BE1030836B1 - Casing tube for a steering column for a motor vehicle and steering column for a motor vehicle - Google Patents

Abstract

The present invention relates to a casing tube (3) for a steering column (1) for a motor vehicle, which has a one-piece, primary-molded metal casting that has a receiving space extending in the direction of a longitudinal axis (L) between a front holding section (31) and a rear clamping section (34), which has a casing wall (35) that surrounds the longitudinal axis (L) over the circumference. In order to enable weight optimization with less manufacturing effort, the invention proposes that the casing wall (35) has at least one opening (36) that is open towards the receiving space, wherein the casing wall (35) surrounds the longitudinal axis (L) in the region of the opening (36) over a partial circumferential section, and the opening (36) extends continuously between the holding section (31) and the clamping section (34).

Description

Steering column casing for a motor vehicle and steering column for a motor vehicle

State of the art

The invention relates to a casing tube for a steering column for a motor vehicle, which comprises a one-piece, primary-molded metal casting, which has a receiving space extending in the direction of a longitudinal axis between a front holding section and a rear clamping section, which has a casing wall surrounding the longitudinal axis over the circumference, wherein the casing wall has at least one opening open towards the receiving space, wherein the casing wall surrounds the longitudinal axis in the region of the opening via a

Circumferential section, and the opening extends continuously between the holding section and the clamping section. A steering column for a motor vehicle with such a casing tube is also the subject of the invention.

With a length-adjustable steering column, a manual steering handle, for example a

Steering wheel which is located at the rear end of the vehicle, which can be rotated about its longitudinal axis,

Steering spindle is mounted in the longitudinal direction given by the longitudinal axis relative to the

Driver position can be adjusted. For this purpose, an adjusting unit in which the steering spindle is mounted is telescopically adjustable in the longitudinal direction and can be moved in the receiving space of a casing tube, which is also referred to as a guide box, box swing arm or outer casing. This casing tube is held by a support unit that is connected to the body of the vehicle.

The steering column casing absorbs all forces acting on the steering column during operation and must ensure a high level of rigidity and natural frequency of the steering column in every adjustment state.

The adjusting unit should be adjustable smoothly and with little play and should be able to be securely fixed by clamping in a clamping section.

In order to meet these requirements, it is known in the art to use the jacket pipe as

In this process, formed parts, preferably made of sheet steel, are

Forming operations such as bending, pressing, punching and the like and assembled by joining operations, for example by welding and the like. Such a jacket pipe, which is described for example in EP 3 515 790 B1, can meet the requirements

requirements for high rigidity. Particularly with more complex designs, several forming and joining operations may be necessary, which results in a correspondingly high manufacturing effort.

In order to realize complex shapes, for example in order to be able to provide a holding section for connection to a support unit, a clamping section for fixing the actuating unit, and if necessary other adapted connecting means and interfaces, it is generally known that the jacket pipe has a

Metal casting or is designed as such. Such a casting can be in a

Primary forming processes, for example in die casting or the like, as a one-piece component, which is designed for connection to holding and clamping devices

Holding and clamping sections, the jacket wall extending therebetween, and furthermore a plurality of mechanical connecting means and the like.

This means that manufacturing steps can be saved. The use of pre-formed cast parts, as known from DE 10 2017 219 914 B4, for example, enables a smaller number of manufacturing steps than with sheet metal constructions. In order to achieve the lowest possible weight, however, subsequent machining of the cast part is necessary. This in turn results in increased manufacturing costs.

A jacket pipe of the type mentioned above is known, for example, from US 2019/0032225 A1 or DE 10 2015 000 028 A1. This requires complex machining and is relatively heavy.

In view of the problems explained above, it is an object of the present invention to enable weight optimization with lower manufacturing costs.

Description of the invention

This object is achieved according to the invention by the casing tube with the features of claim 1 and the steering column according to claim 9. Advantageous further developments emerge from the subclaims.

