Torque transfer control mechanism and seat structure

A torque transfer control mechanism that suppresses output-side displacement, and including a rotation control unit that maintains a locked state when an input torque rotating a transfer mechanism is not applied, and releases the locked state when the transfer mechanism rotates. The rotation control unit includes an internal gear and lock plates that include outer teeth that can engage with inner teeth of the internal gear. When an input torque is not applied, the inner teeth of the internal gear engage with the outer teeth of the lock plates, and when the transfer mechanism is rotated, engagement between the inner teeth and the outer teeth is released. Thus, even when torque is applied from the output unit side, engagement between the inner teeth and the outer teeth is not released by the torque.

TECHNICAL FIELD

The present invention relates to a torque transfer control mechanism and a seat structure including the torque transfer control mechanism.

BACKGROUND ART

For example, as disclosed in Patent Document 1, as a lifter mechanism of a seat structure, a mechanism in which, when a transfer mechanism (in Patent Document 1, a mechanism configured by including an operation lever, a lever base, a lock base, a locked member, and an operation shaft) rotates from a neutral position by input torque, an output unit rotates to rotate a pinion and a sector gear connected to the output unit and lift a seat cushion, is known.

In Patent Document 1, in between the transfer mechanism and the output unit, a brake drum for transfer controlling the input torque to the output unit is interposed. The brake drum has an outer cylinder and an inner cylinder (in Patent Document 1, the inner cylinder is commonly used as the output unit connected to the pinion). In between the outer cylinder and the inner cylinder, a pair of two brake springs is installed. The inner cylinder is connected to the operation shaft composing the transfer mechanism. Each end portion of each brake spring is engaged to the inner cylinder and the pinion. When the operation shaft rotates in any direction by the input torque added to the operation lever and accordingly, the inner cylinder rotates in any direction, each brake spring acts in a reduced diameter direction to enable the inner cylinder to rotate, and transfer the force to the pinion. On the other hand, when a force that rotates the inner cylinder is imparted from the pinion or the like that is an output side, each brake spring acts in an increased diameter direction to disable the inner cylinder to rotate by contacting to an inner circumferential surface of the outer cylinder. Thereby, the operation shaft is prevented from rotating due to a load of the seat cushion side, and the seat cushion that is adjusted to a predetermined height by operation of the operation lever can maintain its position.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: Japanese Patent Application Publication No. 2007-118695

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

The torque transfer control mechanism used in the lifter mechanism of Patent Document 1 uses the brake spring as described above and only counteracts to an input from the seat cushion side (output side) by the friction force of the brake spring. Therefore, when a load input is repeated from the seat cushion side by vibration during the travel or the like, the inner cylinder rotates even a little counteracting to the friction force by the brake spring and the seat cushion may be deteriorated gradually.

The present invention has been made in consideration of the above, and has a problem of providing a torque transfer control mechanism capable of preventing displacement of an output side of a seat cushion or the like more reliably than conventional mechanisms even when input is performed from the output side due to vibration during the travel or the like, and a seat structure including the torque transfer control mechanism.

Means for Solving the Problem

In order to solve the problem, the torque transfer control mechanism of the present invention is continuously installed with: a transfer mechanism that rotates in a range of a predetermined angle from a neutral position by application of an input torque, and returns to the neutral position by a return spring when the input torque is not applied; and a rotation control unit that becomes a locked state when the input torque rotating the transfer mechanism is not applied and becomes a lock-released state when the transfer mechanism rotates by the input torque, and transfers the torque to the output unit during the lock-released state. In the torque transfer control mechanism, the transfer mechanism is imparted with the input torque to rotate the output unit. The rotation control unit has: an internal gear formed with inner teeth in an inner circumference; a plurality of lock plates installed in a range of the inner circumference of the internal gear, and formed with outer teeth in an outer circumferential surface that engage with the inner teeth of the internal gear in the locked state, and release engagement with the inner teeth in the lock-released state; and a rotation plate including a contact surface that guides each of the lock plates radially outward. An angle between the contact surface with the lock plates in the rotation plate and a contact surface with the outer teeth of the lock plates in the inner teeth of the internal gear is set smaller than a friction angle. Thus, in the locked state, even when the rotation plate attempts to rotate by the torque applied from the output unit, engagement between the outer teeth of the lock plates and the inner teeth of the internal gear is not released.

The torque transfer control mechanism preferably has the following configuration. The rotation plate is formed to be a substantially rhombus shape. An inclined side surface of the rhombus shape is a contact surface with the lock plates. A spring member that energizes the lock plates in a direction of approaching to the inclined side surface of the rotation plate is installed. By the lock plates being energized in the direction of approaching to the inclined side surface of the rotation plate by the spring member, the lock plates are pushed out radially outward along the inclined side surface of the rotation plate, and are energized in a direction engaging with the inner teeth of the internal gear. An elastic force of the spring member reduces backlash between components including the internal gear, the lock plates, and the rotation plate.

