Seat driving apparatus

A seat driving apparatus includes: a tubular member into which an output shaft is fitted, into which an input shaft is fitted, and which includes a tubular portion and a pressing piece; a first biasing member biasing the tubular member in an axial line direction toward the input shaft; an intermediary member into which the tubular portion is loosely inserted and which is turnable about an axial line extending in a direction different from a direction of an axial line of the tubular member; a cam member supported turnably around an axial line extending in a direction different from the directions of the axial lines of the tubular member and the intermediary member, pressing the pressing piece via the intermediary member, and allowing the input shaft to fit into the tubular member; and a second biasing member biasing the cam member, wherein a counterface of the intermediary member pressing the pressing piece includes a curved surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2014-099850, filed on May 13, 2014, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a seat driving apparatus in which a positional adjustment mechanism is activated.

BACKGROUND DISCUSSION

JP 2013-107624A (Reference 1, FIGS. 36 to 38) discloses a known seat driving apparatus in the related art, for example. The apparatus includes a worm wheel that is an input shaft rotationally driven by the rotary motor, and for example, a tubular member into which a lifter shaft that is an output shaft linked to a lifter mechanism is fitted so as to integrally rotate therewith and to be relatively movable in an axial line direction. The tubular member includes a tubular portion and a flange-like pressing piece which protrudes outwardly from the tubular portion. The tubular member is fitted so as to cause the worm wheel to be integrally rotated in response to movement in the axial line direction toward the worm wheel. The tubular member is biased in the axial line direction toward the worm wheel by a compression spring interposed between the tubular member and the lifter shaft.

The seat driving apparatus includes an intermediary member into which the tubular portion is loosely inserted and which is turnable about an axial line extending in a direction different from a direction of an axial line of the tubular member, and a cam member which is turnable about an axial line extending in a direction different from the directions of the axial line of the tubular member and the axial line of the intermediary member. The cam member presses the pressing piece via a distal end portion of the intermediary member so as to release the fitted worm wheel from the tubular member against biasing force of the compression spring by pressing the distal end portion of the intermediary member when being at a neutral position. The cam member allows the worm wheel to fit into the tubular member biased by the compression spring in response to turning force from the neutral position. The cam member is biased so as to be held at the neutral position.

Incidentally, according to Reference 1, for example, there is a case where the tubular member and the worm wheel mesh with each other when being integrally rotated. Such meshing becomes evident in the upper limit and the lower limit within a range of positional adjustment, for example, by being applied with an excessive load when the turning of the lifter shaft is locked. At this time, there is a possibility that the fitted worm wheel is unlikely to be released from the tubular member. Meanwhile, it may be considered to cope therewith by increasing the biasing force for holding (restoring) the cam member at the neutral position. However, in this case, another disadvantage is caused in that operation force for turning the cam member from the neutral position increases.

SUMMARY

Thus, a need exists for a seat driving apparatus which is not suspectable to the drawback mentioned above.

An aspect of this disclosure is directed to a seat driving apparatus including a tubular member into which an output shaft leading to a positional adjustment mechanism is fitted, in which the output shaft integrally rotate therewith and is relatively movable in an axial line direction, into which an input shaft is fitted, in which integrally rotate therewith in response to movement in the axial line direction toward the input shaft rotationally driven by a rotary motor, and which includes a tubular portion and a pressing piece protruding outwardly from the tubular portion, a first biasing member that biases the tubular member in the axial line direction toward the input shaft, an intermediary member into which the tubular portion is loosely inserted and which is turnable about an axial line extending in a direction different from a direction of an axial line of the tubular member; a cam member that is supported turnably around an axial line extending in a direction different from the directions of the axial line of the tubular member and the axial line of the intermediary member, presses the pressing piece via the intermediary member so as to release the fitted input shaft from the tubular member against biasing force of the first biasing member by pressing a distal end portion of the intermediary member being separated from the axial line of the intermediary member when being at a neutral position, and allows the input shaft to fit into the tubular member biased by the first biasing member in response to turning force from the neutral position; and a second biasing member that biases the cam member so as to be held at the neutral position. A counterface of the intermediary member pressing the pressing piece includes a curved surface causing a pressing portion with which the pressing piece presses the intermediary member, to be separated from the axial line of the intermediary member in accordance with the cam member turning toward the neutral position.

DETAILED DESCRIPTION

Hereinafter, an embodiment of a seat driving apparatus will be described.

As illustrated inFIG. 1, a pair of lower rails1which are arranged side by side in a width direction of a seat and extend in a front-back direction are fixed to the floor of a vehicle, and an upper rail2is movably mounted on each of the two lower rails1in the front-back direction.

A bracket3made with a plate member stands on each of the two upper rails2. A seat6forming a seating portion for an occupant is supported by each of the two brackets3via a front link4and a rear link5which are respectively arranged in the front portion and the rear portion. The seat6is configured to include a seat cushion7forming a seating surface, a seatback8tiltably (turnably) supported by a rear end portion of the seat cushion7, and a headrest9supported by an upper end portion of the seatback8.

A front-back position of the seat6is adjustable by relatively moving the lower rails1and the upper rails2on both sides, and a vertical position thereof is adjustable by lifting and lowering the front links4and the rear links5on both sides. In the seat6, a tilt angle of the front portion of the seat cushion7is adjustable with respect to the rear portion thereof, and a tilt angle of the seatback8is adjustable with respect to the seat cushion7. Accordingly, a person sitting on the seat6can adjust a position of an eye level in accordance with one's physical stature, for example.

A driving apparatus10is attached to a side portion on one side of the seat cushion7(on the right side toward the front of the seat). As illustrated inFIG. 2, the driving apparatus10is joined to a rotary axis11aof a rotary motor11configured to be a brush motor, for example, of which the axial line extends in substantially the width direction of the seat, so as to be driven therewith, via an input torque cable12which is coaxial with the rotary axis11a.

In detail, the driving apparatus10includes a pair of main body cases16and17which are split into halves in an axial line direction of the rotary axis11a. The main body cases16and17are fastened with four screws19which penetrate four corners of the main body cases in parallel to the axial line direction of the rotary axis11a.

A substantially cylindrical holding portion16awhich is concentric with the input torque cable12(the rotary axis11a) protrudes from a main body case16on the rotary motor11side. Inside the holding portion16a, an annular bearing21is fitted and a substantially cylindrical bottomed plug PL is screwed thereto. A base end portion of a worm22disposed coaxially with the input torque cable12is pivotally supported by the bearing21. The worm22is joined to the input torque cable12inserted through the plug PL, at the base end portion of the worm22so as to integrally rotate therewith. A distal end portion of the worm22is pivotally supported by a main body case17on a side away from the rotary motor11.

A pair of worm wheels23and24of which axial lines respectively extend in the front-back direction on an upper side and a lower side of the worm22are arranged in the main body cases16and17, as the input shafts. The worm wheels23and24mesh with the worm22at skew positions differing from each other with respect to the worm22. The worm wheels23and24are mutually set at an equivalent reduction ratio of 1 or greater.

