Method for prolonging service life of spacer in multi-layer rod end joint

Abstract

According to the method for prolonging the service life of the spacers in the multi-layer rod end joint, the radial bearing capacity of the two ends is improved by increasing the thicknesses of the two ends of the spacers on the outermost layer in the direction of an outer sleeve, and the starting point A for increasing the thickness of the spacers on the outermost layer is close to the perpendicular line between the end point of an outer convex arc S21 at the same end of the inner side wall of the outer sleeve and the axis of a mandrel; from the view of the axial section, a straight line section L11 is arranged between the point A and the end of the rod end joint to increase the thickness of the two ends of the spacer on the outermost layer, and the value range of the included angle E between the straight line section L11 and the axis of the mandrel is larger than or equal to 8 degrees and smaller than or equal to 18 degrees. The thicknesses of the two ends of the spacer are increased from the weak part of the spacer on the outermost layer, so that the radial bearing capacity of the two ends of the spacer is improved, meanwhile, the thickness is increased in a linear section mode, the inclination angle of the linear section is controlled, and the thickness of the spacer is increased as much as possible on the premise that enough deflection space is guaranteed; the radial bearing capacity of the spacer is improved to the maximum extent.

Description

Technical Field

[0001] The present invention relates to a method for improving the service life of a rod end joint, and in particular to a method for improving the service life of a spacer in a multi-layer rod end joint. Background Art

[0002] The rod end joint is the structure at the connection point of the vehicle's rod components. During the vehicle's movement, it will withstand complex load conditions such as radial, torsional, and deflection. For example, when the vehicle passes through a curve, the deformation of the rod end joint is needed to withstand torsional and deflection displacements, while also bearing radial loads.

[0003] Early rod end joints usually used metal joints, but metal joints have poor environmental adaptability, especially in dusty environments, which are prone to wear, resulting in reduced metal joint life and abnormal noise during use, thereby increasing vehicle maintenance costs. Therefore, current rod end joints usually use multi-layer rod end rubber joints, such as the series of patents previously applied for by the applicant: Application No. 202110790211X, Name "A multi-layer rod end ball joint and its design method", Application No. 2021107899371, Name "A method and structure for reducing the eccentric torsional stiffness of a multi-layer rod end ball joint", Application No. 2021107899390, Name "A method for improving the tensile strength of the rubber layer of a rod end ball joint", etc. This type of rod end joint has the advantages of large eccentric torsional deformation capability, certain radial load-bearing function, no abnormal noise, no wear, no rust, maintenance-free, and long service life.

[0004] However, the above structure also has problems. Figure 1 As mentioned above, in order to ensure the equal strain characteristics of the joint, make the lifespan of each joint structure as uniform as possible, and meet the convenience of modeling during production, a structure of spherical spacers of equal thickness and cylindrical outer sleeves is usually used. At the same time, in order to ensure the deflection characteristics of the joint, from a radial cross-sectional view, the structure of the inner wall of the outer sleeve is a straight line L1' parallel to the axis of the core shaft at both ends, and a convex arc S1' protruding toward the outer sleeve in the middle. The convex arc S1' and the straight line L1' are smoothly connected by an indented arc S2' that is concave toward the core shaft. This results in uneven rubber thickness at the two ends of the outermost layer, with the thickness of the thickest part H2 being more than three times that of the thinnest part H1. Therefore, the area corresponding to the convex arc S1' in the radial direction becomes the main load-bearing area. Under the condition of large radial load, the ends of the outermost spacer corresponding to the outer sleeve S1' are prone to breakage, affecting the overall lifespan of the joint. Summary of the Invention

[0005] The present invention addresses the problem that the outermost spacer of the current rod end joint is easy to break and thus has a short lifespan. A method for increasing the lifespan of the spacers in a multi-layer rod end joint is proposed, which can increase the strength of the outermost spacer and thus extend the service life of the joint.

[0006] The technical means adopted by the present invention to solve the above-mentioned problems are: a method for improving the service life of spacers in multi-layer rod end joints, by increasing the thickness of the outermost spacer at both ends toward the outer sleeve to improve the radial load-bearing capacity at both ends, and the starting point A for the increase in thickness of the outermost spacer is close to the perpendicular line between the end point of the convex arc S21 at the same end of the inner wall of the outer sleeve and the axis of the core shaft; from the axial cross-section, a straight line segment L11 is set between point A and the end of the rod end joint to increase the thickness at both ends of the outermost spacer, and the angle E between the straight line segment L11 and the axis of the core shaft is in the range of 8°≤E≤18°.

