JP7627641B2 - Headrest bush and headrest device - Google Patents

Description

The present invention relates to a headrest bush and a headrest device.

The following Patent Document 1 discloses a headrest bushing that supports a headrest on a seat back, the headrest having a stay protruding therefrom and having multiple height adjustment grooves along the axial direction. In this headrest bushing, a holder attached to the upper end of the seat back is formed with a through hole (stay insertion hole) into which the headrest stay is inserted. This holder has an operating part restraint hole (lock accommodating hole) into which a lock is inserted, and the lock is biased in the direction of engagement with the stay. The lock fits into the height adjustment groove of the stay, thereby restricting displacement of the stay relative to the headrest bushing.

JP 2004-345463 A

In recent years, electrical devices such as speakers are sometimes installed in headrests. Such headrests have a large mass, and when the headrest is displaced relative to the seat back due to vibrations while the vehicle is moving, the lock against the holder may rattle, causing abnormal noise. If the precision of the holder and lock is increased to prevent this abnormal noise, manufacturing becomes complicated.

In consideration of the above, the present invention aims to provide a headrest bush that can prevent the generation of abnormal noise and is easy to manufacture, and a headrest device equipped with the headrest bush.

The headrest bush of the first aspect includes a holder in which a stay insertion hole is formed for inserting a headrest stay in the axial direction, and a lock accommodating hole is formed that opens to one side in a stay-orthogonal direction perpendicular to the axial direction and intersects with the stay insertion hole, and a lock that is inserted into the lock accommodating hole and is biased in the stay-orthogonal direction to engage with the stay, the lock accommodating hole is formed in a tapered shape that expands in the axial direction toward the opening side of the lock accommodating hole, the lock has a front-side convex portion that protrudes to one side in the axial direction on the front side of the lock accommodating hole, and the axial dimension is set larger on the front side of the lock accommodating hole than on the back side of the lock accommodating hole.

According to the first aspect of the headrest bush, the holder is formed with a stay insertion hole into which the headrest stay is inserted in the axial direction, and a lock accommodating hole that opens to one side in the stay orthogonal direction perpendicular to the axial direction of the stay and intersects with the stay insertion hole. The lock is inserted into the lock accommodating hole and is urged in the stay orthogonal direction to engage with the stay. The lock accommodating hole is formed in a tapered shape that expands in the axial direction toward the opening side of the lock accommodating hole. This allows the draft taper to be set when the holder is manufactured by injection molding. The lock has a front side protrusion that protrudes to one side in the axial direction on the front side of the lock accommodating hole, and the axial dimension is set to be larger on the front side of the lock accommodating hole than on the back side of the lock accommodating hole. This effectively suppresses the rattle of the lock in the tapered lock accommodating hole, thereby preventing the generation of abnormal noise. Moreover, the rattle can be suppressed by pinpointing the accuracy of the protruding height of the front side protrusion, making the manufacturing easy.

In the second aspect of the headrest bush, in the first aspect, one side in the axial direction is the upper side of the headrest.

In the second embodiment of the headrest bush, the protruding portion on the front side formed on the lock protrudes upward from the headrest. This prevents the protruding portion from contacting the holder under normal conditions, thereby preventing or suppressing deformation of the protruding portion on the front side.

The headrest bush of the third aspect is the first or second aspect, and the lock has two of the front side protrusions aligned in an alignment direction perpendicular to the axial direction and the stay perpendicular direction.

In the headrest bush of the third embodiment, the two front-side protrusions are aligned in the above-mentioned alignment direction, so the two front-side protrusions can effectively suppress rattling of the lock with respect to the holder. Moreover, it is easier to ensure the precision of each front-side protrusion, compared to, for example, a case in which the front-side protrusions are formed elongated in the alignment direction.

The fourth aspect of the headrest bush is any one of the first to third aspects, in which the lock has a rear-side protrusion that protrudes to one side in the axial direction at the rear side of the lock receiving hole, and the protruding height of the front-side protrusion is set to be greater than the protruding height of the rear-side protrusion.

