Linkage mechanism, pressing device provided with the same and seat device provided with the same

Abstract

To transmit power from a first linkage to a second linkage regardless of an angle which determines between the first linkage and the second linkage.SOLUTION: A linkage mechanism (30) comprises a guide member (31), a first stationary gear (311) which is incapable of relatively rotating to the guide member (31), a first linkage (32) which pivotally supports so as to make it possible to relatively rotate a first intermediate gear (322) which meshes with the first stationary gear (311) and turns against the guide member (31) by transmission of driving force and a second linkage (33) which there is fixed the second stationary gear (331) which rotates in a direction opposed to a turning direction of the first linkage (32) by meshing with the first intermediate gear (322) and turns against the first linkage (32) in a direction opposed to a turning direction of the first linkage (32) along with the rotation of the second stationary gear (331).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a link mechanism, a pressing device including the link mechanism, and a seat device including the link mechanism. [Background technology]

[0002] Patent Document 1 describes a vehicle seat device that is equipped with a lumbar support mechanism that changes the amount of protrusion of the receiving surface of the seat back that corresponds to the lumbar region of the seated person, and further employs a massage mechanism having an acupressure roller for applying localized stimulation to the lumbar region of the seated person.

[0003] The massage mechanism has a link member having a connecting member connected to one end in the longitudinal direction. The link member rotates about the rod as the connecting member moves. When the link member rotates, the finger pressure roller moves forward of the seat device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-153765 A Summary of the Invention [Problem to be solved by the invention]

[0005] The link member of the massage mechanism described in Patent Document 1 rotates around the rod when a driving force is transmitted from the connecting member. However, when the angle between the connecting member and the link member approaches 0°, it becomes difficult for the driving force to be transmitted from the connecting member to the link member. Therefore, when the angle between the connecting member and the link member approaches 0°, it may become difficult for the link member to rotate relative to the connecting member.

[0006] One aspect of the present disclosure aims to transmit power from a first link to a second link regardless of the angle between the first link and the second link. [Means for solving the problem]

[0007] In order to solve the above problems, a link mechanism according to one embodiment of the present disclosure includes a first member, a first gear that cannot rotate relative to the first member, a first link that supports an intermediate gear that meshes with the first gear so as to be rotatable relative to the first member and rotates relative to the first member upon transmission of a driving force, and a second gear that rotates in a direction opposite to the rotation direction of the first link by meshing with the intermediate gear and is fixed, and which rotates relative to the first link in the direction opposite to the rotation direction of the first link as the second gear rotates. Effect of the Invention

[0008] According to one aspect of the present disclosure, power can be transmitted from the first link to the second link regardless of the angle between the first link and the second link. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an overview of a seat device including a link mechanism according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram illustrating the configuration of the headrest shown in FIG. [Diagram 3] 2 is a front perspective view of a pressing device included in the seat device; FIG. [Figure 4] 2 is a perspective view of a pressing device included in the seat device, as viewed from the rear. FIG. [Diagram 5] FIG. 4 is a side view showing the configuration of the link mechanism. [Figure 6] 11A and 11B are diagrams for explaining the operation of a link mechanism. [Figure 7] 11 is a schematic diagram showing a configuration of a link mechanism according to a second embodiment of the present disclosure. FIG. [Figure 8] 8 is a schematic diagram of the link mechanism shown in FIG. 7 as viewed in the direction of arrow X. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment 1] Hereinafter, one embodiment of the present disclosure will be described in detail.

[0011] A seat device 1 including a link mechanism 30 according to the first embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a schematic diagram for explaining an overview of the seat device 1 including the link mechanism 30. Fig. 2 is a schematic diagram for explaining the configuration of the headrest 3 shown in Fig. 1. For convenience of explanation, the up-down direction, the front-rear direction, and the left-right direction are defined as shown by the arrows in Fig. 1 etc. The front-rear direction and the left-right direction are directions based on a user seated in a normal manner. The left-right direction corresponds to the width direction of the seat device 1.

[0012] The seat device 1 according to the first embodiment includes a seat cushion (not shown) and a seat back 2. The seat back 2 is attached to the seat cushion and is reclining relative to the seat cushion. As shown in FIG. 1, the seat back 2 is provided with a headrest 3. The headrest 3 is provided on the front side of the seat back 2, at a position corresponding to the head and shoulders of a seated user U. The width W1 of the headrest 3 in the front-rear direction is about 40 mm to 80 mm. As an example, the width W1 is 60 mm.