As collectively illustrated inFIGS. 7 and 8, one worm wheel23includes a gear portion25which meshes with the worm22on its upper side, includes a pair of shaft portions26protruding on the rear side and the front side of the gear portion25so as to be pivotally supported by the main body cases16and17, and includes a pair of fitting portions27protruding respectively on the rear side and the front side of the two shaft portions26. The outer shape of each fitting portion27exhibits a substantially three-vane shape in which a columnar shape28and three arc columnar shapes29extending from the columnar shape28in the radial direction at equivalent angles are combined. In each of the arc columnar shapes29, a pair of gradual change portions29aare formed on both side portions thereof in the circumferential direction so as to be gradually decreased in width in the circumferential direction toward the distal end. Accordingly, in each of the arc columnar shapes29, in a strict sense, the distal end is slightly decreased in width in the circumferential direction compared to the proximal end. The other worm wheel24is also configured to have the same configuration, and the gear portion25thereof meshes with the worm22on the lower side thereof.

As illustrated inFIG. 2, a lifter shaft31L and a tilt shaft31T as the output shafts are respectively and pivotally supported by the main body cases16and17on the rear side and the front side of the worm wheel23coaxially with the worm wheel23in postures symmetrical with each other. The lifter shaft31L is linked to a lifter mechanism M1which is the positional adjustment mechanism adjusting the vertical position of the seat6. The tilt shaft31T is linked to a tilt mechanism M2which is the positional adjustment mechanism adjusting the tilt angle of the front portion of the seat cushion7with respect to the rear portion thereof.

Moreover, a recliner shaft31R and a slide shaft31S as the output shafts are respectively and pivotally supported by the main body cases16and17on the rear side and the front side of the worm wheel24coaxially with the worm wheel24in postures symmetrical with each other. The recliner shaft31R is linked to a recliner mechanism M3which is the positional adjustment mechanism adjusting the tilt angle of the seatback8with respect to the seat cushion7. The slide shaft31S is linked to a slide mechanism M4which is the positional adjustment mechanism adjusting the front-back position of the seat6.

Therefore, when any one of the lifter shaft31L, the tilt shaft31T, the recliner shaft31R, and the slide shaft31S turns, the corresponding lifter mechanism M1, tilt mechanism M2, recliner mechanism M3, or slide mechanism M4is activated, thereby being adjusted to the intended seat position. In other words, in the embodiment, the seat position can be adjusted in the forward direction and the reverse direction in each of the lifter mechanism M1, the tilt mechanism M2, the recliner mechanism M3, and the slide mechanism M4, that is, a so-called eight-way power seat.

The lifter shaft31L, the tilt shaft31T, the recliner shaft31R, and the slide shaft31S have the same structure except for their disposition states and the like. Therefore, the peripheral structure of the lifter shaft31L will be described below as being representative.

As illustrated inFIGS. 7 and 8, the lifter shaft31L exhibits a substantially columnar shape, and the distal end portion of the lifter shaft31L extending from a bearing portion of the main body cases16and17to a side facing the worm wheel23forms an output shaft side fitting portion32. The lifter shaft31L also includes an outward flange33protruding in an intermediate portion in the axial line direction adjacent to the bearing portion of the main body cases16and17.

A tubular member35is interposed between the fitting portion27of the worm wheel23and the flange33of the lifter shaft31L. The tubular member35includes a tubular portion36and a flange-shaped pressing piece37protruding outward in the radial direction from the distal end facing the lifter shaft31L of the tubular portion36. The output shaft side fitting portion32is fitted into the tubular member35so as to integrally rotate with the lifter shaft31L and to be movable in the axial line direction with respect to the lifter shaft31L. A fitting hole38which can house the fitting portion27is formed in the tubular member35. In other words, the fitting hole38exhibits a shape in combination of a circular hole38ain which the columnar shape28of the fitting portion27is fitted and three arc holes38bin which the three arc columnar shapes29are fitted. The tubular member35moves to the worm wheel23side in the axial line direction, thereby causing the fitting hole38to house the fitting portion27so as to integrally rotate with the worm wheel23.

In other words, rotational force of the worm wheel23can be transmitted to the lifter shaft31L via the tubular member35as the fitting portion27fits in the fitting hole38in response to the movement of the tubular member35. As a fitted state between the fitting portion27and the fitting hole38is released, rotational force thereof cannot be transmitted to the lifter shaft31L via the tubular member35. The lifter mechanism M1is activated in response to the turning of the lifter shaft31L as described above. The fitting portion27of the worm wheel23, and the output shaft side fitting portion32and the tubular member35of the lifter shaft31L configure the clutch mechanism which selectively connects the worm wheel23and the lifter shaft31L.

The output shaft side fitting portion32of the lifter shaft31L is inserted through a compression spring39which is a first biasing member formed with a coil spring which is interposed between the tubular member35and the flange33on an inner circumferential side of the pressing piece37. The tubular member35is biased at all times to a side in which the fitting hole38houses in the fitting portion27of the worm wheel23due to the compression spring39, that is, a side in which rotational force of the worm wheel23can be transmitted to the lifter shaft31L. In other words, in a state where rotational force of the worm wheel23cannot be transmitted to the lifter shaft31L, the tubular member35moves to a side in which a fitting state between the fitting portion27and the fitting hole38is released against biasing force of the compression spring39.

The same clutch mechanism is configured between the worm wheel23and the tilt shaft31T, between the worm wheel24and the recliner shaft31R, and between the worm wheel24and the slide shaft31S so as to selectively connect them with each other.

The tubular portion36of each tubular member35is loosely inserted into an intermediary member40which is supported by the main body case16. In other words, as illustrated inFIGS. 4 and 5, a substantially semicircular groove-shaped bearing groove16bextending in a vertical direction (a direction orthogonal to the drawing sheet) between the pressing piece37of the tubular member35and the worm wheel23(24) which are adjacent to each other is formed in the main body case16.

Meanwhile, the intermediary member40includes a substantially superior arc columnar shaft portion41which is pivotally supported by the bearing groove16band includes a substantially square frame-shaped main body portion42crossing the tubular portion36of the tubular member35in a direction substantially orthogonal to the axial line direction. In the intermediary member40, the tubular portion36is loosely inserted into a substantially circular insertion through hole42aformed in the main body portion42. Therefore, the intermediary member40can turn about the bearing groove16bin a certain range without being hindered by the tubular portion36. The circumferential direction of this turning range is along movement direction of the tubular member35coinciding with the axial line direction thereof.

As illustrated on the left side inFIG. 5, when the main body portion42of the intermediary member40is widened along the pressing piece37of the tubular member35, that is, when the same is widened in a direction orthogonal to the axial line direction of the tubular member35, the tubular member35is biased by the compression spring39, thereby causing the fitting hole38to house the fitting portion27of the worm wheel23(24). Meanwhile, as illustrated on the right side inFIG. 5, when the main body portion42of the intermediary member40turns in a direction away from the worm wheel23(24) centering around the shaft portion41, the tubular member35of the pressing piece37pressed by the main body portion42moves in the axial line direction against biasing force of the compression spring39, thereby releasing the fitting hole38from the fitting portion27of the worm wheel23(24).