The torque transfer control mechanism preferably has the following configuration. The plurality of lock plates are installed in correspondence with each of the inclined side surfaces of the rotation plate that has a substantially rhombus shape. The mechanism has a first engaged portion that engages with engaging portions provided in each of the plurality of lock plates and a second engaged portion that engages with an engaging portion provided in the rotation plate. An input plate that rotates by the input torque is further included. When the input plate rotates, among the lock plates engaged via the first engaged portion, the lock plates of one pair of two related to one set that face each other diagonally and are towed in the rotation direction according to the rotation of the input plate rotate in the same direction to release engagement between the outer teeth of each of the lock plates and the inner teeth of the internal gear. By the input plate further rotating in the same direction, the rotation plate engaged via the second engaged portion rotates to generate a gap instantly in a space with the inclined side surface of the rotation plate. By the elastic force of the spring member, engagement between the outer teeth of the lock plates of one pair of two related to the other set that face each other diagonally and the inner teeth of the internal gear is released and the lock-released state is established. When, by rotation of the rotation plate, the output unit connected to the rotation plate rotates and application of the input torque is lost, by the elastic force of the spring member, each of the lock plates is energized in the direction of approaching to the inclined side surface of the rotation plate, and is pushed out along the inclined side surface of the rotation plate, and the outer teeth of each of the lock plates engage with the inner teeth of the internal gear and the locked state is established.

The spring member is preferably provided in correspondence with each set so that bottom portions are adjacent to each other in the circumference direction and so as to energize a set of two lock plates that slide in the same direction along each inclined side surface of the rotation plate, in the direction of approaching to each inclined side surface.

Other spring member that energizes the rotation control unit and the output unit in a separating direction is preferably further provided between the rotation control unit and the output unit.

The transfer mechanism is preferably configured to include a manual operation unit or an electric operation mechanism and be applied with the input torque manually or electrically.

The torque transfer control mechanism of the present invention is preferably used by being incorporated in a lifter mechanism of a seat structure, a reclining mechanism, or a lumbar control mechanism.

The seat structure of the present invention is characterized by including a lifter mechanism, a reclining mechanism, or a lumbar control mechanism incorporated with the torque transfer control mechanism.

Effect of the Invention

According to the present invention, a rotation control unit is included that maintains a locked state when the input torque that rotates the transfer mechanism is not applied and becomes a lock-released state when the transfer mechanism rotates by the input torque. The rotation control unit is configured to have the internal gear and the lock plates including the outer teeth that can engage with the inner teeth of the internal gear. When the input torque that rotates the transfer mechanism is not applied, the rotation control unit becomes a state where the inner teeth of the internal gear and the outer teeth of the lock plates engage with each other. When the transfer mechanism is rotated, the engagement is released. That is, it is locked by engagement between teeth of gears and only when the torque is applied to the transfer mechanism, this engagement between the teeth is released. Therefore, even when the torque is applied from the output unit side, depending on the torque, engagement between the inner teeth of the internal gear and the outer teeth of the lock plates is not released, and a mechanism connected to the output unit by the torque applied to the output unit is prevented from being displaced gradually, more reliably than conventional ones. Accordingly, for example, when it is used in a lifter mechanism of a seat structure of a vehicle or the like, even when the torque is applied to the output unit from the seat cushion side by vibration during the travel or the like, the seat cushion is not deteriorated gradually.

In addition, a configuration is preferable in which the lock plates are installed between the inclined side surface in the rotation plate having the substantially rhombus shape and the inner teeth of the internal gear, and a spring member that energizes the lock plates in a direction of approaching to the inclined side surface of the rotation plate is provided. The lock plates are energized to be pushed out in a direction of approaching to the inclined side surface of the rotation plate and engaging with the inner teeth of the internal gear along the inclined side surface. Thus, backlash between components including the internal gear, the lock plates, and the rotation plate is reduced by the elastic force of this spring member. Therefore, when the lock plates are incorporated as a lifter mechanism in a seat structure of a vehicle or the like, an abnormal sound generated due to backlash by being affected by vibration or the like during the travel can be prevented.

DESCRIPTION OF THE EMBODIMENTS

Following further describes the present invention in detail on the basis of the embodiments shown in the drawings.

FIG. 1shows a cushion frame3having a lifter mechanism2incorporated with a torque transfer control mechanism1according to an embodiment of the present invention. The cushion frame3is supported by upper rails42,42of a pair of sliders4,4. The lifter mechanism2has front links21,21and back links22,22arranged between the upper rails42,42and side frames31,31composing the cushion frame3, and has a spiral spring5that energizes the cushion frame3(side frames31,31) upward with respect to the upper rails42,42. In addition to these, the lifter mechanism is configured by including the torque transfer control mechanism1according to the present embodiment.

As shown inFIG. 2toFIG. 4, the torque transfer control mechanism1is configured by having a transfer mechanism110, a rotation control unit120, and an output unit130. When an input torque that rotates the transfer mechanism110is imparted, the rotation control unit120becomes a lock-released state in which the torque is transferred, and the output unit130rotates via the rotation control unit120. When the force to impart the input torque is lost, the rotation control unit120becomes the locked state. When the rotation control unit120is in the locked state, even when a torque is applied to the output unit130, the locked state is not released by the torque. The torque transfer control mechanism1is such mechanism. Following further describes its configuration in detail.

The transfer mechanism110is configured by having a lever111, a cover member112, a shaft113, a retainer114, a cam115, rollers116, a first spring117, a second spring118, and the like. The lever111has a predetermined length as shown in an imaginary line inFIG. 1. A base part111aof the lever111is provided rotatably in an outer surface side of the cover member112. The base part111acan rotate both of forward and reverse directions with respect to the cover member112and rotates by the input torque being imparted to either forward or reverse direction. In an inner circumferential side of the cover member112, the shaft113is installed. One end portion113aof the shaft113fits to a fitting hole111bprovided in the base part111aof the lever111via a through hole112dprovided in the cover member112. When the lever111is rotated, accordingly, the shaft113rotates together. In the present embodiment, the lever111is a manual operation unit operated manually. However, a motor (not shown) can be connected to the base part111ainstead of the manual lever111and the lever111can be an electrical operation mechanism in which the base part111arotates in forward and reverse directions electrically.

