Adjustment mechanism with a linear actuator, vehicle and method for operating a vehicle

Abstract

An adjustment mechanism (6), in particular for a vehicle (1), for example a lawnmower, comprises a linear actuator (9) which has a motor (25), a gear arrangement (28) and a displaceable output element (21, 22), as well as a manually operable actuating mechanism (26), wherein there is a coupling element (19, 29) which is displaceable relative to the output element (21, 22), which represents both a component of the linear actuator (9) and a component of the manual actuating mechanism (26) and, in a mechanical mode, permanently rests against a stop (27) of the output element (21, 22), whereas in a manual mode it can be lifted off the stop (27) by means of the actuating mechanism (26).

Description

[0001] The invention relates to an adjustment mechanism comprising a linear actuator, in particular with an electric motor drive. Furthermore, the invention relates to a vehicle having such an adjustment mechanism and a method for operating a vehicle equipped with such an adjustment mechanism.

[0002] US 2020 / 0170186 A1 discloses a self-propelled implement, which may be a robotic lawnmower. A mowing device is height-adjustable relative to a chassis of the implement. The height adjustment of the implement according to US 2020 / 0170186 A1 includes a ball screw drive.

[0003] Another robotic lawnmower described in EP 2 869 691 B1 comprises a motor mount that provides structural support to a cutting motor at an adjustable height relative to the chassis of the robotic lawnmower. A height adjustment assembly provided for this purpose comprises a preloading element, a screw-engaging nut, and a height adjustment screw.

[0004] US 5,123,234 A and CN 1 11 887 001 A each disclose a mowing vehicle comprising a mowing device and a linear actuator. The mowing device is height-adjustable, and can be adjusted indirectly by the actuator.

[0005] US 2012 / 0 222 395 A1 discloses a hand mower comprising a height-adjustable mowing device. An actuator controlled by an operator can continuously adjust the mowing device.

[0006] DE 10 2021 119 937 A1 relates to a linear actuator with a damping system. The device according to DE 10 2021 119 937 A1 comprises a spring-elastic arrangement that strikes two stop surfaces under preload. Relative displacement between two assemblies, which are part of the device according to DE 10 2021 119 937 A1, is said to make it possible to lift the spring-elastic arrangement from one of the stop surfaces.

[0007] The invention is based on the object of providing more advanced options for operating adjustment mechanisms, such as those used in vehicles, compared to the prior art. The goal is to achieve a particularly favorable balance between equipment complexity and the variety of adjustment options.

[0008] This object is achieved according to the invention by an adjustment mechanism having the features of claim 1. The object is also achieved by a vehicle according to claim 9 and by a method for operating a vehicle designed according to claim 10. The embodiments and advantages of the invention explained below in connection with the operating method also apply mutatis mutandis to the adjustment mechanism and the vehicle equipped therewith, in particular in the form of a working device, for example a lawnmower, and vice versa.

[0009] The adjustment mechanism according to the application comprises a linear actuator, which has a motor, in particular in the form of an electric motor, a single- or multi-stage gear arrangement, and a displaceable output element. The adjustment mechanism also includes a manually operable actuating mechanism, wherein a coupling element is displaceable relative to said output element, which represents both a component of the linear actuator and a component of the manual actuating mechanism, and in a mechanical mode is permanently in contact with a stop of the output element. In contrast, in a manual mode, the coupling element can be lifted from the stop of the output element by means of the actuating mechanism.

[0010] Regarding switching between the various operating modes—that is, the mechanical mode, in particular the electromechanical adjustment mode, on the one hand, and the manual adjustment mode, on the other—there is, for example, a control element that must be actuated to switch between the different modes. Likewise, there are embodiments in which a control element intended for the manual mode, for example, a hand lever or a pedal, can be used spontaneously without first switching to the manual adjustment mode.

[0011] The adjustment mechanism comprises, for example, a screw drive, particularly in the form of a ball screw drive. Reference is made in this context to DE 10 2010 034 488 A1 as an example. Generally, either the threaded spindle or the spindle nut of the screw drive can function as the output element, while the other element represents a rotatable drive element. If the screw drive is a planetary roller gear, a planet carrier can also be used as the drive element.

