A micro tiller walking transmission shaft structure and a micro tiller

Abstract

The utility model discloses a kind of micro tiller walking transmission shaft structure and micro tiller, wherein, micro tiller walking transmission shaft structure includes driving main shaft, coaxially fixedly arranged with driving wheel tooth for input power on the driving main shaft, and with the accommodating cavity of coaxial through arrangement;The two ends of the accommodating cavity are symmetrically inserted with output shaft;Two the opposite end of the output shaft is connected to form bearing beam by the shaft hole cooperation structure of relatively rotatable;The driving main shaft is relatively rotatably erected on the bearing beam formed by two the output shaft, and any the output shaft and the driving main shaft between are provided with clutch mechanism.The utility model has can be in the narrow space in micro tiller walking box, under the premise of using split type output shaft to meet the steering demand, significantly improve the advantages such as output shaft support rigidity and bending resistance.

Description

Technical Field

[0001] This utility model relates to the field of agricultural machinery technology, and in particular to a micro-tiller's walking drive shaft structure and the micro-tiller itself. Background Technology

[0002] Mini tillers, as lightweight and flexible agricultural machinery, are widely used in narrow terrains such as mountainous areas, hills, and greenhouses. Existing mini tillers typically use a through-type hexagonal shaft as the power output, rigidly connecting the left and right wheels and causing them to rotate synchronously. While this structure is simple, when turning in the field, the operator cannot utilize differential steering and must rely on manual labor to forcibly drag the machine to overcome ground friction, or press down on the handlebars to suspend the drive wheels in the air to complete the turn. This results in extremely high labor intensity and poses safety hazards.

[0003] To reduce the operator's workload during steering, the applicant considered using a clutch mechanism to separate the power to the two wheels, eliminating the traditional continuous long axle and replacing it with two independent output half-shafts on the left and right sides within the travel box for independent control. However, this improvement raised new support strength issues in the specific application scenario of a mini-tiller. Since mini-tillers are mainly used for inter-row operations, the width of their travel box is usually designed to be very narrow to ensure maneuverability. With a split half-shaft structure, each half-shaft can only be inserted into one side of the box, and due to the limited width of the box, the bearing support span of each half-shaft within the box is very short.

[0004] Meanwhile, when a mini tiller is working, the wheels or blades need to withstand enormous ground reaction forces and alternating impact bending moments. This harsh stress condition of "short support span and long cantilever" makes the split output half-shaft extremely prone to lever warping during operation. This causes the bearing to bear severe eccentric loads and fail prematurely, or causes the shaft end oil seal to fail and leak oil due to journal runout. In severe cases, it can even directly cause the half-shaft to break at the root.

[0005] Therefore, how to enhance the support strength of the output half-shaft under the contradictory conditions of having to adopt a split shaft structure to achieve steering, and being limited by the extremely narrow space of the travel box resulting in insufficient insertion depth, has become an urgent problem to be solved. Utility Model Content

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is: how to provide a micro-tiller travel drive shaft structure and micro-tiller that can significantly improve the output shaft support rigidity and bending resistance within the narrow space of the micro-tiller travel box, while using a split output shaft to meet steering requirements.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A drive shaft structure for a micro-tiller includes a drive shaft, on which a drive gear for inputting power is coaxially fixedly disposed and has a coaxially through-hole accommodating cavity; output shafts are symmetrically inserted into both ends of the accommodating cavity; the opposite ends of the two output shafts are connected by a shaft hole mating structure that allows relative rotation to form a bearing beam; the drive shaft is rotatably mounted on the bearing beam formed by the two output shafts, and a clutch mechanism is provided between each output shaft and the drive shaft.

[0009] The aforementioned structure abandons the traditional force-bearing mode of "box supporting the main shaft, and the main shaft cantilever supporting the output shaft" found in micro-tillers, and innovatively constructs a support architecture of "internal beam, suspended main shaft". Through a shaft hole mating structure, the two originally independent split output shafts are internally connected, forming a single load-bearing beam spanning the interior of the travel box. This ensures that the two output shafts are no longer isolated short cantilever structures in terms of force distribution. Simultaneously, the drive main shaft, utilizing its own housing cavity, is directly mounted on this load-bearing beam, in a suspended state, responsible only for transmitting torque and no longer bearing the bending moment load from the wheels. This structure significantly improves the overall rigidity and bending resistance of the split shaft system without increasing the width of the box.

