GB2522313A

GB2522313A - Chassis drive device of a garden working machine

Info

Publication number: GB2522313A
Application number: GB1420511.6A
Authority: GB
Inventors: Matthew Ling
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2013-11-21
Filing date: 2014-11-19
Publication date: 2015-07-22
Anticipated expiration: 2034-11-19
Also published as: DE102013223822A1; CN104641802A; GB2522313B; CN104641802B; DE102013223822B4; GB201420511D0

Abstract

A chassis drive device of a garden working machine having at least one brushless motor unit 14 for driving a chassis unit 16 and having at least one gear unit 18 of single-stage form, which cooperates with the brushless motor unit 14 for driving the chassis unit 16. Preferably the gear unit comprises at least one gear element which is connected in a rotationally fixed manner to an output shaft 22 of the gear unit for driving the chassis unit. Preferably the gear unit also comprises at least one further gear element 24 which is connected in a rotationally fixed manner to a rotor element 26 of the brushless motor unit and this further gear element is formed in one piece with the rotor element. Preferably the gear unit has a gear housing 28 which is contact with the brushless motor unit.

Description

Chassis drive device of a garden working machine

Prior art

From US 2013/0046448 Al there is already known a chassis drive device for garden working machines, in particular for electrically operable garden working machines, which comprises a motor unit for driving a chassis unit of the garden working machine and a gear unit of single-stage form, which cooperates with the motor unit for driving the chassis unit.

Disélosure of the invention The invention starts from a chassis drive device of a garden working machine, in particular of an electrically operable garden working machine, having at least one motor unit for driving a chassis unit of the garden working machine and having at least one gear unit of single-stage forn, which cooperates with the motor unit for driving the chassis unit.

It is proposed that the motor unit. is of brushless form.

The gear unit preferably has a single transmission stage.

The gear unit is preferably formed as a toothed-wheel gear unit. In this case, the gear unit is preferably formed as a spur-wheel gear unit. It is, however, also conceivable for the gear unit to have another configuration considered appropriate by a person skilled in the art, such as, for example, a configuration as a bevel-wheel gear unit, as a The brushless motor unit is preferably formed as an electronically commutated electric motor (EC motor) . In this case, the brushless motor unit is formed in particular as a slow-speed EC motor. The brushless motor unit thus has a maximum efficiency at a low maximum speed, in particular at a maximum speed which is less than 8000 rpm. In addition, the brushless motor unit preferably has a maximum rotor diameter which is greater than 20 rum. By means of the configuration of the chassis drive device according to the invention, advantageously a compact configuration for realising a high driving power can be achieved. In addition, advantageously a particularly space-saving arrangement of the chassis drive device according to the invention on th'e garden working machine can be achie(red.

Advantageously packaging costs and transport expenditures can thus be saved. In addition, advantageously a constructional simple configuration of the chassis drive device can be realised, which has few components and can provide a large torque for driving the garden working machine.

Furthermore, it is proposed that the gear unit comprises at least one gear element which is connected in a rotationally fixed manner to an output shaft of the gear unit for driving the chassis unit. The gear element is preferably formed as a toothed wheel, in particular as a spur-wheel toothed wheel. The output shaft is preferably connected to at least one drive wheel of the chassis unit, in particular for transmitting a driving torque generated by means of the brushless motor unit and/or a driving force generated by means of the brushless motor unit. By means of the configuration according to the invention, a particularly advantageous force flow for driving the garden working machine can be achieved.

It is further proposed that the gear unit comprises at least one further gear element which is connected in a rotationally fixed manner to a rotor element of the brushless motor unit. The further gear element is preferably formed as a toothed wheel, in particular as a spur-wheel toothed wheel. In this case, the further gear element is preferably connected in a rotationally fixed manner to a rotor element of the brushless motor unit formed as a rotor shaft. The further gear element is thus formed in particular as a motor pinion. Preferably the further gear element thus directly meshes with the gear element for driving the chassis unit. Particularly preferably the further gear element is connected in rotationally fixed manner to the rotor element, without a movable and/or shiftable clutch for interrupting a force and/or torque transmission. By means of the configuration according to the invention, a simple configuration of the gear unit can be achieved. Advantageously an uncomplex configuration of the gear unit enabling a compact design of the gear unit can thus be realised.