In a steering column casing for a motor vehicle, which comprises a one-piece, primary-molded metal casting, which has a longitudinal axis extending between a front

Holding section and a rear clamping section, which has a casing wall surrounding the longitudinal axis over the circumference, wherein the casing wall has at least one opening open towards the receiving space, wherein the casing wall surrounds the longitudinal axis in the area of the opening over a circumferential part section, and the opening extends continuously between the holding section and the clamping section, it is provided according to the invention that the opening is delimited by a primary molded cast edge and extends over more than 0.4 times the circumference of the

recording room.

The jacket tube according to the invention has a with respect to the longitudinal axis axially forward

Area has the holding section, which is designed to enable the connection of the jacket tube to a support unit. In the rear area arranged axially at the other end, a clamping section is arranged, which is designed to cooperate with a clamping device for fixing an actuating unit accommodated in the receiving space.

The holding section and the clamping section are connected to one another via the jacket wall extending in the longitudinal direction, which accordingly forms an intermediate region. This limits the receiving space, which extends axially through the clamping section forwards to the holding section, radially outwards as seen from the longitudinal axis.

The casing wall is not closed in a tubular manner over the circumference in the axial intermediate area between the holding section and the clamping section, but the casing tube is designed to be open to the outside in the area of an opening. This opening extends axially between the holding and clamping sections, preferably over the entire length between the holding and

Clamping section. Because the receiving space in the area of the opening is open to the outside, only a peripheral part of the casing wall remains, which forms a kind of web or

A groove is formed, which connects the holding and clamping sections.

One advantage is that the opening can be created in the primary forming process, so that efficient production is possible without additional work steps. In addition, the

Material can be saved by breaking through, which enables an advantageous weight reduction of the jacket pipe.

According to the invention, the opening is limited by a molded cast edge.

The opening is limited to the remaining shell wall and to the holding and clamping section by a cast edge which runs around the entire edge of the opening cross-section of the

Opening preferably runs uninterrupted. According to the invention, this casting edge is produced directly in a primary forming process, preferably in a metal die-casting process.

According to the invention, it is essential that the casting edge is not subsequently

machined, in particular not by machining processes such as milling or the like. In other words, the edge of the opening is formed by the raw surface of the metal casting, which can also be referred to as the casting surface, primary mold surface or raw surface. The fact that no additional machining steps are required results in the advantage of efficient production. A further advantage is that the continuous microstructure created in the primary mold process is not interrupted by machining. In this way, a high level of strength is ensured, so that a material-saving, lightweight, yet sufficiently rigid construction is possible.

Furthermore, the invention provides that the opening extends over more than 0.4 times the circumference of the receiving space. Accordingly, the remaining casing wall surrounds the longitudinal axis on the remaining, non-perforated circumference, on 60% or less of the circumference. Compared with a casing pipe closed over the circumference, a material and weight saving of 40% or more can thus be achieved in the area of the receiving space.

It is preferred that the opening extends over more than 0.5 times the length of the jacket tube. The length of the jacket tube corresponds to the total length measured in the longitudinal direction over the outer axial ends. The length of the opening is preferably more than 50% of the length of the jacket tube, measured externally over the holding section and

clamping section. This enables significant material and weight savings.

It is particularly advantageous that the opening extends over more than 0.6 times the length of the casing pipe. It is advantageous that the entire intermediate section of the

The casing wall between the holding and clamping sections is completely open.

This allows material and weight to be saved over the majority of the total length, enabling further optimization.