[0013] As shown in FIG. 2, a pressing unit 4 is provided below the headrest 3. The pressing unit 4 is provided at a position corresponding to the shoulders of a seated user U. A pressing device 100 including a pressing member 40, which will be described later, is disposed in the pressing unit 4. The pressing device 100 is a device that moves the pressing member 40 in the front-rear direction and / or the left-right direction. The pressing member 40 of the pressing device 100 presses forward a cushion material attached to the headrest 3. As the pressing member 40 of the pressing device 100 moves forward, it presses the shoulders of the user U from the back side of the user U.

[0014] A detailed configuration of the pressing device 100 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a perspective view of the pressing device 100 provided in the seat device 1, seen from the front. Fig. 4 is a perspective view of the pressing device 100 provided in the seat device 1, seen from the rear. The pressing device 100 shown in Figs. 3 and 4 is a device that presses the left shoulder of a seated user. Note that in Figs. 3 and 4, the pressing device that presses the right shoulder of a user is not shown because it has the same configuration as the pressing device 100 that presses the left shoulder of a user.

[0015] As shown in FIG. 3, the pressing device 100 includes a frame 11, a moving mechanism 10, a driving force transmission mechanism 20, a link mechanism 30, and a pressing member 40. The frame 11 is fixed to the seat device 1. The frame 11 is composed of a first frame 111, a second frame 112, and a third frame 113. The first frame 111 is a frame whose longitudinal direction is the left-right direction. The second frame 112 is a frame that extends downward from the right end of the first frame 111. The third frame 113 is a frame that extends downward from the left end of the first frame 111. The moving mechanism 10 and the driving force transmission mechanism 20 are supported by the frame 11.

[0016] The movement mechanism 10 is a mechanism for moving the link mechanism 30 in the left-right direction. That is, the movement mechanism 10 moves the link mechanism 30 in the width direction of the seat device 1. The movement mechanism 10 has a first drive motor (not shown), a first bevel gear 13, a second bevel gear 14, a first shaft 15, and a movable member 16. The first drive motor is supported by a bracket 12 attached to a second frame 112. The first drive motor may provide a driving force to the movement mechanism 10 of the pressing device 100 that presses the right shoulder of the user.

[0017] The rotating shaft of the first drive motor is connected to the center of rotation of a first bevel gear 13. The first bevel gear 13 is rotatably supported by a bracket 12. When the rotating shaft of the first drive motor rotates, the first bevel gear 13 rotates. A second bevel gear 14 meshes with the first bevel gear 13. The second bevel gear 14 is rotatably supported by a second frame 112. When the first bevel gear 13 rotates, the second bevel gear 14 rotates.

[0018] A first shaft 15 having a male thread formed on its outer circumferential surface is connected to the second bevel gear 14. The first shaft 15 is a shaft extending in the left-right direction. A right end of the first shaft 15 is rotatably supported by the third frame 113. The first shaft 15 rotates together with the rotation of the second bevel gear 14.

[0019] A movable member 16 having a female thread that screws into the male thread of the first shaft 15 is attached to the first shaft 15. A guide shoe 18 that engages with a guide 17 formed below the first frame 111 is attached above the movable member 16. The guide 17 is formed approximately parallel to the first shaft 15. The movable member 16 moves along the axial direction of the first shaft 15 indicated by the arrow D1 as the first shaft 15 rotates, and is guided by the guide 17 in the axial direction of the first shaft 15 indicated by the arrow D1. That is, the movable member 16 moves in the left-right direction.

[0020] As shown in Fig. 4, a bracket 19 is attached to the rear of the movable member 16. A link mechanism 30, which will be described later, is attached below the bracket 19. When the movable member 16 moves in the direction D1 shown in Fig. 3, the link mechanism 30 also moves in the direction D1. As the link mechanism 30 moves in the direction D1, the pressing member 40 also moves in the direction D1. That is, the link mechanism 30 and the pressing member 40 move in the left-right direction together with the movement of the movable member 16.

