JP4859866B2 - Telescopic mechanism - Google Patents

Description

  The present invention relates to an expansion / contraction mechanism that converts rotational force into direct power to expand and contract.

As an expansion / contraction mechanism, an actuator is known in which power is transmitted from a rotation output shaft through a coupling, and rotational force is converted into direct power.
This type of telescopic mechanism includes a motor as a drive source, a speed reducer that decelerates the rotational speed of the motor, and a feed screw (screw portion) that transmits the rotational force of the motor decelerated by the speed reducer via a coupling. ) And a nut portion that meshes with the feed screw and converts the rotational force into direct power.

As such an expansion / contraction mechanism (actuator), one used for an independent rear wheel steering device is known (for example, see Patent Document 1).
JP 2007-290417 A

In the telescopic mechanism of Patent Document 1, the rotational force of a servo motor (motor) is transmitted to an inner cylinder formed with a screw part, and is transmitted to an outer cylinder formed with a nut part engaged with a male screw. Was converted into the direct power of the outer cylinder and expanded and contracted.
Furthermore, the independent rear-wheel steering apparatus was comprised by connecting the tie rod which changes the toe angle of a rear-wheel to the front-end | tip of the outer cylinder of said expansion-contraction mechanism.

  Such an expansion / contraction mechanism (actuator) generally includes a motor as a drive source, a speed reducer that decelerates the rotation speed of the motor, and a rotational force of the motor decelerated by the speed reducer via a coupling. A feed screw to be transmitted, a nut portion that meshes with the feed screw and converts rotational force into direct power, and a split housing that houses these motor, reducer, coupling, feed screw and nut portion The motor, the speed reducer, the coupling, the feed screw, and the nut portion are housed in a housing that is divided into two parts, and the housings are coupled to each other.

However, in such an expansion / contraction mechanism, an assembly error accumulates between a part housed in the one housing and a part housed in the other housing, thereby improving the assembly accuracy of each part. It was difficult.
That is, in the expansion / contraction mechanism described above, it has been desired to improve the assembly accuracy of each part and suppress the variation in quality.

  This invention makes it a subject to provide the expansion-contraction mechanism which can aim at the improvement of quality while improving the assembly | attachment precision of each component.

The invention according to claim 1 is a motor as a drive source, a speed reducer that decelerates the rotational speed of the motor, a feed screw that transmits the rotational force of the motor decelerated by the speed reducer via a coupling, A nut portion that meshes with the feed screw and converts rotational force into direct power, and housings the motor, speed reducer, coupling, feed screw and nut portion, and one side and the other side housing divided into two parts The one side housing is attached to the vehicle body, the other side housing is fixed to the rear wheel side, the motor and the speed reducer are stored exclusively in the one side housing, and the speed reducer is connected to the motor. A sun gear fitted to the output shaft, a ring gear arranged coaxially with the sun gear, and a plurality of planetary gears meshed with the sun gear and the ring gear. , Motor, whereas housed in side housing, characterized in that it is held on one side housing ring gear.

The invention according to claim 2 is characterized in that the outer peripheral portion of the ring gear and the outer peripheral surface of the motor case are held on the same inner peripheral surface of the one-side housing.

The invention according to claim 3 is characterized in that the ring gear is screwed into the inner peripheral surface of the one-side housing.
The invention according to claim 4 is characterized in that a male screw is formed on the outer peripheral portion of the ring gear, a female screw is formed on the inner peripheral surface of the one-side housing, and the ring gear is screwed into the female screw portion of the one-side housing.

In the invention according to claim 1, the telescopic mechanism transmits the motor as a drive source, a speed reducer that decelerates the rotational speed of the motor, and the rotational force of the motor decelerated by the speed reducer via the coupling. A feed screw, a nut portion that meshes with the feed screw and converts rotational force into direct power, and one side configured to divide the motor, reducer, coupling, feed screw, and nut portion into two parts And the other housing.
The one side housing is attached to the vehicle body, the other side housing is fixed to the rear wheel side, and the motor and the speed reducer are exclusively stored in the one side housing. As compared with the case of housing in the motor, it is possible to improve the assembling accuracy of the speed reducer with respect to the output shaft of the motor. As a result, since the assembling accuracy is good, for example, there is little wear of gears and the like. Therefore, the durability of the reduction gear can be improved.

