A drive assembly and a cart

Abstract

The application relates to the electric vehicle technical field and provides a driving assembly and a carrier, the driving assembly comprising a motor, a shell, a first reduction gear set, a differential gear assembly, a second reduction gear set and a driving wheel, the driving wheel comprising an axle and a wheel body; the differential gear assembly comprising: a main shaft, the two ends of the main shaft being fixed with the inner wall of the shell respectively; an input gear, the middle of the input gear being provided with a shaft hole for the main shaft to pass through, the input gear being rotatably arranged on the main shaft, the peripheral wall of the input gear being provided with gear teeth which are engaged with the first reduction gear set, the input gear being provided with a pair of mounting ports on the opposite sides of the shaft hole, a short shaft being arranged in each of the mounting ports, and the two short shafts being collinear; a driving gear, the driving gear being rotatably arranged on the short shaft; a driven gear, the driven gear being sleeved on the main shaft, one end of the driven gear being engaged with the driving gear in pairs, and the other end of the driven gear being in transmission connection with the second reduction gear set; the number of parts and the structure are simplified, the abrasion is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, specifically to a drive assembly and a transport vehicle. Background Technology

[0002] Electric pallet trucks, as tools for point-to-point transport on a flat surface, are suitable for almost any situation due to their compact and flexible size. Chinese patent number 210062674 discloses a pallet truck whose drive assembly includes a motor, left and right sets of drive wheels, and a differential. The differential includes a housing, a first reduction gear set (i.e., power input shaft, first bevel gear, second bevel gear, and transmission gear), a differential, and a second reduction gear set (i.e., half-shaft transmission gear and drive gear). This drive assembly directly adopts the spherical differential commonly used in automobiles.

[0003] like Figure 1 and 2 As shown, the spherical differential includes an input gear 420, a pair of driving gears 480, and a pair of driven gears 490. Both the driving gears 480 and the driven gears 490 are bevel gears, and they perform different functions due to their different installation positions. A through hole is provided in the middle of the input gear 420 for housing the pair of driving gears 480. The fixed shaft 413 of this pair of driving gears 480 is fixed inside the input gear 420, and the shaft passes through the center of the input gear 420 (i.e., the shaft is on the diameter of the gear). The other pair of driven gears 490 are disposed on the axis of the input gear 420 (perpendicular to the side of the gear). Hemispherical side covers 465 are provided on both sides of the input gear 420, fixing the pair of driven gears 490 located on the axis of the input gear 420 within the space enclosed by the hemispherical side covers 465, so that these four bevel gears mesh. The pair of driven gears located on the input gear axis output power (to the second reduction gear set) through a pair of half-shafts 412 (the half-shafts protrude from the hemispherical side cover). These half-shafts are fixed to the housing by bearings. During manufacturing and assembly, if production or assembly errors are too large, the two half-shafts may become misaligned (i.e., their rotation centers are not collinear). This will affect the bevel gears (driven gears) mounted on these half-shafts, as well as the hemispherical side cover and input gear that provide positioning via the bevel gears (driven gears), potentially leading to poor tooth meshing. If the differential operates under these conditions for an extended period, it may cause gear wear, shortening its service life and affecting the stable operation of the differential. This is especially problematic when the transport vehicle is under heavy load, which can exacerbate the issue. Furthermore, the bevel gears are enclosed within the hemispherical side cover; when the bevel gears wear down, operators must remove the side cover to perform operations, causing inconvenience for inspection, maintenance, or replacement.

[0004] Furthermore, because the pallet truck carries a large load during daily operation, and the two drive wheels are connected by an axle, the truck frame has support feet at the bottom. These support feet are made of large-diameter cylinders. The axle is horizontally positioned, and the cylinder is vertically positioned. A circular hole (the diameter of which matches the axle size, or a semi-circular groove) is cut into the side of the cylinder's bottom for the axle to pass through. The two are then secured with bolts or pins. In this connection structure between the support feet and the axle, the contact surface between the cylinder and the axle is curved. Since the weight of the cylinder on the axle is always vertically downward (statically), the pressure on different parts of the contact surface varies. This uneven pressure over time will cause different deformations due to the varying pressure, thus affecting the service life. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome at least the short service life of the differential in the drive assembly of the transport vehicle in the above-mentioned related technologies, and to provide a drive assembly and transport vehicle with a long service life.

[0006] To achieve the above objectives, the present invention provides a first aspect through the following technical solution: a drive assembly comprising:

[0007] An electric motor is used to provide power;

[0008] The outer shell has a receiving cavity;

[0009] The first reduction gear set is disposed in the receiving cavity and is connected to the motor drive to improve the output torque of the motor;

[0010] A differential gear assembly is disposed within the receiving cavity and is connected in transmission to the first reduction gear set;

[0011] The second reduction gear set is connected to the differential gear assembly for transmission; and...

