Balance wheel stabilizing structure and three-way forklift

Abstract

The invention discloses a balance wheel stabilizing structure and a three-way forklift, and relates to the field of three-way forklifts.The balance wheel stabilizing structure comprises a frame, a brake assembly, a wheel carrier, a connecting shaft, a balance wheel, a compression spring and a limiting assembly; the brake assembly is arranged on the side face of the frame and comprises an electromagnetic valve, a hydraulic oil cylinder connected with the electromagnetic valve and a piston rod arranged in the hydraulic oil cylinder. An upper cavity and a lower cavity of the hydraulic oil cylinder are communicated with a hydraulic source through the electromagnetic valve, the piston rod extends out of the hydraulic oil cylinder to be connected with the wheel carrier, the balance wheel is movably connected to the connecting shaft, the wheel carrier is connected with the connecting shaft, the pressure spring is arranged between the hydraulic oil cylinder and the piston rod, and the limiting assembly is connected between the frame and the piston rod to limit the stroke of the piston rod. The electromagnetic valve switches the locking state and the floating state of the balance wheel by opening and closing an oil way of the hydraulic oil cylinder, so that the single balance wheel structure can meet the two requirements of high-stability operation and high-adaptability running at the same time.

Description

Technical Field

[0001] This invention relates to the field of three-way forklift technology, specifically to a balance wheel stabilization structure and a three-way forklift. Background Technology

[0002] Existing three-way forklifts generally fall into two categories regarding drive wheel arrangement: One type is the stand-on three-way forklift, where the drive wheel is offset and connected to the balance wheel on the other side via a multi-link swing bridge. The vehicle has a four-point support structure, with the front load-bearing wheel rigidly connected to the chassis, while the rear drive wheel and balance wheel are flexibly connected to the chassis to avoid slippage caused by a fully rigid connection. The other type is the sit-on three-way forklift and the rider-mounted three-way forklift, both featuring a centrally located drive wheel and a three-point support structure. Both the front load-bearing wheel and the centrally located rear drive wheel are rigidly connected to the chassis, forming a stable triangular structure.

[0003] The four-point structure of the three-way fork has a flexible connection between the drive wheel and the balance wheel to avoid slippage. This provides good passability and shock absorption, but the flexible connection is detrimental to the lateral stability of the three-way fork. When the three-way fork shifts to one side while carrying a load, the overall center of gravity shifts to one side, and the corresponding drive wheel or balance wheel experiences increased force, which will cause the vehicle to tilt and reduce the overall stability of the vehicle. The three-point structure of the three-way fork has an inverted triangular structure. Although the load-bearing wheel and drive wheel are rigidly connected to the vehicle body, when the center of gravity shifts, it is closer to the tipping line of the inverted triangle. To compensate for the lateral stability, the overall weight of the vehicle often needs to be made very large.

[0004] Existing three-way forklifts fail to achieve a good balance between stability, lightweight design, and adaptability to different working conditions in their overall layout. Furthermore, the flexible connection method used in the balance wheels of current three-way forklifts makes it difficult to meet the high requirements for vehicle handling stability under different driving and operating conditions.

[0005] Therefore, there is an urgent need to propose a balance wheel stabilization structure and a three-way forklift. Summary of the Invention

[0006] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a balance wheel stabilization structure and a three-way forklift.

[0007] The objective of this invention can be achieved through the following technical solutions: A balance wheel stabilization structure, comprising: Frame, braking components, wheel frames, connecting axles, balance wheels, compression springs, and limiting components; The braking assembly is disposed on the side of the vehicle frame. The braking assembly includes a solenoid valve, a hydraulic cylinder connected to the solenoid valve, and a piston rod disposed in the hydraulic cylinder. The upper and lower chambers of the hydraulic cylinder are connected to the hydraulic source via solenoid valves. The piston rod extends out of the hydraulic cylinder and is connected to the wheel frame. The balance wheel is movably connected to the connecting shaft. The wheel frame is connected to the connecting shaft. The compression spring is disposed between the hydraulic cylinder and the piston rod. The limiting component is connected between the frame and the piston rod to limit the stroke of the piston rod. The solenoid valve switches between the locked and floating states of the balance wheel by switching the oil circuit of the hydraulic cylinder.

