Band brake device and drum with blades

Abstract

To provide a band brake device which achieves improvement of heat radiation performance while having a simple structure.SOLUTION: A band brake device includes: a drum fixed to a hub which rotates with a wheel, including an annular bottom part which integrally rotates with the hub and a cylindrical outer wall part erected from an outer periphery of the bottom part, having a shape which is open at an upper part; a housing fixed to a vehicle body of a vehicle and having an enclosure portion which has a circular space part at an outer side of an outer peripheral surface of the outer wall part, encloses the drum, and has a cylindrical bowl shape; an arc shaped belt-like band which is provided at the housing and arranged in the circular space part so as to enclosure an outer peripheral surface of the drum. The belt-like band makes pressure contact with the outer peripheral surface of the drum to cause friction and brake rotation of the hub. The band brake device includes a plurality of blades which are provided in the drum and radially arranged in a radial direction from a rotation center to the outer wall part at intervals in a circumferential direction of the bottom part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a band brake device, a vaned drum, and a vaned base plate. [Background technology]

[0002] Conventionally, band brake devices have often been used as brakes for the rear wheels of bicycles, which are considered to be light bicycles used in daily life, such as mamachari and city bicycles. An example of a band brake device is disclosed in Patent Document 1.

[0003] Fig. 6 is an explanatory diagram of the structure of a typical band brake device. A conventional band brake device 101 has a drum 104 fixed to a hub that rotates together with the rear wheel, a housing 108 fixed to a bicycle frame 106 and having a surrounding portion 108A that has a circular space outside an outer circumferential surface 104A of the drum 104 and surrounds the drum 104, and a band-like band 110 disposed in a circular space 108B inside the housing 108 so as to surround the outer circumferential surface 104A of the drum 104. The reference numeral 102 denotes an axle.

[0004] Then, by operating a brake lever 112 connected to a brake handle (not shown) via a brake wire (not shown) in the direction A, the right side of the rotation center 114 is lifted (the left side of the rotation center 114 is not joined to the right side and is fixed to the frame, so it remains immobile even if the right side of the rotation center 114 is lifted), and the band 110 presses against the outer circumferential surface 104A of the drum 104. This generates friction between the band 110 and the outer circumferential surface 104A of the drum 104, thereby braking the rotation of the hub. Reference numeral 102 denotes an axle.

[0005] Furthermore, when the bicycle is shipped, a brake gap adjustment operation is performed in which an operator visually checks the distance between the outer peripheral surface 104A of the drum 104 and the band 110 through a side opening of the circular space, and uses the adjustment bolt 116 to appropriately adjust the gap distance between the band 110 and the outer peripheral surface 104A of the drum 104 to obtain an appropriate brake gap. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 61-22937, Summary of the Invention [Problem to be solved by the invention]

[0007] The conventional band brake device shown in Patent Document 1 has a problem that frictional heat generated when friction is generated by pressing the outer circumferential surface of the drum with a belt-shaped band tends to accumulate inside the drum, and has poor heat dissipation. This causes a problem of unstable braking performance. For example, when it is necessary to keep applying the brakes, such as when going down a long slope, the brakes heat up and the braking effect becomes poor.

[0008] Incidentally, the Japan Bicycle Association has established voluntary "Bicycle Safety Standards" with the aim of providing bicycles that are safe, secure, and environmentally friendly for cyclists, and bicycles that pass these standards can be affixed with the BAA mark. The deterioration of braking performance due to the above-mentioned friction is an undesirable state in light of the "Bicycle Safety Standards," and there is also the problem that the durability of the band brake device itself is reduced due to frictional heat.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide a band brake device having improved heat dissipation while having a simple structure. It is also an object of the present invention to provide a vaned drum and a vaned base plate. [Means for solving the problem]

[0010] As a result of intensive research by the present inventors to solve the above problems, they have found that the above problems can be solved by the following configuration.

