Vehicle seat and adjustment mechanism for a vehicle seat

Abstract

The invention relates to a vehicle seat (2) having a seat part (4) which has a base part (5) and a seat carrier (13) and which is adjustable from a normal position into an inclined reclining position, wherein, for this purpose, the inclination of the seat carrier (13) in relation to the base part (5) is adjustable with the aid of an adjustment mechanism (16), wherein the adjustment mechanism (16) has an actuator (24) having an actuating rod (26) and a toggle lever (18) having two lever arms (20) connected to each other via a joint (22), and the actuating rod (26) engages in the region of the joint (22) in order to adjust the lever arms (20). By this means, a configuration which is in particular also safe in a crash is realized with little outlay on material.

Description

[0001] Description

[0002] Vehicle seat and adjustment mechanism for a vehicle seat

[0003] The invention relates to a vehicle seat and an adjustment mechanism for a vehicle seat. Specifically, the invention relates to a vehicle seat that can be adjusted from a normal position to an inclined, relaxed or reclining position.

[0004] A vehicle seat is, in particular, a seat for a passenger car. The vehicle seat typically comprises a seat section and a backrest section, which is adjustable relative to the seat section. The seat section generally has a seat support, to which padding is usually attached. When adjusted to the reclining position, in addition to the inclination of the backrest section, the inclination of the seat section is also adjusted. Specifically, the front area of ​​the seat section is raised, thus adjusting the seat section's inclination. The seat section's inclination can typically be adjusted by more than 10°. The normal position corresponds to an upright sitting position.

[0005] For tilt adjustment, the seat part has a base section to which the seat support is attached via a joint mechanism. The seat support's inclination relative to the base section is adjustable. The base section is typically also height-adjustable. The vehicle seat is at least indirectly connected to the vehicle body.

[0006] For tilt adjustment, an adjustment mechanism with an actuator is provided, which is designed, for example, as a spindle drive, and acts on an adjustment mechanism via the spindle. During adjustment, high forces must sometimes be transmitted. Furthermore, the adjustment mechanism as a whole must also be designed to be crash-proof. Both of these requirements require the adjustment mechanism to be very robust and complex, depending on the design.

[0007] Based on this, the object of the invention is to provide a vehicle seat that can be adjusted between a normal position and a lying position, as well as an adjustment mechanism for such a vehicle seat, whereby high forces can be absorbed with little use of material.

[0008] The object is achieved according to the invention by a vehicle seat with a seat part which has a base part and a seat support which is articulated thereto via a joint mechanism, wherein the seat part extends from a front side towards a backrest-side rear side and is adjustable from a normal position into an inclined reclining position. For this purpose, the inclination of the seat support relative to the base part can be adjusted using an adjustment mechanism. The front side of the seat support is in an upper position in the reclining position and in a lower position in the normal position. The adjustment mechanism comprises an actuator with an adjusting rod and a toggle lever with two lever arms connected to one another via a joint. One lever arm is articulated, in particular at its end, to the seat support and the other lever arm is articulated, in particular at its end, to the base part.The adjusting rod engages in the area of ​​the joint, preferably directly at the joint, to adjust the lever arms and thus the knee lever. The point of application for the force transmission is, for example, a joint axis of the joint. To adjust the position, the knee angle between the two lever arms is changed, thus adjusting the seat support relative to the base. In particular, the front of the seat section is raised, thus adjusting the overall inclination.

[0009] Furthermore, the object is achieved according to the invention by such an adjustment mechanism for a vehicle seat. The advantages and preferred embodiments listed below can also be applied analogously to the adjustment mechanism. The particular advantage of the described adjustment mechanism is that, due to the lever mechanism with the toggle lever, the adjustment forces required are low and, secondly, that loads, for example in the event of a crash, are at least partially absorbed by the lever mechanism and, for example, transmitted to the base part and via this into the body, so that the actuator is at least largely relieved of these loads.

[0010] Due to this relief of the actuator and also the actuating rod, they can be designed with low material expenditure while achieving high crash safety, which also leads to cost savings.

[0011] A further advantage of the toggle lever mechanism is that the required adjustment movement, and thus the adjustment rod for moving the seat section from the normal position to the reclining position, can be short. This also keeps the load on the adjustment rod low, allowing it to be designed with a small diameter, for example.

[0012] When adjusting to the reclining position, the front of the seat section, specifically the seat support, is typically raised. The front of the seat support is thus adjusted from a lower position in the normal position, specifically the lowest end position, to an upper position in the reclining position, specifically the highest end position.