[0008] As a further aspect of the present invention: the hydraulic cylinder has an annular groove inside, the piston rod has a radially extending protrusion, the compression spring is sleeved on the piston rod, and the two ends of the compression spring are respectively connected to the inner wall of the groove and the protrusion.

[0009] As a further aspect of the present invention: the limiting component includes a fixed seat mounted on the vehicle frame and connected to the housing of the hydraulic cylinder, a fixed sleeve connected to the fixed seat, a connecting block connected to the inner side of the fixed sleeve, a limiting member located inside the fixed sleeve, and a mating member disposed on the piston rod near the wheel frame. At least two connecting blocks are arranged in a ring within the fixed sleeve. A first slot is provided on the side of the connecting block facing the limiting member. The limiting member is engaged in the first slot and is used to abut against the mating member to limit the stroke of the piston rod.

[0010] As a further aspect of the present invention: the limiting member includes a connecting ring snapped onto the connecting block and a shaped member axially fixedly connected to the connecting ring, the shaped member having a first inclined surface, and the mating member having a second inclined surface that matches the shape of the first inclined surface.

[0011] As a further aspect of the present invention: the connecting ring and the irregular part are integrally formed and both are made of wear-resistant and elastic material.

[0012] As a further aspect of the present invention: at least three irregularly shaped parts are provided and are arranged in a ring around the central axis of the connecting ring, and the irregularly shaped parts have a contact surface facing the piston rod, the shape of the contact surface matching the circumferential surface of the piston rod; When the second inclined surface abuts against the first inclined surface, the abutting surface is in close contact with the circumferential surface of the piston rod.

[0013] As a further aspect of the present invention: a second groove is formed on the circumferential surface of the piston rod, and a snap ring nested in the second groove is fixedly connected to the inner side of the mating part.

[0014] As a further aspect of the present invention: a limiting cavity is formed inside the fixed sleeve, and the connecting block and the irregular part are both located inside the limiting cavity.

[0015] As a further aspect of the present invention: a connecting member is installed on the wheel frame, one end of the piston rod is fixedly sleeved in the connecting member, and a retaining ring is embedded in the end of the piston rod, the retaining ring protruding from the radial outer surface of the piston rod to prevent the wheel frame from falling off.

[0016] A three-way forklift, including a balance wheel stabilization structure as described in any of the preceding descriptions, comprising: The vehicle body includes a drive wheel located at the bottom front side of the vehicle body and two symmetrically distributed load-bearing wheels located at the bottom rear side of the vehicle body. The balance wheel stabilizing structure is provided in two symmetrical configurations, which are respectively located on the left and right sides of the vehicle body and on both sides of the drive wheel. The vehicle frame is connected to the vehicle body. The drive wheel, two balance wheels, and two load-bearing wheels provide symmetrical five-point support for the vehicle body.

[0017] The beneficial effects of this invention are: 1. The stabilizing structure of this balance wheel controls the opening and closing of the hydraulic oil circuit through a solenoid valve to lock or release the piston rod. In the locked state, a closed oil chamber is formed in the hydraulic cylinder. The incompressibility of the oil makes the balance wheel, wheel frame, piston rod and frame a rigid whole, thus overcoming the defects of insufficient lateral support and easy tilting of the vehicle body caused by the soft connection of the balance wheel in the four-point forklift in the background technology. In the floating state, the oil circuit is open, and the piston rod can compress or release the compression spring along the axis, so that the balance wheel produces vertical elastic displacement. While absorbing the impact of the road surface, it maintains the tire ground pressure and retains the anti-slip performance of the soft connection. This allows a single balance wheel structure to meet the two requirements of high stability operation and high adaptability driving at the same time. In addition, the limit component provides a stop when the piston rod moves to the set position, thereby preventing it from overtravel when the hydraulic control fails.

