Gear reducer and gearmotor

A gear reducer has a helical gear, an eccentric shaft that is joined to the helical gear and has a first supporting portion that is offset in a rotation radial direction with respect to a rotation shaft of the helical gear, and a slider plate that is disposed at a radial direction outer side of the eccentric shaft. Further, the gear reducer has a transmitting gear that is supported at a first supporting portion, and whose rotation around its own axis is restricted due to the transmitting gear being engaged with the slider plate, and that revolves due to the helical gear rotating together with the eccentric shaft, and has an output gear body that rotates due to the transmitting gear revolving. The transmitting gear has a pair of restricting projections that project-out toward the slider plate side, and the slider plate is disposed between the pair of restricting projections.

TECHNICAL FIELD

Present aspects relate to a gear reducer and a gearmotor.

BACKGROUND ART

A gearmotor having a gear reducer that decelerates the rotation of a motor is disclosed in Chinese Patent Application Publication No. 104638830. The gear reducer disclosed in that document has a worm that is fixed to the rotation shaft of the motor, a worm wheel that meshes with the worm, a gear that, due to the worm wheel rotating, revolves in a state in which rotation around its own axis is restricted, and an output shaft that rotates due to the rotation force, which accompanies the revolving of the revolving gear, being transmitted thereto. Further, a member that restricts rotation of the revolving gear around its own axis is provided between the worm wheel and the revolving gear.

SUMMARY

Technical Problem

By the way, the gear reducer of the gearmotor that is disclosed in Chinese Patent Application Publication No. 104638830 is structured such that the rotation of the revolving gear around its own axis is restricted due to a portion of the revolving gear engaging with the inner peripheral surface of the member that restricts the rotation of the revolving gear around its own axis. Therefore, it is difficult to devise downsizing of the build, in the radial direction, of the member that restricts the rotation of the revolving gear around its own axis, and downsizing of the builds of the gear reducer and a motor that has this gear reducer is hindered.

In view of the above-described circumstances, an object is to provide a gear reducer and a gearmotor at which downsizing of the builds thereof can be devised.

Solution to Problem

In order to solve the above-described problem, a gear reducer relating to a present aspect comprises: a first gear that rotates due to rotational force being transmitted thereto; an eccentric shaft that is joined to the first gear, and that has a supporting portion that is offset in a rotation radial direction with respect to a rotation shaft of the first gear; an own-axis-rotation restricting member that is disposed at a radial direction outer side of the eccentric shaft; a transmitting gear that is supported at the supporting portion, and whose rotation around its own axis is restricted due to the transmitting gear being engaged with the own-axis-rotation restricting member, and that revolves around the rotation shaft of the first gear due to the first gear rotating together with the eccentric shaft; and an output portion that rotates due to the transmitting gear revolving, wherein the transmitting gear has a pair of restricting projections that project-out toward the own-axis-rotation restricting member side, and the own-axis-rotation restricting member is disposed between the pair of restricting projections.

In order to solve the above-described problem, a gearmotor relating to a present aspect comprises: a motor that has a rotation shaft; a first gear that rotates due to rotational force of the rotation shaft being transmitted thereto; an eccentric shaft that is joined to the first gear, and that has a supporting portion that is offset in a rotation radial direction with respect to a rotation shaft of the first gear; an own-axis-rotation restricting member that is disposed at a radial direction outer side of the eccentric shaft; a transmitting gear that is supported at the supporting portion, and whose rotation around its own axis is restricted due to the transmitting gear being engaged with the own-axis-rotation restricting member, and that revolves around the rotation shaft of the first gear due to the first gear rotating together with the eccentric shaft; and an output portion that rotates due to the transmitting gear revolving, wherein the transmitting gear has a pair of restricting projections that project-out toward the own-axis-rotation restricting member side, and the own-axis-rotation restricting member is disposed between the pair of restricting projections.

Advantageous Effects of Invention

The above-described gear reducer and gearmotor have the excellent effect that downsizing of the builds thereof can be devised.