In addition, it is proposed that the further gear unit is formed in one piece with the rotor element. By "in one piece" there is to be understood in particular at least materially joined, for example by a welding process, an adhesive bonding process, an injection moulding process *and/or another process considered appropriate by a person skilled in the art, and/or advantageously integrally formed, such as, for example, by producing in one casting and/or by producing in a one-or more-component injection moulding method and advantageously from a single blank. By means of the configuration according to the invention, advantageously assembly costs, assembly effort and installation space can he saved.

Furthermore, it is proposed that the gear unit comprises at least one gear housing which has at least one outer side on which the motor unit is at least partly arranged. In this case, the motor unit is preferably fastened to the outer side of the gear housing by means of at least one fastening unit of the chassis drive device. In addItion, at least a part of the rotor element on which the further gear element is arranged extends preferably into the gear housing, in a state of the brushless motor unit arranged on the gear Housing. The gear housing is in partic\ilar provided for rotatably mounting the gear element. By "provided" there is to be understood in particular specially designed and/or specially equipped. By an element and/or a unit being provided for a specific function there is to be understood in particular that the element and/or the unit fulfil/s and/or perform/s this specific function in at least a use and/or operating state. By means of the configuration according to the invention, the gear unit can be kept particularly compact, since an accornmodatin region for accommodating the motor unit can be formed at least very largely independently of the gear housing. In addition, advantageously a high ease of servicing with regard to maintenance effort can be achieved. The motor unit can advantageously be detached separately from the gear housing.

It is further proposed that the gear unit has at least one transmission ratio which is less than 0.5. The transmission ratio is preferably formed as a speed transmission ratio which is less than 0.5. In particular the transmission ratio is less than 0.3, preferably less than 0.2 and particularly preferably less than 0.1. In a particularly preferred configuration of the chassis drive device according to the invention, the transmission ratio is, from a maximum driving speed of the brushless motor unit to a maximum output speed of the gear unit, in particular less than 1:5, preferably less than 1:10 and particularly preferably less than 1:12. The transmission ratio is thus calculated preferably from the ratio of maximum driving speed to maximum output speed. By means of the configuration according to the invention, an advantageous drive for an operator to comfortably work a garden arear in particular a' green area and/or lawn area, can be iealised.

In addition, it is proposed that the brushless motor unit has a maximum speed which is less than 5000 rpm.

Preferably, the brushless motor unit has a maximum speed at maximum efficiency of the brushless motor unit which in particular is less than 4500 rpm, preferably less than 3000 rpm and particularly preferably less than 2500 rpm. A particularly advantageous drive for an operator to comfortably work a garden area, in particular a green area and/or lawn area, can thus be realised.

Furthermore, there is proposed a garden working machine, in particular a lawn mower, having at least one chassis drive device according to the invention. Preferably, the garden working machine is formed as a push lawn mower. In this case, the chassis drive device is provided for assisting the operator with pushing the garden working machine over an area to be worked. Further configurations of the garden working machine considered appropriate by a person skilled in the art are likewise conceivable, such as, for example, a configuration of the garden working machine as a lawn trimmer (brush cutter/string trimmer) , as a leaf blower etc. By means of the configuration according to the invention, advantageously a high operating convenience of the garden working machine can be achieved.

It is further proposed that the garden working machine comprises at least one housing unit on which the motor unit and/or the gear unit are/is movably mounted. Preferably, the motor unit and/or the gear unit are/is pivotably mounted on the housing unit. It is, however, also conceivable for the motor unit and/or the gear unit to be mounted in a translatioHally movable manner on the housing unit. A height adjustment for adapting a cutting height of the garden working machine can thus be realised particularly conveniently.