[0018] 2. This three-way forklift increases the lateral support points by placing two stabilizing balance wheels on either side of the drive wheels. When performing operations that easily cause lateral shift of the center of gravity, the locked balance wheels, drive wheels, and load-bearing wheels together form a stable rigid support plane, fundamentally overcoming the deficiency of insufficient lateral support rigidity in traditional four-point structures. At the same time, since the support state of the balance wheels can be quickly switched by controlling the solenoid valve to be energized and de-energized as needed, the vehicle does not need to rely on increasing the overall mass to obtain stability like the traditional three-point structure. This effectively solves the contradiction between lightweight and stability in the design of three-way forklifts. The five-point support structure design of this invention enables the three-way forklift to maintain flexibility and lightness under complex working conditions, while also having sufficient anti-tilt and anti-torsional deformation capabilities. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the balance wheel stabilizing structure of the present invention; Figure 2 This is the invention Figure 1 Enlarged view of point A in the image; Figure 3 This is a partial cross-sectional schematic diagram of the limiting component of the present invention; Figure 4 This is a schematic diagram of the limiting state of the limiting component of the present invention (cross-sectional view). Figure 5 This is a schematic diagram of the unlimited state of the cross-sectional view of the limiting component of the present invention; Figure 6 This is a side view of the irregularly shaped part of the present invention; Figure 7 This is a front view of the three-way forklift of the present invention; Figure 8 This is a schematic diagram showing the distribution of the drive wheels, load-bearing wheels, and balance wheels of the three-way forklift of the present invention; Figure 9 This is a schematic diagram illustrating the principle of the electromagnetic valve controlling the hydraulic cylinder of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 1. Frame; 2. Braking assembly; 4. Wheel frame; 5. Connecting shaft; 6. Balance wheel; 7. Compression spring; 3. Limiting assembly; 21. Solenoid valve; 22. Hydraulic cylinder; 23. Piston rod; 221. Groove; 231. Protrusion; 31. Fixing seat; 32. Fixing sleeve; 33. Connecting block; 34. Limiting component; 35. Mating component; 321. First slot; 341. Connecting ring; 342. Irregular part; 342a. First inclined surface; 351. Second inclined surface; 342b. Contact surface; 352. Second slot; 353. Snap ring; 322. Limiting cavity; 41. Connecting component; 42. Retaining ring; 8. Vehicle body; 81. Drive wheel; 82. Load-bearing wheel. Detailed Implementation

[0022] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] See Figures 1-2 and Figure 9An embodiment of the present invention provides a stabilizing structure for a balance wheel, comprising: a frame 1, a braking assembly 2, a wheel frame 4, a connecting shaft 5, a balance wheel 6, a compression spring 7, and a limiting assembly 3; the braking assembly 2 is disposed on the side of the frame 1, and includes a solenoid valve 21, a hydraulic cylinder 22 connected to the solenoid valve 21, and a piston rod 23 disposed within the hydraulic cylinder 22; both the upper and lower chambers of the hydraulic cylinder 22 are connected to a hydraulic source via the solenoid valve 21, the hydraulic source being a hydraulic oil tank mounted on the frame 1, and the piston rod 23 extending... The hydraulic cylinder 22 is connected to the wheel frame 4, the balance wheel 6 is movably connected to the connecting shaft 5, the wheel frame 4 is connected to the connecting shaft 5, the compression spring 7 is set between the hydraulic cylinder 22 and the piston rod 23, and the limiting component 3 is connected between the frame 1 and the piston rod 23 to limit the stroke of the piston rod 23. When the hydraulic cylinder 22, the compression spring 7, or the solenoid valve 21 fails, it plays a safety role for this structure. The solenoid valve 21 switches the locking state and floating state of the balance wheel 6 by switching the oil circuit of the hydraulic cylinder 22.