[0012] Optionally, a reduction gear, for example in the form of a belt drive, i.e., a chain or belt drive, is connected upstream of the screw drive. In the case of a coaxial arrangement of a screw drive designed to convert rotation into linear motion and a reduction gear upstream of the screw drive, which is designed as a rotary-rotary gear, the reduction gear is, for example, a planetary gear or a strain wave gear.

[0013] Regardless of the type of gear arrangement, which includes a screw drive and is used in the mechanical mode of the adjustment mechanism, i.e., converts a rotation into a linear adjustment movement, an output element of the screw drive is coupled to an operating element intended for use in manual mode. The mechanism used for the coupling can, for example, comprise a coupling rod and / or a traction mechanism. In all cases, it is sufficient if the linear actuator is designed to transmit a force to the coupling element in exactly one axial direction.

[0014] The vehicle according to the application can, in particular, be designed as a lawnmower according to claim 9. In any case, the vehicle comprises an adjustment mechanism according to claim 1. In particular, there is an electromechanical height adjustment, which additionally has a manual adjustment mode, i.e., one that does not require electrical power. With an actuating element designed as a hand lever or pedal, the height adjustment of the vehicle can be used intuitively at any time.

[0015] In general, the height adjustment, especially in the case of a self-propelled work machine, can affect the entire vehicle body or only a device attached to the chassis of the vehicle.

[0016] In many applications, it is sufficient if the electromechanical height adjustment is designed for adjustment in exactly one direction, especially for raising a component of the vehicle. Depending on the design of the actuator provided for adjustment and the elements interacting with the actuator, the actuator can, for example, be designed exclusively to generate a tensile force or exclusively to generate a compressive force.

[0017] Adjustment in the opposite direction can be achieved, for example, by gravity. The same applies to manual height adjustment. In this case, too, it may be sufficient to have a control element, for example in the form of a pedal or a hand lever, which can be operated for adjustment in a specific direction, especially for raising, while the opposite adjustment movement, especially the lowering of a vehicle component, can be achieved by gravity. Deviating from this, both electromechanical and manual adjustment can provide an active adjustment option in both directions.

[0018] The vehicle registered can, in principle, be either a vehicle on or in which an operator sits or stands, or a driverless vehicle. In the case of a lawnmower, the height adjustment may be intended, in particular, to adjust the height of a mowing deck.

[0019] If the vehicle is a lawnmower, the height setting of the mower deck can be adjusted mechanically, namely via the linear actuator, within a specified adjustment range. If the mower deck is not yet fully raised, the height setting can be manually adjusted as needed within the remaining adjustment range up to the maximum raised position.

[0020] In general, the method for operating a vehicle having a height-adjustable component is characterized in that the height adjustment of the component in question is carried out electromechanically in a first mode and manually in a second mode.

[0021] According to claim 10, the height adjustment of a mower is varied mechanically, namely by the linear actuator, within a predetermined adjustment range with the aid of the adjustment mechanism. If the mower is not raised to its maximum, the height adjustment of the mower is manually adjusted as needed within an adjustment range remaining up to the maximum raised position of the mower.

[0022] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. These show, partly schematically: Fig. 1 a vehicle, namely a lawnmower designed as a ride-on mower, including an adjustment mechanism for varying the height setting of a mowing deck, in a schematic side view, Fig. 2 an electromechanical actuator of the vehicle intended for adjusting the height of the mower according to Fig. 1, Fig. 3 shows a second embodiment of an adjustment mechanism for a vehicle comprising a linear actuator in a first setting, namely with the threaded spindle of the linear actuator fully extended and the coupling element resting against a stop of the threaded spindle, which can also be moved manually, Fig. 4 the adjustment mechanism Fig. 3, whereby the threaded spindle is also fully extended, but the coupling element is lifted from the stop, Fig. 5 the adjustment mechanism Fig. 3 with partially retracted threaded spindle, with the coupling element resting against the stop, Fig. 6 a diagram showing the relationship between mechanical and manual operation of the adjustment mechanism according to the Fig. 3 to 5.

[0023] Unless otherwise stated, the following explanations apply to all embodiments. Corresponding or essentially equivalent parts are identified by the same reference numerals in all figures.

[0024] A vehicle identified overall by reference numeral 1 is a ride-on mower whose chassis is designated 2 and whose wheels are designated 3 and 4. A mower 5 located beneath the chassis 2 can be adjusted either electromechanically or manually by means of a height adjustment mechanism 6, which will be discussed in more detail below.