The cover member112has a cylindrical part112a, and attachment pieces112b,112bthat protrude right and left of the cylindrical part112a. The attachment pieces112b,112bare attached along with an internal gear124of the rotation control unit120described later to an outer surface of one side frame31composing the cushion frame3by using a spring. A substantially half of a lower side of a circumferential surface of the cylindrical part112aof the cover member112is cut out other than a cover protruding piece112cthat protrudes inward (a direction in which the rotation control unit120is arranged, and that is opposite direction from the lever111side) in a substantially center portion of the cylindrical part112a. Rotation ranges of the lever111at a time of forward and reverse rotation are between one end edge112c1of the cover protruding piece112cand one cutout end surface112a1of the cylindrical part112aand between the other end edge112c2of the cover protruding piece112cand the other cutout end surface112a2of the cylindrical part112a.

In the cylindrical part112aof the cover member112, the retainer114is further installed. The retainer114is formed in a substantially disk shape. In an inner surface (opposite surface from the base part111aside of the lever111contacting with the cover member112), a partition wall part114ais erected along a circumferential direction. The partition wall part114ais cut out for every predetermined length in a circumferential direction and the cutout portion is a roller arrangement groove114b. The roller arrangement groove114bis formed in six with equal intervals in the present embodiment. However, the number of formation is not limited to that. The retainer114is formed with one retainer protruding piece114cthat protrudes inward similarly to the cover protruding piece112c, from a circumferential surface of the retainer114.

In a range of an inner circumference of the partition wall part114aof the retainer114, the cam115is installed. In the roller arrangement groove114b, the rollers116are arranged. As shown inFIG. 4andFIG. 5, the cam115is formed by a substantially hexagon plate-shape body. Each side of the cam115is formed to be a substantially valley-shape in which a substantially center part115arecesses toward a center direction of the cam115. In a neutral position shown inFIG. 5(a), the substantially center part115aof each side of the cam115is set in a position so that the rollers116arranged in each roller arrangement groove114bof the retainer114face each other. Accordingly, when the cam115attempts to rotate in either forward or reverse direction from this position, as shown inFIG. 5(b)andFIG. 5(c), any of inclined side parts115bholding the substantially center part115atherebetween pushes the rollers116radially outward (arrow a direction shown inFIG. 5(c)).

The retainer114is supported by the first spring117. While the first spring117is formed to be a substantially circle shape, the first spring117is bent at substantially 90 degrees so as to protrude in the same direction, before the end portions117a,117aoverlap each other. In the retainer114, through holes114e,114eare formed with a narrower interval than an interval between the end portions117a,117aof the first spring117. In correspondence with the through holes114e,114e, spring engagement holes115c,115cto which each of end portions117a,117aof the first spring117are inserted, are formed in the cam115. Accordingly, when each of the end portions117a,117ais engaged with the spring engagement holes115c,115c, of the cam115via the through holes114e,114e, in a state where the first spring117is located at the outer surface side of the retainer114, the first spring117is engaged with its diameter reduced, and thereby elasticity always acts in the increased diameter direction. Due to the elastic force, the cam115in the partition wall part114aof the retainer114is maintained in the neutral position described above (position inFIG. 5(a)).

In the retainer114, a circular central hole114dhaving a predetermined diameter is formed by penetrating. In correspondence with the central hole114d, a fitting hole115dthat fits to the other end portion113bof the shaft113is formed in the center of the cam115. Thereby, when the shaft113rotates in either forward or reverse direction by the lever111, the cam115rotates in either forward or reverse direction and pushes the rollers116radially outward as described above (seeFIGS. 5(b), (c)). When the input of the input torque that rotates the lever111and the shaft113is lost, a relative position of the cam115with respect to the retainer114is made return to the neutral position (position inFIG. 5(a)) by the elastic force of the first spring117.

As shown inFIG. 5(a), the retainer protruding piece114cof the retainer114and the cover protruding piece112cof the cover member112are set so that a position where they overlap each other is a neutral position. When the rollers116are pushed radially outward as shown inFIGS. 5(b) and (c)with respect to the cover member112fixedly arranged, and the retainer114starts to rotate along with an input plate121described later, the retainer protruding piece114cseparates from the cover protruding piece112cin a circumferential direction as shown inFIG. 5(d). The second spring118is installed to make the retainer protruding piece114creturn to the neutral position where the retainer protruding piece114coverlaps the cover protruding piece112c. The second spring118is formed to be a spiral shape and is formed by each end portions118a,118abeing bent outward in the circumferential direction. Each end portions118a,118aof the second spring118is crossed in the circumferential direction and is engaged to the retainer protruding piece114cand the cover protruding piece112cthat are aligned to overlap each other.

