Lawn mower

Abstract

The application discloses a mower, comprising a tool head, a driving device, a transmission device, a first blade and a second blade, wherein the tool head comprises a housing and the transmission device is arranged in the housing; the driving device is used for driving the tool head to work; the transmission device comprises an output shaft; the first blade and the second blade rotate around the output shaft; the transmission device comprises a first output wheel and a second output wheel, which are connected with the first blade and the second blade respectively; the transmission device further comprises a gear ring, the first output wheel is arranged inside the gear ring, and the second output wheel is drivingly connected inside the gear ring. The application has the advantages of compact structure, small size, light weight, low grass entanglement, high mowing efficiency and long service life.

Description

Technical Field

[0001] This invention relates to a power tool, specifically a lawnmower. Background Technology

[0002] A lawnmower is a handheld tool used to cut weeds in lawns, gardens, pastures, and other areas. With societal development and increasing emphasis on the ecological environment, lawnmowers can enhance the appearance of lawns and vegetation, leading to their widespread use in landscaping and forestry projects. However, existing lawnmower designs have the following drawbacks: during the mowing process, stones and other debris may be kicked up, posing a safety hazard to the user; the transmission structure of existing lawnmowers creates gaps between the housing and the blades, making it prone to grass entanglement and severely impacting daily use. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a lawnmower with a compact structure that is less prone to grass tangling.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A lawnmower includes: a tool head comprising a housing, blades, and a transmission device disposed within the housing; a drive device for driving the tool head to operate; the transmission device includes an output shaft; the blades rotate around the output shaft and include a first blade and a second blade; the transmission device includes a first output wheel and a second output wheel, respectively connected to the first blade and the second blade; the transmission device further includes a gear ring, the first output wheel being disposed inside the gear ring, and the second output wheel being throttle-connected inside the gear ring.

[0006] In some embodiments, the transmission device includes a first planetary gear that is drivenly connected to the output shaft, the first planetary gear meshing with the second output gear and the ring gear, respectively.

[0007] In some embodiments, the transmission device includes a sun gear connected to the output shaft, the sun gear being drive-connected to the first planetary gears.

[0008] In some embodiments, a second planetary gear is provided between the sun gear and the first planetary gear, the first planetary gear and the second planetary gear are driven to the planetary carrier, and the rotation centers of the first planetary gear and the second planetary gear are located on different circumferences of the planetary carrier.

[0009] In some implementations, the planetary support has relative motion with the output shaft.

[0010] In some embodiments, the inner side of the gear ring includes a gear portion and a connecting portion, the gear portion meshing with the first planetary gear, and the connecting portion being fixedly connected to the first output gear.

[0011] In some implementations, the gear ring and the first output wheel are an integral structure.

[0012] In some embodiments, the housing includes an upper housing and a lower housing, the upper housing being disposed above the blade and the lower housing being disposed below the blade, and a flange being provided between the upper housing or the lower housing and the blade; the diameter of the flange is greater than or equal to the diameter of the adjacent housing.

[0013] In some embodiments, the transmission device is provided with a driven shaft, which is coaxially arranged with the output shaft and includes a first end and a second end. The inner side of the first end has relative movement with respect to the outer side of the output shaft, and the outer side is connected to the inner side of the second output wheel. The second end is connected to the second blade.

[0014] In some embodiments, the first output wheel or the second output wheel is provided with a downwardly extending driven portion, which is coaxially arranged with the output shaft and includes a first end and a second end. The inner side of the first end has relative movement with respect to the outer side of the output shaft, and the second end is connected to the blade.

[0015] In some implementations, the rotational speed ratio between the first blade and the second blade is greater than or equal to 0.5 and less than or equal to 2.

[0016] In some embodiments, the distance between the inner ring of the first or second blade and the output shaft is less than or equal to 20% of the housing diameter.

