Centrifugal brake

Abstract

To provide a novel centrifugal brake with infinitely adjustable braking force.SOLUTION: A pair of adjusting members 26a and 26b, which can rotate around an adjusting axis o2 intersecting the axis of rotation o1, are connected so that their inner surfaces face each other in the direction of the adjusting axis o2, and the inner surfaces of the connected pair of adjusting members 26a and 26b contact and slide on the outer surface of a weight 18 to define a cylindrical sliding inner surface 32, and a plurality of regions (main adjustment pieces 38x, 38y, 38z) with different friction coefficients are circumferentially adjacent to each other around the adjustment axis o2 on the inner surfaces of each of the pair of adjustment members 26a and 26b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a centrifugal brake, in particular to a centrifugal brake in which the magnitude of the braking force can be steplessly adjusted by a required operation. [Background technology]

[0002] Blinds are sometimes installed near windows in rooms to avoid sunlight. The blinds have slats extending horizontally. Many slats are arranged vertically, and the many slats are connected vertically by lifting and lowering cords (sometimes called operating cords). The blinds further include a winding mechanism arranged above the uppermost slat and a bottom rail (sometimes called a bottom pipe or weight bar) arranged below the lowermost slat, and one end of the lifting and lowering cord is connected to the winding mechanism and the other end to the bottom rail. In such blinds, the bottom rail is raised by operating the winding mechanism to wind up the lifting and lowering cord, and the bottom rail is held at any raised position by operating an appropriate locking mechanism provided in the winding mechanism. The bottom rail is lowered by releasing the operation of the locking mechanism. Here, since the bottom rail falls freely when the operation of the locking mechanism is released, an appropriate brake mechanism may be incorporated in the winding mechanism to reduce the speed of its descent. A well-known centrifugal brake is often used as such a brake mechanism.

[0003] The following Patent Document 1 discloses, as an example of a centrifugal brake, a centrifugal brake that includes a cylindrical housing having an inner peripheral surface with a circular cross section and a rotor that rotates inside the housing, the rotation axis of the rotor is the same as the central axis of the inner peripheral surface of the housing, the rotor has a support shaft that extends parallel to the rotation axis at a position eccentric to the rotation axis, a weight is rotatably supported on the support shaft, and when the rotor rotates, the weight rotates and the outer surface of the weight abuts and slides against the inner surface of the housing. The centrifugal force presses the outer surface of the weight against the inner peripheral surface of the housing, and the normal force generated between the outer surface of the weight and the inner peripheral surface of the housing is increased, so that the braking force caused by friction is also increased. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Publication number 1-45353 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, in the centrifugal brake disclosed in Patent Document 1, the magnitude of the braking force cannot be adjusted, and therefore, when this centrifugal brake is used as the braking mechanism of the above-mentioned blinds, the falling speed of the slats cannot be adjusted according to the user's preference. Also, when changing the braking force according to the weight of the slats, it is necessary to prepare in advance a number of centrifugal brakes with different braking forces, which makes inventory management of centrifugal brakes complicated.

[0006] Incidentally, in the specification and drawings of Japanese Patent Application No. 2020-187961 filed prior to this application, the present inventor proposed a centrifugal brake in which a plurality of weights are arranged in series in the axial direction, an adjustment member that rotates integrally with the rotor and can advance and retreat in the axial direction relative to the rotor is combined with the rotor, and the adjustment member can selectively advance between the inner peripheral surface of the housing and the outer peripheral surface of the weight by adjusting the axial position of the adjustment member relative to the rotor (hereinafter referred to as the "preceding centrifugal brake"). According to this centrifugal brake, by adjusting the axial position of the adjustment member relative to the rotor, it is possible to change the number of weights whose outer peripheral surface (of the weight) abuts against the inner peripheral surface of the adjustment member and is prevented from abutting against the inner peripheral surface of the housing when the rotor rotates, thereby making it possible to adjust the magnitude of the braking force applied to the rotor in stages.

[0007] It was found that the above-mentioned pre-emptive centrifugal brake was not fully satisfactory and presented the further problem that the braking force was adjusted in stages with the pre-emptive centrifugal brake, making fine adjustment of the braking force impossible.

[0008] The present invention has been made in view of the above circumstances, and its main technical object is to provide a new and improved centrifugal brake in which the braking force can be adjusted steplessly. [Means for solving the problem]

[0009] After careful consideration, the inventors discovered that the above-mentioned main technical objective can be achieved by connecting a pair of adjustment members, which are rotatable around an adjustment axis that intersects the rotation axis, so that their respective inner surfaces face each other at a distance in the adjustment axis direction, defining a cylindrical sliding inner surface against which the outer surface of the weight abuts and slides against the inner surfaces of the connected pair of adjustment members, and partitioning a number of areas with different friction coefficients adjacent to each other in the circumferential direction around the adjustment axis on the inner surface of each of the pair of adjustment members.