Thereby, when the position of the retainer protruding piece114cwith respect to the cover protruding piece112cattempts to deviate slightly in the circumferential direction, the second spring118attempts to reduce its diameter, and thereby an elastic force to return the position in a direction of the neutral position acts (seeFIG. 5(d)). Since the elastic force of the second spring118is applied, when the cam115attempts to rotate according to the rotation of the shaft113, the cam115slightly rotates independently from the retainer114, then the roller116is pushed radially outward as described above, and pushes an end wall of each roller arrangement groove114bin the partition wall part114ato rotate the retainer114. That is, when the cam115rotates, since the relative position with the retainer114is deviated from the neutral position, when imparting of the input torque is lost, the first spring117returns the relative position to the neutral position.

Next, the rotation control unit120will be described. As shown inFIG. 3,FIG. 4, andFIG. 6, the rotation control unit120is configured by having an input plate121, a rotation plate122, lock plates123, an internal gear124, a third spring125, a fourth spring126, a fifth spring127, and a sixth spring128. The rotation control nit120is provided adjacent to the transfer mechanism110on the same shaft having the same rotation center as the transfer mechanism110.

The input plate121has a predetermined thickness. A surface side of the input plate121that is adjacent to the retainer114and the cam115is formed with a peripheral wall part121a. In a circular recess part surrounded by the peripheral wall part121a, the partition wall part114aand the rollers116of the retainer114are accommodated (seeFIG. 3). The inner diameter of the peripheral wall part121ais formed to be slightly larger than the outer diameter of the partition wall part114aof the retainer114. The input plate121is installed so that the peripheral wall part121ais located at the periphery of the partition wall part114aof the retainer114. Thus, in the transfer mechanism110, when the cam115rotates in any direction and the roller116is pushed radially outward, the roller116is pushed to the inner circumferential surface of the peripheral wall part121a(seeFIGS. 5(b) and (c)). As a result, when the cam115rotates, the input plate121starts to rotate along with the retainer114.

In the present embodiment, the input plate121is classified as being included in the rotation control unit120. However, rotation control is performed by that the input plate121starts to rotate, and first engaged portions121b,121band second engaged portions121c,121cformed in the input plate121perform a predetermined function as described later. Therefore, the input plate121may be classified as being included in the transfer mechanism110. The other components including the first engaged portions121b,121band the second engaged portions121b,121cmay be regarded as the rotation control unit120by regarding the components up to the peripheral wall part121aas the transfer mechanism110, functionally. In any way, which of the transfer mechanism110or the rotation control unit120is regarded to include the input plate121does not affect interpretation of claims at all.

The input plate121includes two first engaged portions121b,121b, and two second engaged portions121c,121c, that are opened in the opposite surface from the surface formed with the peripheral wall part121athat is adjacent to the retainer114. The first engaged portions121b,121band the second engaged portions121c,121cmay be groove shapes and may be hole shapes extending through the input plate120in the thickness direction. Also, a center hole121dis provided in which a shaft member129for centering is inserted, in the center. The component applied with the reference numeral129ais a detachment prevention ring of the shaft member129(seeFIG. 3andFIG. 4).

As shown inFIG. 3(b),FIG. 4, andFIG. 6(b) to (e), the first engaged portions121b,121bare formed to be arc shapes having a predetermined length in the circumferential direction, in symmetry by holding the center hole121dtherebetween.FIGS. 6(b) to (e)are plan views viewed from an arrow A direction inFIG. 6(a). Thus, the input plate121not drawn inFIG. 6(a)is not shown. However, for convenience of description, in the input plate121, the shapes of the first engaged portions121b,121band the second engaged portions121c,121cand relative positions are shown together. In the present embodiment, four lock plates123are provided (hereinafter, in some cases, the lock plate123arranged in the upper left inFIG. 6(b)refers to a first lock plate, the lock plate123arranged in the upper right refers to a second lock plate, the lock plate123arranged in the lower right refers to a third lock plate, and the lock plate arranged in the lower left refers to a fourth lock plate). Engaging portions (lock plate engaging portions)123eprovided in the four lock plates123engage with the first engaged portions121b,121b. In the present embodiment, among the four lock plate engaging portions123e, two lock plate engaging portions123e,123eof two lock plates123,123of which outside surface parts123d,123dare adjacent to each other in the circumferential direction (a set of the first lock plate123and the second lock plate123, and a set of the third lock plate123and the fourth lock plate123) are provided so as to each engage with one of the first engaged portions121b. However, the first engaged portions121bmay be shorter in the circumferential direction than that shown inFIGS. 6(b) to (d), may be formed in four in symmetrical positions, and may be configured so that each one of the first engaged portions121bengages to each of four lock plate engaging portions123e. Relationship between the first engaged portions121band the lock plate engaging portions123ewill be further described later.

The second engaged portions121c,121care formed to be an arc shape having a shorter length than the first engaged portions121b,121bin symmetry by holding the center hole121dtherebetween, in between adjacent end portions in a circumferential end direction between the first engaged portions121b,121b.

The rotation plate122is formed to be a substantially rhombus shape. In one surface of the rotation plate122, two engaging portions (rotation plate engaging portions)122a,122aare provided in symmetrical positions holding the center therebetween. Two rotation plate engaging portions122a,122aare composed of columnar protrusions, are assembled in a direction in which the columnar protrusions protrude to the input plate121side, and are engaged to the second engaged portions121c,121cformed to be an arc shape, respectively. Since the rotation plate122is formed to be the substantially rhombus shape, the rotation plate122has four inclined side surfaces122b. In the center of the rotation plate122, a fitting hole122cthat is located at one end side of the output unit130and fits with a connection shaft part131in which a plurality of irregular parts protrude in an outer circumference, is formed by penetrating. Accordingly, when the rotation plate122rotates, the output unit130rotates.