The speed reducer includes a sun gear fitted to the output shaft of the motor, a ring gear arranged coaxially with the sun gear, and a plurality of planetary gears meshed with the sun gear and the ring gear. Since it is housed in the one-side housing and held in the one-side housing by the ring gear, for example, a mounting screw for attaching the motor to the one-side housing is unnecessary, and the assemblability of the telescopic mechanism can be improved. .

In the invention according to claim 2 , since the outer peripheral portion of the ring gear and the outer peripheral surface of the motor case are held on the same inner peripheral surface of the one-side housing, the coaxial accuracy of the ring gear and the motor can be improved.

In the invention according to claim 3 , since the ring gear is screwed to the inner peripheral surface of the one-side housing, for example, compared to a case where a mounting hole or mounting flange for mounting the ring gear to the one-side housing is provided, a screw head, etc. Since there is no protruding portion, the ring gear can be stored compactly in the one-side housing.
In the invention according to claim 4, since the male screw is formed on the outer peripheral portion of the ring gear, the female screw is formed on the inner peripheral surface of the one-side housing, and the ring gear is screwed to the female screw portion of the one-side housing. The assembly error when the other housing is assembled does not affect the misalignment between the sun gear and the ring gear.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a principle view of an independent rear wheel steering device on which an expansion / contraction mechanism according to the present invention is mounted.
The independent rear wheel steering device 10 includes a rear wheel 12 provided at a lower rear side of the vehicle body 11 so that a toe angle can be adjusted, a suspension (suspension device) 13 that supports the rear wheel 12 in a swingable manner, a vehicle body 11 side and a rear wheel. An actuator (extraction / contraction mechanism) 30 is provided between the wheel 12 side and controls the toe angle of the rear wheel 12.

  The suspension 13 is, for example, a double wishbon type suspension device, and includes a lower arm 16 that swingably extends from below the vehicle body 11, and an upper arm 17 that swings and extends above the lower arm 16 and from the vehicle body 11. These arms 16, 17 are rotatably provided, knuckle 18 that supports the rear wheel 12, the upper end is supported by the vehicle body 11, the lower end is attached to the lower arm 16, and an impact applied to the vehicle body 11 from the rear wheel 12 is applied. It consists of a shock absorber unit 19 that softens.

One end of the actuator 30 is swingably supported on the vehicle body 11 side, and the other end is swingably attached to the knuckle 18. As will be described later, the torque is converted into direct power to convert the toe angle of the rear wheel 12. Is to control.
The operation principle of the independent rear wheel steering apparatus 10 will be described with reference to the next figure.

2 (a) to 2 (c) are operation explanatory views of the independent rear wheel steering device on which the telescopic mechanism according to the present invention is mounted.
In (a), the independent rear wheel steering device 10 in an initial state in which the rear wheel 12 is positioned in parallel to the center of the vehicle body is shown.

In (b), the rear wheel 12 can be driven inward of the vehicle body 11 by extending the actuator 30 as shown by the arrow a1, and can be controlled to a toe-in state.
In (c), by retracting the actuator 30 as indicated by an arrow a2, the rear wheel 12 can be driven to the outside of the vehicle body 11 and controlled to a toe-out state.
Hereinafter, details of the actuator 30 will be described.

