JP4775137B2 - Parking brake equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking brake device which can prevent a drop of a braking force even when the accepting space for a piston plate is restricted or the remarkable difference of a surface pressure exist on the piston plate in a braking state. <P>SOLUTION: The piston plate 29 is composed of a first plate body 30 and a second plate body 35. The first plate body 30 has a surface 32 to be pressed by means of a plate pressing mechanism 38 and a first contact surface 33 to be brought into contact with the second plate body 35. The first contact surface 33 has a pair of edge contact portions 33a formed on an outer peripheral side in specified radial directions and intermediate contact portions 33b. The edge contact portions 33a are flat planes perpendicular to the axial direction. Stepped portions 34 are formed at the boundaries between the edge contact portions 33a and the intermediate contact portions 33b so as to set the edge contact portions 33a at the positions nearer to the brake disk 25 than the intermediate contact portions 33b. <P>COPYRIGHT: (C)2008,JPO&amp;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 on the contact surface of the brake disk.

As another related art, for example, there is a wet disk brake device for a vehicle disclosed in Patent Document 2.
This wet disk brake device for a vehicle is slidable in the axial direction on a rotating disk attached to an axle shaft so as to be slidable in the axial direction, a fixed disk disposed opposite to the rotating disk, and a housing. And a pressure disk disposed opposite to the pressure disk.
The pressing disk is a disk that is moved in the circumferential direction by a parking brake operation.
Further, a cam is provided between the pressing disk and the housing wall surface to generate a thrust force that presses the pressing disk against the pressure receiving disk when the pressing disk moves in the circumferential direction.
Japanese Patent Laid-Open No. 61-229651 Japanese Utility Model Publication No. 58-67135

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 pressure difference between the piston plate and the brake disk becomes significant, and if there is a significant difference in contact pressure between the contact surfaces of the two, the parking brake device As a result, the braking force may decrease.
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, a pressure disk corresponding to a piston plate is pressed against a pressure receiving disk by a parking brake operation, and the pressure receiving disk corresponds to a rotating disk corresponding to a brake disk and a stator. The point which presses the fixed disk to perform is only disclosed, and the problem of patent document 1 cannot be solved.

  The present invention has been made in view of the above problems, and the object of the present invention is to control the piston plate even when the accommodation space of the piston plate is restricted or there is a significant difference in surface pressure during braking. The object is to provide a parking brake device that can prevent a reduction in power.

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 a first plug connected in the axial direction. A first plate body having a pressed surface to be pressed by the plate pressing mechanism and a first contact surface to be in contact with the second plate body, The two-plate body has a disk contact surface that is in pressure contact with the brake disk, and a second contact surface that faces the first plate body, and the first contact surface or the second contact surface is a corresponding contact. A pair of end contact portions formed near the outer periphery in a specific radial direction of the surface, and an intermediate contact portion formed between the pair of end contact portions, the end contact portion Is a flat surface perpendicular to the axial direction, and a step portion that sets the end contact portion closer to the brake disc than the intermediate contact portion is formed between the end contact portion and the intermediate contact portion. is formed at the boundary between parts, said plate pressing mechanism and the pressed portion in contact are present in the pressed surface The pressed portion is characterized Rukoto is set at a position corresponding to the center abutting part.

According to the present invention, when the parking brake device is released from the braking state, the first plate body is not pressed against the first plate body and the second plate body because the first plate body is not pressed by the plate pressing mechanism.
On the other hand, in the braking state, the first plate body is pressed by the plate pressing mechanism, the first plate body presses the second plate body, and the second plate body presses the brake disc.
Since the step portion is formed at the boundary between the end contact portion and the intermediate contact portion formed on the first contact surface or the second contact surface, the pressing force at which the plate pressing mechanism is locally concentrated Is applied to the pressed surface of the first plate body, the pressing force against the second plate body is mainly dispersed in the vicinity of the stepped portion.
That is, during braking, even if there is a significant difference in surface pressure between the first contact surface and the second contact surface, the surface pressure is dispersed so that the braking force against the rotation shaft does not decrease.

In the present invention, in the parking brake device described above, the stepped portion may be a pair of upper and lower parallel steps on the first contact surface .

  ADVANTAGE OF THE INVENTION According to this invention, even if the accommodation space of a piston plate receives restrictions and the range of remarkable surface pressure exists in a piston plate at the time of braking, the parking brake apparatus which can prevent the fall of braking force is provided. 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.