DESCRIPTION OF EMBODIMENTS

A gearmotor10relating to an embodiment of the present aspect is described by usingFIG. 1throughFIG. 4. Note that the arrow Z direction, the arrow R direction and the arrow C direction that are shown appropriately in the drawings indicate a rotation axial direction one side, a rotation radial direction outer side and a rotation peripheral direction one side of a pinion gear30C that is the output gear, respectively. Further, the side opposite the arrow Z direction, the side opposite the arrow R direction and the side opposite the arrow C direction indicate a rotation axial direction another side, a rotation radial direction inner side, and a rotation peripheral direction another side of the pinion gear30C that is the output gear, respectively. Moreover, when simply axial direction radial direction and peripheral direction are used, they refer to the rotation axial direction, the rotation radial direction, and the rotation peripheral direction of the pinion gear30C, unless otherwise indicated.

As shown inFIG. 1,FIG. 2andFIG. 3, the gearmotor10of the present embodiment is a motor for a power seat that is for moving a seat cushion of a vehicle seat in the seat vertical direction. This gearmotor10has a motor12that is a DC motor. Further, the gearmotor10has a gear reducer14that is for decelerating the rotation of a rotation shaft12A of the motor12, and transmitting the decelerated rotational force to an output gear body30that serves as the output portion. Moreover, the gearmotor10has a housing16to which the motor12is mounted and at whose interior the gear reducer14is provided.

The gear reducer14has a worm gear18that is fixed to the rotation shaft12A of the motor12, a helical gear20that serves as the first gear and meshes with the worm gear18, and an eccentric shaft22that is provided integrally with the helical gear20.

Further, the gear reducer14has a transmitting gear24and a lock gear26that are supported at the eccentric shaft22, and a fixed gear28that meshes with the lock gear26. Moreover, the gear reducer14has a slider plate52that serves as the own-axis-rotation restricting member, and that is supported at the fixed gear28, and that, by being engaged with the transmitting gear24, restricts rotation of the transmitting gear24around its own axis. Further, the gear reducer14has the output gear body30that meshes with the transmitting gear24, and that has the pinion gear30C, and whose axial direction faces in the same direction as the axial directions of the helical gear20, the transmitting gear24and the lock gear26(faces in the arrow Z direction and the direction opposite to the arrow Z direction), and that is disposed coaxially with the helical gear20.

Further, the gearmotor10has a spring32for suppressing rattling of the eccentric shaft22, the helical gear20and the like in the axial direction. Further, the gearmotor10has a cover plate34that, due to the cover plate34being fixed to the housing16, the gear reducer14is accommodated within the housing16.

As shown inFIG. 1andFIG. 2, the housing16is formed by using a resin material. This housing16has a motor fixing portion16A that is fixed in a state in which the rotation shaft12A of the motor12faces in a direction orthogonal to the axial direction (the arrow Z direction). Further, the housing16has a gear reducer accommodating concave portion16C in which the gear reducer14is accommodated. This gear reducer accommodating concave portion16C is formed in a concave shape whose axial direction one side (arrow Z direction side) is open.

As shown inFIG. 1, the gear reducer accommodating concave portion16C is structured to include a bottom wall portion that forms the bottom of the gear reducer accommodating concave portion16C, and a side wall portion16E that extends toward the axial direction one side from the outer peripheral portion of the bottom wall portion and whose inner peripheral surface is formed substantially in the shape of a cylindrical tubular surface. A boss portion, which is cylindrical tube shaped and in which the axial direction another side end portion of a rotation central shaft40that is described later is inserted with clearance, stands upright at the central portion of the bottom wall portion of the gear reducer accommodating concave portion16C. Further, the spring32is disposed around the boss portion at the bottom wall portion. Note that a washer36is interposed between the bottom wall portion and the spring32.

Three fixed gear engaging portions16G, which restrict rotational displacement of the fixed gear28that is described later in the peripheral direction due to portions of the fixed gear28being fit-together therewith, are formed at the inner peripheral portion of the side wall portion16E of the gear reducer accommodating concave portion16C. Pillar portions16I that are shaped as cylindrical pillars are provided at the three fixed gear engaging portions16G.

