Speed suppression device and vehicle

Abstract

To provide a speed suppression device which can be made inoperative, and a vehicle equipped with the speed suppression device.SOLUTION: The speed suppression device 1 of the embodiment includes the brake drum 11 that is provided integrally with the axle 2 and has the cylindrical portion 11b, the brake shoes 23 that are displaced by receiving centrifugal forces generated according to the rotation of the wheel and come into contact with the inner peripheral surface of the cylindrical portion 11b to suppress the rotation of the wheel, and the limiting protrusion 25d that limits the displacement of the brake shoes 23.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a speed control device and a vehicle. [Background technology]

[0002] Conventionally, there have been known vehicles, such as walkers, used to assist users in walking, that are equipped with a speed control device (speed control wheel) that controls the rotational speed of the wheels (see, for example, Patent Document 1).The speed control device includes a brake drum integrally attached to the wheel, a gear plate rotatably attached to the axle that supports the wheel, a brake shoe oscillatably attached to the gear plate, a compression spring (elastic member) that comes into contact with the brake shoe and applies an elastic force to the brake shoe, and a cam that adjusts the pressing force of the compression spring on the brake shoe.

[0003] With this configuration, when the wheel rotates, centrifugal force acts on the brake shoe. This causes the brake shoe to swing against the spring force of the compression spring and press against the inner circumferential surface of the brake drum. The frictional resistance that occurs at this time prevents the wheel from rotating faster than desired. In other words, the speed suppression device operates in response to the rotation of the wheel. The rotational speed of the wheel at which the speed control device operates is controlled by a compression spring and a cam. In other words, when the cam increases the pressing force of the compression spring against the brake shoe, the brake shoe becomes less likely to oscillate. In this way, it is possible to change the activation timing of the speed control device for each wheel rotational speed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-59838 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in recent years, some users of vehicles equipped with speed control devices have been requesting that the speed control devices remain inactive. However, in the above-mentioned conventional technology, although it is possible to change the activation timing of the speed control device for each wheel rotation speed, there is a problem in that it is difficult to deactivate the speed control device.

[0006] The present invention provides a speed suppression device that can be deactivated and a vehicle equipped with the speed suppression device. [Means for solving the problem]

[0007] A speed control device according to one embodiment of the present invention is a speed control device that controls the rotational speed of a rotating body supported rotatably on a shaft portion, and comprises a brake drum that is integrally formed with the shaft portion and has a cylindrical portion, a brake shoe that displaces in response to centrifugal force generated in response to the rotation of the rotating body and contacts the inner surface of the cylindrical portion, thereby controlling the rotation of the rotating body, and a limiting portion that limits the displacement of the brake shoe.

[0008] With this configuration, the limiting portion can limit the displacement of the brake shoe, preventing the brake shoe from contacting the inner circumferential surface of the cylindrical portion regardless of the rotational speed of the rotating body, thereby disabling the speed suppression device.

[0009] In the above configuration, the brake shoe is equipped with a compression spring that contacts the brake shoe and applies an elastic force to control the amount of displacement of the brake shoe, a support portion that is provided on the opposite side of the compression spring from the brake shoe and supports the compression spring, and a shift portion that displaces the support portion in the compression direction of the compression spring, thereby reducing the pressing force of the brake shoe against the cylindrical portion, and displaces the support portion in the extension direction of the compression spring, thereby increasing the pressing force of the brake shoe against the cylindrical portion, and the limiting portion includes a convex portion that protrudes from the support portion toward the brake shoe on the opposite side across the compression spring, and the convex portion contacts the brake shoe to prevent displacement of the brake shoe when the amount of displacement of the compression spring at the support portion in the compression direction reaches a certain amount.

[0010] In the above configuration, the brake shoe is equipped with a compression spring that contacts the brake shoe and applies an elastic force to control the amount of displacement of the brake shoe, a support portion that is provided on the opposite side of the compression spring from the brake shoe and supports the compression spring, and a shift portion that displaces the support portion in the compression direction of the compression spring, thereby reducing the pressing force of the brake shoe against the cylindrical portion, and displaces the support portion in the extension direction of the compression spring, thereby increasing the pressing force of the brake shoe against the cylindrical portion, and the limiting portion includes a convex portion that protrudes from the brake shoe towards the support portion on the opposite side of the compression spring, and the convex portion comes into contact with the support portion when the amount of displacement of the compression spring at the support portion in the compression direction reaches a certain amount, thereby preventing the displacement of the brake shoe.

[0011] In the above configuration, the brake shoe is equipped with a compression spring that contacts the brake shoe and applies an elastic force to control the amount of displacement of the brake shoe, a support portion that is provided on the opposite side of the compression spring from the brake shoe and supports the compression spring, and a shift portion that displaces the support portion in the compression direction of the compression spring, thereby reducing the pressing force of the brake shoe against the cylindrical portion, and displaces the support portion in the extension direction of the compression spring, thereby increasing the pressing force of the brake shoe against the cylindrical portion, and the limiting portion includes a convex portion provided on the shift portion, which contacts the brake shoe to prevent displacement of the brake shoe when the shift portion is operated so that the amount of displacement of the compression spring in the compression direction at the support portion reaches a certain amount.

[0012] In the above configuration, the shift portion includes a cam that rotates around the rotation axis of the rotating body and has the support portion disposed on its outer peripheral surface, and the convex portion is provided on the cam.

[0013] In the above configuration, the shift portion includes a cam that rotates around the rotation axis of the rotating body and has the support portion arranged on its outer peripheral surface, and an adjustment portion that rotates around another rotation axis parallel to the rotation axis of the rotating body and adjusts the rotation position of the cam, and the convex portion is provided on the adjustment portion.

[0014] In the above configuration, the rotating body includes a wheel provided on the body of the handcart.

[0015] A vehicle according to another aspect of the present invention comprises a vehicle body, a wheel rotatably supported on an axle of the vehicle body, and a speed control device that controls the rotational speed of the wheel, wherein the speed control device comprises a brake drum that is integral with the axle and has a cylindrical portion, a brake shoe that displaces in response to centrifugal force generated in response to rotation of the wheel and contacts the inner surface of the cylindrical portion, thereby controlling the rotation of the wheel, and a limiting portion that limits the displacement of the brake shoe.

[0016] This configuration allows the limiting portion to limit the displacement of the brake shoe, preventing the brake shoe from contacting the inner circumferential surface of the cylindrical portion regardless of the rotational speed of the wheel. Therefore, in a vehicle equipped with a speed control device, the speed control device can be deactivated. [Effects of the Invention]

[0017] The above-described speed suppression device and vehicle can deactivate the speed suppression device. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram illustrating the configuration of a walking vehicle according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a wheel and a speed suppression device according to an embodiment of the present invention, taken along the vertical direction and the vehicle width direction. [Figure 3] 1 is a plan view of a brake mechanism according to a first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 4] FIG. 2 is a plan view of a support portion according to the first embodiment of the present invention. [Figure 5] 1 is a plan view of a brake mechanism according to a first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 6] FIG. 4 is a plan view of a brake mechanism according to a first modified example of the first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 7] FIG. 10 is a plan view of a brake mechanism according to a second modified example of the first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 8] FIG. 10 is a plan view of a brake mechanism according to a third modified example of the first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 9] FIG. 10 is a plan view of a brake mechanism according to a fourth modified example of the first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 10] FIG. 10 is a plan view of a brake mechanism according to a fourth modified example of the first embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 11]FIG. 10 is a perspective view of a boss plate according to a second embodiment of the present invention. [Figure 12] FIG. 10 is an axial cross-sectional view of a boss portion according to a second embodiment of the present invention. [Figure 13] FIG. 10 is a plan view of a carrier plate according to a third embodiment of the present invention, as viewed from the outside in the vehicle width direction. [Figure 14] FIG. 14 is a cross-sectional view taken along line AA in FIG. [Figure 15] FIG. 11 is a plan view of a brake mechanism according to a fourth embodiment of the present invention when applying first-stage braking, as viewed from the outside in the vehicle width direction. [Figure 16] FIG. 10 is a plan view of a brake mechanism according to a fourth embodiment of the present invention when applying fourth-stage braking, as viewed from the outside in the vehicle width direction. [Figure 17] 10A and 10B are explanatory diagrams showing the behavior of a shift cam in the fourth embodiment of the present invention. [Figure 18] FIG. 11 is a plan view of a brake mechanism according to a fifth embodiment of the present invention, as viewed from the outside in the vehicle width direction. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, an embodiment of the present invention will be described with reference to the drawings.

[0020] <Vehicle> FIG. 1 is a schematic diagram of a wheelbarrow 101, which is a vehicle according to an embodiment. In the following description, the up-down direction refers to the wheelbarrow 101 when in use. The direction of travel of the wheelbarrow 101 when in use is referred to as the forward direction, and the direction opposite to the forward direction is referred to as the rearward direction. The direction perpendicular to the up-down direction and the front-to-rear direction is referred to as the width direction of the wheelbarrow 101.

