JP7491586B2 - Headrest stay and manufacturing method thereof - Google Patents

Description

The present invention relates to a headrest stay for supporting a headrest body and a manufacturing method thereof.

In automobiles, it is mandatory to provide a headrest on the seat to ensure the safety of the occupant. For example, as shown in FIG. 1 of Patent Document 1, a headrest of this kind is known that has a pair of vertical stays (stays 2 and 3 in the figure) attached to the lower side of the part that receives the occupant's head (headrest body). The headrest body is supported on the upper side of the seat back by inserting the lower ends of the vertical stays into stay holders (holders 6 and 7 in the figure) fixed to the upper part of the seat back. Positioning recesses (notched recesses 4 and 17 in the figure) are provided on the outer periphery of the vertical stays, and the headrest body is positioned in the height direction by engaging the locking member of the stay holder (stopper 13 in the figure) with this positioning recess. A support part equipped with this vertical stay is called a "headrest stay." Some headrest stays have positioning recesses provided in multiple levels, up and down, and the height of the headrest body can be adjusted by switching the positioning recesses that lock the locking member of the stay holder.

Japanese Utility Model Application Publication No. 03-072754

Incidentally, the positioning recess α of the vertical stay portion is processed by pressing the tip surface of a plate-shaped punch 100 against the outer peripheral surface of the pipe material P that will become the vertical stay portion, as shown in Figs. 1 and 2. However, when the positioning recess α is processed by this method, as shown in Fig. 2(c), a sagging portion _α2 is formed at the location along the upper edge and the lower edge of the positioning recess α, and the width _W1 of the flat portion _α1 becomes narrow. As already mentioned, the headrest body is positioned in the height direction by the locking member of the stay holder being locked to the positioning recess α, but the locking member is actually locked to the flat portion _α1 . Therefore, if the width _W1 of the flat portion _α1 is narrow, the locking member may come off the positioning recess α when an impact or vibration occurs to the vehicle body. In addition, the locking member may come off the positioning recess α when a downward force is applied to the headrest body. Furthermore, even if the engagement between the locking member and the positioning recess α does not come off, the headrest body and the headrest stay may become prone to rattling.

In addition, with the above method, when the tip surface of the plate-shaped punch 100 is pressed against the outer peripheral surface of the pipe material P, the excess material of the pipe material P may protrude around the positioning recess α on the outer peripheral portion of the pipe material P, causing a bulge to form in that area. This may make it difficult to engage the locking member with the positioning recess α, making it difficult to smoothly adjust the height of the headrest body.

The present invention has been made to solve the above problems, and provides a headrest stay that can secure a wide flat surface in the positioning recess and has a structure that makes it difficult for a locking member to come off the positioning recess. Another object of the present invention is to provide a headrest stay that is structured so that excess material of the pipe material that forms the vertical stay portion does not easily protrude from the outer periphery of the pipe material. Another object of the present invention is to provide a method for manufacturing this headrest stay.

The above issues are:
A method for manufacturing a headrest stay, in which a vertical stay portion for supporting a headrest body is formed of a pipe material, and a positioning recess for positioning the headrest body in a height direction is provided on an outer periphery of the vertical stay portion,
A tip surface of a plate-shaped punch is pressed against the outer peripheral surface of the pipe material to machine a positioning recess,
By using a punch having a pushing protrusion protruding from the tip surface,
An inward protrusion that protrudes inwardly toward the inside of the pipe material is formed at the back of the positioning recess,
and,
This problem is solved by providing a manufacturing method for a headrest stay, which is characterized in that slits are continuously formed in the wall of the pipe material at locations along the upper and lower edges of the positioning recess.

In this way, by forming a pushing convex portion on the tip surface of the punch that processes the positioning concave portion, it is possible to ensure a wide flat surface in the positioning concave portion (a flat surface on which a locking member such as a stay holder is locked).

