JP2012025179A - Instrument panel beam and method of manufacturing the same - Google Patents

Abstract

Provided is an instrument panel beam that has sufficient lightness and high rigidity, can secure a large space inside an instrument panel, and can easily obtain the accuracy of the overall length, and such To provide a method capable of advantageously manufacturing an instrument panel beam.
An instrument panel beam disposed between a vehicle body member positioned on both sides in a vehicle width direction, extending in a vehicle width direction across a driver seat side and a passenger seat side, the passenger seat The portion arranged on the side is made of an aluminum pipe 14, while the portion arranged on the driver's seat side is composed of a steel pipe 12, and the aluminum pipe 14 is rubbed against one surface of the steel connecting plate 16. The aluminum pipe 14 and the steel pipe 12 are integrally connected to each other through the connecting plate 16 by being pressure-welded and friction-welding the steel pipe 12 to the other surface of the connecting plate 16. It was configured as follows.
[Selection] Figure 1

Description

  The present invention relates to an instrument panel beam and a manufacturing method thereof, and more particularly, to an improvement of an instrument panel beam disposed inside an instrument panel of an automobile and a method of advantageously manufacturing such an instrument panel beam.

  In general, an instrument panel beam (also referred to as a steering hanger beam, a cross car beam, etc.) is arranged inside the instrument panel of an automobile so as to extend in the vehicle width direction across the driver seat side and the passenger seat side. Thus, it is installed between vehicle body members located on both sides in the vehicle width direction. In this instrument panel beam, a mounting bracket or the like for mounting an air conditioning unit, an air bag, or the like is fixed to a portion disposed on the passenger seat side, and is disposed on the driver seat side. A steering column is attached to the part.

  By the way, the following performance is required for such an instrument panel beam. That is, (a) light weight that can contribute to improvement of fuel consumption by reducing the weight of the automobile, (b) rigidity that does not resonate the steering with respect to input vibration during idling, and (c) located on both sides in the vehicle width direction. High dimensional accuracy that can ensure the total length that can be securely attached to a specific vehicle body member (for example, an A pillar), and (d) a space as large as possible inside the instrument panel, In the instrument panel beam, design freedom is required that enables efficient storage of various members and parts such as harnesses, audio systems, air conditioning units, and airbags.

  Therefore, in recent years, instrument panel beams having various structures have been proposed in order to satisfy the above required performance. For example, in Japanese Patent Application Laid-Open No. 2001-253368 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-63628 (Patent Document 2), a portion disposed on the passenger seat side is made of an extruded shape made of an aluminum alloy having a small diameter. The part arranged on the driver's seat side is composed of a large-diameter aluminum alloy extruded shape, and a connector is interposed between such different-diameter extruded shapes, and they are screwed, etc. An instrument panel beam (instrument reinforcement) is proposed that is fixed by mechanical means. An instrument panel beam is also disclosed which is formed by connecting an extruded profile on the passenger seat side and an extruded profile on the driver seat side in an eccentric state.

  In these publications, it is made clear that the instrument panel beam disclosed therein has the following characteristics. (I) Since the entire instrument panel beam is formed of an aluminum alloy, a sufficient weight reduction can be achieved. (Ii) Since the driver seat side portion of the instrument panel beam has a large diameter, the rigidity of the driver seat side portion to which the steering column is attached can be ensured. (Iii) Since the passenger seat side portion of the instrument panel beam has a small diameter, a relatively large space on the passenger seat side inside the instrument panel can be secured. (Iv) By connecting the driver seat side portion and the passenger seat side portion in an eccentric state, the driver seat side portion and the passenger seat side portion are connected to the inner side of the instrument panel as compared with the case where the driver seat side portion and the passenger seat side portion are connected coaxially. The space of the part can be used effectively.

  However, as is well known, the Young's modulus of an aluminum alloy is about 1/3 that of steel. Therefore, when the diameter of the driver seat side portion is made larger than that of the passenger seat side portion and the instrument panel beam is made of all aluminum, the outer diameter of the driver seat side portion becomes extremely large. In this case, not only the advantage of weight reduction due to all-aluminum is greatly impaired, but also it becomes difficult to secure a large space in the driver's seat side portion inside the instrument panel. In addition, when the driver's seat side portion and passenger's seat side portion of the instrument panel beam are connected by a mechanical means such as screwing via a connector, a rust prevention treatment is required as a measure for joining different materials. From then on, extra work had to be done. In addition, in order to make the entire length of the instrument panel beam a desired length, screw insertion holes, female screw holes, etc. are accurately formed on the driver seat side portion and passenger seat side portion of the instrument panel beam and each of the connectors. It is necessary to provide the position with dimensional accuracy, which is not easy.

JP 2001-253368 A JP 2001-63628 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that it has sufficient light weight and high rigidity, and is large inside the instrument panel. It is an object of the present invention to provide an instrument panel beam that can secure a space and can easily obtain the accuracy of the overall length. Another object of the present invention is to provide a method capable of advantageously manufacturing such an instrument panel beam.

  And in this invention, in order to solve the problem concerning the instrument panel beam, it is arranged inside the instrument panel of the automobile so as to extend in the vehicle width direction across the driver seat side and the passenger seat side. An instrument panel beam installed between vehicle body members located on both sides in the vehicle width direction, the portion arranged on the passenger seat side is made of an aluminum pipe, while the portion arranged on the driver seat side is a steel pipe The aluminum pipe is friction-welded to one surface of the steel connecting plate and the steel pipe is friction-welded to the other surface of the connecting plate, so that the aluminum pipe and the steel pipe The gist of the instrument panel beam is characterized in that they are integrally connected via the connecting plate. In addition, the aluminum pipe said here is used as what includes both the aluminum pipe which consists of pure aluminum, and the aluminum pipe which consists of aluminum alloys. Hereinafter, they are used in the same meaning.

  According to one of the preferable aspects of the present invention, the steel pipe is configured to have a larger diameter than the aluminum pipe.

  According to one of desirable aspects of the present invention, the aluminum pipe and the steel pipe are integrally connected via the connecting plate in a state where they are located non-coaxially with each other.

  Further, according to one of the advantageous aspects of the present invention, the burr generated at the end of the aluminum pipe in contact with the connecting plate due to the friction welding of the aluminum pipe to one surface of the connecting plate, While forming as the thick part which enlarges the outer diameter of this contact side edge part, it will join to one side of this connection board.

