Method for improving stability of V-shaped thrust rod of heavy-duty automobile and V-shaped thrust rod

Abstract

The invention discloses a method for improving the stability of a V-shaped thrust rod of a heavy-load automobile and the V-shaped thrust rod. The V-shaped thrust rod is installed between an axle and a frame of the automobile. A main ball seat of the V-shaped thrust rod is vertically installed on an axle through a flange, two auxiliary ball hinges are installed on a vehicle frame in a hinged mode, and rod bodies of the two V-shaped thrust rods swing through the main ball seat and the auxiliary ball hinges. The axes of the two V-shaped thrust rod bodies extend and intersect together at the tip of the V-shaped thrust rod, and it is guaranteed that when the V-shaped thrust rod is installed on a truck, the extending intersection point of the axes of the two V-shaped thrust rod bodies and the rotation center of the ball head of the main ball seat are horizontally intersected at the same point position. The main ball seat ball core and the main ball seat ball head mandrel are in cylindrical transition fit, and the main ball seat ball core is fixed to the main ball seat ball head mandrel through a fastening bolt. The stability of the V-shaped thrust rod of the heavy-duty automobile is improved by controlling the spatial position deviation of the rotation center of the main ball seat ball head and the extension intersection of the axes of the two thrust rods and stably installing the main ball seat ball core and the main ball seat ball head mandrel.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a V-shaped thrust rod and a main ball joint in a heavy-duty truck, and more particularly to a method for improving the stability of the V-shaped thrust rod in a heavy-duty truck and the V-shaped thrust rod itself. This method for improving the stability of the V-shaped thrust rod in a heavy-duty truck and the V-shaped thrust rod itself can reduce the wear of the main ball joint of the thrust rod under heavy loads, effectively eliminate noise during operation, and improve the load-bearing capacity of the V-shaped thrust rod; it belongs to the field of heavy-duty truck suspension technology. Background Technology

[0002] Heavy-duty trucks generally use non-independent suspension, with leaf springs as their core component. However, leaf springs can only effectively transmit longitudinal forces (such as traction and braking forces) and lateral forces, but cannot effectively transmit the reaction torque generated by traction and braking forces. This makes it easy for heavy-duty trucks to sway when driving over bumpy roads, placing a huge load on the suspension system and severely affecting vehicle stability. The V-shaped thrust rod, as an independent connecting component, is hinged at one end to the frame and the other end to the axle, perfectly compensating for this deficiency. It reliably transmits these torques to the frame, ensuring that the axle moves synchronously with the vehicle body. Simultaneously, when the vehicle brakes or accelerates, the axle will sway back and forth due to inertia. The V-shaped thrust rod effectively limits this longitudinal displacement, preventing back-and-forth movement and avoiding axle "swaying," thus ensuring vehicle handling stability. Especially when the vehicle is turning, centrifugal force can cause lateral displacement of the middle and rear axles. The V-shaped triangular structure effectively resists this lateral swaying, preventing abnormal friction between the axle, leaf springs, and tires. If left unchecked, it can lead to abnormal tire wear, uneven wear, and even serious safety accidents such as tire blowouts.

[0003] Currently, there are many structural forms of V-type thrust rods in heavy-duty trucks. The mainstream type is a V-type thrust rod with a flange connection for the main ball joint, including a flanged main ball joint, a V-type thrust rod, and two auxiliary ball joints. The ball joint of the main ball joint is connected to the axle via a flange, and the main ball joint is installed perpendicular to the axle, serving as the main support point. In heavy-duty trucks, the stress distribution of this main ball joint structure is more balanced compared to the traditional cross-pin connection, further ensuring the stability of the V-type thrust rod connection. However, in actual operation, it has been found that existing flange-connected V-type thrust rods in heavy-duty trucks generally suffer from a lack of durability. This is mainly due to the various forces borne by the ball joint of the main ball joint of the V-type thrust rod in heavy-duty trucks. The force required is very large, and existing ball joints for main ball seats all use assembled ball heads, meaning the ball head and ball head seat are two separate parts. The ball head is fitted onto the spindle of the ball head seat and then secured with fasteners. However, existing fixing methods generally use either a tapered sleeve with bolts or a straight cylinder with a tight fit and elastic clips. Both of these assembly methods have some problems. Specifically, the tapered sleeve with bolts method involves making the inner hole of the ball head and the outer surface of the ball head spindle a matching tapered fit. The inner tapered hole of the ball head fits onto the outer tapered shaft of the ball head spindle, and then a screw is inserted from the bottom center through hole of the ball head spindle upwards and screwed directly into the screw hole of the ball head spindle, thus securing the ball head and the ball head spindle together. (See attached image) Figure 1 As shown; this fixing method offers some convenience for installation, as deviations can be adjusted using the taper between the ball head and the ball head spindle. However, it also makes it prone to loosening, especially in terms of horizontal position. This can cause the ball head of the thrust rod to move up and down during operation, severely affecting the stability of the V-shaped thrust rod. If the center of the ball head is not aligned with the axis of the thrust rod's pivot, the thrust rod can easily move up and down, eventually causing the ball head to slip off the ball head support spindle. Furthermore, the rotation center of the ball head is difficult to align with the height of the thrust rod and the ball head support, leading to localized high stress in one direction and affecting the overall stability of the V-shaped thrust rod. A straight-tube tight fit with elastic clamps, as shown in the attached diagram, provides a more stable solution. Figure 2As shown, this fixing method requires high precision in machining and assembly; otherwise, installation will be difficult and assembly will be challenging. Therefore, a transition fit is generally used for installation. After the ball core is installed on the ball head spindle, it is then fixed with bolts. However, current bolt fixing methods involve screwing the bolts into the threaded holes of the spindle from bottom to top. This locking method is not reliable enough, and the ball core is prone to slipping off the ball head spindle. Moreover, using elastic clamps to fix the ball head and ball head spindle makes it difficult to accurately determine the axial dimension. The greater the deviation, the more likely the ball head will move up and down relative to the ball head spindle under the huge load of a heavy-duty truck. Especially when the elastic clamps pop out, the ball head is prone to flying off. Therefore, current heavy-duty V-type thrust rods are considering adding an anti-dislodgement mechanism to the main ball seat. Therefore, how to improve the stability of heavy-duty V-type thrust rods is worthy of in-depth research.

[0004] The search did not find any identical technical reports, only technical literature in related fields. The most similar ones are as follows: 1. Patent document with publication number DE102004029581B4 discloses a center joint for an A-arm of a motor vehicle (especially a commercial vehicle). The center joint includes a ball head and a ball head seat. The ball head is composed of a ball head sleeve and a ball core. The ball head seat is composed of a flange seat and a ball head seat spindle. The ball core is sleeved on the ball head seat spindle and is fastened by bolts passing through the ball head seat spindle from the bottom to form a fixed structure. The ball head sleeve wraps around the ball core to form a ball hinge structure. The ball head sleeve is installed outside the center joint housing to form a rotatable and swingable cross arm center joint. Although this center joint has a basic structure similar to the main ball seat of the V-type thrust rod, the patent does not focus on the position of the ball joint center. Moreover, the fixing method and structure of its ball core sleeve and ball head seat spindle are complicated. The fastening bolt passes through the ball head seat spindle from the bottom and pulls a conical ball core sleeve nut from the bottom. In order to ensure the thread length of the locking force and not increase the height of the housing, a conical boss must be formed inside the ball head seat spindle. However, this makes it difficult to accurately position the center of the ball head. Therefore, it is not suitable for a structure that accurately positions the rotation center of the ball head of the V-type thrust rod main ball seat, and thus cannot solve the problems mentioned above.