[0021] The pushcart 101 is, for example, a walking frame used to assist a user in walking (hereinafter referred to as "walking frame 101"). 1, the walking vehicle 101 includes a body 102, a plurality of wheels 103 (for example, four in this embodiment) provided on the bottom of the body 102, and an operating unit 104 provided on the top of the body 102. The body 102 includes a lower frame 105 disposed on the bottom, and a vertical frame 106 extending upward from the lower frame 105.

[0022] The lower frame 105 includes a front frame 107 disposed at the front and extending in the vehicle width direction, and two side frames 108 extending rearward from both ends of the front frame 107 in the vehicle width direction. The multiple vertical frames 106 are arranged at the upper part of the front and rear parts of the side frames 108. An operating unit 104 is provided at the upper end of the vertical frames 106. The operating unit 104 is formed in a U-shape with an open rear end.

[0023] <Wheels> The plurality of wheels 103 provided on the vehicle body 102 have the same configuration. Therefore, in the following description, only one of the plurality of wheels 103 will be described, and a description of the other wheels 103 will be omitted.

[0024] FIG. 2 is a cross-sectional view of the wheel 103 and a speed control device 1 (described later) taken along the vertical direction and the vehicle width direction. 1 and 2, the wheels 103 are mounted on brackets 109 provided on the lower front and rear parts of the side frames 108. The wheels 103 include an axle 2 supported by the brackets 109, a disk-shaped wheel 111 rotatably supported on the axle 2, and a tire 112 attached to the outer circumferential surface of the wheel 111.

[0025] The axle 2 also serves as part of the speed suppression device 1, which will be described later. The axle 2 protrudes outward in the vehicle width direction from the bracket 109. The axle 2 is arranged so that the axial direction of the axle 2 coincides with the vehicle width direction. The wheel 111 is supported on the axle 2 via two bearings 113a, 113b (first bearing 113a, second bearing 113b) so as to be rotatable around the axle 2.

[0026] Of the two bearings 113a, 113b, the first bearing 113a is arranged closer to the inside in the vehicle width direction (closer to the bracket 109). Of the two bearings 113a, 113b, the second bearing 113b is arranged closer to the outside in the vehicle width direction than the first bearing 113a. The second bearing 113b is provided on the axle 2 via a bush 12 provided on the axle 2. In the following description of the wheel 103 and the speed suppression device 1 described later, the vehicle width direction may be referred to as the axial direction. The rotation direction of the wheel 103 is referred to as the circumferential direction. The radial direction of the axle 2, which is perpendicular to the axial and circumferential directions, is simply referred to as the radial direction.

[0027] The wheel 111 includes two disk-shaped wheel plates 114, 115 (first wheel plate 114 and second wheel plate 115) that overlap in the axial direction. Of the two wheel plates 114, 115, the first wheel plate 114, which is disposed on the bracket 109 side, has a disk-shaped first disk portion 116. A first outer flange portion 116b is integrally formed with an outer peripheral surface 116a of the first disk portion 116. The first outer flange portion 116b is disposed on the inner side of the first disk portion 116 in the vehicle width direction.

[0028] A first storage recess 117 that is open to the outside in the vehicle width direction is formed in the radial center of the first disk portion 116. The first storage recess 117 is formed in a circular shape when viewed in the axial direction. A first bearing housing 117b and a plurality of (for example, three in this embodiment) first planetary support pins 118 are integrally molded on a bottom wall 117a of the first storage recess 117.

[0029] The first bearing housing 117b is disposed at the center in the radial direction. The first bearing housing 117b is rotatably supported on the axle 2 via the first bearing 113a. The multiple first planetary support pins 118 protrude outward in the vehicle width direction from the bottom wall 117a. The multiple first planetary support pins 118 are disposed at equal intervals in the circumferential direction so as to surround the periphery of the first bearing housing 117b. Each first planetary support pin 118 constitutes a part of the speed suppression device 1, which will be described later.

[0030] Of the two wheel plates 114, 115, the second wheel plate 115, which is located on the outer side in the vehicle width direction, has a circular plate-shaped second disc portion 121. The outer diameter of the second disc portion 121 is the same as the outer diameter of the first disc portion 116. A second outer flange portion 121b is integrally formed with an outer circumferential surface 121a of the second disc portion 121. The second outer flange portion 121b is located on the outer side of the second disc portion 121 in the vehicle width direction.

[0031] A second storage recess 122 that is open on the inner side in the vehicle width direction is formed in the radial center of the second disk portion 121, and a bearing housing storage recess 126 that is open on the outer side in the vehicle width direction is formed. The second storage recess 122 is formed in a circular shape when viewed in the axial direction. The inner diameter of the second storage recess 122 is the same as the inner diameter of the first storage recess 117. A second bearing housing 122b is integrally molded with a bottom wall 122a of the second storage recess 122. The second bearing housing 122b is disposed in the radial center. The second bearing housing 122b protrudes toward the bearing housing storage recess 126. The second bearing housing 122b is rotatably supported on the axle 2 via the second bearing 113b.

[0032] An operation window 127 is formed in the bottom wall 122a radially outward of the second bearing housing 122b. The operation window 127 is used to operate the speed suppression device 1, which will be described later.

[0033] The bearing housing accommodating recess 126 is formed in a circular shape when viewed in the axial direction. The inner diameter of the bearing housing accommodating recess 126 is slightly larger than the inner diameter of the second accommodating recess 122. A cylindrical cover mounting portion 128 that protrudes outward in the vehicle width direction is integrally formed on the inner peripheral edge of the bearing housing accommodating recess 126. The inner diameter of the cover mounting portion 128 is the same as the inner diameter of the bearing housing accommodating recess 126. A cover (not shown) is attached to the cover mounting portion 128. The cover closes the opening of the cover mounting portion 128. This prevents water from splashing into the interior from the outside through the second bearing 113b or the operation window 127 and prevents dust from entering the interior.

[0034] The first disc portion 116 and the second disc portion 121 configured in this manner are coaxially overlapped and fastened together by bolts 123. A tire storage recess 124 is formed between the outer flange portions 116b, 121b of the outer peripheral surface 116a of the first disc portion 116 and the outer peripheral surface 12a of the second disc portion 121. The tire 112 is mounted so that a portion of the tire storage recess 124 is fitted into the tire storage recess 124. The first storage recess 117 and the second storage recess 122 are overlapped at their respective opening sides to form a closed periphery suppression device storage section 125. The speed suppression device 1 is stored in the suppression device storage section 125.

[0035] [First embodiment] <Speed ​​control device> In addition to the axle 2, the speed control device 1 includes a planetary gear mechanism 3 stored in the first storage recess 117, a bottomed cylindrical brake drum 11 attached to the second wheel plate 115 side of the planetary gear mechanism 3, and a centrifugal brake unit 13 stored within the brake drum 11.

[0036] The planetary gear mechanism 14 is configured in two stages. That is, the planetary gear mechanism 14 includes a first-stage gear mechanism 4 arranged on the bottom wall 117a of the first storage recess 117, and a second-stage gear mechanism 5 arranged outside the first-stage gear mechanism 4 in the vehicle width direction. The first-stage gear mechanism 4 includes a first sun gear 4a rotatably supported on the axle 2, and a plurality of (for example, three in this embodiment) first planetary gears 4b arranged around the first sun gear 4a.

[0037] Each first planetary gear 4b is meshed with the first sun gear 4a. The first planetary gears 4b are rotatably supported by first planetary support pins 118 that are integrally formed with the bottom wall 117a of the first storage recess 117. In other words, the bottom wall 117a functions as a planet carrier that integrally supports the multiple first planetary gears 4b.

[0038] The second-stage gear mechanism 5 is rotatably supported on the axle 2 and includes a second sun gear 5a arranged alongside the first sun gear 4a, a plurality of second planetary gears 5b (for example, three in this embodiment) arranged around the second sun gear 5a, and a second planet carrier 5c that integrally supports the second planetary gears 5b for free rotation. Each second planetary gear 5b is meshed with the second sun gear 5a. The second sun gear 5a also serves as part of the centrifugal brake unit 13.

[0039] The second planet carrier 5c includes a disk-shaped carrier plate 5d that protrudes radially outward from the outer peripheral surface of the first sun gear 4a, and second planet support pins 5e that protrude transversely outward from a transversely outer surface 5f of the carrier plate 5d. The second planet support pins 5e are disposed at positions corresponding to the second planet gears 5b and rotatably support the second planet gears 5b. Each of these gear mechanisms 4, 5 has a common internal gear 6 with which each of the planetary gears 4b, 5b meshes. The internal gear 6 is formed in a cylindrical shape that surrounds each of the planetary gears 4b, 5b. A brake drum 11 is fixed to the outer end of the internal gear 6 in the vehicle width direction. A lubricant (not shown) is applied to the meshing points of each of the gears 4a to 5b, 6.