[0011] [1] A band brake device comprising: a drum fixed to a hub that rotates with a wheel, having an annular bottom that rotates integrally with the hub, and a cylindrical outer wall rising from the outer periphery of the bottom, with an open top; a housing fixed to the vehicle body of a vehicle, having a cylindrical bowl-shaped surrounding portion that has a circular space outside the outer periphery of the outer wall and surrounds the drum; an arc-shaped band provided on the housing and arranged in the circular space to surround the outer periphery of the drum; and the band presses against the outer periphery of the drum to generate friction and brake the rotation of the hub, the band brake device comprising a plurality of vanes provided inside the drum and arranged radially in a radial direction from the center of rotation to the outer wall at intervals around the circumferential direction of the bottom. [2] The band brake device described in [1], wherein the blades are mounted on a circular base plate, and the base plate is fixed to the bottom so as to be approximately concentric with the drum. [3] The band brake device described in [2], wherein the blade is formed by cutting a portion of the base plate and raising the cut portion. [4] The drum has a cylindrical inner wall portion rising from the inner periphery of the bottom portion, The hub is inserted into a central hole in the bottom of the drum and supported by the inner surface of the inner wall portion, and the blades are positioned so as to be approximately in contact with at least one selected from the group consisting of the outer surface of the inner wall portion and the inner surface of the outer wall portion.A band brake device as described in [1]. [5] A band brake device as described in [4], wherein the blades are provided from the outer peripheral surface of the inner wall portion to the inner peripheral surface of the outer wall portion. [6] The band brake device described in [1], wherein the drum has a plurality of holes arranged at intervals in a substantially concentric pattern around the circumferential direction of the bottom. [7] A vaned drum used in a band brake device, comprising: a circular bottom portion fixed to a hub that rotates with the wheel and rotates integrally with the hub; and a cylindrical outer wall portion rising from the outer periphery of the bottom portion, with an open top, and a plurality of vanes disposed inside the bottom portion and radially arranged at intervals around the circumference of the bottom portion from the center of rotation to the outer wall portion. [8] A base plate with blades that is attached to the inside of a drum of a band brake device, comprising: an annular base plate; and a plurality of blades that are provided on the annular base plate and are arranged radially from the center to the outer periphery at intervals in the circumferential direction, the drum being fixed to a hub that rotates with the wheel, having an annular bottom that rotates integrally with the hub, and a cylindrical outer wall rising from the outer periphery of the bottom, and having an open shape at the top, the base plate being used inside the drum and fixed to the bottom so as to be approximately concentric with the drum. Effect of the Invention

[0012] According to the present invention, there is provided a band brake device having improved heat dissipation properties despite its simple structure. Also, according to the present invention, there is provided a vaned drum and a vaned base plate. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is an exploded perspective view of the bladed drum of the first embodiment. [Diagram 2] FIG. 11 is a bottom view of the band brake device of the second embodiment. [Diagram 3] FIG. 11 is a plan view of the band brake device of the second embodiment. [Figure 4] FIG. 11 is a perspective view of the bladed drum of the third embodiment. [Diagram 5] FIG. 11 is a perspective view of the bladed drum of the fourth embodiment. [Figure 6] FIG. 1 is an explanatory diagram of a conventional drum brake device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0015] The embodiment shown below is an example that embodies the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the materials, shapes, structures, and arrangements of the components to the following embodiment. The drawings are schematic. Therefore, the relationship and ratio between thickness and planar dimensions may differ from the actual ones, and the relationship and ratio between dimensions may differ between the drawings.

[0016] Example 1 1 is an exploded perspective view of a bladed drum according to a first embodiment of the present invention. The bladed drum 100 comprises a drum 12 and a bladed base plate 10 fixed to a bottom portion 12H of the drum 12 by screws 48.

[0017] The drum 12 includes an annular bottom 12H having a hole 12F in the center, a cylindrical outer wall 12A rising from the outer periphery of the bottom 12H, and a cylindrical inner wall 12K rising from the inner periphery of the bottom 12H. The outer wall 12A and the inner wall 12K are concentrically arranged with respect to the center of the hole 12F. The upper part (top surface side) of the drum 12 is open (open cylindrical).

[0018] An inner peripheral surface 12E of the inner wall portion 12K is provided with a thread groove (not shown) (female thread structure), and a hub (male thread structure) with a thread groove on the outer periphery is inserted and fixed. Therefore, the bladed drum 100 rotates integrally with the hub (not shown).