In order to ensure a wide flat surface portion _α1 shown in Fig. 2(c), it is important to prevent the occurrence of the sagging portion _α2 shown in the same figure. As shown in Fig. ₂ (b), when the tip surface of the punch 100 is pressed against the outer circumferential surface of the pipe material P (vertical stay portion) and pressed, the sagging portion α2 is formed by drawing in a portion of the pipe material P that is located above or below the portion that the punch 100 hits in the direction in which the punch 100 is pressed. In this regard, as shown in Figs. 3 to 5 described later, by forming a pushing convex portion 101 on the tip surface of the punch 100, the portion of the pipe material P that the pushing convex portion 101 hits in the pipe material P is locally pushed deeper than the surrounding area. In other words, the punch 100 hits the pipe material P pipe wall not on a surface but on a line or a point, and pushes the pipe wall of the abutted portion deeper. As a result, the wall of the pipe material P begins to shear at locations above and below the pushing convex portion 101, and then, as the punch 100 is pushed further in, cuts are formed starting from the sheared portion and along the upper and lower edges of the positioning concave portion α. This is because the portions of the wall of the pipe material P that are located above and below the portion hit by the punch 100 are no longer pulled in in the direction in which the punch 100 is pushed in.

In this way, by suppressing the occurrence of the sagging portion _α2 and ensuring a wide flat portion _α1 , it is possible to prevent the locking member from coming off the positioning recess α even when an impact or vibration occurs to the vehicle body or when a downward force is applied to the headrest body. It is also possible to suppress rattling of the headrest body and the headrest stays.

When the positioning recess α is formed using a punch 100 having a pushing-in protrusion 101 on its tip surface, as shown in Fig. 5(c), an inward protrusion α3 that protrudes inwardly of the pipe material P is formed in the recess overlap section _S1 that overlaps the positioning recess α within the circumferential section S that circumferentially goes around the tube wall of the pipe material P. The presence of this inward protrusion _α3 allows _the flat surface section _α1 to appear over a wider range. It also becomes possible to engage the locking member more deeply with respect to the positioning recess α.

In addition, as described above, when slits are formed along the upper and lower edges of the positioning recess α, the tube wall of the pipe material P (vertical stay portion) is divided at the slits. Therefore, when the tip surface of the punch 100 is pressed against the outer periphery of the pipe material P, the excess material of the pipe material P cannot move to the periphery of the positioning recess α on the outer periphery of the pipe material P. Therefore, no excess bulge is formed around the positioning recess α. This makes it easier to smoothly adjust the height of the headrest body.

In addition, the above problem is
The vertical stay portion for supporting the headrest body is formed of a pipe material,
A headrest stay in which a positioning recess for positioning a headrest body in a height direction is provided on an outer periphery of a vertical stay portion,
A slit is continuously formed in the wall of the pipe material along the upper and lower edges of the positioning recess,
The above-mentioned problem can also be solved by providing a headrest stay, which is characterized in that an inward protrusion that protrudes toward the inside of the pipe material is formed at the back of the positioning recess.

This headrest stay can be suitably manufactured by the above manufacturing method. As already mentioned, a headrest stay in which slits are formed along the upper and lower edges of the positioning recess and an inward protrusion is formed at the back of the positioning recess ensures a wide flat surface in the positioning recess, allowing the locking member to be securely locked in the positioning recess. The locking member that is locked in the positioning recess is not limited to the one provided in the stay holder described above, but can also be one provided in the headrest body.

In the headrest stay of the present invention, it is preferable that the inward protrusion is provided in the left-right middle of the positioning recess, and that reverse protrusions that face in the opposite direction to the inward protrusion are formed on both the left and right sides of the inward protrusion. In this case, it is preferable that the reverse protrusions are curved in an arc shape. This makes it possible to more reliably shear (cut) the wall of the pipe material at locations along the upper and lower edges of the positioning recess, and ensure a wider flat surface.

In the headrest stay of the present invention, it is preferable that the depth from the outer circumferential surface of the pipe wall to the outer surface of the apex of the inwardly protruding portion is greater than the thickness of the pipe wall. This ensures that the flat surface is at least as thick as the pipe wall.

As described above, the present invention makes it possible to provide a headrest stay that can secure a wide flat surface in the positioning recess and that is structured so that the locking member is less likely to come off the positioning recess. It also makes it possible to provide a headrest stay that is structured so that excess material of the pipe material that forms the vertical stay is less likely to protrude from the outer periphery of the pipe material. It also makes it possible to provide a method for manufacturing this headrest stay.