[0040] The brake drum 11 is arranged with its opening 11a facing the internal gear 6. That is, the brake drum 11 includes a cylindrical portion 11b and a bottom portion 11c integrally formed on the outer side of the cylindrical portion 11b in the vehicle width direction. The inner peripheral surface of the cylindrical portion 11b is fitted into the outer peripheral surface of the internal gear 6. This fixes the brake drum 11 to the internal gear 6.

[0041] A through hole 11e is formed in the radial center of the bottom portion 11c. A bushing 12 provided on the axle 2 is press-fitted into the through hole 11e. This fixes the brake drum 11 to the axle 2. The internal gear 6 is fixed to the axle 2 via the brake drum 11. A plurality of operation windows 11f are formed in the bottom portion 11c. The outside of the wheel 103 and the inside of the brake drum 11 communicate with each other via the operation windows 11f and the operation window 127 of the second wheel plate 115.

[0042] FIG. 3 is a plan view of the brake mechanism 20 of the centrifugal brake unit 13 as seen from the outside in the vehicle width direction. As shown in FIGS. 2 and 3, the centrifugal brake unit 13 includes a boss plate 29, a portion of which is configured as the second sun gear 5a, and a brake mechanism 20 provided on the boss plate 29.

[0043] The boss plate 29 is formed by integrally molding a cylindrical boss portion 41 and a disk-shaped plate portion 42 that protrudes radially outward from the outer peripheral surface of the boss portion 41. The plate portion 42 is located slightly inward in the vehicle width direction from the axial center of the boss portion 41. Two support shafts 31 that support the brake shoes 23 protrude from an outer surface 42a on the outer side in the vehicle width direction of the plate portion 42. The two support shafts 31 are located radially opposite each other around the axle 2. The two support shafts 31 are each located on the outer peripheral portion of the plate portion 42. A second sun gear 5a is integrally molded with the outer peripheral surface 41a of the boss portion 41 that protrudes from an inner surface 42b on the inner side in the vehicle width direction of the plate portion 42. A lubricant (not shown) is applied between the boss portion 41 configured in this manner and the axle 2.

[0044] The brake mechanism 20 comprises two brake shoes 23, a shift cam 26, and two adjustment gears 27 rotatably supported on a boss plate 29, and two compression coil springs 24 and two support portions 25 respectively provided between each brake shoe 23 and the shift cam 26 in the radial direction.

[0045] The brake shoes 23 are rotatably supported by the two support shafts 31 of the plate portion 42. That is, the brake shoes 23 face the cylindrical portion 11b of the brake drum 11 in the radial direction. The two brake shoes 23 have the same configuration and are arranged point-symmetrically about the axle 2. For this reason, the following description will only focus on one of the two brake shoes 23. The other brake shoe 23 will be given the same reference numeral as the first brake shoe 23 and will not be described further.

[0046] The brake shoe 23 is formed in the shape of a plate that is long in the circumferential direction. A spring seat 22 is integrally formed with a first longitudinal end 23a of the brake shoe 23. The spring seat 22 protrudes in the circumferential direction from the radially outer end of the brake shoe 23. An avoidance recess 21 is formed in a second longitudinal end 23b of the brake shoe 23, which is opposite to the first longitudinal end 23a. The avoidance recess 21 is formed in a radially inner corner of the second end 23b of the brake shoe 23. The avoidance recess 21 prevents contact between the brake shoe 23 and the adjustment gear 27.

[0047] The radial outer surface 23c of the brake shoe 23 is formed in an arc shape so as to follow the outer periphery of the plate portion 42. A pad 30 is attached to the outer surface 23c on the side of the second end 23b. The brake shoe 23 is rotatably supported by a support shaft 31 at a position offset from the center in the longitudinal direction toward the first end 23a. When the brake shoe 23 swings around the support shaft 31, the pad 30 comes into contact with the cylindrical portion 11b of the brake drum 11.

[0048] Shift cam 26 is rotatably supported on an outer peripheral surface 41 a of a boss portion 41 that protrudes from an outer surface 42 a of a plate portion 42 . Two meshing portions 32 are formed on the outer periphery of shift cam 26, facing each other in the radial direction around axle 2. Each of the two meshing portions 32 has a plurality of teeth 32a. Each of the two meshing portions 32 faces each of brake shoes 23 in the radial direction near second ends 23b of brake shoes 23.

[0049] Cam portions 33 are formed on the outer periphery of shift cam 26. The cam portions 33 are opposed in the radial direction around axle 2, and are each disposed between two meshing portions 32 that are adjacent in the circumferential direction. The two cam portions 33 are opposed in the radial direction to spring seats 22 of brake shoes 23. Each of the two cam portions 33 has a plurality of (for example, four in the first embodiment) step portions 34a, 34b, 34c, 34d (first step portion 34a, second step portion 34b, third step portion 34c, fourth step portion 34d) that are at different radial distances from the axle 2.

[0050] The two first step portions 34a are arranged in front of the meshing portion 32 in the counterclockwise direction (see arrow CCW in FIG. 3, hereinafter simply referred to as counterclockwise CCW) when viewed from the outside in the vehicle width direction (see FIG. 3). The two second step portions 34b are disposed in front of the corresponding first step portions 34a in the counterclockwise direction. The two second step portions 34b are formed at positions farther away from the axle 2 than the first step portions 34a.

[0051] The two third step portions 34c are disposed in front of the corresponding second step portions 34b in the counterclockwise direction. The two third step portions 34c are formed at positions farther away from the axle 2 than the second step portions 34b. The two fourth step portions 34d are disposed in front of the corresponding third step portions 34c in the counterclockwise direction. The two fourth step portions 34d are formed at positions farther away from the axle 2 than the third step portions 34c.

[0052] One adjusting gear 27 is provided on each plate portion 42 between second end portion 23b of brake shoe 23 and meshing portion 32 of shift cam 26 when viewed in the axial direction. The two adjusting gears 27 have the same configuration. Therefore, the following description will only describe one of the two adjusting gears 27. The other adjusting gear 27 will be given the same reference numeral as the first adjusting gear 27, and description thereof will be omitted.

[0053] The adjustment gear 27 is a so-called spur gear. The adjustment gear 27 is rotatably supported by the plate portion 42. A plurality of teeth 27a that mesh with the meshing portion 32 of the shift cam 26 are formed on the outer periphery of the adjustment gear 27. The adjustment gear 27 is formed with an engagement recess 27b into which the end of a tool (not shown), such as a hexagonal wrench, is inserted. The engagement recess 27b is exposed to the outside of the wheel 103 through the operation window 11f of the brake drum 11 and the operation window 127 of the second wheel plate 115.

[0054] With this configuration, a tool (not shown) is inserted into the engagement recess 27b from outside the wheel 103 through the operation window 127 of the second wheel plate 115 and the operation window 11f of the brake drum 11. By rotating this tool, the adjustment gear 27 can be rotated relative to the plate portion 42.

[0055] The compression coil spring 24 is disposed radially between the spring seat 22 of the brake shoe 23 and the cam portion 33 of the shift cam 26. The radially outer end of the compression coil spring 24 abuts against the spring seat 22.

[0056] <Support part> FIG. 4 is a plan view of the support portion 25. As shown in FIG. 4, the support portion 25 faces the spring seat 22 of the brake shoe 23 in the radial direction. The support portion 25 is integrally formed with a spring seat 25a against which the radially inner end of the compression coil spring 24 abuts, and two support protrusions 25b and 25c that protrude from the spring seat 25a toward the cam portion 33. The two support protrusions 25b and 25c have spherical or arc-shaped surfaces.

[0057] Each support portion 25 is disposed between the compression coil spring 24 and the cam portion 33 of the shift cam 26. The two support portions 25 have the same configuration. Therefore, the following description will only describe one of the two support portions 25. The other support portion 25 will be given the same reference numeral as the first support portion 25, and a description thereof will be omitted.

[0058] The support portion 25 is integrally formed with a spring seat 25a against which the radially inner end of the compression coil spring 24 abuts, and two support protrusions 25b and 25c protruding from the spring seat 25a toward the cam portion 33. A limiting protrusion 25d that protrudes toward spring seat 22 of brake shoe 23 is integrally formed on support surface 25e of spring seat 25a that faces spring seat 22 of brake shoe 23. Limiting protrusion 25d is formed, for example, in a cylindrical shape. Limiting protrusion 25d is inserted into compression coil spring 24. The protruding length Lo of limiting protrusion 25d is a length that does not abut against spring seat 22 of brake shoe 23 when support portion 225 is positioned between first step 34a to third step 34c of four steps 34a to 34d of shift cam 26 and when wheel 103 is not rotating.

