Patent Application
20180361885
The present invention is related to a motion conversion apparatus for a vehicle.
As a motion conversion apparatus for a vehicle, an electrically-operated lumbar support apparatus described in Patent document 1 is conventionally known, for example. The apparatus is provided with a panel including an arch shape and provided at a seatback. The apparatus changes a distance between both end portions of the panel in an up and down direction to change the arch shape, and thus performs lumber support adjustment.
At the apparatus of Patent document 1, an end portion of the panel is fixedly attached to one end portion of a cable and the other end portion of the cable is fixedly attached to a rack of a gear box. The rack engages with a pinion of the gear box. When the pinion is rotated, the rotary motion is converted into a linear motion of the rack and the linear motion is transmitted to the end portion of the panel via the cable, and thus the arch shape of the panel is changed.
Patent document 1: Japanese National Phase Laid-Open Patent Publication No. 2004-525736
In Patent document 1, a space needed for the movement of the rack, wherein the rack performs the linear motion in association with the rotary motion of the pinion, is twice or more of a movement amount (stroke) of the rack. This is because as an engagement position with the pinion comes closer to one end portion of the rack, the engagement position becomes away from the other end portion of the rack. Accordingly, a motion conversion apparatus using a pinion and a rack unavoidably increases in size as a whole.
An objective of the present invention is to provide a motion conversion apparatus for a vehicle which can be more reduced in size as a whole.
A motion conversion apparatus for a vehicle which solves the above-described problem includes a fixed member including an internal gear arranged around a first axis, an input member configured to rotate about the first axis, a planetary gear including an external gear engaging with the internal gear, and an output portion, the planetary gear being supported by the input member to be rotatable about a second axis arranged eccentrically relative to the first axis. In association with rotation of the input member, the planetary gear is configured to revolve around the first axis along the internal gear while self-rotating about the second axis such that the output portion performs a linear motion.
An embodiment of a motion conversion apparatus for a vehicle will be explained hereunder.
As illustrated in
The seatback 3 includes a panel 5 built in the seatback 3. The panel 5 is formed in a substantially quadrangular plate shape and includes a surface facing a front and rear direction. The panel 5 is curved to include an arch shape protruding in a front direction. The panel 5 includes an upper end and a lower end. As a position of the lower end is changed in an up and down direction relative to the upper end, a distance between the upper end and the lower end is changed, and thus the arch shape of the panel 5 is changed. Accordingly, lumber support adjustment is performed such that a more favorable state for the occupant is obtained.
A seat drive apparatus 10 is built in a side portion at one side (the left side when facing the front direction of the seat 1) of the seatback 3. An output portion of the seat drive apparatus 10 is connected to a lower end of the panel 5 via a cable 30 which is a push-pull cable. The seat drive apparatus 10 causes the cable 30 to move back and forth, thereby pushing and pulling the lower end of the panel 5, and thus the seat drive apparatus 10 changes the arch shape of the panel 5.
As illustrated in
A motor 12 is fastened to the main body case 11 with plural screws 13. The motor 12 serving as an electric drive source is coaxial with the first accommodation portion 11a and is fixed to an opening end of the first accommodation portion 11a. A worm 14 including a substantially cylindrical shape is accommodated in the first accommodation portion 11a, and a rotary shaft 12a of the motor 12 is fixed to the worm 14 by press-fitting such that the rotary shaft 12a and the worm 14 rotate integrally with each other. A worm wheel 15 including a substantially cylindrical shape and engaging with the worm 14 is rotatably accommodated in the second accommodation portion 11b. The worm wheel 15 is provided with a fitting hole 15a which is coaxial with the bearing hole 11d and includes a substantially elongated circular shape penetrating a central portion of the worm wheel 15. A pinion 16 is connected to the worm wheel 15 such that the pinion 16 rotates coaxially and integrally with the worm wheel 15. The pinion 16 includes integrally therewith a fitting portion 16a, a shaft portion 16b and a gear portion 16c. The fitting portion 16a is fitted into the fitting hole 15a and includes a columnar shape of which a cross section is substantially elongated circular shape. The shaft portion 16b includes a substantially circular column shape and includes an outer diameter which is equivalent to the inner diameter of the bearing hole 11d. The shaft portion 16b is provided at the fitting portion 16a so as to protrude. The gear portion 16c is provided at the fitting portion 16a so as to protrude, at a side opposite to the shaft portion 16b. As the shaft portion 16b of the pinion 16 is inserted in the bearing hole 11d and is supported thereat, the worm wheel 15 is rotatable integrally with the pinion 16 inside the second accommodation portion 11b. The bottom portion of the third accommodation portion 11c is raised relative to the bottom portion of the second accommodation portion 11b by a dimension (by thickness) of the worm wheel 15 in an axial direction. Thus, the support shaft 11e and the gear portion 16c are arranged side by side in a radial direction thereof.
