Device for stabilizing the axis of rotation of a gearbox shaft, reinforcement kit and lawnmower with it

Abstract

Device for stabilizing the axis of rotation of the shaft of a gearbox, which is provided in particular on a lawnmower for the rotary drive of a mower deck connected to the shaft, wherein the gearbox for which the device is intended has a bearing for the shaft and is received in a housing which is closed by means of a cover having through holes for screws for fastening the cover to the housing, such that the shaft is led out of the housing through a through hole for the shaft formed in the cover, wherein the device is an attachment device with a support bearing (16) for the shaft and with a retaining part (1) for the support bearing (16), wherein the retaining part (1) has a through opening for the shaft with a recess (15) in which the support bearing (16) is received, and at least three, in particular exactly four,The support bearing (16) has through holes (8, 9, 10, 11) for screws aligned parallel to the axis of rotation of the support bearing (16), in particular to place the retaining part (1) with its through holes (8, 9, 10, 11) provided for the screws onto the cover in front of the through holes provided for the screws in the cover, thereby guiding the shaft through the support bearing (16) and screwing the retaining part (1) and the cover together with the housing by means of the screws.

Description

[0001] The invention relates to a device for stabilizing the axis of rotation of a gearbox shaft and to a reinforcement kit comprising the device. The invention also relates to a lawnmower according to the preamble of claim 10.

[0002] The gearbox is specifically designed for or arranged on a lawnmower and is responsible for the rotary drive of a mower deck. For this purpose, the mower deck is connected to the shaft. However, the device according to the invention can also be used in other gearboxes to stabilize the axis of rotation of their shaft.

[0003] Gearboxes that can be reinforced with the device have a bearing for the shaft and are housed in a casing which is closed by means of a cover which has through holes for screws to fasten the cover to the casing, in such a way that the shaft is led out of the casing through a through hole for the shaft formed in the cover.

[0004] If the gearbox bearing is of a rather weak design, the bearing can wear out over time, thereby reducing the overall lifespan of the gearbox.

[0005] The invention is therefore based on the objective of further stabilizing the axis of rotation of the shaft of a gearbox that is provided on a lawnmower for the rotary drive of a mower deck, thereby increasing the service life of the gearbox, and of providing a device for stabilizing the axis of rotation and a reinforcement set for the gearbox and a lawnmower.

[0006] The invention solves this problem with a device for stabilizing the axis of rotation of the shaft of a gearbox according to claim 1, with a reinforcement set for a gearbox according to claim 8 and with a lawnmower according to claim 10. Advantageous embodiments of the invention are specified in the dependent claims.

[0007] The device according to the invention for stabilizing the axis of rotation of the shaft of a gearbox is provided, in particular, on a lawnmower for the rotary drive of a mower deck, which is connected to the shaft, especially for torque transmission. The gearbox for which the device is intended has a bearing for the shaft and is received in a housing, which is closed by means of a cover having through holes for screws to fasten the cover to the housing, such that the shaft is led out of the housing through a through hole formed in the cover.According to the invention, the device is an attachment device with a support bearing for the shaft and with a retaining part for the support bearing, wherein the retaining part has a through-opening for the shaft with a recess in which the support bearing is received, and has at least three, in particular exactly four, through-holes for screws aligned parallel to the axis of rotation of the support bearing, in particular to place the retaining part with its through-holes provided for the screws onto the cover in front of the through-holes provided for the screws of the cover, thereby guiding the shaft through the support bearing and being able to screw the retaining part and the cover together with the housing by means of the screws.

[0008] The housing of the gearbox for which the invention is intended has, in particular, holes for the screws for attaching the cover to the housing. These holes are, in particular, threaded holes. The holes are formed directly in a housing part of the housing. Alternatively, nuts with threaded holes are provided that are fixed to the housing.

[0009] The device according to the invention is screwed to the housing in addition to the cover and utilizes the existing mounting points for screwing on the cover. Thanks to the device according to the invention, the shaft can be additionally stabilized outside the gearbox housing.

[0010] The reinforcement set for a gearbox according to the invention allows its axis of rotation to be advantageously stabilized retroactively. The reinforcement set for a gearbox according to the invention comprises the device according to the invention in one possible embodiment of this device.