[0019] The bladed base plate 10 is provided with a plurality of blades 10C formed by cutting a part of the main body 10A, which is a circular plate material, and raising the cut part. The blades 10C are radially arranged in the radial direction from the center to the outer periphery at intervals in the circumferential direction. A hole 10F having a larger diameter than the outer periphery of the inner wall portion 12K of the drum 12 is provided in the center of the main body 10A, and the outer periphery 12L of the inner wall portion 12K and the inner periphery 10E of the hole 10F are concentrically fitted together in a state where they are substantially in contact with each other.

[0020] Through holes 10D are arranged at intervals in the circumferential direction in the main body 10A of the vaned base plate 10. When the vaned base plate 10 and the drum 12 are combined, the bottom 12H has through holes 12D at positions corresponding to the through holes 10D, and screws 48 are screwed into these through holes 12D so that the vaned base plate 10 is fixed to the bottom 12H and rotates together with the drum 12.

[0021] A through hole 10B having a diameter larger than that of the through hole 10D is provided in the main body 10A of the bladed base plate 10. The through hole 10B is large enough to allow the fingers of a mechanic or the like to be inserted therein, and specifically has a diameter of 1 to 3 cm. Similarly, a through hole 12C having approximately the same diameter is provided at a corresponding location on the bottom portion 12H of the drum 12. When the drum 12 and the bladed base plate 10 are placed together, the through holes 10B and 12C overlap, allowing the insertion of tools, etc. This allows the tip of a general-purpose drum tool to be inserted into this portion when removing the bladed drum 100 attached to the housing (described later) or when removing the bladed drum 100 fixed to the hub, making it easier to perform the work.

[0022] Further, six through holes 12G having a diameter slightly smaller than that of the through holes 12C are provided at intervals in the circumferential direction in a bottom portion 12H of the drum 12. The through holes 12G serve as air circulation ports. When the bladed drum 100 rotates, an air flow is generated inside the bladed drum 100 by the blades 10C of the bladed base plate 10. This air flow cools the frictional heat generated during braking. Furthermore, the through holes 12G make it easier to exhaust air from inside the bladed drum 100 and to draw air from the outside, thereby further improving the cooling effect.

[0023] In this embodiment, the vanes 10C are formed by cutting the main body 10A of the vaned base plate 10 and then bending it up. This reduces the number of parts, and an effective cooling effect can be obtained at low cost. Furthermore, the vaned base plate 10 can be attached to the drum of a conventional drum brake device with only simple processing (making screw holes), so it can be easily applied to bicycles that are already in widespread use. The blades 10C of the bladed base plate 10 are not limited to being formed by cutting into the main body 10A, but may be formed integrally with the main body 10A or may be added by welding, etc. Furthermore, the shape and number of the blades are not limited.

[0024] In this embodiment, the bladed drum 100 is formed by fixing the bladed base plate 10 to the drum 12. However, the bladed drum of the present invention is not limited to the above configuration, and it is sufficient that a plurality of blades are arranged inside the drum in a radial direction from the center of rotation toward the inner peripheral surface 12J of the outer wall portion 12A. For example, the drum and the blades may be integrally molded. The shape of the blades may be a so-called axial fan shape or a centrifugal fan shape.

[0025] Example 2 Next, a description will be given of the overall configuration of the band brake device of the present invention, which is equipped with the vaned drum 100. Fig. 2 is a bottom view of the band brake device of the second embodiment of the present invention. Fig. 3 is a plan view of the band brake device.

[0026] The band brake device 200 is mainly composed of a vaned drum 100, a housing 14, a band 16, and an adjustment bolt 18. The band 16 presses against the outer peripheral surface 12B of the outer wall portion 12A of the drum 12, which rotates integrally with a hub that rotates together with a wheel (not shown), for example, to generate friction and apply a brake to the rotation of the hub. The hub rotates together with the wheel.

[0027] The band brake device 200 is often used as a brake for the rear wheel of a bicycle, but it can also be used as a brake for other vehicles, such as wheelchairs and baby carriages, and is not limited to bicycles. However, in the following explanation, a bicycle (not shown) will be used as an example of a vehicle to which the band brake device 200 is attached, and the band brake device 200 of the present invention will be attached to the hub of the rear wheel of the bicycle.

[0028] The mechanism by which the band 16 presses against the outer peripheral surface 12B of the drum 12 is not essential to the present invention and will not be described in detail, but for example, the lever mechanism and brake wire connected to a brake handle (not shown) described in the prior art in Fig. 8 can be used. Note that in this embodiment, an example will be described in which a crank member 28 is used as the lever mechanism.