The rotation plate122is installed in an inner circumference range in which the inner teeth124bof the internal gear124are formed. The outer diameter of the rotation plate122along a longer diagonal line (line shown by reference sign X inFIG. 6(b)) has a length that is shorter than the inner diameter of the internal gear124and does not contact with the inner teeth124bso that the rotation plate122can rotate in any direction. The internal gear124includes flange parts124a,124athat protrude to both sides. The attachment pieces112b,112bof the cover member112are stacked to the flange parts124a,124a, and the internal gear124is attached to an outer surface of one of the side frames31composing the cushion frame3by using a screw.

As shown inFIG. 6, the lock plates123are installed in spaces formed between each of four inclined side surfaces122bof the rotation plate122and the inner teeth124bformed in the inner circumference of the internal gear124. As shown inFIG. 6andFIG. 7, the lock plates123are formed in a shape that is approximate to a right triangle or a quarter circle in a plan view. A side of the shape corresponding to a hypotenuse of a right triangle is an arc part123ahaving an almost same curvature as the inner circumference of the internal gear124. A bottom surface part123bof the shape corresponding to a base of a right triangle contacts with each of the inclined side surfaces122bof the rotation plate122. That is, the inclined side surface122bof the rotation plate122and the bottom surface part123bof the lock plates123are contact surfaces that contact with each other. Since the rotation plate122is the substantially rhombus shape, inclined side surfaces122b,122bthat are adjacent by holding the longer diagonal line of the rotation plate122therebetween incline so that they gradually come close to each other as going from the center to outward. Accordingly, when the lock plates123,123arranged adjacently by holding the longer diagonal line of the rotation plate122therebetween are energized in a direction of contacting with the inclined side surfaces122b,122bto which the bottom surface parts123b,123bcorrespond, the inclined side surfaces122b,122bthat are adjacent by holding the longer diagonal line therebetween approach as going outward. Thereby, the lock plates123,123are guided along these inclined side surfaces122b,122band are pushed out radially outward.

In order to achieve this function, in a direction of contacting with the inclined side surfaces122b,122bthat are adjacent by holding the longer diagonal line therebetween, the third spring125and the fourth spring126that serve as spring members energizing the bottom surface parts123b,123bof the lock plates123,123are installed. Both of the third spring125and the fourth spring126are formed in a substantially circular shape, while they are bent at substantially 90 degrees so as to protrude in the same direction before end portions125a,125aoverlap each other and end portions126a,126aoverlap each other. The third spring125inserts the end portions125a,125afrom a surface located at the retainer114side in the input plate121via a through hole formed in the input plate121, and engages the end portions125a,125ato spring engagement holes123f,123fof the lock plates123,123of one set in which the bottom surface parts123b,123bare adjacent to each other in the circumferential direction by holding the longer diagonal line of the rotation plate122therebetween (the set of the first lock plate123and the fourth lock plate123). Similarly, the fourth spring126is engaged to the spring engagement holes123f,123fof the other set of two lock plates123,123(the set of the second lock plate123and the third lock plate123) from the opposite surface side of the lock plates123,123by the end portions126a,126a.

Both of the third spring125and the fourth spring126are provided so that each of the lock plates123,123in one set of a pair of two (each of the first lock plate123and the fourth lock plate123) and each of the lock plates123,123in the other set (each of the second lock plate123and the third lock plate123) in which the bottom surface parts123b,123bare adjacent to each other in the circumferential direction by holding the longer diagonal line of the rotation plate122therebetween are energized in a direction of approaching. By the third spring125and the fourth spring126, the bottom surface parts123b,123bof each of the lock plates123,123are always pushed to each of the inclined side surfaces122b,122bof the lock plates122. Thereby, each of the lock plates123,123is energized in a direction of releasing outward along the inclination of each of the inclined side surfaces122b,122b(radially outward). By providing the third spring125and the fourth spring126in this way, backlash between components including the rotation plate122, the lock plates123, and the internal gear124is reduced by the effect of the elastic force of the third spring125and the fourth spring126. The backlash between components is essential for smooth operation. Whereas, an abnormal sound is generated due to the backlash by effect of vibration or the like, during the travel. However, having the third spring125and the fourth spring126can secure smooth operation between components by their elasticity, while it can contribute to prevent the abnormal sound from being generated.

In an arc part123athat is an outer circumferential surface of the lock plates123, outer teeth123cthat engage with the inner teeth124of the internal gear124is formed. When the number of teeth of the outer teeth123cis larger, the internal gear124is easy to rotate by the input from the output side. On the other hand, when the number is too small, necessary strength cannot be acquired. Thus, setting is performed with consideration to this. The outer teeth123cis preferably formed in the vicinity of a corner portion between the arc part123aand the bottom surface part123bin order to prevent a pressure angle of the outer teeth123cfrom changing due to the rotation of the lock plates123by the input from the output side. However, depending on the length of the bottom side part123bof the lock plates123, the function of preventing rotation of the lock plates123is increased by the outer teeth123c. Thus, the outer teeth123cmay be formed in, for example, the vicinity of the center of the arc part123a.