[0005] 2. Patent document CN101061000A discloses a universal joint unit for a guide rod of a wheel suspension device in a motor vehicle. This unit has a housing and a journal, the journal being slidably mounted in the housing via a spherical support surface. The universal joint unit has a limiting device to prevent complete separation of the housing from the journal. This limiting device crosses a portion of the housing without contact during normal operation. Furthermore, the limiting device has at least one flexible limiting band or at least one safety clamp with a notch, or at least two safety clamps, in which the housing's limiting pin is inserted without contact during normal operation. This patent uses a clamp-type limiting ball core structure, which naturally suffers from the aforementioned problem of clamp slippage. Moreover, this patent does not address how to ensure the ball joint's rotation center position, also resulting in ball joint instability. Therefore, further improvements are needed.

[0006] 3. Patent document CN111032376A discloses a central joint for a three-point linkage. The central joint has a housing that is rotatable and swing-supported relative to the central joint's shaft connection via a ball-and-socket joint. The patent emphasizes that the central joint also has an anti-disengagement mechanism that acts as a stop. This anti-disengagement mechanism extends perpendicular to the central axis of the shaft connection and prevents separation of the housing and shaft connection in the event of ball-and-socket joint failure. The anti-disengagement mechanism effectively extends perpendicular to the central axis of the shaft connection in two spatial directions. It also emphasizes that the internal components are solid or annular and have a convex outer surface, which is a ball-and-socket joint. Preferably, the ball-and-socket joint extends at least substantially symmetrically with respect to the equator of the internal components. However, this patent does not address the position of the ball joint center or consider its impact on the stability of the entire thrust rod. In particular, the ball core lacks vertical constraint, making it prone to vertical movement, which affects the stability of the thrust rod. Therefore, further improvements are needed.

[0007] In summary, existing technologies have not carefully considered how to improve the stability of V-shaped thrust rods by accurately determining the center position of the ball joint, thereby reducing the vertical movement of the main ball joint head and improving the overall performance of the V-shaped thrust rod. Therefore, further research and improvement are still needed. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the shortcomings of existing flange connection V-type thrust rod main ball seat, which is prone to vertical movement of the ball core, resulting in wear and even detachment. The present invention provides a method to improve the stability of the V-type thrust rod main ball seat for heavy-duty vehicles, effectively prevent vertical movement of the ball core, and avoid the ball core from detaching. Another objective of this invention is to provide a heavy-duty vehicle V-type thrust rod manufactured using the above-described method for improving the stability of the main ball seat of the V-type thrust rod in heavy-duty vehicles, effectively preventing the ball core from moving up and down and avoiding the ball core from coming out.

[0009] This invention is mainly achieved through the following technical solution: a method for improving the stability of a V-shaped thrust rod in a heavy-duty truck, wherein the V-shaped thrust rod is installed as an independent connecting component between the vehicle's axle and frame; wherein the main ball joint of the V-shaped thrust rod is vertically mounted on the axle via a flange, and two auxiliary ball joints are respectively hinged to the frame; the two V-shaped thrust rods allow for adaptive oscillation via the main ball joint and auxiliary ball joints; its characteristic is that the axes of the two V-shaped thrust rods converge at the tip of the V-shaped thrust rod, ensuring that when the V-shaped thrust rod is installed on the truck, The intersection point of the extended axes of the two V-shaped thrust rods is horizontally aligned with the rotation center of the main ball joint. Simultaneously, the main ball joint core and the main ball joint spindle utilize a cylindrical transition fit, and the main ball joint core is fixed to the main ball joint spindle from above using fastening bolts. By controlling the spatial positional deviation between the rotation center of the main ball joint and the intersection point of the extended axes of the two thrust rods, and by ensuring the stable installation of the main ball joint core and the main ball joint spindle, the tendency for vertical displacement of the main ball joint center during operation is reduced, thereby improving the stability of the V-shaped thrust rod for heavy-duty vehicles.

[0010] The reason for emphasizing that the axes of the two V-shaped thrust rods converge at the tip of the V-shaped thrust rod, and ensuring that the point of convergence of the axes of the two V-shaped thrust rods coincides horizontally with the center of rotation of the main ball joint when the V-shaped thrust rod is installed on the truck, is because the inventors, through analysis and research on the phenomenon that the main ball joint of the V-shaped thrust rod easily slips off the ball joint spindle, discovered that this slippage is mainly due to the fact that during the operation of the V-shaped thrust rod, the two V-shaped thrust rods swing up and down with the main ball joint and the auxiliary ball joint. Theoretically, if the point of convergence of the axes of the two V-shaped thrust rods coincides horizontally with the center of rotation of the main ball joint, the V-shaped thrust rods should only rotate around the center of rotation of the main ball joint during operation. However, due to… Because perfect concentricity is difficult to achieve, during the operation of a V-shaped thrust rod, the rod body not only rotates around the ball head's rotation center, but also experiences eccentric torque due to the fact that the intersection point of the V-shaped thrust rod's axis extensions is not at the same horizontal point as the ball head's rotation center, and the axis extensions of the thrust rod body do not converge at the tip of the V-shaped thrust rod. This eccentric torque causes the ball head of the ball seat to not only rotate around the rotation center during the operation of the V-shaped thrust rod, but also to deviate vertically and horizontally. When this vertical and horizontal deviation reaches a certain extent, it can cause the ball head of the ball seat to loosen or even slip off. This is the fundamental reason why an anti-slip device or mechanism is needed on the ball head spindle of the ball seat to prevent the ball head from slipping off, especially after the addition of an inclined design between the ball head sleeve and the thrust rod in modern V-shaped thrust rods (as shown in the attached figure). Figure 2 As shown in the figure, this makes it easier for the center of the ball joint to deviate from the center of convergence of the thrust rod axis, thereby increasing the possibility of vertical movement during operation. Therefore, by effectively controlling the spatial position deviation between the rotation center of the main ball joint and the extended intersection point of the axes of the two thrust rods, the vertical displacement tendency of the main ball joint center during operation can be reduced, and the stability of the V-type thrust rod of heavy-duty truck can be improved by reducing the vertical displacement tendency of the main ball joint.

[0011] On the other hand, during the research and development process, the inventors discovered that the installation of the main ball seat core and the ball head spindle is also crucial for ensuring the stability of the main ball seat and preventing vertical movement. Previous main ball seats were typically secured with a single bolt from bottom to top, or had anti-detachment devices added to the ball head spindle to prevent the core from slipping out. However, these methods were ineffective and inconvenient to install. Therefore, they proposed a transition fit installation between the main ball seat core and the ball head spindle, secured by a single bolt from top to bottom. This makes the connection between the main ball seat core and the ball head spindle extremely secure. This transition fit, combined with the top fastening structure, not only significantly improves axial resistance to movement but also ensures more even stress distribution and precise assembly of the core. Real-world road tests have shown that under a full load of 120 tons and continuous operation for 5000 kilometers, the main ball seat showed no loosening or slippage, and radial displacement was controlled within ±0.08mm, representing a 63% improvement in stability compared to traditional structures.

[0012] Furthermore, the spatial position deviation of the intersection point between the main ball joint's rotation center and the extended axes of the two thrust rods is controlled to be ≤0.65mm. This spatial position deviation refers to the spatial position deviation of the intersection point of the two thrust rod axes around the main ball joint's rotation center. It includes the three-dimensional spatial position deviation of the sphere centered on the main ball joint's rotation center in terms of vertical, horizontal, and front-back directions, ensuring that when the main ball joint sleeve and the main ball joint spindle are assembled together, the intersection point of the main ball joint's rotation center and the two thrust rod axes is as close as possible.

[0013] Through repeated research, it was found that effectively controlling the spatial positional deviation of the intersection point of the main ball joint's rotation center and the extended axes of the two thrust rods can reduce the vertical displacement tendency of the main ball joint's rotation center during operation. This requires finding a suitable balance point, that is, minimizing the spatial positional deviation of the intersection point of the main ball joint's rotation center and the extended axes of the two thrust rods, while also considering the feasibility of actual manufacturing capabilities. Through testing of various implementation schemes, it was confirmed that controlling the spatial offset of the intersection point of the main ball joint's rotation center point and the axes of the two thrust rods, as well as the intersection point of the main ball joint's rotation center point and the axis of the ball joint spindle, to ≤0.65mm is the most feasible limiting technical solution.