[0024] Specifically, when the balance wheel 6 needs to adapt to road undulations, the solenoid valve 21 is de-energized, the oil circuit is connected, and the piston rod 23 of the hydraulic cylinder 22 can move freely up and down under external force. At this time, due to the presence of the compression spring 7, the balance wheel 6 is equivalent to a flexible connection with the frame 1 and has a certain shock absorption capacity, forming a floating state of the balance wheel 6, resulting in good vehicle passability and comfort. When the balance wheel 6 needs to provide rigid support, the solenoid valve 21 is energized, the oil circuit is closed, and the upper and lower chambers of the hydraulic cylinder 22 are filled with hydraulic oil. Due to the incompressible nature of hydraulic oil, the closed hydraulic oil locks the piston rod 23, thereby placing the wheel frame 4 and the balance wheel 6 connected to the piston rod 23 in a fixed position, forming a locked state of the balance wheel 6.

[0025] Furthermore, this balance wheel stabilization structure controls the opening and closing of the hydraulic oil circuit through the solenoid valve 21 to lock or release the piston rod 23. In the locked state, a closed oil chamber is formed in the hydraulic cylinder 22. The incompressibility of the oil makes the balance wheel 6, wheel frame 4, piston rod 23 and frame 1 a rigid whole, thereby overcoming the defects of insufficient lateral support and easy tilting of the vehicle body 8 caused by the soft connection of the balance wheel 6 in the four-point forklift in the prior art. In the floating state, the oil circuit is connected, and the piston rod 23 can compress or release the compression spring 7 along the axis, so that the balance wheel 6 produces vertical elastic displacement. While absorbing the impact of the road surface, it maintains the tire ground pressure and retains the anti-slip performance of the soft connection. This allows the single balance wheel 6 structure to meet the two requirements of high stability operation and high adaptability driving at the same time. In addition, the limiting component 3 provides a blockage when the piston rod 23 moves to the set position, thereby preventing it from overtravel when the hydraulic control fails.

[0026] See Figures 1-2Optionally, the hydraulic cylinder 22 has an annular groove 221 inside, and the piston rod 23 has a radially extending protrusion 231. The compression spring 7 is sleeved on the piston rod 23, and the two ends of the compression spring 7 are connected to the inner wall of the groove 221 and the protrusion 231 respectively. When the piston rod 23 moves, the protrusion 231 compresses or releases the compression spring 7. The compression spring 7 provides elastic buffer for the piston rod 23, the wheel frame 4 and the balance wheel 6 as a whole.

[0027] See Figures 1-5 Optionally, the limiting component 3 includes a fixed base 31 mounted on the frame 1 and fixedly connected to the housing of the hydraulic cylinder 22, a fixed sleeve 32 fixedly connected to the fixed base 31, a connecting block 33 fixedly connected to the inner side of the fixed sleeve 32, a limiting member 34 located inside the fixed sleeve 32, and a mating member 35 disposed on the piston rod 23 near the wheel frame 4; at least two connecting blocks 33 are provided and are arranged in a ring inside the fixed sleeve 32, and a first slot 321 is opened on the side of the connecting block 33 facing the limiting member 34, the limiting member 34 is engaged in the first slot 321, the limiting member 34 is fixed in the fixed sleeve 32 by the multiple connecting blocks 33, and the limiting member 34 is used to abut against the mating member 35 to limit the stroke of the piston rod 23.

[0028] In this embodiment, when the balance wheel 6 is in normal use, the mating part 35 does not abut against the limiting part 34, and the limiting component 3 does not affect the normal use of the balance wheel 6. When the compression spring 7 or the hydraulic cylinder 22 fails, the mating part 35 abuts against the limiting part 34 to limit the stroke of the piston rod 23 and prevent the piston rod 23 from continuing to move. This achieves mechanical limiting of the axial stroke of the piston rod 23, avoids damage to components caused by the overtravel of the piston rod 23 under hydraulic system failure or impact load, and enhances the safety and durability of the system.