FIG. 3 is a front sectional view of the telescopic mechanism according to the present invention, and FIG. 4 is an exploded perspective view of main components of the telescopic mechanism according to the present invention.
As shown in FIGS. 3 and 4, the actuator (extension mechanism) 30 is a member that converts rotational force into direct power, is divided into two parts, and is provided on one side housing (vehicle body side member) that is attached to the vehicle body 11 side. ) 31 and the other side housing (rear wheel side member) 32 that is divided into two parts and is attached to the rear wheel 12 side, and the inner peripheral surface 33 of the one side housing 31 as a drive source that generates rotational force. A motor 34, an output shaft (rotational output shaft) 35 of the motor 34, a speed reducer 36 that is configured in one housing 31 and decelerates the rotational speed of the motor 34, and a final stage of the speed reducer 36 (Rotary power output member) 75 is connected to the other side housing 32 through a coupling 37 and is connected to the feed screw 38 for converting from rotational force to direct power. And a nut portion 39 that is attached to the other housing 32 and converts from rotational force to direct power, one housing (vehicle body side member) 31, and the other housing (rear wheel member) 32. And a dust boot 42 that covers the space through a rotary seal member 41.

The dust boot 42 is made of elastomer as a material that is resistant to stepping stones and has excellent weather resistance.
Elastomer is a synthetic polymer material, especially a material having elasticity and flexibility like rubber at around room temperature.

  The feed screw 38 and the nut portion 39 are conversion members that convert a rotational force into a direct power. The nut portion 39 is locked to the other housing 32 by a set screw 47.

The one side housing 31 includes a vehicle body side connecting portion 48 connected to the vehicle body 11 side, and the motor 34 and the speed reducer 36 are provided in the one side housing 31.
The other housing 32 includes a rear wheel side connecting portion 49 connected to the rear wheel 12 side, and the other housing 32 is provided with a feed screw 38 and a nut portion 39.

  That is, the actuator 30 is aligned with the one side housing 31 provided with the motor 34 and the speed reducer 36 with the other side housing 32 provided with the feed screw 38 and the nut portion 39 via the coupling 37. The dust boots 42 are put between the one side housing 31 and the other side housing 32.

  The motor 34 includes a rotor 51, a stator 52 provided around the rotor 51, and a motor case 53 that covers the rotor 51 and the stator 52, and an output shaft 35 is provided at the center of the rotor 51.

The motor case 53 includes a block portion 54 that projects one end of the output shaft 35 toward the speed reducer 36, and a storage portion 55 that is attached to the block portion 54 and fixes the stator 52 and rotatably supports the rotor 51. .
Further, the motor case 53 is held on the one side housing 31 by a ring gear 62 which is a component of the speed reducer 36, with the outer peripheral surface 56 (end surface of the block portion 54) of the motor case 53 sandwiched between the one side housing 31.

  As shown in FIG. 4, the speed reducer 36 includes a sun gear 61 fitted to the output shaft 35 of the motor 34, a ring gear 62 disposed coaxially with the sun gear 61, and the sun gear 61 and the ring gear 62. The first gear assembly 64 meshes with the first gear assembly 64 and the second gear assembly 65 meshes with the first gear assembly 64.

  A female screw 66 is formed on the inner peripheral surface 33 of the one side housing 31, and a male screw 68 is formed on the outer peripheral portion 67 of the ring gear 62, and is screwed onto the inner peripheral surface 33 of the one side housing 31.

  The first gear assembly 64 includes a disk-shaped first base 71, a plurality of planetary gears 72 that are rotatably attached to the first base 71 and meshed with the sun gear 61 and the ring gear 62, And a pinion 73 provided at the center of one base 71 and on the opposing surfaces of the plurality of planetary gears 72.

  The second gear assembly 65 includes a disk-shaped second base 75 and a plurality of gears rotatably attached to the second base 75 and meshed with the pinion 73 of the first gear assembly 64. 76.

The second base portion 75 is a final stage of the speed reducer 36 and is a member corresponding to a rotational power output member. The second base portion 75 is provided concentrically with the second base portion 75 and on the opposing surfaces of the plurality of gears 76. A plurality of protrusions 77 that engage with the ring 37 and a support shaft 78 that rotatably supports the plurality of gears 76 are provided.
In the figure, 79 is an oil seal interposed between the one side housing 31 and the other side housing 32.