[0014] This offset control range ensures that the machining accuracy meets the requirements for reducing eccentric torque and lowering the probability of axial movement, without significantly increasing production costs due to excessively high precision requirements, thus meeting the actual needs of mass production of heavy-duty truck parts. If the offset exceeds 0.65mm, the additional axial force generated by the eccentric torque will exceed the locking limit of the existing fasteners, causing loosening between the ball head and the spindle in a short time, leading to axial wear and significantly shortening the service life of the V-type thrust rod.

[0015] Furthermore, controlling the spatial position deviation of the main ball seat ball head rotation center point and the intersection point of the two thrust rod shaft axes to ≤0.65mm includes controlling the spatial position deviation of the intersection point of the main ball seat shell inner hole axis and the two thrust rod shaft axes, as well as the spatial position deviation of the center of the spherical surface of the main ball seat ball head sleeve inner hole and the axis of the main ball seat shell inner hole; the spatial position deviations of both are controlled to ≤0.30mm, ensuring that when the main ball seat ball head sleeve and the main ball seat ball core are assembled together, the spatial position offset of the main ball seat ball head rotation center point and the intersection point of the two thrust rod shaft axes coinciding with each other is controlled to ≤0.65mm.

[0016] This dual-precision control strategy is based on the fact that the intersection of the main ball joint's rotation center point and the axes of the two thrust rods is mainly located by the inner hole axis of the outer shell to form the thrust rod intersection reference. Then, the rotation origin of the main ball joint's rotation center point is calibrated by the position of the center of the spherical surface of the inner hole of the main ball joint sleeve. The two work together to compress the accumulated error, so that the intersection of the ball joint's rotation center point and the axes of the two thrust rods is controlled within the determined spatial position deviation range.

[0017] Furthermore, the spatial position deviation between the rotation center point of the main ball bearing and the intersection point of the axes of the two thrust rods is achieved by controlling the consistency between the machining accuracy of the inner hole of the main ball bearing shell and the assembly positioning reference. Specifically, a high-precision coordinate measuring machine is used to verify the spatial position of the inner hole axis in real time, and a laser tracker is used to dynamically monitor the intersection point of the thrust rod axes to ensure that the spatial deviation between the two is 0.65mm. At the same time, the deviation between the center of the spherical surface of the inner hole of the main ball bearing and the axis of the inner hole of the shell is controlled by ultra-precision grinding process and online contour detection closed-loop compensation, so that the single machining form and position error is stably suppressed within ±0.30mm.

[0018] Furthermore, the aforementioned control of the spatial position deviation between the main ball joint's rotation center and the main ball joint's spindle axis also includes the machining and installation accuracy of the ball joint sleeve and the inner hole of the main ball joint housing, as well as the horizontal and vertical deviations between the main ball joint's rotation center and the main ball joint's spindle axis, both of which must be controlled within ≤0.30mm; ensuring that when the main ball joint sleeve and the main ball joint's core are assembled together, the offset of the main ball joint's rotation center coinciding with the intersection point of the axes of the two thrust rods is controlled within ≤0.65mm.

[0019] Furthermore, the secure installation of the main ball seat core and the main ball seat mandrel includes assembling the main ball seat core and the main ball seat mandrel together through a cylindrical transition fit, and strictly controlling the coaxiality and interference tolerance of the ball head mandrel and the ball head mandrel mounting hole, while controlling the spatial position deviation between the center of the outer spherical surface of the main ball seat core and the axis of the main ball seat mandrel to be ≤0.30mm.

[0020] The coaxiality and interference tolerance of the control ball head mandrel and the ball head mandrel mounting hole are achieved by using a hot fitting process combined with real-time force-displacement closed-loop monitoring by a servo press fitting machine. After assembly, a dual-frequency laser interferometer is used to detect the spatial position deviation of the center of the outer spherical surface of the main ball seat ball core relative to the axis of the main ball seat mandrel, ensuring that the radial and axial runout of the main ball seat ball core relative to the mandrel axis is ≤0.30mm after assembly.

[0021] Furthermore, the secure installation of the main ball seat core and the main ball seat head spindle also includes fixing the main ball seat core to the main ball seat head spindle from above using fastening bolts; after the main ball seat core is fitted onto the main ball seat head spindle through the inner hole of the core with an transition fit, the bottom surface of the inner hole step of the core is tightly attached to the upper step surface of the spindle, and then the fastening bolt passes through the center hole of the main ball seat core from above and extends into the threaded hole of the main ball seat head spindle near the flange mounting surface of the main ball seat, further locking and fixing the main ball seat core together to prevent loosening between the main ball seat core and the main ball seat head spindle.

[0022] The reason for tightening the bolts again after the main ball bearing core is fitted onto the main ball bearing head spindle via an intermediate fit through the core's inner hole is to prevent spatial misalignment between the main ball bearing head's rotation center point and the intersection of the two thrust rod axes. If the main ball bearing core and the main ball bearing head spindle become loose, the spatial position of the main ball bearing head's rotation center point will deviate from the intersection of the two thrust rod axes. This will affect the force acting on the thrust rod as it swings around the main ball bearing head's rotation center point, creating a prying force that loosens the main ball bearing core and the main ball bearing head spindle. Therefore, ensuring a stable fit between the main ball bearing core and the main ball bearing head spindle is crucial.

[0023] Furthermore, the threaded hole is located at one end of the main ball seat core near the main ball seat flange mounting surface through the inner hole of the core, and ensures that the thread engagement length between the threaded hole and the fastening bolt is greater than 20mm; moreover, the bottom surface of the bolt nut adopts a toothed texture structure to further increase the friction of the bolt and fully ensure the bolt's locking force.

[0024] Furthermore, the main ball seat core is fitted onto the ball head spindle via an transition fit, and is pressed and fixed from the main ball seat core by a clamping bolt, ensuring that the height of the bottom surface of the inner hole of the main ball seat core and the mounting surface of the main ball seat flange is such that the rotation center point of the main ball seat ball head is located at the horizontal position of the axis of the two thrust rods arranged in a "V" shape.

[0025] This invention also relates to a V-shaped thrust rod for heavy-duty vehicles manufactured according to the aforementioned method for improving the stability of V-shaped thrust rods in heavy-duty vehicles. The rod includes a main ball seat, a thrust rod body, and auxiliary ball joints. There are two thrust rod bodies arranged in a "V" shape, with one end connected together and the other ends separated to form a "V" shape. An auxiliary ball joint is installed at the separated end of each of the two thrust rod bodies. The outer shell of the main ball seat is connected to the end where the two thrust rod bodies are connected in the "V" shape. The key feature is that the intersection point of the axes of the two "V"-shaped thrust rod bodies overlaps with the rotation center of the ball head of the main ball seat, and the spatial offset between the intersection point of the thrust rod body axes and the rotation center of the ball head of the main ball seat is controlled to be ≤0.65mm.

[0026] Furthermore, the main ball seat includes a main ball seat head sleeve, a main ball seat core, a main ball seat head shell, and a main ball seat head spindle. The main ball seat head sleeve is installed inside the inner hole of the main ball seat head shell, and the axis of the inner hole of the shell intersects the axis of the main ball seat head spindle at an angle of less than 15 degrees. The bottom of the main ball seat head sleeve is limited by the bottom surface of the stepped inner hole of the main ball seat head shell, and the upper part is axially limited by a clamp. The main ball seat core and the main ball seat head... The mandrel adopts a cylindrical transition fit. The main ball seat core is fitted onto the main ball seat head mandrel through the transition fit of the inner hole of the core, and is locked and fixed from the upper surface of the main ball seat core downward by fastening bolts. The main ball seat head sleeve wraps around the outer spherical surface of the main ball seat core, forming a ball head pair. The rotation center of the ball head pair overlaps with the intersection point of the extension of the axes of the two thrust rods. After the V-shaped thrust rod is installed on the frame, the axes of the two thrust rods are in a horizontal state.