It is possible for the clamping section to have a clamping device which is designed to reversibly reduce the opening cross-section of the receiving space. The opening cross-section is the open passage cross-section of the receiving space in the longitudinal direction. The

Clamping device, which can also be referred to as fixing device, engages in the clamping section on the casing pipe and can, for example, be designed in the manner of a

Clamping clamps can be designed as clamps. For this purpose, it can have a clamping bolt as an actuatable clamping device in a manner known per se, for example, which cooperates with a lifting mechanism, which can have a thread, wedge disks, tilting pins or the like in a manner known per se. This lifting mechanism can act in the circumferential direction on both sides of a clamping slot made in the longitudinal direction in the casing wall. By actuating the clamping device, the clamping slot can be compressed in the circumferential direction in such a way that its width is reduced, thereby reducing the opening cross-section of the receiving space. In this way, it is possible to releasably clamp an actuating unit axially accommodated in the receiving space in the casing tube. By actuating the clamping device in the opposite direction, the clamping device can be released, whereby the frictional connection is canceled and the actuating unit can be adjusted in the longitudinal direction, i.e. axially with respect to the longitudinal axis, in a telescopic manner relative to the casing tube. This enables a longitudinal adjustment of the

Steering column realized.

In the jacket pipe according to the invention, functional parts of the clamping device can be integrally formed using the casting process, for example protruding support, holding and/or actuating elements with which the clamping bolt or the lifting mechanism can interact.

It is advantageous that the holding section has a holding means which is designed to accommodate a connecting means. The holding means can, for example, have a horizontally arranged bearing bore which runs transversely to the longitudinal axis and into which an axle or a bearing bolt can be inserted as a connecting means. The casing tube can thus be connected, for example, in a vertically pivotable manner to a support unit which in turn can be fixed to a vehicle body. The holding means or means are preferably designed in one piece with the metal casting. In the area of the holding section, the casing tube can be in

closed in the circumferential direction. This can create a high degree of rigidity in the connection.

It can be provided that the casing wall has at least one further opening outside the opening. The casing wall, which is preferably web-shaped or groove-shaped outside the opening, can have an opening which is preferably smaller relative to the opening. Because this opening is located on one of the openings with respect to the

Since the opening is arranged in a circumferential area opposite the longitudinal axis, which is located at the bottom in the installation position, smaller particles potentially penetrating through the opening from above can automatically escape again through gravity. This increases operational safety.

It is possible that the metal casting is made of an aluminum or magnesium alloy. Such light metal alloys enable high rigidity and natural frequency with a relatively high weight and material saving.

Preferably, the metal casting can be designed as a die-cast part. The production in

Metal die casting allows a great deal of freedom in terms of design, so that a large number of functional elements can be made in one piece with the metal

Cast part of the casing pipe can be integrated.

In a steering column for a motor vehicle, comprising an actuating unit in which a steering spindle is mounted so as to be rotatable about a longitudinal axis and which is accommodated in a receiving space of a casing tube in a telescopically adjustable manner, wherein a clamping device interacts with the casing tube, which can be brought into a release position in which the actuating unit is adjustable relative to the casing tube, or into a fixing position in which the actuating unit is detachably fixed to the casing tube, and wherein the casing tube has a holding section in which a connecting means for connection to a support unit is accommodated, it is provided according to the invention that the

Jacket tube is designed according to one of the previously described embodiments or combinations thereof.

In the steering column, the casing tube according to the invention is connected to the support unit via the holding section. The actuating unit is accommodated in the receiving space and protrudes rearward from the axial opening of the receiving space.

The clamping device can be brought into the clamping position, also known as the fixing position, or into the release position, also known as the release position. This can preferably be done by manual or motorized operation of a clamping device, which interacts with a lifting mechanism acting on the casing tube. Because at least individual functional elements of the clamping device can be designed as one piece with the casing tube, efficient production and a light and compact design are possible.

It can be provided that the casing tube is mounted in the holding section so that its height is adjustable relative to the support unit. For this purpose, the holding section can have a horizontal height adjustment axis lying transversely to the longitudinal axis in a manner known per se, about which the casing tube together with the adjusting unit can be pivoted up or down.

It is possible that between the jacket pipe and the actuator and/or between the

A motorized adjustment drive is attached to the casing tube and a support unit. A linear adjustment drive, for example a motor-driven spindle drive, which acts parallel to the longitudinal axis between the casing tube and the adjustment unit, enables longitudinal adjustment of the steering wheel attached to the adjustment unit. An adjustment drive inserted between the casing tube and the support unit enables motorized height adjustment.