[0011] In particular, the invention is intended for lawnmowers, and especially ride-on lawnmowers, although both the device according to the invention and the reinforcement set according to the invention are also suitable for other gearboxes and can stabilize the axis of rotation of the shaft of the respective gearbox.

[0012] The mower deck of a lawnmower has at least one cutter bar with blades. Preferably, especially if the lawnmower is a larger ride-on mower or lawn tractor, the mower deck has several rotary-driven cutter bars with blades.

[0013] To solve the aforementioned problem, a lawnmower, in particular a ride-on lawnmower with drive, is provided with a mowing deck and a gearbox for the rotary drive of the mowing deck, wherein the gearbox has a shaft to which the mowing deck is connected, in particular for torque transmission, and a bearing for the shaft, wherein the lawnmower has a housing in which the bearing is received and a cover by means of which the housing is closed, wherein a through-hole is formed in the cover through which the shaft is led out of the housing and wherein the cover has through-holes for screws by means of which the cover is fastened to the housing, according to the invention, a device according to the invention, in an embodiment possible within the scope of the invention, for stabilizing the axis of rotation of the gearbox shaft, is installed on the lawnmower.wherein the device is an attachment device with a support bearing for the shaft and with a retaining part for the support bearing, wherein the retaining part has a through-opening for the shaft with a recess in which the support bearing is received, wherein the retaining part has at least three, in particular exactly four, through-holes for screws aligned parallel to the axis of rotation of the support bearing, wherein the retaining part with its through-holes provided for the screws is placed on the cover in front of the through-holes provided for the screws in the cover, wherein the shaft is guided through the support bearing, and wherein the retaining part and the cover are screwed together with the housing by means of the screws guided through the through-holes of the retaining part and the through-holes of the cover.

[0014] Also disclosed is a suitable method for stabilizing the axis of rotation of the shaft of a gearbox, which is provided in particular on a lawnmower for the rotary drive of a mower deck connected to the shaft, wherein the gearbox has a bearing for the shaft and is received in a housing which is closed by means of a cover which has through holes for screws for fastening the cover to the housing, such that the shaft is led out of the housing through a through hole for the shaft formed in the cover.The procedure involves removing the original screws that secure the cover to the housing, then positioning the device according to an embodiment possible within the scope of the invention on the cover, and subsequently mounting the device and the cover together on the housing using replacement screws that are longer than the original screws. In particular, the retaining part, with its through-holes for the screws, is placed on the cover in front of the through-holes in the cover, with the shaft passing through the support bearing, and then screwing the retaining part and the cover together to the housing using replacement screws that pass through the through-holes in the retaining part and the through-holes in the cover.

[0015] For the additional mounting of the device according to the invention on the gearbox housing, the replacement screws must be longer than the original screws. The reinforcement kit according to the invention preferably includes screws, in particular the aforementioned replacement screws, for fastening the device and the cover to the housing, replacing the original screws intended for fastening the cover to the housing.

[0016] Furthermore, particularly with some lawnmowers, the space between the cover in its original state and the mower deck may not be sufficient for positioning the device according to the invention. In this case, the reinforcement set preferably has a milling head, wherein the diameter of the milling head is either at least as large as the diameter of the support bearing or larger than the diameter of the support bearing. In particular, the diameter of the milling head is less than 1.0 cm, preferably less than 0.8 cm, and most preferably less than 0.6 cm larger than the diameter of the support bearing.

[0017] According to the method, it is advantageously provided that, by means of a milling head whose diameter is either at least as large as the diameter of the support bearing or larger than the diameter of the support bearing, an area of ​​the cover located around the through-hole for the shaft is milled off on its outside and thereby reduced compared to its originally provided thickness there, so that after the device is mounted together with the cover on the housing, at least the support bearing protrudes partially into the milled area.

[0018] Accordingly, in the lawnmower according to the invention, preferably an area of ​​the cover located around the through-hole for the shaft is milled off on its outside and thereby reduced in thickness compared to its originally provided thickness, and at least the support bearing protrudes partially into the milled area.

[0019] In the device according to the invention, it is preferably provided that the holding part has a flat base section with a rear side for an arrangement facing the lid and with a front side for an arrangement facing away from the lid.

[0020] The rear side is arranged perpendicular to the axis of rotation of the support bearing. Preferably, either alternatively or, if the front and rear sides are aligned parallel to each other, the front side is additionally arranged perpendicular to the axis of rotation of the support bearing.