[0027] Furthermore, the overlap between the ball head rotation center of the ball head assembly and the extended intersection point of the axes of the two thrust rods is to constrain the spatial distance (H) from the bottom surface of the inner hole step of the main ball head shell to the extended intersection point of the central axes of the two thrust rods, and the spatial distance (H) between the center of the main ball head sleeve 5 and the lower end face 23 of the main ball head sleeve, so that when the main ball head sleeve is obliquely installed into the inner hole of the main ball head shell, the rotation center of the inner spherical surface of the main ball head sleeve overlaps with the extended intersection point of the axes of the two thrust rods.

[0028] Furthermore, the fastening bolt is locked and fixed downwards from the upper surface of the main ball seat core. A threaded through hole is provided at the center of the main ball seat ball head mandrel, with the threaded portion located at one end near the main ball seat flange mounting surface. The main ball seat core has a two-stage stepped inner hole at its center. The first stage inner hole is the central hole of the main ball seat core through which the fastening bolt passes, and the second stage inner hole is the main ball seat core inner hole that mates with the ball head mandrel. The main ball seat core is then installed onto the main ball seat ball seat via an transition fit. After the head spindle is in place, the bottom surface of the inner hole of the main ball seat core contacts the upper step surface of the main ball seat head spindle. The fastening bolt is a locking screw with a toothed plane on the lower end face of the bolt head. When the inner plane of the main ball seat core contacts the upper surface of the main ball seat head spindle, the screw part of the fastening bolt passes through the center hole of the main ball seat core and is screwed onto the threaded hole of the main ball seat head spindle for locking and positioning, ensuring that the axes of the two thrust rods are in a horizontal state.

[0029] Furthermore, the horizontal orientation of the two thrust rods constrains the height of the upper surface of the main ball bearing mandrel and the depth of the inner hole of the main ball bearing mandrel. This ensures that when the main ball bearing mandrel is installed onto the main ball bearing mandrel via an adapter fit, the upper surface of the main ball bearing mandrel contacts the inner plane of the inner hole of the main ball bearing mandrel. The mandrel is then secured from above with fastening bolts, ensuring that the axes of the two thrust rods are horizontal after the V-shaped thrust rod is installed on the frame.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: by precisely controlling the positional deviation of the main ball seat core rotation center and the intersection point of the axes of the two thrust rods and the axis of the ball head spindle, the eccentric torque generated during the operation of the V-shaped thrust rod is reduced from the root, thus reducing the external force source of axial movement of the core; at the same time, in conjunction with the upper and lower bidirectional axial positioning structure of the core and the fastening bolt design that goes in from top to bottom, the axial displacement of the core and the loosening of the bolts are further avoided. The dual protection greatly improves the overall stability and service life of the V-shaped thrust rod, and reduces the probability of safety accidents caused by the failure of the V-shaped thrust rod in heavy-duty trucks.

[0031] This invention, through strict control of the positional tolerances of key components, ensures that the coordinated control of all geometric tolerances ultimately aims at a core objective: achieving sub-micron-level coincidence between the rotation center of the main ball joint and the intersection point of the axes of the two thrust rods in three-dimensional space. This precision relies not only on breakthroughs in single-process technology limits but also on the high degree of unification of design, manufacturing, and testing standards. Actual measurement data shows that in 100 consecutive assembly samples, the maximum coincidence offset was 0.647 mm, with a standard deviation of only 0.158 mm, verifying the robustness and reproducibility of this technical approach. Furthermore, this series of stringent tolerance controls and assembly processes significantly improves the service life of the V-type thrust rod under heavy load and high-frequency vibration conditions. In actual vehicle testing, it reduces the abnormal wear rate of the ball core by 72%, bringing the risk of disengagement close to zero. By controlling the positional offset (H) of the distance between the intersection point of the thrust rod's axis and the axis of the main ball joint's ball head sleeve to ≤0.65mm, the fretting wear of the ball core can be effectively suppressed, significantly extending the service life of the ball joint. Combined with precision assembly tolerance control, the main ball joint maintains stable axial constraint stiffness within a wide temperature range of -40℃ to 120℃, and the measured maximum ball core movement is reduced to within 0.18mm, improving stability by 62% compared to traditional structures. This technological breakthrough not only solves industry pain points such as easy loosening, abnormal noise, and early failure of ball joints under heavy load conditions, but also upgrades assembly precision control from experience-based control to effective dimensional precision control through multi-dimensional collaborative tolerance allocation.

[0032] Under long-term vehicle vibration and heavy load impact, the V-shaped thrust rod structure, after nearly 3 months of real vehicle road test data, showed that in a continuous 5000km full-load rough road test, the V-shaped thrust rod did not show any abnormal wear of the ball joint or excessive axial displacement, verifying the engineering reliability and mass production consistency of the design under extreme working conditions. Attached Figure Description

[0033] Figure 1 A schematic diagram of the overall structure of the existing conical main ball seat mandrel V-type thrust rod; Figure 2 A schematic diagram of the overall structure of the existing cylindrical main ball seat mandrel V-shaped thrust rod; Figure 3 This is a schematic diagram of the overall structure of the V-shaped thrust rod of the present invention; Figure 4 for Figure 3 A top-view structural diagram; Figure 5 This is a schematic diagram of the main ball seat structure of the present invention; Figure 6 This is a schematic diagram of the main ball seat ball head sleeve structure of the present invention; Figure 7 This is a schematic diagram of the main ball seat core structure of the present invention.

[0034] Explanation of reference numerals: 1. Main ball seat; 2. Thrust rod body; 3. Secondary ball hinge; 4. Main ball seat ball head shell; 5. Main ball seat ball head sleeve; 6. Main ball seat ball core; 7. Main ball seat ball head spindle; 8. Inner bore axis of the shell; 9. Main ball seat spindle axis; 10. Central axis; 11. Fastening bolt; 12. Intersection of the rod body axes; 13. Ball head rotation center; 14. Upper stepped surface of the spindle; 15. Inner bore of the shell; 16. Stepped surface of the inner bore of the shell; 17. Clamp; 18. Inner bore of the ball core; 19. Bottom surface of the stepped inner bore of the ball core; 20. Main ball seat flange mounting surface; 21. Center hole of the main ball seat ball core; 22. Threaded hole; 23. Lower end face of the main ball seat ball head sleeve; 24. Inner bore of the main ball seat ball core. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Example 1

[0036] This embodiment is a V-shaped thrust rod for heavy-duty vehicles, including a main ball seat 1, a thrust rod body 2, and an auxiliary ball joint 3. There are two thrust rod bodies 2, arranged in a "V" shape. One end of the two thrust rod bodies 2 is connected together, and the other end is separated to form a "V" shape. An auxiliary ball joint 3 is installed at the separated end of each of the two "V" shaped thrust rod bodies 2. The main ball seat shell 4 of the main ball seat 1 is connected to the end where the two thrust rod bodies 2 are connected together. The key feature is that the central axis 10 of the two thrust rod bodies 2 extends to the intersection point 12 of the rod axis and overlaps with the ball head rotation center 13 of the main ball seat 1. The spatial offset of the overlap between the central axis 10 of the two thrust rod bodies 2 extending to the intersection point 12 of the rod axis and the ball head rotation center 13 of the main ball seat is controlled to be ≤0.65mm.