In the fourth embodiment of the headrest bush, the lock has a front-side convex portion that protrudes to one side in the axial direction on the front side of the lock accommodating hole, and a rear-side convex portion that protrudes to one side in the axial direction on the rear side of the lock accommodating hole. The protruding height of the front-side convex portion is set to be greater than the protruding height of the rear-side convex portion. This sets the axial dimension of the lock to be greater on the front side of the lock accommodating hole than on the rear side of the lock accommodating hole. By pinpointing the accuracy of the protruding heights of these front-side convex portion and rear-side convex portion, the aforementioned rattle can be suppressed, making manufacturing easy.

The headrest bush of the fifth aspect is the fourth aspect, in which the lock has two rear-side convex portions aligned in a direction perpendicular to the axial direction and the stay-orthogonal direction, and two front-side convex portions aligned in the direction.

In the headrest bush of the fifth aspect, the two rear convex portions and the two front convex portions are aligned in the above-mentioned alignment direction, so the four convex portions effectively suppress rattling of the lock with respect to the holder. Moreover, it is easier to ensure the precision of each convex portion compared to, for example, forming the rear convex portions and the front convex portions elongated in the alignment direction.

The headrest device of the sixth aspect comprises a pair of left and right headrest bushes arranged side by side in the left-right direction of the seat at the upper end of the seat back, and a headrest in which a pair of left and right stays extending from a main body on which electrical equipment is mounted are supported by the seat back via the left and right headrest bushes, one of the left and right headrest bushes being a headrest bush of any one of the first to fifth aspects, one of the left and right stays being inserted into the stay insertion hole of the holder of the one of the headrest bushes, and only one notch is formed in the one of the stays into which the lock of the one of the headrest bushes can be fitted.

According to the sixth aspect of the headrest device, a pair of left and right headrest bushes are provided at the upper end of the seat back, aligned in the left-right direction of the seat. The headrest has a pair of left and right stays extending from a main body on which electrical equipment is mounted, and is supported on the seat back via the left and right headrest bushes. One of the left and right headrest bushes is a headrest bush of any one of the first to fifth aspects. One of the left and right stays is inserted into a stay insertion hole of a holder provided in one of the headrest bushes, and only one notch is formed in the one stay into which a lock provided in one of the headrest bushes can be fitted. In this headrest device, for example, the other headrest bush can be used for adjusting the height of the headrest, and the one headrest bush can be used for preventing the headrest from being removed from the seat back. This makes it possible to prevent the headrest, which has a large mass due to the electrical equipment mounted in the main body, from accidentally coming off the seat back due to an impact or the like. Moreover, since one headrest bush is one of the first to third aspects, the same effect as any one of the aspects can be obtained.

As described above, the headrest bushing of the present invention can prevent the generation of abnormal noise and is easy to manufacture.

1 is a perspective view showing a vehicle seat including a headrest device according to an embodiment; FIG. 2 is a perspective view showing a headrest provided in the headrest device. FIG. 2 is a perspective view showing a headrest bush according to the embodiment. FIG. 2 is an exploded perspective view showing the headrest bush. 5 is a cross-sectional view showing a cut surface along the line F5-F5 in FIG. 3. 6 is a cross-sectional view showing a cut surface taken along line F6-F6 in FIG. 3. 13 is a perspective view showing a lock provided in a headrest bush. FIG. 11 is a schematic diagram for explaining the dimensional relationship of a gap between a lock and a lock receiving hole formed in a holder; FIG. 11 is a schematic diagram for explaining the control dimensions of a lock receiving hole. FIG. FIG. 13 is a schematic diagram for explaining the management dimensions of the lock. 11 is a perspective view showing a state in which the headrest is restrained in the uppermost position relative to the seat back and none of the left and right headrest bushes are locked. FIG. FIG. 13 is a perspective view showing a state in which a right headrest bush according to the embodiment is locked. 11 is a perspective view showing a state in which the headrest is positioned at the top position of the height adjustment range and the left headrest bush for height adjustment is locked. FIG. 11 is a perspective view showing a state in which the headrest is located at the lowest position of the height adjustment range and the left headrest bush for height adjustment is locked. FIG. FIG. 11 is a schematic diagram showing a first modified example of the lock and corresponds to FIG. 10 . FIG. 8 is a perspective view corresponding to FIG. 7 and showing a second modified example of the lock.

Headrest device 16 and headrest bushing 30R according to an embodiment of the present invention will be described below with reference to Figures 1 to 15. Note that in each figure, some reference numerals may be omitted in order to make the drawings easier to understand.