[0059] The two support protrusions 25b, 25c have spherical or arc-shaped surfaces. The corners between the steps 34a to 34d of the cam portion 33 fit between the two support protrusions 25b, 25c. This makes it possible to position the support portion 25 for each of the steps 34a to 34d of the cam portion 33. The support portion 25 positions the compression coil spring 24 in a slightly compressed state between the support portion 25 and the spring seat 22 of the brake shoe 23. Therefore, the spring seat 22 of the brake shoe 23 is elastically biased radially outward by the compression coil spring 24. The support portion 25 is constantly elastically biased against the cam portion 33 by the compression coil spring 24.

[0060] <Function of speed control device> <Function of the centrifugal brake unit> Next, the operation of the speed control device 1 will be described. First, the operation of the centrifugal brake unit 13 will be described. When the user pushes the operating unit 104 of the walker 101, the wheels 103 rotate and the walker 101 moves forward. As the wheels 103 rotate, the multiple first planetary gears 4b rotatably supported on the bottom wall 117a of the first storage recess 117 revolve around the first sun gear 4a while meshing with the first sun gear 4a and the internal gear 6. This causes the first sun gear 4a and the carrier plate 5d integrated with the first sun gear 4a to rotate.

[0061] When the carrier plate 5d rotates, the multiple second planetary gears 5b rotatably supported on the carrier plate 5d revolve around the second sun gear 5a while meshing with the second sun gear 5a and the internal gear 6. This causes the second sun gear 5a and the boss plate 29 integrated with the second sun gear 5a to rotate. In this way, the rotation of the wheel 103 is accelerated by the planetary gear mechanism 3 and transmitted to the boss plate 29.

[0062] As the boss plate 29 rotates, centrifugal force acts on the brake shoe 23, which is rotatably supported on the boss plate 29. At this time, the brake shoe 23 is rotatably supported on the support shaft 31 at a position offset from the center in the longitudinal direction toward the first end 23a. Therefore, when centrifugal force acts on the brake shoe 23, the brake shoe 23 attempts to swing around the support shaft 31 so that the second end 23b side of the brake shoe 23 moves radially outward. As a result of this swing, the first end 23a side of the brake shoe 23 attempts to displace radially inward, that is, in the direction that compresses the compression coil spring 24.

[0063] When the walking frame 101 is traveling slowly and the number of rotations of the boss plate 29 is smaller than a predetermined number of rotations. In other words, when the number of rotations of the wheel 103 is smaller than a predetermined number of rotations, the centrifugal force acting on the brake shoe 23 is also small. Therefore, the spring force of the compression coil spring 24 is greater than the compressive force of the compression coil spring 24 due to the brake shoe 23. Therefore, the amount of oscillation of the brake shoe 23 is small, and the pad 30 of the brake shoe 23 does not come into contact with the cylindrical portion 11b of the brake drum 11.

[0064] When the traveling speed of the walker 101 becomes faster than a predetermined value and the rotation speed of the boss plate 29 exceeds a predetermined rotation speed. In other words, when the rotation speed of the wheel 103 exceeds a predetermined rotation speed, the centrifugal force acting on the brake shoe 23 increases. This causes the brake shoe 23 to swing significantly against the spring force of the compression coil spring 24, and the pad 30 of the brake shoe 23 is pressed against the cylindrical portion 11b of the brake drum 11. This applies a braking force to the brake drum 11, suppressing the rotation of the wheel 103 and reducing the traveling speed of the walker 101.

[0065] <Shift cam action> Next, the operation of the shift cam 26 will be described. A cover (not shown) of wheel 103 is removed, and adjustment gear 27 is rotated from the outside of wheel 103 using a tool (not shown). This rotates shift cam 26 meshed with adjustment gear 27, and the position of support portion 25 relative to steps 34a to 34d of cam portion 33 is changed.

[0066] More specifically, assume that the support portion 25 is positioned at the first step portion 34a. Hereinafter, this state will be referred to as first-stage braking. In first-stage braking, the compression coil spring 24 is compressed to a small extent. Therefore, the spring force of the compression coil spring 24, i.e., the force with which the compression coil spring 24 elastically biases the spring seat 22, is minimized. As a result, the brake shoe 23 oscillates with a relatively small centrifugal force. Therefore, braking force is applied to the brake drum 11 even when the rotation speed of the wheel 103 is low.

[0067] Next, shift cam 26 is rotated clockwise in FIG. 3 (see arrow CW in FIG. 3, hereinafter simply referred to as clockwise CW) from first step portion 34a via adjustment gear 27. This causes support portion 25 to ride up onto second step portion 34b. Support portion 25 is positioned on second step portion 34b. Hereinafter, this state will be referred to as second-stage braking. In the second stage braking, the support portion 25 is closer to the spring seat 22 than in the first stage braking. This increases the amount of compression of the compression coil spring 24, and increases the spring force of the compression coil spring 24. As a result, the brake shoe 23 applies a braking force to the brake drum 11 from the point in time when the rotation speed of the wheel 103 becomes higher than in the first stage braking.

[0068] Next, when shift cam 26 is further rotated clockwise (CW) via adjustment gear 27, support portion 25 rides up onto third step portion 34c. Support portion 25 is positioned on third step portion 34c. Hereinafter, this state will be referred to as third-stage braking. In the third stage braking, the support portion 25 is closer to the spring seat 22 than in the second stage braking. This increases the amount of compression of the compression coil spring 24, further increasing the spring force of the compression coil spring 24. As a result, the brake shoe 23 applies a braking force to the brake drum 11 from the point when the rotation speed of the wheel 103 becomes even higher than in the second stage braking.

[0069] Next, when shift cam 26 is further rotated clockwise (CW) via adjustment gear 27, support portion 25 rides up onto fourth step portion 34d. Support portion 25 is positioned on fourth step portion 34cd. Hereinafter, this state will be referred to as the fourth-stage brake. In the fourth stage brake, the support portion 25 is closer to the spring seat 22 than in the third stage brake. This increases the compression amount of the compression coil spring 24, further increasing the spring force of the compression coil spring 24. As a result, the brake shoe 23 applies a braking force to the brake drum 11 from the point when the rotation speed of the wheel 103 becomes even higher than in the third stage brake.

[0070] In this way, shift cam 26 has the role of adjusting the spring force of compression coil spring 24 by changing the position of support portion 25 depending on its position in the rotational direction. As a result, it is possible to adjust the timing at which braking force acts on brake drum 11. In other words, shift cam 26 has the role of displacing support portion 25 in the compression direction of compression coil spring 24, thereby reducing the pressing force of brake shoe 23 against cylindrical portion 11b of brake drum 11. Shift cam 26 has the role of displacing support portion 25 in the expansion direction of compression coil spring 24, thereby increasing the pressing force of brake shoe 23 against cylindrical portion 11b of brake drum 11.

[0071] <Function of the support part> 5 is a plan view of brake mechanism 20 as seen from the outside in the vehicle width direction, and shows a state in which support portion 25 is positioned on fourth step portion 34d of shift cam 26. FIG. 5 corresponds to FIG. 3 described above. As shown in Figure 5, the protruding length Lo of the limiting protrusion 25d is the length that will abut against the spring seat 22 of the brake shoe 23 regardless of the rotation of the wheel 103 when it is positioned on the fourth step 34d of the four step portions 34a to 34d of the shift cam 26. Hereinafter, the state in which support portion 25 is positioned between first step portion 34a to third step portion 34c of shift cam 26 will be referred to as the brake mechanism operating state. The state in which support portion 25 is positioned at fourth step portion 34d of shift cam 26 will be referred to as the brake mechanism non-operating state.

[0072] With this configuration, as shown in Figure 3, when the brake mechanism is in operation and the wheel 103 is not rotating, the limiting protrusion 25d does not abut against the spring seat 22 of the brake shoe 23. Therefore, when the running speed of the walker 101 increases above a predetermined speed and the number of rotations of the wheel 103 exceeds a predetermined number of rotations, the centrifugal force acting on the brake shoe 23 presses the pad 30 of the brake shoe 23 against the cylindrical portion 11b of the brake drum 11. This causes a braking force to act on the brake drum 11.

[0073] In contrast, as shown in Figure 5, when the brake mechanism is in an inoperative state, the limiting protrusion 25d abuts against the spring seat 22 of the brake shoe 23 regardless of the rotation of the wheel 103. This prevents the brake shoe 23 from swinging. In this state, the brake shoe 23 does not swing even when centrifugal force acts on the brake shoe 23. As a result, no braking force acts on the brake drum 11, and the brake mechanism 20 is not activated.