[0010] That is, according to the present invention, a centrifugal brake that achieves the above-mentioned main technical object is provided, which comprises a housing and a rotor that rotates inside the housing, The rotating body has a support shaft extending parallel to the rotation shaft at a position eccentric to the rotation shaft, and a weight is rotatably supported on the support shaft, In a centrifugal brake in which, when the rotating body rotates, the weight rotates and an outer surface of the weight abuts against and slides on an inner surface of the housing, the housing includes a pair of adjustment members rotatable around an adjustment axis intersecting the rotation axis, inner surfaces of the pair of adjustment members are arranged opposite to each other at a distance in the adjustment axis direction, and a cylindrical sliding inner circumferential surface is defined on the inner surfaces of the pair of adjustment members against which an outer surface of the weight abuts and which can slide freely; The present invention provides a centrifugal brake, characterized in that an inner surface of each of the pair of adjustment members is provided with a plurality of regions having different friction coefficients that are adjacently defined in a circumferential direction around the adjustment shaft.

[0011] Preferably, each of the pair of adjustment members is constructed by combining a plurality of plate-shaped adjustment pieces, and each of the plurality of plate-shaped adjustment pieces is formed of a material having a different friction coefficient. It is preferable that the cross-sectional shape of the sliding inner peripheral surface is an arc shape and the vertical cross-sectional shape is a circle. It is preferable that the adjustment axis is perpendicular to the rotation axis. Preferably, the housing further includes a pair of movable housing pieces to which each of the pair of adjustment members is fixed separately and coupled to each other, and a pair of fixed housing pieces which rotatably hold the rotating body and rotatably hold the pair of movable housing pieces coupled to each other. In this case, it is preferable that a rubber washer is disposed between the pair of fixed housing pieces and one of the pair of movable housing pieces. Furthermore, an operation unit is provided on one of the pair of movable housing pieces, and a rubber washer is disposed between the pair of fixed housing pieces. Piece It is convenient for one or both of the movable housing pieces to be provided with a limiting piece for limiting the range of rotation of the movable housing piece. Effect of the Invention

[0012] In the centrifugal brake of the present invention, a cylindrical sliding inner peripheral surface against which the outer surface of the weight abuts and slides is defined on the inner surface of a pair of adjustment members that can rotate around an adjustment axis that intersects with the rotation axis, and a plurality of regions with different friction coefficients are defined adjacent to each other in the circumferential direction around the adjustment axis on the inner surface of each of the pair of adjustment members. Therefore, by rotating the pair of adjustment members around the adjustment axis, the region of the inner surface of the pair of adjustment members against which the outer surface of the weight abuts is changed, and the magnitude of the frictional resistance that the weight receives from the adjustment members can be adjusted. Since the above-mentioned regions are defined adjacent to each other in the circumferential direction around the adjustment axis, if the outer surface of the weight abuts across the above-mentioned regions on the inner surface of the adjustment member, the magnitude of the frictional resistance that the weight receives from the adjustment members can be adjusted steplessly. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing the overall configuration of a centrifugal brake constructed according to the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the centrifugal brake shown in FIG. 1 , showing each component part. [Diagram 3] FIG. 2 is a diagram showing a rotor of the centrifugal brake shown in FIG. 1 by itself. [Figure 4] FIG. 2 is a front view of the inner surface of the adjustment member shown in FIG. 1. [Diagram 5] 2 is a view showing one of a pair of housing pieces of the centrifugal brake shown in FIG. 1 alone. FIG. [Figure 6] 2 is a view showing the other of the pair of housing pieces of the centrifugal brake shown in FIG. 1 alone. FIG. [Figure 7] FIG. 2 is a view showing a stationary housing piece of the centrifugal brake shown in FIG. 1 alone. [Figure 8] 2 is a cross-sectional view taken along line AA in FIG. 1 when the rotor is rotating. [Figure 9-1] 2 is a diagram showing a state in which an adjustment member is rotated around an adjustment shaft in the centrifugal brake shown in FIG. 1; [Figure 9-2] 2 is a diagram showing a state in which an adjustment member is rotated around an adjustment shaft in the centrifugal brake shown in FIG. 1; [Figure 9-3]2 is a diagram showing a state in which an adjustment member is rotated around an adjustment shaft in the centrifugal brake shown in FIG. 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the accompanying drawings, which show preferred embodiments of a centrifugal brake constructed in accordance with the present invention.