[0017] In some embodiments, the first or second blade has a connecting hole at its center, the connecting hole being polygonal, and the first or second output wheel has a connecting structure corresponding to the shape of the connecting hole.

[0018] The advantages of this invention are: it has a compact structure, small size, and light weight; it is not easily entangled in grass, has high mowing efficiency, and a long service life. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is a sectional view of the vertical section of the present invention;

[0021] Figure 3 This is an exploded view of the structure of the present invention;

[0022] Figure 4 This is a first-view structural schematic diagram of the transmission device and output wheel of the present invention;

[0023] Figure 5 This is a second-view structural schematic diagram of the transmission device and output wheel of the present invention;

[0024] Figure 6 This is a schematic diagram of the structure of the gear ring and the first output wheel of the present invention;

[0025] Figure 7 This is a top view of the transmission device of the present invention. Detailed Implementation

[0026] To facilitate understanding by those skilled in the art, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] A lawnmower is a handheld gardening tool specifically designed for trimming shrubs, lawns, and other vegetation. This embodiment of the lawnmower includes a tool head 10 and a drive unit. The tool head 10 performs the work, and the drive unit drives the tool head 10. The tool head 10 and the drive unit are connected via a transmission rod assembly. One end of the transmission rod assembly is connected to the tool head, and the other end is the handheld part and the drive unit.

[0028] like Figure 1 As shown, the tool head 10 includes a housing 20, a blade 30, and a transmission device 40 disposed within the housing 20. The transmission device 40 transmits the driving force output by the drive device, and the blade 30 rotates around the output axis 401 under the action of the driving force.

[0029] like Figure 2 As shown, the transmission device 40 includes an output shaft 41, which is aligned with the output axis 401. The transmission device 40 is connected to the transmission rod assembly 70 via a first transmission gear 45. The transmission rod assembly 70 includes a transmission rod 72 and a second transmission gear 71 located near the end of the transmission rod close to the tool head 10. The first transmission gear 45 and the second transmission gear 71 are externally meshed. The first transmission gear 45 is sleeved on the upper end of the output shaft 41 or near the upper end. The second transmission gear 71 is sleeved on the end of the transmission rod 72 or integrally formed with the transmission rod 72. Specifically, the transmission axis 401 is generally perpendicular to the working plane of the tool head 10, which is the cutting plane on which the blade 30 rotates. However, for user convenience, the transmission rod 72 is inclined relative to the output axis 401. In this case, both the first transmission gear 45 and the second transmission gear 71 are bevel gears. In other embodiments, when the transmission rod 72 is parallel or perpendicular to the output axis 401, the transmission gears can have other structures, which are not limited here. Compared to existing technologies, the transmission rod in this embodiment is directly connected to the output shaft, which reduces the width of the housing in the horizontal direction.

[0030] The transmission rod assembly 70 is disposed within the connecting housing 51. One end of the connecting housing 51 is connected to the housing 20, and the other end is sleeved on the transmission rod 72 (not shown in the figure). The connecting housing 51 protects the transmission rod assembly 70. The upper end of the output shaft 41 abuts against the inner surface of the housing 20. Specifically, the inner surface of the housing 20 has a protruding annular convex wall, and a first bearing 491 is provided between the convex wall and the output shaft 41. Further, a second bearing 73 is provided between the transmission rod 72 and the connecting housing 51. Depending on the contact length between the transmission rod 72 and the connecting housing 51, multiple second bearings 73 may be provided.

[0031] The transmission device 40 includes a first output wheel 42 and a second output wheel 43, which are respectively connected to the first blade 31 and the second blade 32. The transmission device 40 also includes a gear ring 445, in which the first output wheel 42 is disposed, and the second output wheel 43 is drivenly connected to the inside of the gear ring 445. Specifically, the orthographic projection of the first output wheel 42 in a plane perpendicular to the vertical direction is the first projection, and the orthographic projection of the gear ring 445 in a plane perpendicular to the vertical direction is the second projection. In this embodiment, "disposed inside the gear ring 445" should be understood as the outer edge of the first projection being within the second projection, or coinciding with the second projection.