[0013] In a preferred embodiment, the toggle lever with its two lever arms is oriented toward the front, and the actuator is arranged downstream of the toggle lever toward the rear. This achieves a compact arrangement that is favorable in terms of leverage.

[0014] In a preferred embodiment, the adjusting rod is extended in the normal position compared to the lying position. In particular, the adjusting rod is extended to a maximum extension stroke in the lowest end position. Conversely, the adjusting rod is retracted in the lying position compared to the normal position and, in particular, it is retracted to its maximum extent in the uppermost end position. In this case, extended and retracted are understood to mean in particular the distance between the connection point of the adjusting rod with the toggle lever and a support point for the adjusting rod formed on the actuator. In the retracted state, the connection point is therefore arranged with the shortest distance to this support point. This embodiment with the maximum extension stroke in the normal position and the minimum extension stroke in the lying position ensures that the loads on the adjusting rod are kept to a minimum.In particular, this also makes it possible for loads in the lying position - for example in the event of a crash or even under normal load when the acting forces push the seat support downwards and thus towards the normal position - to only be subjected to tensile forces on the adjusting rod, which - in comparison to compressive forces - are easier to absorb and thus enable small rod diameters.

[0015] In a useful further development, the toggle lever can be moved by means of the actuator from a folded position in the normal position to an extended position in the lying position and is moved accordingly during adjustment. This means that a knee angle between the two lever arms is increased, starting from the normal position to the lying position. This design, in which the toggle lever is in the extended position in the lying position, ensures that at least a large part of any load that may occur is absorbed and transmitted via the extended and preferably at least largely aligned lever arms, without the actuator and especially the adjusting rod being subjected to excessive strain.

[0016] In the stretched position, i.e. specifically in the maximum extended position and thus particularly in the end position for the lying position, the two lever arms are preferably aligned to one another at an obtuse knee angle and preferably at a knee angle in the range of 150° to 180°. In this case, the knee angle is understood to be the angle between the two lever arms on the side oriented towards the actuator. Alternatively, an angle greater than 180° can also be set if required. Especially with this design (i.e. angle greater than 180°), but also with smaller angles, in a preferred variant end stops are formed on the lever arms or for the lever arms of the knee lever, which limit and define the end positions. At least one end stop for limiting the end position of at least one lever arm is provided.

[0017] In the folded position, i.e. especially in the lowest end position and thus particularly in the end position for the normal position, the knee angle is preferably in the range between 60° and 90°.

[0018] In a practical design, the adjustment rod exerts (only) a tensile force to adjust the toggle lever from the normal position to the reclining position, specifically from the folded position to the extended position. This minimizes the load on the adjustment rod during adjustment, and the tensile forces can be transmitted with a small rod diameter and thus with minimal material expenditure. At the same time, this also means that in the event of a crash-related load, for example – where the forces act in the opposite direction to that during adjustment to the reclining position – the adjustment rod is also (only) subjected to tensile forces.

[0019] In a preferred embodiment, the joint that connects the two lever arms is centrally located. This means that the two lever arms, from the joint to their respective attachment point on the seat support or base part, have the same or at least approximately the same length. At least approximately the same length is understood to mean a length difference of up to a maximum of 20% or a maximum of 10% relative to the longer lever arm.

[0020] In a preferred embodiment, two spaced-apart toggle levers are provided, wherein the lever arms of the two toggle levers are more preferably connected via at least one cross member. In particular, the cross member connects two upper lever arms of the two toggle levers and is attached, in particular, to their pivot point on the seat support. Additionally or alternatively, a cross member connects two lower lever arms and is attached, in particular, to their pivot point on the base part.

[0021] The actuator is preferably designed as a spindle drive with a spindle as the actuating rod. Such a spindle drive is particularly robust and therefore particularly suitable. Alternatively, the actuator is designed as a pinion drive. In such a drive, a rack is usually driven by a pinion. In this case, the rack is the actuating rod.

[0022] For convenience, only a single actuator is provided, which is preferably attached to the edge of the seat part. Alternatively, the actuator can be located in a central area, thus spaced from one edge and, in particular, centrally between the opposing side panels of the seat part.

[0023] Preferably, two toggle levers are provided, in particular opposite one another and preferably at the edge of the seat part. The actuator preferably engages only one toggle lever. This results in a stable adjustment mechanism with minimal effort.