1 shows a perspective view of a vehicle seat 10 including a headrest device 16 according to this embodiment. The vehicle seat 10 includes a seat cushion 12, a seat back 14, and a headrest device 16. The headrest device 16 includes a headrest 18 and a pair of left and right headrest bushes 30L and 30R. FIG. 1 shows the left and right headrest bushes 30L and 30R in a schematic manner. The arrow FR in each drawing indicates the front direction of the vehicle seat 10, the arrow UP indicates the upward direction of the vehicle seat 10, and the arrow LH indicates the left direction of the vehicle seat 10. The front-rear direction of the vehicle seat 10 corresponds to the "arrangement direction" in the present invention, the up-down direction of the vehicle seat 10 corresponds to the "axial direction" in the present invention, and the left-right direction of the vehicle seat 10 corresponds to the "stay perpendicular direction" in the present invention. Hereinafter, when the front-rear, left-right, up-down directions are simply used, they are used to indicate the directions relative to the vehicle seat 10.

The headrest 18 has a main body 20 on which a speaker 22 (not shown in any figures other than FIG. 1) is mounted, which is an electrical device, and a pair of left and right stays 24L, 24R extending downward from the main body 20. The left and right headrest bushes 30L, 30R are arranged side by side in the left-right direction at the upper end of the seat back 14. The left and right stays 24, 26 of the headrest 18 are inserted into stay insertion holes 38L, 38R formed in the left and right headrest bushes 30L, 30R, and are supported (connected) to the seat back 14 via the left and right headrest bushes 30L, 30R. As shown in FIG. 2, a plurality of notches 26 (four in this example) are formed side by side in the vertical direction on the right side surface of the left stay 24L, and one notch 28 is formed on the right side surface of the right stay 24R. The notch 28 formed in the right stay 24R is located slightly below the lowest notch 26 of the multiple notches 26 formed in the left stay 24L.

The left headrest bush 30L is for height adjustment, adjusting the height position of the headrest 18 relative to the seat back 14. The right headrest bush 30R corresponds to the "headrest bush" in this invention, and is for preventing the headrest 18 from accidentally coming off the seat back 14 due to an impact during a vehicle collision. The left headrest bush 30L for height adjustment is a general one, so a detailed description will be omitted here. Note that the left-right arrangement of each component in this embodiment is merely an example, and the configuration may be formed symmetrically to this embodiment.

As shown in Figures 3 to 6, the right headrest bush 30R (hereinafter simply referred to as "headrest bush 30R") is composed of a holder 32, a lock 42, a spring 54, and a cover 56. The holder 32 is manufactured, for example, by injection molding of resin, and has a cylindrically formed tube portion 34 and a lock accommodating portion 36 formed at one end of the axial direction of the tube portion 34. The holder 32 is formed with a stay insertion hole 38R that passes through the tube portion 34 and the lock accommodating portion 36 in the axial direction of the tube portion 34.

The tubular portion 34 is inserted from above into a tubular bracket provided at the upper end of a frame (not shown) of the seat back 14, and an elastically deformable claw portion 34A formed at the lower portion of the tubular portion 34 is hooked onto the lower end of the bracket. This causes the headrest bush 30R to be attached to the frame of the seat back 14. The headrest bush 30R is supported by the frame of the seat back 14 in a position in which the axial direction of the tubular portion 34 is aligned in the vertical direction and the lock accommodating portion 36 is located at the upper end. The lock accommodating portion 36 is formed in a brim shape at the upper end of the tubular portion 34 and is arranged to protrude upward from the upper surface of the seat back 14. The lock accommodating portion 36 is formed with a lock accommodating hole 40 that opens to one side in the left-right direction (here, the left side) and intersects with the stay insertion hole 38R. A lock 42 is inserted into the lock accommodating hole 40.

