Dynamic Damper

Abstract

Provided is a dynamic damper that allows a weight to be attached to a damper case without using an adhesive member.　This dynamic damper 40 comprises a weight 60, an elastic member 61 that supports the weight 60 so as to allow the weight 60 to vibrate, and a damper case 41 that houses the weight 60 and the elastic member 61. The elastic member 61 has a support part 62 that supports the weight 60 and a joining part 63 that joins to the damper case, and the damper case 41 has a fitting part 49 into which the joining part 63 of the elastic member 61 is fitted. The weight 60 is attached by fitting the joining part 63 of the elastic member 61 into the fitting part 49 of the damper case 41, and the weight 60 can therefore be assembled in the damper case 41 without using an adhesive member.

Description

[Technical Field]

[0001] The present invention relates to a dynamic damper, and more particularly to a dynamic damper equipped with a weight. [Background technology]

[0002] Some vehicle seat headrests are equipped with dynamic dampers inside, which can dampen vibrations transmitted from the vehicle body to the vehicle seat by transmitting the vibrations to the dynamic damper installed inside the headrest and causing it to resonate. Patent document 1 discloses a vehicle seat in which a dynamic damper is provided in the headrest, the dynamic damper comprising a weight, an elastic member that supports the weight so that it can vibrate, and a damper case that houses the weight and the elastic member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-111294 Summary of the Invention [Problem to be solved by the invention]

[0004] In the dynamic damper disclosed in Patent Document 1, in order to attach the weight inside the damper case, it was necessary to adhere the elastic member supporting the weight to the damper case using an adhesive such as double-sided tape. Furthermore, using an adhesive such as double-sided tape to attach the weight increases the number of parts and makes it difficult to remove the weight from the damper case once it has been attached.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a dynamic damper in which a weight can be attached to a damper case without using an adhesive member such as double-sided tape. [Means for solving the problem]

[0006] The above problem is solved by a dynamic damper of the present invention, which includes a weight, an elastic member that supports the weight so that it can vibrate, and a damper case that houses the weight and the elastic member, wherein the elastic member has a support portion that supports the weight and a joint portion that is joined to the damper case, and the damper case has a fitting portion into which the joint portion of the elastic member is fitted. The support portion of the elastic member has a base portion that abuts against an end of the weight, and a side wall portion that is connected to the end of the base and holds the side of the weight, and a through hole is formed in the peripheral portion where the base portion and the side wall portion are connected. This is solved by: The elastic member has a support portion that supports the weight and a joint portion that is joined to the damper case, and the damper case has a fitting portion into which the joint portion of the elastic member fits, so that it is possible to assemble the weight to the damper case without using an adhesive material such as double-sided tape. Furthermore, the formation of the through-holes in the peripheral edge of the elastic member is intended to position the weight, which is the member to be processed, when bonding the weight and the elastic member together in the processing step. By forming the through-holes in the peripheral edge, the position of the weight can be confirmed through the through-holes.

[0007] In the above configuration, the damper case may have a plurality of fitting portions provided so as to sandwich the weight in the vertical direction of the damper case. Since the fitting portion is arranged to sandwich the weight in the vertical direction, the dynamic damper supports the weight from the vertical direction via the elastic member, thereby improving the absorption of impacts from the left-right or front-to-back directions.

[0008] In the above configuration, the length of the fitting portion in the left-right direction may be longer than the length of the elastic member in the left-right direction. By making the left-right length of the fitting portion longer than the left-right length of the elastic member, the damper case can stably support the elastic member.

[0009] Furthermore, in the above configuration, the damper case may be composed of a first case half having an insertion opening for inserting the weight and the elastic member, and a second case half that closes the insertion opening of the first case half, and the fitting portion may be formed in a U-shape in top view in the first case half, and an opening into which the joint portion of the elastic member is inserted may be provided on the insertion opening side of the first case half. By providing an opening for inserting the joint on the insertion port side, it becomes possible to assemble the weight in one direction from the insertion port.

[0010] In the above configuration, the fitting portion may be provided with a first rib that extends in the front-rear direction of the damper case and abuts against the joint portion of the elastic member inserted into the fitting portion. By providing a first rib in the fitting portion that abuts against the joint portion, the fitting portion can be fixed more firmly.

[0011] In the above configuration, the first rib may have an end on the opening side formed with an inclined surface that decreases in height toward the opening. By forming an inclined surface on the first rib, even if there is some error in the size of the joint portion of the elastic member, particularly in the thickness, the joint portion can be fitted into the fitting portion without rattle.

[0012] Furthermore, in the above configuration, the second case half is provided with a second rib extending in the fore-and-aft direction of the damper case, and when the first case half and the second case half are combined, the second rib abuts against the opening side end of the joint portion of the elastic member inserted into the fitting portion. The second rib abuts against the end of the elastic member on the opening side, thereby restricting the elastic member from moving back and forth.