As illustrated inFIG. 8, a counterface of the main body portion42(the intermediary member40) which can press the pressing piece37forms a curved surface42bwhich is curved so as to be convex in the axial line direction approaching the pressing piece37. It is needless to mention that the curved surface42bis separately present in both the upper portion and the lower portion of the insertion through hole42a. Moreover, the distal end portion43of the intermediary member40on a side being separated from the shaft portion41bulges in a substantially triangular shape in the circumferential direction being separated from the pressing piece37centering around the shaft portion41so as to cause a central portion thereof in the vertical direction to be the apex.

As illustrated inFIGS. 3, 6A, and 6B, a pair of support axis portions17aand17barranged side by side in the front-back direction protrude in the main body case17toward the opposite side of the main body case16side by side in the axial line direction of the worm22(the rotary axis11a). In the main body case17, substantially arc columnar guide portions17cand17dprotrude on the upper side and the lower side of the support axis portion17aconcentric therewith, and substantially arc columnar guide portions17eand17fprotrude on the upper side and the lower side of the support axis portion17bconcentric therewith. In the main body case17, a switch cam support axis portion17gconcentric with the worm22protrudes toward the opposite side of the main body case16. The center of the switch cam support axis portion17gis disposed in the center between the two support axis portions17aand17b.

In the main body case17, substantially circular bearing holes17hand17iare respectively formed on the upper side and the lower side between the support axis portion17aand the switch cam support axis portion17g. The same bearing holes17hand17iare respectively formed on the upper side and the lower side between the support axis portion17band the switch cam support axis portion17g. A pair of first cam members51are respectively and pivotally supported by the two bearing holes17hon the upper side, and a pair of second cam members52are respectively and pivotally supported by the two bearing holes17ion the lower side.

As illustrated inFIG. 11A, the first cam member51includes a substantially columnar large diameter shaft portion51awhich is pivotally supported by the bearing hole17h, includes a substantially oval cam portion51bwhich protrudes inside the main body case17from the bearing hole17h, and includes a flange portion51cwhich protrudes toward the outside of the main body case17from the bearing hole17hand comes into sliding contact with an outer circumferential edge portion of the bearing hole17h. The first cam member51includes a gear portion51dwhich is adjacent to the flange portion51cand is disposed outside the main body case17, includes a columnar portion51ewhich is adjacent to the gear portion51dand is disposed farther outside the main body case17, and includes a substantially columnar small diameter shaft portion51fwhich is decreased in diameter more than that of the columnar portion51e.

As illustrated inFIGS. 7 and 8, in the first cam member51on the lifter shaft31L side, the cam portion51bis disposed so as to cause the cam portion51bto be able to come into contact with a distal end portion43of the intermediary member40on a side away from the shaft portion41and to come into contact with or to approach the outer circumferential surface of the tubular portion36of the tubular member35. In other words, the first cam member51causes the cam portion51bto press the pressing piece37of the tubular member35via the intermediary member40. When a longitudinal direction of the cam portion51bextends in a rotary position to coincide with the axial line direction of the tubular member35and the like, that is, the rotary position in which the tubular member35is caused to be farthest away from the worm wheel23(hereinafter, also referred to as “a neutral position” of the first cam member51), the fitting hole38of the tubular member35is released from the fitting portion27of the worm wheel23against biasing force of the compression spring39.

As illustrated on the left side inFIG. 5, when the longitudinal direction of the cam portion51bis deviated from the axial line direction of the tubular member35and the like in response to the turning thereof, the first cam member51allows movement of the tubular member35so as to cause the fitting hole38of the tubular member35biased by the compression spring39to house the fitting portion27of the worm wheel23. Meanwhile, the first cam member51presses the pressing piece37of the tubular member35with the cam portion51bvia the intermediary member40in response to the turning toward the neutral position, thereby moving the tubular member35against biasing force of the compression spring39and releasing the fitting hole38of the tubular member35from the fitting portion27of the worm wheel23. The first cam member51on the tilt shaft31T side is operated in the same manner.

Meanwhile, as illustrated inFIG. 11B, the second cam member52includes a substantially columnar large diameter shaft portion52awhich is pivotally supported by the bearing hole17i, includes a substantially oval cam portion52bwhich protrudes inside the main body case17from the bearing hole17i, and includes a flange portion52cwhich protrudes toward the outside of the main body case17from the bearing hole17iand comes into sliding contact with an outer circumferential edge portion of the bearing hole17i. The second cam member52includes a columnar portion52dwhich is adjacent to the flange portion52cand is disposed outside the main body case17, includes a gear portion52ewhich is adjacent to the columnar portion52dand is disposed farther outside the main body case17, and includes a substantially columnar small diameter shaft portion52fwhich is decreased in diameter more than that of the columnar portion52d. In other words, the first and second cam members51and52mutually have the same shape except that the gear portions51dand52eand the columnar portions51eand52dare alternately disposed in the axial line direction.

In the second cam member52on the recliner shaft31R side, the cam portion52bis disposed so as to cause the cam portion52bto be able to come into contact with the distal end portion43of the intermediary member40on a side away from the shaft portion41and to come into contact with or to approach the outer circumferential surface of the tubular portion36of the tubular member35. In other words, the second cam member52causes the cam portion52bto press the pressing piece37of the tubular member35via the intermediary member40. When the longitudinal direction of the cam portion52bextends in the rotary position to coincide with the axial line direction of the tubular member35and the like, that is, the rotary position in which the tubular member35is caused to be farthest away from the worm wheel24(hereinafter, also referred to as “a neutral position” of the second cam member52), the fitting hole38of the tubular member35is released from the fitting portion27of the worm wheel24against biasing force of the compression spring39.

When the longitudinal direction of the cam portion52bis deviated from the axial line direction of the tubular member35and the like in response to the turning thereof, the second cam member52allows movement of the tubular member35so as to cause the fitting hole38of the tubular member35biased by the compression spring39to house the fitting portion27of the worm wheel24. Meanwhile, the second cam member52presses the pressing piece37of the tubular member35with the cam portion52bvia the intermediary member40in response to the turning toward the neutral position, thereby moving the tubular member35against biasing force of the compression spring39and releasing the fitting hole38of the tubular member35from the fitting portion27of the worm wheel24. The second cam member52on the slide shaft31S side is operated in the same manner.

As illustrated inFIGS. 3, 6A, and 6B, a lifter operation handle53L is pivotally supported by a base end portion of the support axis portion17a. The lifter operation handle53L meshes with the gear portion51dof the first cam member51and includes a gear portion54L idling at a position of the columnar portion52dof the second cam member52. Therefore, for example, when the lifter operation handle53L is in turning operation, the first cam member51(the cam portion51b) turns in accordance with rotational force transmitted from between the gear portions54L and51d. Accordingly, the tubular member35moves in the axial line direction in the above-described state.