The lock 42 is composed of a lock body 44 and a stopper 50. The lock body 44 is manufactured, for example, by injection molding of resin, and is formed in a plate shape (approximately rectangular frame shape) with the left-right direction as the longitudinal direction and the up-down direction as the thickness direction. A stay insertion hole 52 is formed in the center of the lock body 44 for inserting the right stay 24R of the headrest 18. Elastically deformable removal prevention claws 44A protruding to both sides in the front-rear direction are formed on both ends of the lock body 44 in the front-rear direction. When the lock body 44 is inserted into the lock accommodating hole 40, the front and rear removal prevention claws 44A are elastically deformed inward in the front-rear direction and then elastically return to their original state. As a result, the front and rear removal prevention claws 44A are caught on the step portions 40A (see FIG. 6) formed on the front and rear walls of the lock accommodating hole 40, and the removal of the lock body 44 from the lock accommodating hole 40 is restricted.

A spring 54 is disposed between the right wall of the lock receiving hole 40 and the right end of the lock body 44. The spring 54 is a compression coil spring with its axis in the left-right direction, and biases the lock body 44 to the left. A through hole 45 is formed along the front-rear direction at the right end of the lock body 44. A square rod-shaped stopper 50 with its axis in the front-rear direction is inserted into this through hole 45. This stopper 50 is made of, for example, metal. The center of the stopper 50 in the front-rear direction is exposed inside the stay insertion hole 52 of the lock body 44. The exposed portion of the stopper 50 can be fitted into a notch 28 formed in the stay 24R on the right side of the headrest 18. This stopper 50 is integrated with the lock body 44 by, for example, insert molding.

The left end of the lock body 44 is formed with an operating portion 44B that protrudes to the left. This operating portion 44B is inserted into a through hole 58 formed in the cover 56. The cover 56 is manufactured, for example, by injection molding of resin, and is generally box-shaped with an opening on the right side. At both front-to-rear ends of the opening of the cover 56, there are formed locking grooves (not shown) into which locking claws 36A formed at both front-to-rear ends of the left end of the lock accommodating portion 36 fit, and the cover 56 is fixed to the lock accommodating portion 36 by this fit. The opening of the lock accommodating hole 40 is blocked by this cover 56.

As shown in Figures 4, 5 and 7, the lock body 44 has two rear convexities 46, one at the front and one at the rear, that protrude upward from the rear side (here, the right side) of the lock accommodating hole 40, and two front convexities 48, one at the front and one at the rear, that protrude upward from the front side (here, the left side) of the lock accommodating hole 40. The two rear convexities 46 are formed side by side in the front-rear direction at both ends in the front-rear direction at the right end of the upper surface of the lock body 44, and the two front convexities 48 are formed side by side in the front-rear direction at both ends in the front-rear direction at the left end of the upper surface of the lock body 44. These rear convexities 46 and front convexities 48 are formed, as an example, in a substantially hemispherical shape, with a spherical upper surface.

8 and 9, the lock accommodating hole 40 is formed in a tapered shape expanding in the vertical direction toward its opening side (here, the left side). This sets the punch taper of the slide mold when manufacturing the holder 32 by injection molding. Also, as shown in FIGS. 8 and 10, the protruding height of the front side convex portion 48 is set to be larger than the protruding height of the back side convex portion 46, and the vertical dimension of the lock body 44 is set to be larger on the front side of the lock accommodating hole 40 than on the back side of the lock accommodating hole 40. This makes it possible to make the gap S1 (see FIG. 8) between the upper surface of the lock accommodating hole 40 and the back side convex portion 46 equal to the gap S2 (see FIG. 8) between the upper surface of the lock accommodating hole 40 and the front side convex portion 48. These gaps S1 and S2 are adjusted by controlling the height dimension H1 (see FIG. 9) of the rear side of the lock accommodating hole 40, the height dimension H2 (see FIG. 9) of the front side of the lock accommodating hole 40, the height dimension h1 (see FIG. 10) of the portion of the lock 42 where the rear convex portion 46 is formed, and the height dimension h2 (see FIG. 10) of the portion of the lock 42 where the front convex portion 48 is formed. Note that for the sake of convenience, in FIG. 8 to FIG. 10, the taper of the lock accommodating hole 40 and the difference in the protruding height of the rear convex portion 46 and the front convex portion 48 are exaggerated.

In the headrest device 16 configured as described above, as shown in Figures 11 to 14, the left and right stays 24, 26 of the headrest 18 are inserted into the stay insertion holes 38L, 38R of the left and right headrest bushes 30L, 30R. Figure 11 shows a state in which the headrest 18 is restrained in the uppermost position relative to the seat back 14 and neither of the left nor right headrest bushes 30R are locked. When the headrest 18 is pushed down from this state to the position shown in Figure 12 relative to the seat back 14, the right headrest bush 30R locks.