[0013] In the above configuration, it is preferable that either one of the first ribs or the second ribs is formed in a plurality of numbers, and the other rib is provided between the one of the plurality of ribs. Since one rib is provided between the other ribs, the multiple ribs can restrict the up and down movement of the elastic member. Also, because the multiple ribs abut the joint, it is possible to make it difficult for the second case half to come off the first case half.

[0015] Furthermore, in the above configuration, the fitting portions are provided above and below the damper case, the weight is supported in the up-down direction by the elastic member joined to the fitting portions, and spaces are preferably provided between the weight and the damper case in the left-right and front-rear directions. The weight is supported by fitting portions provided in the vertical direction, and spaces are provided between the weight and the damper case in the left-right and front-rear directions, making it easier to absorb impacts from the front, back, left, and right.

[0016] In the above configuration, it is preferable that the damper case has a connecting portion extending from a side wall portion thereof, and the connecting portion is connected to a frame disposed around the damper case. By connecting the damper case to the frame by the connection portion, vibrations of the damper case, which contains a built-in weight, can be reliably transmitted to the frame arranged around it. [Effects of the Invention]

[0017] According to the present invention, the elastic member has a support portion that supports the weight and a joint portion that is joined to the damper case, and the damper case has a fitting portion into which the joint portion of the elastic member fits. Therefore, it is possible to assemble the weight to the damper case without using an adhesive member such as double-sided tape. According to the present invention, since the fitting portion is arranged to sandwich the weight in the vertical direction, the dynamic damper supports the weight from the vertical direction via the elastic member, thereby improving the absorption of impacts from the left-right or front-back direction. According to the present invention, by making the left-right length of the fitting portion longer than the left-right length of the elastic member, the damper case can stably support the elastic member. According to the present invention, by providing the opening into which the joint is inserted on the insertion opening side, it is possible to assemble the weight in one direction from the insertion opening. According to the present invention, the first rib that abuts against the joint portion is provided inside the fitting portion, thereby enabling more secure fixing. According to the present invention, by forming an inclined surface on the first rib, the joint portion of the elastic member can be fitted into the fitting portion without rattle even if there is some error in the size, particularly the thickness, of the joint portion. According to the present invention, the second rib abuts against the opening side end of the elastic member, thereby restricting the elastic member from moving back and forth. According to the present invention, since one rib is provided between the other ribs, the multiple ribs can restrict the up and down movement of the elastic member. Also, since the multiple ribs abut the joint, it is possible to make it difficult for the second case half to come off the first case half. According to the present invention, the through hole is formed in the peripheral edge portion, and the position of the weight can be confirmed through the through hole. According to the present invention, the weight is supported by fitting portions provided in the vertical direction, and space is provided between the weight and the damper case in the left-right and front-to-back directions, making it easier to absorb impacts from the front, back, left, and right. According to the present invention, the damper case is connected to the frame by the connection portion, so that vibrations of the damper case containing the weight can be reliably transmitted to the frame arranged around it. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view of a vehicle seat to which a dynamic damper according to an embodiment of the present invention is attached, as viewed obliquely from the front. [Figure 2] FIG. 2 is a perspective view showing a seat frame of the vehicle seat, as viewed obliquely from the front. [Figure 3] FIG. 1 is a front view from the front of the seat showing the dynamic damper attached to the headrest frame. [Figure 4] FIG. 2 is a rear view showing the inside of the dynamic damper. [Figure 5] FIG. 2 is an exploded perspective view of the dynamic damper. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 10 is a perspective view showing a state in which the weight and the elastic member are bonded by vulcanization. [Figure 10] FIG. 10 is a perspective view showing another example of a weight. [Figure 11] FIG. 10 is a perspective view showing a weight to which another example of an elastic member is attached. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, the configuration of a dynamic damper according to this embodiment, and a headrest and a vehicle seat to which the dynamic damper is attached will be described with reference to the drawings.

[0020] In the following, a vehicle seat will be taken as an example of a vehicle seat equipped with a dynamic damper, and an example of its configuration will be described. However, the present invention is not limited to vehicle seats installed in ground-traveling vehicles with wheels such as automobiles and trains, and may also be seats installed in aircraft, ships, and other vehicles that move other than on land.

[0021] In the following description, the "front-rear direction" refers to the front-rear direction of the vehicle seat, which is the direction that coincides with the direction of travel when the vehicle is traveling. The "seat width direction" refers to the width direction of the vehicle seat, which is the direction that coincides with the left-right direction as seen by an occupant seated in the vehicle seat. The "up-down direction" refers to the up-down direction of the vehicle seat, which is the direction that roughly coincides with the vertical direction when the vehicle is traveling on a horizontal plane. The "up-down direction" of the headrest refers to the up-down direction when the seat back of the vehicle seat is upright and positioned so that an occupant can sit in it; in other words, the direction that roughly coincides with the extension direction of the seat back when the headrest is attached to the seat back.