A torsion spring55as the second biasing member is wound about the support axis portion17awhich is the inner circumferential side of the lifter operation handle53L. The proximal end portions of hook portions55aat both ends of the torsion spring55come into contact with a stopper portion of the lifter operation handle53L so as to be wheel-locked, and the distal end portions of the hook portions55aare positioned by the guide portions17cand17d. The lifter operation handle53L is biased by the torsion spring55, thereby being held in a predetermined initial position extending toward the rear of the support axis portion17a. In this case, the first cam member51which integrally turns with the lifter operation handle53L is set so as to be disposed at the neutral position. The biasing force of the torsion spring55holding the lifter operation handle53L at the initial position is set to be greater than the biasing force of the compression spring39which moves the tubular member35so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel23.

Therefore, normally, the lifter operation handle53L is held at the initial position. In accordance therewith, the first cam member51is disposed at the neutral position. In other words, normally, the worm wheel23and the lifter shaft31L are held in a state so as not to be able to transmit rotational force therebetween via the tubular member35. When the lifter operation handle53L is in turning operation against biasing force of the torsion spring55, the first cam member51is deviated from the neutral position due to the turning of the first cam member51caused by the turning operation of the lifter operation handle53L, and then, the tubular member35moves so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel23due to biasing force of the compression spring39. Accordingly, rotational force of the worm wheel23can be transmitted to the lifter shaft31L via the tubular member35.

A recliner operation handle53R is pivotally supported by the distal end portion of the support axis portion17a. The recliner operation handle53R meshes with the gear portion52eof the second cam member52and includes a gear portion54R idling at a position of the columnar portion51eof the first cam member51. Therefore, for example, when the recliner operation handle53R is in turning operation, the second cam member52(the cam portion52b) turns in accordance with rotational force transmitted from between the gear portions54R and52e. Accordingly, the tubular member35moves in the axial line direction in the above-described state.

A torsion spring56as the second biasing member is wound about the support axis portion17awhich is the inner circumferential side of the recliner operation handle53R. The proximal end portions of hook portions56aat both ends of the torsion spring56come into contact with a stopper portion of the recliner operation handle53R so as to be wheel-locked, and the distal end portions of the hook portions56aare positioned by the guide portions17cand17d. The recliner operation handle53R is biased by the torsion spring56, thereby being held in a predetermined initial position extending toward the upper portion of the support axis portion17a. In this case, the second cam member52which integrally turns with the recliner operation handle53R is set so as to be disposed at the neutral position. The biasing force of the torsion spring56holding the recliner operation handle53R at the initial position is set to be greater than the biasing force of the compression spring39which moves the tubular member35so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel24.

Therefore, normally, the recliner operation handle53R is held at the initial position. In accordance therewith, the second cam member52is disposed at the neutral position. In other words, normally, the worm wheel24and the recliner shaft31R are held in a state so as not to be able to transmit rotational force therebetween via the tubular member35. When the recliner operation handle53R is in turning operation against biasing force of the torsion spring56, the second cam member52is deviated from the neutral position due to the turning of the second cam member52caused by the turning operation of the recliner operation handle53R, and then, the tubular member35moves so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel24due to biasing force of the compression spring39. Accordingly, rotational force of the worm wheel24can be transmitted to the recliner shaft31R via the tubular member35.

Meanwhile, a tilt operation handle53T is pivotally supported by the base end portion of the support axis portion17b. The tilt operation handle53T meshes with the gear portion51dof the first cam member51and includes a gear portion54T idling at a position of the columnar portion52dof the second cam member52. The operation of the tilt operation handle53T is the same as the operation of the lifter operation handle53L. In other words, normally, the worm wheel23and the tilt shaft31T are held in a state so as not to be able to transmit rotational force therebetween via the tubular member35. When the tilt operation handle53T is in turning operation against biasing force of the torsion spring55, the first cam member51is deviated from the neutral position due to the turning of the first cam member51caused by the turning operation of the tilt operation handle53T, and then, the tubular member35moves so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel23due to biasing force of the compression spring39. Accordingly, rotational force of the worm wheel23can be transmitted to the tilt shaft31T via the tubular member35.

A slide operation handle53S is pivotally supported by the distal end portion of the support axis portion17b. The slide operation handle53S meshes with the gear portion52eof the second cam member52and includes a gear portion54S idling at a position of the columnar portion51eof the first cam member51. The operation of the slide operation handle53S is the same as the operation of the recliner operation handle53R. In other words, normally, the worm wheel24and the slide shaft31S are held in a state so as not to be able to transmit rotational force therebetween via the tubular member35. When the slide operation handle53S is in turning operation against biasing force of the torsion spring56, the second cam member52is deviated from the neutral position due to the turning of the second cam member52caused by the turning operation of the slide operation handle53S, and then, the tubular member35moves so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel24due to biasing force of the compression spring39. Accordingly, rotational force of the worm wheel24can be transmitted to the slide shaft31S via the tubular member35.

As illustrated inFIG. 3, a lifter switch cam member61L, a tilt switch cam member61T, a recliner switch cam member61R, and a slide switch cam member61S having substantially annular shapes are pivotally supported by the switch cam support axis portion17g, in order from the base end to the distal end.

The lifter switch cam member61L is formed in the outer circumferential portion on a side facing the gear portion54L of the lifter operation handle53L, includes a gear portion62L meshing therewith, and also includes an arc portion63L formed in the outer circumferential portion on a side facing the gear portion54T of the tilt operation handle53T so as to be idling therein. Therefore, for example, when the lifter operation handle53L is in turning operation, the lifter switch cam member61L idles in the gear portion54T of the tilt operation handle53T in the arc portion63L and turns in accordance with rotational force transmitted from between the gear portions54L and62L.

The tilt switch cam member61T is formed in the outer circumferential portion on a side facing the gear portion54T of the tilt operation handle53T, includes a gear portion62T meshing therewith, and also includes an arc portion63T formed in the outer circumferential portion on a side facing the gear portion54L of the lifter operation handle53L so as to be idling therein. Therefore, for example, when the tilt operation handle53T is in turning operation, the tilt switch cam member61T idles in the gear portion54L of the lifter operation handle53L in the arc portion63T and turns in accordance with rotational force transmitted from between the gear portions54T and62T.

The recliner switch cam member61R is formed in the outer circumferential portion on a side facing the gear portion54R of the recliner operation handle53R, includes a gear portion62R meshing therewith, and also includes an arc portion63R formed in the outer circumferential portion on a side facing the gear portion54S of the slide operation handle53S so as to be idling therein. Therefore, for example, when the recliner operation handle53R is in turning operation, the recliner switch cam member61R idles in the gear portion54S of the slide operation handle53S in the arc portion63R and turns in accordance with rotational force transmitted from between the gear portions54R and62R.