FIG. 1 is a perspective view showing how positioning recesses are machined by a conventional method on the outer periphery of a pipe material that will become a vertical stay portion. FIG. 11 is a vertical cross-sectional view showing how positioning recesses are machined by a conventional method on the outer periphery of a pipe material that will become a vertical stay portion. 1 is a perspective view showing how positioning recesses are machined on the outer periphery of a pipe material that will become a vertical stay portion by the method of the present invention. FIG. 1 is a vertical cross-sectional view showing how positioning recesses are machined on the outer periphery of a pipe material that will become a vertical stay portion by the method of the present invention. FIG. 1 is a cross-sectional view showing how positioning recesses are machined by the method of the present invention on the outer periphery of a pipe material that will become a vertical stay portion. FIG. FIG. 2 is a perspective view showing the entire headrest stay of the present invention. FIG. 2 is a perspective view showing a state in which the headrest stay of the present invention is attached to a seat back. 7 is a cross-sectional view showing the headrest stay of the present invention cut along the line AA in FIG. 6. FIG. 11 is a perspective view showing a headrest stay according to another embodiment.

The headrest stay of the present invention will be described in more detail with reference to the drawings. The configuration described below is merely a preferred embodiment, and the technical scope of the present invention is not limited to the configuration described below. The headrest stay of the present invention can be modified as appropriate without departing from the spirit of the invention.

Figure 6 is a perspective view showing the entire headrest stay 10 of the present invention. As shown in Figure 6, this headrest stay 10 has a pair of left and right vertical stay portions 11 and a horizontal stay portion 12 that connects the upper ends of the pair of left and right vertical stay portions 11, and is shaped like an inverted "U" when viewed from the front. The headrest stay 10 may be integrated by subsequently joining different members (a member forming the left vertical stay portion 11, a member forming the right vertical stay portion 11, and a member forming the horizontal stay portion 12) together, but in this embodiment, it is formed by bending a single pipe material P.

The thickness of the tube wall of the pipe material P forming the headrest stay 10 (see thickness _T1 in FIG. 8 described later) is not particularly limited. However, if the tube wall of the pipe material P is made too thin, not only will the strength of the headrest stay 10 decrease, but it will also be difficult to ensure a flat surface portion _α1 (see FIG. 4(c) described later). For this reason, the thickness _T1 of the tube wall of the pipe material P is preferably 1 mm or more, and more preferably 2 mm or more. However, if the tube wall of the pipe material P is made too thick, the headrest stay 10 will become heavy. For this reason, the thickness _T1 of the tube wall of the pipe material P is usually set to 3 mm or less. In this embodiment, the thickness _T1 of the tube wall of the pipe material P is set to about 2.3 mm.

Figure 7 is a perspective view showing how the headrest stay 10 of the present invention is attached to the seat back 20. As shown in Figure 7, the headrest main body 30 (the portion that supports the user's head) is attached to the upper part of the headrest stay 10 (around the horizontal stay portion 12). Meanwhile, the lower part of the headrest stay 10 (the lower end side of the vertical stay portion 11) is attached to the seat back 20. A pair of left and right stay holders 40 are fixed to the upper part of the seat back 20. The headrest stay 10 is attached to the seat back 20 by inserting the vertical stay portions 11 into the stay insertion holes 41 provided in the stay holders 40.

The vertical stay portion 11 of the headrest stay 10 has a positioning recess α on its outer periphery. This positioning recess α is for positioning the headrest body 30 in the height direction (vertical direction). In this embodiment, the positioning recess α is provided in multiple stages in the lower section of the vertical stay portion 11. By engaging the locking member (not shown) of the stay holder 40 with the positioning recess α of the vertical stay portion 11 inserted into the stay insertion hole 41, the vertical stay portion 11 is immobilized relative to the stay holder 40, and the height (vertical position) of the headrest body 30 is maintained. In addition, by switching the positioning recess α that engages the locking member, the vertical position of the headrest stay 10 relative to the stay holder 40 can be changed, and the height of the headrest body 30 can be adjusted in stages. The arrangement pitch of the positioning recess α is usually in the range of 5 to 30 mm, and preferably in the range of 10 to 20 mm. In this embodiment, the arrangement pitch of the positioning recess α is set to about 13 mm.