[0024] An embodiment of the invention is explained in more detail below with reference to the figures. These show:

[0025] FIG 1 shows a partial perspective view of a seat part of a vehicle seat in a normal position from which the seat part can be adjusted into a lying position,

[0026] FIG 2 is an enlarged view of the seat part in the area of ​​a front side on which an adjustment mechanism is formed, wherein the seat part is in the normal position and

[0027] FIG. 3 is a representation similar to FIG. 2, but with the seat part in the reclining position. A vehicle seat 2, only partially shown in the figures, typically has a backrest part (not shown) and a seat part 4, which is shown without upholstery in FIG. 1. This extends from a front side 6 toward a backrest-side rear side 8. The backrest part (not shown here) is attached to the rear side 8 in an inclination-adjustable manner.

[0028] The seat part 4 has a base part 5, which in the exemplary embodiment comprises a lower base part 10 and an upper base part 12, which are connected to one another via a joint mechanism. In the exemplary embodiment, two struts 14 are articulatedly attached to opposite side walls of the lower part 10, each of which is connected to the upper part 12. The struts 14 form an articulated mechanical connection between the upper base part 12 and the lower base part 10, which enables the height of the upper base part 12 to be adjusted relative to the lower base part 10.

[0029] Furthermore, the seat part 4 has a seat support 13, which is often designed in the manner of a tub and can therefore also be referred to as a seat pan. It is arranged above the upper base part 12 and is usually attached thereto. The upholstery (not shown) is also attached to the seat support 13.

[0030] The inclination of the seat part 4 can be adjusted from the normal position shown in FIG 1 into a reclining position. For this purpose, the seat support 13 is raised at the front 6 relative to the base part 5, specifically to the upper base part 12, so that the upper side of the seat part 4 and thus of the seat support 13 is oriented at an angle towards the rear 8. The inclination of the seat support 13 is typically adjusted by more than 10° during the transition from the normal position to the inclined reclining position, i.e. between the two end positions, and is adjusted, for example, within a range of 15°-25°, as can be seen in particular from a comparison of FIG 2 and FIG 3.

[0031] For tilt adjustment, an adjustment mechanism 16 is provided, which has at least one toggle lever 18, which has two lever arms 20, which are articulated to one another via an approximately centrally arranged joint 22. The lower lever arm 20, oriented toward the lower part 10, is articulated at its ends to the base part 5, in particular to the upper base part 12, and the upper lever arm 20, oriented toward the seat support 13, is articulated at its ends to the seat support 13. In the exemplary embodiment, the two upper lever arms 20 engage a common crossbar. The two lower lever arms 20 engage the side bolsters.

[0032] The adjustment mechanism 16 further comprises an electric actuator 24, which is designed as a spindle drive. It has an adjusting rod 26, which in the exemplary embodiment is formed by a spindle. This rod engages the joint 22 to transmit adjustment forces.

[0033] The toggle lever 18 is oriented towards the front side 6 and the actuator 24 is connected to the toggle lever 18 towards the rear side 8.

[0034] The two lever arms 20 of the toggle lever 18 enclose a toggle angle a between them. This is defined as the angle between the two lever arms 20 on the side of the lever arms 20 oriented toward the actuator 24.

[0035] The tilt adjustment will now be explained in more detail with reference to FIGS. 2 and 3. FIG. 2 shows the seat part 4 in the normal position, with the seat support 13 in its lowest position. In the normal position, the toggle lever is angled, and the toggle angle a is preferably formed as an acute angle and lies, for example, in the range between 60° and 90°. Due to this configuration, the adjusting rod 26 is in a maximum extended stroke position.

[0036] To adjust to the reclining position shown in FIG. 3, the knee lever 18 is now extended by means of the actuator 24, so that it is transferred into the extended end position shown in FIG. 2. For this purpose, the adjusting rod 26 is retracted. A tensile force is exerted on the joint 22, whereby the two lever arms 20 are transferred into the extended position. In this position, the knee angle α in the exemplary embodiment is slightly less than 180° and, for example, in the range between 160 and 170°. In the extended position, an obtuse knee angle α is typically present.

[0037] In summary, an adjustment of the inclination of the seat part 2, specifically the seat support 13, relative to the base part 5 is provided using the illustrated toggle lever kinematics. The adjusting rod 26 is fully extended in the normal position, i.e., the lowest inclination position, and the toggle lever 18 is in its retracted position, in which it is angled forward toward the front side 6. To increase the inclination, the adjusting rod 26 is retracted until the toggle lever 18 reaches its extended position in the highest inclination position.

[0038] This particular design described here has several advantages:

[0039] - When adjusting and in the event of a crash, only a tensile force acts on the adjusting rod 26.