[0032] like Figure 3-4As shown, a planetary gear train 44 is mounted on the output shaft 41. The planetary gear train 44 drives the first output gear 43 and the second output gear 42, which rotate in opposite directions. The planetary gear train 44 includes a planet carrier 441, which is mounted on the output shaft 41. The planet carrier 441 has a first through hole 441a and a second through hole 441b, where the diameter of the circumference of the first through hole 441a is larger than the diameter of the circumference of the second through hole 441b. A first rotating shaft 442 passes through the first through hole 441a, and a second rotating shaft 443 passes through the second through hole 441b. One end of the first rotating shaft 442 is located in the first through hole 441a, and the other end is connected to the first planetary gear 444. One end of the second rotating shaft 443 is located in the second through hole 441b, and the other end is connected to the second planetary gear 447. Specifically, the first planetary gear 444 and the second planetary gear 447 mesh with each other, and the first planetary gear 444 is located outside the second planetary gear 447. A sun gear 446 is mounted on the output shaft 41, and the sun gear 446 meshes with a second planet gear 447. The sun gear 446 transmits the rotation of the output shaft 41 to the first planet gear 444 through the second planet gear 447. Further, a planet carrier 441 is located at the top of the planetary gear train 44, and the sun gear and planet gears are located below the planet carrier 441. Specifically, there are three first planet gears 444 and three second planet gears 447, and correspondingly three first shafts 442, three second shafts 443, three first through holes 441a, and three second through holes 441b. The planet carrier 441 has a "Y"-shaped structure with three branches, and the included angle between adjacent branches is equal. Other numbers may be used in other embodiments, which are not limited here.

[0033] The second output wheel 42 is located inside the first planetary gear 444, and its outer side meshes with the inner side of the first planetary gear 444. The outer diameter of the second output wheel 42 is greater than or equal to the sum of the radius of the sun gear 446 and the diameter of the second planetary gear 447, meaning that the outer circumference of the second output wheel 42 and the outer circumference of the second planetary gear 447 are on the same circumference. Specifically, the second planetary gear 447 and the second output wheel 42 are meshed together inside the first planetary gear 444. The inner side of the second output wheel 42 is connected to the driven shaft 46, and the upper end of the driven shaft 46 is connected to the lower end of the output shaft 41.

[0034] The planetary gear train 44 also includes a ring gear 445, which meshes internally with the first planet gear 444, meaning the external teeth of the first planet gear 444 mesh with the internal teeth of the ring gear 445. Simultaneously, the ring gear 445 is connected to the first output gear 43. For example... Figure 6 As shown, the inner ring of the gear ring 445 includes a gear portion 445a and a connecting portion 445b, with the gear portion 445a positioned above the connecting portion 445b. The gear portion 445a has a plurality of teeth and meshes with the first planetary gear 444. The connecting portion 445b has no teeth on its surface and is fixedly connected to the outer ring of the first output wheel 43, which rotates under the drive of the gear ring 445.

[0035] In this embodiment, the driven shaft 46 has a sleeve-type structure. The outer side of the upper end of the driven shaft 46 is connected to the second output wheel 42, and the inner side is connected to the output shaft 41. The outer side of the lower end of the driven shaft 46 is connected to the second blade 32, and the inner side is provided with a connector.

[0036] In other embodiments, the second output wheel 42 and the driven shaft 46 can be configured as an integral structure. In this case, the diameter D2 of the driven shaft 46 where it connects to the second blade 32 should be smaller than the diameter D1 of the driven shaft sleeved on the first output wheel 43, so as to ensure that the installation of the third bearing 492 is not restricted.