A 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-shaped piston plate 29 that faces the endmost brake disk 25 closest to the speed change mechanism side.
The piston plate 29 according to this embodiment includes a first plate body 30 that faces a plate pressing mechanism 38 described below in the axial direction and a second plate body 35 that faces a brake disk in the axial direction.
The first plate body 30 is a plate that receives pressure from the plate pressing mechanism 38 and is pressed against the second plate body 35.
The second plate body 35 is a plate that is in pressure contact with the first plate body 30 that is pressed by the plate pressing mechanism 38 and that is in pressure contact with the outermost brake disc 25.
The first plate body 30 and the second plate body 35 are formed of a metal material having elasticity.

As shown in FIGS. 2 and 3, a through hole 31 that allows insertion of the shaft support portion 19 is formed at the center of the first plate body 30.
On the outer periphery of the first plate body 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) in the second case member 13.
Further, as shown in FIGS. 1 and 2, the first plate body 30 is provided with a spring receiving portion 30 b that protrudes outward at the outer peripheral edge of the first plate body 30.
Spring receiving portion 30b is made as that the first to case member 12 a return spring 42 interposed between the first plate member 30 receiving one end.
The return spring 42 is a return means having a biasing force that returns the first plate body 30 to the original position when the braking state is released from the braking state.
In this embodiment, the return means using the return spring 42 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, lubrication accompanying the rotation of the brake disk 25 is performed. The first plate body 30 and the second plate body 35 may be returned to their original positions together with the brake disk 25 and the stator 26 by using pressure generated by oil shear.
In this case, the return spring 42 and the spring receiving portion 30b as return means are not necessary.

The first plate body 30 includes a pressed surface 32 that is pressed by the plate pressing mechanism 38 and a first contact surface 33 that contacts the second plate body 35.
The pressed surface 32 is formed as a flat surface perpendicular to the axial direction of the output shaft 16.
On both the left and right sides of the through-hole 31 in the pressed surface 32, there are pressed portions 32a that come into contact with the plate pressing mechanism 38.

The first contact surface 33, which is the opposite surface of the pressed surface 32, is formed near the upper and lower outer circumferences of the first contact surface 33 in the vertical direction that is a specific radial direction of the first contact surface 33. It has a pair of upper and lower end contact portions 33a and a pair of left and right intermediate contact portions 33b formed between the pair of upper and lower end contact portions 33a.
The pair of end contact portions 33 a and the intermediate contact portion 33 b are both formed as flat surfaces perpendicular to the axial direction of the output shaft 16.
A step portion 34 having a step is formed at the boundary between the end contact portion 33a and the intermediate contact portion 33b so that the end contact portion 33a is closer to the friction surface of the brake disc 25 than the intermediate contact portion 33b. Has been.
For this reason, the plate | board thickness of the site | part corresponding to the edge part contact part 33a is set larger than the plate | board thickness of the site | part corresponding to the intermediate contact part 33b.

The step portion 34 of this embodiment is a pair of upper and lower parallel steps on the first contact surface 33.
The provision of the stepped portion 34 on the first contact surface 33 that is in pressure contact with the second plate body 35 means that when the pressing force from the plate pressing mechanism 38 is concentrated on the pressed portion 32a, There is an intention to disperse the pressing force against the second plate body 35 in the vicinity of the stepped portion 34 in the state of pressure contact.
Incidentally, the pressed portion 32a that contacts the plate pressing mechanism 38 is set at a position corresponding to the pair of left and right intermediate contact portions 33b.
In addition, in explanatory drawing of the 1st plate body 30 of FIG. 3, the front view of the 1st plate body 30, the side view, and the top view are shown.
FIG. 4 is a perspective view of the first plate body 30 viewed from the first contact surface 33 side.
The step of the step portion 34 of the first plate body 30 shown in FIGS. 3 and 4 is shown exaggerated from the actual step for convenience of explanation.
The actual level difference in the first plate body 30 is a level that can be visually grasped.

Next, the second plate body 35 will be described.
The second plate body 35 has a perforated disk shape, and a locking claw (not shown) that protrudes toward the outer diameter side is provided on the outer periphery of the second plate body 35.
This locking claw corresponds to a locking groove (not shown) of the second case member 13.
The second plate body 35 has a second contact surface 36 that faces the first plate body 30, and a disk contact surface 37 that presses against the outermost brake disk 25.
Both the second contact surface 36 and the disk contact surface 37 are formed as flat surfaces perpendicular to the axial direction of the output shaft 16.