[0040] - Since the adjusting rod 26 is retracted to its maximum in the uppermost inclination position, it is only slightly loaded, for example when load or crash forces occur.

[0041] - Since the knee lever 18 is in the extended position in the lying position, at least a large part of the occurring load or crash forces only acts directly on the lever arms 20 and only a very small part on the adjusting rod 26 and this only as a tensile load.

[0042] - Even in the normal position, any load or crash forces that occur only exert a tensile load on the adjusting rod 26.

[0043] - Since the adjusting rod 26 is subjected to tensile stress when adjusting to the lying position, large adjustment angles and thus long adjustment strokes can be implemented without any problem.

[0044] - As a result of the tensile load, a diameter of the adjusting rod 26 can be kept small, in particular significantly smaller compared to a compressive load.

[0045] - Overall, this makes it possible to design the entire adjustment mechanism 16 with a lightweight construction, and the actuator 24 can also be designed for lower loads, requiring only lower electrical power for the electric drive. This keeps the overall size small.

[0046] List of reference symbols

[0047] 2 vehicle seats

[0048] 4 Seat part

[0049] 5 Base part

[0050] 6 Front

[0051] 8 Back

[0052] 10 lower base part

[0053] 12 upper base part

[0054] 13 seat supports

[0055] 14 struts

[0056] 16 Adjustment mechanism

[0057] 18 knee levers

[0058] 20 lever arm

[0059] 22 joint

[0060] 24 Actuator

[0061] 26 Adjusting rod a knee angle

Claims

Claims Vehicle seat (2) with a seat part (4) which has a base part (5) and a seat support (13) and extends from a front side (6) in the direction of a backrest-side rear side (8) and which can be adjusted from a normal position into an inclined reclining position, wherein for this purpose the inclination of the seat support (13) relative to the base part (5) can be adjusted with the aid of an adjusting mechanism (16) and the front side (6) of the seat support (13) is in an upper position in the reclining position, wherein the adjusting mechanism (16) has an actuator (24) with an adjusting rod (26) and a toggle lever (18) with two lever arms (20) connected to one another via a joint (22), wherein one lever arm (20) is connected in an articulated manner to the seat support (13) and the other lever arm (20) is connected in an articulated manner to the base part (5), and wherein the adjusting rod (26) acts in the region of the joint (22) to adjust the lever arms (20).Vehicle seat (2) according to the preceding claim, wherein the toggle lever (18) is oriented towards the front side (6) and the actuator (24) is arranged downstream of the toggle lever (18) in the direction of the rear side (8). Vehicle seat (2) according to one of the preceding claims, wherein in the normal position the actuating rod (26) is extended compared to the reclining position. Vehicle seat (2) according to one of the preceding claims, wherein the toggle lever (18) can be transferred by means of the actuator (24) from a folded position in the normal position to an extended position in the reclining position. Vehicle seat (2) according to claim 4, wherein in the extended position the two lever arms (20) are oriented at a knee angle (α) of 150° to 180° to one another. Vehicle seat (2) according to claim 4 or 5, wherein in the folded position, the two lever arms (20) are oriented at a knee angle (α) in the range of 60° to 90° to one another. Vehicle seat (2) according to one of the preceding claims, wherein at least one end stop and preferably a plurality of end stops are formed on or for the lever arms (20), whereby the end position of at least one of the lever arms (20) is limited, wherein in the extended position, the two lever arms (20) are preferably arranged at a knee angle (α) of greater than 180°. Vehicle seat (2) according to one of the preceding claims, wherein a tensile force is exerted by the adjusting rod (26) to adjust the knee lever (18) from the normal position to the lying position. Vehicle seat (2) according to one of the preceding claims, wherein the joint (22) is arranged centrally on the knee lever (18).Vehicle seat (2) according to one of the preceding claims, wherein the actuator (24) is designed as a spindle drive with a spindle as the adjusting rod (26). Vehicle seat (2) according to one of the preceding claims, wherein the actuator (24) is arranged on the edge of the seat part (4). Adjusting mechanism (16) for a vehicle seat (2) according to one of the preceding claims for adjusting the inclination of a seat part (4), wherein the adjusting mechanism (16) has an actuator (24) with an adjusting rod (26) and a toggle lever (18) with two lever arms (20) connected to one another via a joint (22), which are provided for an articulated attachment to a seat support (13) or to a base part (5) of the seat part (4), and wherein the adjusting rod (26) acts in the region of the joint (22) to adjust the lever arms (20).

Images