[0015] 1 and 2, a centrifugal brake generally designated by the numeral 2 includes a housing 4 and a rotor 6 that rotates inside the housing 4. The rotation axis of the rotor 6 is designated by o1.

[0016] For convenience, the rotor 6 will be described first with reference to FIG. 1, FIG. 2, and FIG. 3 before the housing 4. The rotor 6 is made of an appropriate synthetic resin and includes a rotary main shaft 8 that has a circular cross section and extends linearly in the axial direction along the rotary axis o1 (in this paragraph and the next paragraph, unless otherwise specified, "axial direction" refers to the axial direction along the rotary axis o1, and "circumferential direction" refers to the circumferential direction based on the rotary axis o1). Disk-shaped flanges 10 are provided at both axial ends of the rotary main shaft 8, and one of the flanges 10 is provided with a connecting portion 12 that extends linearly on the opposite side of the rotary main shaft 8 in the axial direction. The cross-sectional shape of the connecting portion 12 is a shape in which a part of the circular outer circumferential surface is cut out linearly, and the rotor 6 is connected to an external device (not shown) such as a blind winding mechanism via the connecting portion 12. A pair of circular support plates 14 are provided at an axially intermediate portion of the rotary main shaft 8 with an axial gap therebetween. The pair of support plates 14 are connected to each other at their outer peripheries by a support shaft 16 extending parallel to the rotation axis o1. In other words, the rotor 6 has the support shaft 16 extending parallel to the rotation axis o1 at a position eccentric to the rotation axis o1. The support shaft 16 is supported at both ends by the pair of support plates 14, so that the strength of the support shaft 16 is high. In the illustrated embodiment, two support shafts 16 are provided at an angular interval of 180 degrees in the circumferential direction, and the cross section of the support shaft 16 has a required shape.

[0017] Continuing the explanation with reference to Figs. 1 and 2, a metal weight 18 is pivotally supported on the support shaft 16. In the illustrated embodiment, two support shafts 16 are provided, and the weight 18 is pivotally supported on each of the two support shafts 16. The weight 18 has an arc shape and a required width in the axial direction. A bearing groove 20 is formed at one end of the outer circumferential surface of the weight 18, which penetrates linearly in the axial direction, and the weight 18 is attached to the rotating body 6 by fitting the bearing groove 20 to the support shaft 16 of the rotating body 6. For the cross-sectional shapes of the support shaft 16 and the bearing groove 20 and the method of attaching the weight 18 to the rotating body 6, please refer to Japanese Patent No. 7052122, which was filed by the present inventor prior to this application and has already been patented. A mounting groove 22 is formed at the circumferential middle portion of the outer circumferential surface of the weight 18, which penetrates linearly in the axial direction. A synthetic resin friction shoe 24 is attached to the mounting groove 22 in a freely replaceable manner.

[0018] Continuing to describe the housing 4 with reference to FIGS. 1 and 2, the housing 4 includes a pair of adjustment members 26a and 26b. In the illustrated embodiment, the housing 4 also includes a pair of movable housing pieces 28a and 28b and a pair of fixed housing pieces 30a and 30b. The pair of adjustment members 26a and 26b, the pair of movable housing pieces 28a and 28b, and the pair of fixed housing pieces 30a and 30b are all formed of an appropriate synthetic resin. The material of the pair of adjustment members 26a and 26b will be further mentioned later. Each of the pair of adjustment members 26a and 26b is rotatable around an adjustment axis o2 intersecting with the rotation axis o1, and the respective inner surfaces are arranged opposite to each other with a gap in the direction of the adjustment axis o2. In the illustrated embodiment, the adjustment axis o2 is perpendicular to the rotation axis o1, and each of the pair of adjustment members 26a and 26b has the same hemispherical shape. When the pair of adjustment members 26a and 26b are assembled, a spherical internal space is defined, and the weight 18 is disposed in the internal space. As a result, a sliding inner peripheral surface 32 is defined on the inner surface of the assembled pair of adjustment members 26a and 26b, against which the outer surface of the weight 18 abuts and slides when the weight 18 rotates, as described below (see also FIG. 9-1). In the illustrated embodiment, each of the pair of adjustment members 26a and 26b has the same hemispherical shape, so that the transverse cross-sectional shape (cross-sectional shape when cut horizontally in FIG. 9-1(b)) of the sliding inner peripheral surface 32 is an arc shape, and the longitudinal cross-sectional shape (cross-sectional shape when cut vertically in FIG. 9-1(b)) is a circle. Two arc-shaped notches 36 are formed on the annular end edge of each of the pair of adjustment members 26a and 26b at an angular interval of 180 degrees around the adjustment axis o2.