[0021] The driving force transmission mechanism 20 is a mechanism that transmits a driving force to the link mechanism 30. The driving force transmission mechanism 20 has a second driving motor (not shown), a sector gear 21, an arm 22, a driven gear 23, a second shaft 24, and an input gear 25. As shown in FIG. 4, the second driving motor is supported by a second frame 112. The second driving motor is an example of a driving unit. The second driving motor may apply a driving force to the driving force transmission mechanism 20 of the pressing device 100 that presses the right shoulder of the user.

[0022] The rotary shaft of the second drive motor is connected to a rotary shaft 211 of the sector gear 21. The sector gear 21 is supported by the second frame 112. The sector gear 21 rotates about the rotary shaft 211 as the rotary shaft of the second drive motor rotates.

[0023] The arm 22 rotates around a rotation shaft 221 supported by the second frame. A gear 222 that meshes with the sector gear 21 is formed at one end of the arm 22 in the longitudinal direction. The arm 22 rotates around the rotation shaft 221 as the sector gear 21 rotates. A gear (not shown) that meshes with the driven gear 23 is formed at the other end of the arm 22 in the longitudinal direction. As shown in FIG. 3, the driven gear 23 is supported by the second frame 112. The driven gear 23 rotates as the arm 22 rotates.

[0024] A second shaft 24 is connected to the driven gear 23. The second shaft 24 is a polygonal prism-shaped shaft extending in the left-right direction. The left end of the second shaft 24 is rotatably supported by the second frame 112, and the right end is rotatably supported by the third frame 113. The second shaft 24 rotates as the driven gear 23 rotates.

[0025] The second shaft 24 is fitted into the center hole of the input gear 25. The input gear 25 rotates in accordance with the rotation of the second shaft 24. The input gear 25 is slidable relative to the second shaft 24 in the axial direction of the second shaft. The input gear 25 moves left and right in accordance with the left and right movement of the link mechanism 30, and slides relative to the second shaft 24.

[0026] The input gear 25 is connected to the link mechanism 30 and transmits the driving force from the second drive motor to the link mechanism 30. When the driving force is transmitted to the link mechanism 30, the pressing member 40 attached to the link mechanism 30 moves in the direction indicated by the arrow D2. That is, the pressing member 40 moves in the front-rear direction of the seat device 1. More specifically, the pressing member 40 moves forward and downward, or rearward and upward.

[0027] <Link mechanism> The link mechanism 30 will be described in detail with reference to Fig. 5. Fig. 5 is a side view showing the configuration of the link mechanism 30. The link mechanism 30 has a guide member 31, a first link 32, a second link 33, and a slide member 34.

[0028] The guide member 31 is fixed to the bracket 19 of the moving mechanism 10. The guide member 31 is an example of a first member. The first fixed gear 311 is formed integrally with the guide member 31. The first fixed gear 311 is an example of a first gear. The first fixed gear 311 is a gear that cannot rotate relatively to the guide member 31. This makes it possible to reduce the number of parts.

[0029] It should be noted that the first fixed gear 311 is not limited to being formed integrally with the guide member 31. The first fixed gear 311 may be any gear that is fixed to the guide member 31 so as not to rotate relative to the guide member 31. Also, although the first fixed gear 311 is fixed to the guide member 31, the first fixed gear 311 is not limited to this configuration. It may be a gear that is fixed to a member different from the guide member 31 and is not rotatable relative to the guide member 31.

[0030] The first link 32 is a link that rotates relative to the guide member 31 by the transmission of the driving force. One end side of the first link 32 in the longitudinal direction is attached to the guide member 31. The first link 32 rotates relative to the guide member 31 around a first rotating shaft 35 supported by the guide member 31. A sector gear 321 that meshes with the input gear 25 is integrally formed at one end of the first link 32 in the longitudinal direction. The sector gear 321 is an example of a third gear. By integrally forming the sector gear 321 with the first link 32, the number of parts can be reduced. The driving force from the second drive motor is transmitted from the input gear 25 to the sector gear 321, so that the first link 32 rotates relative to the guide member 31. The sector gear 321 is not limited to a configuration that is integrally formed with the first link 32. It is sufficient that a gear that meshes with the input gear 25 and cannot rotate relatively is fixed to the first link 32.

[0031] The first link 32 supports a first intermediate gear 322 meshing with the first fixed gear 311 at a central portion in the longitudinal direction of the first link 32. The first intermediate gear 322 is rotatable relative to the first link 32 about a rotation shaft 323 supported by the first link 32. In the first embodiment, one first intermediate gear 322 is supported by the first link 32, but the present invention is not limited to this configuration. An odd number of first intermediate gears 322 may be supported by the first link 32. The radius of the first intermediate gear 322 is substantially the same as the radius of the first fixed gear 311.