[0012] The drive wheel includes an axle and wheel bodies located at both ends of the axle and capable of rotating independently of each other. The axle is fixed to the housing, and the wheel bodies are connected to the second reduction gear set for transmission.

[0013] The differential gear assembly includes:

[0014] The main shaft is fixed at both ends to the inner wall of the outer casing;

[0015] An input gear has a central shaft hole through which the main shaft passes. The input gear is rotatably mounted on the main shaft. The peripheral wall of the input gear has teeth that mesh with the first reduction gear set. The input gear has a pair of mounting holes on opposite sides of the shaft hole. A short shaft is provided in each mounting hole, and the two short shafts are collinear.

[0016] A pair of drive gears are provided, each rotatably mounted on the short shaft;

[0017] A pair of driven gears are provided, which are sleeved on the main shaft and located on both sides of the input gear. One end of the driven gear meshes with the driving gear in pairs, and the other end of the driven gear is connected to the second reduction gear set for transmission.

[0018] By setting up a main shaft and mounting two driven gears on it, the two driven gears can be kept concentric. Furthermore, by fixing both ends of the main shaft inside the housing, the components and structure can be simplified (no hemispherical side cover). This reduces the adverse effects of assembly errors involving multiple parts. On the one hand, improved assembly accuracy allows for smoother operation of components, reducing wear and extending service life; on the other hand, it also improves assembly efficiency. In addition, since the hemispherical side cover is removed, the meshing point of the driving and driven gears is directly visible, facilitating inspection and maintenance.

[0019] A further embodiment of the present invention is as follows: the outer shell includes a first shell and a second shell fixed together; one end of the main shaft is fixed to the first shell, and the other end of the main shaft is fixed to the second shell.

[0020] A further aspect of the present invention is as follows: the inner walls of both the first housing and the second housing are provided with grooves for mounting the spindle, and a limiting pin is provided between the end of the spindle and the groove to restrict the circumferential rotation of the spindle.

[0021] A further aspect of the present invention is that the depth of the groove is greater than the thickness of the first housing and the second housing, and the bottom of the groove protrudes outward from the outer wall of the first housing and the second housing.

[0022] This design allows for the fixation of the spindle without increasing the overall thickness or width of the housing, thereby reducing the amount of material used in the housing during production and lowering production costs.

[0023] A further embodiment of the present invention is that the motor includes a motor shaft;

[0024] The first reduction gear set includes:

[0025] A first gear is disposed on the motor shaft; and,

[0026] The second gear is located between the first gear and the input gear teeth;

[0027] The second gear is a double gear, including a large-diameter end and a small-diameter end, wherein the large-diameter end meshes with the first gear, and the small-diameter end meshes with the gear teeth.

[0028] A further aspect of the present invention is that the second reduction gear set includes:

[0029] A third gear is rotatably mounted on the main shaft, and the third gear is fixed to the driven gear; and,

[0030] A fourth gear is rotatably mounted on the axle; the fourth gear is fixed to the wheel body;

[0031] The fourth gear has a greater number of teeth than the third gear.

[0032] By also mounting the third gear on the main shaft, the input gear, two driven gears, and two third gears can be installed on a single main shaft, resulting in a high degree of integration, reduced redundant parts, and lower costs.

[0033] A further embodiment of the present invention is that the input gear includes a body formed by forging and an insert disposed on the body;

[0034] At least one end face on one side of the body has a recess for punching out a first mounting hole for mounting a bevel gear.

[0035] The insert is embedded in the recess and fastened thereto, and the insert has a second mounting hole that is aligned with the first mounting hole.

[0036] This design strengthens the recessed area on the wheel body through forging, allowing its thickness to be controlled at around 5mm (reducing the thickness by at least half) to meet or even exceed the original requirements, facilitating the installation through the punched mounting holes. After the drive gear is installed into the mounting holes, the forged reinforcement of the recessed area results in high contact surface strength, reducing wear and extending service life. Simultaneously, a metal plate is embedded in the recessed area, which, through the two mounting holes, effectively secures the drive gear. The insert structure is simple, facilitating production, easy assembly, and high production efficiency.

[0037] A further aspect of the present invention is that the recess is circular in shape and is concentrically arranged with the body; the outer hub of the insert is adapted to the recess.

[0038] A further aspect of the present invention is that: an annular step is provided around the periphery of the recess, and the annular step abuts against the end face of one side of the insert, so that the bottom surface of the recess is separated from the end face of one side of the insert.