[0025] Next to a seat 7 mounted on the chassis 2 is a control unit 8, which is linked to an actuator 9, namely a linear actuator, which is provided for the motorized actuation of the height adjustment 6, i.e., the adjustment mechanism. The adjustment of the mower 5 performed by the actuator 9 is referred to as the first adjustment mode.

[0026] In addition to the first adjustment mode, there is a second, manual adjustment mode which does not require electrical power. For this purpose, a pedal 10 is located in front of the seat 7. Instead of the pedal 10, a manually operated lever can also be used. This applies in particular to embodiments not shown in which the vehicle 1 is designed as a self-propelled device without a driver's seat. The pedal 10 is attached to a lever 11, which is referred to as the front lever without restriction of generality. A central pivot point 12 of the lever 10 is located on the chassis 2, and a lower pivot point 13 is located on the mower 5. Furthermore, the lever 11 is articulated in the section between the central pivot point 12 and the pedal 10 to a rod 14, which in the present case is located horizontally above the chassis 2.

[0027] The rear end of the rod 14, in the arrangement according to Fig. 1, the left end, is articulated to a second, rear lever 15. Overall, the rear lever 15 has a basic shape comparable to the front lever 11. In the case of the rear lever 15, a middle pivot point is designated 16 and a lower pivot point 17. At an upper pivot point 18 of the lever 15, an articulated connection to a push rod 19 is established, which in the embodiment according to the Fig. 1 and Fig. 2 is a coupling element of the adjustment mechanism 6.

[0028] The push rod 19 is part of a screw drive, designated overall by 20, in this case a ball screw drive, of the actuator 9. In this case, the ball screw drive 20 is designed as a non-self-locking screw drive, i.e., a screw drive that can also be actuated from the output side. Alternatively, a self-locking design of the screw drive 20 is also possible.

[0029] A threaded spindle of the ball screw 20 is designated 21 in each embodiment. An associated spindle nut 22 is in the case of Fig. 1 and Fig. 2 as the output element of the ball screw 20. In the embodiment according to the Fig. 3 to 5, the threaded spindle 21 represents the output element of the ball screw 20. In both cases, the output element 21, 22 provides a stop 27 for a coupling element 19, 29, which in the case of Fig. 1 and Fig. 2 as a hollow push rod 19 and in the case of Fig. 3 to 5 is present as a sliding sleeve 29. In any case, the pedal 10 can be used to act on the coupling element 19, 29.

[0030] The push rod 19 is according to Fig. 2 is mounted displaceably in a housing part 23 of the actuator 9. In an analogous manner, in the variant according to the Fig. 3 to 5 the sliding sleeve 29 can be moved in a rotationally secured manner.

[0031] The housing part 23 is firmly connected to a housing of a reduction gear 24, which in the present case is designed as a belt drive. The arrangement comprising the reduction gear 24 and the ball screw 20 is collectively referred to as the gear assembly 28. On the input side of the reduction gear 24, it is connected to the shaft of an electric motor 25, which also represents a component of the actuator 9.

[0032] To raise the mower 5, in case of Fig. 1 and Fig. 2 in the electromechanical adjustment mode, the push rod 19 is extended from the housing part 23. This inevitably also adjusts the front lever 11, which is irrelevant in this case. To raise the mower 5 by muscle power, the driver presses the pedal 10, which moves both levers 11, 15 clockwise, relative to the arrangement according to Fig. 1. Optionally, the control unit 8 displays the current setting of the mower 5. Lowering the mower 5, which is accompanied by retraction of the push rod 19 into the housing part 23, can be assisted or caused by gravity.

[0033] The embodiment according to the Fig. 3 to 5 differs from the embodiment according to the Fig. 1 and Fig. 2 in that the coupling element, which here is in the form of the sliding sleeve 29, is loaded by the actuator 9 not with a compressive force, but with a tensile force. The stop 27, against which the coupling element 29 can be supported, is provided by an end piece 30 of the threaded spindle 21. The maximum stroke of the threaded spindle 21 is H max In the setting according to Fig. 3, the mower 5 (not shown here) is lowered to its maximum. While maintaining the setting of the actuator 9, the sliding sleeve 29 can be lifted from the stop 27 by actuating the pedal 10, whereby the mower 5 is raised manually. Fig. 4 outlined setting is the maximum stroke H maxused to just under half its capacity. The coupling element 29 is loaded with a force, while the threaded spindle 21 is not subjected to any pressure or tensile force. As soon as the pedal 10 is released, the mower 5 lowers again until the setting according to Fig. 3 is reached.