The lock plates123are provided with, in one surface, in the vicinity of a corner portion between the bottom surface part123band an outside surface side part123dthat erects from the bottom surface part123bto the arc part123a, an engaging portion (lock plate engaging portion)123ecomposed of a columnar protrusion. The engaging portion123eis assembled in a direction in which the engaging portion123eprotrudes to the input plate121side. The lock plate engaging portion123eis engaged to the first engaged portions121bof the input plate121. As described above, in the present embodiment, each of the lock plate engaging portions123e,123eof two lock plates123,123in which the outside surface parts123d,123dare adjacent to each other in the circumferential direction (the set of the first lock plate123and the second lock plate123and the set of the third lock plate123and the fourth lock plate123) is arranged in one of the first engaged portions121b. Thus, an interval in a circumferential direction of each of the first engaged portions121b,121bis longer than an interval of adjacent two lock plate engaging portions123e,123ein the circumferential direction. Thereby, when the input plate121rotates in either forward or reverse direction, the lock plates123,123of a pair of two that face each other diagonally (when it is clockwise, the set of the first lock plate123and the third lock plate123and when it is counterclockwise, the set of the second lock plate123and the fourth lock plate123) among four lock plates contact with the lock plate engaging portions123e,123e. Thereby, a rear end surface in the rotation direction (as shown inFIG. 8, when the rotation direction by the input torque is clockwise, B surface) in the first engaged portions121b,121bin the first engaged portions121b,121bis towed in the rotation direction of the input plate121.

As shown inFIG. 8, an angle α between the rear end surface in the rotation direction of the first engaged portions121b,121bof the lock plates123,123of one set of a pair of two that face each other diagonally (the B surface (FIG. 8shows the B surface only for the lock plate123(first lock plate123) of one side among the lock plates123,123of one pair of two (the set of the first lock plate123and the third lock plate123. Only corresponding ones are shown also for A surface, C surface, and D surface below) of when the rotation direction is clockwise) and a surface (D surface) that contacts with the inner teeth124bin the outer teeth123c,123cthat are in a front side in the rotation direction of the clockwise in the lock plates123,123of the one set of a pair of two (the set of the first lock plate123and the third lock plate123) is made to be an acute angle. Moreover, the force of being pushed of the bottom surface parts123b,123bof the lock plates123,123to the inclined side surfaces122b,122b(A surface) of the rotation plate122by the third spring125and the fourth spring126is set larger than the friction force generated in the contact surface (B surface) of both of the rear end surface in the rotation direction and the lock plate engaging portions123e,123eby the force of pushing the lock plate engaging portions123e,123eby the rear end surface in the rotation direction (B surface) of the first engaged portions121b,121b. Thereby, when the lock plates123,123of one pair of two that face each other diagonally (the set of the first lock plate123and the third lock plate123) are towed in the rotation direction of the input plate121as described above, that is, when the rear end surface in the rotation direction (B surface) of the first engaged portions121b,121bpushes the lock plate engaging portions123e,123e, the bottom surface parts123b,123bof the lock plates123,123(the first lock plate123and the third lock plate123) slide on the inclined side surfaces122b,122b(A surface) of the rotation plate122. Thus, engagement between the outer teeth123c,123cand the inner teeth124bof the lock plates123,123of the one set of one pair of two that face each other diagonally (the set of the first lock plate123and the third lock plate123) is released.

The third spring125and the fourth spring126are set so that the spring force is applied to the reduced diameter direction in which the bottom surface parts123b,123bof the lock plates123,123(each of the first lock plate123and the fourth lock plate123, and each of the second lock plate123and the third lock plate123) are pushed to the corresponding inclined side surfaces122b,122b(A surface) in the rotation plate122. However, an angle β between a line along a direction of action of the spring force and a surface (C surface) that is a front side in the clockwise rotation direction in the lock plates123,123of the other set of a pair of two that face each other diagonally (the second lock plate123and the fourth lock plate123) and fits with the inner teeth124bin the outer teeth123c,123c, is set to be an acute angle. Thereby, when engagement between the outer teeth123c,123cand the inner teeth124bof the lock plates123,123of the one set of a pair of two that face each other diagonally (the first lock plate123and the third lock plate123) is released as described above according to the rotation of the input plate121, a rear end surface in the rotation direction of the second engaged portions121c,121cof the input plate121contacts to the rotation plate engaging portions122a,122ato rotate the rotation plate122in the same direction. When the rotation plate122rotates, the third spring125and the fourth spring126attempt to rotate, by the elastic force thereof, the lock plates123,123of the other set of a pair of two that face each other diagonally (the second lock plate123and the fourth lock plate123) in the same direction. At this time, the outer teeth123c,123cof the lock plates123,123of the other set of a pair of two (the second lock plate123and the fourth lock plate123) rotate while sliding on the engaged surface with the inner teeth124b(C surface) and their engagement is released. Thus, the lock-released state is established.