FIG. 5 is a perspective view of the threaded portion and coupling of the telescopic mechanism according to the present invention, and FIG. 6 is a perspective view of the components of the coupling and speed reducer of the telescopic mechanism according to the present invention.
As shown in FIG. 5, the feed screw 38 includes a screw portion 81 that is screwed into the nut portion 39, a cup portion 82 that houses the coupling 37 on the coupling 37 side of the screw portion 81, A bottom portion 83 that is in sliding contact with the cylindrical portion 91 and a plurality of claw portions 84 that mesh with the coupling 37 are provided.

  As shown in FIGS. 5 and 6, the coupling 37 is a member in which three members of one side member 87, an intermediate member 88, and the other side member 89 are laminated. It extends radially from the cylindrical portion 91 and is interposed between the plurality of claw portions 84 of the feed screw 38 and the plurality of protrusions 77 of the speed reducer 36, and the shaft center on the feed screw 38 side and the shaft center on the motor 34 side. The engaging piece 92 transmits the rotational force on the motor 34 side to the feed screw 38 side while absorbing the deviation.

FIGS. 7 (a) and 7 (b) are comparative studies of the attachment state of the ring gear, which is a component of the speed reducer of the telescopic mechanism according to the present invention.
In (a), the attachment state of the ring gear 62 of the expansion-contraction mechanism 30 of an Example is shown, and the attachment state of the ring gear 234 of the expansion-contraction mechanism 230 of a comparative example is shown in (b).

In the telescopic mechanism 30, the ring gear 62 has a male screw 68 formed on the outer peripheral portion 67, a female screw 66 formed on the inner peripheral surface 33 of the one side housing 31, and the ring gear 62 has an inner peripheral surface 33 ( Screwed into the female thread portion 66). A motor 34 is attached to the one-side housing 31, and a sun gear 61 is attached to an output shaft 35 of the motor 34. Therefore, an assembly error when the other housing 32 is assembled to the one housing 31 does not affect the axial misalignment between the sun gear 61 and the ring gear 62.
The motor 34 is housed in the one-side housing 31 and is held by the stepped portion 98 of the one-side housing 31 by the ring gear 62.

  In the expansion / contraction mechanism 230, the ring gear 234 is press-fitted and formed on the inner peripheral surface 233 of the other housing 232. A motor 235 is attached to the one side housing 231 facing the other side housing 232, and a sun gear 237 is attached to the output shaft 236 of the motor 235.

Therefore, an assembling error when assembling the other housing 232 to the one housing 231 appears as an axial misalignment between the sun gear 237 and the ring gear 234. Therefore, the coaxial accuracy between the ring gear 234 and the sun gear 237 (motor 235) is not good.
Further, the motor 235 is held on the one-side housing 231 by a mounting screw 238.

  The telescopic mechanism 30 includes a motor 34 as a drive source, a speed reducer 36 that decelerates the rotational speed of the motor 34, and a feed that transmits the rotational force of the motor 34 decelerated by the speed reducer 36 via a coupling 37. The screw 38, a nut portion 39 that is meshed with the feed screw 38 and converts the rotational force into direct power, and the motor 34, the speed reducer 36, the coupling 37, the feed screw 38, and the nut portion 39 are accommodated. It is comprised from the one side and the other side housings 31 and 32 comprised by 2 divisions.

  Since the motor 34 and the speed reducer 36 are exclusively stored in the one-side housing 31, for example, compared with a case where some parts of the speed reducer 36 are stored in another housing, the speed reducer for the output shaft 35 of the motor 34. The assembly accuracy of 36 can be improved. As a result, since the assembling accuracy is good, for example, there is little wear of gears and the like. Therefore, the durability of the speed reducer 36 can be improved.