[0029] The drum 12 is formed in a generally cylindrical bowl shape with an outer wall portion 12A having a cylindrical outer peripheral surface 12B. That is, the outer wall portion 12A of the drum 12 protrudes toward the back of the paper in Fig. 2, and protrudes toward the front of the paper in Fig. 3. The outer wall portion 12A of the drum 12 formed in a generally cylindrical bowl shape has a small thickness that is slightly larger than the width of the band 16.

[0030] A hole 12F for fixing to a hub is formed in the center of the bottom 12H of the drum 12, and a female screw is engraved in the hole 12F. As a result, the drum 12 is fixed by screwing into a male screw member (not shown) provided on the hub, and rotates integrally with the hub.

[0031] The housing 14 is composed of a surrounding portion 14C formed in a generally cylindrical bowl shape by an arc-shaped outer peripheral frame 14A and a housing side plate 14B, and a support portion 14D extending from the surrounding portion 14C in a generally U-shaped plate shape. That is, the arc-shaped outer peripheral frame 14A of the housing 14 protrudes toward the front side of the paper in Fig. 2, and protrudes toward the back side of the paper in Fig. 3. The surrounding portion 14C is composed of the arc-shaped outer peripheral frame 14A and the disk-shaped portion of the housing side plate 14B, and the support portion 14D is composed of the generally U-shaped plate-shaped portion of the housing side plate 14B.

[0032] A through hole 14E that passes through to the axle is formed in the center of the housing side plate 14B of the surrounding portion 14C of the housing 14. Also, a fixing hole 14F for fixing to the bicycle frame is formed in the support portion 14D.

[0033] The arc-shaped outer peripheral frame 14A forming the surrounding portion 14C of the housing 14 is formed with a larger diameter than the outer wall portion 12A of the drum 12. When the drum 12 and the housing 14 are attached to the bicycle and assembled, the housing 14 has a circular space 14G outside the outer peripheral surface 12B of the drum 12 and surrounds the drum 12. In this case, the drum 12, which is substantially cylindrical and bowl-shaped, and the surrounding portion 14C of the housing 14, which is substantially cylindrical and bowl-shaped, are aligned in a facing orientation. The support portion 14D of the housing 14 is supported so as to be freely swingable via a swing shaft 32 provided at the fulcrum portion 28A, which is the swing center of the crank member 28.

[0034] The band 16 is disposed in an arc shape on the inner surface side of the arc-shaped outer peripheral frame 14A of the housing 14. As a result, when the drum 12 and the housing 14 are attached to the bicycle and assembled, the band 16 is disposed in an arc shape so as to surround the outer peripheral surface 12B of the drum 12. One end of the band 16 is fixed to one end of the arc-shaped outer peripheral frame 14A by a fixing pin 34, and the other end of the band 16 is connected to a connecting pin 36 provided at the application point portion 28B of the crank member 28. In addition, a connecting bolt 38 for connecting one end of a brake wire (not shown) is provided at the force point portion 28C of the crank member 28.

[0035] The belt-shaped band 16 is composed of a belt-shaped metal plate 16A made of a leaf spring material and a belt-shaped friction member 16B (e.g., a belt-shaped rubber plate) affixed to the inner side of the belt-shaped metal plate 16A (the side facing the outer peripheral surface 12B of the drum 12).

[0036] As a result, the band 16 is curved in an arc along the inner surface of the arc-shaped outer peripheral frame 14A of the housing 14, and a biasing force acts outward (in a direction away from the outer peripheral surface 12B of the drum 12).

[0037] Therefore, when the bicycle is not normally braked, a gap is formed between the band 16 and the outer circumferential surface 12B of the drum 12. This means that the band 16 does not impede the rotation of the drum 12 which rotates together with the hub body. Then, by applying the brakes to the bicycle and pulling the force point 28C of the crank member 28 in the X direction with a brake wire (not shown), the crank member 28 swings around the swing shaft 32 (fulcrum 28A) as the swing center, and the action point 28B of the crank member 28 swings in the direction of arrow Y.

[0038] As a result, the band 16 is pulled in a direction in which the curvature of the band 16 decreases, so that the frictional band 16B of the band 16 presses against the outer circumferential surface 12B of the drum 12. As a result, friction occurs between the band 16 and the rotating drum 12, and the bicycle is braked.