[0074] Here, the difference in role between the compression coil spring 24 and the limiting protrusion 25d will be described in detail. The compression coil spring 24 controls the pressing force of the brake shoe 23 against the brake drum 11 and the timing at which the brake shoe 23 starts to swing, depending on the position of the support portion 25. In other words, the compression coil spring 24 controls the amount of swing of the brake shoe 23. In contrast, the limiting protrusion 25d limits the swing (displacement) itself of the brake shoe 23. Limiting the swing of the brake shoe 23 means preventing the brake shoe 23 from swinging beyond a predetermined range. In other words, limiting the swing of the brake shoe 23 means restricting the pad 30 of the brake shoe 23 so that it does not come into contact with the brake drum 11, regardless of the rotation of the wheel 103 (determining the swing range).

[0075] As described above, the speed control device 1 in the first embodiment includes the brake drum 11 that is integral with the wheel 103, the brake shoe 23 that contacts the brake drum 11 to apply a braking force to the brake drum 11, and the limiting protrusion 25d that limits the swing of the brake shoe 23. Therefore, the limiting protrusion 25d can deactivate the speed control device 1 regardless of the rotation of the wheel 103. In other words, the brake mechanism 20 can be placed in a brake mechanism deactivation state.

[0076] The brake mechanism 20 includes a compression coil spring 24 that controls the amount of oscillation of the brake shoe 23, a support portion 25 that supports the compression coil spring 24, and a shift cam 26 that positions the support portion 25 in stages. With this configuration, the support portion 25 is provided with a limiting protrusion 25d. Therefore, when the brake shoe 23 oscillates against the spring force of the compression coil spring 24 and attempts to contact the cylindrical portion 11b of the brake drum 11, the limiting protrusion 25d can prevent this contact. Therefore, the brake mechanism can be reliably placed in an inoperative state with a simple structure. By simply forming the limiting protrusion 25d integrally with the support portion 25, the brake mechanism can be easily brought into a non-operating state.

[0077] The brake shoe 23 is provided so as to be able to swing freely around a support shaft 31. A spring seat 22 is integrally formed at a first end 23a of the brake shoe 23. A pad 30 is attached to a second end 23b of the brake shoe 23. With this configuration, the pad 30 can be moved closer to the cylindrical portion 11b in accordance with the rotational speed of the wheel 103. The brake shoe 23 can be oscillated against the spring force of the compression coil spring 24. Therefore, the operation timing of the speed suppression device 1 can be changed for each rotational speed of the wheel 103 with a simple structure.

[0078] The walker 101 equipped with the speed control device 1 as described above can deactivate the speed control device 1.

[0079] In the first embodiment described above, the support portion 25 is provided with the limiting protrusion 25d as a limiting portion that limits the swing of the brake shoe 23. However, the present invention is not limited to this, and any configuration that can limit the swing of the brake shoe 23 may be used. This will be described in detail below.

[0080] [First Modification of the First Embodiment] 6 is a plan view of brake mechanism 20 of a first modified example of the first embodiment, viewed from the outside in the vehicle width direction, and shows a state in which support portion 25 is positioned on fourth step portion 34d of shift cam 26. FIG. 6 corresponds to FIG. 3 described above. 5, a limiting protrusion 25d may be provided on the spring seat 22 of the brake shoe 23 instead of the support portion 25. The limiting protrusion 25d protrudes from the contact surface 22a of the spring seat 22 that faces the support portion 25 toward the support portion 25. Therefore, according to the first modified example described above, it is possible to achieve the same effects as those of the first embodiment described above.

[0081] [Second Modification of the First Embodiment] 7 is a plan view of brake mechanism 20 of a second modified example of the first embodiment, viewed from the outside in the vehicle width direction, and shows a state in which support portion 25 is positioned on fourth step portion 34d of shift cam 26. FIG. 7 corresponds to FIG. 3 described above.

[0082] As shown in Fig. 7, instead of providing the limiting protrusion 25d on the support portion 25, a second compression coil spring 50 may be provided. The second compression coil spring 50 is housed radially inside the compression coil spring 24. The second compression coil spring 50 may limit the oscillation of the brake shoe 23. In this case, the oscillation of the brake shoe 23 may be limited by the combined spring force of the compression coil spring 24 and the spring force of the second compression coil spring 50. Therefore, according to the second modified example, it is possible to achieve the same effects as those of the first embodiment.

[0083] [Third Modification of the First Embodiment] 8 is a plan view of brake mechanism 20 of a third modified example of the first embodiment, viewed from the outside in the vehicle width direction, and shows a state in which support portion 25 is positioned on fourth step portion 34d of shift cam 26. FIG. 8 corresponds to FIG. 5 described above. 8, instead of providing limiting protrusion 25d on support portion 25, limiting protrusion 51 may be provided on shift cam 26. When support portion 25 is positioned on fourth step portion 34d of shift cam 26, limiting protrusion 51 abuts against spring seat 22 of brake shoe 23. Therefore, according to the third modified example described above, it is possible to achieve the same effects as those of the first embodiment described above.

[0084] [Fourth Modification of the First Embodiment] Fig. 9 is a plan view of the brake mechanism 20 of the fourth modified example of the first embodiment as seen from the outside in the vehicle width direction, showing the brake mechanism in an operating state (single-stage braking). Fig. 10 is a plan view of the brake mechanism 20 of the fourth modified example of the first embodiment as seen from the outside in the vehicle width direction, showing the brake mechanism in an inoperable state (four-stage braking). Figs. 9 and 10 correspond to Fig. 5 described above.

[0085] As shown in FIG. 9, instead of providing the limiting protrusion 25d on the support portion 25, a limiting locking portion 52 may be provided on the adjustment gear 27 and the brake shoe 23. The limiting locking portion 52 includes a gear-side locking pawl 53 integrally molded with the adjusting gear 27 and a brake-side locking pawl 54 integrally molded with the brake shoe 23. The gear-side locking pawl 53 is integrally molded with a part of the tooth portion 27a of the adjusting gear 27. The brake-side locking pawl 54 is integrally molded on the radially inner side of the avoidance recess 21 of the brake shoe 23. These locking pawls 53, 54 are not locked to each other when the brake mechanism is in an operating state.

[0086] 10, when the adjustment gear 27 is rotated to the brake mechanism inoperative state, the locking claws 53, 54 are locked together, thereby preventing the brake shoe 23 from swinging. Therefore, the fourth modified example described above can achieve the same effects as the first embodiment described above.

[0087] In the fourth modified example described above, the limiting locking portion 52 (gear-side locking claw 53, brake-side locking claw 54) is provided on each of the adjusting gear 27 and the brake shoe 23. However, this is not limited to this, and it is sufficient if the limiting locking portion 52 is provided on at least one of the adjusting gear 27 and the brake shoe 23. When the limiting locking portion 52 is provided on either one of the adjusting gear 27 or the brake shoe 23, it is sufficient if the limiting locking portion 52 abuts against or locks on the other of the adjusting gear 27 or the brake shoe 23, thereby preventing the brake shoe 23 from swinging.

[0088] [Second embodiment] Next, a second embodiment will be described with reference to Figures 1 and 2 and based on Figures 11 and 12. The same reference numerals are used to designate the same aspects as in the first embodiment, and the description thereof will be omitted. In the second embodiment, the walking frame 101 is similar to the first embodiment in that it includes a body 102, a plurality of wheels 103 provided on the bottom of the body 102, and an operating unit 104 provided on the top of the body 102. The wheels 103 are similar to the first embodiment in that they include a speed control device 201. The speed control device 201 is similar to the first embodiment in that it includes an axle 2, a planetary gear mechanism 3, a brake drum 11 attached to the planetary gear mechanism 3, and a centrifugal brake unit 213 housed in the brake drum 11. These basic configurations are also the same in the following embodiments.

[0089] Fig. 11 is a perspective view of the boss plate 229 in the second embodiment. Fig. 12 is an axial cross-sectional view of the boss portion 241, showing an enlarged portion. As shown in FIGS. 11 and 12, the second embodiment differs from the first embodiment in that the shape of a boss portion 241 in the second embodiment is different from the shape of a boss portion 41 in the first embodiment. More specifically, two first recesses 43a and one second recess 43b are formed on the inner peripheral surface 241b of the boss portion 241. Each of the recesses 43a, 43b is formed in an annular shape around the entire circumference of the inner peripheral surface 241b. The two first recesses 43a are arranged on both sides of the boss portion 41 in the axial direction. The second recess 43b is arranged between the two first recesses 43a.

[0090] A lubricant (not shown) is filled in the recesses 43a and 43b between the boss portion 241 configured in this manner and the axle 2. The lubricant remains in the recesses 43a and 43b. This allows the boss plate 229 to rotate smoothly relative to the axle 2.