In addition, it is proposed that the garden working machine has at least the chassis unit, which comprises at least one freewheel unit, which is provided for producing a freewheeling of at least one drive wheel of the chassis unit in at least one state. Particularly advantageously, a cornering with the drive of the chassis unit switched on and/or a reverse movement of the garden working machine can thus be made possible.

The chassis drive device according to the invention and/or the garden working machine according to the invention are/is not intended to be limited here to the above-described application and embodiment. In particular, the chassis drive device according to the invention and/or the garden working machine according to the invention can have, for a fulfilling of a functioning described herein, a number of individual elements, components and units differing from a number mentioned herein.

Drawing Further advantages emerge from the following description of the drawing. An exemplary embodiment of the invention is represented in the drawing. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will consider the features expediently also individually and combine them to form useful further combinations.

In the drawing: Fig. 1 shows a garden working machine according to the invention with at least one chassis drive device according to the invention in a schematic representation, Fig. 2 shows a detail view of the chassis drive device according to the invention in a schematic representation, and Fig. 3 shows an exploded view of the chassis drive device according to the invention in a schematic representation.

Description of the exemplary embodiment

Figure 1 shows a garden working machine 12 which is formed as a lawn mower. The garden working machine 12 is in this case formed as an electrically operable lawn mower which is movable by an operator in front of the operator. The garden working machine 12 is thus formed as a so-called push lawn mower. The garden working machine 12 comprises at least one chassis drive device 10 for driving a chassis unit 16 of the garden working machine 12. The chassis drive device 10 is thus provided to assist an operator with moving the garden working machine 12 over a working area.

The garden working machine 12 further comprises at least one housing unit 32 for accommodating and for supporting at least one electric motor unit 38 of the garden working machine 1. The garden working machine 12 furtHer comprises at least one mowing unit 40, already known to a person skilled in the art, for working a working area, in particular a green area. The mowing unit 40 is provided to mow grass growing on the working area. For this purpose, the mowing unit 40 is drivable by the electric motor unit 38. The mowing unit 40 can in this case be formed to be directly drivable by the electric motor unit 38 or the garden working machine 12 comprises at least one mowing-unit gear unit (not shown specifically here) which cooperates with the electric motor unit 38 and the mowing unit 40, in particular is drivingly connected to the electric motor unit 38 and the mowing unit 40. The mowing-unit gear unit can be arranged in a separate gear housing unit (not shown specifically here) of the garden working machine 12 or in the housing unit 32.

The garden working machine 12 further comprises a cuttings removal unit 42, which comprising a cutting space, in which a mowing tool (not shown specifically here) , already known to a person skilled in the art, of the mowing unit 40 is drivably arranged for cutting grass. The mowing unit 40 is thus arranged in the cutting space of the cuttings removal unit 42. The cutting space is arranged directly adjacent to a grass ejection opening of the cuttings removal unit 42.

The grass ejection opening opens into a detachable grass catching device 44 of the garden working machine 12 for catching and/or collecting removed green cuttings, in particular grass.

Furthermore, the garden working machine 12 comprises at least one energy store connecting unit 46 for releasable connection to at least one energy store unit 48. The energy store unit 48 is in this case formed as an accumulator unit. The energy store connecting unit 46 is arranged on the housing unit 32. In this case, the energy store connecting unit 46 has at least two interface elements (not shown specifically here) which are formed as connecting guide rails and have a configuration already known to a person skilled in the art. In addition, the energy store connecting unit 46 comprises at least two contact elements (not shown specifically here) for electrical connection to mating contact elements (not shown specifically here) of the energy store unit 48. The energy store connecting unit 46 further comprises at least one fixing element (not shown specifically here) which is provided to fasten the energy store unit 48, at least in a state arranged on the energy store connecting unit 46, by means of a form-locking and/or force-locking connection.