The rotation plate122starts to rotate by the rear end surface in the rotation direction of the second engaged portions121c,121cof the input plate121contacting to the rotation plate engaging portions122a,122a. Therefore, the relative positions of the input plate121and the rotation plate122are deviated for the amount of rotation. Thus, it is preferable that the fifth spring127is installed that imparts an elastic force to return the relative positions of the input plate121and the rotation plate122to the neutral position (the rotation plate engaging portions122a,122ato the center of the circumferential direction of the second engaged portions121b,121c) when imparting of the input torque is lost and the rotation of the input plate121is stopped. In the present embodiment, while the fifth spring127is formed to be a substantially circular shape, the fifth spring127is bent at substantially 90 degrees so as to protrude in the same direction before the end portions127a,127aoverlap each other. The fifth spring127is formed to have a smaller diameter than that of the third spring125. From a surface located at the retainer114side in the input plate121, the end portions127a,127aare inserted via a through hole formed in the input plate121. The end portions127a,127aare engaged with the spring engagement holes122d,122cformed in the rotation plate122. At this time, the fifth spring127is reduced in its diameter to engage with the spring engagement holes122d,122dand is installed so that the elastic force acts in the increased diameter direction. Thereby, deviation of the relative positions of the input plate121and the rotation plate122is released soon after the input torque is lost, and the relative positions return to the neutral position.

On the other hand, an angle γ between the inclined side surfaces122b(A surface) of the rotation plate122that is a contact surface of the bottom surface parts123bof each of the lock plates123and a surface (D surface) that contacts with the inner teeth124bin the outer teeth123cof each of the lock plates123, is set smaller than a frictional angle γMAX(the maximum value of an angle with which the lock plates123do not slide even when being pushed by the rotation plate122). Therefore, even when each of the lock plates123is pushed by the rotation plate122, engagement between the outer teeth123cand the inner teeth124bis not released. That is, when a torque is input from the output unit130, the rotation plate122is attempted to rotate. However, even when the lock plates123are pushed in the rotation direction in order to rotate the rotation plate122, engagement between the outer teeth123cand the inner teeth124bis not released and thereby, torque is not transferred.

As described above, the output unit130is formed with, in one end side, the connection shaft part131of which a plurality of irregular parts protrude in an outer circumference. The fitting hole122cof the rotation plate122formed in a shape fitting to the connection shaft part131, is installed by being fitted to the connection shaft part131. In the other end side of the output unit130, for example, a gear part132is provided. The gear part132is installed so as to protrude to an outer surface124cthat is the opposite side from the surface in which the rotation plate122and the lock plates123are accommodated, in the internal gear124. The gear part132is engaged to a control target member, for example, a gear mechanism23in the lifter mechanism2.

It is preferable that the sixth spring128formed of a belleville spring is installed as the other spring member between the output unit130and the outer surface124cof the internal gear124. Thereby, in the rotation control unit120including the output unit130and the internal gear124, elasticity acts in the direction of separating from each other and backlash between the output unit130and the internal gear124is absorbed. Moreover, reverse of the output unit130due to the input from the output side is prevented during the transfer with the transfer mechanism110by friction of the sixth spring128.

Next, effect of the present embodiment will be described. In the present embodiment, the torque transfer control mechanism1is incorporated to the lifter mechanism2. Thus, in order to move the cushion frame3vertically, the lever111of the transfer mechanism110is rotated in either forward or reverse direction, first. Thereby, the shaft113rotates in the same direction to rotate the cam115in the same direction. When the cam115rotates in the same direction, a state shown inFIG. 5(a)is changed to a state shown inFIG. 5(b)and any of the inclined side surfaces115bpushes the rollers116radially outward. The roller116is pushed radially outward, the input plate121of the rotation control unit120is rotated and the retainer114is rotated in the same direction. When the retainer114rotates, the retainer protruding piece114cstarts to separate gradually in the rotation direction from the cover protruding piece112c, and rotates until the retainer protruding piece114ccontacts to any of the cutout end surfaces112a1or112a2of the cover member112by one-time operation of the lever111(seeFIG. 5(d)).

When the transfer mechanism110is rotated in either forward or reverse direction, in this way, the input plate121of the rotation control unit120rotates. When the input plate121rotates, for example, in the clockwise direction ofFIG. 6, the lock plate engaging portions123a,123aof the lock plates123,123of the one set of a pair of two that face each other diagonally (the first and third lock plates123,123) is pushed to the rear end surface in the rotation direction of the first engaged portions121b,121bof the input plate121. Then, the state ofFIG. 6(b)is changed to the state ofFIG. 6(c), and the outer teeth123c,123cof the lock plates123,123of the one set of a pair of two (the first and third lock plates123,123) are released from the inner teeth124b. When the input plate121continues to rotate, the state changes from that ofFIG. 6(c)to that ofFIG. 6(d), the rear end surface in the rotation direction of the second engaged portions121c,121cof the input plate121contact to the rotation plate engaging portions122a,122aand the rotation plate122rotates in the same direction. When the rotation plate122rotates, by the elastic force in the reduced diameter direction of the third spring125and the fourth spring126, the lock plates123,123of the other set of a pair of two that face each other diagonally (the second and fourth lock plates123,123) are attempted to rotate in the same direction, and the outer teeth123c,123cof the lock plates123,123of the other set of a pair of two (the second and fourth lock plates123,123) slide on the surface (C surface) of engagement with the inner teeth124bwhile rotating, and thereby engagement between the outer teeth123c,123cand the inner teeth124bis released.

Then, the output unit130that is engaging with the connection shaft part131to the fitting hole122cof the rotation plate122rotates to rotate the gear mechanism23of the lifter mechanism2that is engaging with the gear part132. By rotation of the gear mechanism23, the cushion frame3displaces in either upward or downward direction. As shown inFIG. 5(d), by one transfer operation by the transfer mechanism110, the retainer protrusion piece114crotates until the retainer protrusion piece114ccontacts to either of the cutout end surfaces112a1or112a2of the cover member112. However, by that one operation, the positional relationship of the first engaged portions121b,121bof the input plate121, the rotation plate122, and the lock plates123changes from the position shown inFIG. 6(a)to that shown inFIG. 6(e).