[0039] A further aspect of the present invention is as follows: an integrally formed bushing is provided in the middle of the main body, and the first mounting holes are respectively provided on both sides of the bushing and are arranged opposite to each other.

[0040] A further aspect of the present invention is that the insert has a bushing hole in the middle through which the bushing passes; the insert is positioned and installed by cooperating with the bushing through the bushing hole.

[0041] A further embodiment of the present invention is that the second mounting hole is connected to the bushing hole.

[0042] A further embodiment of the present invention is that the two ends of the bushing extend outward and protrude from the surfaces of the two ends of the input gear, respectively.

[0043] In a second aspect, the present invention also provides a transport vehicle, including a frame assembly, a lifting mechanism assembly, an operating lever assembly, and a drive assembly as described in the first aspect; the lifting mechanism assembly and the operating lever assembly are disposed on the frame assembly, and the axle is provided with a connecting portion integrally formed with the axle, the connecting portion having at least one first support plane;

[0044] The lifting mechanism assembly is provided with a support foot, and the support foot is provided with a lower connecting end for connecting with the connecting part. The lower connecting end is provided with a second connecting plane that is equal in number to and opposite to the first support plane.

[0045] The axle's axis is parallel to the first support plane; the axle's supporting force on the support foot passes perpendicularly through the first support plane and the second connecting plane, so as to distribute the supporting force evenly on the contact surface between the two.

[0046] The above solution involves setting two planes between the axle and the support foot to transmit gravity and support force. The interaction force at each point of the contact surface acts perpendicularly to the plane (in the prior art, a curved surface), which can distribute the force more evenly, reduce the deformation difference caused by different pressures, thereby reducing the impact of deformation difference on the contact surface on the axle and thus improving its service life.

[0047] In summary, this invention has the following beneficial effects: By setting a main shaft and mounting two driven gears on this main shaft, the two driven gears can remain concentric. Furthermore, by fixing both ends of the main shaft within the housing, the components and structure can be simplified (no hemispherical side cover), thereby reducing the adverse effects of assembly errors involving multiple parts. On the one hand, improved assembly accuracy allows for smoother operation of components, reducing wear and extending service life; on the other hand, it also improves assembly efficiency. In addition, since the hemispherical side cover is removed, the meshing point of the driving and driven gears is directly visible, facilitating inspection and maintenance. The recesses on the wheel body are strengthened through forging, allowing their thickness to be controlled at around 5mm (thickness reduced by at least 1 / 2) to meet or even far exceed the original requirements, facilitating the installation through punched mounting holes. After the driving gear is installed in the mounting hole, the forged reinforcement of the recesses results in high contact surface strength, reducing wear and extending service life. Simultaneously, metal sheets are embedded in the recesses, which, through the two mounting holes, effectively secure the driving gear. The insert structure is simple, which not only facilitates production but also makes it easy to assemble, resulting in high production efficiency. In addition, two planes are set between the wheel axle and the support foot to transmit gravity and support force. The interaction force at each point of the contact surface acts perpendicularly to the plane (the existing technology uses a curved surface), which can distribute the force more evenly and reduce the deformation difference caused by different pressures. This reduces the impact of the deformation difference on the contact surface on the wheel axle, thereby improving its service life. Attached Figure Description

[0048] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0049] Figure 1 This is an exploded view of a spherical differential in the prior art.

[0050] Figure 2 This is a cross-sectional view of a spherical differential in the prior art on the intersecting plane of the fixed shaft and the half shaft.

[0051] Figure 3 and 4 These are exploded views of the drive assembly described in this invention in different directions.

[0052] Figure 5 This is a cross-sectional view of the drive assembly described in this invention along the plane containing the wheel axle and the main shaft.

[0053] Figure 6 This is a schematic diagram of the structure of the motor, the first reduction gear set, the differential gear assembly, and the second reduction gear set described in this invention, showing the transmission relationship between them.

[0054] Figure 7 This is an exploded view of the input gear teeth described in this embodiment.

[0055] Figure 8 This is the front view of the input gear teeth described in this embodiment.

[0056] Figure 9 yes Figure 8 A cross-sectional view along the A-A direction.

[0057] Figure 10 This is a schematic diagram of the installation of the drive gear on the input gear teeth in this embodiment.

[0058] Figure 11 This is an exploded view of the connection structure between the drive wheel and the support foot.

[0059] Figure 12 This is a side view of the drive wheel and support foot.

[0060] Figure 13 This is a top view of the drive wheel.