[0039] Frictional heat generated during braking is discharged to the outside through the through holes 12C, 12G, etc. by the rotation of the blades 10C of the bladed drum 100 (the bladed drum 100 rotates when traveling). This cools the inside of the band brake device 200, maintains the braking performance, and improves the durability of the band 16, etc.

[0040] In the band brake device 200, the vaned drum 100 is fixed so that the drum 12 faces outward (so that the vanes 10C are difficult to see from the outside). However, this may be reversed and the blades 10C may be fixed in a direction that is visible from the outside, in other words, the mounting direction of the bladed drum 100 in Fig. 2 may be reversed. In this case, the cooling effect is likely to be further improved.

[0041] A plurality of adjustment bolts 18 are provided on the arc-shaped outer peripheral frame 14A of the housing 14. In this embodiment, an example in which two adjustment bolts 18 are provided will be described. The two adjustment bolts 18 are supported in a state where they are screwed into female screw holes formed at a predetermined interval near the center of the arc of the arc-shaped outer peripheral frame 14A.

[0042] That is, by turning the two adjustment bolts 18 to adjust the amount of projection from the arc-shaped outer peripheral frame 14A toward the drum 12, the tips of the adjustment bolts 18 come into contact with and press against the outer surface of the belt-shaped band 16. The adjustment bolts 18 are screwed into the arc-shaped outer peripheral frame 14A so that their tips face the central axis of the axle.

[0043] It is preferable that the installation positions and specified spacing of the two adjustment bolts 18 on the arc-shaped outer frame 14A of the housing 14 be such that when the two adjustment bolts 18 press against the outside of the strip band 16, the gap distance of the entire strip band 16 relative to the outer surface 12B of the drum 12 is approximately uniform.

[0044] This makes it possible to evenly adjust the gap distance between the strip-shaped friction member 16B of the strip-shaped band and the outer peripheral surface 12B of the drum 12 by pressing two points on the outer surface of the strip-shaped band 16 toward the drum 12 with two adjustment bolts 18.

[0045] Example 3 FIG. 4 is a perspective view of a bladed drum according to a third embodiment of the present invention. The bladed drum 300 includes a bladed base plate 40 fixed inside the drum 12. The bladed base plate 40 has a shape substantially similar to that of the bladed base plate 10 of the first embodiment, but differs in that the outer edge portions 40G of the blades 40C are configured to be in substantial contact with the inner peripheral surface 12J of the outer wall portion 12A of the drum 12.

[0046] The contact of edge portions 40G of blades 40C with inner peripheral surface 12J makes it easier to efficiently generate airflow for exchanging air between the inside and outside of drum 12 when bladed drum 300 rotates. Airflow is less likely to escape from edge portions 40G of blades 40C, making it easier to generate airflow in the desired direction. The edge portion 40G and the inner peripheral surface 12J may be configured to be in close contact with each other, but may have a certain degree of gap therebetween because high precision is required in processing the vaned base plate 40. In this case, the gap may be filled with a caulking agent or the like.

[0047] In the bladed base plate 40, the edge portions 40G of the blades 40C are configured to be in substantial contact with the inner peripheral surface 12J. The inner edge portions 40H are configured to be spaced apart from the outer peripheral surface 12L by a certain gap. This has the advantage that the blades 40C can be formed by cutting from a single base plate. Since the blade 40C can be formed from a single base plate, the number of parts is small and the device can be easily attached to existing bicycle drums. In this embodiment, the edge portion 40G is configured to be in almost contact with the inner circumferential surface 12J, but the same effect as described above can be obtained by configuring only the inner edge portion 40H to be in almost contact with the outer circumferential surface 12L.

[0048] Example 4 FIG. 5 is a perspective view of a bladed drum according to a fourth embodiment of the present invention. The bladed drum 400 is similar to the bladed drum 300 of the third embodiment in that it includes a bladed base plate 40 fixed inside the drum 12. The bladed drum 400 has an auxiliary blade 60 that extends the blade 40C to the inner periphery side. The auxiliary blade 60 is provided from the edge portion on the inner periphery side to the outer periphery surface 12L.