[0019] A plurality of regions with different friction coefficients are defined adjacent to each other in the circumferential direction around the adjustment axis o2 on the inner surface of each of the pair of adjustment members 26a and 26b. In the illustrated embodiment, each of the pair of adjustment members 26a and 26b is configured by combining a plurality of plate-shaped adjustment pieces, and the above-mentioned regions are defined by forming each of the plate-shaped adjustment pieces from materials with different friction coefficients. The adjustment pieces include a main adjustment piece 38 and an auxiliary adjustment piece 40 (as will be described later, in the drawings, x to z are added after the numbers of each material, but when all materials are described collectively, the above x to z are omitted). With reference to FIG. 2 and FIG. 4, the inner and outer surfaces of the main adjustment piece 38 and the auxiliary adjustment piece 40 are both isosceles triangles when viewed from the front, that is, in the axial direction along the adjustment axis o2 (in this paragraph to paragraph 0022, unless otherwise specified, the "axial direction" refers to the axial direction along the adjustment axis o2, and the "circumferential direction" refers to the circumferential direction based on the adjustment axis o2), and both the longitudinal and transverse cross-sectional shapes are arc shapes. Therefore, if the main adjustment piece 38 and the auxiliary adjustment piece 40 are arranged adjacent to each other in the circumferential direction, they will have a hemispherical shape. The auxiliary adjustment piece 40 is somewhat wider than the main adjustment piece 38 and has a somewhat shorter vertical cross-sectional length. When the inner surface of each of the main adjustment pieces 38 and the auxiliary adjustment piece 40 is viewed from the front, three main adjustment pieces 38 arranged adjacent to each other in the circumferential direction are arranged in pairs at an angular interval of 180 degrees in the circumferential direction, and two auxiliary adjustment pieces 40 are arranged adjacent to each other in the circumferential direction on both sides of the three main adjustment pieces 38 in the circumferential direction, and a notch 36 is defined at the circumferential portion where the auxiliary adjustment pieces 40 are arranged. Two holding protrusions 42 each having a circular cross section protruding in the axial direction are provided at intervals on the outer surface of the main adjustment piece 38 and the auxiliary adjustment piece 40, and the main adjustment piece 38 and the auxiliary adjustment piece 40 are supported by the movable housing piece 28a or 28b as part of the adjustment member 26a or 26b via the holding protrusions 42. In the illustrated embodiment, the adjustment pieces (i.e., the main adjustment piece 38 and the auxiliary adjustment piece 40) are made of three types of materials x to z with different friction coefficients, and in the drawing, each material is numbered x to z. Material x is, for example, polybutylene terephthalate (PBT), and the adjustment piece made from this has a relatively small friction coefficient. Material y is, for example, polyacetal (POM), and the adjustment piece made from this has a relatively medium friction coefficient.The material z is, for example, a thermoplastic ester-based elastomer material, and the adjustment piece formed therefrom has a relatively large coefficient of friction. As clearly shown in Fig. 4, when the inner surface of the adjustment members 26a and 26b is viewed from the front, the main adjustment pieces 38x to 38z are arranged so as to be located on both sides in the diametrical direction (therefore, the circumferential arrangement of the three main adjustment pieces 38x to 38z arranged in pairs at an angular interval of 180 degrees in the circumferential direction is the same when viewed from one side in the circumferential direction), and the auxiliary adjustment pieces 40 are arranged (auxiliary adjustment pieces 40x and 40z) made of the same material as the main adjustment piece 38 adjacent in the circumferential direction.

[0020] Explaining with reference to FIG. 5 together with FIG. 1 and FIG. 2, the inner surface of the movable housing piece 28a is hemispherical, and its curvature corresponds to the curvature of the outer surface of the adjustment member 26a (and 26b). A plurality of bottomed holding holes 44 into which the holding protrusions 42 of the adjustment member 26a are inserted are formed on the inner surface of the movable housing piece 28a corresponding to the holding protrusions 42, and the movable housing piece 28a holds the adjustment member 26a from its outer surface (rear surface). The outer surface of the movable housing piece 28a is divided into a bottom portion 46 which is a part of a sphere, and a peripheral wall 47 which extends in the axial direction from the periphery of the bottom portion 46. The outer surface of the bottom portion 46 is parallel to the inner surface of the movable housing piece 28a. The peripheral wall 47 is generally cylindrical, but two arc-shaped notches 50 extending in the circumferential direction are formed at the free end in the axial direction at an angular interval of 180 degrees in the circumferential direction. The circumferential length of the notch 50 corresponds to the circumferential length of the notch 36 formed in the adjustment member 26a. The circumferential region of the peripheral wall 47 where the notch 50 is not formed forms the locking portion 48. Therefore, there are two locking portions 48 at an angular interval of 180 degrees in the circumferential direction. At both circumferential ends of the locking portion 48, a circumferential locking rib 52 having a rectangular cross section is provided, which protrudes radially outward from the outer circumferential surface of the peripheral wall 47 and extends linearly in the axial direction. The circumferential locking rib 52 extends from the axially open side edge 50a of the notch 50 beyond the axially closed side edge 50b to the axially intermediate portion of the peripheral wall 47 as viewed in the axial direction. An axial locking recess 54 extending linearly in the circumferential direction is also formed at both circumferential ends of the outer circumferential surface of the locking portion 48.