[0010] As an optimization, the shaft-hole mating structure includes an inner support shaft and inner support holes respectively opened at opposite ends of the two output shafts. The inner support holes are coaxially arranged on the output shafts, and the two ends of the inner support shaft are rotatably inserted into the two inner support holes respectively.

[0011] In this way, by using the inner support shaft as an intermediate connector, the two independent output shafts on the left and right are precisely aligned and physically connected at the geometric center, forming the physical basis of the aforementioned load-bearing beam. At the same time, the rotatable fit between the inner support shaft and the inner support hole ensures that the left and right output shafts can rotate independently, providing the necessary conditions for differential steering or single-sided clutch parking.

[0012] Furthermore, a limiting ring is provided between the two output shafts, the limiting ring being protrudingly disposed on the inner wall of the receiving cavity of the drive spindle or in the middle of the inner support shaft.

[0013] In this way, a reliable axial thrust reference is provided between the two output shafts, preventing the two output shafts from moving excessively inward when the wheels are subjected to lateral compressive force, ensuring the stability of the axial clearance of each component inside the transmission shaft system, and preventing interference.

[0014] As an optimization, a support shaft section is formed at the opposite end of each of the two output shafts, the outer diameter of the support shaft section matching the inner diameter of the receiving cavity, and the drive spindle is rotatably supported on the support shaft sections of the two output shafts through the inner wall of the receiving cavity.

[0015] This provides a specific physical interface for the "floating" installation of the drive spindle. By using the support shaft section at the inner end of the output shaft as a sliding bearing surface, high-precision coaxiality between the drive spindle and the output shaft is ensured, and the smooth operation of the floating support is achieved. This not only shares the radial load but also provides a benchmark for the stable operation of the clutch mechanism.

[0016] As an optimization, an annular limiting plate is fixedly provided at the opening end of the receiving cavity. The inner diameter of the limiting plate is smaller than the inner diameter of the receiving cavity. One end of the output shaft that passes through the limiting plate is a small-diameter shaft segment. A shoulder is formed between the small-diameter shaft segment and the main body of the output shaft. The shoulder is located inside the receiving cavity and can rotatably abut against the side of the limiting plate facing the inside of the receiving cavity.

[0017] In this way, without the need to add an extra locking nut or pin, the fit between the limiting plate and the shoulder of the output shaft physically restricts the output shaft from coming out of the receiving cavity, thus achieving axial anti-disengagement limiting of the output shaft; combined with the aforementioned inner limiting retaining ring, the position of the output shaft in the axial direction is completely locked, further improving the overall stability of the structure.

[0018] To solve the above-mentioned technical problems, the present invention adopts the following second technical solution:

[0019] A mini-tiller includes a travel box, in which a mini-tiller travel drive shaft structure as described above is installed. In the mini-tiller travel drive shaft structure, travel bearings are installed at the outer ends of the two output shafts and are rotatably supported on the box wall of the travel box by the travel bearings.

[0020] In this way, the huge ground reaction force and bending moment load transmitted from the wheels are directly transmitted to the traveling box body through the load-bearing beam formed by the output shaft and the traveling bearing at the outer end. The force path is shorter and more reasonable, which significantly improves the durability and reliability of the entire micro-tiller.

[0021] In summary, this utility model has the advantages of significantly improving the output shaft support rigidity and bending resistance within the narrow space of the micro-tiller's travel box, while using a split output shaft to meet steering requirements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the steering clutch transmission system in this embodiment.

[0023] Figure 2 for Figure 1 A frontal view of the structure.

[0024] Figure 3 for Figure 2A cross-sectional structural diagram.

[0025] Figure 4 This is a schematic diagram of the axle sectional view of the steering clutch transmission system.

[0026] Figure 5 This is a partial exploded view of the steering clutch transmission system.

[0027] Figure 6 A schematic diagram of the axial sectional structure for driving the spindle.