[0049] In the case of Fig. 5, the auxiliary blade 60 is formed of transparent plastic and is attached to the surface of the blade 40C. The blade 40C extended to the inner peripheral side by the auxiliary blade 60 is provided from the outer peripheral surface 12L to the inner peripheral surface 12J, and the airflow leaking from the edge portion during rotation is further suppressed, enabling more efficient cooling. The material of the auxiliary blade 60 is not limited to plastic. It may be metal or the like.

[0050] In this embodiment, the blade 40C is provided so as to be in substantial contact with the inner peripheral surface 12J, and is extended inwardly by the auxiliary blade 60. In addition to the above, the blade may be provided so as to be in substantial contact with the outer peripheral surface 12L, and may be extended outwardly by the auxiliary blade so as to reach the inner peripheral surface 12J. With the above-mentioned configuration, the vaned base plate 40 can be made from a single annular plate, which is less expensive and allows for more efficient cooling with the auxiliary vanes. This configuration is preferable because vanes can be easily added to existing bicycle drums. As already explained, the blades may be formed integrally with the drum, or may be disposed so as to extend from the outer peripheral surface 12L to the inner peripheral surface 12J. [Explanation of symbols]

[0051] 10 Base plate 12 Drums 14 Housing 16 Belt 18 Adjustment bolt 28 Crank parts 32 Swing axis 34 Fixing pin 36 Connecting pin 38 Connecting bolt 40 Base Plate 48 Bis 60 Auxiliary blade 100, 300, 400 Bladed drum 102 Axle 110 Belt 112 Brake lever 114 Rotation center 116 Adjustment bolt 200 Band brake device

Claims

1. a drum having an open top, the drum having an annular bottom portion fixed to a hub that rotates together with the wheel and rotates integrally with the hub, and a cylindrical outer wall portion rising from the outer periphery of the bottom portion; a housing fixed to a vehicle body of a vehicle, the housing having a cylindrical bowl-shaped surrounding portion having a circular space outside an outer circumferential surface of the outer wall portion and surrounding the drum; a circular arc-shaped band provided in the housing and disposed in the circular space so as to surround the outer circumferential surface of the drum; In a band brake device, the band presses against the outer circumferential surface of the drum to generate friction and brake the rotation of the hub, A band brake device comprising a plurality of blades provided inside the drum and arranged radially in a radial direction from the center of rotation toward the outer wall portion at intervals around the circumferential direction of the bottom portion.

2. 2. The band brake apparatus of claim 1, wherein the vanes are mounted on an annular base plate, the base plate being fixed to the bottom so as to be substantially concentric with the drum.

3. The band brake device according to claim 2 , wherein the vanes are formed by cutting a portion of the base plate and raising the cut portion.

4. The drum has a cylindrical inner wall portion rising from the inner periphery of the bottom portion, The hub is inserted into a hole in the center of the bottom of the drum and is supported by an inner circumferential surface of the inner wall. The band brake device according to claim 1 , wherein the vane is arranged so as to be substantially in contact with at least one selected from the group consisting of an outer peripheral surface of the inner wall portion and an inner peripheral surface of the outer wall portion.

5. The band brake device according to claim 4 , wherein the vanes are provided from an outer peripheral surface of the inner wall portion to an inner peripheral surface of the outer wall portion.

6. 2. The band brake apparatus of claim 1, wherein the drum has a plurality of holes spaced apart from one another in a generally concentric pattern around the circumference of the bottom portion.

7. A vaned drum used in a band brake device, The wheel has an annular bottom portion that is fixed to a hub that rotates together with the wheel and rotates integrally with the hub, and a cylindrical outer wall portion that rises from the outer periphery of the bottom portion, and has an open top; The bladed drum has a plurality of blades disposed inside the bladed drum and arranged radially in a radial direction from a center of rotation toward the outer wall portion at intervals in a circumferential direction of the bottom portion.

8. A vaned base plate attached to the inside of a drum of a band brake device, The rotor includes an annular base plate and a plurality of blades provided on the annular base plate and arranged radially from a center to an outer periphery at intervals in a circumferential direction, The drum is fixed to a hub that rotates together with the wheel, has an annular bottom portion that rotates integrally with the hub, and has a cylindrical outer wall portion that rises from the outer periphery of the bottom portion, and has a shape with an open top, The base plate is a vaned base plate that is used by being fixed to the bottom inside the drum so as to be approximately concentric with the drum.

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