The casing pipe can have integrally formed connecting elements for fastening and supporting the adjustment drive(s). This simplifies production and assembly.

Description of the drawings

Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In detail:

Figure 1 shows a steering column according to the invention in a schematic perspective view,

Figure 2 is another view of the steering column according to Figure 1,

Figure 3 is a cross-section through the steering column casing tube according to the invention

Figure 1,

Figure 4 shows the jacket pipe according to Figure 3 in a schematic perspective view,

Figure 5 is another view of the jacket pipe according to Figure 4.

Embodiments of the invention

In the various figures, identical parts are always provided with the same reference symbols and are therefore usually only named or mentioned once.

Figures 1 and 2 show a steering column 1 according to the invention in different perspective views. This has an actuating unit 2 in which a steering spindle 21 can be rotated by a

The longitudinal axis L is rotatably mounted. At the rear, in the figures pointing downwards to the right

end has a fastening section 22 for attaching a steering wheel, not shown here.

The actuating unit 2 is accommodated in a casing tube 3 according to the invention. This has a holding section 31 in its front area axially facing away from the actuating unit 2.

This has a bearing bore 33 that runs transversely to the longitudinal axis L in the direction of a horizontal height adjustment axis 32. In this, the casing tube 3 is pivotably mounted in the height direction H relative to the vehicle body, for example by means of a bearing bolt (not shown here). In the area of the holding section 31, the steering spindle 21 can be rotatably mounted in the casing tube 3.

In the rear area, where the actuator 2 protrudes axially from the casing tube 3, the

The casing pipe 3 has a clamping section 34.

A casing wall 35 extends between the holding section 31 and the clamping section 34. This has an opening 36 at the top, which is indicated by the dashed arrow. In the area of the opening 35, in the example shown, more than 40% of the

The casing wall 35 is omitted. Conversely, the remaining casing wall 35, which extends approximately in the form of a channel in the longitudinal direction, surrounds the steering spindle 21 by less than 60%.

The opening 36 is limited by a circumferential cast edge 37 of the casing wall 35. This is predominantly, preferably completely, primary formed, i.e. preferably produced by die casting without subsequent mechanical processing. In other words, the

Casting edge 37 is formed continuously, or at least predominantly, by a raw, unprocessed casting surface.

The casing tube 3 is held in the region of the clamping section 34 by a console-like support unit 4 which has fastening holes 41 for attachment to the vehicle body (not shown).

A clamping device 5 is attached to the support unit 4, which has a clamping bolt 51 which runs transversely to the longitudinal axis 5 and which can be rotated by means of a clamping lever 52. This allows a lifting mechanism 53 which is operatively arranged between the support unit 4 and the casing tube 3, for example a known wedge disk, cam or tilting pin mechanism, to be actuated and brought into a fixing position or a release position as desired. In the fixing position, the casing tube 3 is clamped between two side cheeks 42 of the support unit 4, so that the casing tube 3 is clamped to the support unit 4, and the casing tube 3 is compressed in the clamping section 34 in order to reduce the cross-section of the receiving space, so that the actuating unit 2 is clamped in the casing tube 3. In the release position, the actuating unit 2 can be adjusted telescopically in the longitudinal direction, as indicated by the double arrow.

The jacket tube 3 according to the invention is shown in different views in Figures 3, 4 and 5. It is designed as a one-piece metal die-cast part, preferably made of an aluminum or magnesium alloy.

In Figure 3, which shows a cross section A-A from Figure 4, it is clearly visible that the sectioned casing wall 35 is approximately channel-shaped, and the longitudinal axis

L on a circumferential section of less than 60% of the circumference.

In Figure 4, the total length M of the jacket pipe 3 is shown, as well as the length D of the

Opening 36, which extends longitudinally continuously between the holding section 31 and the clamping section 34. In the embodiment shown, the length D is greater than 0.6 times the length M, the following applies: D > (0.6 * M).