[0032] The second link 33 is attached to the other end of the first link 32 in the longitudinal direction. The second link 33 rotates relative to the first link 32 around a second rotating shaft 36 supported by the first link 32. Here, the angle between the first link 32 and the second link 33 is defined as angle θ. The angle θ corresponds to an acute angle between a line connecting the first rotating shaft 35 and the second rotating shaft 36 and a line connecting the second rotating shaft 36 and the third rotating shaft 37. When the second link 33 rotates relative to the first link 32, the angle θ changes.

[0033] The second fixed gear 331, which meshes with the first intermediate gear 322, is formed integrally with the second link 33. The second fixed gear 331 is an example of a second gear. Since the second fixed gear 331 is formed integrally with the second link 33, the number of parts can be reduced. The radius of the second fixed gear 331 is substantially the same as the radius of the first fixed gear 311, and the outer diameter of the second fixed gear 331 is substantially the same as the outer diameter of the first intermediate gear 322. Note that the second fixed gear 331 is not limited to being formed integrally with the second link 33. The second fixed gear 331 may be any gear that meshes with the first intermediate gear 322 and is fixed to the second link 33 so as not to rotate relative to the second link 33.

[0034] The rotation axis of the second fixed gear 331 is coaxial with the second rotating shaft 36. The slide member 34 is attached to the other end side in the longitudinal direction of the second link 33. The second link 33 rotates relative to the slide member 34 about a third rotating shaft 37 supported by the slide member 34. A length L1 in the longitudinal direction of the first link from the first rotating shaft 35 to the second rotating shaft 36 is equal to a length L2 in the longitudinal direction of the second link 33 from the second rotating shaft 36 to the third rotating shaft 37.

[0035] The slide member 34 engages with the guide member 31. The slide member 34 is an example of a second member. When viewed from the side, the length of the slide member 34 in the longitudinal direction is substantially the same as the length of the guide member 31 in the longitudinal direction. The longitudinal direction of the slide member 34 is the same as the longitudinal direction of the guide member 31. The length of the slide member 34 in the longitudinal direction may be longer or shorter than the length of the guide member 31 in the longitudinal direction.

[0036] The slide member 34 slides relative to the guide member 31 as the second link 33 rotates relative to the first link 32. The slide member 34 slides along the longitudinal direction of the guide member 31 as indicated by arrow D3. A pressing member 40 is attached to the slide member 34. As the slide member 34 slides, the pressing member 40 moves in the front-rear direction of the seat device 1.

[0037] <Operation of the link mechanism> Next, the operation of the link mechanism 30 will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining the operation of the link mechanism 30.

[0038] Reference numeral 1000 in Fig. 6 illustrates the link mechanism 30 when the slide member 34 is positioned at the rearmost position. As illustrated by reference numeral 1000 in Fig. 6, when the slide member 34 is positioned at the rearmost position, the slide member 34 is stored in the guide member 31. At this time, the angle θ1 between the first link 32 and the second link 33 is close to 90°.

[0039] Here, the cases where the angle between the first link 32 and the second link 33 is positive and the cases where the angle between the first link 32 and the second link 33 is negative are defined as follows. When the second link 33 is located behind the first link 32, that is, when the third rotating shaft 37 is located behind and above the first rotating shaft 35, the angle between the first link 32 and the second link 33 is in a positive range. When the second link 33 is located ahead of the first link 32, that is, when the third rotating shaft 37 is located ahead of and below the first rotating shaft 35, the angle between the first link 32 and the second link 33 is in a negative range. The angle θ1 indicated by the reference symbol 1000 in FIG. 6 is in a positive range.

[0040] When the second drive motor is driven in the forward direction, the input gear 25 rotates in the direction indicated by the arrow D4. Hereinafter, the direction indicated by the arrow D4 is referred to as the D4 direction. The D4 direction is a counterclockwise direction. When the driving force is transmitted to the sector gear 321 of the first link 32 via the input gear 25, the first link 32 rotates around the first rotating shaft 35 relative to the guide member 31 as the sector gear 321 rotates. At this time, the first link 32 rotates in the direction indicated by the arrow D5. Hereinafter, the direction indicated by the arrow D5 is referred to as the D5 direction. The D5 direction is a clockwise direction, which is the opposite direction to the D4 direction. As the first link 32 rotates in the D5 direction, the second link 33 moves in the direction indicated by the arrow D31. That is, as the first link 32 rotates in the D5 direction, the second link 33 moves forward. Hereinafter, the direction indicated by the arrow D31 is referred to as the D31 direction.

