piston plate 30.
The piston plate 30 is moved in the axial direction on the brake disc 25 side under the pressure of the fork 37.

Due to the movement of the piston plate 30 in the axial direction based on the pressing of the fork 37, the pair of upper and lower outer peripheral edges 32 a of the piston plate 30 are brought into contact with the brake disk 25.
As the fork 37 continues to be pressed, the gaps between the brake disks 25 and the stators 26 are narrowed, and the two 25 and 26 come into contact with each other.
When the pressing force by the fork 37 further increases, the piston plate 30 is pressed against the brake disc 25 and elastically deformed.
At this time, the contact surface 32a that contacts the brake disc 25 increases the surface contact range with the brake disc 25 from the vicinity of the pair of upper and lower outer peripheral edges 32a toward the shaft core. The contact surface 32 becomes a flat surface and is pressed against the brake disc 25.
As shown in FIG. 4B, when the pressing force is further increased with respect to the piston plate 30 deformed into a flat shape, a uniform surface pressure is obtained at the contact surface 32 between the piston plate 30 and the brake disc 25. It is done.

By obtaining a uniform surface pressure at the contact surface 32 between the piston plate 30 and the brake disk 25, a uniform surface pressure acts on the friction surfaces of the brake disks 25 and the stators 26.
Sufficient braking force on the rotating shaft can be obtained by applying a uniform surface pressure to the friction surfaces of the brake disks 25 and the stators 26.
In this embodiment, since the operation lever is a toggle-type lever, when the operation lever is operated to be on the braking side, a pressing force of a predetermined level or more is set to act on the piston plate 30 through the fork 37. .

When releasing the braking state of the parking brake device, the pressing of the fork 37 against the piston plate 30 is released by operating the operation lever to the release side.
For this reason, the piston plate 30 that has been deformed into a flat shape under the pressure of the fork 37 returns to its original curved shape due to elasticity.
Further, the piston plate 30 is returned to the original position by receiving the urging force of the return spring 39, and the brake disc 25 and the stator 26 are moved in the axial direction on the fork 37 side by receiving the pressure of the lubricating oil, and return to the original position. Return.

The parking brake device according to the embodiment of the present invention has the following effects.
(1) Since the piston plate 30 is not pressed by the plate pressing mechanism 35 when the brake is released, the contact surface 32 of the piston plate 30 maintains a non-flat surface. On the other hand, the piston plate 30 at the time of braking is pressed by the fork 37, and the piston plate 30 and the brake disc 25 are pressed against each other, so that the piston plate 30 is elastically deformed and the contact surface 32 becomes a flat surface. By continuing to increase the pressing force from the fork 37, a uniform surface pressure can be obtained at the contact surface 32 between the piston plate 30 and the brake disk 25.
(2) Since the fork 37 of the plate pressing mechanism 35 presses the top portion 33a of the pressed surface 33 of the piston plate 30 in the axial direction of the brake disk 25, the fork 37 presses the top portion 33a and increases the pressing force of the fork 37. Only by doing so, the pressure contact between the piston plate 30 and the brake disk 25 is possible. Therefore, it is possible to use the plate pressing mechanism 35 that exerts a large pressing force locally.
(3) Since the curved piston plate 30 is used, the axial space of the parking brake device can be suppressed and the axial space is restricted as compared with the case where the plate thickness of the piston plate 30 is increased. Even when receiving, a uniform surface pressure can be obtained at the contact surface 32 between the piston plate 30 and the brake disc 25 during braking. Further, an increase in the weight of the parking brake device can be prevented.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.

  In the above embodiment, the piston plate 30 is curved, but for example, a piston plate 40 shown in FIG. 5A may be used. The piston plate 40 according to this other example has a constant plate thickness, and a contact surface 42 and a pressed surface 43 which are non-flat surfaces are formed by bending instead of bending. The piston plate 40 has a pair of upper and lower outer peripheral edges 42a, a most concave part 42b, and a top part 43a. In this case, there are almost the same effects as the above-described embodiment.

Furthermore, a piston plate 50 shown in FIG. 5B may be used, and this piston plate 50 has a constant plate thickness and is formed with a plurality of curves in the radial direction. In addition to a pair of upper and lower outer peripheral edges 52 a, a plurality of concave portions 52 b are formed on the contact surface 52, and a plurality of top portions 53 a are formed on the pressed surface 53.
In this case, it is preferable to use a plate pressing mechanism having a pressing member that presses each top 53a. When the pressing member presses the plurality of top portions 53a at the time of braking, the surface pressure at the contact surface 52 between the piston plate 50 and the brake disk 25 can be made more uniform.
Note that the bending or bending of the piston plates 40 and 50 shown in FIGS. 5A and 5B is shown exaggerated over the actual bending or bending for convenience of explanation.
The actual curve or bend is a curve that can hardly be grasped visually.