[0021] Explaining with reference to FIG. 6 together with FIG. 1 and FIG. 2, the movable housing piece 28b includes a flat operating portion 56 arranged perpendicular to the axial direction, and a cylindrical main portion 58 extending axially from the center of one side of the operating portion 56. A plurality of irregularities 60 are formed repeatedly in the circumferential direction on the outer peripheral surface of the operating portion 56. Such irregularities 60 include protruding protrusions 62 that protrude radially outwardly more than other protrusions. A pair of protruding protrusions 62 are formed adjacent to each other in the circumferential direction on both sides in the diametric direction, that is, four protruding protrusions 62 are formed in total. The inner surface of the main portion 58 is hemispherical, and its curvature corresponds to the curvature of the outer surface of the adjustment member 26b (and 26a). A plurality of bottomed holding holes 64, through which the holding protrusions 42 of the adjustment member 26b are inserted, are formed in the inner surface of the main portion 58 in correspondence with the holding protrusions 42, and the movable housing piece 28b holds the adjustment member 26b from the outer surface (rear surface). Two arcuate notches 66 extending in the circumferential direction are formed at the axial free end of the main portion 58 at an angular interval of 180 degrees. The circumferential length of the notches 66 corresponds to the circumferential length of the notch 36 formed in the adjustment member 26b and the notch 50 formed in the movable housing piece 28a. A plate-shaped locked piece 68 extending linearly in the axial direction beyond the axial free end of the main portion 58 is attached to the circumferential middle part of the outer circumferential surface of the two arcuate parts remaining between the two notches 66. Axial locking protrusions 70 extending linearly in the circumferential direction are formed on both circumferential ends of the inner circumferential surface of the extended end of the locked piece 68. In addition, a circular arc-shaped shoulder surface 71 facing the operating portion 56 in the axial direction is formed at the base end of the locked piece 68.

[0022] 1 and 2 and FIG. 7, the pair of fixed housing pieces 30a and 30b are identical in shape and are composed of a rectangular end plate 72 arranged perpendicular to the axial direction and a side wall 74 having a semicircular cross section extending linearly from the end plate 72 in the axial direction, and the end face extending in the axial direction of the side wall 74 is located on the same plane as the end face of the adjacent end plate 72. The axial bottom surface of the end plate 72 defined on the inside of the side wall 74 is a part of a sphere, the curvature of which corresponds to the curvature of the outer surface of the bottom part 46 of the movable housing piece 28a. The side wall 74 is connected to the end plate 72 and is divided into a base end 76 having a relatively large outer diameter and a main part 78 having an outer diameter smaller than that of the base end 76. The inner surface of the base end 76 has an arc-shaped groove 80 formed by locally increasing the inner diameter and continuing in the circumferential direction. The cross section of the groove 80 is rectangular. A circular communication hole 82 penetrating in the radial direction (i.e., the axial direction along the rotation axis o1) is formed in the circumferential center portion of the main portion 78 of the side wall 74, and a C-shaped support wall 84 protruding radially outward is formed on the outer circumferential surface of the main portion 78 along the periphery of the communication hole 82. The inner periphery of the support wall 84 is located slightly inside the periphery of the communication hole 82, and the outer circumferential surface of the support wall 84 is locally connected to the base end portion 76 at its circumferential center portion. A pair of additional portions 85 extending in the axial direction from the base end portion 76 are also formed on the outer circumferential surface of the main portion 78. The circumferential inner side surface of each of the pair of additional portions 85 is connected to the outer circumferential surface of the support wall 84, and a limiting piece 86 extending linearly in the axial direction is attached to each of the circumferential inner ends of the pair of additional portions 85. The limiting piece 86 extends in the axial direction beyond the axial free end of the main portion 78. Such limiting pieces 86 are formed on both circumferential sides of the communication hole 82. That is, a pair of limiting pieces 86 are formed. An arc-shaped shoulder surface 88 is formed on the inner peripheral surface of the main portion 78, extending circumferentially across the communicating hole 82 and facing the axial bottom side of the main portion 78. Engagement claws 90 and engagement frames 92 are formed on the outer surfaces of the end plate 72 and the side wall 74, respectively, and the pair of fixed housing pieces 30a and 30b are joined together by making the inner surfaces of the side walls 74 of the pair of fixed housing pieces 30a and 30b face each other in a direction perpendicular to the axial direction (i.e., the axial direction along the rotation axis o1) and engaging the engagement claws 90 and engagement frames 92 formed on each of them.When the pair of stationary housing pieces 30a and 30b are joined together, an accommodation space having a circular cross section is defined inside the joined pair of stationary housing pieces 30a and 30b. The bottom surface of the accommodation space is a part of a sphere, and the curvature thereof is the same as the curvature of the outer surface of the bottom portion 46 of the movable housing piece 28a. The groove 80 is also annular and continues in the circumferential direction.