[0037] Furthermore, the main ball seat 1 includes a main ball seat head sleeve 5, a main ball seat core 6, a main ball seat head housing 4, and a main ball seat head spindle 7. The main ball seat head sleeve 5 is installed inside the inner hole 15 of the main ball seat head housing 4, and the axis 8 of the inner hole 15 intersects the axis 9 of the main ball seat spindle at an angle α less than 15 degrees. The bottom of the main ball seat head sleeve 5 is limited by the stepped surface 16 of the inner hole of the main ball seat head housing 4, and the upper part is axially limited by a clamp 17. The main ball seat core 6 and the main ball seat ball... The head spindle 7 adopts a cylindrical transition fit. The main ball seat core 6 is fitted onto the main ball seat head spindle 7 through the inner hole 18 of the core, and is locked and fixed from the upper surface of the main ball seat core 6 downward by the fastening bolt 11. The main ball seat head sleeve 5 wraps around the outer spherical surface of the main ball seat core 6 to form a ball head pair. The ball head rotation center 13 overlaps with the intersection point 12 of the axis extension of the two thrust rods 2. After the V-shaped thrust rod is installed on the frame, the central axis 10 of the two thrust rods 2 is in a horizontal state.

[0038] Furthermore, the overlap of the ball head rotation center 13 of the ball head assembly with the extension intersection point 12 of the axes of the two thrust rods 2 constrains the spatial distance (H) between the inner bore step surface 16 of the main ball head shell 4 and the extension intersection point 12 of the central axis 10 of the two thrust rods 2, as well as the spatial distance (H) between the center of the main ball head sleeve 5 and the lower end face 23 of the main ball head sleeve. This ensures that when the main ball head sleeve 5 is obliquely installed inside the inner bore 15 of the main ball head shell 4, the rotation center 13 of the inner spherical surface of the main ball head sleeve 5 overlaps with the extension intersection point 12 of the axes of the two thrust rods 2.

[0039] Furthermore, the fastening bolt 11 is locked and fixed from the upper surface of the main ball seat core 6 downwards: a threaded hole 22 is provided at the center of the main ball seat ball head spindle 7, and the threaded hole 22 is located at one end near the main ball seat flange mounting surface 20 of the main ball seat 1. The main ball seat core 6 has a core inner hole 18 at its center. The core inner hole 18 is a two-stage stepped inner hole. The first stage inner hole is the main ball seat core center hole 21 that passes through the fastening bolt 11, and the second stage inner hole is the main ball seat core inner hole 24 that matches the ball head spindle. After the main ball seat core 6 is installed on the main ball seat ball head spindle 7 through an transition fit, the bottom surface 19 of the core inner hole 24 of the main ball seat core contacts the upper stepped surface 14 of the spindle of the main ball seat ball head spindle 7. The fastening bolt 11 is a locking screw with a toothed plane at the lower end of the bolt head. When the inner plane of the core inner hole of the main ball seat contacts the upper surface of the main ball seat ball head spindle 7, the screw part of the fastening bolt 11 passes through the core inner hole 21 of the main ball seat core 6 and is screwed into the threaded hole 22 of the main ball seat ball head spindle 7 for locking and positioning, ensuring that the axes of the two thrust rods 2 are in a horizontal state.

[0040] Furthermore, the horizontal orientation of the axes of the two thrust rods 2 constrains the height of the stepped surface 14 on the spindle of the main ball bearing mandrel 7 and the depth of the inner hole 24 of the main ball bearing mandrel. This ensures that when the main ball bearing mandrel 6 is installed onto the main ball bearing mandrel 7 via an transition fit, the bottom surface 19 of the stepped surface of the inner hole of the main ball bearing mandrel 7 contacts the inner plane of the inner hole 24 of the main ball bearing mandrel. The mandrel is then secured from above by fastening bolts 11, ensuring that the axes of the two thrust rods 2 are horizontal after the V-shaped thrust rod is installed on the frame. Example 2

[0041] The basic principle of this embodiment is the same as that of Embodiment 1. The difference is that when the V-shaped thrust rod adopts an open-type main ball seat structure, the positioning and assembly method of this invention is also applicable. Specifically, the main ball seat shell of the open-type main ball seat is divided into upper and lower split structures. During assembly, the main ball seat ball head sleeve is first pre-installed into the inner hole of the lower half of the shell. Then, the position of the rotation center of the inner spherical surface of the main ball seat ball head sleeve is calibrated by a high-precision positioning fixture to ensure that the spatial offset of the intersection point of the extension of the axes of the two thrust rods is controlled within ≤0.65mm. After that, the upper half of the shell is closed to complete the fixation. Finally, the main ball seat ball core is installed on the main ball seat ball head spindle through a cylindrical transition fit in the manner of locking from the top, and is locked and fixed from top to bottom with fastening bolts. Tests showed that, under this structure, the radial displacement of the main ball seat can also be controlled within ±0.65mm after adopting the method of the present invention. The long-term operational stability is improved by 58% compared with the traditional open-type V-shaped thrust rod, indicating that the method of the present invention is applicable to V-shaped thrust rods with different structural forms and has strong versatility.

[0042] As can be seen from the above embodiments, the present invention also relates to a method for improving the stability of a V-shaped thrust rod in a heavy-duty truck. The V-shaped thrust rod is installed as an independent connecting component between the vehicle's axle and frame. The main ball joint of the V-shaped thrust rod is vertically mounted on the axle via a flange, and two auxiliary ball joints are respectively hinged to the frame. The two V-shaped thrust rods oscillate adaptively through the main ball joint and the auxiliary ball joints. The key feature is that the axes of the two V-shaped thrust rods converge at the tips of the V-shaped thrust rods, ensuring that when the V-shaped thrust rod is installed on the truck, the two... The intersection point of the extended axes of the V-shaped thrust rod body and the center of rotation of the main ball joint are horizontally intersected at the same point. At the same time, the main ball joint core and the main ball joint spindle 7 adopt a cylindrical transition fit, and the main ball joint core is fixed to the main ball joint spindle 7 from above by fastening bolts. By controlling the spatial position deviation between the center of rotation of the main ball joint and the intersection point of the extended axes of the two thrust rods, and by achieving a stable installation of the main ball joint core and the main ball joint spindle 7, the vertical displacement tendency of the center of rotation of the main ball joint during operation is reduced, thereby improving the stability of the V-shaped thrust rod for heavy-duty vehicles.

[0043] The reason for emphasizing that the axes of the two V-shaped thrust rods converge at the tip of the V-shaped thrust rod, and ensuring that the point of convergence of the axes of the two V-shaped thrust rods is horizontally aligned with the rotation center of the main ball joint when the V-shaped thrust rod is installed on the truck, is because the inventors analyzed the phenomenon that the main ball joint of the V-shaped thrust rod easily slips off the ball joint spindle. They discovered that this phenomenon is mainly because during the operation of the V-shaped thrust rod, the two V-shaped thrust rods swing up and down with the main ball joint and the auxiliary ball joint. Theoretically, if the point of convergence of the axes of the two V-shaped thrust rods is horizontally aligned with the rotation center of the main ball joint, the V-shaped thrust rods should only rotate around the rotation center of the main ball joint during operation. However, due to the difficulty in achieving perfect concentricity, during the operation of the V-shaped thrust rod, the rod body not only rotates around the ball head's rotation center, but also experiences eccentric torque because the intersection point of the extended axes of the V-shaped thrust rod and the horizontal intersection point of the main ball seat's ball head's rotation center are not at the same location, and the axes of the thrust rod body do not intersect at the tip of the V-shaped thrust rod. This eccentric torque causes the main ball seat's ball head to not only rotate around the rotation center during the operation of the V-shaped thrust rod, but also to experience vertical and horizontal offset. When this offset reaches a certain level, it can cause the main ball seat's ball head to loosen or even slip off. This is the fundamental reason why an anti-slip device or mechanism is needed on the main ball seat's ball head spindle to prevent the ball head from slipping off. This is especially true now that modern V-shaped thrust rods have an inclined design between the ball head sleeve and the thrust rod (as shown in the attached image). Figure 2 As shown in the diagram, this makes it easier for the center of the ball joint to deviate from the convergence center of the thrust rod axis, thus increasing the possibility of vertical movement during operation. Therefore, by effectively controlling the spatial positional deviation between the rotation center of the main ball joint and the extended intersection point of the two thrust rod axes, the vertical movement tendency of the main ball joint center during operation can be reduced, and the stability of the V-type thrust rod for heavy-duty vehicles can be improved by reducing the vertical movement tendency of the main ball joint.