[0034] The Fig. The setting of the linear actuator 9 shown in Figure 5 also assumes that the mower 5 was previously completely lowered. The transition between the setting according to Fig. 3 and the setting according to Fig. 5 is possible purely by motor, i.e. with the sliding sleeve 29 permanently in contact with the stop 27. To a small extent, starting from the setting according to Fig. 5, an additional, manual displacement of the sliding sleeve 29 and thus a lifting of the mower 5 is possible until the upper stop of the mower 5 is reached, in this case accompanied by a stop of the sliding sleeve 29 on the left side of the housing of the linear actuator 9.

[0035] The relationship between the manual adjustment and the setting of the threaded spindle 21 is also shown in the diagram Fig.6. Here, the threaded spindle 21 is adjustable along the x-axis. The deflection of the sliding sleeve 29, i.e., the coupling element, which is clearly related to the height adjustment of the mower 5, is designated A. VM denotes the adjustment range, dependent on the setting of the threaded spindle 21, within which a manual lifting of the mower 5 is possible. To dampen the lowering movement of the mower 5 after manual lifting, damping elements (not shown) can be incorporated into the manual actuation mechanism, designated overall by 26. List of reference symbols 1 vehicle 2 chassis 3 wheel 4 wheel 5 Mower 6 Height adjustment, adjustment mechanism 7 seats 8 Control unit 9 Linear actuator 10 Pedal 11 lever, front 12 middle pivot point 13 lower pivot point 14 bars 15 levers, rear 16 middle pivot point 17 lower pivot point 18 upper pivot point 19 Push rod, coupling element 20 ball screw 21 Threaded spindle 22 spindle nut 23 Housing part 24 reduction gears 25 Engine, electric motor 26 Operating mechanism, manual 27 stop 28 Gear arrangement 29 Sliding sleeve, coupling element 30 end piece A deflection H max maximum stroke VM manual adjustment range x Adjustment range of the output element

Claims

[1] Adjustment mechanism (6), comprising a linear actuator (9) which has a motor (25), a gear arrangement (28) and a displaceable output element (21, 22), and a manually operable actuating mechanism (26), wherein there is a coupling element (19, 29) which is displaceable relative to the output element (21, 22), which represents both a component of the linear actuator (9) and a component of the manual actuating mechanism (26) and in a mechanical mode permanently rests against a stop (27) of the output element (21, 22), whereas in a manual mode it can be lifted off the stop (27) by means of the actuating mechanism (26). [2] Adjustment mechanism (6) according to claim 1, characterized by that the linear actuator (9) comprises a screw drive (20). [3] Adjustment mechanism (6) according to claim 2, characterized by that the screw drive (20) is designed as a ball screw drive. [4] Adjustment mechanism (6) according to claim 2 or 3, characterized by a reduction gear (24) in the form of a belt transmission connected upstream of the screw drive (20). [5] Adjustment mechanism (6) according to one of claims 2 to 4, characterized by that the screw drive (20) has a spindle nut (22) as an output element. [6] Adjustment mechanism (6) according to one of claims 2 to 4, characterized by that the screw drive (20) has a threaded spindle (21) as an output element. [7] Adjustment mechanism (6) according to one of claims 1 to 6, characterized by that the linear actuator (9) is designed to transmit a force to the coupling element (19, 29) in exactly one axial direction. [8] Adjustment mechanism (6) according to one of claims 1 to 7, characterized by that a pedal (10) is provided for the manual displacement of the coupling element (19, 29). [9] Vehicle (1), in particular lawnmower, comprising an adjusting mechanism (6) designed according to claim 1. [10] Method for operating a vehicle (1) according to claim 9, wherein the height adjustment of a mower (5) is varied mechanically, namely by the linear actuator (9), within a predetermined adjustment range by means of the adjustment mechanism (6) and, if the mower (5) is not raised to its maximum, a manual change in the height adjustment of the mower (5) is carried out as required within an adjustment range remaining up to the maximum raised position of the mower (5).

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