The structure around the locking member of the stay holder 40 is not particularly limited, but typically a structure is adopted in which the locking member is advanced and retreated within the stay insertion hole 41 by operating a locking member operating means (not shown) such as a push button provided on the stay holder 40. In this embodiment, the locking member is elastically biased in a direction in which it advances into the stay insertion hole 41, and when the locking member operating means is not operated (when the push button is not pressed), the locking member advances into the stay insertion hole 41 and presses against the outer periphery of the vertical stay portion 11, making it possible to be locked in the positioning recess α, and when the locking member operating means is operated (when the push button is pressed), the locking member retreats from within the stay insertion hole 41 and is disengaged from the positioning recess α of the vertical stay portion 11.

The positioning recess α can be provided on both of the pair of left and right vertical stay parts 11. However, in this case, the operation of adjusting the height of the headrest body 30 becomes difficult. That is, when adjusting the height of the headrest body 30, it is necessary to move the headrest body 30 in the up and down direction while operating the locking member operating means of both of the pair of left and right stay holders 40. For this reason, in this embodiment, the positioning recess α is provided only on one of the vertical stay parts 11. In addition, a slip-out prevention recess β is provided near the lower end of the vertical stay part 11. This slip-out prevention recess β is intended to prevent the vertical stay part 11 inserted into the stay insertion hole 41 of the stay holder 40 from slipping out of the stay insertion hole 41 by being locked by the locking member of the stay holder 40. The slip-out prevention recess β is provided on both vertical stay parts 11.

As shown in Figures 3 to 5, each positioning recess α is formed by pressing the tip surface of a plate-shaped punch 100 against the outer circumferential surface of the pipe material P that will become the vertical stay portion 11. Figures 3 to 5 are views showing how the positioning recess α is machined on the outer circumferential surface of the pipe material P. Figure 3 is a perspective view of the side of the pipe material P where the positioning recess α is provided, viewed diagonally from above, Figure 4 is a vertical cross-sectional view of the pipe material P and the punch 100 cut along a plane including the center line _L1 of the pipe material P, and Figure 5 is a horizontal cross-sectional view of the pipe material P and the punch 100 cut along a plane perpendicular to the center line _L1 of the pipe material P. Figures 3(a), 4(a) and 5(a) show the state before the punch 100 is pressed against the outer peripheral surface of the pipe material P, Figures 3(b), 4(b) and 5(b) show the state after the punch 100 has been pressed against the outer peripheral surface of the pipe material P, and Figures 3(c), 4(c) and 5(c) show the state after the punch 100 has been retracted from the outer peripheral surface of the pipe material P.

The punch 100 is usually made of a high-hardness metal. Examples of such metal include die steel materials such as SKD materials. The width of the punch 100 is appropriately determined according to the diameter of the pipe material P, etc. The thickness (plate thickness) of the punch 100 is not particularly limited, but is usually in the range of 1 to 5 mm, and preferably in the range of 1 to 3 mm. In this embodiment, the thickness of the punch 100 is set to about 2 mm. The base end side (opposite the tip surface) of the punch 100 is attached to a drive mechanism (not shown). This drive mechanism performs the forward and backward movement of the punch 100 (the operation of pressing the punch 100 against the pipe material P and the operation of retracting the punch 100 from the pipe material P).

The punch 100 has a tip end face (the end face pressed against the outer peripheral surface of the pipe material P) with a pushing convex portion 101. As a result, as shown in FIG. 5B, when the tip end face of the punch 100 is pressed against the outer peripheral surface of the pipe material P, the portion of the pipe wall of the pipe material P that the pushing convex portion 101 hits is locally pushed deeper than the surrounding area. As the tip end face of the punch 100 abuts against the pipe material P and pushes into the pipe wall of the pipe material P, the pipe wall of the pipe material P begins to shear at the portions along the top and bottom of the pushing convex portion 101, and then, starting from the sheared portion, a cut is formed along the upper and lower edges of the positioning recess α. When the processing of the positioning recess α is completed, the portions along the upper and lower edges of the positioning recess α on the pipe wall of the pipe material P are cut over substantially the entire recess overlap section S ₁ (FIG. 5C). In other words, the pipe wall of the recessed overlap section _S1 (the pipe wall of the pipe material P) is connected to the surrounding pipe walls only at both ends of the recessed overlap section _S1 .