  And in this invention, in order to solve the problem concerning the manufacturing method of the instrument panel beam, it extends inside the instrument panel of the automobile and extends in the vehicle width direction across the driver seat side and the passenger seat side. A method of manufacturing an instrument panel beam disposed between vehicle body members disposed on both sides in a vehicle width direction, comprising: (a) an aluminum pipe, a steel pipe, an outer diameter of the aluminum pipe, and the steel pipe; A step of preparing a steel connecting plate having a plate surface larger than the outer diameter, (b) a friction welding operation of the aluminum pipe with respect to one surface of the connecting plate, and with respect to the other surface of the connecting plate The method of manufacturing an instrument panel beam, comprising: simultaneously performing the friction welding operation of the steel pipe and integrally connecting the aluminum pipe and the steel pipe via the connecting plate. Also, also, to its gist.

  The connecting plate has a plate surface having a size that can draw a circle having a diameter that is 10 mm or more larger than the outer diameter of the aluminum pipe and 10 mm or more larger than the outer diameter of the steel pipe. ,preferable.

  Further, according to one of the desirable aspects of the present invention, the connecting plate having a plate surface larger than the outer diameter of the steel pipe is held unmovable and non-rotatable, and one of the connecting plates While placing the first backing member in contact with the surface, and placing the second backing member in contact with the other surface of the connecting plate, with respect to different positions on both sides of the connecting plate, The aluminum pipe is friction-welded to one surface of the connecting plate while the deformation of the connecting plate is prevented when the pressing force in the thickness direction is simultaneously applied, while the other of the connecting plate is The steel pipe is friction-welded to the surface at a position that is non-coaxial with the aluminum pipe.

  Furthermore, according to one of the preferred embodiments of the present invention, when the friction welding operation of the aluminum pipe with respect to one surface of the connection plate is performed, the outer periphery of the end portion on the contact side of the aluminum pipe with the connection plate An enclosure member having an enclosure surface positioned away from the surface, surrounding the corresponding contact end portion of the aluminum pipe, the outer peripheral surface of the contact end portion, and one surface of the connecting plate; A closed space is formed with the surrounding surface of the surrounding member, and burrs generated at the corresponding contact end portion of the aluminum by performing the friction welding operation of the aluminum pipe to the connecting plate are confined in the closed space. The burr is joined to one surface of the connecting plate by bringing it into contact with one surface of the connecting plate.

  Furthermore, according to one of the advantageous aspects of the present invention, the surrounding member is composed of a plurality of clamping members that sandwich the connecting plate, and the plurality of surrounding surfaces are provided on the plurality of clamping members. A plurality of divided surrounding surfaces are provided, and when the plurality of clamp members sandwich the connecting plate, the plurality of divided surrounding surfaces are combined to form the surrounding surface, and the aluminum pipe The abutting side end with the connecting plate is configured to be surrounded by the surrounding surface.

  According to another preferred aspect of the present invention, the surrounding surface of the surrounding member surrounds the contact-side end portion of the aluminum pipe that is in contact with one surface of the connecting plate. It will be comprised so that it may have a taper surface shape which becomes large diameter gradually toward the front-end | tip of this contact side edge part.

  That is, in the instrument panel beam according to the present invention, since the passenger seat side portion is composed of an aluminum pipe, sufficient lightness is advantageously ensured as compared to the instrument panel beam consisting entirely of steel pipes. To get. Further, in such an instrument panel beam, the rigidity required for the driver's seat side portion is not required for the passenger seat side portion, so that the aluminum pipe constituting such a passenger seat side portion can be made small in diameter. As a result, a sufficiently large space can be effectively secured in the passenger seat side portion inside the instrument panel where the small-diameter aluminum pipe is disposed. Furthermore, since the driver's seat side part is made of steel pipe, the rigidity of the driver's seat side part is increased without extremely increasing the outer diameter of the driver's seat side part, unlike the case where the entire instrument panel beam is made of aluminum pipe. It can be advantageously increased. And, since the outer diameter of the driver's seat side portion is not extremely increased as such, the space of the driver's seat side portion inside the instrument panel is also remarkably narrowed by the arrangement of the instrument panel beam. Can be advantageously avoided. In addition, when the outer diameter of the steel pipe is made somewhat larger than the outer diameter of the aluminum pipe to improve the rigidity of the steel pipe, the thickness can be reduced by increasing the outer diameter of the steel pipe. As a result, weight reduction of the steel pipe, and thus the entire instrument panel beam, can be expected.

  Further, in the instrument panel beam according to the present invention, the steel pipe constituting the driver's seat side portion and the aluminum pipe constituting the passenger seat side portion are friction-welded to both surfaces of the steel connecting plate, and the connecting plate It is connected integrally through. For this reason, at the time of friction welding to the connection plate of the steel pipe and the aluminum pipe, for example, by adjusting the pressure and the number of rotations to the connection plate of the steel pipe and the aluminum pipe to a preset value, The length of the pipe, and thus the length of the entire instrument panel beam, can be easily set to a desired length with high dimensional accuracy. And since the steel pipe and the aluminum pipe are each press-contacted to both surfaces of the connection board, the inner and outer diameters and plate thickness of each of these pipes can be set independently and appropriately. Further, the steel pipe and the aluminum pipe can be positioned coaxially or non-coaxially and positioned in an eccentric state simply by appropriately changing the friction welding location of each pipe with respect to the connecting plate. Moreover, the eccentric amount of a steel pipe and an aluminum pipe can be easily changed by changing the magnitude | size of a connection plate. In addition, no special rust prevention treatment is required.

  Therefore, in the instrument panel beam according to the present invention as described above, it is possible to advantageously realize a sufficient weight reduction and a high rigidity of a portion where rigidity is required. In addition, a sufficiently large space can be secured inside the instrument panel. In addition, the accuracy of the overall length dimension can be easily obtained, and the mounting accuracy to the vehicle body can be effectively improved.

  And in the instrument panel beam manufacturing method according to the present invention, the friction welding operation is simultaneously performed on both surfaces of the connecting plate of the small-diameter aluminum pipe and the large-diameter steel pipe. The instrument panel beam can be manufactured very easily and quickly.