[0022] In addition, in the following description, when various directions are described with the word "seat" added, such as "seat width direction" and "seat height direction," this indicates a direction relative to the vehicle seat, and when various directions are described with the word "vehicle" added, such as "inside of the vehicle" and "outside of the vehicle," this indicates a direction relative to the vehicle. Furthermore, unless otherwise specified, the shape, position, and posture of each part of the vehicle seat described below will be described assuming that the vehicle seat is in a seatable state.

[0023] <Basic structure of a vehicle seat> The basic configuration of a vehicle seat (hereinafter referred to as vehicle seat S) to which the dynamic damper 40 of this embodiment is attached will be described with reference to Fig. 1. Fig. 1 is a perspective view of the vehicle seat S as seen obliquely from the front. In Fig. 1, for convenience of illustration, a trim cover T (also called a skin) is removed from a portion of the vehicle seat S.

[0024] The vehicle seat S is a seat placed on the vehicle body floor and in which a vehicle occupant sits. In this embodiment, the vehicle seat S is used as a front seat corresponding to the front seat of the vehicle. However, the vehicle seat S is not limited to this, and may be a rear seat of the vehicle, or may be used as a middle seat in the second row or a rear seat in the third row in a vehicle having three rows of seats in the front-to-rear direction.

[0025] As shown in Figure 1, the vehicle seat S mainly comprises a seat back 1, which serves as the backrest portion supporting the back of the seated occupant, a seat cushion 2, which serves as the seating portion supporting the buttocks of the seated occupant, and a headrest 3, which is disposed at the upper end of the seat back 1 and supports the head of the seated occupant.

[0026] The seat back 1 is constructed by disposing a cushion pad P on a seat back frame 10 and further covering the cushion pad P with a trim cover T. The rear end of the seat cushion 2 is connected to the lower end of the seat back 1. The seat cushion 2 is also constructed by placing the cushion pad P on a seat cushion frame 20 and further covering it with the trim cover T.

[0027] The seat back 1 and the seat cushion 2 are connected with a reclining mechanism 7 (see FIG. 2) in between. The reclining mechanism 7 makes it possible to adjust the tilt angle of the seat back 1. A reclining cover 28 is provided on the side of the seat cushion 2 to protect the reclining mechanism 7 and other components. In the following description, the seat back 1 and the seat cushion 2 may be collectively referred to as a seat body Sh.

[0028] <Seat frame F> A seat frame F (frame) is provided inside the vehicle seat S, and the seat frame F is mainly composed of a seat back frame 10 that forms the skeleton of the seat back 1, a seat cushion frame 20 that forms the skeleton of the seat cushion 2, and a headrest frame 30 that forms the skeleton of the headrest 3.

[0029] <Seatback frame 10> As shown in Fig. 2, the seatback frame 10 is formed in the shape of a rectangular frame as a whole and includes an upper frame 11, a lower frame 12, and a pair of backside frames 13, 13. Each member constituting the seatback frame 10 is formed by pressing a steel plate. The pair of back side frames 13, 13 are spaced apart in the seat width direction (left-right direction). The upper frame 11 is disposed between the pair of back side frames 13, 13 and connects the upper ends of the back side frames 13, 13. The lower frame 12 is disposed between the pair of back side frames 13, 13 and connects the lower ends of the pair of back side frames 13, 13.

[0030] <Seat cushion frame 20> The seat cushion frame 20 is formed in a rectangular frame shape, and a pair of cushion side frames 21, 21 are provided on the sides thereof. The seat cushion frame 20 also has a front connecting frame 22 that connects the pair of cushion side frames 21, 21 at the front, and a rear connecting frame 23 that connects them at the rear. The front connecting frame 22 and the rear connecting frame 23 at the front and rear of the vehicle seat S are made of round pipes. A cushion pan frame 24 is provided in front of the front connecting frame 22. An S spring (not shown) or the like is attached to bridge between the cushion pan frame 24 and the rear connecting frame 23, and the S spring acts as a pressure-receiving member to support the buttocks of a seated occupant from below.

[0031] <Headrest 3 and headrest frame 30> The headrest 3 is attached to the upper end of the seat back 1 so as to support the head of a seated occupant. A headrest frame 30 that forms the framework of the headrest 3 is provided inside the headrest 3 as shown in Fig. 2. The headrest frame 30 has a pair of pillar portions 31, 31 (called headrest pillars or headrest stays) disposed on the left and right, and an upper portion 32 that is connected to the upper ends of each of the pair of pillar portions 31, 31.

[0032] The headrest 3 is attached to the seatback frame 10 by inserting the lower ends of the pillar portions 31, 31 into headrest guides 14 attached to the upper frame 11 of the seatback frame 10. In addition, a dynamic damper 40 is attached to the headrest frame 30.

[0033] The headrest frame 30 is formed by bending a metal pipe material multiple times. Each of the pair of pillar portions 31 has a first extending portion 31a extending downward from a connecting portion with the upper portion 32, a second extending portion 31b bending at the lower end of the first extending portion 31a and extending rearward, and a third extending portion 31c bending at the rear end of the second extending portion 31b and extending downward. More precisely, the second extending portions 31b extend in a V-shape with their rear ends widening outward when viewed from above. The dynamic damper 40 is attached by utilizing the upper portion 32 and the first extension portions 31a, 31a of the pair of pillar portions 31, 31.