In this way, by forming the slits along the upper and lower edges of the positioning recess α, the sagging portion _α2 (see FIG. 2(c)) is less likely to be formed at the locations along the upper and lower edges of the positioning recess α. Therefore, as shown in FIG. 4(c), the flat surface portion _α1 can be secured widely. Therefore, the locking member of the stay holder 40 can be stably locked to the positioning recess α, and the locking member locked to the positioning recess α can be prevented from coming off the positioning recess α. Also, rattling of the headrest main body 30 and the headrest stay 10 can be suppressed. In addition, an inward convex portion α3 (FIGS. 5(b) and 5(c)) having a shape following the pushing convex portion ₁₀₁ is formed at the back of the positioning recess α. Therefore, not only is it easier to secure the flat surface portion _α1 more widely, but it is also possible to lock the locking member of the stay holder 40 deeper into the positioning recess α.

Furthermore, by forming slits along the upper and lower edges of the positioning recess α, excess material of the pipe material P is less likely to move to the periphery of the punch 100 when the tip face of the punch 100 is pressed against the outer circumferential surface of the pipe material P. This prevents excess bulges (bulges that may interfere with the engagement of the locking member with the positioning recess α) from being formed around the positioning recess α. This makes it easier to smoothly adjust the height of the headrest body 30.

Fig. 8 is a cross-sectional view showing the state in which the headrest stay 10 is cut along the A-A plane in Fig. 6. The depth _D1 (Fig. 8) from the outer circumferential surface of the pipe wall of the pipe material P to the outer surface of the apex of the inward convex portion _α3 is not particularly limited, but is preferably greater than the thickness _T1 of the pipe wall of the pipe material P (2.3 mm in this embodiment). This allows the flat portion _α1 to be secured wider. The depth _D1 is preferably secured to be 3 mm (1.3 times the thickness _T1 ) or more, and more preferably secured to be 4 mm (1.7 times the thickness _T1 ) or more. The upper limit of the depth _D1 is not particularly limited, but is usually about 6 to 7 mm.

The punch 100 (FIG. 5) is not particularly limited as long as it has a pushing convex portion 101 on its tip surface. In this embodiment, as shown in FIG. 5, curved recesses 102 are provided on both sides of the pushing convex portion 101 on the tip surface of the punch 100. As a result, when the punch 100 is pressed against the outer circumferential surface of the pipe material P, the punch 100 comes into contact with the outer circumferential surface of the pipe material P over a narrower range. Therefore, the wall of the pipe material P can be more reliably sheared (cut) at locations along the upper and lower edges of the positioning recess α, and a wider flat portion _α1 can be secured. Due to the curved recesses 102, as shown in FIG. 5(c), on both sides of the inward protrusion _α3 of the pipe material P, reverse protrusions _α4 facing in the opposite direction to the inward protrusion _α3 are formed in an arc-shaped cross section.

In this embodiment, as shown in FIG. 5(c), the pressing protrusions 103 are provided at both ends (further outside the curved recess 102) of the tip surface of the punch 100. This is because the above-mentioned cuts (cuts formed at locations along the upper and lower edges of the positioning recess α in the pipe wall of the pipe material P) can limit the movement of the excess material on the pipe wall of the pipe material P (the movement of the excess material that occurs when the tip surface of the punch 100 is pressed against the outer circumferential surface of the pipe material P) in the vertical direction, but cannot limit it in the circumferential direction of the pipe material P. For this reason, when the punch 100 is pressed against the pipe material P, the excess material on the pipe wall of the pipe material P moves to the left and right of the punch 100 (to the left and right of the positioning recess α), forming a bulge in that area, and there is a risk that the locking member of the stay holder 40 will not be properly locked in the positioning recess α. In this regard, by providing the above-mentioned pressing protrusion 103, the wall of the pipe material P can be pressed down by the pressing protrusion 103, so that the excess material on the wall of the pipe material P does not move to the left or right of the punch 100 (the left or right of the positioning recess α).