The cover plate34is formed by using a steel plate member or the like. An exposure opening34A, which is for exposing the pinion gear30C to the outer side of the gear reducer accommodating concave portion16C of the housing16, is formed in this cover plate34. Further, a rib34B, which is annular and is bent toward the axial direction another side, is formed at the peripheral edge portion of the exposure opening34A at the cover plate34.

A spiral tooth portion is formed at the outer peripheral portion of the worm gear18. Due to the motor12, which is in a state in which the worm gear18is fixed to the rotation shaft12A, being fixed to the housing16, the worm gear18is disposed at the bottom wall portion side of the gear reducer accommodating concave portion16C and at the inner peripheral surface side of the side wall portion16E of the housing16.

As shown inFIG. 1andFIG. 2, the helical gear20is formed by using a resin material. Plural outer teeth which mesh with the tooth portion of the worm gear18are formed at the outer peripheral portion of the helical gear20. The eccentric shaft22that is described later is fixed to the axially central portion of the helical gear20by insert molding. Further, the helical gear20is rotatably supported at the housing16via the eccentric shaft22and the rotation central shaft40.

As shown inFIG. 2andFIG. 3, the eccentric shaft22is formed by using a metal material, and can rotate integrally with the helical gear20due to a portion thereof being inserted in the helical gear20. Concretely, the eccentric shaft22has a disc portion22A that is formed in the shape of a disc and extends in the radial direction with the axial direction being the thickness direction thereof. The outer peripheral portion of this disc portion22A is formed in a recessed and protruded form along the peripheral direction. Further, the disc portion22A is fixed to the inner peripheral portion of the helical gear20in a state in which the axial center of the disc portion22A and the rotational center of the helical gear20coincide.

Further, as shown inFIG. 1andFIG. 3, the eccentric shaft22has a supporting portion22B that projects-out toward the axial direction one side from the central portion of the disc portion22A. The axial direction one side of the supporting portion22B is a first supporting portion22B1at which the transmitting gear24, which is described later, is rotatably supported. Further, the axial direction another side of the supporting portion22B is a second supporting portion22B2that is set to a larger diameter than the first supporting portion22B1and at which the lock gear26, which is described later, is rotatably supported. The axial centers of the first supporting portion22B1and the second supporting portion22B2are offset, toward one radial direction outer side direction, with respect to the axial center of the disc portion22A.

Further, as shown inFIG. 2,FIG. 3andFIG. 4, a rotation central shaft insert-through hole22C, through which the disc portion22A, the first supporting portion22B1and the second supporting portion22B2pass in the axial direction and into which the rotation central shaft40is inserted, is formed in the eccentric shaft22. The axial center of this rotation central shaft insert-through hole22C (the axial center of the rotation central shaft40that is inserted-through the rotation central shaft insert-through hole22C) coincides with the axial center of the disc portion22A.

As shown inFIG. 2andFIG. 4, the output gear body30is formed by using a metal material. This output gear body30has a transmitting gear engaging portion30B that engages with the transmitting gear24. As shown inFIG. 2, an accommodating concave portion30E, which opens toward the transmitting gear24side (the axial direction another side) and at whose interior a transmitting gear main body portion24D of the transmitting gear24is disposed, is formed in the transmitting gear engaging portion30B. Plural inner teeth30F that mesh with outer teeth24A of the transmitting gear24are formed at the inner peripheral portion of the radial direction outer side of this accommodating concave portion30E.

Further, the output gear body30has the pinion gear30C that is disposed coaxially with the transmitting gear engaging portion30B at the axial direction one side of the transmitting gear engaging portion30B, and at whose outer peripheral portion plural outer teeth are formed. Further, the intermediate portion, between the transmitting gear engaging portion30B and the pinion gear30C, at the output gear body30is a pivotally-supported portion30D that is pivotally supported by the rib34B that is formed at the cover plate34. Note that a shaft-receiving bush42that is formed by using a resin material or the like is engaged with the inner peripheral surface of the rib34B. Due thereto, contact between the metals of the pivotally-supported portion30D of the output gear body30and the rib34B of the cover plate34is prevented or suppressed. Further, the rotation central shaft40, which is formed in the shape of a rod by using a metal material, is fixed to the axially central portion of the output gear body30by press-fitting or the like.