[0061] Figure 14 The drive wheel and the support leg are along the Figure 13 Cross-sectional view along the BB direction.

[0062] Wherein: 100, motor; 110, motor shaft; 210, first housing; 220, second housing; 230, groove; 300, first reduction gear set; 310, first gear; 320, second gear; 321, large diameter end; 322, small diameter end; 400, differential gear assembly; 410, main shaft; 412, half shaft; 413, fixed shaft; 420, input gear; 430, shaft hole; 450, short shaft; 460, body; 461, recess; 462, first mounting bracket. Mounting hole; 463, annular step; 464, bushing; 465, side cover; 466, bushing hole; 470, insert; 471, second mounting hole; 480, driving gear; 490, driven gear; 500, second reduction gear set; 510, third gear; 520, fourth gear; 610, wheel axle; 611, connecting part; 612, first support plane; 613, through hole; 620, wheel body; 710, support foot; 711, positioning post; 720, second connecting plane. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0065] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0067] like Figure 3-6 As shown, the present invention provides a drive assembly, which mainly includes a motor 100, a housing 200, a first reduction gear set 300, a differential gear assembly 400, a second reduction gear set 500, and a drive wheel 600.

[0068] The motor 100 provides power. The housing 200 has a receiving cavity for accommodating components. A first reduction gear set 300 is disposed within the receiving cavity and is connected to the motor 100 for increasing the output torque of the motor 100. The motor 100 can be disposed inside or outside the receiving cavity. In this embodiment, the housing 200 has two receiving cavities, one of which is used to install the motor 100.

[0069] The differential gear assembly 400 is also disposed within the receiving cavity and is drive-connected to the first reduction gear set 300. Additionally, the second reduction gear set 500 is drive-connected to the power output end of the differential gear assembly 400. Integrating the first reduction gear set 300, the differential gear assembly 400, and the second reduction gear set 500 into the same receiving cavity fully utilizes the space within the cavity. The drive wheel 600 is disposed outside the housing 200 and is fixed integrally with the housing 200.

[0070] Specifically, the drive wheel 600 includes an axle 610 and wheel bodies 620 located at both ends of the axle 610 and capable of rotating independently. A bearing is provided between the wheel body 620 and the axle 610, and the two can rotate independently through the bearing. The axle 610 is fixed to the housing 200, and the wheel body 620 is connected to the second reduction gear set 500 for transmission.

[0071] More specifically, the differential gear assembly 400 includes a main shaft 410, an input gear 420, a pair of driving gears 480, and a pair of driven gears 490.

[0072] Both ends of the main shaft 410 are fixed to the inner wall of the housing 200. The input gear 420 has a shaft hole 430 in the middle for the main shaft 410 to pass through. The input gear 420 is rotatably mounted on the main shaft 410. The peripheral wall of the input gear 420 has gear teeth that mesh with the first reduction gear set 300. The input gear 420 has a pair of mounting holes on opposite sides of the shaft hole 430. A short shaft 450 is provided in each of the mounting holes, and the two short shafts 450 are collinear.

[0073] Two driving gears 480 are rotatably mounted on the short shaft 450, while two driven gears 490 are sleeved on the main shaft 410 and located on both sides of the input gear 420. One end of each driven gear 490 meshes with a pair of driving gears 480, and the other end of each driven gear 490 is connected to the second reduction gear set 500.

[0074] By setting a main shaft 410 and mounting two driven gears 490 on it, the two driven gears 490 can remain concentric. Furthermore, by fixing both ends of the main shaft 410 within the housing 200, the components and structure can be simplified (without the hemispherical side cover 465), thereby reducing the adverse effects of assembly errors involving multiple parts. On the one hand, improved assembly accuracy allows for smoother component operation, reducing wear and extending service life; on the other hand, it also improves assembly efficiency. Moreover, since the hemispherical side cover 465 is removed, the meshing point of the driving gear 480 and driven gear 490 is directly visible, facilitating inspection and maintenance.

[0075] like Figure 3 , 4 As shown in Figure 5, in an exemplary embodiment, the housing 200 includes a first housing 210 and a second housing 220 fixed together. When the first housing 210 and the second housing 220 are engaged, they form a receiving cavity for accommodating the first reduction gear set 300, the differential gear assembly 400, and the second reduction gear set 500. When the first housing 210 and the second housing 220 are engaged, one end of the main shaft 410 is fixed to the first housing 210, and the other end of the main shaft 410 is fixed to the second housing 220.

[0076] Specifically, the inner walls of the first housing 210 and the second housing 220 are provided with grooves 230 for mounting the main shaft 410, and a limiting pin 240 is provided between the end of the main shaft 410 and the groove 230 to limit the circumferential rotation of the main shaft 410.