[0041] The first intermediate gear 322 is journaled on the first link 32, and therefore moves in the D5 direction together with the rotation of the first link 32 in the D5 direction. When the first intermediate gear 322 moves in the D5 direction, the first intermediate gear 322 rotates about the rotation shaft 323 because it is engaged with the first fixed gear 311. The rotation direction of the first intermediate gear 322 at this time is the same as the rotation direction of the first link 32. That is, the first intermediate gear 322 rotates in the D5 direction.

[0042] As the first intermediate gear 322 rotates in the D5 direction, the second fixed gear 331 meshing with the first intermediate gear 322 rotates. At this time, the rotation direction of the second fixed gear 331 is opposite to the rotation direction of the first intermediate gear 322. That is, the second fixed gear 331 rotates in the D4 direction. As the second fixed gear 331 rotates in the D4 direction, the second link 33 rotates around the second rotating shaft 36 relative to the first link 32. The rotation direction of the second link 33 is the same as the rotation direction of the second fixed gear 331. That is, the second link 33 rotates in the D4 direction. The rotation direction of the second link 33 is opposite to the rotation direction of the first link 32.

[0043] As the second link 33 moves in the D31 direction and rotates in the D4 direction, the slide member 34 attached to the second link 33 slides in the D31 direction relative to the guide member 31. That is, the slide member 34 slides forward relative to the guide member 31. As the slide member 34 slides forward, the pressing member 40 located at the rearmost position moves forward.

[0044] Reference numeral 1001 in Fig. 6 shows a state in which the first link 32 rotates in the direction D4 relative to the guide member 31, and the slide member 34 moves in the direction D31 from the position shown by reference numeral 1000 in Fig. 6. The first link 32 moves to a position substantially perpendicular to the guide member 31. At this time, the angle between the first link 32 and the second link 33 is 0°. When the angle between the first link 32 and the second link 33 becomes 0°, there is a possibility that the propulsive force of the second link 33 in the direction of arrow D31 caused by the rotation of the first link 32 in the direction D5 will not act.

[0045] However, as described above, the second link 33 rotates relative to the first link 32 in accordance with the rotation of the second fixed gear 331 to which the driving force is transmitted from the first intermediate gear 322. Therefore, even if the angle between the first link 32 and the second link 33 becomes 0°, the second link 33 can continue to rotate in the D5 direction in accordance with the rotation of the first link 32 in the D4 direction. The guide member 31 slides in the D31 direction relative to the guide member 31 without losing the propulsive force in the D31 direction. In addition, since the second fixed gear 331 is fixed to the second link, the driving force transmitted from the first intermediate gear 322 can be transmitted to the second link 33 without being lost.

[0046] Here, when the link mechanism 30 is laid on its side, the width of the link mechanism 30 in a direction perpendicular to the longitudinal direction of the guide member 31 is defined as width W2. More specifically, the width W2 is the range from the front surface of the guide member 31 to the rear end of the first link 32 or the rear end of the second link 33, whichever is located furthest to the rear. The width W2 varies depending on the angle between the first link 32 and the second link 33. When the angle between the first link 32 and the second link 33 is 0°, the width W2 of the link mechanism 30 is maximum. On the other hand, the larger the angle between the first link 32 and the second link 33, the smaller the width W2 of the link mechanism 30 becomes.

[0047] Reference numeral 1002 in FIG. 6 indicates a state in which the first link 32 further rotates in the D4 direction and the slide member 34 further moves in the D31 direction from the position indicated by reference numeral 1001 in FIG. 6. With the further rotation of the first link 32 in the D5 direction, the second link 33 moves in the D31 direction and further rotates in the D4 direction relative to the first link 32. With the movement of the second link 33 in the D31 direction and the rotation of the second link 33 in the D4 direction, the slide member 34 further slides in the D31 direction relative to the guide member 31. The position of the slide member 34 indicated by reference numeral 1002 in FIG. 6 is a state in which the slide member 34 is located at the most forward position. At this time, the angle θ2 between the first link 32 and the second link 33 is in a negative range.