[0034] 3, the second extending portions 31b, 31b are formed so as to be positioned above the lower end of the damper case 41 of the dynamic damper 40. In other words, the damper case 41 can be attached so that its lower end is lower than the second extending portions 31b, 31b. By positioning the second extension portions 31b, 31b of the headrest frame 30 above the lower end of the damper case 41, the headrest frame 30 becomes more compact, and the headrest 3 can be made smaller.

[0035] <Cushion pad P and trim cover T> A cushion pad P and a trim cover T are provided on the outer sides of the seat back frame 10, the seat cushion frame 20 and the headrest frame 30, thereby forming the seat back 1, the seat cushion 2 and the headrest 3. The cushion pad P has a cushion portion formed from a foam material, which is covered by a trim cover T. The cushion pad P is a urethane base material formed by foam molding using, for example, a urethane foam material. Examples of the foam material include polypropylene bead foam, polyethylene bead foam, polypropylene foam, polyethylene foam, acrylonitrile-styrene foam, ethylene vinyl acetate copolymer resin, urethane foam material, etc., or a combination of these. The trim cover T is made of, for example, fabric, film, cloth, leather, or sheet, and is attached so as to cover the cushion pad P in a stretched state with a predetermined tension.

[0036] <Slide mechanism 4> 2, a slide mechanism 4 is installed under the vehicle seat S. The slide mechanism 4 allows the seat body Sh of the vehicle seat S to be attached to the vehicle floor in a state where it can slide in the front-rear direction.

[0037] The slide mechanism 4 is a device for sliding the vehicle seat S in the front-rear direction and has a known structure (a general structure of a slide mechanism). The slide mechanism 4 has lower rails 26 fixed on the vehicle floor and upper rails 27 that support the seat body Sh and are slidable relative to the lower rails 26.

[0038] <Dynamic Damper 40> The dynamic damper 40 provided in the vehicle seat S of this embodiment will be described below with reference to FIGS. FIG. 3 is a front view showing the dynamic damper 40 attached to the headrest frame 30. FIG. 4 is a rear view showing the interior of the dynamic damper 40. FIG. 5 is an exploded perspective view of the dynamic damper 40. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4, FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 4, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 4. FIG. 9 is a perspective view showing a state in which the weight 60 and the elastic member 61 are vulcanization-bonded together. FIG. 10 is a perspective view showing a weight 60A, which is another example of the weight 60. FIG. 11 is a perspective view showing a weight 60B to which an elastic member 61B, which is another example of the elastic member 61, is attached.

[0039] By providing a dynamic damper 40 inside the headrest 3 of the vehicle seat S, the vibration transmitted from the vehicle body to the vehicle seat S can be transmitted to the dynamic damper 40 and resonated, thereby suppressing the vibration of the vehicle seat S.

[0040] As shown in FIGS. 4 and 5, the dynamic damper 40 includes a weight 60, an elastic member 61 that supports the weight 60 so that it can vibrate, and a damper case 41 that houses the weight 60 and the elastic member 61.

[0041] <60 weights> The weight 60 is a member that is supported in a vibratory manner within the damper case 41 using an elastic member 61. The weight 60 is made of metal (for example, cast iron), and in this embodiment, the weight 60 has a vertically elongated rectangular prism shape with rounded corners as shown in Fig. 4. Elastic members 61, 61 that support the weight 60 in a vibratory manner are attached to the upper and lower ends of the weight 60, respectively.

[0042] <Elastic member 61> Each of the elastic members 61 has a support portion 62 that supports the weight 60, and a joint portion 63 that extends from the support portion 62 and is joined to the damper case 41. The joint portion 63 is fitted into a fitting portion 49 of the damper case 41, which will be described later. The elastic member 61 in this embodiment is made of rubber, but may also be made of resin.

[0043] The support portion 62 is formed to cover the upper or lower end of the weight 60, and has a base portion 62a that abuts against the upper or lower end of the weight 60, and a side wall portion 62b that connects to the peripheral end of the base portion 62a and holds the side of the weight 60. A confirmation hole 62c (through hole) is formed in the corner where the base 62a and the side wall 62b connect, in other words, in the peripheral portion where the base 62a and the side wall 62b connect. The elastic member 61 and the end of the weight 60 are fixed with an adhesive or the like. The formation of the confirmation hole 62c in the peripheral portion of the elastic member 61 is intended to position the weight 60, which is the member to be processed, when bonding the weight 60 and the elastic member 61 together in the processing step. By providing the confirmation hole 62c, it is possible to check whether the end of the weight 60 is properly inserted into the support portion 62 during bonding.