[0077] More specifically, the depth of the groove 230 is greater than the thickness of the first housing 210 and the second housing 220, and the bottom of the groove 230 protrudes outward from the outer wall of the first housing 210 and the second housing 220. This configuration allows for the fixation of the spindle 410 without increasing the overall thickness or width of the housing, thereby reducing the material used in housing production and lowering production costs.

[0078] In an exemplary embodiment, the motor 100 includes a stator, a rotor, and a motor shaft 110. A cylindrical outer wall is provided on the first housing 210 (or disposed on the second housing 220), the outer wall extending outward perpendicular to the surface of the first housing 210, and has a circular opening at one of its outer ends to facilitate the insertion of the motor 100. The stator is fixed to the inner side of the outer wall, and the rotor is fixed to the motor shaft 110. One end of the motor shaft 110 is fixed to the open end of the outer wall by a motor cover and a bearing, and the other end of the motor shaft 110 passes through the first housing 210 and extends into the receiving cavity formed between the first housing 210 and the second housing 220.

[0079] In this embodiment, the first reduction gear set 300 includes a first gear 310 and a second gear 320. The first gear 310 is mounted on and fixed to the motor shaft 110, and its rotation drives the first gear 310 to rotate synchronously. The first gear 310 can be an independent gear component assembled onto the motor shaft 110 via splines or pins, or it can be directly machined onto the motor shaft 110 using a lathe. In this embodiment, the first gear 310 is machined onto the motor shaft 110 using a lathe, which reduces the number of parts. Integrating the two into a single unit reduces material usage, costs, and space requirements, and also reduces assembly steps.

[0080] The second gear 320 is disposed between the first gear 310 and the input gear teeth. The second gear 320 reduces the rotational speed and amplifies the output torque. More specifically, the second gear 320 is a double gear, including a large-diameter end 321 and a small-diameter end 322, wherein the large-diameter end 321 meshes with the first gear 310, and the small-diameter end 322 meshes with the gear teeth.

[0081] To further improve the output torque, a second reduction gear set 500 is provided in this embodiment. The second reduction gear set 500 includes a third gear 510 and a fourth gear 520.

[0082] The third gear 510 is rotatably mounted on the main shaft 410 and is fixed to the driven gear 490. The fourth gear 520 is rotatably mounted on the axle 610 and is fixed to the wheel body 620. Furthermore, the fourth gear 520 has a greater number of teeth than the third gear 510 to increase torque; the increase in torque is positively correlated with the ratio of their tooth counts. The specific ratio can be designed by those skilled in the art based on the load and the power of the motor 100, and will not be detailed here.

[0083] Existing input gears are manufactured using powder metallurgy, resulting in high production costs. Furthermore, these gears have low load capacity and are prone to wear. The worn powder mixes with grease, accelerating wear and shortening the gear's lifespan. To save costs, the inventors have improved the design by incorporating metal clips in the mounting holes to increase wear resistance between the holes and mounting blocks. However, this design requires assembling the metal clips and mounting blocks first, then installing them together into the mounting holes. Adjusting the metal clips to ensure proper alignment and installation makes the assembly process cumbersome and inefficient.

[0084] To overcome the shortcomings of existing input gears, which cannot simultaneously achieve both long service life and ease of assembly. For example... Figure 7-10 As shown in the exemplary embodiment, an input gear with a long service life and easy assembly is illustrated. The input gear 420 includes a forged body 460 and an insert 470 disposed on the body 460. The body 460 is cylindrical with teeth on its cylindrical side surface. At least one end face of the body 460 has a recess 461 for punching out a spacer for mounting a drive gear 480 (see Figure 470). Figure 7 The first mounting hole 462 is provided. In this embodiment, an example is given where a recess 461 is provided on one side. The recess 461 is circular and is concentrically arranged with the body 460 (i.e., concentric circles). Of course, both can also adopt other geometric shapes, such as rectangles or regular polygons. It should be noted that during installation, the first mounting hole and the second mounting hole must completely overlap to form the mounting hole for inserting the short shaft.

[0085] The outer hub of the insert 470 is adapted to the recess 461, the insert 470 is embedded in the recess 461, and the periphery of the insert 470 is interference-fitted with the periphery of the recess 461.

[0086] The insert 470 has a second mounting hole 471 aligned with the first mounting hole 462. Both the first mounting hole 462 and the second mounting hole 471 are cross-shaped holes. Positioning can be achieved through the two mounting holes during assembly.