The slide switch cam member61S is formed in the outer circumferential portion on a side facing the gear portion54S of the slide operation handle53S, includes a gear portion62S meshing therewith, and also includes an arc portion63S formed in the outer circumferential portion on a side facing the gear portion54R of the recliner operation handle53R so as to be idling therein. Therefore, for example, when the slide operation handle53S is in turning operation, the slide switch cam member61S idles in the gear portion54R of the recliner operation handle53R in the arc portion63S and turns in accordance with rotational force transmitted from between the gear portions54S and62S.

The lifter switch cam member61L, the tilt switch cam member61T, the recliner switch cam member61R, and the slide switch cam member61S respectively form the switch cam portions64L,64T,64R, and64S at the lower portion of the outer circumferential portion interposed between the gear portions62L,62T,62R, and62S and the arc portions63L,63T,63R, and63S.

As illustrated inFIG. 3, the driving apparatus10includes a cover18forming a casing thereof, in addition to the main body cases16and17. The cover18is fastened to the main body case17as two screws20penetrating parallel to the axial line direction of the rotary axis11aare respectively fastened to the two support axis portions17aand17bin a state of covering the main body case17from outside. Accordingly, the operation handles53L,53T,53R, and53S are positioned in the axial line direction. In this case, as the distal end of the switch cam support axis portion17gfits the cover18, the switch cam members61L,61T,61R, and61S are positioned in the axial line direction. Moreover, each of the first cam member51and the second cam member52is positioned in the axial line direction as the small diameter shaft portions51fand52fare pivotally supported by the cover18.

A switch support axis portion18aincluding the axial line extending on the lower side of the switch cam support axis portion17gto be in parallel to the axial line thereof protrudes from the cover18. A switch lever70disposed at the lower side of the switch cam portions64L,64T,64R, and64S is supported by the switch support axis portion18a. The switch lever70exhibits a bilaterally symmetrical shape, includes a substantially cylindrical bearing portion71which is pivotally supported by the switch support axis portion18a, and includes a flange72extending outward from the end portion on a side away from the cover18of the bearing portion71. A substantially fan-shaped columnar switch pressing portion73protruding downward is formed in the flange72. In the lower end portion of the flange72, a substantially arc columnar stopper piece74protrudes toward the cover18above the switch pressing portion73in parallel to the bearing portion71. Moreover, the switch lever70includes a substantially square columnar pressed portion75which is connected to the flange72at an angle position at the upper end. The pressed portion75is positioned on a farther outer circumferential side than the bearing portion71, and the length thereof in the axial line direction is set to be equivalent to the length of all of the switch cam members61L,61T,61R, and61S in the axial line direction in a state of being superposed. In other words, the pressed portion75extends along the direction so as to cover the positions of all of the switch cam members61L,61T,61R, and61S in the axial line direction.

A return spring77configured to be a torsion spring, for example, is wound about the bearing portion71which is on a farther inner circumferential side than the stopper piece74and the like. The proximal end portions of the hook portions77aat both ends of the return spring77come into contact with the stopper piece74so as to be wheel-locked, and the distal end portions of the hook portions77aare positioned at an engagement wall (not illustrated) of the cover18. As the switch lever70is biased by the return spring77, the pressed portion75is held at a predetermined initial turning position (the neutral position) extending upward.

Here, as illustrated inFIG. 6A, it is considered that all of the operation handles53L,53T,53R, and53S are not in operation and are disposed at a corresponding predetermined initial position. In this case, the pressed portion75of the switch lever70disposed at the initial turning position is disposed so as to block the turning track about the switch cam support axis portion17gof the switch cam portions64L,64T,64R, and64S of all of the switch cam members61L,61T,61R, and61S.

As illustrated in the changes shifted to that inFIG. 6B, if the slide switch cam member61S (a switch cam portion64S) is caused to turn counterclockwise by performing a clockwise turning operation of the slide operation handle53S, for example, the slide switch cam member61S presses the pressed portion75of the switch lever70with the switch cam portion64S. Accordingly, the switch lever70turns clockwise as illustrated centering around the switch support axis portion18a.

In contrast, when the slide switch cam member61S (the switch cam portion64S) is caused to turn clockwise as illustrated inFIG. 6Aby performing a counterclockwise turning operation of the slide operation handle53S, the slide switch cam member61S presses the pressed portion75of the switch lever70with the switch cam portion64S. Accordingly, the switch lever70turns counterclockwise as illustrated centering around the switch support axis portion18a.

As illustrated inFIGS. 3, 6A, and 6B, a support frame80is disposed below the switch lever70. The support frame80includes a pair of support pieces80aand80bopposing each other upwards from the lower end portion and being oriented in the front-back direction, and exhibits a substantially V-shape. In the upper end portion of each of the support pieces80aand80b, a joining protrusion portion80cprotrudes toward the cover18in parallel to the axial line direction of the support axis portions17aand17band the like. The support frame80is supported by the cover18as a screw81penetrating the lower end portion in parallel to the axial line direction of the joining protrusion portion80cand the like is fastened to the cover18, and the distal ends of the two joining protrusion portions80care fitted to the cover18.

The two support pieces80aand80brespectively support the first switch structure body86and the second switch structure body87below the joining protrusion portion80c. Each of the first switch structure body86and the second switch structure body87includes substantially rectangular column-shaped main body portions86aand87aextending in an extension direction of the two support pieces80aand80b, and includes buttons86band87bwhich can be upwardly in and out from the top surface in which the main body portions86aand87aface each other. The buttons86band87bare normally in a state of respectively protruding upwards from the top surfaces of the main body portions86aand87a, and are disposed so as to block the turning track centering around the switch support axis portion18aof the switch pressing portion73. Therefore, as illustrated in the change shifted to that inFIG. 6B, for example, when the switch lever70turns clockwise centering around the switch support axis portion18a, in accordance therewith, a button86bof the first switch structure body86is pressed downward by the switch pressing portion73. In contrast, when the switch lever70turns counterclockwise centering around the switch support axis portion18aas inFIG. 6A, in accordance therewith, a button87bof the second switch structure body87is pressed downward by the switch pressing portion73.

As illustrated inFIG. 12, each of the first switch structure body86and the second switch structure body87includes an electric circuit which is configured to have contact points CH1and CH2electrically connected to a high potential +V of a DC power source, contact points CL1and CL2electrically connected to a low potential GND, and movable terminals MT1and MT2connected to terminals of the rotary motor11different from each other. The two movable terminals MT1and MT2are respectively coupled to the two buttons86band87band are electrically connected to the contact points CL1and CL2on the low potential GND side, normally. The two movable terminals MT1and MT2are electrically connected to the contact points CH1and CH2on the high potential +V side as the two buttons86band87bare respectively pressed down. Therefore, when the switch lever70turns clockwise centering around the switch support axis portion18ain accordance with a turning operation of any one of the operation handles53L,53T,53R, and53S, the movable terminal MT1of the first switch structure body86of which the button86bis pressed down is electrically connected to the contact point CH1on the high potential +V side, thereby electrifying the rotary motor11through one polarity. In contrast, when the switch lever70turns counterclockwise centering around the switch support axis portion18a, the movable terminal MT2of the second switch structure body87of which the button87bis pressed down is electrically connected to the contact point CH2on the high potential +V side, thereby electrifying the rotary motor11through the opposite polarity.