It is a partially notched front explanatory view showing an embodiment of an instrument panel beam having a structure according to the present invention. It is II-II cross-section expansion explanatory drawing in FIG. It is explanatory drawing which shows the example of 1 process implemented when manufacturing the instrument panel beam shown by FIG. 1, Comprising: The state which hold | maintained the connection board with the clamp member is shown. FIG. 4 is a detailed explanatory view of the clamp member shown in FIG. 3. It is V arrow explanatory drawing in FIG. It is VI-VI surface explanatory drawing in FIG. It is explanatory drawing which shows the example of a process implemented following the process shown by FIG. 3, Comprising: The aluminum pipe and the steel pipe are simultaneously friction-welded with respect to both surfaces of a connection board, and are shown. FIG. 3 is a view corresponding to FIG. 1 showing another embodiment of an instrument panel beam having a structure according to the present invention. It is IX-IX cross-section expansion explanatory drawing in FIG. It is explanatory drawing which shows the example of 1 process implemented when manufacturing the instrument panel beam shown by FIG. 8, Comprising: The state which hold | maintained the connection board with the clamp member is shown. It is detail explanatory drawing of the upper side clamp member shown by FIG. It is XII arrow explanatory drawing in FIG. It is detail explanatory drawing of the lower side clamp member shown by FIG. It is XIV arrow explanatory drawing in FIG. It is XV-XV cross-sectional explanatory drawing in FIG. It is explanatory drawing which shows the example of a process implemented following the process shown by FIG. 10, Comprising: The aluminum pipe and the steel pipe are shown in the state simultaneously friction-welded with respect to both surfaces of a connection board.

  Hereinafter, in order to clarify the present invention more specifically, the configuration of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows an embodiment of an instrument panel beam having a structure according to the present invention in a front view including a partially cutaway view. As can be seen from FIG. 1, the instrument panel beam 10 of the present embodiment is such that the large-diameter first pipe 12 and the small-diameter second pipe 14 are located coaxially with respect to the connecting plate 16. These are integrally connected by friction welding and configured as one long pipe member.

  More specifically, the first pipe 12 constitutes a portion arranged on the driver's seat side in a state where the instrument panel beam 10 is arranged inside an instrument panel (not shown). Has a length approximately half of the vehicle width dimension of the automobile to be mounted. A steering column is attached to the first pipe 12 in such a state that the first pipe 12 is disposed inside the instrument panel. For this reason, the first pipe 12 needs to have rigidity sufficient not to resonate the steering due to vibration during idling. Therefore, the first pipe 12 is made of a steel material having high rigidity as a forming material. That is, here, the first pipe 12 is formed of a steel pipe. In addition, although the kind (material) of the steel pipe which comprises this 1st pipe 12 is not specifically limited, Generally, the 1st pipe 12 will be formed using the steel pipe for automotive structures. .

  Further, the second pipe 14 constitutes a portion arranged on the passenger seat side in a state where the instrument panel beam 10 is arranged inside an instrument panel (not shown), and the instrument panel beam 10 should be attached to the second pipe 14. It has a length approximately half of the vehicle width dimension of an automobile. A lightweight object such as a wire harness is attached to the second pipe 14 under the arrangement state inside the instrument panel. For this reason, the second pipe 14 does not need the rigidity required for the first pipe 12, and weight is given priority over that. Therefore, although the second pipe 14 has a lower rigidity than the steel material that forms the first pipe 12 as its forming material, it is pure aluminum or aluminum alloy (hereinafter collectively referred to simply as “lightweight”). (Referred to as aluminum). In other words, here, the second pipe 14 is composed of an aluminum pipe (including a pure aluminum pipe and an aluminum alloy pipe; hereinafter, they are used in the same meaning). In addition, although the kind (material) of the aluminum pipe which comprises this 2nd pipe 14 is not specifically limited, 3000 series, 5000 series, 6000 series, and 7000 series aluminum alloys of JIS name are used suitably. It is done.

  Furthermore, the second pipe 14 made of such an aluminum pipe has a small diameter in order to further improve the light weight and to secure a large space inside the instrument panel when arranged inside the instrument panel. ing. On the other hand, the first pipe 12 has a large diameter for the purpose of obtaining sufficient rigidity as described above, and has a larger diameter than the second pipe 14 in the present embodiment. Thus, since the first pipe 12 has a large diameter, the wall thickness is not increased more than necessary to improve the rigidity. Thereby, the weight of the first pipe 12 is made as small as possible. Note that the first pipe 12 does not necessarily have a larger diameter than the second pipe 14 as long as the first pipe 12 can ensure rigidity larger than that of the second pipe 14.

  The diameters (outer diameters) and wall thickness dimensions of the first pipe 12 and the second pipe 14 are not particularly limited, and are appropriately determined according to the rigidity and light weight required for the instrument panel beam 10. Preferably, the dimensions are as follows. That is, the outer diameter of the first pipe 12 made of a steel pipe is preferably set to a value in the range of 40 to 70 mm. The wall thickness is generally a value in the range of 1.8 to 3.2 mm. This is because, when the outer diameter of the first pipe 12 is less than 40 mm or the wall thickness is less than 1.8 mm, it may be difficult to ensure the desired rigidity required for the first pipe 12. Because there is. In addition, when the outer diameter of the first pipe 12 exceeds 70 mm or when the wall thickness exceeds 3.2 mm, the first pipe 12 is enlarged, so that the inner space of the instrument panel becomes the first pipe 12. This is because there is a high possibility that the fuel consumption efficiency of the automobile to which the instrument panel beam 10 is mounted will be reduced due to excessive removal of the instrument panel beam 10 or excessive weight of the instrument panel beam 10 as a whole.

  The outer diameter of the second pipe 14 made of an aluminum pipe is preferably in the range of 25 to 55 mm. The wall thickness is generally a value in the range of 1.8 to 4.0 mm. This is because when the outer diameter of the second pipe 14 is less than 25 mm or when the wall thickness is less than 1.8 mm, the strength of the second pipe 14 may be extremely low. On the other hand, when the outer diameter of the second pipe 14 exceeds 55 mm or when the wall thickness exceeds 4.0 mm, the second pipe 14 is enlarged, so that the inner space of the instrument panel becomes the second pipe 14. This is because there is a high possibility that the fuel consumption efficiency of the automobile to which the instrument panel beam 10 is mounted will be reduced due to excessive removal of the instrument panel beam 10 or excessive weight of the instrument panel beam 10 as a whole.

  Note that the rigidity, strength, or lightness required for the instrument panel beam 10 may be variously changed depending on the type of automobile on which the instrument panel beam 10 is mounted. Therefore, the preferable range of the outer diameter and thickness of the first pipe 12 and the second pipe 14 as described above, and the preferable range of the thickness of the connecting plate 16 to be described later also depend on the type of the vehicle on which the instrument panel beam 10 is mounted. It may be changed as appropriate.

  On the other hand, as shown in FIGS. 1 and 2, the connecting plate 16 as a whole has a substantially circular flat plate shape having an outer diameter that is slightly larger than the outer diameter of the end of the first pipe 12. Moreover, the 1st and 2nd flat surfaces 17a and 17b are each provided in the part located in the both sides of a diameter direction among the outer peripheral surfaces of the connection board 16 so that it may mutually extend in parallel. The first pipe 12 made of a steel pipe is friction-welded to one surface of the connecting plate 16, and the second pipe 14 made of an aluminum pipe is friction-welded to the other surface.