[0048] As shown in FIG. 6, the second link 33 passes through a position where the angle between the first link 32 and the second link 33 is 0°, and rotates between a range where the angle between the first link 32 and the second link 33 is positive and a range where the angle between the first link 32 and the second link 33 is negative.

[0049] According to the above configuration, the second link 33 rotates in accordance with the rotation of the second fixed gear 331 meshing with the first intermediate gear 322. Therefore, even if the angle between the first link 32 and the second link 33 becomes 0°, the second link 33 can continue to rotate in accordance with the rotation of the first link 32. This makes it possible to transmit power from the first link 32 to the second link 33 regardless of the angle between the first link 32 and the second link 33.

[0050] Furthermore, in the case of a link mechanism having two links that does not have a first intermediate gear 322, it is designed not to pass through a position where the relative angle between the two links is 0°. Therefore, the length of the link in the longitudinal direction becomes long. However, according to the link mechanism 30 of the present disclosure, the second link 33 rotates relative to the first link 32 through a position where the angle between the first link 32 and the second link 33 is 0°. With this configuration, the length L1 of the first link 32 and the length L2 of the second link can be shortened. This allows the maximum width W2 of the link mechanism 30 to be reduced.

[0051] [Embodiment 2] Another embodiment of the present disclosure will be described below with reference to Fig. 7 and Fig. 8. Fig. 7 is a schematic diagram showing a configuration of a link mechanism 30A according to a second embodiment. Fig. 8 is a schematic diagram of the link mechanism 30A shown in Fig. 7 as viewed from the direction of the arrow X. In Fig. 8, the first member 31A and the second member 34A are omitted from the illustration in consideration of ease of viewing the drawing.

[0052] For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the explanations thereof will not be repeated. Link mechanism 30A according to embodiment 2 differs from link mechanism 30 according to embodiment 1 in that it includes a third link 38.

[0053] As shown in Fig. 7, the first link 32A is attached to the first member 31A. The first link 32A has a third fixed gear 324. The third fixed gear 324 is not rotatable relative to the first link 32A and is formed integrally with the first link 32A. The third fixed gear 324 is centered around the second rotating shaft 36. As shown in Fig. 8, the third fixed gear 324 is formed on the surface of the first link 32A opposite to the surface facing the second link 33A.

[0054] As shown in Fig. 7, the second link 33A supports a second intermediate gear 332 that meshes with the third fixed gear 324 of the first link 32A. The second intermediate gear 332 is rotatable relative to the second link 33A around a rotation shaft 333 supported by the second link 33A. In the second embodiment, one second intermediate gear 332 is supported by the second link 33A, but the present invention is not limited to this configuration. An odd number of second intermediate gears 332 may be supported by the second link 33A.

[0055] A third link 38 is attached to the second link 33A. The third link 38 rotates relative to the second link 33A around a third rotating shaft 37A supported by the second link 33A. The second link 33A is attached to one end of the third link 38 in the longitudinal direction, and the second member 34A is attached to the other end of the third link 38 in the longitudinal direction. The third link 38 rotates relative to the second member 34A around a fourth rotating shaft 39 supported by the second member 34A. A fourth fixed gear 381 is fixed to one end of the third link 38 in the longitudinal direction. The fourth fixed gear 381 cannot rotate relative to the third link 38 and is formed integrally with the third link 38. The fourth fixed gear 381 rotates around the third rotating shaft 37.

[0056] The longitudinal length L1 of the first link from the first rotating shaft 35 to the second rotating shaft 36, the longitudinal length L2 of the second link 33 from the second rotating shaft 36 to the third rotating shaft 37A, and the longitudinal length L3 of the third link 38 from the third rotating shaft 37A to the fourth rotating shaft 39 are equal in length.

[0057] The operation of the link mechanism 30A will be described. When a driving force is transmitted to the first link 32A via the sector gear 321, the first link 32A rotates relative to the first member 31A. The rotation of the first link 32A causes the second link 33A to rotate. When the second link 33A rotates relative to the first link 32A, the second intermediate gear 332 of the second link 33A, which meshes with the third fixed gear 324 of the first link 32A, rotates in the same direction as the rotation direction of the second link 33A.