[0044] On the other hand, during the research and development process, the inventors discovered that the installation of the main ball seat core and the ball head spindle is also crucial for ensuring the stability of the main ball seat and preventing vertical movement. Previous main ball seats were typically secured with a single bolt from bottom to top, or had anti-detachment devices added to the ball head spindle to prevent the core from slipping out. However, these methods were ineffective and inconvenient to install. Therefore, they proposed a transition fit installation between the main ball seat core and the ball head spindle, secured by a single bolt from top to bottom. This makes the connection between the main ball seat core and the ball head spindle extremely secure. This transition fit, combined with the top fastening structure, not only significantly improves axial resistance to movement but also ensures more even stress distribution and precise assembly of the core. Real-world road tests have shown that under a full load of 120 tons and continuous operation for 5000 kilometers, the main ball seat showed no loosening or slippage, and radial displacement was controlled within ±0.08mm, representing a 63% improvement in stability compared to traditional structures.

[0045] Furthermore, the spatial position deviation of the intersection point between the main ball joint's rotation center and the extended axes of the two thrust rods is controlled to be ≤0.65mm. This spatial position deviation refers to the spatial position deviation of the intersection point of the two thrust rod axes around the main ball joint's rotation center. It includes the three-dimensional spatial position deviation of the sphere centered on the main ball joint's rotation center in terms of vertical, horizontal, and front-back directions, ensuring that when the main ball joint sleeve and the main ball joint spindle are assembled together, the intersection point of the main ball joint's rotation center and the two thrust rod axes is as close as possible.

[0046] Through repeated research, it was found that to effectively control the spatial positional deviation of the intersection point of the main ball joint's rotation center and the extended axes of the two thrust rods, the vertical displacement tendency of the main ball joint's rotation center during operation can be reduced. This requires finding a suitable balance point: minimizing the spatial positional deviation of the intersection point of the main ball joint's rotation center and the extended axes of the two thrust rods, while also considering actual manufacturing capabilities. Through testing of various implementation schemes, it was confirmed that controlling the spatial positional offset of the intersection point of the main ball joint's rotation center with the axes of the two thrust rods, and the intersection point of the main ball joint's rotation center with the axis of the ball joint spindle, to ≤0.65mm is the most feasible and limited technical solution.

[0047] This offset control range ensures that the machining accuracy meets the requirements for reducing eccentric torque and lowering the probability of axial movement, without significantly increasing production costs due to excessively high precision requirements, thus meeting the actual needs of mass production of heavy-duty truck parts. If the offset exceeds 0.65mm, the additional axial force generated by the eccentric torque will exceed the locking limit of the existing fasteners, causing loosening between the ball head and the spindle in a short time, leading to axial wear and significantly shortening the service life of the V-type thrust rod.

[0048] Furthermore, controlling the spatial position deviation of the main ball seat ball head rotation center point and the intersection point of the two thrust rod shaft axes to ≤0.65mm includes controlling the spatial position deviation of the intersection point of the main ball seat shell inner hole axis and the two thrust rod shaft axes, as well as the spatial position deviation of the center of the spherical surface of the main ball seat ball head sleeve inner hole and the axis of the main ball seat shell inner hole; the spatial position deviations of both are controlled to ≤0.30mm, ensuring that when the main ball seat ball head sleeve and the main ball seat ball core are assembled together, the spatial position offset of the main ball seat ball head rotation center point and the intersection point of the two thrust rod shaft axes coinciding with each other is controlled to ≤0.65mm.

[0049] This dual-precision control strategy is based on the fact that the intersection point of the main ball joint's rotation center point and the axes of the two thrust rods is mainly determined by positioning the thrust rod intersection reference through the axis of the inner hole of the outer shell, and then calibrating the rotation origin of the main ball joint's rotation center point through the position of the center of the spherical surface of the inner hole of the main ball joint sleeve. The two work together to compress the accumulated error, so that the intersection point of the ball joint's rotation center point and the axes of the two thrust rods is controlled within the determined spatial position deviation range.

[0050] Furthermore, the spatial position deviation between the rotation center point of the main ball bearing and the intersection point of the axes of the two thrust rods is achieved by controlling the consistency between the machining accuracy of the inner hole of the main ball bearing shell and the assembly positioning reference. Specifically, a high-precision coordinate measuring machine is used to verify the spatial position of the inner hole axis in real time, and a laser tracker is used to dynamically monitor the intersection point of the thrust rod axes to ensure that the spatial deviation between the two is 0.65mm. At the same time, the deviation between the center of the spherical surface of the inner hole of the main ball bearing and the axis of the inner hole of the shell is controlled by ultra-precision grinding process and online contour detection closed-loop compensation, so that the single machining form and position error is stably suppressed within ±0.30mm.

[0051] Experiments have shown that limiting the cylindrical transition fit clearance between the main ball seat core and the main ball seat head spindle, controlling the fit clearance between 0.015mm and 0.035mm, ensures that the main ball seat core can be smoothly pushed into the spindle during assembly, avoiding assembly difficulties and spindle deformation caused by interference fit, while also effectively preventing loosening of the fit caused by excessive clearance. This further suppresses the axial movement space of the main ball seat core from the basic assembly level.

[0052] Furthermore, the aforementioned control of the spatial position deviation between the main ball joint's rotation center and the main ball joint's spindle axis also includes the machining and installation accuracy of the ball joint sleeve and the inner hole of the main ball joint housing, as well as the horizontal and vertical deviations between the main ball joint's rotation center and the main ball joint's spindle axis, both of which must be controlled within ≤0.30mm; ensuring that when the main ball joint sleeve and the main ball joint's core are assembled together, the offset of the main ball joint's rotation center coinciding with the intersection point of the axes of the two thrust rods is controlled within ≤0.65mm.

[0053] Furthermore, the secure installation of the main ball seat core and the main ball seat mandrel includes assembling the main ball seat core and the main ball seat mandrel together through a cylindrical transition fit, and strictly controlling the coaxiality and interference tolerance of the ball head mandrel and the ball head mandrel mounting hole, while controlling the spatial position deviation between the center of the outer spherical surface of the main ball seat core and the axis of the main ball seat mandrel to be ≤0.30mm.

[0054] The coaxiality and interference tolerance of the control ball head mandrel and the ball head mandrel mounting hole are achieved by using a hot fitting process combined with real-time force-displacement closed-loop monitoring by a servo press fitting machine. After assembly, a dual-frequency laser interferometer is used to detect the spatial position deviation of the center of the outer spherical surface of the main ball seat ball core relative to the axis of the main ball seat mandrel, ensuring that the radial and axial runout of the main ball seat ball core relative to the mandrel axis is ≤0.30mm after assembly.

[0055] Furthermore, the secure installation of the main ball seat core and the main ball seat head spindle also includes fixing the main ball seat core to the main ball seat head spindle from above using fastening bolts; after the main ball seat core is fitted onto the main ball seat head spindle through the inner hole of the core with an transition fit, the bottom surface of the inner hole step of the core is tightly attached to the upper step surface of the spindle, and then the fastening bolt passes through the center hole of the main ball seat core from above and extends into the threaded hole of the main ball seat head spindle near the flange mounting surface of the main ball seat, further locking and fixing the main ball seat core together to prevent loosening between the main ball seat core and the main ball seat head spindle.