[0021] In advantageous embodiments, the support bearing is arranged completely within the through-opening, particularly in the recess. In alternative embodiments, the support bearing protrudes from the recess and projects beyond the base section on its rear side.

[0022] Advantageously, the retaining element adjacent to the rear of the base section has a projecting extension, particularly cylindrical, in the areas surrounding each through-hole. The respective through-hole extends through the extension and the adjacent area of ​​the base section. The extensions are therefore designed to be attached directly to the cover in the areas around the holes and to hold the base section with the support bearing in a position where the support bearing is arranged at a suitable distance from the cover. In particular, the support bearing is thus positioned directly against the cover or at a distance of preferably less than 1.0 cm, more preferably less than 0.5 cm, and most preferably less than 0.2 cm, from the axially adjacent section of the cover.

[0023] The rear side of the base section advantageously forms a flat surface between the extensions and the through-hole. The front side of the base section advantageously forms a flat surface between the through-holes and the through-hole.

[0024] The recess for the support bearing is preferably formed on the rear side of the base section in the through-opening. This means that the support bearing is surrounded on the front and completely or at least partially laterally by the base section and on the rear by the gearbox cover, and is thus largely protected.

[0025] The diameter of the through-opening is larger in the area of ​​the recess than in a front wall that delimits the recess to the front of the base section. The front of this front wall is part of the front of the base section, and the rear of this front wall is a contact surface perpendicular to the axis of rotation of the support bearing for the support bearing received in the recess. In the front wall, the through-opening only needs to have a slightly larger diameter than the shaft to pass through it.

[0026] The diameter of the through-opening in the front wall is preferably less than 3 mm larger, more preferably less than 2 mm larger, and particularly preferably less than 1 mm larger, than the inner diameter of the support bearing. The inner diameter of the support bearing is essentially identical to the outer diameter of the shaft to be accommodated and supported therein.

[0027] Preferably, the thickness of the base section is greater than 0.5 cm, preferably greater than 0.8 cm, and less than 1.5 cm, preferably less than 1.2 cm. The retaining element is preferably formed in one piece. The retaining element is particularly preferably made of aluminum.

[0028] In particularly preferred embodiments of the device according to the invention, especially for supporting the bearing in a lawnmower, the maximum extension of the holding part perpendicular to the axis of rotation of the support bearing is more than 10 cm, preferably more than 12 cm, more preferably more than 14 cm, and less than 25 cm, preferably less than 22 cm, more preferably less than 19 cm.

[0029] Further embodiments are described in the claims, the accompanying drawings, and the following description of a particularly preferred embodiment of the invention illustrated in the drawings. The drawings show: Fig. 1: the holding part of a device according to the invention for stabilizing the axis of rotation of the shaft of a gearbox according to an embodiment of the invention in perspective view; Fig. 2: the holding part of Fig. 1 in a top view of its front; Fig. 3: A first side view of the holding part from the Fig. 1 and Fig. 2; Fig. 4: a second one, opposite the side view of Fig. 3. Side view of the retaining part, offset by 90° from the Fig. 1 to 3; Fig. 5: the holding part of the Fig. 1 to 4 in a sectional view along the in Fig. 2 drawn stepped section plane EE; and Fig. 6: one that in the Fig. Device according to the invention comprising the retaining part shown in 1 to 4 for stabilizing the axis of rotation of the shaft of a gearbox according to an embodiment of the invention in a top view of its rear side.

[0030] In the Fig. 1 and Fig. Figure 2 shows a retaining element 1 of a device designed as an attachment for stabilizing the axis of rotation of the shaft of a gearbox (not shown). The attachment consists of the retaining element 1 and a support bearing (not shown), which can be a commercially available bearing, in particular a ball bearing. The support bearing is fitted into the retaining element 1 and connected to it radially by a positive fit and axially by at least a frictional fit. After mounting on a cover for a gearbox housing, the support bearing is additionally surrounded axially by areas of the retaining element 1 and the cover, and thus also positively secured in its position.

[0031] The gearbox for which the attachment 1 is primarily intended is the gearbox for driving a mower deck on a ride-on lawnmower. A shaft of the gearbox, for example, essentially horizontal, extends through a through-hole in the aforementioned cover from the gearbox housing, which is closed by the cover, and is connected to a mower deck in a torque-transmitting manner. The shaft is supported in the housing by a bearing, as provided by the manufacturer. Within the mower deck, the torque is further transmitted to several cutter bars with blades, which are thus indirectly driven via the gearbox.