[0023] The housing 4 and the rotating body 6 described above are combined as follows. To explain mainly with reference to Fig. 2, first, a pair of movable housing pieces 28a and 28b are arranged on both sides of the weight 18 attached to the rotating body 6, on both sides of an adjustment axis o2 that intersects with the rotation axis o1 (orthogonal in the illustrated embodiment). Each of the pair of movable housing pieces 28a and 28b is arranged in a state in which the inner surface of the adjustment member 26a held by the movable housing piece 28a and the inner surface of the adjustment member 26b held by the movable housing piece 28b face each other on the adjustment axis o2.

[0024] Next, the notch 50 of the movable housing piece 28a and the notch 36 of the adjustment member 26a, and the notch 66 of the movable housing piece 28b and the notch 36 of the adjustment member 26b are aligned with the main rotation shaft 8 of the rotating body 6 to bring the pair of movable housing pieces 28a and 28b close to each other on the adjustment axis o2, and the weight 18 is embraced by the inner surfaces of the pair of adjustment members 26a and 26b. When the pair of movable housing pieces 28a and 28b are combined in this manner, a pair of arc-shaped windows 94 through which the main rotation shaft 8 of the rotating body 6 passes are defined by the notches 36, 50 and 66, as shown in Figures 9-1 to 9-3. Furthermore, when the pair of movable housing pieces 28a and 28b are brought close to each other as described above, the locked piece 68 of the movable housing piece 28b enters between two circumferential locking ribs 52 adjacent in the circumferential direction formed on the movable housing piece 28a, and the axial locking protrusion 70 formed on the inner surface of the locked piece 68 rides up onto the outer surface of the locking portion 48 of the peripheral wall 47 and then fits into the axial locking recess 54. This restricts the circumferential and axial movements of the movable housing piece 28b relative to the movable housing piece 28a, and the pair of movable housing pieces 28a and 28b are joined together.

[0025] Thereafter, the pair of movable housing pieces 28a and 28b, which are joined together while embracing the rotating body 6, are brought closer to each other from both sides of the rotation axis o1, and the connecting portion 12 of the rotating body 6 is brought into communication with the communication hole 82 of the fixed housing piece 30b, and the two flanges 10 are supported in the direction of approaching each other from both axial sides of the rotation axis o1 by the support walls 84 formed on each of the pair of fixed housing pieces 30a and 30b. Thus, the rotating body 6 is supported by the pair of fixed housing pieces 30a and 30b to be rotatable around the rotation axis o1. Additionally, the outer surface of the bottom portion 46 of the movable housing piece 28a faces the axial bottom surface defined on the inner side of the side wall 74 of each end plate 72 of the pair of fixed housing pieces 30a and 30b, and the pair of movable housing pieces 28a and 28b are supported by the pair of fixed housing pieces 30a and 30b so as to be rotatable about the adjustment axis o2. In the illustrated embodiment, a rubber washer 96 is disposed between the pair of fixed housing pieces 30a and 30b and the movable housing piece 28a. The rubber washer 96 has an annular shape and is disposed in the groove 80. The shoulder surface 71 of the engaging piece 68 of the movable housing piece 28b engages with the shoulder surface 88 of the pair of fixed housing pieces 30a and 30b, thereby preventing the pair of movable housing pieces 28a and 28b from moving in the direction of the adjustment axis o2 relative to the pair of fixed housing pieces 30a and 30b and falling off.

[0026] As can be understood by comparing the AA cross-sectional view of Fig. 1 with Fig. 8, when the rotor 6 rotates in the centrifugal brake 2, the weight 18 journaled on the support shaft 16 of the rotor 6 rotates, and the outer surface of the weight 18, in the illustrated embodiment, the friction shoe 24, comes into contact with and slides against the inner surface (sliding inner circumferential surface 32) of the housing 4. A braking force acts on the rotor 6 due to this sliding.