In Figures 4 and 5 it can be seen that on both sides of a clamping slot 38 protruding

Support elements 39 are formed integrally onto the casing tube 3. The lifting mechanism 53 of the clamping device 5 engages these, with the clamping bolt 51 being guided through openings 391.

In the lower area, on the side opposite the opening 36, an opening 392 is made in the casing wall 35. Any foreign bodies that may penetrate through the opening 36 can then automatically fall out of the receiving space again by gravity.

List of reference symbols 1 Steering column 2 Actuating unit 21 Steering spindle 22 Fastening section 3 Jacket tube 31 Holding section 32 Height adjustment axis 33 Bearing bore 34 Clamping section 35 Jacket wall 36 Opening 37 Cast edge 38 Clamping slot 39 Support element 391 Opening 392 Opening 4 Support unit 41 Fastening holes 42 Side cheeks 5 Clamping device 51 Clamping bolt 52 Clamping lever 53 Lifting mechanism

L Longitudinal axis

H Altitude direction

M Length of the casing pipe 3

D Length of the opening 36

Claims (12)

PATENT CLAIMS 1. A casing tube (3) for a steering column (1) for a motor vehicle, which has a one-piece, molded metal casting that has a receiving space extending in the direction of a longitudinal axis (L) between a front holding section (31) and a rear clamping section (34), which has a casing wall (35) surrounding the longitudinal axis (L) over the circumference, wherein the casing wall (35) has at least one opening (36) open towards the receiving space, wherein the casing wall (35) surrounds the longitudinal axis (L) in the region of the opening (36) over a circumferential partial section, and the opening (36) extends continuously between the holding section (31) and the clamping section (34), characterized in that the opening (36) is delimited by a molded cast edge (37) and extends over more than 0.4 times the circumference of the receiving space. 2. Jacket pipe according to claim 1, characterized in that the opening (36) extends over more than 0.5 times the length (M) of the jacket pipe (3). 3. Jacket pipe according to one of the preceding claims, characterized in that the opening (36) extends over more than 0.6 times the length (M) of the jacket pipe (3). 4. Jacket pipe according to one of the preceding claims, characterized in that the clamping section (31) has a clamping device (5) which is designed for reversibly reducing the opening cross-section of the receiving space. 5. Jacket pipe according to one of the preceding claims, characterized in that the holding section (31) has a holding means (33) which is designed to receive a connecting means. 6. Jacket pipe according to one of the preceding claims, characterized in that the jacket wall (35) has at least one further opening (392) outside the opening (36). 7. Jacket pipe according to one of the preceding claims, characterized in that the metal casting is made of an aluminum or magnesium alloy. 8. Jacket pipe according to one of the preceding claims, characterized in that the metal casting is designed as a die-cast part. 9. Steering column (1) for a motor vehicle, comprising an actuating unit (2) in which a steering spindle (21) is mounted so as to be rotatable about a longitudinal axis (L) and which is accommodated in a receiving space of a casing tube (3) in a telescopically adjustable manner, wherein a clamping device (5) cooperates with the casing tube (3) which can be brought into a release position in which the actuating unit (2) is adjustable relative to the casing tube (3), or into a fixing position in which the actuating unit (2) is detachably fixed to the casing tube (3), and wherein the casing tube (3) has a holding section (31) in which a connecting means for connection to a support unit (4) is accommodated, characterized in that the casing tube (3) is designed according to one of the preceding claims 1 to 8th. 10. Steering column according to claim 9, characterized in that the clamping device (5) has a manually or motor-operated clamping means (52) which cooperates with a lifting mechanism (53) engaging the casing tube (3). 11. Steering column according to one of claims 9 to 10, characterized in that the casing tube (3) is mounted in the holding section (31) so as to be height-adjustable relative to the support unit (4). 12. Steering column according to one of claims 9 to 11, characterized in that a motorized adjustment drive is mounted between the casing tube (3) and the adjusting unit (2) and/or between the casing tube (3) and a support unit (4).