Subsequently, the operation of the embodiment will be described. Each of the lifter operation handle53L, the tilt operation handle53T, the recliner operation handle53R, and the slide operation handle53S is substantially the same with each other except rotational force transmitted to the shafts31L,31T,31R, and31S related to the turning operation. Therefore, an operation of the lifter operation handle53L will be described below as being representative.

Firstly, it is considered that the lifter operation handle53L is not in operation, thereby being in a state where rotational force of the worm wheel23cannot be transmitted to the lifter shaft31L, and connection between the rotary motor11and the DC power source is blocked via the first and second switch structure bodies86and87. In this state, when the lifter operation handle53L is in a turning operation clockwise or counterclockwise against biasing force of the torsion spring55, the first cam member51turns in response to the rotational force transmitted through the gear portions54L and51d. Accordingly, the first cam member51is deviated from the neutral position, and the tubular member35moves so as to cause the fitting hole38of the tubular member35to house the fitting portion27of the worm wheel23by biasing force of the compression spring39. Then, rotational force of the worm wheel23can be transmitted to the lifter shaft31L via the tubular member35.

Meanwhile, when the lifter operation handle53L is in a turning operation clockwise or counterclockwise, in response to the rotational force transmitted through the gear portions54L and62L, the lifter switch cam member61L turns counterclockwise or clockwise coping with the operation direction of the lifter operation handle53L. In this case, the switch lever70is pressed by the switch cam portion64L coping with the rotational direction of the lifter switch cam member61L, thereby turning clockwise or counterclockwise about the switch support axis portion18a. Then, as the switch lever70turns about the switch support axis portion18a, the corresponding button between the buttons86band87bis pressed by the switch pressing portion73. Accordingly, the rotary motor11and the DC power source are connected to each other through the polarity coping with the pressed button between the buttons86band87b(the movable terminals MT1and MT2), and thus, the rotary motor11rotates normally or reversely. In other words, a button to be pressed is determined between the buttons86band87bby the operation direction of the lifter operation handle53L, thereby determining the rotational direction of the rotary motor11.

As the rotary motor11rotates, the rotational force thereof is transmitted to the lifter shaft31L via the input torque cable12, the worm22, the worm wheel23, and the tubular member35. Then, in response to the rotational force of the lifter shaft31L, the lifter mechanism M1is activated so as to lift and lower the seat6coping with the rotational direction.

Thereafter, when operating force of the lifter operation handle53L is cancelled, the lifter operation handle53L is biased by the torsion spring55and returns to the initial position. Accordingly, the first cam member51turns in response to the rotational force transmitted through the gear portions54L and51dagainst biasing force of the compression spring39, and thus, the first cam member51returns to the neutral position. The biasing force of the torsion spring55which causes the lifter operation handle53L to return to the initial position together with the first cam member51is greater than the biasing force of the compression spring39which moves the tubular member35, as described above. Accordingly, rotational force of the worm wheel23cannot be transmitted to the lifter shaft31L via the tubular member35.

Meanwhile, in accordance with returning of the lifter operation handle53L to the initial position, the lifter switch cam member61L turns in response to the rotational force transmitted through the gear portions54L and62L, and the switch lever70returns to the initial turning position together with the corresponding buttons86band87b, thereby blocking the connection between the rotary motor11and the power source. Accordingly, the rotary motor11stops rotating.

Other operation handles53T,53R, and53S are operated in the same manner.

Incidentally, as described above, in the main body portion42of the intermediary member40, the curved surface42bis molded so as to be convex in the axial line direction approaching the pressing piece37of the tubular member35. The curved surface42bis formed so as to cause the pressing portion of the pressing piece37pressed by the main body portion42to be separated from the axial line (the shaft portion41) in accordance with the first cam member51turning toward the neutral position.

Therefore, as illustrated inFIG. 9A, in a state where the worm wheel23is fitted into the tubular member35, and the intermediary member40(the main body portion42) is provided to be parallel to the pressing piece37, the intermediary member40is set so as to come into contact with the pressing piece37at a position P1(the pressing portion) relatively approaching the shaft portion41(a fulcrum a), by the curved surface42b. In other words, the position P1is disposed in the vicinity of the axial line of the tubular member35.

A position at which the cam portion51bof the first cam member51comes into contact with the distal end portion43of the intermediary member40is expressed as a position Po (the pressed portion), a separation distance (a length of an arm) with respect to the fulcrum a having the position Po as leverage is expressed as a distance Lo, pressing force (load) of the intermediary member40applied by the first cam member51(the cam portion51b) is expressed as fo, and a separation distance (a length of the arm) with respect to the fulcrum a having the position P1as a point of action is expressed as a distance L1(<Lo). In this case, releasing force (load) f1at the time of releasing the tubular member35from the worm wheel23in a state of being fitted therein is calculated as follows on the basis of the principle of “leverage”.
f1×L1=fo×Lo
f1=fo×Lo/L1

Since the distance Lo is greater than the distance L1such that (Lo/L1>1), it is confirmed that the releasing force f1increases with respect to the pressing force fo.

Meanwhile, as illustrated inFIG. 9B, in a state where the first cam member51reaches the neutral position, and the fitted worm wheel23is released from the tubular member35, the intermediary member40is set so as to come into contact with the pressing piece37at a position P1′ (the pressing portion) being relatively separated from the shaft portion41(the fulcrum a), by the curved surface42b.

A position at which the cam portion51bof the first cam member51comes into contact with the distal end portion43of the intermediary member40is expressed as a position Po′ (the pressed portion), a separation distance (a length of an arm) with respect to the fulcrum a having the position Po′ as leverage is expressed as a distance Lo′, pressing force of the intermediary member40applied by the first cam member51is expressed as fo′, and a separation distance with respect to the fulcrum a having the position P1′ as a point of action is expressed as a distance L1′ (≅Lo′). In this case, releasing force f1′ in a state where the fitted worm wheel23is released from the tubular member35is calculated in a similar manner as follows.
f1′=fo′×Lo′/L1′

Even though the distance Lo is slightly greater than the distance L1, since the distance Lo and the distance L1are approximately the same (Lo/L1≅1) with each other, it is confirmed that the releasing force f1is approximately the same with the pressing force fo of which the increase with respect to pressing force fo is insignificant. However, in this case, since an amount of movement in the axial line direction for being separated from the worm wheel23of the tubular member35coincides with an amount of movement in the same direction of the distal end portion43about the shaft portion41, the movement speed of the tubular member35increases.