[0027] In the state shown in Figure 1, the one of a pair of protruding convex portions 62 formed on the operating portion 56 of the movable housing piece 28b, which is located on the clockwise side (in the upper right diagram of Figure 1; the same applies below), abuts against the one of a pair of limiting pieces 86 formed on each of the side walls 74 of the fixed housing pieces 30a and 30b, which is located on the counterclockwise side, thereby preventing the movable housing piece 28b and the movable housing piece 28a integral with it from rotating clockwise around the adjustment axis o2 relative to the pair of fixed housing pieces 30a and 30b. FIG. 9-1 shows the same state as that shown in FIG. 1, and FIG. 9-1(a) shows the same view as the upper right view of FIG. 1, FIG. 9-1(b) shows the rotor 6 in the BB cross section of FIG. 1 with a two-dot chain line, the weight 18 is omitted, and the sliding inner peripheral surface 32 is indicated in light ink, and FIG. 9-1(c) shows a perspective view with the fixed housing piece 30b omitted (the same applies to (a) to (c) in FIG. 9-2 and FIG. 9-3 described later). As shown in FIG. 9-1(c), the rotating main shaft 8 of the rotating body 6 is located at one end of the window 94 in the circumferential direction. The rotating main shaft 8 is not in contact with the pair of movable housing pieces 28a and 28b. When the rotating body 6 rotates in the state shown in Figure 9-1, the sliding inner surface 32 along which the outer surface of the weight 18 slides against the inner surfaces of the pair of adjustment members 26a and 26b is dominated by the inner surface of the main adjustment piece 38x, which has a relatively small coefficient of friction, as can be understood by referring to Figure 9-1(b), and therefore the frictional force, or in other words, resistance, that the outer surface of the weight 18 receives from the sliding inner surface 32 is small.

[0028] Fig. 9-2 shows a state in which the operating portion 56 of the movable housing piece 28b has been rotated somewhat counterclockwise from the state shown in Fig. 9-1. In this state, as shown in Fig. 9-2(c), the main rotation shaft 8 of the rotating body 6 is located at the circumferential center of the window 94. Then, when the rotating body 6 rotates in the state shown in Fig. 9-2, as can be understood by referring to Fig. 9-2(b), the inner surface of the main adjustment piece 38y, which has a relatively medium friction coefficient, dominates the sliding inner circumferential surface 32, and therefore the frictional force, in other words, the resistance, that the outer surface of the weight 18 receives from the sliding inner circumferential surface 32 is medium.

[0029] FIG. 9-3 shows a state in which the operating portion 56 of the movable housing piece 28b is further rotated counterclockwise from the state shown in FIG. 9-2. In the state shown in FIG. 9-3, the other of the pair of protruding protrusions 62 formed on the operating portion 56 of the movable housing piece 28b, which is located on the counterclockwise side, abuts against the other of the pair of limiting pieces 86 formed on the side walls 74 of the fixed housing pieces 30a and 30b, which is located on the clockwise side, and the movable housing piece 28b and the movable housing piece 28a integral therewith are prevented from further rotating counterclockwise around the adjustment axis o2 relative to the pair of fixed housing pieces 30a and 30b, as shown in FIG. 9-3(c). At this time, the main rotation shaft 8 of the rotating body 6 is located at the other circumferential end of the window 94, and the main rotation shaft 8 is not in contact with the pair of movable housing pieces 28a and 28b. When the rotating body 6 rotates in the state shown in Figure 9-3, as can be understood by referring to Figure 9-3(b), the sliding inner surface 32 is dominated by the inner surface of the main adjustment piece 38z, which has a relatively large coefficient of friction, and therefore the frictional force, or in other words, resistance, that the outer surface of the weight 18 receives from the sliding inner surface 32 is large.

[0030] Therefore, in the centrifugal brake of the present invention, the cylindrical sliding inner peripheral surface 32 on which the outer surface of the weight 18 abuts and slides is defined by the inner surface of the pair of adjustment members 26a and 26b that can rotate around the adjustment axis o2 intersecting with the rotation axis o1, and a plurality of regions with different friction coefficients are defined adjacent to each other in the circumferential direction around the adjustment axis o2 on the inner surface of each of the pair of adjustment members 26a and 26b. Therefore, by rotating the pair of adjustment members 26a and 26b around the adjustment axis o2, the region on the inner surface of the pair of adjustment members 26a and 26b on which the outer surface of the weight 18 abuts is changed, and the magnitude of the frictional resistance that the weight 18 receives from the adjustment members 26a and 26b can be adjusted. Since the above-mentioned regions are defined adjacent to each other in the circumferential direction around the adjustment axis o2, if the outer surface of the weight 18 abuts across the plurality of the above-mentioned regions on the inner surface of the adjustment members 26a and 26b, the magnitude of the frictional resistance that the weight 18 receives from the adjustment members 26a and 26b can be adjusted steplessly. In addition, in the illustrated embodiment, a rubber washer 96 is arranged between the pair of fixed housing pieces 30a and 30b and the movable housing piece 28a, so that a certain degree of holding force acts on the pair of movable housing pieces 28a and 28b relative to the pair of fixed housing pieces 30a and 30b, thereby preventing as much as possible the pair of adjustment members 26a and 26b from unintentionally rotating around the adjustment axis o2 when the outer surface of the weight 18 slides along the sliding inner surface 32.