In the configuration of the garden working machine 12 shown in Figure 1, the energy store connecting unit 46 is provided to releasably accommodate at least two energy store units 48, 50 in total. For ccnnecting the energy store units 48, 50 to the energy store connecting unit 46, the energy store units 48, 50 can each be pushed onto the interface elements or pushed into the interface elements.

In this case, a connecting direction along which the energy store units 48, 50 can be pushed on or pushed in runs at least substantially transversely to a rotation axis of the electric motor unit 38. In particular, the connecting direction runs at least substantially perpendicularly to the rotation axis of the electric motor unit 38. It is, however, also conceivable for the connecting direction to run along another direction considered appropriate by a person skilled in the art, such as, for example, along a direction running at least substantially parallel to the rotation axis of the electric motor unit 38.

For moving the garden working machine 12 on a working area, in particular a green area, the garden working machine 12 has at least one chassis unit 16. The chassis unit 16 comprises in this case at least two drive wheels 36 (only one of the two drive wheels 36 is shown in Figure 1) which are drivable by means of the chassis drive device 10. It is, however, also conceivable for the drive wheels 36 to be drivable by means of the electric motor unit 38, by means of which the mowing unit 40 is drivable. A driving action of the drive wheels 36 can be switched on and/or off in a manner already known to a person skilled in the art. The chassis unit 16 further comprises at least one non-driven rotation wheel 54, in particular at least two non-driven rotation wheels 54, 56. It is, however, also conceivable for the rotation wheel 54, in particular the rotation wheels 54, 56, to be formed likewise to be drivable by means of the chassis drive device 10.

For driving the chassis unit 16, the chassis drive device of the garden working machine 12 comprises at least one motor unit 14 (Figure 2) . In this case, the motor unit 14 is of brushless form. The brushless motor unit 14 is formed as an EC motor. In this case, the brushless motor unit 14 is formed as a slow-speed EC motor which has a large rotor diameter. The brushless motor unit 14 has a maximum speed which is less than 5000 rpm. Preferably, the brushless motor unit 14 has a maximum speed which is less than 2000 rpm. At the maximum speed, the brushless motor unit 14 has a maximum efficiency.

Furthermore, the chassis drive device 10 comrises, for transmitting driving forces and/or driving torques to the drive wheels 36, at least cne gear unit 18 (Figures 2 and 3) . In this case, the chassis drive device 10 comprises at least one gear unit 18 of single-stage form, which cooperates with the brushless motor unit 14 for driving a chassis unit 16. The gear unit 18 is formed as a single-stage toothed-wheel gear unit. The gear unit 18 thus has a single transmission stage. The gear unit 18 has at least one transmission ratio which is less than 0.5. In this case, the gear unit 18 has non-adjustable transmission ratio which is less than 0.1. In particular the gear unit 18 has a transmission ratio which is less than 1:10.

Particularly preferably, the transmission ratio between a driving speed of the brushless motor unit 14 to an output speed of the gear unit 18 is 1:14.8. For this purpose, the gear unit 18 comprises at least one gear element 20 which is connected in a rotationally fixed manner to an output shaft 22 of the gear unit 18 for driving the chassis unit 16. The gear element 20 is formed as a toothed wheel. In this case, the gear element 20 is formed as a spur-wheel toothed wheel. It is, however, also conceivable for the gear element 2Q to have another configuration considered appropriate by a person skilled in the art, such as, for example, as a worm toothed wheel, as a bevel toothed wheel, etc. The drive wheels 36 are arranged on the output shaft 22. In this case, the drive wheels 36 are drivingly connected to the output shaft 22. A transmission of driving forces and/or driving torques from the output shaft 22 to the drive wheels 36 is thus achieved by means of the driving connection between the output shaft 22 and the drive wheels 36. For rotational driving of the output shaft 22 and tt'ius of the drive wheels 36 by means of the brushless motor unit 14, the gear unit 18 comprises at least one further gear element 24 which is connected in a rotationally fixed manner to a rotor element 26 of the brushless motor unit 14. The further gear element 24 is formed in one piece with the rotor element 26. In this case, the further gear element 24 is formed in one piece with a rotor shaft of the motor unit 14. For transmitting a rotational movement to the output shaft 22 and thus to the drive wheels 36, the further gear element 24 meshes with the gear element 20.