A gear 17 which includes a substantially cylindrical shape and serves as an input member engaging with the gear portion 16c is rotatably accommodated in the third accommodation portion 11c. The gear 17 is formed with a bearing hole 17a formed in a substantially circular shape. The bearing hole 17a includes an inner diameter which is equivalent to an outer diameter of the support shaft 11e and penetrates at a central portion of the gear 17. As the support shaft 11e is inserted in the bearing hole 17a, the gear 17 is rotatable inside the third accommodation portion 11c about a first axis O1. The gear 17 includes a step portion 17b protrudingly provided around the bearing hole 17a so as to be coaxial with the first axis O1. The step portion 17b includes a substantially annular shape. The gear 17 also includes a support shaft 17c protrudingly provided on the step portion 17b. The support shaft 17c is formed in a substantially circular column shape including an axis which is parallel to the first axis O1.
A ring gear 18 serving as a fixed member is fastened with plural screws 19 to an opening end of the main body case 11 (the second accommodation portion 11b, for example) in which, for example, the worm wheel 15 is accommodated. The ring gear 18 includes a lid portion 18a blocking or closing the second accommodation portion 11b. The ring gear 18 integrally includes an annular portion 18b opening the third accommodation portion 11c. An internal gear 18c is formed at an inner peripheral portion of the annular portion 18b over the entire periphery of the annular portion 18b. The internal gear 18c is arranged to be coaxial with the gear 17. At the annular portion 18b, a flange 18d is formed at an opening end which faces the gear 17. The flange 18d faces inward and includes an inner diameter which is equivalent to an outer diameter of the step portion 17b. As an outer peripheral surface of the step portion 17b is in contact with the inner peripheral surface of the flange 18d in a slidable manner, the annular portion 18b restricts an axial misalignment of the gear 17 from occurring. The support shaft 17c is positioned within a space portion surrounded by the internal gear 18c.
For example, when the motor 12 (the rotary shaft 12a) rotates in one direction, the rotation is decelerated and transmitted to the pinion 16 via the worm 14 and the worm wheel 15. The rotation of the pinion 16 is further decelerated between the gear 17 and is transmitted to the gear 17. Together with the worm 14, the worm wheel 15 and the pinion 16, the gear 17 forms a decelerator which decelerates the rotation of the motor 12.
A planetary gear 21 including a substantially cylindrical shape is supported at the support shaft 17. The planetary gear 21 is provided with a bearing hole 21a formed in a substantially circular shape and including an inner diameter which is equivalent to an outer diameter of the support shaft 17c. The support shaft 17c is rotatably inserted in the bearing hole 21a. The planetary gear 21 includes an external gear 21b formed along over the entire periphery of an outer peripheral portion of the planetary gear 21, and the external gear 21b engages with the internal gear 18c. Accordingly, the planetary gear 21 revolves about the first axis O1 along the internal gear 18c while self-rotating about a second axis O2 (the support shaft 17c) which is eccentric relative to the first axis O1. A diameter D2 of a pitch circle of the external gear 21b is set to be one half, that is, ½ of a diameter D1 of a pitch circle of the internal gear 18c. The planetary gear 21 includes plural (four in the present embodiment) fixing protrusions 21c arranged around the bearing hole 21a at equal angular intervals. Each of the fixing protrusions 21c includes a substantially circular column shape. Each of the fixing protrusions 21c is parallel to the second axis O2 and extends towards a side opposite to the gear 17.