[0031] The centrifugal brake constructed according to the present invention has been described above in detail with reference to the attached drawings, but the present invention is not limited to the above-mentioned embodiment, and appropriate modifications and changes can be made within the scope of the present invention. For example, in the illustrated embodiment, each of the pair of adjustment members 26a and 26b is constructed by combining multiple plate-shaped adjustment pieces (main adjustment piece 38 and auxiliary adjustment piece 40), and the multiple plate-shaped adjustment pieces are formed of materials with different friction coefficients, but each of the pair of adjustment members may be constructed of a single plate-shaped adjustment piece and multiple areas with different friction coefficients may be defined by polishing the inner surface or applying paint of materials with different friction coefficients to the inner surface of the single plate-shaped adjustment piece. If each of the pair of adjustment members is constructed of a single adjustment piece and can be connected to each other by itself, the pair of movable housing pieces may be omitted. Also, if the communication hole 82 is open in the direction of the adjustment axis o2, instead of combining a pair of fixed housing pieces, a single fixed housing in the form of a combination of a pair of fixed housing pieces may be used. In the illustrated embodiment, each of the pair of adjustment members 26a and 26b is hemispherical, but it may be hemispherical (a shape obtained by cutting a rugby ball in the short direction at the center in the longitudinal direction). When each of the pair of adjustment members 26a and 26b is hemispherical, the cross section of the sliding inner circumferential surface is arc-shaped, and the vertical section is elliptical. Furthermore, the number and arrangement of the support shafts and the weights supported by them can be changed as appropriate. [Explanation of symbols]

[0032] 2: Centrifugal brake 4: Housing 6: Rotating body 16: Support shaft 18: Weight 26a and 26b: Adjustment members 32: Sliding inner surface 38x, 38y, 38z: Main adjustment piece (area) o1: Rotation axis o2: Adjustment axis

Claims

1. The rotor includes a housing and a rotor that rotates inside the housing. The rotating body has a support shaft extending parallel to the rotation shaft at a position eccentric to the rotation shaft, and a weight is rotatably supported on the support shaft, In a centrifugal brake in which, when the rotating body rotates, the weight rotates and an outer surface of the weight abuts against and slides on an inner surface of the housing, the housing includes a pair of adjustment members rotatable around an adjustment axis intersecting the rotation axis, inner surfaces of the pair of adjustment members are arranged opposite to each other at a distance in the adjustment axis direction, and a cylindrical sliding inner circumferential surface is defined on the inner surfaces of the pair of adjustment members against which an outer surface of the weight abuts and which can slide freely; A centrifugal brake, characterized in that an inner surface of each of the pair of adjustment members is defined with a plurality of regions having different friction coefficients adjacent to each other in a circumferential direction around the adjustment shaft.

2. 2. The centrifugal brake according to claim 1, wherein each of said pair of adjustment members is formed by combining a plurality of plate-shaped adjustment pieces, and said plurality of plate-shaped adjustment pieces are formed of materials having different friction coefficients.

3. 3. The centrifugal brake according to claim 1, wherein the inner sliding surface has a cross section that is arcuate and a vertical section that is circular.

4. 3. A centrifugal brake as claimed in claim 1 or 2, wherein the adjustment axis is perpendicular to the axis of rotation.

5. 3. The centrifugal brake according to claim 1, wherein the housing further includes a pair of movable housing pieces to which the pair of adjustment members are fixed and connected to each other, and a pair of fixed housing pieces which rotatably sandwich the rotating body and rotatably sandwich the pair of movable housing pieces which are connected to each other.

6. 6. The centrifugal brake of claim 5, further comprising a rubber washer disposed between said pair of stationary housing halves and one of said pair of movable housing halves.

7. The centrifugal brake according to claim 5, wherein one of the pair of movable housing pieces is provided with an operating portion, and one or both of the pair of fixed housing pieces is provided with a limiting piece that limits the rotation range of the movable housing piece.

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