FIG. 10is a graph illustrating a relationship between the turning quantity having the turning position of the intermediary member40inFIG. 9Aas the origin point, and a separation distance from the shaft portion41(the fulcrum a) of the pressing portion of the pressing piece37pressed by the intermediary member40(the curved surface42b). As illustrated in the same diagram, in the embodiment, when turning the intermediary member40by the curved surface42bso as to release the fitted worm wheel23from the tubular member35, the separation distance is set so as to gradually increase in accordance with the increase of the turning quantity thereof. In other words, when the first cam member51starts to turn toward the neutral position, releasing force increases with respect to the pressing force of the intermediary member40applied by the first cam member51. Accordingly, even though the releasing force gradually decreases as the fitted worm wheel23is released from the tubular member35, the movement speed of the tubular member35gradually increases.

As described above, the distal end portion43of the intermediary member40bulges in a substantially triangular shape so as to cause the central portion thereof in the vertical direction to be the apex. Accordingly, as illustrated inFIGS. 9A and 9B, the counterface of the distal end portion43(the intermediary member40) which can be pressed by the first cam member51includes a protrusion surface43afrom which the pressed portion pressed by the first cam member51protrudes toward the first cam member51in the circumferential direction centering around the axial line of the intermediary member40in accordance with the first cam member51turning toward the neutral position. Therefore, as the first cam member51approaches the neutral position, the pressed portion of the intermediary member40pressed by the first cam member51protrudes toward the first cam member51in the circumferential direction centering around the axial line thereof due to the protrusion surface43a, and thus, the turning quantity of the intermediary member40is increased as much as thereof. Accordingly, an amount of movement in the axial line direction of the tubular member35which is pressed in response to the turning of the intermediary member40is increased.

It is the same in the intermediary member40between the worm wheel23and the tilt shaft31T, between the worm wheel24and the recliner shaft31R, and between the worm wheel24and the slide shaft31S.

As described above in detail, according to the embodiment, the following effects can be achieved.

(1) In the embodiment, when the first cam member51(the second cam member52) starts to turn toward the neutral position in a state where the worm wheel23(24) is fitted into the tubular member35, it is possible to increase releasing force for releasing the fitted worm wheel23(24) from the tubular member35on the basis of “the principle of leverage” as the pressing portion approaches the axial line (the shaft portion41) of the intermediary member40by the curved surface42bwhile the intermediary member40presses the pressing piece37. Therefore, for example, even though the tubular member35and the worm wheel23(24) mesh with each other when being integrally rotated, the fitted worm wheel23(24) can be more reliably released from the tubular member35. Meanwhile, if the first cam member51(the second cam member52) approaches the neutral position, the pressing portion is separated from the axial line (the shaft portion41) of the intermediary member40by the curved surface42bwhile the intermediary member40presses the pressing piece37, it is possible to increase a movement speed of the tubular member35at the time of releasing the fitted worm wheel23(24) from the tubular member35.

(2) In the embodiment, the intermediary member40is provided to be parallel to the pressing piece37when seen therefrom in the axial line direction in a state where the worm wheel23(24) is fitted into the tubular member35. Therefore, when the first cam member51(the second cam member52) starts to turn toward the neutral position, the tubular member35moves in the axial line direction thereof as far as a distance equivalent to an amount of movement in the circumferential direction centering around the axial line (the shaft portion41) of the intermediary member40in the pressing portion of the pressing piece37caused due to the turning of the intermediary member40. Therefore, in response to the turning of the intermediary member40, it is possible to move the tubular member35more efficiently in the axial line direction thereof.

(3) In the embodiment, as the first cam member51(the second cam member52) approaches the neutral position, the pressed portion of the intermediary member40pressed thereby protrudes toward the first cam member51(the second cam member52) in the circumferential direction centering around the axial line thereof due to the protrusion surface43a, and thus, the turning quantity of the intermediary member40increases as much as thereof. Accordingly, it is possible to increase an amount of movement in the axial line direction of the tubular member35which is pressed in response to the turning of the intermediary member40. Moreover, without causing the cam portion51b(52b) to be unnecessarily elongated, the tubular member35can be sufficiently moved in the axial line direction thereof.

(4) In the embodiment, in the fitting portion27(the arc columnar shape29) of the worm wheel23or24, a gradual change portion29aof which play between the fitting hole38and the fitting portion27increases in response to movement in the axial line direction in which the worm wheel23or24and the tubular member35are separated from each other is formed. Therefore, for example, even though the tubular member35and the worm wheel23or24mesh with each other when being integrally rotated, if the worm wheel23or24and the tubular member35move slightly in the axial line direction so as to be separated from each other, the meshing state can be relaxed as much as the increased amount of play thereof. Thus, it is possible to smoothly release the fitted worm wheel23or24from the tubular member35.

(5) In the embodiment, when the first cam member51(the second cam member52) starts to turn toward the neutral position in a state where the worm wheel23or24is fitted into the tubular member35, the pressing portion is disposed in the vicinity of the axial line of the tubular member35by the curved surface42bwhile the intermediary member40presses the pressing piece37. Therefore, a load applied to the tubular member35is close to the axial line thereof. Therefore, deviation of the tubular member35(misalignment of the axial line) can be prevented, and thus, it is possible to smoothly release the fitted worm wheel23or24from the tubular member35.

(6) In the embodiment, since there is no need to unnecessarily increase the biasing force of the torsion springs55and56for holding (restoring) the first and second cam members51and52at the neutral position, it is possible to prevent an increase in operation force required when causing the operation handles53L,53T,53R, and53S to turn from the initial position.

(7) In the embodiment, the plurality of positional adjustment mechanisms (M1to M4) can be selectively activated with one rotary motor11, and the electrical configuration thereof can be simplified further. In addition, each of the plurality of tubular members35and the like (the clutch mechanisms) has a configuration (so-called shaft coupling) in which the output shaft (the lifter shaft31L, the tilt shaft31T, the recliner shaft31R, and the slide shaft31S) leading to the corresponding positional adjustment mechanism (M1to M4) is connected to the worm wheels23and24. Therefore, each of the plurality of tubular members35and the like (the clutch mechanisms) can be intensively disposed about the output shaft and the like, and thus, it is possible to decrease the apparatus further in size in the entirety thereof. Moreover, since the number of functions (the number of the positional adjustment mechanisms) regarding a positional adjustment of a seat can be as many increased as the number of the output shafts (four), it is possible to relax the constraints on the number of functions.

(8) In the embodiment, as the operation handles53L,53T,53R, and53S are caused to be in turning operations from the initial position, the rotary motor11can be electrified through the polarity coping with the operation direction by the first and second switch structure bodies86and87while connecting the corresponding clutch mechanism. Therefore, it is possible to rotate the rotary motor11normally or reversely in accordance with the operation direction of the operation handles53L,53T,53R, and53S. Thus, it is possible to set the operation direction of the operation handles53L,53T,53R, and53S and the adjustment direction of the positional adjustment mechanism (M1to M4) so as to have a relationship easier to be grasped.