[0087] The recess 461 has an annular step 463 around its periphery. The annular step 463 abuts against one end face of the insert 470, thus separating the bottom surface of the recess 461 from the end face of the insert 470. In other words, the annular step 463 forms a hollow layer between the recess 461 and the insert 470, reducing overall weight, saving materials, and lowering production costs without compromising strength.

[0088] In this embodiment, an integrally formed bushing 464 is provided in the middle of the body 460, and the first mounting hole 462 is provided on both sides of the bushing 464 and is arranged opposite to each other.

[0089] The insert 470 has a bushing hole 466 in the middle through which the bushing 464 passes. The insert 470 is positioned and installed by engaging with the bushing 464 through the bushing hole 466. In this embodiment, the insert 470 is integrally stamped from a sheet metal. The sheet metal used is made of steel, and the stamping and punching process not only increases strength but also allows for one-time forming, resulting in high product precision, high production efficiency, and low cost.

[0090] In this embodiment, the second mounting hole 471 on the insert 470 is connected to the bushing hole 466. This configuration allows for the production of two mounting holes and a bushing hole by punching a single, larger connecting hole, resulting in high production efficiency.

[0091] During production, the main body 460 uses alloy steel as the tooth blank, which is then heat-treated to acquire certain toughness, plasticity, and wear resistance. It is then forged using a forging machine to increase its strength.

[0092] A circular cylindrical protrusion is present in the middle of the body 460, which can be drilled through by a drill bit to form a bushing 464. The two ends of the bushing 464 extend outward, respectively protruding from the surfaces at both ends of the input gear teeth.

[0093] The recess 461 located on one side of the body 460 and the annular step 463 around the recess 461 are also machined using a cutting tool. Both the recess 461 and the annular step 463 are circular for easy machining.

[0094] In order to maintain strength while taking into account subsequent punching processes, the thickness of the recess 461 and the thickness of the insert 470 in this embodiment are both 5±1mm, which is very suitable for punching, resulting in low cost and high precision.

[0095] The recess 461 on the body 460 is strengthened through forging, while its thickness is controlled to around 5mm, facilitating the passage of the mounting hole formed by punching. After the drive gear 480 is installed into the mounting hole, the contact surface strength is high due to the forging reinforcement of the recess 461, making it less prone to wear. Simultaneously, a metal sheet is embedded in the recess 461, which, through the two mounting holes, effectively secures the drive gear 480 (which rotates on a short shaft via bearings; the short shaft is a square shaft). The insert 470 has a simple structure, facilitating production, easy assembly, and high production efficiency.

[0096] Because pallet trucks carry heavy loads during daily operation, and the two drive wheels are connected by an axle, the truck frame has support feet at the bottom. These support feet are made of large-diameter cylinders. The axle is horizontally positioned, and the cylinder is vertically positioned. A circular hole (the diameter of which matches the axle size, or a semi-circular groove) is cut into the side of the cylinder's bottom for the axle to pass through. The two are then secured with bolts or pins. In this connection structure, the contact surface between the cylinder and the axle is curved. Since the weight of the cylinder on the axle is always vertically downward (statically), the pressure on different parts of the contact surface varies. Over time, this uneven pressure causes different deformations, which in turn affects the service life of the pallet truck.

[0097] To ensure uniform force distribution on the contact surfaces between the axle and the support feet, reduce deformation caused by uneven localized stress, and extend service life, this invention also provides a transport vehicle in an exemplary embodiment, including a frame assembly, a lifting mechanism assembly, an operating lever assembly, and a drive assembly as described above. The structures of the frame assembly, lifting mechanism assembly, and operating lever assembly can be found in the drawings of patent number 210062674, which are omitted in this embodiment. The lifting mechanism assembly and operating lever assembly are mounted on the frame assembly. Figure 11-14 As shown, the axle 610 is provided with a connecting part 611 integrally formed with the axle 610, and the connecting part 611 has at least one first support plane 612.

[0098] The lifting mechanism assembly includes a hydraulic cylinder, the lower end of which is a support foot 710. The lower connecting end of the support foot 710 is used to connect to the connecting part 611, and the lower connecting end is provided with a second connecting plane 720 that is equal in number to and opposite to the first supporting plane 612.

[0099] The axle 610 is parallel to the first support plane 612, and the supporting force of the axle 610 on the support foot 710 passes perpendicularly through the first support plane 612 and the second connecting plane 720, so as to distribute the supporting force evenly on the contact surface between the two.

[0100] By setting two nearly horizontal planes between the axle 610 and the support foot 710 to transmit gravity and support force, and the interaction force at each point of the contact surface acts perpendicularly to the plane, the force can be distributed more evenly, reducing the deformation difference caused by different pressures, thereby reducing the impact of deformation difference on the contact surface on the axle 610, and thus improving its service life.