During this, in the transfer mechanism110, the force is applied in the direction of reducing the diameter of the second spring118according to the movement of the lever111in the direction described above. When the cushion frame3is displaced to a predetermined position, the operation of the lever111is stopped. When application of the input torque that makes the lever111operated is lost, the second spring118returns and attempts to increase its diameter. By the force, the retainer114returns to the neutral position in which the retainer protruding piece114coverlaps the cover protruding piece112cof the cover member112, that is, from the position ofFIG. 5(d)to the position ofFIG. 5(a). Accordingly, the lever111also returns to the neutral position. When the input torque is lost, by the elastic force of the first spring117, the position of the cam115with respect to the retainer114also returns to the neutral position as described above. In this state, when the lever111is rotation operated again in either forward or reverse direction, the cushion frame3is displaced in either upward or downward direction as described above via the rotation control unit120and the output unit130.

On the other hand, when application of the input torque that makes the lever111operated is lost, in the rotation control unit120, the torque of the input plate121that operates the lock plates123,123is lost. Thus, the lock plates123,123are energized in the direction in which the bottom surface parts123b,123bare pushed to the inclined side surfaces122b,122bof the rotation plate122by the elastic force of the third spring124and the fourth spring125. Then, since the rotation plate122is formed to be a substantially rhombus shape that is a tapered shape of which width narrows as going outward, the rotation plate122is displaced radially outward along the inclined side surfaces122b,122b, each of the outer teeth123c,123cengages with the inner teeth124bto become the locked state, and the rotation plate122and the lock plates123,123are maintained in a state of being rotated at a predetermined angle from the position before operation (seeFIG. 6(e)). When operation of the lever111in either forward or reverse direction in the transfer mechanism110is repeated intermittently and a state where the input torque is not applied is established, the lifter mechanism2adjusts the cushion frame3to a predetermined height.

In the locked state where the input torque is not applied and each of the outer teeth123c,123cof the lock plates123,123engages with the inner teeth124bas described above, when input is performed from the cushion frame3side via the output unit130, the rotation plate122connected to the output unit130attempts to rotate. However, in this case, the rotation plate122cannot rotate as described above and engagement between the outer teeth123c,123cand the inner teeth124bis not released. That is, a load from the cushion frame3side is a force to rotate the output unit130, and when the output unit130attempts to rotate, the rotation plate122fitted with the connection shaft part131attempts to rotate next. However, even when the rotation plate122attempts to rotate and pushes each of the lock plates123,123in the rotation direction, because of the angular setting as described above, engagement of the outer teeth123c,123cof the lock plates123,123with respect to the inner teeth124bis not released. Thereby, in the present embodiment, there is no displacement such as the height of the cushion frame3being reduced gradually, unlike the conventional one. When, instead of the manual lever111, a motor (not shown) is connected to the base part111aand an electric operation mechanism is configured so that the base part111arotates in the forward and reverse directions electrically, even when the output unit130attempts to rotate, the locked state described above by the lock plates123is maintained. Thus, such configuration reduces a burden on the motor and can contribute to the breakage prevention of the motor.

In the present embodiment, for example, when rotation is performed in clockwise ofFIG. 6, the lock plates123,123of the one set of a pair of two that face each other diagonally (the first and third lock plates123,123) move synchronously. After that, by the elastic force in the reduced diameter direction of the third spring125and the fourth spring126, the lock plates123,123of the other set of a pair of two that face each other diagonally (the second and fourth lock plates123,123) move synchronously. That is, while four lock plates123are used, two plates move synchronously, and thereby similar smooth movement to the one in a configuration of two lock plates can be secured.

The present invention is not limited to the embodiment described above. For example, in the embodiment described above, in the cushion frame3, only in one side frame31, the rotation movement control mechanism1incorporated to the lifter mechanism2is installed. However, as shown inFIG. 9, it may be configured so that, while similar rotation movement control mechanism1to the one described above is installed in one side frame31of the cushion frame3, the other side frame31is installed with a structure that excludes the transfer mechanism110and includes the rotation control unit120and the output unit130. In this case, since the transfer mechanism110is provided only in one side, in order to synchronize right and left, a right and left connection rod140is bridged between the right and left output units130,130. Thereby, when the transfer mechanism110located at one side is operated, the right and left rotation control units120synchronize and move. Thus, a load applied per each of the rotation control units120can be reduced and load resistant strength can be set higher than the configuration in which the mechanism is disposed only in one side.

FIG. 10illustrates examples of when the rotation movement control mechanism1described above is disposed as a reclining adjuster1000in a boundary between the cushion frame3and the back frame6, and when the rotation movement control mechanism1described above is disposed as a lumbar adjuster2000that can move a lumbar support2100to front and back, in a side frame61of the back frame6. As shown inFIG. 10, the rotation movement control mechanism1may be disposed in both of the reclining adjuster1000and the lumbar adjuster2000. In addition to that, the rotation movement control mechanism1may be concurrently used as the lifter mechanism of the embodiment described above, and also, may be used in at least any one position thereof.

EXPLANATION OF REFERENCES