[0037] The first output wheel 43 includes a disc portion 431 and a centrally located groove portion 432. The disc portion 431 is a horizontally arranged annular disc, and the groove portion 432 is located below the disc portion 431. The groove portion 432 is a downwardly protruding frustum with a through hole at its center. The assembly after the output shaft 41 is connected to the driven shaft 46 passes through the through holes of the disc portion 431 and the groove portion 432 of the first output wheel 43 from top to bottom. A third bearing 492 is also provided between the outer side of the driven shaft 46 and the first output wheel 43. The lower outer side of the groove portion 432 is connected to the first blade 31, transmitting rotation to the first blade 31.

[0038] In other embodiments, the gear ring 445 may be omitted, and the first output wheel 43 performs the function of the gear ring. That is, the outer periphery of the wheel disk portion 431 of the first output wheel 43 protrudes upward to form an internal gear ring, and the first planetary gear 444 meshes with the aforementioned internal gear ring. Compared with the previous embodiment, this embodiment can reduce the diameter of the housing and reduce the overall size of the tool head.

[0039] The housing 20 of the tool head 10 includes an upper housing and a lower housing 23 located above and below the blade, respectively. Specifically, the upper housing includes a first housing 21 and a second housing 22. A connecting housing 51 is connected to the first housing 21. The transmission rod assembly 70, the first transmission gear 45, and the planetary support 441 are all housed within the first housing 21. Specifically, the housing adapts to the internal shape of the transmission device; therefore, the first housing 21 is a frustum-shaped structure with two stepped layers, including a first frustum with a smaller diameter and a second frustum with a larger diameter. The first transmission gear 45 is housed in the first frustum, and the planetary support 441 is housed in the second frustum. Further, the planetary support 441 is fixedly connected to the first housing 21 via a first rotating shaft 442. The upper end of the first rotating shaft 442 protrudes from a first through hole 441a, and the protruding part is embedded in the first housing, locking the planetary support 441. Specifically, the first housing 21 has a groove 210 for accommodating the upper end of the first rotating shaft. The second housing 22 is detachably connected to the first housing 21, and other components of the transmission device are housed within the second housing 22. A fourth bearing 493 is provided between the outer side of the protrusion 431 and the second housing 22. The upper side of the fourth bearing 493 abuts against the lower surface of the wheel disc 431, and the lower side of the fourth bearing 493 rests against the second housing. In other embodiments, the planetary support 441 can be fixed in other ways, or the planetary support 441 may not be provided, as long as the first rotating shaft 442 and the second rotating shaft are fixed; this is not limited here.

[0040] The first output wheel 43 has a first connecting platform 433 at the end of its groove 432, which connects to the first connecting hole 311 at the center of the first blade 31. Similarly, the driven shaft 46 has a second connecting platform 433, which connects to the second connecting hole 311 at the center of the second blade 31. Since the first and second connecting holes are polygonal, the first and second connecting platforms have corresponding shapes. Furthermore, a chamfer 312 is provided at the intersection of adjacent sides of the polygonal connecting hole. The chamfer 312 creates a gap between the corner of the connecting hole and the connecting platform, which makes the blade engagement more stable and facilitates disassembly.

[0041] The distance between the inner ring of the first blade 31 or the second blade 32 and the output shaft 41 or the driven shaft 46 is less than or equal to 20% of the housing diameter. Specifically, the diameter of the inner ring of the first blade 31 is denoted as D3, that is, the diameter of the first connecting hole is D3, and the diameter of the second connecting hole is D2. In this embodiment, since the driven shaft 46 is installed in the first output wheel 43, D3 is greater than D2. In other embodiments, D3 and D2 can also have other relationships, which are not limited here. Further, in this embodiment, both D2 and D3 are less than or equal to 15% of the housing diameter, that is, the distance between the inner ring of the blade and the output shaft 41 or the driven shaft 46 is less than or equal to 5% of the housing diameter. When the diameter of the connecting hole can be close enough to the output shaft or the driven shaft, the stability of the blade during rotation after connection is stronger, and the housing or flange can fit the blade more tightly.