A relay plate 22 including a substantially annular shape and is fixed to the planetary gear 21 so as to rotate integrally with the planetary gear 21. The relay plate 22 is fixed to the planetary gear 21 in a manner that the relay plate 22 is overlapped with the planetary gear 21 in the axial direction. The relay plate 22 is provided with a through hole 22a which is coaxial with the bearing hole 21a and includes a substantially circular shape. The relay plate 22 is also provided with plural (four in the present embodiment) fixing holes 22b which are arranged around the through hole 22a at equal angular intervals and each of which includes a substantially circular shape. The fixing holes 22b face the respective fixing protrusions 21c, and inner diameters of the respective fixing holes 22b are set to be equivalent to outer diameters of the respective fixing protrusions 21c. As each of the fixing protrusions 21c is fitted into the corresponding fixing hole 22b, the relay plate 22 rotates integrally with the planetary gear 21. The relay plate 22 includes an attachment piece 22c formed in a substantially tongue-shape and extending radially outwardly at a predetermined angular position. The attachment piece 22c is formed with an attachment hole 22d including a substantially circular shape.
An output pin 23 serving as the output portion and including an axis which is parallel to the second axis O2 is fixedly attached to the relay plate 22. The output pin 23 includes a substantially circular stepped-column shape. The output pin 23 includes a main body 23a formed in a substantially circular column shape of which an outer diameter is larger than an inner diameter of the attachment hole 22d. The output pin 23 also includes an attachment portion 23b which is formed in a substantially circular column shape, of which an outer diameter is equivalent to the inner diameter of the attachment hole 22d, and which is provided to protrude from the main body 23a towards the attachment hole 22d. In a state in which the attachment portion 23b is inserted in the attachment hole 22d, the output pin 23 is fixedly attached to the relay plate 22 by, for example, crimping or welding. The center of the output pin 23 is positioned on the pitch circle of the external gear 21b. The output pin 23 includes a circular column portion 23c formed in a substantially circular column shape and having an outer diameter which is smaller than the outer diameter of the main body 23a. The circular column portion 23c is formed to protrude from the main body 23a towards a side opposite to the attachment portion 23b.
It is known that, as illustrated in
Consequently, in a case where the circle Cr and the circle Cm are regarded as the pitch circle of the internal gear 18c and the pitch circle of the external gear 21b, respectively, and the contact point CN is regarded as an engaging position of the external gear 21b and the internal gear 18c, the center O can be regarded as the center (the axis) of the support shaft 17c (the bearing hole 21a) and the point P can be regarded as the center (the axis) of the output pin 23. A distance L from the center of the supporting shaft 17c and the center of the output pin 23 coincides with a radius of the pitch circle of the external gear 21b. When the planetary gear 21 revolves counter-clockwise in the drawing along the internal gear 18c while the planetary gear 21 is self-rotating about the support shaft 17c, the center of the output pin 23 (that is, the point P) performs a linear motion along the straight line L2. That is, the output pin 23 performs the linear motion along the straight line L2 that is perpendicular to the first axis O1 and intersects with the first axis O1.
For example, when the planetary gear 21 revolves along the internal gear 18c counter-clockwise in
As illustrated in
The cable 30 is connected to a distal end portion of the circular column portion 23c passing through the elongated hole 24a. That is, as illustrated in
In the above-described configuration, as illustrated in
In the above-described state, when the support shaft 17c revolves counter-clockwise about the first axis O1 in association with the rotation of the gear 17, the planetary gear 21 revolves counter-clockwise about the first axis O1 along the internal gear 18c while performing the self-rotation about the support shaft 17c (the second axis O2) in the clockwise direction, as illustrated in the change from
The lower end of the panel 5 is connected to the cable core portion 32. Thus, for example, when the cable core portion 32 is pulled out from the outer tube 31 by the movement amount of the output pin 23, the lower end of the panel 5 is pulled by the cable core portion 32. To the contrary, when the cable core portion 32 is pushed back into the outer tube 31 by the movement amount of the output pin 23, the lower end of the panel 5 is pushed by the cable core portion 32. As described above, by pushing and pulling the cable core portion 32, the arch shape of the panel 5 is changed.
Next, operation and effect of the present embodiment will be described.
(1) In the present embodiment, even if the size of the gear 17 is as much as the inner diameter of the internal gear 18c, when the planetary gear 21 is revolved along the internal gear 18c, the output pin 23 can perform the linear motion by the movement amount which is as much as the inner diameter of the internal gear 18c. Consequently, the apparatus can be reduced more in size as a whole.
(2) In the present embodiment, the diameter D2 of the pitch circle of the external gear 21b is set to be a half of the diameter D1 of the pitch circle of the internal gear 18c, and the output pin 23 is arranged on the pitch circle of the external gear 21b. Accordingly, as the planetary gear 21 revolves along the internal gear 18c while self-rotating about the second axis O2, the linear motion of the output pin 23 can be naturally realized.