[0029] See Figures 1-5 Optionally, the limiting member 34 includes a connecting ring 341 that is snapped onto the connecting block 33 and a shaped member 342 that is axially connected to the connecting ring 341. The shaped member 342 has a first inclined surface 342a, and the mating member 35 has a second inclined surface 351 that matches the shape of the first inclined surface 342a.

[0030] In this embodiment, the irregular part 342 is used to cooperate with the mating part 35 to limit the piston rod 23, and the surface contact of the first inclined surface 342a and the second inclined surface 351 disperses the contact force along the inclined surface, reducing local stress concentration.

[0031] See Figures 1-5Optionally, the connecting ring 341 and the irregular part 342 are integrally formed and both are made of wear-resistant elastic material. In this embodiment, the connecting ring 341 and the irregular part 342 are made of polyurethane rubber with high hardness, so that the irregular part 342 can undergo controllable elastic deformation when in limiting contact, which not only buffers the impact, but also maintains a tight fit with the mating part 35 through elastic restoring force.

[0032] See Figures 1-6 Optionally, at least three irregularly shaped parts 342 are provided and are arranged in a ring around the central axis of the connecting ring 341. In this embodiment, four irregularly shaped parts 342 are provided. The irregularly shaped parts 342 have a contact surface 342b facing the piston rod 23. The shape of the contact surface 342b matches the circumferential surface of the piston rod 23. When the second inclined surface 351 abuts against the first inclined surface 342a, the contact surface 342b is in close contact with the circumferential surface of the piston rod 23.

[0033] In this embodiment, when the second inclined surface 351 of the mating part 35 abuts against the first inclined surface 342a of the irregular part 342, the contact surface 342b of the irregular part 342 simultaneously adheres tightly to the surface of the piston rod 23. While the piston rod 23 is axially limited by the cooperation of the first inclined surface 342a and the second inclined surface 351, the piston rod 23 is radially gripped by the contact surfaces 342b of the three irregular parts 342 distributed in a ring. This not only prevents the piston rod 23 from radially shaking or swaying at the moment of limiting, but also provides additional damping by increasing friction, making the limiting action more stable and precise.

[0034] Furthermore, by using a connecting ring 341 made of high-hardness polyurethane rubber and a shaped part 342, the shaped part 342 can undergo controllable elastic deformation during limiting contact. The piston rod 23 is gradually limited axially through the cooperation of the first inclined surface 342a and the second inclined surface 351, and the outer surface of the piston rod 23 is radially limited in a ring-like manner through the contact surface 342b. The piston rod 23 is made of wear-resistant elastic material. When the hydraulic system or the compression spring 7 suddenly fails, the piston rod 23, wheel frame 4, connecting shaft 5 and balance wheel 6 are mechanically limited with low impact force, avoiding damage to components, extending the service life of the overall structure, and also avoiding the possibility of the vehicle body 8 tilting or even overturning due to the sudden failure of a single hydraulic cylinder 22 or solenoid valve 21 when the three-way forklift is performing heavy-duty operations such as stacking. This greatly improves the safety performance of the balance wheel 6 connection structure during use.

[0035] See Figures 2-5 Optionally, a second groove 352 is provided on the circumferential surface of the piston rod 23, and a snap ring 353 nested in the second groove 352 is fixedly connected to the inner side of the mating part 35.

[0036] In this embodiment, the embedded engagement of the snap ring 353 and the second snap groove 352 achieves a rigid connection between the mating part 35 and the piston rod 23 without relative movement.

[0037] See Figures 2-5 Optionally, a limiting cavity 322 is provided inside the fixed sleeve 32, and the connecting block 33 and the irregular part 342 are both located inside the limiting cavity 322.