[0032] The mounting device according to the invention provides a support bearing for the shaft in addition to the existing bearing. The support bearing can counteract wear of the existing bearing or stabilize the axis of rotation of the shaft if the existing bearing is already partially worn but otherwise still functional.

[0033] The in the Fig. 1 and Fig. The retaining part 1 shown in Figure 2 is formed in one piece and consists entirely of aluminum. The retaining part 1 comprises a flat base section 2 and a total of four extensions 3, 4, 5, and 6 adjoining the outer corners of the base section 2. Fig. 1. The reverse side 7 of the base section 2 is visible. Extensions 3 to 6 protrude from this reverse side 7. Fig. Figure 2, however, shows a top view of the front face 8 of the base section 2. The extensions 3 to 6 with their contours are therefore shown in Fig. Section 2 is hidden from the base section and, as if hidden, contours are indicated by dashed lines in all drawings. The same reference symbols denote the same parts in all figures.

[0034] The retaining element 1 has four through-holes 9, 10, 11, and 12 that extend through the extensions 3 to 6 and the adjoining areas of the base section 2. The extensions 3 to 6 are cylindrical around the through-holes 9 to 12. Extension 6 has a shorter axial length than extensions 3 to 5 because, in the illustrated embodiment, the surface of the lid protrudes in the area of ​​the hole in the lid in front of which extension 6 is to be mounted, and the retaining element 1 is adapted to the shape of the lid. For different lid shapes, correspondingly adapted retaining elements 1 with different lengths and different positions of the through-holes 9 to 12 can be provided within the scope of the invention.

[0035] In the base section 2, a through-opening 13 is provided in a central area for the passage of a section of the gearbox shaft protruding from the gearbox housing. The through-opening 13 has a front wall 14 ( Fig. 1) a section formed on the front 8 of the base section 2, the diameter of which only slightly exceeds the diameter of the shaft to be guided through it. The front wall 14 simultaneously forms an axial boundary for an adjacent circular recess 15 in the through-opening 13. In the completed device according to the invention, the support bearing is received in the recess 15. The support bearing is either arranged completely within the area of ​​the recess 15 or, alternatively, projects from the rear 7.

[0036] Fig. Figure 3 shows the retaining part 1 in a view from the inside Fig. 2. Left-hand side. In Fig. 4 is the retaining part 1 in a view from the in Fig. 2 shown on the page below.

[0037] Fig. Figure 5 finally shows a section through the retaining part 1 along the in Fig. 2. The stepped line EE is drawn. The section passes through the axial centers of the through holes 6 and 9 and the through opening 13.

[0038] In the Fig. In the embodiment shown in Figures 1 to 4, the diameter of the through-opening 13 is 16 mm in the area of ​​the front wall 14 and 35 mm in the area of ​​the recess 15. The axial length of the recess 15 is 9 mm. Together with the thickness of the front wall 14 of 1 mm, this results in a thickness of the base section 2 of 10 mm. The extensions 3 to 5 project 21 mm from the base section 2, so that the axial length of the through-holes 9 to 11 is each 31 mm. The through-holes 9 to 11 have a diameter of 8.5 mm. The diameter of the through-hole 12 is 6.5 mm. The outer diameter of all extensions 3 to 6 is 16 mm.

[0039] The in the Fig. 2 and Fig. The vertically represented extension of the retaining part 1 from extensions 4 and 5 to extension 6, in a direction perpendicular to an imaginary connecting line between extensions 4 and 5, is approximately 103 mm to 104 mm. The orthogonal extension to this extension and the Fig. 2 and Fig. The horizontally depicted extension of the retaining part 1 from extension 3 to extension 6 is approximately 144 mm to 145 mm. Other dimensions are possible within the scope of the invention.

[0040] Fig. Figure 6 shows a device according to the invention, formed from the retaining part 1 and a support bearing 16, from its rear side. After proper assembly on a gearbox, the device faces the gearbox and bears against the gearbox cover at least with extensions 3 to 6. The support bearing 16 is received in the recess 15 and, in particular, is clamped therein completely.

[0041] Thanks to the invention, the service life of a gearbox, especially on a ride-on lawnmower, can be significantly extended.

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