The further gear element 24 forms in this case a motor pinion of the brushless motor unit 14 and/or of the gear unit 18. The further gear unit 24 has a maximum diameter which is multiple times smaller than a maximum diameter of the gear element 20. In this case, the maximum diameter of the gear element 20 is at least two times larger than the maximum diameter of the further gear element 24.

Preferably, the further gear element 24 has in addition a maximum diameter which is smaller than a maximum diameter of the output shaft 22.

Furthermore, the gear unit 18 comprises at least one gear housing 28 which has at least one outer side 30 on which the brushless motor unit 14 is at least partly arranged.

The brushless motor unit 14 is fastened to the gear housing 28 by means of a fastening unit 58 of the chassis drive device 10. The fastening unit 58 is in this case formed as a screwed fastening unit. The brushless motor unit 14 is thus fixed to the gear housing 28 by means of at least one fastening element 60 of the fastening unit 58 formed as a screw. For rotatably mounting the output shaft 22, the gear unit 18 comprises at least one bearing element 64 (Figure 3) . The bearing element 64 is formed as a ball bearing. In this case, the bearing element 64 is arranged in the gear housing 28 of the gear unit 18. In total, the gear unit 18 has two bearing elements 64, 66 arranged in the gear housing 28. It is, however, also conceivable for the gear unit 18 to have a number of bearing elements 64, 66 different from two.

The gear housing 28 is fastened (Figure 2) to a carrier element 62 of the chassis drive device 10. The carrier element 62 is provided for rotationally supporting the output shaft 22. In addition, the carrier element 62 is provided for arranging the brushless motor unit 14 and the gear unit 18 on the housing unit 32. The motor unit 14 and/or the gear unit 18 are/is movably mounted on the housing unit 32 for adjustability of a cutting height of the mowing unit 40. In this case, the motor unit 14 and/or the gear unit 18 are/is pivotably mounted on the housing unit 32. For this purpose, the chassis drive device 10 comprises at least one pivot bearing element 52 which is arrangeable on the housing unit 32. The pivot bearing element 52 is formed as a bearing rod. A longitudinal axis of the pivot bearing element 52 thus forms a pivot axis of the motor unit 14 and/or of the gear unit 18. The pivot axis runs in this case substantially parallel to a rotation axis of the output shaft 22. The pivot bearing element 52 is connected in a rotationally fixed manner to the carrier element 62. In addition, a cutting height adjusting unit (not shown specIfically here) of the garden working machine 12 is arranged between the carrier element 62 and the housing unit 32. With one end the cutting height adjusting unit is connected to the carrier element 62 and with a further end the cutting height adjusting unit is connected to t1he housing unit 32. A cutting height bf the mowing unit is thus adjustable as a result of a pivoting movement of the motor unit 14 and/or of the gear unit 18 about the pivot axis caused by the cutting height adjusting unit.

Furthermore, the chassis drive device 10 comprises at least the chassis unit 16, which comprises at least one freewheel unit 34, which is provided for producing a freewheeling of at least one of the drive wheels 36 of the chassis unit 16 in at least one state. The freewheel unit 34 is provided for enabling a freewheeling of the drive wheels 36 during a reverse movement and/or during a cornering movoment of the garden working machine 12 in a driven state of the drive wheels 36. For this purpose, the freewheel unit 34 comprises at least one freewheel element (not shown specifically here) which is assigned to one of the drive wheels 36. In total, the freewheel unit 34 comprises at least two freewheel elements (not shown specifically here), with respectively one freewheel element being assigned to one of the drive wheels 36, The freewheel elements are in this case formed as freewheel bearings which have a configuration already known to a person skilled in the art.