[0028] Figure 7 This is a schematic diagram of the shaft side sectional view of the output shaft.

[0029] Figure 8 This is a cross-sectional view of the sliding sleeve. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to an embodiment employing the structure of the present invention.

[0031] In practical implementation: such as Figures 1 to 8 As shown, a mini-tiller includes a travel box, and a steering clutch transmission system is installed inside the travel box.

[0032] The steering clutch transmission system includes a drive shaft 1, on which a drive gear 13 for inputting power is coaxially and fixedly mounted. In this embodiment, the drive gear 13 is preferably a spur gear integrally formed (e.g., precision forged) on the drive shaft 1 to obtain optimal structural strength. In specific implementations, spur gears, helical gears, pulleys, or sprockets, etc., that are separately mounted or integrally formed, can also be used according to transmission requirements.

[0033] like Figures 1-6 As shown, the drive spindle 1 has symmetrically arranged clutch structures at both ends. The clutch structure includes a receiving cavity 11 extending axially and coaxially arranged on the drive spindle 1, and an output shaft 2 rotatably inserted into the receiving cavity 11. The receiving cavity 11 has at least one radially penetrating locking hole 12, and the output shaft 2 has a locking groove 21 corresponding to the locking hole 12 in the circumferential direction. A locking member 3 that can slide radially along the drive spindle 1 is provided in the locking hole 12. An axially movable sliding sleeve 4 is sleeved on the drive spindle 1. The inner wall of the sliding sleeve 4 has a pressing surface and a releasing surface that are axially corresponding to the locking hole 12. The pressing surface and the releasing surface are axially distributed on the sliding sleeve 4, so that the locking member 3 is embedded in the locking groove 21 when the pressing surface moves to the locking hole 12, and can be dislodged from the locking groove 21 when the releasing surface moves to the locking hole 12.

[0034] By employing a locking method that uses a sliding sleeve to drive the radial movement of the locking element, the axial movement of the shaft or gear in traditional dog clutches or spline clutches is replaced. This achieves a "shaft stationary, locking element moving" clutch logic. Throughout the clutch engagement and disengagement process, there is no relative axial displacement between the drive shaft and the output shaft, ensuring that the output shaft remains deeply inserted within the drive shaft's receiving cavity. This guarantees sufficient engagement length between the two shafts even in the disengaged state, thus ensuring the coaxiality and support rigidity of the transmission system. Furthermore, the sliding sleeve only needs to slide outside the drive shaft, without occupying axial space within the shaft system, resulting in a more compact overall structure that can adapt to the narrow installation environment at the bottom of the tiller's travel box. Simultaneously, the axial thrust of the sliding sleeve is converted into radial pressure on the locking element, resulting in a large locking force and stable engagement.

[0035] Multiple locking elements 3 and locking grooves 21 are evenly distributed along the circumference of the corresponding drive shaft 1 and output shaft 2, respectively, and the number of locking grooves 21 is an integer multiple of the number of locking elements 3. Multiple evenly distributed locking elements enable multi-point synchronous force application, avoiding shaft force eccentricity and wear caused by single-point locking. Simultaneously, setting the number of locking grooves to an integer multiple of the number of locking elements allows the output shaft to align with the nearest locking groove and engage with it only by rotating a small angle during rotation, significantly improving the response speed and alignment success rate of the steering clutch.

[0036] like Figure 5 and Figure 7 As shown, in this embodiment, the locking groove 21 is a spline groove extending axially along the output shaft 2, the locking member 3 is a spherical ball, and the locking hole 12 is a circular through hole, the diameter of which is adapted to the diameter of the locking member 3. Specifically, the outer surface of the output shaft 2 is provided with a plurality of spline teeth extending axially, and the locking groove 21 is formed between adjacent spline teeth; a transition ring groove is also provided on the spline teeth, which is circumferentially continuous, and the axial position of the transition ring groove corresponds to the axial position of the locking hole 12; the radial depth of the transition ring groove is less than the tooth height of the spline teeth, so that the spline teeth still retain part of the tooth structure at the bottom of the transition ring groove.