  Such a connecting plate 16 is made of steel of the same material as that of the first pipe 12 or pure aluminum of the same material as that of the second pipe 14 in consideration of the joining property with the first pipe 12 and the second pipe 14. It is desirable that it is made of an aluminum alloy. However, when the connecting plate 16 is made of aluminum, the end of the first pipe 12 bites into the connecting plate 16 due to the applied pressure during friction welding of the first pipe 12 made of a steel pipe having a hardness higher than that of the connecting plate 16. Therefore, there is a high possibility that sufficient bonding cannot be performed. For this reason, in this invention, the connection plate 16 is comprised with the steel material. Although the kind of steel material used for the forming material of this connection board 16 is not specifically limited, The thing of the same kind as the steel material which forms the 1st pipe 12 is used suitably. Thereby, more sufficient bondability or bonding strength can be ensured.

  The connecting plate 16 has an outer diameter of the first pipe 12 and the second pipe so that the first pipe 12 and the second pipe 14 located on the same axis can be reliably friction-welded to both surfaces. As long as it has a larger plate surface than the larger one of the outer diameters of 14 (here, the outer diameter of the first pipe 12), the specific size and shape are not specified at all. . However, in order to prevent an increase in the weight of the connecting plate 16 and thus the entire instrument panel beam 10, it is as small as possible and is close to the cross-sectional shape of the first and second pipes 12, 14 having a large outer diameter. The shape is desirable. On the other hand, when the first pipe 12 and the second pipe 14 are friction-welded to the connecting plate 16, the connecting plate 16 is securely held so that the friction welding operation can be performed smoothly. It is preferable that the surface has a size capable of drawing a circle having a diameter 10 mm or more larger than the larger one of the outer diameter of the first pipe 12 and the outer diameter of the second pipe 14. Accordingly, in the present embodiment, as is apparent from FIG. 2, the connecting plate 16 is a circle having a diameter R which is 10 mm or more larger than the outer diameter r of the first pipe 12 (indicated by a two-dot chain line in FIG. 2). It has a substantially disk shape with a plate surface that can be drawn.

  The thickness (plate thickness) of the connecting plate 16 is not particularly limited, but is preferably 5 to 15 mm. This is because if the thickness of the connecting plate 16 is less than 5 mm, it is too thin and the rigidity or strength is insufficient. Therefore, the first pipe 12 made of steel pipe is deformed by the applied pressure during friction welding. This is because there is a risk that sufficient bonding cannot be performed. Further, when the thickness of the connecting plate 16 exceeds 15 mm, the connecting plate 16 is too thick and the weight of the connecting plate 16 becomes excessive, and the possibility that the weight of the entire instrument panel beam 10 is significantly increased is increased.

  On the joint surface of the connecting plate 16 with the second pipe 14, a burr 18 formed at the joint side end of the second pipe 14 forms a thick portion that gives a tapered outer peripheral surface, It is joined. That is, since the second pipe 14 made of an aluminum pipe has a lower hardness than the connection plate 16 made of steel, the second pipe 14 is in contact with the end of the contact side (joining side) with the connection plate 16 at the time of friction welding to the connection plate 16. As a result, burrs 18 continuously extending in the circumferential direction over the entire circumference are inevitably generated. In this embodiment, the burr 18 is formed so as to increase the diameter of the contact end portion of the second pipe 14 and is joined to the connecting plate 16. In addition, the shape of the outer peripheral surface of the burr 18 is a tapered surface shape that gradually increases in diameter toward the connecting plate 16 side in a form larger than the outer diameter of the contact end portion of the second pipe 14. It is controlled to be. The bonding strength of the second pipe 14 to the connecting plate 16 is more effectively enhanced by the bonding of the burr 18 to the connecting plate 16. Further, when the instrument panel beam 10 is installed in a limited space inside the instrument panel, parts and members such as a wire harness attached to the second pipe 14 interfere with the burr 18, and these parts and members It is difficult to install the burrs, or those parts and members may be damaged due to contact with, for example, the pointed burr 18 part, because the outer peripheral surface shape of the burr 18 is controlled to be a tapered surface shape. Can be advantageously prevented.

  Although not shown, the instrument panel beam 10 having the above-described structure places the first pipe 12 on the driver's seat side inside the instrument panel as in the conventional case, while the second pipe 14 Is positioned on the passenger seat side, and is arranged to extend in the vehicle width direction across the driver seat side and the passenger seat side. And under such an arrangement state, it is constructed between vehicle body members, such as an A pillar (front pillar), located on both sides in the vehicle width direction.

  Here, the instrument panel beam 10 having the above-described structure is manufactured as follows, for example.

  That is, first, as shown in FIG. 3, the connecting plate 16 is sandwiched between the upper clamp member 20 and the lower clamp member 22 in the vertical direction. The upper clamp member 20 and the lower clamp member 22 have the same structure, and both move in the vertical direction (the direction of the white arrow in FIG. 3) by the operation of an actuator such as a hydraulic cylinder (not shown). It is possible.

  More specifically, as shown in FIGS. 4 and 5, the upper clamp member 20 includes a metal clamp portion 24 and a connecting rod 26 that connects the clamp portion 24 to an actuator (not shown). . The clamp portion 24 has a substantially inverted L shape as a whole. And it exhibits a thick flat plate shape extending in the horizontal direction, and on the upper surface, vertically downward from one end portion of the substrate portion 28 connected to the connecting rod 26 and the extending direction of the substrate portion 28 (left-right direction in FIG. 4). It has a thick flat plate-like contact portion 30 that protrudes toward it.

  A concave portion 32 is formed in the intermediate portion of the lower surface of the substrate portion 28 of the clamp portion 24 in the extending direction. And the bottom surface of this recessed part 32 is made into the clamp surface 34 which has a shape corresponding to the 1st flat surface 17a of the said connection board 16, and the outer peripheral surface part located in the circumferential direction both sides on both sides of it .

  Further, a groove portion 40 having a substantially semicircular cross section is formed at the center of the lower surface of the contact portion 30. This groove portion 40 has an inner peripheral surface portion on the opening side that opens toward the right side in FIG. 4 (the end portion opposite to the end portion where the contact portion 30 of the substrate portion 28 is formed). On the other hand, the inner peripheral surface portion on the opening side that opens toward the left side in FIG. 4 (the end portion side where the contact portion 30 of the substrate portion 28 is formed) is defined as a divided guide surface 44. Yes.