Specifically, in the state shown in FIG. 12, the notch 28 formed in the right stay 24R faces the stopper 50 of the lock 42 provided on the right headrest bush 30R from the left side. As a result, the lock 42 is displaced to the left by the biasing force of the spring 54, and the stopper 50 fits into the notch 28. This restricts the upward displacement of the headrest 18 relative to the seat back 14. This restriction can be released by pressing the operating part 44B of the lock 42 to the right side. In addition, an inclined surface is set in the notch 28 so that the downward displacement of the headrest 18 relative to the seat back 14 is permitted even when the stopper 50 of the lock 42 is engaged with the notch 28, and the engagement between the stopper 50 and the notch 28 is released by the sliding of the inclined surface and the stopper 50.

When the headrest 18 is pushed down against the seat back 14 from the state shown in FIG. 12 to the state shown in FIG. 13, the left headrest bush 30L is locked with the headrest 18 positioned at the top of the height adjustment range. This restrains the headrest 18 at the top of the height adjustment range. When the headrest 18 is pushed down against the seat back 14 from the state shown in FIG. 13 to the state shown in FIG. 14, the left headrest bush 30L is locked with the headrest 18 positioned at the bottom of the height adjustment range. This restrains the headrest 18 at the bottom of the height adjustment range. When the headrest 18 is positioned in the range from the position shown in FIG. 13 to the position shown in FIG. 14, the right headrest bush 30R is unlocked, that is, the stopper 50 of the lock 42 is in contact with a portion of the right stay 24R other than the notch 28.

(Action and Effects)
Next, the operation and effects of this embodiment will be described.

In the headrest device 16 having the above configuration, the holder 32 of the headrest bush 30R is formed with a stay insertion hole 38R into which the stay 24R of the headrest 18 is inserted in the axial direction (up and down direction), and a lock accommodating hole 40 that opens to the left side and intersects with the stay insertion hole 38R is formed. The lock 42 inserted into the lock accommodating hole 40 is biased to the left side to engage with the stay 24R. The lock accommodating hole 40 is formed in a tapered shape that expands in the axial direction toward the opening side. This sets the punch taper when the holder 32 is manufactured by injection molding. The lock 42 has a rear-side protrusion 46 that protrudes upward (one side in the axial direction of the stay 24R) at the rear side of the lock accommodating hole 40, and a front-side protrusion 48 that protrudes upward at the front side of the lock accommodating hole 40. The protruding height of the front convex portion 48 is set to be greater than the protruding height of the rear convex portion 46, and the vertical dimension of the lock body 44 is set to be greater on the front side of the lock accommodating hole 40 than on the rear side of the lock accommodating hole 40. This effectively prevents the lock 42 from rattling inside the tapered lock accommodating hole 40, preventing the generation of abnormal noise.

In particular, in this embodiment, the speaker 22 is mounted on the headrest 18, and the mass of the headrest 18 is large, so that the inertial force acting on the headrest 18 due to vibrations during vehicle travel is large. In addition, under normal circumstances, the stopper 50 of the lock 42 is in contact with a portion of the right stay 24R other than the notch 28. Therefore, when the headrest 18 tries to displace relative to the seat back 14 due to the inertial force, the lock 42 rattles against the holder 32, causing abnormal noise. In this regard, in this embodiment, the gap S1 between the upper surface of the lock accommodating hole 40 and the rear convex portion 46, and the gap S2 between the upper surface of the lock accommodating hole 40 and the front convex portion 48 are optimally set, so that the rattle can be effectively prevented. Moreover, the rattle can be suppressed by pinpointing the accuracy of the protruding height of the rear convex portion 46 and the front convex portion 48, making it easy to manufacture.

In addition, in this embodiment, the rear side protrusion 46 and the front side protrusion 48 formed on the lock 42 protrude upward. This prevents the rear side protrusion 46 and the front side protrusion 48 from contacting the holder 32 under normal conditions, thereby preventing or suppressing deformation of the rear side protrusion 46 and the front side protrusion 48.