[0037] By creating shallow transition grooves at the tips of the spline teeth, when the clutch is in the transitional state between engagement and disengagement, and there is a speed difference between the output shaft and the drive shaft, the locking element (such as a ball) will not violently impact or rub against the sharp edges of the teeth. Instead, it can first fall into this shallow transition groove. Since the groove depth is less than the tooth height, the spline teeth are not cut off. Therefore, the sidewalls of the teeth still exist at the transition groove (although they are shorter). This not only ensures the overall strength of the spline but also serves as a pre-guide for the locking element to slide into the fully locked spline groove, effectively reducing the jerking sensation and the risk of jamming during clutch engagement / disengagement.

[0038] like Figure 8 As shown, the pressing surface and the releasing surface are a first cylindrical surface 42 and a second cylindrical surface 41 coaxially arranged on the inner wall of the sliding sleeve 4. The inner diameter of the first cylindrical surface 42 matches the diameter of the shaft segment where the locking hole 12 is located, and is smaller than the inner diameter of the second cylindrical surface 41. The difference between the radius of the second cylindrical surface 41 and the radius of the receiving cavity 11 matches the radial dimension of the locking member 3 on the driving spindle 1. A variable diameter section with a gradually changing inner diameter is connected between the first cylindrical surface 42 and the second cylindrical surface 41.

[0039] The first cylindrical surface provides a physical constraint for forced locking, preventing the locking element from coming out under the reaction force of the load; the space difference between the second cylindrical surface and the receiving cavity constitutes a clearance space for the locking element to exit, ensuring that the locking element can completely disengage from the locking groove to completely cut off the power; the variable diameter section with a gradually changing inner diameter plays a wedge-shaped guiding role during the movement of the sliding sleeve, smoothly converting the axial thrust of the sliding sleeve into the radial pressure of the locking element, reducing the operating resistance and preventing the mechanism from jamming.

[0040] The outer circumferential surface of the sliding sleeve 4 is provided with a driving part for receiving external driving force. In this embodiment, the driving part is constructed as an annular flange protruding outward along the circumference of the sliding sleeve 4. Simultaneously, a reset elastic element 5, which can extend and retract axially along the driving shaft 1, is provided between the driving spindle 1 and the sliding sleeve 4, so that the pressing surface or release surface of the sliding sleeve 4 is located at the locking hole 12 in the initial state of the reset elastic element 5. The reset elastic element provides an axial biasing force, allowing the sliding sleeve to automatically maintain its default state of normally closed (normally engaged) or normally open (normally disengaged) when not driven by external force. This simplifies the design of the external operating mechanism, requiring only the application of a unidirectional driving force to achieve state switching. In other specific embodiments, the driving part can also be constructed as an annular groove recessed along the circumference of the sliding sleeve 4, allowing bidirectional switching via a shift fork.

[0041] like Figure 3 and Figure 4 As shown, an annular limiting plate 6 is fixedly provided at the opening end of the receiving cavity 11. The outer diameter of the limiting plate 6 is larger than the outer diameter of the shaft segment where the receiving cavity 11 is located. The reset elastic member 5 is located on the side of the sliding sleeve 4 away from the limiting plate 6, and the other end of the sliding sleeve 4 abuts against the limiting plate 6 in the initial state of the reset elastic member 5. At the same time, the inner diameter of the limiting plate 6 is smaller than the inner diameter of the receiving cavity 11. One end of the output shaft 2 passing through the limiting plate 6 is a small-diameter shaft segment 22. A shoulder is formed between the small-diameter shaft segment 22 and the main body of the output shaft 2. The shoulder is located inside the receiving cavity 11 and can rotatably abut against the side of the limiting plate 6 facing the inside of the receiving cavity 11.

[0042] The large outer diameter of the limiting plate forms the axial travel stop of the sliding sleeve, preventing it from disengaging from the drive shaft under spring force. Simultaneously, the limiting plate provides a necessary reference position for the spring return system, ensuring initial stability. Furthermore, the limiting plate serves a dual limiting function for both the sliding sleeve and the output shaft. By utilizing the small inner diameter of the limiting plate in conjunction with the shoulder of the output shaft, the output shaft is physically restricted from disengaging from the receiving cavity without the need for additional locking nuts or pins. Moreover, during clutch operation, this limiting fit consistently fixes the output shaft in its axial position, ensuring that it does not axially move due to clutch disengagement, thus guaranteeing a constant fit depth and support rigidity between the output shaft and the drive shaft.