[0091] <Function of boss plate> Next, the function of the boss plate 229 will be described. First, the situation when the speed control device 201 is in use will be described. When the pad 30 of the brake shoe 23 is pressed against the cylindrical portion 11b of the brake drum 11, wear powder may be generated. Furthermore, wear powder may be generated when the gears 4a to 5b of the planetary gear mechanism 3 mesh with each other. Foreign matter such as wear powder may enter between the axle 2 and the boss portion 41 of the boss plate 229. In such a case, the foreign matter may create resistance and prevent the boss plate 229 from rotating smoothly relative to the axle 2, which may result in a decrease in performance of the speed control device 201 or the generation of abnormal noise when the speed control device 201 is in use.

[0092] Here, two first recesses 43a and one second recess 43b are formed on the inner circumferential surface 241b of the boss portion 241. The two first recesses 43a are arranged on both axial sides of the boss portion 241. Therefore, foreign matter that enters between the axle 2 and the boss portion 241 of the boss plate 29 enters the first recess 43a and remains there. This prevents foreign matter from passing through the first recess 43a and entering deep into the boss portion 241.

[0093] If foreign matter gets into the first recess 43a, the lubricant (not shown) that has been retained in the first recess 43a may be pushed out of the first recess 43a. However, the lubricant (not shown) remains in the second recess 43b located between the two first recesses 43a. This allows the lubricant (not shown) to be reliably retained between the boss portion 41 and the axle 2. If a foreign object passes through the first recess 43a and penetrates deep into the boss portion 241, the foreign object will also enter the second recess 43b and stay there. This prevents the foreign object from spreading throughout the entire space between the boss portion 241 and the axle 2.

[0094] As described above, the speed control device 201 in the second embodiment has the first recess 43a and the second recess 43b formed on the inner circumferential surface 241b of the boss portion 241. These recesses 43a and 43b make it possible to stop foreign matter that enters between the axle 2 and the boss portion 241. This makes it possible to prevent foreign matter from spreading throughout the entire space between the axle 2 and the boss portion 241. Therefore, in addition to the same effects as those of the first embodiment, it is possible to suppress performance degradation of the speed control device 201 and to suppress abnormal noise when the speed control device 201 is in use.

[0095] Moreover, each of the recesses 43a, 43b is formed in an annular shape around the entire circumference of the inner circumferential surface 241b. This prevents foreign matter from penetrating deep into the boss portion 241 along each of the recesses 43a, 43b. This also prevents lubricant (not shown) from leaking out of the boss portion 241 from the recesses 43a, 43b. This ensures that the lubricant (not shown) is kept between the axle 2 and the boss portion 241. This ensures that performance degradation of the speed control device 1 is prevented, and that abnormal noise during use of the speed control device 1 is also prevented.

[0096] The two first recesses 43a are arranged on both axial sides of the boss portion 241. This makes it possible to actively prevent foreign matter from entering on both axial sides of the boss portion 241. This makes it possible to prevent foreign matter from entering deep into the boss portion 241. In addition to the two first recesses 43a, a second recess 43b is disposed between these first recesses 43a. The first recess 43a actively stops foreign matter, while the second recess 43b can stop a lubricant (not shown) by contacting it. In this way, each recess 43a, 43b can have a different function, which more reliably prevents performance degradation of the speed control device 201 and more reliably prevents abnormal noise during use of the speed control device 201.

[0097] Incidentally, centrifugal force acts on foreign matter that has entered between the axle 2 and the boss portion 41 due to the rotation of the boss portion 241. Since each of the recesses 43a, 43b is formed on the inner peripheral surface 241b of the boss portion 241, it is located on the outer peripheral side (outside in the radial direction) of the gap between the axle 2 and the boss portion 241. Therefore, foreign matter that is subjected to centrifugal force can be reliably retained in each of the recesses 43a, 43b. Lubricant (not shown) between the axle 2 and the boss portion 241 can also be reliably retained in each of the recesses 43a, 43b.

[0098] A walker 101 equipped with the speed control device 201 as described above can suppress a decrease in performance of the walker 101 and can also suppress abnormal noises when the walker 101 is in use.

[0099] In the second embodiment described above, two first recesses 43a and one second recess 43b are formed on the inner circumferential surface 241b of the boss portion 241. The recesses 43a, 43b are formed in an annular shape around the entire circumference of the inner circumferential surface 241b. However, this is not a limitation, and the number and shape of the recesses are not limited to this. Various shapes can be adopted for the shape of the recesses.

[0100] Preferably, the recesses 43a and 43b extend circumferentially around the entire circumference. For example, instead of each recess 43a and 43b, a spiral recess may be formed along the inner peripheral surface 241b. At least one recess may be formed. Even with one recess, it is possible to retain foreign matter that enters between the axle 2 and the boss portion 241 in the recess. Each recess 43a and 43b may be formed on the supported outer peripheral surface 2b, which is supported by the boss portion 241, of the outer peripheral surface 2a of the axle 2. Even when formed in this way, it is possible to retain foreign matter that enters between the axle 2 and the boss portion 41 in the recess.

[0101] [Third embodiment] Next, a third embodiment will be described with reference to FIGS. Fig. 13 is a plan view of a carrier plate 5d according to the third embodiment as seen from the outside in the vehicle width direction, and Fig. 14 is a cross-sectional view taken along line AA in Fig. 13 . As shown in Figures 13 and 14, the difference between the speed control device 301 of the third embodiment and the speed control device 1 of the first embodiment is that in the third embodiment, a damper 60 is provided on the carrier plate 5d, whereas in the first embodiment, a damper 60 is not provided.

[0102] The damper 60 is disposed on the outer surface 5f of the carrier plate 5d between adjacent second planetary gears 5b in the circumferential direction. The damper 60 is formed, for example, from rubber. The damper 60 is formed in a fan shape when viewed in the vehicle width direction so that its circumferential width increases toward the radially outer side, in order to avoid contact with the second planetary gears 5b and the second sun gear 5a.

[0103] The outer periphery of the damper 60 protrudes radially outward beyond the outer periphery of the carrier plate 5d when viewed in the vehicle width direction. An annular protrusion 61 that protrudes inward in the vehicle width direction is integrally formed with this protruding outer periphery of the damper 60. The annular protrusion 61 covers a portion of the outer periphery 5g of the carrier plate 5d.

[0104] A pin insertion hole 62 is formed in the radial center of the damper 60. The pin insertion hole 62 has a hole main body 62a and a counterbore portion 62b formed on the outer side of the hole main body 62a in the vehicle width direction. The counterbore portion 62b is arranged coaxially with the hole main body 62a and communicates with the hole main body 62a. A fixing pin 63 is inserted into the pin insertion hole 62 from the outer side in the vehicle width direction. The fixing pin 63 is fixed to the carrier plate 5d. This fixes the damper 60 to the carrier plate 5d. When the fixing pin 63 is inserted into the pin insertion hole 62, the head portion 63a is housed in the counterbore portion 62b. This prevents the fixing pin 63 from protruding from the damper 60.

[0105] Therefore, according to the third embodiment described above, in addition to achieving the same effects as the first embodiment described above, the damper 60 can suppress vibrations occurring in the carrier plate 5d, and can also suppress noise.

[0106] In the above-described third embodiment, the damper 60 is provided on the outer surface 5f of the carrier plate 5d. That is, the damper 60 is provided in the second-stage gear mechanism 5 of the planetary gear mechanism 3. However, this is not limiting, and the damper 60 may be provided in the first-stage gear mechanism 4. That is, the damper 60 may be provided on the bottom wall 117a of the first storage recess 117.

[0107] In the third embodiment described above, the damper 60 is fixed to the carrier plate 5d using the fixing pin 63. However, this is not limited to this, and it is sufficient if the damper 60 can be fixed to the carrier plate 5d. For example, instead of the fixing pin 63, the damper 60 may be fixed to the carrier plate 5d using adhesive or bolts.

[0108] In the third embodiment described above, the rubber damper 60 is provided to suppress vibrations and noise generated in the carrier plate 5d. However, this is not limiting, and the damper 60 may be any damper that can suppress vibrations and noise generated in the carrier plate 5d. For example, the damper 60 may be made of resin instead of rubber.

[0109] [Fourth embodiment] Next, a fourth embodiment will be described with reference to FIGS. 15 is a plan view of the brake mechanism 420 of the centrifugal brake unit 413 in the fourth embodiment when the first stage brake is applied, as viewed from the outside in the vehicle width direction. FIG. 15 corresponds to FIG. 15, the difference between speed control device 401 of the fourth embodiment and speed control device 1 of the first embodiment is that the shape of shift cam 426 of the fourth embodiment is different from the shape of shift cam 26 of the first embodiment. More specifically, the number of tooth portions 432a of meshing portion 432 in the fourth embodiment is different from the number of tooth portions 32a of meshing portion 32 in the first embodiment.