Furthermore, in this embodiment, the lock 42 has two rear-side protrusions 46 aligned in the front-rear direction and two front-side protrusions 48 aligned in the front-rear direction, which are aligned in the left-right direction, so that the four protrusions 46, 48 can effectively suppress rattling of the lock 42 relative to the holder 32. Moreover, it is easier to ensure the precision of each protrusion 46, 48 compared to, for example, a case in which the rear-side protrusion 46 and the front-side protrusion 48 are formed elongated in the front-rear direction.

In the above embodiment, the rear convex portion 46 and the front convex portion 48 of the lock 42 are separate convex portions, but this is not limited to this. For example, as in the first modified example shown in FIG. 15, the rear convex portion 46 and the front convex portion 48 may be configured to be connected to each other in the left-right direction.

In addition, in the above embodiment, the two rear-side protrusions 46 aligned in the front-rear direction are separate protrusions, and the two front-side protrusions 48 aligned in the front-rear direction are separate protrusions, but this is not limited to the above. For example, as in the second modified example shown in FIG. 16, the rear-side protrusions 46 and the front-side protrusions 48 may be formed in a bead shape (protrusion shape) that is long in the front-rear direction, and the shapes of the rear-side protrusions 46 and the front-side protrusions 48 can be changed as appropriate.

In addition, in the above embodiment, the rear convex portion 46 and the front convex portion 48 of the lock 42 are configured to protrude upward, but this is not limited thereto, and the rear convex portion 46 and the front convex portion 48 may be configured to protrude downward.

In addition, in the above embodiment, the lock 42 is configured to have a rear-side convex portion 46 and a front-side convex portion 48, but this is not limited thereto, and the lock 42 may be configured not to have a rear-side convex portion 46.

In addition, in the above embodiment, the headrest bush 30R is configured to prevent the speaker-equipped headrest 18 from falling out, but this is not limited thereto, and the headrest bush according to the present invention may be used to adjust the height of the headrest.

The present invention can be modified in various ways without departing from the spirit of the invention. It goes without saying that the scope of the invention is not limited to the above embodiment.

16 Headrest device 18 Headrest 22 Speaker (electrical device)
24L, 24R Stay 30R Headrest bush 32 Holder 38R Stay insertion hole 40 Lock accommodating hole 42 Lock 46 Back side protrusion 48 Front side protrusion

Claims (6)

a holder in which a stay insertion hole into which a stay of a headrest is inserted in an axial direction is formed, and a lock accommodating hole is formed, the lock accommodating hole opening to one side in a stay orthogonal direction perpendicular to the axial direction and intersecting with the stay insertion hole;
a lock that is inserted into the lock receiving hole and biased in a direction perpendicular to the stay to engage with the stay;
Equipped with
The lock accommodating hole is formed in a tapered shape expanding in the axial direction toward an opening side of the lock accommodating hole,
The lock has a front convex portion that protrudes to one side in the axial direction on the front side of the lock accommodating hole, and the axial dimension is set larger on the front side of the lock accommodating hole than on the rear side of the lock accommodating hole. The headrest bush according to claim 1, wherein one side in the axial direction is the upper side of the headrest. The headrest bush according to claim 1 or 2, wherein the lock has two of the front-side protrusions aligned in an alignment direction perpendicular to the axial direction and the stay-orthogonal direction. The headrest bush according to any one of claims 1 to 3, wherein the lock has a rear-side protrusion that protrudes to one side in the axial direction at the rear side of the lock receiving hole, and the protruding height of the front-side protrusion is set to be greater than the protruding height of the rear-side protrusion. The headrest bush according to claim 4, wherein the lock has two rear-side protrusions aligned in an alignment direction perpendicular to the axial direction and the stay-orthogonal direction, and two front-side protrusions aligned in the alignment direction. A pair of left and right headrest bushes are provided side by side in the left-right direction of the seat at an upper end of the seat back;
a headrest in which a pair of left and right stays extending from a main body on which electrical equipment is mounted are supported by the seat back via the left and right headrest bushes;
Equipped with
One of the left and right headrest bushes is the headrest bush described in any one of claims 1 to 5,
one of the left and right stays is inserted into the stay insertion hole of the holder provided in the one headrest bush,
The headrest device, wherein the one stay has only one notch formed therein, into which the lock of the one headrest bush can be fitted.