[0038] In this embodiment, the limiting cavity 322 of the fixed sleeve 32 constrains the radial displacement of the irregular part 342, ensuring that the first inclined surface 342a provided on the irregular part 342 is in a working position that can be accessed.

[0039] See Figure 2 Optionally, a connector 41 is installed on the wheel frame 4, and one end of the piston rod 23 is fixedly sleeved in the connector 41. A retaining ring 42 is embedded in the end of the piston rod 23, and the retaining ring 42 protrudes from the radial outer surface of the piston rod 23 to prevent the wheel frame 4 from falling off.

[0040] See Figures 1-9 An embodiment of the present invention provides a three-way forklift, including any of the balance wheel stabilization structures described above, comprising: a vehicle body 8, which includes a drive wheel 81 disposed at the bottom front side of the vehicle body 8, and two symmetrically distributed load-bearing wheels 82 disposed at the bottom rear side of the vehicle body 8; the balance wheel stabilization structure comprises two mutually symmetrical ones, which are respectively disposed on the left and right sides of the vehicle body 8 and respectively located on both sides of the drive wheel 81; and a frame 1 is connected to the vehicle body 8; wherein, the drive wheel 81, the two balance wheels 6, and the two load-bearing wheels 82 provide symmetrical five-point support for the vehicle body 8; and a solenoid valve 21 is electrically connected to the control system of the three-way forklift, and the opening and closing of the solenoid valve 21 is controlled by the control system of the three-way forklift.

[0041] In this embodiment, when the three-way forklift is running, the two balance wheel stabilizing structures symmetrically arranged on both sides of the vehicle body 8 can work independently under control. When traveling in a straight line or passing through uneven road surfaces, the control system can keep both balance wheels 6 in a floating state to buffer vibration. When performing operations that are prone to lateral shift of the center of gravity, such as lateral handling, turning, or high-level stacking, the control system can instruct one or both balance wheels 6 to switch to a locked state, so that they, together with the drive wheel 81 and the two rear load-bearing wheels 82, form a stable rigid support surface.

[0042] This three-way forklift increases the lateral support points of the vehicle by placing two stabilizing balance wheels on both sides of the drive wheel 81. When performing operations that easily cause lateral shift of the center of gravity, the locked balance wheel 6, together with the drive wheel 81 and the load-bearing wheel 82, forms a stable rigid support plane, fundamentally overcoming the deficiency of insufficient lateral support rigidity in the traditional four-point structure. At the same time, since the support state of the balance wheel 6 can be quickly switched by controlling the solenoid valve 21 to be energized and de-energized as needed, the vehicle does not need to rely on increasing the overall mass to obtain stability like the traditional three-point structure. This effectively solves the contradiction between lightweight and stability in the design of three-way forklifts. The five-point support structure design of this invention enables the three-way forklift to maintain flexibility and lightness under complex working conditions, while also having sufficient anti-tilt and anti-torsional deformation capabilities.

[0043] In the description of this invention, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A gyroscopically balanced wheel stabilizing structure, characterized by, Include: Frame (1), brake assembly (2), wheel frame (4), connecting shaft (5), balance wheel (6), compression spring (7) and limiting assembly (3); The brake assembly (2) is arranged on the side of the frame (1), the brake assembly (2) comprises an electromagnetic valve (21), a hydraulic cylinder (22) connected with the electromagnetic valve (21) and a piston rod (23) arranged in the hydraulic cylinder (22); The upper and lower cavities of the hydraulic cylinder (22) are communicated with the hydraulic source through the electromagnetic valve (21), the piston rod (23) is connected with the wheel frame (4) by extending out of the hydraulic cylinder (22), the balance wheel (6) is movably connected to the connecting shaft (5), the wheel frame (4) is connected with the connecting shaft (5), the compression spring (7) is arranged between the hydraulic cylinder (22) and the piston rod (23), and the limiting assembly (3) is connected between the frame (1) and the piston rod (23) to limit the stroke of the piston rod (23); Wherein, the electromagnetic valve (21) switches the locking state and floating state of the balance wheel (6) by switching the oil path of the hydraulic cylinder (22).