[0101] For ease of description, it is defined that the length direction of the first support plane 612 is parallel to the axis of the wheel axle 610, and the width direction of the first support plane 612 is perpendicular to the axis of the wheel axle 610.

[0102] In order to maximize the area of ​​the first support plane 612 to distribute the load per unit area without increasing the requirements for the material strength of the axle 610, the width of the first support plane 612 should be greater than or equal to the diameter of the axle 610, and the length of the first support plane 612 should be greater than or equal to the width of the first support plane 612.

[0103] In this embodiment, the width and length of the first supporting plane 612 are equal, and it can be square, circular, or annular. Since the supporting foot 710 is made of cylindrical steel, the end face of the lower connecting end is a circular plane.

[0104] The first supporting plane 612 and the second connecting plane 720 are positioned using a concave-convex structure. Specifically, the connecting part 611 has a through hole 613 (or blind hole) on the first supporting plane 612, and the lower connecting end has a positioning post 711 on the second connecting plane 720 that matches the through hole 613 (or blind hole).

[0105] To facilitate the machining of the positioning post 711 and the through hole 613, both the through hole 613 and the positioning post 711 are circular with equal diameters, and both are centrally located. The support foot 710 is perpendicular to the second connecting plane 720, and the positioning post 711 is also perpendicular to the second connecting plane 720.

[0106] To further improve the reliability of the connection, the effective contact area between the first support plane 612 and the second connection plane 720 is greater than the cross-sectional area of ​​the axle 610. The effective contact area is the area through which the supporting force of the axle 610 on the support foot 710 passes vertically.

[0107] It should be noted that the connecting part 611 in this embodiment is cubic in shape, and the outer contour of the first supporting plane 612 is square, with a circular through hole 613 in the middle of the square for inserting the positioning post 711. Correspondingly, the second connecting plane 720 is a toroidal surface, with the side length of the square slightly larger than the outer diameter of the toroidal surface.

[0108] To facilitate understanding, the following specific data is used as an example: the diameter R1 of the axle 610 is 24mm, the side length L of the square is 40mm, the diameter R2 of the through hole 613 is 24mm, the diameter R3 of the support foot 710 is 36mm, and the diameter R4 of the positioning post 711 is 24mm. The effective contact area (annular ring) between the first support surface and the second connecting surface is (18*18-12*12)π, which equals 180π; the cross-sectional area of ​​the axle 610 is 12*12π, which equals 144π; 180π > 144π.

[0109] The reason why the connecting part 611 is shaped like a cube is because the two sides of the cube are vertical planes, which can be used to install other parts. If it were a cylindrical side, it would be difficult to install.

[0110] In this embodiment, the fastener is a first fastener—a bolt—used to fix the connecting part 611 to the lower connecting end. Specifically, the bolt is laterally inserted into the through hole 613 and the positioning post 711 located therein, and is threadedly connected to the connecting part 611 and the positioning post 711 by the bolt to prevent the positioning post 711 from disengaging from the through hole 613.

[0111] In another alternative embodiment, the first fixing member 510 may also use a pin, which is laterally inserted into the through hole 613 and the positioning post 711 located therein. The pin is interference-fitted with the connecting part 611 and the positioning post 711 to achieve fixation. Further details will not be provided here.

[0112] It should be noted that, in another alternative embodiment, a blind hole is provided on the connecting part 611 instead of the through hole 613. Correspondingly, the length of the positioning post 711 is the same as the depth of the blind hole. Therefore, when the positioning post 711 is inserted into the blind hole, the end face of the positioning post 711 fits against the end face of the blind hole. The first supporting plane 612 is formed by the upper end face of the cube and the bottom surface of the blind hole. The second connecting plane is formed by the annular end face of the supporting leg 710 and the circular end face of the positioning post 711. Although the upper end face of the cube, the bottom surface of the blind hole, the annular end face of the supporting leg 710, and the circular end face of the positioning post 711 are not on the same plane, the upper end face of the cube and the bottom surface of the blind hole are parallel to each other, and the annular end face of the supporting leg 710 and the circular end face of the positioning post 711 are also parallel to each other. Furthermore, the upper end face of the cube supports the annular end face of the supporting leg 710, and the bottom surface of the blind hole supports the circular end face of the positioning post 711.

[0113] Therefore, the number, shape, and position of the first supporting plane 612 and the second connecting plane 720 can be adaptively adjusted according to specific circumstances, and are not limited by whether they are on the same plane or connected.