[0044] The joint 63 of the elastic member 61 is formed in a T-shape in side view, and is composed of a plate-like portion 63a and a shaft portion 63b that connects the plate-like portion 63a and the support portion 62. The shaft portion 63b extends from the center of the plate-like portion 63a in the up-and-down direction, in other words, in the longitudinal direction of the weight 60, and is connected to the base 62a of the support portion 62. The shaft portion 63b can flex back and forth and left and right, thereby supporting the weight 60 so that it can vibrate. Furthermore, the plate-shaped portion 63a is a flat portion formed with a predetermined thickness, and the weight 60 is fixed inside the damper case 41 by inserting the plate-shaped portion 63a into the fitting portion 49 of the damper case 41 described later.

[0045] <Damper Case 41> The damper case 41 will now be described. The damper case 41 is divided into two parts in the front-to-rear direction, and is composed of a first case half 42 that is disposed on the front side when installed on the headrest 3, and a second case half 43 that is disposed on the rear side. The first case half 42 and the second case half 43 are each formed from a synthetic resin.

[0046] 5, the first case half 42 has an insertion opening for inserting the weight 60 and the elastic member 61. The second case half is formed so as to close the insertion opening. The length L1 of the first case half 42 in the front-to-rear direction is formed to be longer than the length L2 of the second case half 43 in the front-to-rear direction (see FIG. 6). By increasing the length L1 of the first case half 42, the weight 60 and the elastic member 61 can be stored inside the first case half 42.

[0047] <Fitting part 49> The first case half 42 of the damper case 41 is provided with a fitting portion 49 into which the joint portion 63 of the elastic member 61 fits. 5 and 6, the fitting portion 49 is formed in a U-shape in top view on the first case half 42. The fitting portion 49 is formed with an opening 49d into which the plate-like portion 63a of the joint portion 63 is inserted, and a slit 49c through which the shaft portion 63b passes. The opening 49d is provided on the insertion opening side of the first case half 42. Since the dynamic damper 40 has the fitting portion 49 in the damper case 41 that fits with the elastic member 61, the weight 60 can be attached to the damper case 41 without using an adhesive such as double-sided tape. Furthermore, by providing the opening 49d on the insertion opening side of the first case half 42, when attaching the weight 60, the weight 60 can be assembled in one direction from the insertion opening.

[0048] Two fitting portions 49 are provided corresponding to the elastic member 61 that supports the weight 60. The two fitting portions 49 are provided inside the damper case 41 so as to sandwich the weight 60 in the vertical direction. Since the fitting portions 49 are arranged to sandwich the weight 60 in the vertical direction, the dynamic damper 40 supports the weight 60 from the vertical direction via the elastic member 61. This improves the ability to absorb impacts from the left-right or front-rear direction. If elastic members 61 are further provided on the left and right sides of the weight 60, fitting portions 49 may be provided in the left and right directions inside the damper case 41 corresponding to the elastic members 61.

[0049] Furthermore, the fitting portion 49 is formed so that its left-right length W1 (see FIG. 4) is longer than the left-right length W2 of the elastic member 61. By forming the left-right length W1 of the fitting portion 49 longer than the left-right length W2 of the elastic member 61, the damper case 41 can stably support the elastic member 61.

[0050] <First rib 49a> 4 to 6, two first ribs 49a extending in the front-rear direction of the damper case 41 are provided inside the fitting portion 49. The first ribs 49a are formed so as to come into contact with the plate-shaped portion 63a of the joint portion 63 inserted into the fitting portion 49. As shown in FIG. 8, the first rib 49a has an end 49e on the opening 49d side that forms an inclined surface whose height decreases toward the opening 49d. The first rib 49a prevents the elastic member 61 from moving in the vertical direction, and allows the elastic member 61 to be firmly fixed. Furthermore, since an inclined surface is formed on the first rib 49a, even if there is some error in the size, particularly the thickness, of the plate-shaped portion 63a of the joint 63, it can be inserted into the fitting portion 49, and the joint 63 can be fitted into the fitting portion 49 without any rattling.

[0051] <Second rib 49b> 6 and 7, the second case half 43 is provided with a second rib 49b extending in the front-rear direction of the damper case 41, that is, extending from the back surface of the second case half 43 toward the front. When the first case half 42 and the second case half 43 are combined, the second rib 49b is inserted into the mating portion 49 through the opening 49d and is configured to abut against the plate-shaped portion 63a of the joint 63 (more specifically, the opening side end 63c and the upper or lower surface of the plate-shaped portion 63a). The second rib 49b comes into contact with the opening side end 63c of the plate-shaped portion 63a, thereby restricting the elastic member 61 from moving back and forth.

[0052] The damper case 41 of this embodiment is provided with two first ribs 49a, and the second rib 49b is provided between the two first ribs 49a. The multiple ribs abut against the plate-shaped portion 63a, and the plate-shaped portion 63a is supported and sandwiched by the bottom surface of the fitting portion 49, thereby restricting the vertical movement of the joint portion 63. Furthermore, the first rib 49a and the second rib 49b abut against the plate-shaped portion 63a, making it difficult for the second case half 43 to come off the first case half 42.