The embodiment can be changed as follows.As indicated by the two-dot chained line inFIG. 10, in the end stage in which the first cam member51(the second cam member52) approaches the neutral position, the curved surface may have a uniform separation distance from the axial line (the shaft portion41) of the pressing portion with which the intermediary member40presses the pressing piece37, that is, the curved surface may satisfy a relationship of monotonous non-decreasing in which the separation distance does not decrease at least. In other words, the expression “causing the pressing portion of the pressing piece to be separated from the axial line of the intermediary member in accordance with the cam member turning toward the neutral position” also includes a transition in which there is at least no approach.In the embodiment, in place of the worm22and the worm wheels23and24, the helical gears which mesh with each other may be employed. In this case, rotation may be transmitted by performing speed reduction between the two helical gears, or may be transmitted at the equivalent speed.In the embodiment, in place of the gradual change portion29awhich is formed in the fitting portion27(the arc columnar shape29) of the worm wheel23or24, or in addition to the gradual change portion29a, the same gradual change portion may be formed in the arc hole38bof the tubular member35. Otherwise, the gradual change portion29aformed in the fitting portion27(the arc columnar shape29) of the worm wheel23or24may be omitted.In the embodiment, the fitting portion (27) of the worm wheel23or24may have a two-vane shape, a polygonal columnar shape, or an elliptical columnar shape. In other words, it is acceptable as long as the fitting portion and the fitting hole which can fit each other are combined so as to cause the worm wheel23or24and the tubular member35to be integrally rotatable. In all cases, it is preferable to form the gradual change portion of which play between the fitting portion and the fitting hole is increased in accordance with movement in the axial line direction in which the worm wheel23or24and the tubular member35are separated from each other, in at least one of the fitting portion and the fitting hole.In the embodiment, the protrusion surface43aof the distal end portion43of the intermediary member40may be omitted.In the embodiment, in a state where the worm wheel23or24is fitted into the tubular member35(refer toFIG. 9A), the intermediary member40may be widened in a tilted state with respect to the pressing piece37.In the embodiment, any one of the worm wheels23and24may be spared so as to provide a two-system output (that is, two positional adjustment mechanisms). Otherwise, an output which can be connected to the worm wheel23or24as one system may be employed.

Subsequently, technological idea that can be grasped from the above-described embodiments and other examples will be additionally described.

(A) The seat driving apparatus includes the operation member which is provided so as to correspond to the positional adjustment mechanism and is joined to the cam member so as to be driven therewith. The second biasing member holds the cam member at the neutral position by biasing the operation member so as to be held at the initial position.

An aspect of this disclosure is directed to a seat driving apparatus including a tubular member into which an output shaft leading to a positional adjustment mechanism is fitted, in which the output shaft integrally rotate therewith and is relatively movable in an axial line direction, into which an input shaft is fitted, in which integrally rotate therewith in response to movement in the axial line direction toward the input shaft rotationally driven by a rotary motor, and which includes a tubular portion and a pressing piece protruding outwardly from the tubular portion, a first biasing member that biases the tubular member in the axial line direction toward the input shaft, an intermediary member into which the tubular portion is loosely inserted and which is turnable about an axial line extending in a direction different from a direction of an axial line of the tubular member; a cam member that is supported turnably around an axial line extending in a direction different from the directions of the axial line of the tubular member and the axial line of the intermediary member, presses the pressing piece via the intermediary member so as to release the fitted input shaft from the tubular member against biasing force of the first biasing member by pressing a distal end portion of the intermediary member being separated from the axial line of the intermediary member when being at a neutral position, and allows the input shaft to fit into the tubular member biased by the first biasing member in response to turning force from the neutral position; and a second biasing member that biases the cam member so as to be held at the neutral position. A counterface of the intermediary member pressing the pressing piece includes a curved surface causing a pressing portion with which the pressing piece presses the intermediary member, to be separated from the axial line of the intermediary member in accordance with the cam member turning toward the neutral position.

With this configuration, when the cam member starts to turn toward the neutral position in a state where the input shaft is fitted into the tubular member, it is possible to increase releasing force for releasing the fitted input shaft from the tubular member as the pressing portion approaches the axial line of the intermediary member by the curved surface while the intermediary member presses the pressing piece. Therefore, for example, even though the tubular member and the input shaft mesh with each other when being integrally rotated, the fitted input shaft can be more reliably released from the tubular member. Meanwhile, if the cam member approaches the neutral position, the pressing portion is separated from the axial line of the intermediary member by the curved surface while the intermediary member presses the pressing piece, it is possible to increase a movement speed of the tubular member at the time of releasing the fitted input shaft from the tubular member.

In the seat driving apparatus according to the aspect of this disclosure, it is preferable that the intermediary member is provided to be parallel to the pressing piece when seen from the intermediary member in the axial line direction in a state where the input shaft is fitted into the tubular member.

With this configuration, when the cam member starts to turn toward the neutral position, the tubular member moves in the axial line direction thereof as far as a distance equivalent to an amount of movement in the circumferential direction centering around the axial line of the intermediary member in the pressing portion of the pressing piece caused due to the turning of the intermediary member. Therefore, in response to the turning of the intermediary member, it is possible to move the tubular member more efficiently in the axial line direction thereof.

In the seat driving apparatus according to the aspect of this disclosure, it is preferable that the counterface of the intermediary member pressed by the cam member includes a protrusion surface from which a pressed portion pressed by the cam member protrudes toward the cam member in a circumferential direction centering around the axial line of the intermediary member in accordance with the cam member turning toward the neutral position.

With this configuration, as the cam member approaches the neutral position, the pressed portion of the intermediary member pressed by the cam member protrudes toward the cam member in the circumferential direction centering around the axial line thereof due to the protrusion surface, and thus, the turning quantity of the intermediary member increases as much as thereof. Accordingly, it is possible to increase an amount of movement in the axial line direction of the tubular member which is pressed in response to the turning of the intermediary member.

In the seat driving apparatus according to the aspect of this disclosure, it is preferable that the input shaft that includes a fitting portion which is fitted into a fitting hole formed in the tubular member, and integrally rotates with the tubular member as the fitting portion is inserted into the fitting hole. In at least one of the fitting hole and the fitting portion, it is preferable to form a gradual change portion of which play between the fitting hole and the fitting portion increases in response to movement in the axial line direction in which the input shaft and the tubular member are separated from each other.

With this configuration, for example, even though the fitting hole and the fitting portion mesh with each other when the tubular member and the input shaft are integrally rotated, if the input shaft and the tubular member move slightly in the axial line direction so as to be separated from each other, the meshing state can be relaxed as much as the increased amount of play thereof. Thus, it is possible to smoothly release the fitted input shaft from the tubular member.

In the seat driving apparatus according to the aspect of this disclosure, it is preferable that the seat driving apparatus further includes an operation member that is provided to correspond to the positional adjustment mechanism, is joined to the cam member and is driven with the cam member, and the second biasing member holds the cam member at the neutral position by biasing the operation member so as to be held at the neutral position.

The aspect of this disclosure provides an effect in which a connection state between an input shaft and an output shaft can be reliably cut off.