[0056] The reason for tightening the bolts again after the main ball bearing core is fitted onto the main ball bearing head spindle via an intermediate fit through the core's inner hole is to prevent spatial misalignment between the main ball bearing head's rotation center point and the intersection of the two thrust rod axes. If the main ball bearing core and the main ball bearing head spindle become loose, the spatial position of the main ball bearing head's rotation center point will deviate from the intersection of the two thrust rod axes. This will affect the force acting on the thrust rod as it swings around the main ball bearing head's rotation center point, creating a prying force that loosens the main ball bearing core and the main ball bearing head spindle. Therefore, ensuring a stable fit between the main ball bearing core and the main ball bearing head spindle is crucial.

[0057] Currently, the main ball seat core and main ball seat mandrel are installed in a cylindrical shape. Most main ball seats also have fastening bolts, but they are mostly installed from the bottom of the main ball flange face upwards, using the main ball seat core as a nut. The main ball seat core and main ball seat mandrel are tightened together from bottom to top. Practical application has revealed some problems with this method. First, while installing the bolts from bottom to top is not inconvenient during the assembly of the thrust rod itself, once installed on the frame, with the flange face tightly against the axle, it is difficult to tighten the fastening bolts again if they loosen. The thrust rod flange must be loosened and pulled down before it can be tightened again. Second, installing the bolts from bottom to top... The current method of securing the main ball seat by tension is less effective than pressing it down from above. Furthermore, using the main ball seat as a nut limits the space at its upper part. To ensure thread locking, the upper part of the main ball seat must protrude upwards or downwards, significantly increasing manufacturing difficulty and affecting assembly accuracy. Existing designs use a tapered installation between the main ball seat and the ball head spindle. While some designs use top-down tightening, the limited upper space necessitates an arched cap to cover the main ball seat. This invention, however, uses a top-down pressing method, using bolts to tighten the main ball seat, resulting in greater stability. The nut, matching the bolt, is positioned at the flange end of the main ball seat spindle, further increasing the bolt's torsional resistance.

[0058] Furthermore, the threaded hole is located at one end of the main ball seat core near the main ball seat flange mounting surface through the inner hole of the core, and ensures that the thread engagement length between the threaded hole and the fastening bolt is greater than 20mm; moreover, the bottom surface of the bolt nut adopts a toothed texture structure to further increase the friction of the bolt and fully ensure the bolt's locking force.

[0059] Furthermore, the main ball seat core is fitted onto the ball head spindle via an transition fit, and is pressed and fixed from the main ball seat core by a clamping bolt, ensuring that the height of the bottom surface of the inner hole of the main ball seat core and the mounting surface of the main ball seat flange meets the requirement that the rotation center point of the main ball seat ball head is located at the horizontal position of the axis of the two thrust rods arranged in a "V" shape.

[0060] It should be noted that the above-listed embodiments are merely a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Furthermore, terms such as "upper," "lower," "front," "rear," and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention. Simultaneously, the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention. 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.

[0061] The beneficial effects of this invention are: 1. This invention, through strict control of the positional tolerances of key components, ensures that the coordinated control of all geometric tolerances ultimately targets a core objective: achieving sub-micron level coincidence between the rotation center of the main ball joint and the intersection point of the axes of the two thrust rods in three-dimensional space. This reduces the torque caused by eccentricity when the secondary ball joint in the V-shaped thrust rod oscillates relative to the main ball joint during operation after installation, effectively preventing the main ball joint from moving up and down, thus significantly increasing the stability of the thrust rod operation. 2. By controlling the alignment deviation between the main ball joint's rotation center and the thrust rod's axis, as well as the alignment deviation between the main ball joint's rotation center and the main ball joint's spindle axis, this invention employs a series of stringent tolerance controls and assembly processes. This not only significantly improves the service life of the V-type thrust rod under heavy load and high-frequency vibration conditions, but also reduces the abnormal wear rate of the ball core by 72% and brings the risk of disengagement close to zero in actual vehicle testing.

[0062] 3. This invention limits the positional offset (H) of the intersection point of the thrust rod's axis in a "V"-shaped arrangement to ≤0.65mm from the axis of the main ball joint's ball head sleeve. This effectively suppresses fretting wear of the ball core and significantly extends the service life of the ball joint. Combined with precision assembly tolerance control, the main ball joint maintains stable axial constraint stiffness across a wide temperature range of -40℃ to 120℃. The measured maximum ball core movement is reduced to within 0.08mm, improving stability by 62% compared to existing structures. This technological breakthrough not only solves industry pain points such as easy loosening, abnormal noise, and early failure of ball joints under heavy load conditions, but also upgrades assembly precision control from experience-based control to effective dimensional precision control through multi-dimensional collaborative tolerance allocation.

[0063] 4. In this invention, the main ball seat core is fitted onto the main ball seat head spindle via a cylindrical transition fit through the inner hole of the core. The main ball seat core and the main ball seat spindle are then pressed together by fastening bolts from the upper surface of the main ball seat core. Furthermore, the nut of the bolt and the bottom surface of the main ball seat core have a toothed texture structure to further increase the friction of the bolt and fully ensure the locking force of the bolt. This can further effectively suppress the vertical movement tendency of the main ball seat core and the main ball seat spindle, and improve the stability of the V-shaped thrust rod.

[0064] Under long-term vehicle vibration and heavy load impact, the V-shaped thrust rod structure underwent nearly 3 months of real vehicle road testing. Data shows that during 5,000 km of continuous full-load rough road testing, the V-shaped thrust rod did not exhibit any abnormal wear of the ball joint or excessive axial displacement, verifying the engineering reliability and mass production consistency of the design under extreme working conditions.

Claims

1. A method for improving the stability of a V-type thrust rod in a heavy-duty vehicle, wherein the V-type thrust rod is installed as an independent connecting component between the vehicle's axle and frame; wherein, The main ball joint of the V-shaped thrust rod is vertically mounted on the axle via a flange, and two auxiliary ball joints are hinged to the frame. The two V-shaped thrust rods oscillate adaptively through the main ball joint and auxiliary ball joints. Its key feature is that the axes of the two V-shaped thrust rods extend and intersect at the tips of the V-shaped thrust rods, ensuring that when the V-shaped thrust rod is installed on the truck, the point where the extended axes of the two V-shaped thrust rods intersect horizontally with the rotation center of the main ball joint's ball head. Simultaneously, the ball core of the main ball joint and the spindle of the main ball joint's ball head use a cylindrical transition fit, and the ball core of the main ball joint is fixed to the spindle from above using fastening bolts. By controlling the spatial positional deviation between the rotation center of the main ball joint's ball head and the point where the extended axes of the two thrust rods intersect, and by ensuring the stable installation of the ball core of the main ball joint and the spindle of the main ball joint's ball head, the vertical displacement tendency of the main ball joint's ball head center during operation is reduced, thus improving the stability of the V-shaped thrust rod for heavy-duty trucks.

2. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 1, characterized in that, The aforementioned control of the spatial position deviation of the main ball joint's rotation center and the intersection point of the extended axes of the two thrust rods is to control the spatial position deviation of the main ball joint's rotation center point and the intersection point of the axes of the two thrust rods to ≤0.65mm. The spatial position deviation refers to the spatial position deviation of the intersection point of the axes of the two thrust rods around the main ball joint's rotation center point, including the three-dimensional spatial position deviation of the sphere in the vertical, horizontal, and front-back directions, to ensure that the main ball joint's rotation center and the intersection point of the axes of the two thrust rods are as close as possible after the V-shaped thrust rod is installed.

3. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 2, characterized in that, The aforementioned control of the spatial position deviation between the center point of rotation of the main ball seat head and the intersection point of the axes of the two thrust rods to ≤0.65mm includes controlling the spatial position deviation between the intersection point of the axis of the inner hole of the main ball seat shell and the axis of the two thrust rods, and the spatial position deviation between the center of the spherical surface of the inner hole of the main ball seat head sleeve and the axis of the inner hole of the main ball seat shell; the spatial position deviations of both are controlled to ≤0.30mm, ensuring that when the main ball seat head sleeve and the main ball seat core are assembled together, the spatial position offset of the center point of rotation of the main ball seat head and the intersection point of the axes of the two thrust rods is controlled to ≤0.65mm.

4. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 3, characterized in that, The spatial position deviation between the rotation center point of the main ball bearing and the intersection point of the axes of the two thrust rods is achieved by controlling the consistency between the machining accuracy of the inner hole of the main ball bearing shell and the assembly positioning reference. Specifically, a high-precision coordinate measuring machine is used to verify the spatial position of the inner hole axis in real time, and a laser tracker is used to dynamically monitor the intersection point of the thrust rod axes to ensure that the spatial deviation between the two is 0.65mm. At the same time, the deviation between the center of the spherical surface of the inner hole of the main ball bearing and the axis of the inner hole of the shell is controlled by ultra-precision grinding process and online contour detection closed-loop compensation, so that the single machining form and position error is stably suppressed within ±0.30mm.

5. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 1, characterized in that, The aforementioned control of the spatial position deviation between the main ball joint's rotation center and the main ball joint's spindle axis also includes the machining and installation accuracy of the ball joint sleeve and the inner hole of the main ball joint housing, as well as the horizontal and vertical deviations between the main ball joint's rotation center and the main ball joint's spindle axis, both of which must be controlled within ≤0.30mm; ensuring that when the main ball joint sleeve and the main ball joint's core are assembled together, the offset of the main ball joint's rotation center coinciding with the intersection point of the axes of the two thrust rods is controlled within ≤0.65mm.

6. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 5, characterized in that, The secure installation of the main ball seat core and the main ball seat mandrel includes assembling the main ball seat core and the main ball seat mandrel together through a cylindrical transition fit, and strictly controlling the coaxiality and interference tolerance of the ball head mandrel and the ball head mandrel mounting hole, while controlling the spatial position deviation between the center of the outer spherical surface of the main ball seat core and the axis of the main ball seat mandrel to be ≤0.30mm.

7. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 6, characterized in that, The secure installation of the main ball seat core and the main ball seat head spindle also includes fixing the main ball seat core to the main ball seat head spindle from above using fastening bolts; after the main ball seat core is fitted onto the main ball seat head spindle through the inner hole of the core with an transition fit, the bottom surface of the inner hole step of the core is tightly attached to the upper step surface of the spindle, and then the fastening bolt passes through the center hole of the main ball seat core from above and extends into the threaded hole of the main ball seat head spindle near the mounting surface of the main ball seat flange, further locking and fixing the main ball seat core together to prevent loosening between the main ball seat core and the main ball seat head spindle.

8. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 7, characterized in that, The threaded hole is located at one end of the main ball seat core near the flange mounting surface of the main ball seat through the inner hole of the core; moreover, the bottom surface of the bolt nut adopts a toothed texture structure, which further increases the friction of the bolt and ensures that the thread engagement length between the threaded hole and the fastening bolt is greater than 20mm, thus fully guaranteeing the bolt's locking force.

9. The method for improving the stability of a V-shaped thrust rod in a heavy-duty vehicle according to claim 7, characterized in that, The main ball seat core is fitted onto the ball head spindle via an transition fit and is pressed and fixed from the main ball seat core by clamping bolts, ensuring that the height of the bottom surface of the inner hole of the main ball seat core and the mounting surface of the main ball seat flange is such that the center point of rotation of the main ball seat ball head is located at the horizontal position of the axis of the two thrust rods arranged in a "V" shape.

10. A V-shaped thrust rod for heavy-duty vehicles, comprising a main ball seat, a thrust rod body, and an auxiliary ball hinge. The thrust rod body consists of two rods arranged in a "V" shape, with one end connected together and the other ends separated to form a "V" shape. An auxiliary ball hinge is installed at each of the separated ends of the two thrust rod bodies. The outer shell of the main ball seat is connected to the end where the two thrust rod bodies are connected in the "V" shape. The key feature is that the intersection point of the axes of the two "V"-shaped thrust rod bodies overlaps with the rotation center of the ball head of the main ball seat, and the spatial offset between the intersection point of the thrust rod body axes and the rotation center of the ball head of the main ball seat is controlled to be ≤0.65mm.

11. The heavy-duty vehicle V-shaped thrust rod according to claim 10, characterized in that, The main ball seat includes a main ball seat head sleeve, a main ball seat core, a main ball seat head shell, and a main ball seat head spindle. The main ball seat head sleeve is installed inside the inner hole of the main ball seat head shell, and the axis of the inner hole of the shell intersects the axis of the main ball seat head spindle at an angle of less than 15 degrees. The bottom of the main ball seat head sleeve is limited by the bottom surface of the stepped inner hole of the main ball seat head shell, and the upper part is axially limited by a clamp. The main ball seat core and the main ball seat head spindle... A cylindrical transition fit is adopted. The main ball seat core is fitted onto the main ball seat head spindle through the inner hole of the core, and is locked and fixed from the upper surface of the main ball seat core downward by fastening bolts. The main ball seat head sleeve wraps around the outer spherical surface of the main ball seat core, forming a ball head pair. The rotation center of the ball head pair overlaps with the intersection point of the extension of the axes of the two thrust rods. After the V-shaped thrust rod is installed on the frame, the axes of the two thrust rods are in a horizontal state.

12. The V-shaped thrust rod for heavy-duty vehicles according to claim 11, characterized in that, The overlap between the ball head rotation center of the ball joint and the extended intersection point of the axes of the two thrust rods is to constrain the spatial distance (H) from the bottom surface of the inner hole step of the main ball head shell to the extended intersection point of the central axes of the two thrust rods, and the spatial distance (H) between the center of the main ball head sleeve 5 and the lower end face 23 of the main ball head sleeve. This ensures that when the main ball head sleeve is obliquely installed into the inner hole of the main ball head shell, the rotation center of the inner spherical surface of the main ball head sleeve overlaps with the extended intersection point of the axes of the two thrust rods.

13. The heavy-duty vehicle V-shaped thrust rod according to claim 12, characterized in that, The fastening bolt is tightened downwards from the upper surface of the main ball seat core. A threaded through-hole is located at the center of the main ball seat ball head mandrel, with the threaded portion situated near the flange mounting surface of the main ball seat. The main ball seat core has a two-stage inner bore at its center. The first stage inner bore is the central hole through which the fastening bolt passes, and the second stage inner bore is the inner bore of the main ball seat core that mates with the ball head mandrel. The main ball seat core is then installed onto the main ball seat ball head mandrel via an transition fit. After the main ball seat core inner hole is in contact with the upper step surface of the main ball seat head spindle, the fastening bolt is a locking screw with a toothed flat lower end face. When the inner plane of the main ball seat core inner hole contacts the upper surface of the main ball seat head spindle, the screw part of the fastening bolt passes through the main ball seat core center hole and is screwed onto the threaded hole of the main ball seat head spindle for locking and positioning, ensuring that the axes of the two thrust rods are in a horizontal state.

14. The heavy-duty vehicle V-shaped thrust rod according to claim 10, characterized in that, The horizontal alignment of the two thrust rods constrains the height of the upper surface of the main ball bearing mandrel and the depth of the inner hole of the main ball bearing mandrel. This ensures that when the main ball bearing mandrel is installed onto the main ball bearing mandrel via an adapter fit, the upper surface of the main ball bearing mandrel contacts the inner plane of the inner hole of the main ball bearing mandrel. The mandrel is then secured from above with fastening bolts, ensuring that the axes of the two thrust rods are horizontal after the V-shaped thrust rod is installed on the frame.

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