[0110] That is, in the meshing portion 432 of the fourth embodiment, tooth portions 432a are not formed in locations corresponding to both circumferential sides of the plurality of tooth portions 32a (see FIG. 3) in the first embodiment. Of the both circumferential sides of the meshing portion 432 where tooth portions 432a are not formed, a recessed portion 66 is formed on the front side in the clockwise (CW) direction. The recessed portion 66 is formed so as to follow the tooth addendum circle of the adjustment gear 27 when the shift cam 426 is rotated in the first brake position. That is, when the shift cam 426 is rotated in the first brake position, the toothed portions 432a of the meshing portion 432 and the toothed portions 27a of the adjustment gear 27 do not mesh. The adjustment gear 27 rotates idly on the recessed portion 66.

[0111] 16 is a plan view of the brake mechanism 420 of the centrifugal brake unit 413 in the fourth embodiment when the fourth stage brake is applied, as viewed from the outside in the vehicle width direction. FIG. 16 corresponds to FIG. As shown in Figure 16, the rotational position of shift cam 426 during fourth-stage braking is similar to the rotational position of shift cam 426 during first-stage braking. That is, even during the rotational position of shift cam 426 during fourth-stage braking, tooth portion 432a of meshing portion 432 does not mesh with tooth portion 27a of adjustment gear 27. Adjustment gear 27 rotates idly on the circumferential side surface of tooth portion 432a. Hereinafter, this rotation will be simply referred to as "rotating idly on the side surface of tooth portion 432a."

[0112] <Shift cam action> Next, the operation of shift cam 426 will be described. 15 and 16, in brake mechanism 420, when adjustment gear 27 is rotated counterclockwise (CCW), shift cam 426 is rotated clockwise (CW), and the brake stage increases from stage 1 to stage 4. Conversely, when adjustment gear 27 is rotated clockwise (CW), brake mechanism 420 rotates shift cam 426 counterclockwise (CCW), and the brake stage decreases from stage 4 to stage 1.

[0113] Now, suppose that, as shown in FIG. 15 , when shift cam 426 is in the first-stage brake rotation position, the user accidentally rotates adjusting gear 27 further clockwise (CW). In such a case, adjusting gear 27 rotates freely on recess 66. This prevents shift cam 426 from rotating counterclockwise (CCW) more than necessary. This prevents, for example, contact between shift cam 426 and support portion 25.

[0114] Meanwhile, as shown in FIG. 16, suppose that when shift cam 426 is in the rotation position for the fourth brake stage, the user accidentally rotates adjustment gear 27 further counterclockwise (CCW). In such a case, adjustment gear 27 rotates freely on the side surface of tooth portion 432a. This prevents shift cam 426 from rotating clockwise (CW) more than necessary. This prevents, for example, support portion 25 from riding over fourth step portion 34d and coming into contact with tooth portion 432a.

[0115] 17 is an explanatory diagram showing the behavior of shift cam 426 when adjustment gear 27 rotates idly on the side surface of tooth portion 432a. FIG. 17 corresponds to FIG. 17, when adjustment gear 27 rotates idly on the side surface of tooth portion 432a, tooth portions 27a of adjustment gear 27 pass over the side surface of tooth portion 432a one after another. At this time, tooth portion 432a of shift cam 426 is slightly pushed by tooth portions 27a of adjustment gear 27 (see portion A in FIG. 17), causing shift cam 426 to rotate slightly clockwise (CW).

[0116] Support portion 25 is elastically pressed against cam portion 33 of shift cam 426 by compression coil spring 24. Therefore, when shift cam 426 rotates slightly clockwise (CW), compression coil spring 24 pushes back shift cam 426, restoring it to its original position. By repeating this operation, ratcheting action is performed. That is, brake mechanism 420 of the fourth embodiment is equipped with a ratchet mechanism 67.

[0117] Therefore, according to the fourth embodiment described above, it is possible to prevent the brake mechanism 420 from being damaged due to, for example, an erroneous operation by the user.

[0118] In the first and fourth embodiments described above, the support portion 25 provided between the compression coil spring 24 and the shift cam 26, 426 is described as being formed integrally with the spring seat 25a and the two support protrusions 25b, 25c protruding from the spring seat 25a. However, this is not limited thereto, and the support portion 25 may have any shape as long as it can be positioned at the respective positions of the first to fourth stage brakes. For example, a sphere may also be used as the support portion 25.

[0119] In the above-described first to fourth embodiments, the shift cam 26 that rotates around the axle 2 has been described as the shift unit that displaces the support portion 25 in the compression direction of the compression coil spring 24. However, the present invention is not limited to this, and the shift unit may be configured in any way as long as it can displace the support portion 25 in the compression direction of the compression coil spring 24. For example, the shift unit may have a structure that directly displaces the support portion 25. Other configurations, such as those described below, may also be used.

[0120] [Fifth embodiment] Next, a fifth embodiment will be described with reference to FIG. FIG. 18 is a plan view of a brake mechanism 520 of a centrifugal brake unit 513 in the fifth embodiment, as viewed from the outside in the vehicle width direction. 18, the difference between the speed control device 501 of the fifth embodiment and the speed control device 1 of the first embodiment is that the fifth embodiment provides a shift unit 71 instead of the shift cam 26 of the first embodiment, and an adjustment piece 72 instead of the adjustment gear 27 of the first embodiment. Accordingly, the shape of the two support portions 525 of the fifth embodiment is different from the shape of the two support portions 25 of the first embodiment.

[0121] The shift unit 71 includes a slide block 91, a compression coil spring 92 having a first end 92a connected to the slide block 91, and a spring seat 93 connected to a second end 92b of the compression coil spring 92 opposite the first end 92a. When viewed in the vehicle width direction, the slide block 91 is formed symmetrically about a line Li that passes through the axis of the axle 2 (not shown in FIG. 18) and is perpendicular to the opposing direction of the two support parts 525. That is, the slide block 91 includes a rod-shaped shift lever 96 that extends in the opposing direction of the two support parts 525, and a shift-side spring seat 94 and a contact pin 95 that are integrally molded at the center of the shift lever 96 in the longitudinal direction. The shift-side spring seat 94 and the contact pin 95 are arranged on both sides of the shift lever 96.

[0122] A first end 92a of the compression coil spring 92 is connected to a shift-side spring seat 94. The axis of the compression coil spring 92 coincides with the line Li. A spring seat 93 connected to a second end 92b of the compression coil spring 92 is fixed to the plate portion 42 of the boss plate 29. The compression coil spring 92 is disposed between the spring seat 93 and a shift-side spring seat 94 in a slightly compressed state.

[0123] The adjustment piece 72 is disposed opposite the tip of the contact pin 95 of the slide block 91 on the straight line Li. The adjustment piece 72 is formed in the shape of an equilateral triangle when viewed in the vehicle width direction. A rounded chamfered portion 73 is formed at each of the three vertices of the adjustment piece 72. The rounded chamfered portion 73 is formed in the shape of an arc when viewed in the vehicle width direction.

[0124] The adjustment top 72 is rotatably supported by the plate portion 42. The rotation axis C of the adjustment top 72 is eccentric with respect to the center of the adjustment top 72. Therefore, the distances La, Lb, and Lc (first distance La, second distance Lb, and third distance Lc) between the rotation axis C and the three sides 72a, 72b, and 72c (first side 72a, second side 72b, and third side 72c) of the adjustment top 72 are all different. Specifically, the second distance Lb between the second side 72b and the rotation axis C is longer than the first distance La between the first side 72a and the rotation axis C. The third distance Lc between the third side 72c and the rotation axis C is longer than the second distance Lb. In addition, an engagement recess 74 is formed on the adjustment piece 72 coaxially with the rotation axis C and on the outer side in the vehicle width direction. The end of a tool (not shown), such as a hex wrench, is inserted into the engagement recess 74.

[0125] In this configuration, the contact pin 95 of the slide block 91 abuts against one of the three sides 72a, 72b, and 72c of the adjustment piece 72. The slide block 91 is elastically biased toward the adjustment top 72 by a compression coil spring 92. Therefore, the contact pin 95 always abuts against the sides 72a, 72b, and 72c of the adjustment top 72. When the adjustment top 72 is rotated in this state, the slide block 91 slides along the straight line Li according to the distances La, Lb, and Lc.

[0126] Hereinafter, the rotational position of the adjustment piece 72 where the contact pin 95 abuts against the first side 72a will be referred to as the first rotational position, the rotational position of the adjustment piece 72 where the contact pin 95 abuts against the second side 72b will be referred to as the second rotational position, and the rotational position of the adjustment piece 72 where the contact pin 95 abuts against the third side 72c will be referred to as the third rotational position.

[0127] The two support portions 525 are formed symmetrically with respect to the line Li. Therefore, in the following explanation, one of the two support portions 525 will be explained. The other support portion 525 will be given the same reference numeral as the one support portion 525, and explanation thereof will basically be omitted. Explanation of the other support portion 525 will be made as necessary.