[0058] The third link 38 moves in the direction indicated by the arrow D6 in association with the rotation of the second link 33A. Furthermore, when the second intermediate gear 332 rotates, the fourth fixed gear 381 meshing with the second intermediate gear 332 rotates in a direction opposite to the rotation direction of the second intermediate gear 332. In association with the rotation of the fourth fixed gear 381, the third link 38 rotates about the third rotation shaft 37 relative to the second link 33A. When the third link 38 rotates relative to the second link 33A, the third link 38 rotates about the fourth rotation shaft 39 relative to the second member 34A, and the second member 34A moves in the direction indicated by the arrow D6 relative to the first member 31A.

[0059] Other embodiments In the above-described embodiment, the pressing device 100 is disposed in the headrest 3, but the present invention is not limited to such a configuration. The pressing device 100 may be disposed in the seat back 2. For example, the pressing device 100 may be disposed in a position corresponding to the lower back of a seated user U. The pressing device 100 may be configured to function as a lumbar support.

[0060] In the above-described embodiment, the first link 32 is configured to rotate relative to the guide member 31 by transmitting a driving force via a gear, but the present invention is not limited to such a configuration. As one example, the first link 32 may be configured to rotate relative to the guide member 31 by pressing or pulling one end of the first link 32 in the longitudinal direction.

[0061] In the above-described embodiment, the first fixed gear 311 that meshes with the first intermediate gear 322 is fixed to the guide member 31, but the present invention is not limited to such a configuration. The first intermediate gear 322 may mesh with a gear that is fixed to a member different from the guide member 31 and cannot rotate relatively to the guide member 31.

[0062] In the above-described embodiment, the radii of the first fixed gear 311, the first intermediate gear 322, and the second fixed gear 331 are substantially the same, but this is not limited to the above configuration. The radii of the first intermediate gear 322 and the second fixed gear 331 may be larger than the radius of the first fixed gear 311. Furthermore, the radius of the second fixed gear 331 may be larger than the radius of the first fixed gear 311 and the first intermediate gear 322. With this configuration, it is possible to function as a reduction mechanism.

[0063] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0064] 1 Seat device 10 Moving mechanism 20 Driving force transmission mechanism 30 Link mechanism 31 Guide member 32 First link 33 Second Link 34 Slide member 40 Pressing member 100 Pressing device 311 1st fixed gear 322 1st intermediate gear 331 Second fixed gear

Claims

1. A first member; a first gear that cannot rotate relatively to the first member; a first link that supports an intermediate gear that meshes with the first gear so as to be relatively rotatable and that rotates relative to the first member when a driving force is transmitted thereto; a second gear that rotates in a direction opposite to the rotation direction of the first link by meshing with the intermediate gear, the second gear being fixed, and a second link that rotates relative to the first link in the direction opposite to the rotation direction of the first link as the second gear rotates.

2. 2. The link mechanism according to claim 1, wherein the second link passes through a position where an angle between the first link and the second link is 0°, and rotates between a range where the angle between the first link and the second link is positive and a range where the angle between the first link and the second link is negative.

3. The link mechanism according to claim 1 , wherein the first gear is integrally formed with the first member.

4. The link mechanism according to claim 1 , wherein the second gear is formed integrally with the second link.

5. a third gear to which a driving force from a driving unit is transmitted is integrally formed with the first link; The link mechanism according to claim 1 , wherein the first link rotates relative to the first member in association with rotation of the third gear.

6. 2. The linkage according to claim 1, wherein a radius of the second gear is greater than a radius of the first gear.

7. a second member attached to the second link and sliding relative to the first member as the second link rotates relative to the first link; 2. The link mechanism according to claim 1, wherein a length in the longitudinal direction of the first link from a first pivot axis that is a pivot center of the first link relative to the first member to a second pivot axis that is a pivot center of the first link relative to the second member is equal to a length in the longitudinal direction of the second link from the second pivot axis to a third pivot axis that is a pivot center of the second link relative to the second member.

8. A link mechanism according to claim 7; A pressing member attached to the second member; a driving force transmission mechanism that transmits a driving force from a driving unit to the link mechanism.

9. Seat back and The pressing device according to claim 8, which is disposed on the seat back, The pressing member moves in the front-rear direction of the seat back and presses a cushion material attached to the seat back forward.

Images