[0043] In this embodiment, in the steering clutch transmission system, the two accommodating cavities 11 on the drive spindle 1 are axially connected; the opposite ends of the two output shafts 2 are connected through a rotatable shaft hole fitting structure to form a load-bearing beam; the outer ends of the two output shafts 2 are equipped with travel bearings, which are rotatably supported on the wall of the travel box, and the drive spindle 1 is rotatably mounted on the load-bearing beam formed by the two output shafts 2. This overturns the traditional force-bearing mode of micro-tillers, where the box supports the spindle and the spindle cantilever supports the wheel axle. This solution interconnects the two output shafts to form an integral load-bearing beam spanning the travel box, and directly supports this load-bearing beam on the box wall through travel bearings, allowing the huge bending moment load from the wheels to be directly transmitted to the box. The drive spindle, in a "floating" state, is mounted on the load-bearing beam formed by the output shafts, only responsible for transmitting torque and no longer bearing the bending moment load from the wheels. This structure greatly improves the overall rigidity and bending resistance of the shaft system without increasing the size of the box, fundamentally solving the risk of axle breakage during heavy-load tillage.

[0044] Specifically, such as Figure 3 and Figure 4 As shown, the shaft-hole mating structure includes an inner support shaft 9 and inner support holes 23 respectively opened at opposite ends of the two output shafts 2. The inner support holes 23 are coaxially arranged on the output shafts 2, and both ends of the inner support shaft 9 are rotatably inserted into the two inner support holes 23. By using the inner support shaft as an intermediate connector, the two independent output shafts on the left and right are precisely aligned and connected at their geometric centers, forming the physical basis of the aforementioned load-bearing beam, while ensuring that the left and right output shafts can rotate independently to achieve differential speed or unilateral parking steering.

[0045] To prevent the two output shafts from pushing against each other, a retaining ring is provided between the two output shafts 2. The retaining ring is protrudingly disposed on the inner wall of the receiving cavity 11 of the drive main shaft 1 or in the middle of the inner support shaft 9. In this embodiment, the retaining ring is located in the middle of the inner support shaft 9. This provides an axial thrust reference between the two output shafts, preventing excessive inward movement of the two output shafts under the action of lateral force from the wheel, and ensuring the stability of the axial clearance of the internal components of the clutch.

[0046] Furthermore, each of the two output shafts 2 has a support shaft section 24 formed at its opposite end. The outer diameter of the support shaft section 24 matches the inner diameter of the receiving cavity 11. The drive spindle 1 is rotatably supported on the support shaft sections 24 of the two output shafts 2 through the inner wall of the receiving cavity 11. This provides a specific physical interface for the "floating" installation of the drive spindle. By using the support shaft section at the inner end of the output shaft as a sliding bearing surface, the coaxiality between the drive spindle and the output shaft is ensured, achieving smooth operation of the floating support.

[0047] When the micro-tiller of this embodiment is in operation, after the micro-tiller engine is started, the power is transmitted to the drive gear 13 through the gearbox, which drives the drive shaft 1 to rotate.

[0048] 1. Straight-line driving state (normally closed mode): When no steering operation is performed, both sliding sleeves 4 on the left and right sides are held at their extreme positions near the limit plate 6 under the elastic force of the reset elastic element 5. At this time, the first cylindrical surface (pressing surface) of the inner wall of the sliding sleeve 4 covers the locking hole 12, forcibly pressing the locking element 3 (ball) into the spline locking groove 21 of the output shaft 2. The torque of the drive shaft 1 is simultaneously transmitted to the left and right output shafts 2 through the locking element 3, driving the two walking wheels on both sides to rotate synchronously, and the tiller moves forward in a straight line. During this process, the left and right output shafts 2 are connected into a whole beam through the inner support shaft 9, which jointly bears the bending moment load from the ground, while the drive shaft 1 only floats to transmit torque.