[0042] An upper flange 60 is provided between the upper housing and the blade 30, and a lower flange 61 is also provided between the lower housing 23 and the blade 30. The flange is a solid annular disc or an annular shell, used to fill the gap between the housing and the blade. The diameter of the flange is greater than or equal to the diameter of the adjacent housing, making it flush with the housing, or extending beyond the edge of the housing and covering it. In other embodiments, when the internal structure of the tool head 10 is appropriately sized so that there is no gap between the walls in contact with the housing and the blade, i.e., the outer contour of the internal structure is a regular shape, so that the housing has a relatively flat surface after being tightly attached to the internal structure, the flange may not be provided, and the lower surface of the upper housing and the upper surface of the lower housing can still be tightly attached to the blade. Based on the above structure, the tool head is more compact, which can effectively prevent the cut grass from getting tangled in the gap between the housing and the blade. The flange also helps to prevent wear between the blade and the housing, extending the service life of the machine.

[0043] The lower housing 23 has a W-shaped vertical cross-section with a centrally recessed groove facing upwards. The groove has a through-hole and a sealing connection assembly is located within it. The sealing connection assembly includes a connecting bolt 47 and a fixing member 48. The connecting bolt 47 has a T-shaped cross-section; the head of the T-shape is engaged below the through-hole in the groove, and the tail of the T-shape passes through the through-hole and is located in the driven shaft 46. The lower end of the driven shaft 46 passes through the blade 30 and extends into the lower housing 23. Specifically, a fifth bearing 494 and a fixing member 48 are located on the upper surface of the groove facing inwards. The fixing member is platform-shaped, including a protrusion and a base. The base connects to the upper surface of the groove, and the fifth bearing 494 is located within the protrusion. In other embodiments, the fifth bearing 494 may be omitted, which can reduce the size of the lower housing in the vertical direction. The fifth bearing 494 can reduce the friction between the driven shaft 46 and the housing, and increase the life of the structure. Similarly, the bearing assemblies 49 can reduce the friction between the rotating components and the non-rotating components, and protect the life of the components. In order to reduce the size of the tool head 10, or to achieve the effect of easy structural installation, all bearing assemblies 49 can be omitted or the number of them can be reduced. There is no limitation here, but the tool's life will be sacrificed accordingly.

[0044] In this embodiment, the two output wheels of the transmission device are coaxially arranged. This structure makes the tool head more compact. The transmission rod can be directly connected to the output shaft to achieve a one-input, two-output effect, greatly reducing the width of the tool head in the horizontal direction. The cross-sectional area in the horizontal direction is reduced by about 40%. Although the height in the vertical direction increases slightly, the overall volume is reduced by about 28%. Furthermore, the cost and weight of this structure are reduced. The compactness of the transmission device allows the housing to be closer to the blade, and even allows most of the area to be close to the blade, preventing grass from getting tangled during use. Secondly, the gear load of the above-mentioned transmission device structure is more balanced, improving service life.

[0045] The invention will be further described below through its working principle:

[0046] The transmission device of this invention is a planetary gear system. The driving gear of this planetary gear system is the sun gear 446, which is connected to the output shaft 41. The remaining planet gears are driven and lock the upper planetary support 441, keeping the planetary support 441 stationary and not rotating with the output shaft 41. The sun gear 446 rotates along the first direction 101. Driven by the sun gear 446, the second planet gear 447 and the first planet gear 444 move along the second direction 102 and the first direction, respectively, driving the first output wheel 43 and the ring gear 445 to move along the first direction 101, thereby causing the first blade 31 to rotate along the first direction 101. Under the action of the first planet gear 444, the second output wheel 42 moves along the second direction 102, thereby causing the second blade 32 to rotate along the second direction 102. The first direction 101 and the second direction 102 are opposite in direction; for example, when the first direction 101 rotates clockwise, the second direction 102 rotates counterclockwise. Under the action of the above transmission device, the first blade 31 and the second blade 32 rotate in opposite directions. The first planetary gear 444 and the second planetary gear 447 act as idler gears, which can extend the wheelbase of the first and second shafts and the output shaft, making the force distribution of the gear train more reasonable.

