Power transmission device

Abstract

To provide a power transmission device which can arbitrarily transmit or block a rotation force of an input member to an output member.SOLUTION: A power transmission device comprises centrifugal clutch means having a plurality of weight members which are movable to an outside-diameter side position from an inside-diameter position by a centrifugal force accompanied by the rotation of a clutch housing, and a pressure-contact member 12 for moving a drive-side clutch plate and a driven-side clutch plate in a direction in which the clutch plates pressure-contact with each other by the movement of the weight members to the outside-diameter position from the inside-diameter position. The weight members are constituted so as to make the drive-side clutch plate and the driven-side clutch plate pressure-contact with each other via the pressure-contact member 12 in a process in which the weight members move to the outside-diameter side position from the inside-diameter position, the pressure-contact member 12 has a circular body part and a plurality of protrusions K2 which are aligned in a circumferential direction of the body part, and the number of the plurality of protrusions K2 is an integer multiple of the number of the plurality of weight members, and the plurality of protrusions K2 are arranged while being separated from one another with respect to the circumferential direction.SELECTED DRAWING: Figure 11

Claims

1. A clutch member that rotates together with an input member that rotates with the driving force of a drive source, is housed in a clutch housing that holds multiple drive-side clutch plates, and is connected to an output member capable of rotating a wheel, A plurality of driven clutch plates and a pressure member capable of pressing the plurality of driven clutch plates are provided so as to be able to approach or move away from the clutch member and are arranged alternately with the drive clutch plates, The clutch housing comprises six weight members that are movable from an inner diameter position to an outer diameter position by centrifugal force accompanying the rotation of the clutch housing, and a pressure contact member provided so as to be in contact with the weight members and which moves in a direction that presses the drive-side clutch plate and the driven-side clutch plate together as the weight members move from the inner diameter position to the outer diameter position, and a centrifugal clutch means that presses the drive-side clutch plate and the driven-side clutch plate together when the weight members are in the outer diameter position to enable the driving force of the drive source to be transmitted to the wheel, and releases the pressure between the drive-side clutch plate and the driven-side clutch plate when the weight members are in the inner diameter position to block the transmission of the driving force of the drive source to the wheel. The weight member is configured to press against the drive-side clutch plate and the driven-side clutch plate via the pressure contact member during the process of the weight member moving from the inner diameter side position to the outer diameter side position. The aforementioned pressure-welding member is The ring-shaped main body, A plurality of protrusions that project from the main body in the axial direction of the output member, are arranged in the circumferential direction of the main body, and contact the weight member, It has six projections that protrude radially outward from the outer edge of the main body and are attached to the clutch housing, The protrusion is configured to transmit the thrust of the weight member to the contact member. The number of the multiple protrusions is twice the number of the multiple weight members. The two protrusions are configured to contact one of the weight members. The multiple protrusions are arranged to be spaced apart from each other in the circumferential direction. When the output member is viewed in the axial direction, all straight lines passing through the center of the main body and the circumferential centers of the plurality of protrusions do not overlap with the weight member and the protrusions. The centrifugal clutch means has a first region in the portion of at least one of the weight member and the pressure member where the weight member and the pressure member come into contact, and a second region in which the amount of axial movement of the output member of the pressure member per unit of radial movement of the weight member is smaller than that of the first region. When the weight member is in the inner diameter position, the weight member and the pressure contact member come into contact in the first region. A power transmission device in which the weight member and the pressure contact member come into contact in the second region when the weight member is in the outer diameter position.

2. The main body portion is formed between adjacent protrusions and has a plane on which the projections are located radially outward. The power transmission device according to claim 1, wherein, when viewed in the axial direction of the output member, the circumferential length of the radially outer portion of the plane is longer than the circumferential length of the radially inner portion of the plane.

3. The power transmission device according to claim 2, wherein the circumferential length of the plane gradually increases from the radially inner side to the radially outer side.

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