(3) In the present embodiment, a direction of the linear motion of the output pin 23 can be switched only by rotating the gear 17 in one direction. That is, the output pin 23 is allowed to perform the linear reciprocating motion by rotating the gear 17 only in one direction. Consequently, for example, in a case where the gear 17 is rotated by the motor 12, there is no need to switch a direction of rotation of the motor 12 and/or to detect the switching position. Thus, components, including a switch, which are needed to rotate the motor 12 forward and backward can be omitted. Consequently, an electrical circuit configuration can be more simplified, thereby reducing costs.
In addition, for example, unlike the case of Patent document 1 in which the rotary motion is converted into the linear motion with the use of the pinion and the rack as described in the [BACKGROUND ART], there is no need to restrict an amount of movement of the rack by providing a contact portion (a stopper) at a distal end of the rack wherein the rack and the pinion are in contact with each other at the contact portion. Accordingly, a large stress associated with the contact is not generated at the seat drive apparatus 10, and thus the apparatus is restricted from being worn and/or a life of the apparatus can be made longer. Strength required for the seat drive apparatus 10 an be reduced.
(4) In the present embodiment, because of the relay plate 22, the output pin 23 can be arranged in a deviated manner in the direction of the second axis O2 relative to the external gear 21b even in a case where the output pin 23 is arranged on the pitch circle of the external gear 21b. Consequently, for example, the linear motion of the output pin 23 can be realized without obstructing the engagement of the external gear 21b and the internal gear 18c with each other.
(5) In the present embodiment, the circular column portion 23c (the output pin 23) is supported by the cable terminal portion 33 fixedly attached to the cable core portion 32. Here, when the output pin 23 is caused to perform the linear motion in association with the rotational drive of the gear 17, the output pin 23 (the circular column portion 23c) self-rotates about the axis of the output pin 23 of its own in association with the revolution of the planetary gear 21. However, the rotations of the output pin 23 can be absorbed by the cable terminal portion 33 because the cable core portion 32 (the portion serving as an object of the drive) connected to the output pin 23 is provided with the cable terminal portion 33 (a bearing portion). Therefore, the movement along the direction of the linear motion can be enabled without causing a connecting portion, where the cable 30 is connected to the output pin 23, to swing about the axis of the output pin 23.
(6) In the present embodiment, the linear motion of the output pin 23 is transmitted to the cable 30 as it is, and the cable 30 can be pulled and pushed. Accordingly, for example, unlike a case where an appropriate lever connected to the cable (the cable core portion) is rotated to push and pull the cable, an arrangement space allowing the rotation of the lever does not need to be provided and/or resistance of the cable is not varied by the change of an angle at which the cable is pulled depending on a rotary position of the lever. In addition, there is no need to separating a fastening position (which corresponds to the outer tube locking portion 34) of the cable from the lever to inhibit the change of the angle. Consequently, the cable 30 can be arranged in the vicinity of the seat drive apparatus 10 in an integrated manner, thereby further reducing the space for the routing of the cable 30.
(7) In the present embodiment, the linear motion can be obtained only from the rolling motion (the self-rotation and the revolution) of the planetary gear 21 that is associated with the rotation of the gear 17, and thus the conversion apparatus with high efficiency and small loss caused by the wear. Consequently, for example, the motor 12 can be downsized, thereby saving weight and costs.
The aforementioned embodiment can be changed or modified as follows.
As illustrated in
A seat drive apparatus 50 including the configuration conforming to the seat drive apparatus 10 is built in the side portion of the seatback 3 at one side (the left side when facing the front direction of the seat 1). An output portion (which corresponds to the output pin 23) of the seat drive apparatus 50 is connected to a distal end of the release lever 41 via a cable 55 including the configuration conforming to the cable 30. The seat drive apparatus 50 causes the cable 55 to move back and forth, thereby pushing and pulling the distal end of the release lever 41, and thus the recliner 40 is switched to the restricted state or the allowed state. The occupant can adjust a tilt angle of the seatback 3 by using the function of the recliner 40.
The motion conversion apparatus for a vehicle may be applied to a release apparatus of a seat lock related to attachment and detachment of the seat itself and/or a release apparatus of a seatback lock engaging and disengaging the seatback with a striker of a body, in addition to the lock release apparatus of the recliner. Alternatively, the motion conversion apparatus for a vehicle may be applied to a release apparatus of, for example, a door lock engaging and disengaging a door of a vehicle with a striker of a vehicle body.