  Furthermore, the divided surrounding surface 42 has a half-tapered surface shape that gradually increases in diameter toward the right side of FIG. Further, the minimum radius of the divided surrounding surface 42 is the same as or slightly larger than the radius of the outer peripheral surface of the second pipe 14 (1/2 of the outer diameter). The divided guide surface 44 has a half-tapered surface shape that gradually increases in diameter toward the left side of FIG. The minimum radius of the guide surface 44 is also the same as or slightly larger than the radius of the outer peripheral surface of the second pipe 14 (1/2 of the outer diameter). The divided surrounding surface 42 is set so that the taper angle of the half tapered surface shape is larger than that of the divided guide surface 44.

  On the other hand, the lower clamp member 22 also has a metal clamp portion 24 and a connecting rod 26 that connects the clamp portion 24 to an actuator (not shown). The lower clamp member 22 has exactly the same structure as the upper clamp member 20 just by turning the upper clamp member 20 upside down. Therefore, the description of the clamp portion 24 of the lower clamp member 22 is omitted here.

  3 and 6, the connecting plate 16 is disposed so that the first and second flat surfaces 17a and 17b are positioned above and below, respectively, and the upper and The upper clamp member 20 and the lower clamp member 22 respectively disposed on the lower side are moved downward or upward by an actuator (not shown). Thus, the upper end side portion including the first flat surface 17a and the lower end side portion including the second flat surface 17b of the connecting plate 16 are connected to the clamp portions 24 and 24 (substrate portions) of the upper and lower clamp members 20 and 22, respectively. 28 and 28) are respectively housed and held in the recesses 32 and 32 provided in the space.

  Based on the operation of an actuator (not shown), the clamp surfaces 34 and 34 of the recesses 32 and 32 of the upper and lower clamp members 20 and 22 are pressed against the connecting plate 16, respectively. As a result, the connecting plate 16 is sandwiched between the upper clamp member 20 and the lower clamp member 22. The connecting plate 16 cannot be displaced, and cannot be rotated by contact and engagement of the flat surfaces 17a and 17b with the clamp surfaces 34 and 34.

  Further, in such a state that the connecting plate 16 is clamped by the upper and lower clamp members 20 and 22, the tip surfaces of the contact portions 30 and 30 of the upper and lower clamp members 20 and 22 are brought into pressure contact with each other. Thereby, the insertion hole 45 is formed in each groove part 40 and 40 provided in each contact part 30 and 30 between those front end surfaces.

  An inner peripheral surface portion on one opening portion (opening portion on the right side in FIG. 3) side of the insertion hole 45 is an surrounding surface 46 including the divided surrounding surfaces 42 and 42. Further, an inner peripheral surface portion on the other opening portion (opening portion on the left side in FIG. 3) side of the insertion hole 45 is a guide surface 48 including the respective divided guide surfaces 44 and 44. The surrounding surface 46 has a tapered surface shape that gradually increases in diameter toward one opening side of the insertion hole 45. The guide surface 48 has a tapered surface shape that gradually increases in diameter toward the other opening side of the insertion hole 45. Further, the surrounding surface 46 and the guide surface 48 exhibiting the tapered surface shape have a minimum diameter that is the same as or slightly larger than the outer diameter of the second pipe 14.

  Thus, the connecting plate 16 sandwiched between the upper and lower clamp members 20 and 22 is exposed to the outside at portions other than the outer peripheral portions of one surface and the other surface in the thickness direction.

  When the connecting plate 16 is sandwiched between the upper and lower clamp members 20 and 22 so as to be in the holding state as described above, as shown in FIG. At the front end surface on the side, it is brought into contact with and positioned at the center of the exposed portion of one surface of the connecting plate 16 to the outside. At the same time, one end of the second pipe 14 in the axial direction is guided by the guide surface 48 and is inserted into the insertion hole 45, and at the tip end surface, the central portion of the other surface of the connecting plate 16 is inserted. Abut and position.

  Thus, the first pipe 12 and the second pipe 14 are positioned coaxially via the connecting plate 16. Moreover, at this time, the surrounding surface 46 formed between each contact part 30 and 30 of the 1st and 2nd clamp members 20 and 22 is the contact side edge part to the connection plate 16 of the 2nd pipe 14, Enclose it at a position spaced apart in the radial direction. Then, the outer peripheral surface of the contact side end of the second pipe 14 to the connecting plate 16, the contact surface of the connecting plate 16 with the contact end of the second pipe 14, and the surrounding surface 46 A closed space 50 is formed therebetween. As is clear from this, in this embodiment, the upper clamp member 20 and the lower clamp member 22 each having the divided surrounding surface 42 constitute an enclosing member.

  Thereafter, the first pipe 12 and the second pipe 14 are rotated around the axis while being pressed against both surfaces of the connecting plate 16 by a pressurizing device and a rotating device (not shown). Thus, the friction welding operation of the first pipe 12 with respect to one surface of the connecting plate 16 and the friction welding operation of the second pipe 14 with respect to the other surface of the connecting plate 16 are simultaneously performed. At this time, as shown by a two-dot chain line in FIG. 7, burrs 18 are inevitably generated at the abutting side end of the second pipe 14 made of an aluminum pipe. The burr 18 is confined and filled in the closed space 50. Then, such a burr 18 is pressed against the connecting plate 16 while rotating together with the end surface of the second pipe 14 in contact with the connecting plate 16. As a result, the burr 18 is joined to the connecting plate 16 and formed into a shape corresponding to the closed space 50, and its outer peripheral surface is formed into a tapered surface shape corresponding to the surrounding surface 46. Then, the friction welding operation of the first pipe 12 and the friction welding operation of the second pipe 14 are completed at the same time or with a time difference, so that the target instrument panel beam having the structure shown in FIG. 10 is obtained.

  In addition, although the implementation conditions of the friction welding operation with respect to the connection part 16 of the 1st pipe 12 and the 2nd pipe 14 are not specifically limited, in implementing these friction welding operations, the 1st pipe 12 and the 2nd pipe 14 is preferably set to 80 to 150 MPa, and the number of rotations of the first pipe 12 and the second pipe 14 is preferably set to 600 to 1200 rpm. This is because when the pressure applied to each pipe 12, 14 is less than 80 MPa or when the rotational speed is less than 600 rpm, the joining strength of each pipe 12, 14 to the connecting plate 16 may be insufficient. Because there is. Moreover, it is because the 2nd pipe 14 which consists of an aluminum pipe may deform | transform in the middle of friction welding operation, if the applied pressure of each pipe 12 and 14 becomes a big value exceeding 150 MPa. Furthermore, even if the pipes 12 and 14 are rotated at a rotational speed exceeding 1200 rpm, the performance of the joint joint such as the joint strength is not expected to be improved so much, but on the contrary, the cost required for the friction welding is increased. Because. In addition, when the second pipe 14 made of an aluminum pipe is rotated at a rotational speed exceeding 1200 rpm, the temperature of the connection portion between the second pipe 14 and the connecting plate 16 becomes too high, which may make joining difficult. Even there. When the friction welding operation is performed on the connecting portion 16 of the first pipe 12 and the second pipe 14, for example, the amount of decrease in the length of each pipe 12, 14 due to the friction welding operation becomes a preset value. The execution conditions such as the applied pressure and the number of rotations are appropriately set so that the entire length of the instrument panel beam 10 becomes a desired length.