2. The wheel-stabilizing structure of claim 1, wherein The hydraulic cylinder (22) is internally provided with an annular groove (221), the piston rod (23) extends radially and has a protrusion (231), the compression spring (7) is sleeved on the piston rod (23), and the two ends of the compression spring (7) are connected with the inner wall of the groove (221) and the protrusion (231) respectively.

3. The wheel-stabilizing structure of claim 2, wherein, The limiting assembly (3) comprises a fixed seat (31) mounted on the frame (1) and connected with the shell of the hydraulic cylinder (22), a fixed sleeve (32) connected to the fixed seat (31), a connecting block (33) connected to the inner side of the fixed sleeve (32), a limiting piece (34) located in the inner side of the fixed sleeve (32) and a matching piece (35) arranged on one side of the piston rod (23) close to the wheel frame (4); The connecting block (33) is arranged in at least two and annularly distributed in the fixed sleeve (32), the side of the connecting block (33) facing the limiting piece (34) is provided with a first clamping groove (321), the limiting piece (34) is clamped in the first clamping groove (321), and the limiting piece (34) is used to abut against the matching piece (35) to limit the stroke of the piston rod (23).

4. The wheel-stabilizing structure of claim 3, wherein The limiting piece (34) comprises a connecting ring (341) clamped on the connecting block (33) and a special-shaped piece (342) axially fixedly connected to the connecting ring (341), the special-shaped piece (342) has a first inclined surface (342a), and the matching piece (35) has a second inclined surface (351) matched with the shape of the first inclined surface (342a).

5. The wheel-stabilizing structure of claim 4, wherein The connecting ring (341) and the special-shaped piece (342) are integrally formed and are made of wear-resistant elastic material.

6. The wheel-stabilizing structure of claim 5, wherein The special-shaped part (342) is provided with at least three and is annularly distributed around the central axis of the connecting ring (341), the special-shaped part (342) has a contact surface (342b) facing the piston rod (23), the shape of the contact surface (342b) is matched with the circumferential surface of the piston rod (23); When the second inclined surface (351) is in contact with the first inclined surface (342a), the contact surface (342b) is tightly attached to the circumferential surface of the piston rod (23).

7. The wheel-stabilizing structure of claim 6, wherein The circumferential surface of the piston rod (23) is provided with a second clamping groove (352), and the inner side of the fitting part (35) is fixedly connected with a clamping ring (353) embedded in the second clamping groove (352).

8. The wheel-stabilizing structure of claim 7, wherein, The fixed sleeve (32) is provided with a limiting cavity (322) inside, and the connecting block (33) and the special-shaped part (342) are located in the limiting cavity (322).

9. The wheel-stabilizing structure of claim 8, wherein, The wheel frame (4) is provided with a connecting piece (41), one end of the piston rod (23) is fixedly sleeved in the connecting piece (41), and a retaining ring (42) is embedded in the end of the piston rod (23), the retaining ring (42) protrudes from the radial outer surface of the piston rod (23) to prevent the wheel frame (4) from falling off.

10. A three-way fork truck comprising the balanced wheel stabilizing structure as claimed in any one of claims 1 to 9, characterized by, Comprise: The vehicle body (8) comprises a driving wheel (81) arranged at the bottom of the front side of the vehicle body (8), and two symmetrically distributed load wheels (82) arranged at the bottom of the rear side of the vehicle body (8); The balance wheel stabilizing structure is provided with two mutually symmetrical balance wheel stabilizing structures, and the two balance wheel stabilizing structures are respectively arranged on the left and right sides of the vehicle body (8) and are respectively located on the two sides of the driving wheel (81), and the vehicle frame (1) is connected to the vehicle body (8); Among them, the driving wheel (81), the two balance wheels (6) and the two load wheels (82) constitute a symmetrical five-point support for the vehicle body (8).

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