As shown inFIG. 1andFIG. 2, the fixed gear28is formed by press working or the like being carried out on a metal material. This fixed gear28has a fixed gear main body portion28A that is formed in an annular shape as seen in the axial direction. Further, the fixed gear28has three engaging projections28B that project-out from the fixed gear main body portion28A toward the radial direction outer side. Further, the fixed gear28is fixed to the housing16due to unillustrated bush nuts being engaged with the pillar portions16I in the state in which the engaging projections28B are engaged with the fixed gear engaging portions16G of the housing16.

Plural inner teeth28D, with which the lock gear26that is described later mesh, are formed at the inner peripheral portion of the fixed gear main body portion28A.

Moreover, the fixed gear28has a second restricting portion28E that projects-out toward the axial direction another side from the fixed gear main body portion28A. This second restricting portion28E projects-out from a peripheral direction portion of the fixed gear main body portion28A toward the axial direction another side.

Further, a slider plate engaging hole28F, whose edge portion is formed in a rectangular shape (an oblong shape) as seen in the axial direction and at whose interior the slider plate52is disposed, is formed in the axially central portion at the axial direction one side of the portion, at which the inner teeth28D are formed, of the fixed gear main body portion28A of the fixed gear28. Further, at the edge portion of the slider plate engaging hole28F, the surfaces, which are disposed so as to face a pair of first slider surfaces52C of the slider plate52that is described later in the radial direction respectively, are second slider surfaces28G. Further, rotation of the slider plate52with respect to the fixed gear28is restricted due to the first slider surfaces52C and the second slider surfaces28G being disposed so as to face one another and be close to one another. Further, due to the first slider surfaces52C sliding on the second slider surfaces28G, displacement of the slider plate52and the transmitting gear24in one direction R1that is a radial direction is permitted. Due thereto, at the time when the eccentric shaft22rotates, the transmitting gear24revolves around the axial center of the rotation central shaft40in a state in which the rotation of the transmitting gear24, which is supported at the first supporting portion22B1of the eccentric shaft22, around its own axis is restricted.

As shown inFIG. 1,FIG. 2,FIG. 3andFIG. 4, the transmitting gear24is formed substantially in the shape of a disc by press working or the like being carried out on a metal material. This transmitting gear24has the transmitting gear main body portion24D at whose outer peripheral portion the plural outer teeth24A are formed. A supporting hole24B, which is supported at the first supporting portion22B1of the eccentric shaft22, is formed in the central portion of the transmitting gear main body portion24D. Further, the transmitting gear24has two restricting projections24E that project-out toward the axial direction another side from the axial direction another side surface of the transmitting gear main body portion24D. These two restricting projections24E are disposed at a uniform interval (a pitch of 180 degrees) along the peripheral direction. Further, due to the two restricting projections24E engaging with the slider plate52that is described later, rotation (own-axis-rotation) of the transmitting gear24around the first supporting portion22B1of the eccentric shaft22is restricted.