  Thus, in the instrument panel beam 10 of the present embodiment, the first pipe 12 that is disposed on the driver's seat side portion inside the instrument panel and to which the steering column is attached is made of a large-diameter steel pipe, The 2nd pipe 14 arrange | positioned at a passenger seat side part is comprised with the small diameter aluminum pipe. Therefore, the rigidity of the instrument panel beam 10 as a whole can be sufficiently increased while the rigidity of the instrument panel beam 10 is sufficiently ensured, and steering resonance due to input vibration during idling or the like can be effectively prevented. It is also possible to secure the space inside the instrument panel in as large a size as possible. Furthermore, the thickness of the first pipe 12 can be reduced as much as the diameter of the first pipe 12 made of a steel pipe is increased. Also by this, the weight reduction of the 1st pipe 12 and by extension, the instrument panel beam 10 whole can be anticipated.

  Moreover, the length of the entire instrument panel beam 10 can be set to a desired length only by arbitrarily setting conditions such as the pressure and the number of revolutions when the friction welding is performed on both surfaces of the connecting plate 16 of the first pipe 12 and the second pipe 14. The length can be easily and accurately finished. As a result, it is possible to advantageously improve the accuracy of mounting the instrument panel beam 10 to the vehicle body.

  By manufacturing the instrument panel beam 10 of the present embodiment by the above-described method, the manufacturing process of the instrument panel beam 10 can be advantageously shortened and made efficient.

  Next, FIG. 8 shows another embodiment of an instrument panel beam having a structure according to the present invention. In addition, regarding the instrument panel beam 52 and the manufacturing method thereof according to the present embodiment, members and parts having the same structure as the instrument panel beam 10 according to the first embodiment will be further described. About the member which has the same structure as the member used, the detailed description is abbreviate | omitted by attaching | subjecting the code | symbol same as FIG. 1 thru | or FIG.

  That is, as apparent from FIG. 8, the instrument panel beam 52 of the present embodiment is also arranged on the passenger seat side and the large-diameter first pipe 12 made of a steel pipe arranged on the driver seat side inside the instrument panel. A small-diameter second pipe 14 made of an aluminum pipe is friction-welded to a steel connecting plate 54 to form a single longitudinal pipe member. Here, the first pipe 12 and the second pipe 14 are arranged non-coaxially with each other.

  Further, as shown in FIG. 9, the connecting plate 54 has a substantially oval shape as a whole. The first pipe 12 made of a steel pipe is friction-welded at a position deviated from the center in the long axis direction to one side on one surface of the connecting plate 54. On the other side, the second pipe 14 made of an aluminum pipe is friction-welded at a position deviated from the center in the length direction to the side opposite to the side to which the first pipe 12 is joined. . The first and second flat surfaces 17a and 17b are provided on the outer peripheral surface of the connecting plate 54 at both ends in the major axis direction so as to extend in parallel with each other. The connecting plate 54 has a minor axis length that is larger than the outer diameter of the large-diameter first pipe 12 (for example, a dimension that is 10 mm or more larger), and the first flat surface 17a. The distance from the outer peripheral surface of the second pipe 14 to the outer peripheral surface of the second pipe 14 and the distance from the second flat surface 17b to the outer peripheral surface of the first pipe 12 are each larger than a predetermined amount (for example, larger than 5 mm). .

  Even in such an instrument panel beam 52, the burrs 18 formed on the outer peripheral surface of the end of the second pipe 14 in contact with the connecting plate 54 are joined to the connecting plate 54. Moreover, the outer peripheral surface of such a burr | flash 18 is made into the taper surface shape which becomes large diameter toward the connection board 54 side, and is formed as a thick part of the contact side edge part of the 2nd pipe 14. As shown in FIG.

  And such an instrument panel beam 52 is manufactured as follows, for example.

  That is, first, as shown in FIG. 10, the connecting plate 54 is sandwiched in the vertical direction between the upper clamp member 56 and the lower clamp member 58. Each of the upper and lower clamp members 56 and 58 includes a substrate portion 28 extending in the horizontal direction and a contact portion 30 integrally projecting from one end portion in the extending direction of the substrate portion 28. Have. The substrate portions 28 and the abutting portions 30 of the upper and lower clamp members 56 and 58 are the substrate portions 28 of the upper and lower clamp members 20 and 22 used when the instrument panel beam 10 according to the first embodiment is manufactured. And the contact portion 30 has the same structure. That is, each substrate portion 28 is provided with a recess 32 having a clamp surface 34. Each contact portion 30 is provided with a groove portion 40 having a divided surrounding surface 42 and a divided guide surface 44.

  11 and 12, the backing portion 60 is opposed to the contact portion 30 at the end of the upper clamp member 56 opposite to the contact portion 30 formation side in the substrate portion 28. In such a state, it projects integrally downward. The backing portion 60 has a thick flat plate shape, and a surface facing the contact portion 30 is a flat backing surface 62 extending in parallel with the contact portion 30.

  On the other hand, as shown in FIG. 13 and FIG. 14, the lower clamp member 58 has a protruding portion whose contact portion 30 is sufficiently longer than the contact portion 30 of the upper clamp member 56. The intermediate portion in the length direction of the contact portion 30 is a backing portion 60, and one side in the thickness direction of the backing portion 60 (the end where the contact portion 30 of the substrate portion 28 is formed). The surface on the side opposite to the part) is the backing surface 62.

  10 and 15, the upper end side portion including the first flat surface 17a of the connecting plate 54 enters the recess 32 of the upper clamp member 56, and the lower end including the second flat surface 17b. With the portion protruding into the recess 32 of the lower clamp member 58, the connecting plate 16 is sandwiched between the clamp surface 34 of the upper clamp member 56 and the clamp surface 34 of the lower clamp member 58. As a result, similarly to the manufacture of the instrument panel beam 10 of the first embodiment, the connecting plate 54 is not displaceable and rotates under the clamping state between the upper clamp member 56 and the lower clamp member 58. It is considered impossible.