In the piston plate having a certain plate thickness, the abutting surface may be a non-flat surface based on at least one of bending and bending, and a top portion is formed on the pressed surface based on at least one of bending and bending. .
In addition, the contact surface 32 of the above embodiment is a non-flat surface that is recessed in the axial direction with respect to the upper and lower radial directions as a specific radial direction, but the specific radial direction is not specified in the vertical and horizontal directions, It suffices to exist on an extension line that crosses the axis A.

Moreover, in addition to the piston plates 40 and 50 according to the above-described another example, a piston plate 60 shown in FIG. 6 may be used.
As shown in FIG. 6 (a), the piston plate 60 has a plate thickness corresponding to the abutment surface 62, and a pair of upper and lower outer peripheral edges 62a positioned at a position shifted from the center of the piston plate in the axial direction of the rotating shaft. And has a recess 62b.
The pressed surface 63 of the piston plate 60 is a surface perpendicular to the axial direction.
That is, the plate thickness of the piston plate 60 decreases in the axial direction from the pair of upper and lower outer peripheral edges 62a toward the most recessed portion 62b.
The piston plate 60 that comes into contact with the brake disc 25 by the pressing of the plate pressing mechanism 35 is elastically deformed as shown in FIG. 6B, and the contact surface 62 of the brake disc 25 becomes flat.
Note that the gradual decrease in the plate thickness of the piston plate 60 shown in FIGS. 6A and 6B is exaggerated from the actual gradual decrease for convenience of explanation.
The actual gradual decrease in thickness is a gradual decrease that can hardly be grasped visually.
In this example, the pressed surface 63 is a flat surface. However, this is not intended to prevent the top surface from being provided on the pressed surface, and a top portion corresponding to the re-recessed portion 62b may be provided even when the plate thickness is not constant.

  In the above-described embodiment, the pressing member of the plate pressing mechanism 35 includes the swinging fork 37 using the fulcrum shaft. It may be a member, and the type and structure are not particularly limited as long as it is a pressing member that presses at least the top of the piston plate in the axial direction of the rotation shaft.

It is a longitudinal section showing a parking brake device concerning an embodiment of the present invention. It is a front view which shows the principal part of the parking brake apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the front of the piston plate with which the parking brake apparatus which concerns on embodiment of this invention is equipped, a plane, and a side surface. It is a principal part side view explaining operation | movement of the parking brake apparatus which concerns on embodiment of this invention, Fig.4 (a) shows the state by which the braking state was cancelled | released, FIG.4 (b) shows a braking state. FIG. 5A is a side view of a piston plate by bending, and FIG. 5B is a side view showing a piston plate having a plurality of tops on a pressed surface. is there. Furthermore, it is a side view of the piston plate which concerns on another example, Fig.6 (a) shows the state by which the braking state was cancelled | released, and FIG.4 (b) shows the braking state.

Explanation of symbols

11 Shaft Case 12 1st Shaft Case Member 13 2nd Shaft Case Member 14 3rd Shaft Case Member 16 Output Shaft 19 Shaft Support 25 Brake Disc 26 Stator 30, 40, 50, 60 Piston Plates 32, 42, 54, 64 Contact Surface 32a, 42a, 62a Outer peripheral edge 32b, 42b, 62b Recessed portion 33 Pressed surface 33a, 43a, 53a, 54a Top 35 Plate pressing mechanism 36 Support point shaft 37 Fork 37a Pressing portion 38 Tilt lever A Output shaft axis

Claims (4)

A brake disk is connected to the rotating shaft in the shaft case in the axial direction of the rotating shaft, a stator that is locked to the shaft case is interposed between the brake disks, and a perforated disk-shaped piston plate Is opposed to the brake disc at the extreme end and is locked to the shaft case, and is provided with a plate pressing mechanism that presses the piston plate toward the brake disc. The brake disc, the stator, and the piston plate are In the parking brake device that is movable in the axial direction of the rotating shaft, and the plate pressing mechanism presses the piston plate to obtain a braking force against the rotating shaft by contact between the brake disk and the stator,
The piston plate has an abutting surface that comes into pressure contact with the brake disc by pressing of the plate pressing mechanism,
The contact surface is a non-flat surface that is recessed in the axial direction on the plate pressing mechanism side in a specific radial direction of the contact surface, and due to elastic deformation of the piston plate based on pressure contact with the brake disk. A parking brake device characterized by a flat surface. The parking brake device according to claim 1, wherein the piston plate has a constant plate thickness, and the contact surface is formed by at least one of an axial curve and a bend of the piston plate. The parking brake device according to claim 1, wherein the piston plate has a plate thickness corresponding to the contact surface, and the plate thickness decreases from the outer peripheral edge of the contact surface toward the center. The piston plate has a pressed surface that presses the plate pressing mechanism, and the pressed surface has a top corresponding to the most depressed portion of the contact surface, and the top presses the plate pressing mechanism. The parking brake device according to any one of claims 1 to 3, wherein the parking brake device is provided.

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