Next, the plate pressing mechanism 38 will be described.
The plate pressing mechanism 38 is a mechanism for pressing the first plate body 30 toward the brake disc 25 during braking.
As shown in FIG. 2, the plate pressing mechanism 38 includes a fulcrum shaft 39 that crosses below the rotation shaft, a fork 40 as a pressing member attached to the fulcrum shaft 39, and a tilt that is fixed to the end of the fulcrum shaft 39. It has a lever 41 and an operation lever (not shown) connected to a wire (not shown) and interlocking the tilting lever 41 by an operation.
The operation lever is a toggle lever, and is an ON / OFF type lever that applies a constant pressing force to the fork 40 when the operation lever is in a braking state.

The fulcrum shaft 39 is a shaft body that is rotatably supported with respect to the shaft case 11, and crosses below the rotation shaft in the vicinity of the first plate body 30.
The fork 40 is a member that swings around a fulcrum shaft 39 and presses the first plate body 30 by swinging.
As shown in FIG. 2, the fork 40 has a bifurcated shape so as not to interfere with the rotating shaft when swinging.
As shown in FIG. 1, the pressing portion 40 a of the fork 40 that presses the first plate body 30 has substantially the same height as the axis A on both sides of the output shaft 16.
That is, the pressing portion 40 a faces the pair of left and right pressed portions 32 a on the pressed surface 32 of the first plate body 30.
The fork 40 presses the pressed portion 32a of the first plate body 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 29 including the first plate body 30 and the second plate body 35, and the plate pressing mechanism 38. The plate pressing mechanism 38 presses the first plate body 30 and obtains a braking force with respect to the rotating shaft by contact between the brake disk 25 and the stator 26 based on the pressing of the first plate body 30 and the second plate body 35. ing.

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 40 of the plate pressing mechanism 38 does not interfere with the first plate body 30 and does not press the first plate body 30.
As shown in FIG. 5A, when the braking state of the parking brake device is released, the gap between the pressed surface 32 of the first plate body 30 and the second contact surface 36 of the second plate body 35 The gap between the disc contact surface 37 of the second plate 35 and the brake disc 25 and the gap between each brake disc 25 and each stator 26 are maintained, and at this time, the rotating shaft is in a rotatable state.
Note that the step of the step portion 34 of the first plate body 30 shown in FIG. 5A is exaggerated from the actual step 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 41 is interlocked and rotates about the fulcrum shaft 39 as a fulcrum.
As the fulcrum shaft 39 rotates, the fork 40 comes into contact with the pressed portion 32 a of the first plate body 30, and the fork 40 presses the first plate body 30 as the fulcrum shaft 39 further rotates.
At this time, the fork 40 concentrates and presses the pressed portion 32 a on the pressed surface 32 of the first plate body 30.
The first plate body 30 is moved in the axial direction on the brake disc 25 side under the pressure of the fork 40.

By the movement of the first plate body 30 in the axial direction based on the pressing of the fork 40, the end contact portion 33a of the first plate body 30 is brought into contact with the second plate body 35, and further, the second plate body 35 is It abuts against the brake disc 25.
As the fork 40 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 40 further increases, the first plate body 30 is finally pressed against the second plate body 35 and elastically deformed as shown in FIG. 5B.

At this time, the vicinity of the center of the intermediate contact portion 33 b that contacts the brake disk 25 is curved in the axial direction by elastic deformation and contacts the second contact surface 36 of the second plate body 35.
In this state, the pressing force received in a concentrated manner from the fork 40 in the pressed portion 32a is dispersed in a region centered on the step portion 34, and the surface pressure on the second plate body 35 in the vicinity of the step portion 34 is different from that of other portions. It is in a high state in comparison.
In this embodiment, as shown in FIG. 6A, a region S having a high surface pressure centered on the step portion 34 (a range indicated by hatching in FIG. 6A) is generated for each step portion 34. Most of the pressing force acts on the second plate body through the four regions S.
In other words, the four step portions 34 provided on the first plate body 30 distribute the local pressing force received by the pressed portion 32 a to the region S, and a significant surface pressure on the contact surface with the second plate body 35. Even if there is a difference of (2), a well-balanced pressing force is applied to the second plate body 35.