[0047] The rotational speed ratio of the first blade 31 and the second blade 32 is greater than or equal to 0.5 and less than or equal to 2, preferably greater than or equal to 0.67 and less than or equal to 1.5. The relatively close speed ratio of the two blades can prevent the blades from hitting stones during grass cutting, while also improving cutting efficiency and effective cutting area. It also has good cutting efficiency under harsh working conditions and is less prone to grass entanglement under harsh structures.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A mower comprising: a tool head comprising a housing, a blade and a transmission device arranged in the housing; a driving device for driving the tool head to work; characterized in that, the transmission device comprises an output shaft; the blade rotates around the output shaft and comprises a first blade and a second blade; the transmission device comprises a first output wheel and a second output wheel connected to the first blade and the second blade respectively, a planetary gear train is arranged on the output shaft, the transmission device further comprises a ring gear, the first output wheel is arranged inside the ring gear, the first output wheel is coaxial with the output shaft, the second output wheel is drivingly connected inside the ring gear, the second output wheel is coaxial with the output shaft, the first blade and the second blade rotate in opposite directions.

2. The lawnmower as claimed in claim 1, characterized in that the transmission device comprises a first planetary gear drivingly connected to the output shaft, the first planetary gear is in mesh with the second output wheel and the ring gear respectively.

3. The lawnmower of claim 2, wherein, the transmission device comprises a sun gear connected to the output shaft, the sun gear is drivingly connected to the first planetary gear.

4. The lawnmower of claim 3, wherein, a second planetary gear is arranged between the sun gear and the first planetary gear, the first planetary gear and the second planetary gear are drivingly connected to a planetary support, the rotation centers of the first planetary gear and the second planetary gear are located on different circumferences of the planetary support.

5. The lawnmower as claimed in claim 4, characterized in that the planetary support has relative motion with the output shaft.

6. The mower of claim 2, wherein, the inner side of the ring gear comprises a gear part and a connecting part, the gear part is in mesh with the first planetary gear, and the connecting part is fixedly connected with the first output wheel.

7. The mower of claim 1, wherein, the ring gear and the first output wheel are of an integral structure.

8. The mower of claim 1, wherein, the housing comprises an upper housing and a lower housing, the upper housing is arranged above the blade, the lower housing is arranged below the blade, a flange is arranged between the upper housing or the lower housing and the blade; the diameter of the flange is greater than or equal to the diameter of the adjacent housing.

9. The lawn mower of claim 1, wherein, the second output wheel comprises a driven shaft coaxially arranged with the output shaft, comprising a first end and a second end, the inner side of the first end has relative motion with the outer side of the output shaft, the outer side is connected with the inner side of the second output wheel, and the second end is connected with the second blade.

10. The lawnmower as claimed in claim 1, characterized in that, the first output wheel or the second output wheel is provided with a downwardly extending driven part coaxially arranged with the output shaft, comprising a first end and a second end, the inner side of the first end has relative motion with the outer side of the output shaft, and the second end is connected with the blade.

11. The lawnmower as claimed in claim 1, characterized in that, the rotation speed ratio of the first blade to the second blade is greater than or equal to 0.5 and less than or equal to 2.

12. The lawn mower of claim 1, wherein, the distance between the inner circle of the first blade or the second blade and the output shaft is less than or equal to 20% of the diameter of the housing.

13. The lawn mower of claim 1, wherein, a connecting hole is arranged at the center of the first blade or the second blade, the connecting hole is polygonal, and the first output wheel or the second output wheel is provided with a connecting structure corresponding to the shape of the connecting hole.

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