[0053] 4, the weight 60 is supported in the vertical direction within the damper case 41 by an elastic member 61 that fits into the fitting portion 49. Therefore, a space is provided between the weight 60 and the damper case 41 in the left-right and front-rear directions. This makes it easy to absorb impacts from the front-rear and left-right directions. It is preferable that this space (gap) be formed so that the distance between the weight 60 and the damper case 41 is approximately 6.0 mm.

[0054] <Fitting groove 44 and fitting protruding wall 45> A rectangular fitting groove 44 and a fitting protrusion wall 45 that can fit together are formed on one and the other of the opposing surfaces of the second case half 43. A plurality of fixing claws 46, 46... that protrude outward are formed at the tip of the fitting protrusion wall 45. In addition, a plurality of fixing holes 47, 47... that can elastically snap into engagement with these fixing claws 46, 46... are formed at the bottom of the fitting groove 44.

[0055] After attaching the elastic member 61 to the weight 60, the joint portion 63 of the elastic member 61 is joined to the fitting portion 49 provided on the first case half 42, thereby fixing the weight 60 to the first case half 42. The fitting protruding wall 45 of the second case half 43 is fitted into the fitting groove 44 of the first case half 42. The engagement between the fixing claws 46, 46... and the fixing holes 47, 47... makes it possible to easily join the first case half 42 and the second case half 43 without using screws, and at the same time, the weight 60 can be supported by the damper case 41 via the elastic member 61.

[0056] <Connection part 50> The connecting portion 50 provided on the dynamic damper 40 will be described. The dynamic damper 40 has the connecting portion 50 provided on the first case half 42 for connecting to the headrest frame 30 arranged around the damper case 41. The connecting portion 50 extends from the side wall portion of the damper case 41. More specifically, as shown in FIG. 3, the connecting portion 50 for connecting to the headrest frame 30 is provided on each of the left and right side wall portions (left side wall portion 41a, right side wall portion 41b) and the upper side wall portion (upper side wall portion 41c) of the damper case 41.

[0057] Of the connecting portions 50, the connecting portions 50 (first connecting portion 51 and second connecting portion 52) provided on the left and right side wall portions of the damper case 41 are arranged at positions that do not overlap with the vertical center portion of the damper case 41. More specifically, the first connecting portion 51 provided on the left side wall portion (left side wall portion 41a) and the second connecting portion 52 provided on the right side wall portion (right side wall portion 41b) are arranged above the vertical center portion of the damper case 41. Furthermore, as the connection portion 50, a third connection portion 53 that connects to the upper portion 32 of the headrest frame 30 is provided on the upper side wall portion (upper side wall portion 41c). No connection portion 50 is provided on the lower side wall portion of the damper case 41.

[0058] The first connecting portion 51, the second connecting portion 52, and the third connecting portion 53 that constitute the connecting portion 50 are formed integrally with the first case half . The upper portion of the damper case 41 is supported by the headrest frame 30 by the connecting portion 50, so that the damper case 41 can be extended downward. Since the damper case 41 does not need to be extended upward and the headrest 3 does not protrude upward, the headrest 3 can be made into a more compact shape.

[0059] Furthermore, providing the connection portion 50 makes it easier to attach the damper case 41 to the headrest frame 30. Furthermore, with the first case half 42 attached to the headrest frame 30, the second case half 43 can be removed, and the weight 60 can be attached or removed together with the stored weight 60 and elastic member 61. The connection portion 50 will be described in more detail below.

[0060] <First connection portion 51> The first connecting portion 51 is made of a plate-like member that is formed in an S-shape when viewed from above and protrudes outward from the left side wall portion 41a. The first connecting portion 51 is made up of a linking portion 51a and a gripping portion 51b. The connecting portion 51a is formed in an L-shape when viewed from above, with its base connected to the first case half and connecting the grip portion 51b and the left side wall portion 41a of the first case half . The grip portion 51b is formed in a major arc shape at the tip of the first connection portion 51 to snap-engage with the first extension portion 31a of the headrest frame 30 so as to grip the first extension portion 31a of the headrest frame 30. As shown in Fig. 5, the grip portion 51b is connected to the front surface of the headrest frame 30.

[0061] <Second connecting portion 52> The second connecting portion 52 is made up of a plate-like member that is formed in an S-shape in top view and protrudes outward from the right side wall portion 41b. The second connecting portion 52 is made up of a linking portion 52a and a gripping portion 52b. The connecting portion 52a is formed in an L-shape when viewed from above, with its base connected to the first case half and connecting the grip portion 52b and the right side wall portion 41b of the first case half . The grip portion 52b is formed in a major arc shape at the tip of the second connecting portion 52 to snap-engage with the first extending portion 31a of the headrest frame 30. As shown in Fig. 5, the grip portion 52b is connected to the front surface of the headrest frame 30.