The point that the surface pressure with a difference in the first plate body 30 is dispersed in a balanced manner will be further described with reference to a comparative example shown in FIG.
The comparative example shown in FIG. 6B is an example using a first plate body W having a flat first contact surface that does not have a stepped portion (except for excluding the first plate body W for convenience of explanation). The elements of are used in common.)
In this example, as shown in FIG. 6 (b), the left and right sides of the first plate body W and the second plate body 35 that contact the fork 40 due to local deflection of the first plate body W are provided. A region S having a high surface pressure (a range indicated by hatching in FIG. 6B) is generated only in the vicinity of the pressed portion T. For example, a region having a low surface pressure is generated in the vertical direction.
That is, it can be said that a significant difference in surface pressure occurs in a poorly balanced state on the contact surface between the first plate body W and the second plate body 35 that do not include a stepped portion.
Thus, when compared with the first plate body W of this comparative example, the first plate body 30 having the stepped portion 34 has a significant difference in the contact surface between the first plate body 30 and the second plate body 35. A certain surface pressure is distributed in a well-balanced manner.

Since the significant difference in the contact pressure between the contact surfaces of the first plate body 30 and the second plate body 35 is distributed in a well-balanced manner, there is a significant difference in contact pressure between the friction surfaces of the brake disks 25 and the stators 26. Even if it exists, it is in a well-balanced state.
In a state in which a significant difference in surface pressure is distributed in a balanced manner between the friction surfaces of the brake disks 25 and the stators 26, a sufficient braking force for the rotating shaft can be obtained.
In this embodiment, since the operation lever is a toggle-type lever, when the operation lever is operated so as to be on the braking side, a predetermined pressing force or more is set to act on the first plate body 30 through the fork 40. ing.

When releasing the braking state of the parking brake device, the pressing of the fork 40 against the first plate body 30 is released by operating the operation lever to the release side.
For this reason, the 1st plate body 30 which received the press of the fork 40 and was deform | transformed into flat form returns to the original curved form by elasticity.
Further, the first plate body 30 is returned to the original position by receiving the urging force of the return spring 42, and the brake disk 25 and the stator 26 are moved in the axial direction on the fork 40 side by receiving the pressure of the lubricating oil. Return to position.

The parking brake device according to the embodiment of the present invention has the following effects.
(1) In the braking state, the first plate body 30 is pressed by the fork 40, the first plate body 30 and the second plate body 35 are pressed against each other, and the second plate body 35 and the brake disc 25 are pressed against each other. . Since the step portion 34 is formed at the boundary between the end contact portion 33a and the intermediate contact portion 33b, the pressing force at which the fork 40 is locally concentrated is applied to the pressed portion 32a of the first plate body 30. Even in this case, the pressing force can be mainly dispersed in the vicinity of the step portion 34. That is, during braking, even if there is a significant difference in surface pressure between the first contact surface 33 and the second contact surface 36, the surface pressure is dispersed so that the braking force against the rotation shaft does not decrease.
(2) Since the fork 40 of the plate pressing mechanism 38 presses the pressed portion 32a of the pressed surface 32 of the first plate body 30 in the axial direction of the brake disc 25, the fork 40 presses the pressed portion 32a, and the fork The pressure contact between the piston plate 29 and the brake disc 25 is possible only by increasing the pressing force of 40. Accordingly, it is possible to use the plate pressing mechanism 38 that applies a large pressing force locally.

(3) Since the first plate body 30 provided with the step portion 34 on the first contact surface 33 is used, compared with the case where the plate thickness of the first plate body 30 is increased, the axial direction of the parking brake device is increased. Even when the space in the axial direction is limited and the disc contact surface 37 between the piston plate 29 and the brake disc 25 has a significant difference in surface pressure during braking, the rotational shaft The surface pressure is distributed in a well-balanced manner so that the braking force against is not reduced. Further, an increase in the weight of the parking brake device can be prevented.
(4) The intermediate contact portion 33b and the stepped portion 34 in the first plate body 30 can be simultaneously formed relatively easily by cutting, for example.

  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 end contact part 33a, the intermediate contact part 33b, and the step part 34 are formed on the first contact surface 33 of the first plate body 30 in the piston plate 29. For example, FIG. You may use the piston plate 51 shown to a) and FIG.7 (b). In the piston plate 51 according to this alternative example, the pressing surface 54 and the first contact surface 55 of the first plate body 52 are flat surfaces without a stepped portion, and the end portions of the second contact surface 58 of the second plate body 56 are end portions. A contact portion 58a, an intermediate contact portion 58b, and a step portion 59 are formed.
In this case, when the fork 40 is pressed against the pressed surface 72 of the first plate body 52 during braking, as shown in FIG. 7B, the first plate body 52, the second plate body 56, and the second plate body. 56 and the brake disc 25, and the brake disc 25 and the stator 26 are in pressure contact with each other, and the first plate body 52 is elastically deformed at a portion corresponding to the intermediate contact portion 58b.
At this time, since a region having a high surface pressure around the stepped portion 59 is generated for each stepped portion 77, most of the pressing force acts on the second plate body 56 through the four regions.
That is, the four step portions 34 provided on the second plate body 56 are configured so that the braking force on the rotating shaft does not decrease even if there is a significant difference in surface pressure on the contact surface with the first plate body 52. Disperse the surface pressure.