So far, we have described a case where the positioning recess α is provided in the lower section of the vertical stay portion 11 of the headrest stay 10, and the locking member of the stay holder 40 is locked in the positioning recess α. However, the location where the positioning recess α is provided is not limited to this. For example, as shown in Figure 9, the positioning recess α can be provided in multiple stages in the upper section of the vertical stay portion 11 of the headrest stay 10. Figure 9 is a perspective view showing a headrest stay 10 of another embodiment.

In the headrest stay 10 of FIG. 9, the headrest main body 30 (FIG. 7) is attached to the headrest stay 10 in a state in which it can be raised and lowered, and a locking member that locks into the positioning recess α is provided on the side of the headrest main body 30. This makes it possible to adjust the height of the headrest main body 30 by changing the up-down position of the headrest main body 30 relative to the headrest stay 10. In this way, the location where the positioning recess α is provided can be changed as appropriate depending on the specifications of the headrest. The positioning recess α in the headrest stay 10 of FIG. 9 can be processed in the same manner as already described.

In the headrest stay 10 of the present invention described above, the flat surface portion _α1 is widely secured in the positioning recess α, so that the locking member of the stay holder 40 is less likely to come off the positioning recess α. Therefore, even when the headrest stay 10 is subjected to impact or vibration, the headrest main body 30 can be maintained at a predetermined height. In addition, the excess material of the pipe material P forming the vertical stay portion 11 is less likely to protrude beyond the outer periphery of the pipe material P. Therefore, the height adjustment of the headrest main body 30 (height adjustment of the headrest stay 10 relative to the stay holder 40) can be smoothly performed.

The headrest stay 10 of the present invention can be used in various headrests, but is particularly suitable for use in headrests for seats in moving objects such as automobiles. This is because automobiles and other vehicles are expected to be subject to shocks and vibrations, and there is a significant advantage to using the headrest stay 10 of the present invention to prevent the locking member from coming off the positioning recess α.

REFERENCE SIGNS LIST 10 Headrest stay 11 Vertical stay portion 12 Horizontal stay portion 20 Seat back 30 Headrest body 40 Stay holder 41 Stay insertion hole 100 Punch 101 Push-in convex portion 102 Curved concave portion 103 Holding convex portion L ₁ Center of pipe material P Pipe material α Positioning concave portion α ₁ Flat portion α ₂ Drooping portion α ₃ Inward convex portion α ₄ Reverse convex portion β Recess for preventing slipping out

Claims (3)

The vertical stay portion for supporting the headrest body is formed of a pipe material,
A headrest stay in which a positioning recess for positioning a headrest body in a height direction is provided on an outer periphery of a vertical stay portion,
A slit is continuously formed in the wall of the pipe material along the upper and lower edges of the positioning recess,
An inward protrusion that protrudes inwardly from the pipe material is formed at a left-right intermediate portion at the rear of the positioning recess ,
At the back of the positioning recess, on both the left and right sides of the inward protrusion, a reverse protrusion curved in an arc shape and facing in the opposite direction to the inward protrusion is formed.
A headrest stay comprising:
2. The headrest stay according to claim 1 , wherein a depth from an outer circumferential surface of a pipe wall to an outer surface of an apex of the inwardly protruding portion is greater than a thickness of the pipe wall.
A method for manufacturing a headrest stay, in which a vertical stay portion for supporting a headrest body is formed of a pipe material, and a positioning recess for positioning the headrest body in a height direction is provided on an outer periphery of the vertical stay portion,
A tip surface of a plate-shaped punch is pressed against the outer peripheral surface of the pipe material to machine a positioning recess,
The punch includes:
A pushing protrusion protruding from the tip surface ;
A pair of pressing protrusions provided at both ends of the tip surface;
A pair of curved recesses provided between the pushing protrusions and the respective holding protrusions;
By using a material having
An inward protrusion that protrudes inwardly from the pipe material is formed in the left-right intermediate portion of the deepest portion of the positioning recess,
a pair of arc-shaped curved inverse convex portions facing in the opposite direction to the inward convex portion are formed on both the left and right sides of the inward convex portion at the back of the positioning concave portion;
and,
A method for manufacturing a headrest stay, comprising the steps of: continuously forming slits by cutting a wall of the pipe material at locations along upper and lower edges of the positioning recess.

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