[0128] Each of the two support portions 525 includes a support portion main body 81 and two guide portions 97a, 97b that guide both circumferential sides of the support portion main body 81. The support portion main body 81 is a rectangular parallelepiped block that extends in a direction perpendicular to the direction in which they face each other when viewed in the vehicle width direction. Cam portions 82 are formed on opposing side portions of the support portion main body 81. The cam portion 82 has a plurality of (for example, three in the fifth embodiment) step portions 82a, 82b, 82c (first step portion 82a, second step portion 82b, third step portion 82c) that are at different distances from the axle 2.

[0129] The first step 82a of each of the two support portions 525 is formed closest to the adjusting block 72. The second step 82b is disposed on the spring seat 93 side of the first step 82a. The second step 82b is formed in a position closer to the axle 2 than the first step 82a. The third step 82c is disposed on the spring seat 93 side of the second step 82b. The third step 82c is formed in a position closer to the axle 2 than the second step 82b. The compression coil spring 24 provided between the support portion 525 and the spring seat 22 of the brake shoe 23 causes the shift lever 96 to constantly abut against each of the steps 82a to 82c.

[0130] The two guide portions 97a, 97b allow sliding movement in opposing directions of the support portion main body 81. In other words, the two guide portions 97a, 97b allow the support portion main body 81 to slide in directions toward and away from the spring seat 22 of the brake shoe 23.

[0131] With this configuration, when the rotational position of the adjustment piece 72 is the first rotational position, of the three distances La to Lc, the first distance La is the shortest, and therefore the slide block 91 is closest to the adjustment piece 72. In this state, the shift lever 96 abuts against the first step portion 82a of the support portion 525. This state corresponds to the first-stage brake described above.

[0132] Next, the adjustment top 72 is rotated, for example, clockwise (CW) in FIG. 18, to set the rotation position of the adjustment top 72 to the second rotation position. In this case, the second distance Lb is longer than the first distance La, so the shift lever 96 abuts against the second step portion 82b of the support portion 525. This state corresponds to the second-stage braking described above. 18, the adjustment top 72 is rotated further clockwise (CW) to set the rotation position of the adjustment top 72 to the third rotation position. In this case, the third distance Lc is longer than the second distance Lb, so the shift lever 96 abuts against the third step portion 82c of the support portion 525. This state corresponds to the third brake described above.

[0133] When the adjusting top 72 is further rotated clockwise (CW) in Fig. 18, the rotational position of the adjusting top 72 returns to the first rotational position, and the first brake is provided. In contrast, when the adjusting top 72 is rotated counterclockwise (CCW) from the third rotational position (CCW) in Fig. 18, the rotational position of the adjusting top 72 returns to the second rotational position, and the second brake is provided. Similarly, when the adjusting top 72 is in the first rotation position, it can be changed to either the second rotation position or the third rotation position at once depending on the rotation direction of the adjusting top 72. When the adjusting top 72 is in the second rotation position, it can be changed to either the first rotation position or the third rotation position at once depending on the rotation direction of the adjusting top 72.

[0134] As described above, the fifth embodiment provides the same effects as the first embodiment. In addition, the first, second, and third stage brakes can be quickly switched depending on the rotation direction of the adjustment piece 72. This makes it possible to provide a centrifugal brake unit 513 that is even easier to use.

[0135] In the above-described fifth embodiment, the slide block 91 includes the rod-shaped shift lever 96 extending in the opposing direction of the two support portions 525, and the shift-side spring seat 94 and contact pin 95 integrally molded in the longitudinal center of the shift lever 96. However, this is not limited thereto, and the slide block 91 may have any structure as long as it slides along the straight line Li according to the distances La, Lb, and Lc when the adjustment piece 72 is rotated. The slide movement may switch the steps 82a to 82c against which the shift lever 96 abuts.

[0136] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above embodiment, a walking cart 101 that assists a user in walking has been described as a vehicle. However, the present invention is not limited to this, and the vehicle may be any vehicle that includes a body 102 and wheels 103 that are rotatably supported on the body 102. For example, the vehicle may be a cart that is pushed by a person to transport luggage, a stroller for carrying an infant, or the like.

[0137] Among the embodiments disclosed in this specification, those that are comprised of multiple objects may be integrated, and conversely, those that are comprised of a single object may be separated into multiple objects. Regardless of whether they are integrated, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0138] 1,201,301,401,501…Speed ​​control device 2...Axle (shaft, axis of rotation) 11...Brake drum 11b...Cylindrical part (tube part) 22...Spring seat 22a…Contact surface 23...Brake shoe 24...Compression coil spring (compression spring) 25...Support part 25d...Limiting convex part (Limiting part, convex part) 25e…support surface 26,426...Shift cam (shift part, cam) 27...Adjustment gear (adjustment part) 30...Pad 31...Support shaft (swing axis) 51...Limiting convex part (limiting part, convex part) 52...Limiting locking portion (limiting portion, convex portion) 53...Gear side locking claw (limiting portion, convex portion) 54...Brake side locking claw (restriction part, convex part) 102...Body 103...Wheel (rotating body)

Claims

1. A speed suppression device that suppresses the rotation speed of a rotating body rotatably supported on a shaft portion, a brake drum provided integrally with the shaft portion and having a cylindrical portion; a brake shoe that is displaced by a centrifugal force generated in response to rotation of the rotating body and that comes into contact with an inner peripheral surface of the cylindrical portion to suppress rotation of the rotating body; a limiting portion that limits the displacement of the brake shoe; Equipped with Speed ​​restraint device.

2. a compression spring that contacts the brake shoe and applies elastic force to the brake shoe to control the amount of displacement of the brake shoe; a support portion provided on the opposite side of the compression spring from the brake shoe and configured to support the compression spring; a shift unit that displaces the support unit in a compression direction of the compression spring to reduce the pressing force of the brake shoe against the cylindrical portion, and displaces the support unit in an extension direction of the compression spring to increase the pressing force of the brake shoe against the cylindrical portion; Preparation, the limiting portion includes a protrusion that protrudes from the support portion toward the brake shoe on the opposite side of the compression spring, the protrusion contacts the brake shoe to prevent displacement of the brake shoe when the displacement amount of the support portion in the compression direction of the compression spring reaches a certain amount. The speed control device according to claim 1 .

3. a compression spring that contacts the brake shoe and applies elastic force to the brake shoe to control the amount of displacement of the brake shoe; a support portion provided on the opposite side of the compression spring from the brake shoe and configured to support the compression spring; a shift unit that displaces the support unit in a compression direction of the compression spring to reduce the pressing force of the brake shoe against the cylindrical portion, and displaces the support unit in an extension direction of the compression spring to increase the pressing force of the brake shoe against the cylindrical portion; Preparation, the limiting portion includes a convex portion that protrudes from the brake shoe toward the support portion on the opposite side of the compression spring, the protrusion comes into contact with the support portion to prevent displacement of the brake shoe when the amount of displacement of the support portion in the compression direction of the compression spring reaches a certain amount. The speed control device according to claim 1 .

4. a compression spring that contacts the brake shoe and applies elastic force to the brake shoe to control the amount of displacement of the brake shoe; a support portion provided on the opposite side of the compression spring from the brake shoe and configured to support the compression spring; a shift unit that displaces the support unit in a compression direction of the compression spring to reduce the pressing force of the brake shoe against the cylindrical portion, and displaces the support unit in an extension direction of the compression spring to increase the pressing force of the brake shoe against the cylindrical portion; Preparation, the limiting portion includes a convex portion provided on the shift portion, the protrusion contacts the brake shoe to prevent displacement of the brake shoe when the shift unit is operated so that the displacement amount of the compression spring in the support unit in the compression direction reaches a certain amount. The speed control device according to claim 1 .

5. the shift portion includes a cam that rotates around the rotation axis of the rotating body and has the support portion disposed on an outer peripheral surface thereof, The cam is provided with the protrusion. The speed control device according to claim 4.

6. The shift unit is a cam that rotates around the rotation axis of the rotating body and has the support portion disposed on its outer peripheral surface; an adjustment unit that rotates around another rotation axis that is parallel to the rotation axis of the rotating body and adjusts the rotation position of the cam; Including, The adjustment portion is provided with the convex portion. The speed control device according to claim 4.

7. The rotating body includes a wheel provided on the body of the handcart. The speed control device according to claim 1 .

8. The car body and a wheel rotatably supported on an axle of the vehicle body; a speed suppression device that suppresses the rotational speed of the wheel; Equipped with The speed suppression device is a brake drum provided integrally with the axle and having a cylindrical portion; a brake shoe that is displaced by a centrifugal force generated in response to rotation of the wheel and that contacts an inner peripheral surface of the cylindrical portion to suppress rotation of the wheel; a limiting portion that limits the displacement of the brake shoe; Equipped with vehicle.

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