As shown inFIG. 1andFIG. 3, the slider plate52is formed by using a plate member that is made of metal, and is formed in a rectangular shape (an oblong shape) as seen in the axial direction. This slider plate52is disposed between the two restricting projections24E of the transmitting gear24, at the interior of the slider plate engaging hole28F that is formed in the fixed gear28. Further, the surfaces, which are disposed so as to face the two restricting projections24E in the radial direction respectively, at the outer peripheral portion of the slider plate52are engaged surfaces52B. Further, in the state in which the slider plate52is disposed between the two restricting projections24E of the transmitting gear24, displacement of the transmitting gear24with respect to the slider plate52in the direction in which the engaged surfaces52B and the restricting projections24E face one another (the one direction R1that is a radial direction) is restricted, and rotation (own-axis-rotation) of the transmitting gear24with respect to the slider plate52is restricted. Further, due to the restricting projections24E sliding on the engaged surfaces52B, displacement of the transmitting gear24with respect to the slider plate52in the direction in which the engaged surfaces52B and the restricting projections24E slide (another direction R2that is a radial direction that is orthogonal to the one direction R1that is a radial direction) is permitted. Further, the pair of surfaces, which are disposed so as to face and be near to the second slider surfaces28G of the slider plate engaging hole28F, at the outer peripheral portion of the slider plate52are the first slider surfaces52C. Note that an insert-through hole52A, which is shaped as a long hole (shaped as a long hole whose length direction is the another direction R2that is a radial direction) and through which the first supporting portion22B1of the eccentric shaft22is inserted, is formed in the axially central portion of the slider plate52. Further, in the present embodiment, the interval between the pair of engaged surfaces52B of the slider plate52is set to a dimension that is smaller than the interval between the pair of first slider surfaces52C. Due thereto, as seen in the axial direction, the slider plate52is a rectangular shape at which the pair of engaged surfaces52B are the long sides and the pair of first slider surfaces52C are the short sides.

As shown inFIG. 1andFIG. 2, in the same way as the transmitting gear24, the lock gear26is formed in a disc-shape due to press working or the like being carried out on a metal material. Outer teeth26A, which mesh with the inner teeth28D of the fixed gear28, are formed at the outer peripheral portion of the lock gear26over the entire periphery thereof. A supporting hole26B, which is supported at the second supporting portion22B2of the eccentric shaft22, is formed in the central portion of the lock gear26. Moreover, the lock gear26has a first restricting portion26C that projects-out toward the radial direction outer side and that is formed in a fan shape as seen from the axial direction. This first restricting portion26C is provided at a peripheral direction portion of the lock gear26. Further, in the state in which outer teeth26A of the lock gear26are meshed with the inner teeth28D of the fixed gear28, the first restricting portion26C is disposed along the axial direction another side surface of the fixed gear main body portion28A of the fixed gear28.

Operation and Effects of Present Embodiment

Operation and effects of the present embodiment are described next.

As shown inFIG. 1andFIG. 2, in accordance with the gearmotor10of the present embodiment, when the rotation shaft12A of the motor12rotates, the worm gear18rotates. Further, when the worm gear18rotates, the helical gear20that is meshed with the worm gear18rotates together with the eccentric shaft22.

Moreover, when the eccentric shaft22rotates, the transmitting gear24that is supported at the first supporting portion22B1of the eccentric shaft22revolves around the rotation central shaft40. In more detail, as shown inFIG. 5,FIG. 6andFIG. 7, when the eccentric shaft22rotates, the restricting projections24E of the transmitting gear24move in the radial direction (arrow R2and the direction opposite R2) while sliding on the engaged surfaces52B of the slider plate52. Further, the slider plate52and the transmitting gear24move in the radial direction (arrow R1and the direction opposite R1) while the first slider surfaces52C of the slider plate52slide on the second slider surfaces28G of the fixed gear28. Due thereto, the transmitting gear24revolves around the axial center of the rotation central shaft40, in the state in which the own-axis-rotation of the transmitting gear24, which is supported by the first supporting portion22B1of the eccentric shaft22, is restricted. Note that dimension D that is shown inFIG. 6andFIG. 7is the amount of offset of the axial center of the first supporting portion22B1with respect to the axial center of the disc portion22A.

As shown inFIG. 1andFIG. 2, when the transmitting gear24revolves, the rotational force that accompanies this revolution is transmitted to the output gear body30from the outer teeth24A of the transmitting gear24via the inner teeth30F of the output gear body30. Due thereto, the output gear body30rotates, and the power seat of the vehicle can be operated via a gear that meshes with the pinion gear30C of the output gear body30.