  Further, when the connecting plate 54 is sandwiched between the upper and lower clamp members 56 and 58, it is inserted between the tip surfaces of the contact portions 30 and 30 of the upper and lower clamp members 56 and 58. A hole 45 is formed in each groove 40, 40. And the inner peripheral surface part of the opening side in the backing surface 62 of such an insertion hole 45 is made into the surrounding surface 46 which consists of each division | segmentation surrounding surface 42 and 42, On the other hand, it is the opposite side to the backing surface 62 An inner peripheral surface portion on the opening side that opens on this surface is a guide surface 48 made up of the divided guide surfaces 44, 44. Accordingly, the central portion of the upper portion of the contact surface of the connecting plate 54 with respect to the contact portion 30 of the upper clamp member 56 is exposed to the outside through the insertion hole 45. Further, the lower part of the surface opposite to the contact surface of the connecting plate 54 is exposed to the outside.

  Here, the portion corresponding to the surface exposed to the outside through the insertion hole 45 of the connecting plate 54 on the surface opposite to the thickness direction is the backing surface 62 of the backing portion 60 of the upper clamp member 56. Is backed up by the backing unit 60. In addition, the portion corresponding to the surface exposed on the opposite side in the thickness direction with respect to the exposed portion of the lower portion of the connecting plate 54 contacts the backing surface 62 of the backing portion 60 of the lower clamp member 58. And backed up by the backing unit 60. As is clear from this, in the present embodiment, the first backing member and the second backing member are composed of the upper clamp member 56 and the lower clamp member 58 each having the backing portion 60. Each is composed.

  Then, when the connecting plate 54 is sandwiched between the upper and lower clamp members 56 and 58 so as to be in the above-described state, as shown in FIG. The front end surface of the connecting plate 54 is brought into contact with the central portion in the width direction of the lower portion exposed to the outside of one surface of the connecting plate 54. At the same time, one end of the second pipe 14 in the axial direction is guided by the guide surface 48 while being inserted into the insertion hole 45 and exposed to the outside of the other surface of the connecting plate 54 at the tip end surface. The upper part is in contact with and positioned at the center in the width direction.

  As a result, the first pipe 12 and the second pipe 14 are positioned non-coaxially, in other words, eccentrically, via the connecting plate 54. Further, at this time, the surrounding surface 46 formed between the contact portions 30 and 30 of the upper and lower clamp members 56 and 58 has an end portion on the contact side of the second pipe 14 with respect to the connecting plate 54. Enclose at a radially spaced position. Then, the outer peripheral surface of the contact side end of the second pipe 14 to the connection plate 54, the contact surface of the connection plate 54 with the contact side end of the second pipe 14, and the surrounding surface 46 A closed space 50 is formed therebetween. As is clear from this, even in the present embodiment, the surrounding member is constituted by the upper clamping member 56 and the lower clamping member 58 each having the divided surrounding surface 42.

  Thereafter, the first pipe 12 and the second pipe 14 are rotated around the axial center while simultaneously pressing the first pipe 12 and the second pipe 14 against both surfaces of the connecting plate 54 by using a pressurizing device and a rotating device (not shown). Thus, the friction welding operation of the first pipe 12 with respect to one surface of the connecting plate 54 and the friction welding operation of the second pipe 14 with respect to the other surface of the connecting plate 54 are simultaneously performed. At this time, as indicated by a two-dot chain line in FIG. 16, the burr 18 generated at the abutting side end of the second pipe 14 made of an aluminum pipe is formed in the closed space 50 as in the first embodiment. It is confined and joined to the connecting plate 54, and is shaped into a shape corresponding to the closed space 50, and its outer peripheral surface has a tapered surface shape corresponding to the surrounding surface 46. Then, when the friction welding operation of the first pipe 12 and the friction welding operation of the second pipe 14 are finished at the same time or after a time difference, the target instrument panel beam having the structure as shown in FIG. 52 is obtained. In addition, the suitable implementation conditions of the friction welding operation with respect to the connection plate 54 of the 1st pipe 12 and the 2nd pipe 14 are also the same as that of said 1st embodiment.

  As described above, even in the instrument panel beam 52, the first pipe 12 disposed on the driver's seat side portion inside the instrument panel and to which the steering column is attached is made of a large-diameter steel pipe, while the passenger seat side portion. The 2nd pipe 14 arrange | positioned by is comprised with the small diameter aluminum pipe. The first pipe 12 and the second pipe 14 are friction-welded to both surfaces of the steel connecting plate 54. Therefore, also in the present embodiment, the same actions and effects as those obtained in the first embodiment can be enjoyed effectively.

  And in the instrument panel beam 52 of this embodiment, the 1st pipe 12 and the 2nd pipe 14 are especially connected in the state located non-coaxially or eccentrically. Therefore, by appropriately changing the positions of the first pipe 12 and the second pipe 14, the inner space of the instrument panel in which the instrument panel beam 52 is installed can be used more freely and efficiently. It becomes.

  In the instrument panel beam 52 of the present embodiment, when the first pipe 12 and the second pipe 14 are friction welded, the opposite side of the connecting plate 54 to the first pipe 12 and the second pipe 14 are in contact. On the opposite side, the backing portion 60 of the upper clamp member 56 and the backing portion 60 of the lower clamp member 58 are in contact with each other, and the friction welding operation proceeds in a backed up state. Yes. Therefore, it is possible to effectively prevent the connecting plate 54 from being deformed by the opposite pressure applied to the connecting plate 54 from the first pipe 12 and the second pipe 14. Thereby, stabilization of the quality of the instrument panel beam 52 can be realized more effectively.

  Further, in the present embodiment, the upper and lower clamp members 56 and 58 each having the backing portion 60 also have a function as a surrounding member. As a result, both the cost reduction of the manufacturing apparatus for the instrument panel beam 52 and the simplification of the manufacturing work can be advantageously achieved.

  The specific configuration of the present invention has been described in detail based on the representative embodiments. However, this is merely an example, and the present invention is not limited by the above description. It is not a thing.

  For example, the size and shape of the connecting plates 16 and 54 are not limited in any way, depending on the outer diameter of the first pipe 12 and the second pipe 14 to be joined, their arrangement positions, etc. It can be set to a shape.

  Moreover, it is also possible to provide a protrusion at a contact portion of the connecting plates 16 and 54 with the first pipe 12 and the second pipe 14. Specifically, a protrusion having an outer diameter that is substantially the same as or slightly smaller than the inner diameter of each pipe 12, 14 is provided at a position coaxial with the arrangement position of each pipe 12, 14. is there. Such a protruding portion can be a guide for guiding the first pipe 12 and the second pipe 14 to a position where they should be brought into contact with each other, and can effectively form the burr 18 to effectively increase the thickness. The part can be formed.