[0049] 2. Steering Operation (Taking Left Turn as an Example): When the operator squeezes the left steering handle, the resistance of the reset elastic element 5 is overcome by the cable or push rod mechanism, pulling the left sliding sleeve 4 inward (away from the limit plate 6). After the sliding sleeve 4 moves a certain distance, the second cylindrical surface (release surface) of its inner wall aligns with the locking hole 12, and the locking element 3 loses the radial forced constraint from the inner wall of the sliding sleeve 4. At this time, under the centrifugal force generated by the high-speed rotation of the drive shaft 1, and under the relative rotation (rolling) squeezing action between the output shaft 2 and the drive shaft 1 due to the load difference, the locking element 3 (ball) will automatically move outward radially, quickly disengage from the locking groove 21 of the output shaft 2, and fall into the clearance space formed between the second cylindrical surface and the receiving cavity 11. The power on the left side is then cut off, the left output shaft 2 loses driving force (or stops rotating with the brake), while the right output shaft 2 continues to maintain drive, and the tiller uses the speed difference between the left and right wheels to achieve left turn.

[0050] 3. Reset State: After the steering is completed, the operator releases the handle, and the reset elastic element 5 pushes the left sliding sleeve 4 to reset. The variable diameter section of the inner wall of the sliding sleeve 4 contacts and pushes the locking element 3. If the locking element 3 is aligned with the spline tooth tip at this time, it will first fall into the shallower transition ring groove; as the output shaft 2 rotates relative to it, once the locking element 3 is aligned with the locking groove 21, it will be quickly pressed into the groove under the wedge force of the variable diameter section, restoring power transmission.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A drive shaft structure for a micro-tiller, characterized in that, The system includes a drive spindle (1), on which a drive gear (13) for inputting power is coaxially fixedly arranged, and a receiving cavity (11) is coaxially through-equipped; output shafts (2) are symmetrically inserted at both ends of the receiving cavity (11); the opposite ends of the two output shafts (2) are connected by a shaft hole mating structure that can rotate relative to each other to form a bearing beam; the drive spindle (1) is rotatably mounted on the bearing beam formed by the two output shafts (2), and a clutch mechanism is provided between each output shaft (2) and the drive spindle (1).

2. The micro-tiller travel drive shaft structure as described in claim 1, characterized in that, The shaft-hole mating structure includes an inner support shaft (9) and inner support holes (23) respectively opened at opposite ends of the two output shafts (2). The inner support holes (23) are coaxially arranged on the output shafts (2), and the two ends of the inner support shaft (9) are rotatably inserted into the two inner support holes (23).

3. The micro-tiller travel drive shaft structure as described in claim 2, characterized in that, A limiting ring is provided between the two output shafts (2), the limiting ring being provided protrudingly on the inner wall of the receiving cavity (11) of the drive spindle (1) or in the middle of the inner support shaft (9).

4. The micro-tiller travel drive shaft structure as described in claim 1, characterized in that, Each of the two output shafts (2) has a support shaft section (24) formed at one end opposite to the other. The outer diameter of the support shaft section (24) matches the inner diameter of the receiving cavity (11). The drive shaft (1) is rotatably supported on the support shaft section (24) of the two output shafts (2) through the inner wall of the receiving cavity (11).

5. The micro-tiller travel drive shaft structure as described in claim 1, characterized in that, An annular limiting plate (6) is fixedly provided at the opening end of the receiving cavity (11). The inner diameter of the limiting plate (6) is smaller than the inner diameter of the receiving cavity (11). One end of the output shaft (2) passing through the limiting plate (6) is a small diameter shaft section (22). A shoulder is formed between the small diameter shaft section (22) and the main body of the output shaft (2). The shoulder is located inside the receiving cavity (11) and can rotate relative to the side of the limiting plate (6) facing the inside of the receiving cavity (11).

6. A micro-tiller, comprising a travel box, characterized in that, The walking box is equipped with a micro-tiller walking drive shaft structure as described in any one of claims 1 to 5. In the micro-tiller walking drive shaft structure, the outer ends of the two output shafts (2) are equipped with walking bearings, which are rotatably supported on the box wall of the walking box.

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