Further, when the eccentric shaft22rotates, the lock gear26, which is supported by the second supporting portion22B2of the eccentric shaft22, rotates around its own axis and revolves around the rotation central shaft40while remaining meshed with the fixed gear28. Then, when the first restricting portion26C of the lock gear26abuts the second restricting portion28E of the fixed gear28, revolution and rotation around its own axis of the lock gear26are restrained. Due thereto, rotation of the eccentric shaft22and the helical gear20are stopped, and rotation of the output gear body30is stopped (rotation is restricted). As a result, an excessive force being inputted from the gearmotor10to the vehicle seat is prevented or suppressed, and a deterioration in the seating comfort, which is due to members that structure the vehicle seat deforming or the like, can be prevented or suppressed.

Further, in the present embodiment, both the lock gear26, which is for restricting the amount of rotation of the output gear body30, and the slider plate52, which is for restricting the rotation of the transmitting gear24around its own axis, are structures that mesh with or engage with the single fixed gear28. Due thereto, as compared with a case in which the lock gear26and the slider plate52are structures that mesh with respectively different fixed gears, downsizing of the builds, in the axial direction, of the gear reducer14and the gearmotor10that is structured to include this gear reducer14can be devised. Further, in the present embodiment, the transmitting gear24and the slider plate52are disposed in a state of being adjacent to and contacting one another in the axial direction. Due thereto, even further downsizing of the builds, in the axial direction, of the gear reducer14and the gearmotor10that is structured to include this gear reducer14can be devised.

Further, in the present embodiment, the slider plate52, which restricts rotation of the transmitting gear24around its own axis, is disposed between the two restricting projections24E of the transmitting gear24. Due thereto, as compared with a structure in which the two restricting projections24E of the transmitting gear24engage with the inner peripheral portion of the slider plate52, an increase in the radial direction dimension of the slider plate52can be suppressed. Due thereto, downsizing of the builds, in the radial direction, of the gear reducer14and the gearmotor10that is structured to include this gear reducer14can be devised.

Further, in the present embodiment, by setting the interval between the pair of engaged surfaces52B of the slider plate52to be a dimension that is smaller than the interval between the pair of first slider surfaces52C, the slider plate52is, as seen in the axial direction, a rectangular shape at which the pair of engaged surfaces52B are the long sides. Due thereto, the interval between the two restricting projections24E of the transmitting gear24increasing can be suppressed, and an increase in the diameter of the transmitting gear24can be suppressed. As a result, even further downsizing of the builds, in the radial direction, of the gear reducer14and the gearmotor10that is structured to include this gear reducer14can be devised.

Note that the present embodiment describes an example in which the interval between the pair of engaged surfaces52B of the slider plate52is set to be a dimension that is smaller than the interval between the pair of first slider surfaces52C, but the present invention is not limited to this. It suffices to establish whether or not the interval between the pair of engaged surfaces52B of the slider plate52is set to be a dimension that is smaller than the interval between the pair of first slider surfaces52C, appropriately in consideration of the reduction ratio of the gear reducer14, the outer diameter of the transmitting gear24, and the like.

Further, although the present embodiment describes an example in which the lock gear26that stops the rotation of the output gear body30is provided, the present invention is not limited to this. It suffices to select whether or not the lock gear26is to be provided, appropriately in consideration of the rigidities of the seat cushion frame and the links that structure portions of the vehicle seat.

Further, the gear reducer14, which structures a portion of the above-described gearmotor10, is a gear reducer to which a so-called planetary gear mechanism is applied. Therefore, it suffices to select the gear whose rotation is limited, appropriately in consideration of the reduction ratio that is required of the gear reducer14, and the like. Namely, it suffices to select which structure among a planetary type such as a 2K-H planetary gear mechanism, a 3K planetary gear mechanism or the like, a solar type, or a star type is to be employed, appropriately in consideration of the reduction ratio that is required of the gear reducer14, and the like.

Although an embodiment of the present invention has been described above, present aspects are not limited to the above, and can, of course, be implemented by being modified in various ways other than the above within a scope that does not depart from the gist thereof