[0062] <Third connection portion 53> The third connecting portion 53 is formed in an inverted U-shape in a side view so as to protrude outward from the upper sidewall portion 41c. The third connecting portion 53 is composed of a linking portion 53a and a gripping portion 53b. The connecting portion 53a connects the grip portion 53b and the upper side wall portion 41c of the first case half 42. The grip portion 53b is formed in a major arc shape at the tip of the third connecting portion 53 for snap engagement so as to grip the upper portion 32 of the headrest frame 30. As shown in FIG. 5, the grip portion 53b is connected to the upper surface of the headrest frame 30. The third connection portion 53 is located between the first connection portion 51 and the second connection portion 52 in the left-right direction. The third connecting portion 53 can restrict vertical movement of the damper case 41. By supporting the damper case 41 with the first connecting portion 51, the second connecting portion 52, and the third connecting portion 53, the damper case 41 can be stably fixed to the headrest frame 30.

[0063] <Reinforcement part 56> Reinforcement portions 56 are provided at the linking portions 51a, 52a of the first connecting portion 51 and the second connecting portion 52. As shown in Fig. 3, the reinforcement portions 56 are composed of an upper reinforcement portion 56a disposed on the upper side and a lower reinforcement portion 56b disposed on the lower side of the linking portions 51a, 52a. In this embodiment, reinforcement is provided by two reinforcement portions 56 disposed one above the other, but the number of reinforcement portions 56 may be one, or three or more. By providing the reinforcing portion 56, the damper case 41 can be fixed to the headrest frame 30 more stably.

[0064] <Through hole 58, notch 57> The gripping portion 51b of the first connecting portion 51 and the gripping portion 52b of the second connecting portion 52 each have a through hole 58 formed therein. The through hole 58 is located between adjacent ones of the multiple reinforcing portions 56 provided in the vertical direction. Specifically, the through hole 58 is located between the upper reinforcing portion 56a and the lower reinforcing portion 56b in the vertical direction. Furthermore, each of the upper reinforcing portion 56a and the lower reinforcing portion 56b has a notch 57. Furthermore, by forming the notch 57 and the through-hole 58 in the first connecting portion 51 and the second connecting portion 52, weight reduction can be achieved. Furthermore, by forming the through holes 58 and the notches 57 in the first connecting portion 51 and the second connecting portion 52, the dynamic damper 40 can move more elastically, making it easier to attach the dynamic damper 40 to the headrest frame 30.

[0065] <Assembly procedure> The assembly procedure for the dynamic damper 40 described above is as follows. 1. The weight 60 to which the elastic member 61 is attached is assembled to the first case half 42. A space is formed between the first case half 42 and the weight 60. 2. The first case half 42 to which the weight 60 is attached is covered with the second case half 43. 3. The first case half 42 and the second case half 43 are attached to the headrest frame 30 using the connecting parts 50.

[0066] <How to attach the weight> As described above, the weight 60 is made of metal, and the elastic member 61 that supports the weight 60 so that it can vibrate is made of rubber. The weight 60 is preferably attached to the elastic member 61 by vulcanization adhesion. For example, as shown in Fig. 9, vulcanization bonding is performed by applying adhesive to both ends of a weight 60 and then covering them with an elastic member 61. At this time, the elastic member 61 is placed on a base 70 in order to apply heat and pressure to the elastic member 61. By placing it on the base 70, heat and pressure are applied to the elastic member 61 from the base 70. After bonding by applying heat and pressure, the weight 60 and elastic member 61 are removed from the base 70 and allowed to cool. Applying heat and pressure to the bonded area causes a cross-linking reaction in the adhesive at the rubber interface, increasing adhesive strength. Vulcanization bonding produces stronger bonds than when the adhesive is cured at room temperature.

[0067] <Another example of a weight> Although the weight 60 has been formed in the shape of a rectangular prism, the shape of the weight 60 is not limited to this. For example, the weight 60 may be formed in the shape of a vertically elongated cylinder, as in the weight 60A shown in FIG. 10 is supported by an elastic member 61A so that it can vibrate. The elastic member 61A is composed of a support portion 62A that supports the weight 60A and a joint portion 63 that is joined to the damper case 41. The support portion 62A of the elastic member 61A is formed in a cylindrical shape to match the cylindrical shape of the weight 60A. The elastic member 61A and the weight 60A are preferably bonded together by vulcanization bonding. The support portion 62A is formed to cover the upper or lower end of the weight 60A, and has a base portion 62Aa that abuts against the upper or lower end of the weight 60A, and a side wall portion 62Ab that connects to the peripheral edge of the base portion 62Aa and holds the side of the weight 60A. A confirmation hole 62Ac is formed in the peripheral edge where the base portion 62Aa and the side wall portion 62Ab are connected. The structure of the joint 63 is similar to that of the joint 63 of the elastic member 61 that supports the weight 60, so the same reference numerals are used for corresponding parts and redundant explanations will be omitted. The weight 60A can be easily attached by fitting the joint 63 into the fitting portion 49 of the damper case 41. Furthermore, because the weight 60A is cylindrical, it can stably absorb vibrations not only in the front-rear and left-right directions, but also in diagonal directions.