Claims

1. A drive assembly, comprising: An electric motor is used to provide power; The outer shell has a receiving cavity; The first reduction gear set is disposed in the receiving cavity and is connected to the motor drive to improve the output torque of the motor; A differential gear assembly is disposed within the receiving cavity and is connected in transmission to the first reduction gear set; The second reduction gear set is connected to the differential gear assembly for transmission; and... The drive wheel includes an axle and wheel bodies located at both ends of the axle and capable of rotating independently of each other. The axle is fixed to the housing, and the wheel bodies are connected to the second reduction gear set for transmission. The differential gear assembly is characterized in that it comprises: The main shaft is fixed at both ends to the inner wall of the outer casing; An input gear has a central shaft hole through which the main shaft passes. The input gear is rotatably mounted on the main shaft. The peripheral wall of the input gear has teeth that mesh with the first reduction gear set. The input gear has a pair of mounting holes on opposite sides of the shaft hole. A short shaft is provided in each mounting hole, and the two short shafts are collinear. A pair of drive gears are provided, each rotatably mounted on the short shaft; A pair of driven gears are provided, which are sleeved on the main shaft and located on both sides of the input gear. One end of the driven gear meshes with the driving gear in pairs, and the other end of the driven gear is connected to the second reduction gear set for transmission.

2. The drive assembly according to claim 1, characterized in that, The outer casing includes a first housing and a second housing fixed together; one end of the main shaft is fixed to the first housing, and the other end of the main shaft is fixed to the second housing.

3. The drive assembly according to claim 2, characterized in that, The inner walls of both the first housing and the second housing are provided with grooves for mounting the spindle, and a limiting pin is provided between the end of the spindle and the groove to restrict the circumferential rotation of the spindle.

4. The drive assembly according to claim 3, characterized in that, The depth of the groove is greater than the thickness of the first housing and the second housing, and the bottom of the groove protrudes outward from the outer wall of the first housing and the second housing.

5. The drive assembly according to claim 1, characterized in that, The motor includes a motor shaft; The first reduction gear set includes: A first gear is disposed on the motor shaft; and, The second gear is located between the first gear and the input gear teeth; The second gear is a double gear, including a large-diameter end and a small-diameter end, wherein the large-diameter end meshes with the first gear, and the small-diameter end meshes with the gear teeth.

6. The drive assembly according to claim 1, characterized in that, The second reduction gear set includes: A third gear is rotatably mounted on the main shaft, and the third gear is fixed to the driven gear; and, A fourth gear is rotatably mounted on the axle; the fourth gear is fixed to the wheel body; The fourth gear has a greater number of teeth than the third gear.

7. The drive assembly according to claim 1, characterized in that, The input gear includes a body formed by forging and an insert disposed on the body; At least one end face on one side of the body has a recess for punching out a first mounting hole for mounting the drive gear. The insert is embedded in the recess and fastened thereto, and the insert has a second mounting hole that is aligned with the first mounting hole.

8. The drive assembly according to claim 7, characterized in that, The recess is circular in shape and is concentrically arranged on the body; the outer hub of the insert is adapted to the recess.

9. The drive assembly according to claim 7, characterized in that, The recess is provided with an annular step around its perimeter. The annular step abuts against the end face of one side of the insert, thereby separating the bottom surface of the recess from the end face of one side of the insert.

10. The drive assembly according to claim 7, characterized in that, An integrally formed bushing is provided in the middle of the main body, and the first mounting hole is provided on both sides of the bushing and is arranged opposite to each other.

11. The drive assembly according to claim 10, characterized in that, The insert has a bushing hole in the middle through which the bushing passes; the insert is positioned and installed by engaging with the bushing through the bushing hole.

12. The drive assembly according to claim 11, characterized in that, The second mounting hole is connected to the bushing hole.

13. The drive assembly according to claim 10, characterized in that, The two ends of the bushing extend outward, respectively protruding from the surfaces at both ends of the input gear.

14. A transport vehicle, comprising a frame assembly, a lifting mechanism assembly, an operating lever assembly, and a drive assembly as described in any one of claims 1-13; wherein the lifting mechanism assembly and the operating lever assembly are disposed on the frame assembly, characterized in that, The axle is provided with a connecting part integrally formed with the axle, and the connecting part has at least one first support plane; The lifting mechanism assembly is provided with a support foot, and the support foot is provided with a lower connecting end for connecting with the connecting part. The lower connecting end is provided with a second connecting plane that is equal in number to and opposite to the first support plane. The axle's axis is parallel to the first support plane; the axle's supporting force on the support foot passes perpendicularly through the first support plane and the second connecting plane, so as to distribute the supporting force evenly on the contact surface between the two.

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