  Furthermore, an annular groove portion can be provided at the contact portion between the first pipe 12 and the second pipe 14 of the connecting plates 16 and 54. Specifically, an annular shape having a groove width that is substantially the same as or slightly larger than the thickness of the pipes 12 and 14 at a position coaxial with the arrangement position of the pipes 12 and 14. Thus, when the friction welding operation of the first pipe 12 and the second pipe 14 is performed, both side surfaces of the annular groove portion are the outer circumferences of the first pipe 12 and the second pipe 14, respectively. The surface and the inner peripheral surface are contacted and joined. As a result, the joining area is expanded, and the joining strength between the first and second pipes 12 and 14 and the connecting plates 16 and 54 can be advantageously increased.

  Furthermore, the specific structures of the upper clamp members 20 and 56 and the lower clamp members 22 and 58 are not particularly limited to those shown in the first and second embodiments. For example, the upper clamp members 20 and 56 and the lower clamp members 22 and 58 in the first and second embodiments are arranged upside down, and the upper clamp members 20 and 56 are used as the lower clamp members. The lower clamp members 22 and 58 can also be used as upper clamp members.

  Further, the shape of the surrounding surface 46 is not particularly limited to that shown in the first and second embodiments. For example, the tapered surface of the surrounding surface 46 may be a curved surface that is expanded toward the axial center direction of the insertion hole 45. As a result, the burr 18 can be more smoothly joined to the connecting plates 16 and 54 and the second pipe 14.

  Furthermore, a guide surface for guiding the first pipe 12 may be provided in the upper clamp members 20 and 56 and the lower clamp members 22 and 58. The guide surface is provided at the end of the upper clamp members 20 and 56 and the lower clamp members 22 and 58 on the side opposite to the side where the contact portions 30 and 30 are formed. The guide surface is a taper that gradually increases in diameter toward, for example, the opening side of the upper clamp member 20, 56 and the lower clamp member 22, 58 that is opposite to the surface in contact with the connection plates 16, 54. The surface shape is set so that each minimum diameter is the same as or slightly larger than the outer diameter of the first pipe 12.

  In addition, in the some embodiments, when the first pipe 12 and the second pipe 14 are friction-welded to the connecting plates 16 and 54, the first pipe 12 and the second pipe 14 are rotated in the same direction. However, there is no problem even if the first pipe 12 and the second pipe 14 are rotated in opposite directions.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10,52 Instrument panel beam 12 1st pipe 14 2nd pipe 16,54 Connecting plate 18 Burr 20, 56 Upper clamp member 22,58 Lower clamp member 24 Clamp part 26 Connecting rod 28 Substrate part 30 Contact part 32 Concave part 34 Clamp Surface 40 Groove portion 42 Divided surrounding surface 44 Divided guide surface 45 Insertion hole 46 Surrounding surface 48 Guide surface 50 Closed space 60 Backing portion 62 Backing surface

Claims (9)

It is an instrument panel beam that is arranged inside the instrument panel of an automobile so as to extend in the vehicle width direction across the driver's seat side and the passenger's seat side, and is installed between vehicle body members located on both sides in the vehicle width direction. And
The portion arranged on the passenger seat side is made of an aluminum pipe, while the portion arranged on the driver seat side is made of a steel pipe, and the aluminum pipe is friction-welded to one surface of the steel connecting plate. And the aluminum pipe and the steel pipe are integrally connected via the connecting plate by friction welding the steel pipe to the other surface of the connecting plate. .   The instrument panel beam according to claim 1, wherein the steel pipe has a larger diameter than the aluminum pipe.   The instrument panel beam according to claim 1 or 2, wherein the aluminum pipe and the steel pipe are integrally connected via the connecting plate in a state where they are located non-coaxially with each other.   A thick part that enlarges the outer diameter of the contact side end of the burr generated at the contact end of the aluminum pipe with the connection plate due to friction welding of the aluminum pipe to one surface of the connection plate The instrument panel beam according to any one of claims 1 to 3, wherein the instrument panel beam is joined to one surface of the connecting plate. Manufactures an instrument panel beam that is placed inside the instrument panel of an automobile so as to extend in the vehicle width direction across the driver's seat and passenger's side, and is installed between body members located on both sides in the vehicle width direction A way to
Preparing an aluminum pipe and a steel pipe, and an outer diameter of the aluminum pipe and a steel connecting plate having a plate surface larger than the outer diameter of the steel pipe;
Friction welding operation of the aluminum pipe to one surface of the connecting plate and friction welding operation of the steel pipe to the other surface of the connecting plate are simultaneously performed to connect the aluminum pipe and the steel pipe to each other. A step of integrally connecting through a plate;
An instrument panel beam manufacturing method comprising:   While holding the connecting plate having a plate surface larger than the outer diameter of the steel pipe indisplaceable and non-rotatable, and placing the first backing member in contact with one surface of the connecting plate, By placing the second backing member in contact with the other surface of the connecting plate, the connection when the pressing force in the thickness direction is simultaneously applied to different positions on both surfaces of the connecting plate. In a state where the deformation of the plate is prevented, the aluminum pipe is friction-welded to one surface of the connecting plate, while the steel pipe is connected to the other surface of the connecting plate. 6. The method of manufacturing an instrument panel beam according to claim 5, wherein friction welding is performed at a position that is non-coaxial.   When the friction welding operation of the aluminum pipe with respect to one surface of the connecting plate is performed, the surrounding member is provided with an surrounding surface that is positioned away from the outer peripheral surface of the end portion on the contact side of the aluminum pipe with the connecting plate. Surrounding the corresponding contact end of the aluminum pipe, and forming a closed space between the outer peripheral surface of the corresponding contact end, one surface of the connecting plate, and the surrounding surface of the surrounding member. The burr generated at the corresponding contact end of the aluminum by performing the friction welding operation of the aluminum pipe to the connecting plate is confined in the closed space and brought into contact with one surface of the connecting plate, The method of manufacturing an instrument panel beam according to claim 5 or 6, wherein a burr is joined to one surface of the connecting plate.   The surrounding member is composed of a plurality of clamp members that sandwich the connecting plate, and the plurality of clamp members are each provided with a divided surrounding surface obtained by dividing the surrounding surface into a plurality of clamp members. When the connecting plate is sandwiched, the plurality of divided surrounding surfaces are combined to form the surrounding surface, and the abutting side end of the aluminum pipe with the connecting plate is the surrounding surface. The instrument panel beam manufacturing method according to claim 7, wherein the instrument panel beam is surrounded by In the state where the surrounding surface of the surrounding member surrounds the abutting side end of the aluminum pipe abutting against one surface of the connecting plate, the taper gradually increases in diameter toward the tip of the corresponding side end. The method of manufacturing an instrument panel beam according to claim 7 or 8, wherein the instrument panel beam has a surface shape.

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