  The reduction gear 36 includes a sun gear 61 fitted to the output shaft 35 of the motor 34, a ring gear 62 disposed coaxially with the sun gear 61, and a plurality of planetary gears 72 meshed with the sun gear 61 and the ring gear 62. Since the motor 34 is housed in the one-side housing 31 and is held by the one-side housing 31 by the ring gear 62, for example, a mounting screw for attaching the motor 34 to the one-side housing 31 is unnecessary. Thus, it is possible to improve the assembling property of the telescopic mechanism 30.

  Further, since the outer peripheral portion 67 of the ring gear 62 and the outer peripheral surface 56 of the motor case 53 are held on the same inner peripheral surface 33 of the one-side housing 31, the coaxial accuracy of the ring gear 62 and the motor 34 can be improved. it can.

  Further, since the ring gear 62 is screwed into the inner peripheral surface 33 of the one-side housing 31, for example, compared with a case where a mounting hole or a mounting flange for mounting the ring gear 62 to the one-side housing 31 is provided, a screw head or the like. Since there is no protruding portion, the ring gear 62 can be stored in the one-side housing 31 in a compact manner.

    As shown in FIG. 7, the telescopic mechanism 30 according to the present invention is configured to receive the motor 34 at the stepped portion 98 of the one-side housing 31. However, the present invention is not limited to this, and the inner peripheral surface of the one-side housing. A part of the motor may be adapted to receive a motor.

  The telescopic mechanism according to the present invention is suitable for use in passenger cars such as sedans and wagons.

It is a principle figure of the independent rear-wheel steering device by which the expansion-contraction mechanism based on this invention is mounted. It is operation | movement explanatory drawing of the independent rear-wheel steering apparatus by which the expansion-contraction mechanism based on this invention is mounted. It is front sectional drawing of the expansion-contraction mechanism which concerns on this invention. It is a disassembled perspective view of the main components of the expansion-contraction mechanism concerning this invention. It is a perspective view of the thread part and coupling of the expansion-contraction mechanism concerning this invention. It is a perspective view of the component of the coupling of the expansion-contraction mechanism which concerns on this invention, and a reduction gear. It is a comparative examination figure of the attachment state of the ring gear which is a component of the reduction gear of the expansion-contraction mechanism which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 30 ... Telescopic mechanism (actuator), 31 ... One side housing, 32 ... Other side housing, 33 ... Inner peripheral surface, 34 ... Motor, 35 ... Output shaft, 36 ... Reduction gear, 37 ... Coupling, 38 ... Lead screw, 39 ... nut portion, 53 ... motor case, 56 ... outer peripheral surface, 61 ... sun gear, 62 ... ring gear, 72 ... planetary gear.

Claims (4)

A motor as a drive source, a speed reducer that reduces the rotational speed of the motor, a feed screw that transmits the rotational force of the motor decelerated by the speed reducer via a coupling, and meshed with the feed screw, In a telescopic mechanism comprising a nut portion that converts rotational force into direct power, and a motor housing a reduction gear, a coupling, a feed screw, and a nut portion, and one side and the other side housing that are divided into two parts.
The one side housing is attached to the vehicle body, the other side housing is fixed to the rear wheel side, and the motor and the speed reducer are exclusively stored in the one side housing ,
The speed reducer includes a sun gear fitted to the output shaft of the motor, a ring gear arranged coaxially with the sun gear, and a plurality of planetary gears meshed with the sun gear and the ring gear,
The expansion / contraction mechanism is characterized in that the motor is housed in one side housing and held by the one side housing by the ring gear . Wherein the outer peripheral portion and the outer peripheral surface of the motor case of the ring gear, telescopic mechanism according to claim 1, characterized in that it is held in the same inner peripheral surface of the one side housing. The telescopic mechanism according to claim 2 , wherein the ring gear is screwed into an inner peripheral surface of the one-side housing. The male screw is formed in the outer peripheral part of the said ring gear, the female screw is formed in the internal peripheral surface of the said one side housing, The said ring gear was screwed together in the female thread part of the said one side housing, The 1-3 characterized by the above-mentioned. The expansion-contraction mechanism of any one of these.

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