In the aforementioned embodiment, the support shaft 17c is protrudingly provided at the gear 17 and the bearing hole 21a supporting the support shaft 17c is formed at the planetary gear 21, however, the relation thereof may be reversed to each other. That is, the bearing hole may be formed at the gear 17 and the support shaft supported by the bearing hole may be protrudingly provided at the planetary gear 21.
In the aforementioned embodiment, the output pin 23 (the circular column portion 23c) may include a circular cylindrical shape and/or a circular truncated cone shape, a polygonal frustum shape or a polygonal prism shape, for example. In particular, in a case where the output pin 23 includes the frustum shape or the polygonal prism shape, it is desirable that an appropriate play is provided between the output pin 23 and the cable 30 (the cable terminal portion 33), so that the rotation of the output pin 23 is not transmitted to the cable 30 (the cable terminal portion 33) and does not make the cable 30 to rotate.
In the aforementioned embodiment, the output pin 23 (the circular column portion 23c) is protrudingly provided at the relay plate 22 and the cable terminal portion 33 (the bearing portion) supporting the output pin 23 (the circular column portion 23c) is provided at the cable 30, however, the relation thereof may be reversed to each other. That is, the bearing hole (the bearing portion) may be formed at the relay plate 22 and the circular column portion supported by the bearing hole (the bearing portion) may be provided in the protruding manner at the cable 30.
In the aforementioned embodiment, the relay plate 22 may be omitted and the output pin (23) may be protrudingly provided directly at the planetary gear 21. In this case, it is desirable that the output pin is extended from the external gear 21b at a radially inward side relative to the pitch circle of the external gear 21b, and that the circular column portion of the output pin at a distal end side is bent in, for example, a crank-shape such that the circular column portion is positioned on the pitch circle.
In the aforementioned embodiment, the output pin 23 is caused to perform the linear reciprocating motion by driving the gear 17 and so forth to rotate only in one direction. To the contrary, the output pin 23 may be caused to perform the linear reciprocating motion by driving the motor 12 to rotate in a normal direction and a reverse direction, based on the premise that a rotation range of, for example, the gear 17 is limited. In this case, an opening width of the elongated hole 24a in an extending direction can be smaller than the original maximum movement amount of the output pin 23. For example, the rotation direction of the motor 12 may be switched at a timing (or at a timing prior thereof) when the output pin 23 reaches an end portion of the elongated hole 24a and thus the output pin 23 is mechanically restricted from moving.
In the aforementioned embodiment, the attachment point (the output pin 23) of the cable 30 is arranged on the movement trajectory of the pitch circle of the external gear 21b (the rolling circle). However, even if the attachment point (the output pin 23) of the cable 30 is slightly deviated from the movement trajectory of the pitch circle of the external gear 21b (the rolling circle), the behavior of the output pin 23 is only a gentle curved motion (which can be substantially regarded as the linear motion) instead of the linear motion, which does not cause any problem to the operation of the cable 30.
In the aforementioned embodiment, plural output pins (23) rotating integrally with the planetary gear 21 and plural cables (30) connected to the respective output pins may be provided. In this case, by arranging the plural output pins on the pitch circle of the external gear 21b at different angular positions from each other, the plural cables connected to the respective output pins are allowed to move back and forth in such a manner that a phase difference is generated between the cables.
In the aforementioned embodiment, the configuration of the decelerator that reduces the speed of the rotation of the motor 12 (the rotary shaft 12a) and transmits the decelerated rotation to the gear 17 is an example. For example, in a case where a rated output of the motor 12 is high enough, it may be configured such that the decelerator is omitted and the motor 12 directly drives the gear 17 to rotate.
In the aforementioned embodiment, it may be configured such that the motor 12 is omitted and an appropriate input member corresponding to the gear 17 is manually rotated to drive, directly or indirectly.
In the aforementioned embodiment, for example, the seat drive apparatus 10 may be used for a side support adjustment apparatus for adjusting a holding performance of a seat which holds the occupant. The seat drive apparatus 10 may be used for a headrest height adjustment apparatus for adjusting a position of the headrest 4 in the up-and-down direction. The seat drive apparatus 10 may be used for an appropriate adjustment apparatus other than the above-described apparatuses.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-255105 | Dec 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/088132 | 12/21/2016 | WO | 00 |