In the above-described embodiment, the specific radial direction in which the end contact portion 33a and the intermediate contact portion 33b in the first contact surface 33 are formed is the upper and lower radial direction, but the specific radial direction is Not specified in the vertical and horizontal directions.
Furthermore, in the above-described embodiment, the wall portion connecting the end contact portion 33a and the intermediate contact portion 33b in the stepped portion 34 is parallel to the axis A, and the contact portions 33a and 33b are formed with the wall portion. Although the corner portion is a right angle, the wall portion may be inclined or the corner portion may be provided with a chamfered portion by a curve or a straight line.

In the above embodiment, the stepped portions 34 are formed so as to be parallel to each other. For example, as shown in FIG. 8, a first plate body 61 having a radial stepped portion 62 may be used.
In this case, the shape of the end contact part 63a and the intermediate contact part 63b on the first contact surface 63 is different from that of the above embodiment by forming the radial step part 62.
In this case as well, as in the above-described embodiment, even if there is a significant difference in surface pressure between the contact surfaces of the first plate body 61 and the second plate body (not shown), the braking force on the rotating shaft is reduced. The surface pressure is dispersed so as not to occur.

  In the above-described embodiment, the pressing member of the plate pressing mechanism 38 includes the swinging fork 40 using the fulcrum shaft. However, the pressing member is not limited to the swinging fork 40, and the pressing member advances and retreats in the axial direction. A member may be sufficient, and the kind and structure in particular will not be ask | required especially if it is a press member which presses the to-be-pressed part 32a in the 1st plate body 30 to the axial direction of a rotating shaft.

In the above embodiment, a dedicated member is used for the second plate body 35, but the stator 26 may be used as the second plate body.
In this case, since the end contact portion 33a and the intermediate contact portion 33b having a boundary due to the stepped portion 34 of the first plate body 30 are pressed against each other, the friction surface of the stator 26 is formed of a durable material. Is preferred.
By using the stator 26 as the second plate body, it is not necessary to prepare a dedicated second plate body.

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 provided, a plane, and a side surface. It is a perspective view of the 1st plate object concerning the embodiment of the present invention. It is a principal part side view explaining operation | movement of the parking brake apparatus which concerns on embodiment of this invention, Fig.5 (a) shows the state by which the braking state was cancelled | released, FIG.5 (b) shows a braking state. FIGS. 6A and 6B are explanatory views for explaining correction of a significant difference in surface pressure in a piston plate, FIG. 6A is a front view of a first plate body according to the embodiment, and FIG. 6B is a first plate according to a comparative example. It is a front view of a body. FIG. 7A is a side view of a piston plate according to another example, FIG. 7A shows a state where the braking state is released, and FIG. 7B shows a braking state. It is a rear view of the 1st plate body which shows another example of a level difference part.

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, 52 61 First Plate Body 32, 54 Pressed Surfaces 32a, 54a Covered Press part 33, 55, 63 1st contact surface 33a, 58a, 63a End part contact part 33b, 58b, 63b Intermediate contact part 34, 59, 62 Step part 35, 56 2nd plate body 36, 58 2nd Contact surface 37, 60 Disc contact surface 38 Plate pressing mechanism 39 Support shaft 40 Fork 40a Pressing portion 41 Tilt lever A Output shaft axis

Claims (2)

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 is composed of a first plate body and a second plate body that are continuously provided in the axial direction,
The first plate body has a pressed surface that is pressed by the plate pressing mechanism, and a first contact surface that contacts the second plate body,
The second plate body has a disk contact surface that is in pressure contact with the brake disk, and a second contact surface that faces the first plate body,
The first contact surface or the second contact surface is between a pair of end contact portions formed near the outer periphery in a specific radial direction of the corresponding contact surface and the pair of end contact portions. Having an intermediate abutment formed,
The end contact portion is a flat surface perpendicular to the axial direction,
A stepped portion for setting the end contact portion closer to the brake disc than the intermediate contact portion is formed at a boundary between the end contact portion and the intermediate contact portion .
The pressed surface has a pressed portion that comes into contact with the plate pressing mechanism,
The pressed portion is a parking brake device according to claim Rukoto is set at a position corresponding to the center abutting part. The parking brake device according to claim 1, wherein the step portion is a pair of upper and lower parallel steps on the first contact surface .

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