[0068] 10 has a part of its side covered by an elastic member 61A, but it may be configured so that substantially the entire surface is covered by an elastic member 61B, as in the case of a weight 60B shown in Fig. 11. More specifically, the surface of the weight 60B other than the portion exposed by the confirmation hole 62Bc is covered by a base 62Ba and a side wall 62Bb of the elastic member 61B. By covering the entire surface of the weight 60B with the elastic member 61B, the weight 60B can be protected from damage due to external impacts and the like.

[0069] The embodiments of the present invention have been described above using the drawings. Note that the above-described embodiments are merely examples for facilitating understanding of the present invention and are not intended to limit the present invention. In other words, the present invention may be modified or improved without departing from the spirit thereof, and the present invention naturally includes equivalents thereof. [Explanation of symbols]

[0070] S Vehicle seat (vehicle seat) Sh seat body Front seat frame (frame) P cushion pad T trim cover 1 seat back 2 seat cushions 3 Headrest 4 Slide mechanism 7 Reclining mechanism 10 Seat back frame 11 Upper frame 12 Lower frame 13 Backside frame 20 Seat cushion frame 21 Cushion side frame 22 Front connecting frame 23 Rear connecting frame 24 Cushion Pan Frame 26 Lower rail 27 Upper Rail 28 Reclining cover 30 Headrest frame 31 Pillar section 31a 1st extension part 31b Second extension 31c 3rd extension 32 Upper part 40 Dynamic Damper 41 Damper case 41a Left side wall 41b Right side wall 41c Upper side wall 42 First case half 43 Second case half 44 Fitting groove 45 Fitting wall 46 Fixed claw 47 Fixing hole 49 Fitting part 49a 1st Rib 49b 2nd Rib 49c slit 49d opening 49e end 50 Connection 51 First connection part 51a Connection part 51b Grip part 52 Second connection part 52a Connection part 52b Grip part 53 Third connection part 53a Connection part 53b Grip part 56 Reinforcement 56a Upper reinforcement 56b Lower reinforcement 57 Notch 58 Through Hole 60, 60A, 60B weight 61, 61A, 61B Elastic member 62, 62A, 62B Support part 62a, 62Aa, 62Ba base 62b, 62Ab, 62Bb side wall 62c, 62Ac, 62Bc confirmation hole (through hole) 63 Joint 63a Plate-shaped part 63b Shaft 63c Opening side end

Claims

1. A weight and an elastic member that supports the weight so that the weight can vibrate; a damper case that houses the weight and the elastic member, the elastic member has a support portion that supports the weight and a joint portion that is joined to the damper case, the damper case has a fitting portion into which the joint portion of the elastic member fits, the support portion of the elastic member has a base portion that abuts against an end portion of the weight, and a side wall portion that is connected to the end portion of the base and holds a side portion of the weight, A dynamic damper, characterized in that a through hole is formed in a peripheral portion where the base portion and the side wall portion are connected.

2. 2. The dynamic damper according to claim 1, wherein the damper case has a plurality of fitting portions provided thereon so as to sandwich the weight in the vertical direction of the damper case.

3. 2. The dynamic damper according to claim 1, wherein the length of the fitting portion in the left-right direction is longer than the length of the elastic member in the left-right direction.

4. the damper case is composed of a first case half having an insertion opening for inserting the weight and the elastic member, and a second case half closing the insertion opening of the first case half, 2. The dynamic damper according to claim 1, characterized in that the fitting portion is formed in a U-shape in top view in the first case half, and an opening into which the joint portion of the elastic member is inserted is provided on the insertion port side of the first case half.

5. The dynamic damper according to claim 4, characterized in that the fitting portion is provided with a first rib extending in the front-to-rear direction of the damper case and abutting against the joint portion of the elastic member inserted into the fitting portion.

6. 6. The dynamic damper according to claim 5, wherein an inclined surface is formed at an end of the first rib on the opening side, the inclined surface decreasing in height toward the opening.

7. The second case half is provided with a second rib extending in the front-rear direction of the damper case, The dynamic damper according to claim 5, characterized in that, when the first case half and the second case half are combined, the second rib abuts against the opening side end of the joint portion of the elastic member inserted into the fitting portion.

8. 8. The dynamic damper according to claim 7, wherein either one of the first ribs or the second ribs is formed in a plurality of numbers, and the other rib is provided between the one of the plurality of ribs.

9. The fitting portions are provided on the top and bottom of the damper case, the weight is supported in the up-down direction by the elastic member joined to the fitting portion, 2. The dynamic damper according to claim 1, wherein a space is provided between the weight and the damper case in the left-right and front-rear directions.

10. a connecting portion extending from a side wall portion of the damper case; The dynamic damper according to claim 1 , wherein the connecting portion is connected to a frame disposed around the damper case.

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