[0007] Furthermore, the distance D1 between the starting point A where the thickness of the outermost spacer increases and the perpendicular line between the end point of the convex arc S21 at the same end of the inner side wall of the outer sleeve and the axis of the core shaft is ≤5mm.

[0008] Furthermore, viewed from an axial cross-section, the outermost spacer's end near the outer sleeve is a straight segment L12 parallel to the core axis. Straight segments L11 and L12 are smoothly connected by an inwardly concave arc S13, which extends toward the core axis. The two endpoints of inwardly concave arc S13 are located on either side of the inwardly concave endpoint of the outermost rubber layer. This allows for maximum outermost spacer coverage while retaining sufficient deflection space, without affecting the deflection characteristics of the rod end joint.

[0009] Furthermore, viewed from an axial cross-section, the end of the outermost spacer near the outer sleeve is still an extension S11' of the convex arc S11 at the center of the outermost spacer. Line segment L11 and convex arc S11' are connected by line segment L13. Line segments L11 and L13 are smoothly connected by a convex arc S14 that bulges toward the outer sleeve. Line segment L13 and convex arc S11' are smoothly connected by a concave arc S15 that concave toward the core axis. The intersection of line segment L11 and convex arc S14 is close to the perpendicular between the concave end point of the outermost rubber layer and the core axis. This ensures that the outermost spacer thickness is increased wherever the outermost rubber layer is thicker, thereby maximizing the radial load-bearing capacity of the spacer.

[0010] Furthermore, a distance D2 between the intersection of the straight line segment L11 and the outward convex arc S14 and a perpendicular line between the inward concave end point of the outermost rubber layer and the axis of the core shaft is ≤7 mm.

[0011] Furthermore, from an axial cross-section, the convex arc S11 at the middle of the outermost spacer near the outer sleeve is smoothly connected to the straight segment L11 by an inward concave arc S12 that is concave toward the core axis, thereby achieving an angle range for the inclination of the straight segment L11.

[0012] Furthermore, a plurality of reinforcing ribs are provided along the axial direction of the core shaft on the side of the outermost spacer close to the core shaft, and a cavity without rubber filling is provided between each reinforcing rib and the spacer close to it, so as to offset the increase in rigidity caused by the reinforcing ribs.

[0013] Furthermore, the number of the reinforcing ribs is 6-10 and they are evenly arranged along the circumferential direction.

[0014] Furthermore, during vulcanization, the cavity is filled with a filler having a double-layer structure. After the vulcanization is completed, the inner layer structure of the filler is removed to form a cavity.

[0015] Furthermore, the filler of the double-layer structure is a high-temperature resistant sealing material coated on the periphery of the metal strip. After vulcanization is completed, the metal strip is removed to form a cavity.

[0016] Furthermore, each layer of spacers is divided into two equal parts, with the openings between adjacent spacers staggered at 60°. During vulcanization, six glue injection holes are set in each rubber layer. All glue injection holes at the same angle in all rubber layers form a straight glue injection line. The angle between two adjacent glue injection lines is 60°, and the spacer opening is located on the angle bisector of the angle between the two adjacent glue injection lines. This ensures balanced glue injection at the spacer opening.

[0017] The beneficial effects of the present invention are: 1. The present invention increases the radial load-bearing capacity of the outermost spacer at both ends by increasing the thickness starting from the weak point of the outermost spacer. At the same time, by increasing the thickness by using straight segments and controlling the inclination angle of the straight segments, the thickness of the spacer is increased as much as possible while ensuring sufficient deflection space, thereby maximizing the radial load-bearing capacity of the spacer.

[0018] 2. The thickness of the main load-bearing area in the middle region of the outermost spacer of the present invention remains unchanged; only the thickness at the two ends is increased. Therefore, the performance requirements of equal stress on the entire rod end joint can still be guaranteed. By increasing the load-bearing capacity at the two ends, the risk of the outermost spacer breaking at the point where the rubber thickness changes is reduced, thereby eliminating the weak points of the spacer.

[0019] 3. The present invention improves the strength of the spacer by arranging multiple reinforcing ribs on the side of the outermost spacer close to the core shaft. At the same time, the area between the reinforcing rib and the adjacent spacer is set as a cavity without rubber filling to offset the increase in stiffness brought by the reinforcing rib, so that the overall radial stiffness of the rod end joint is not affected.

[0020] 4. The present invention uses a double-layer filler in the cavity during vulcanization. After vulcanization is completed, only the inner layer structure needs to be removed, so that a cavity structure can be formed in a narrow and long space.

[0021] 5. The rubber layer of the present invention adopts six-point glue injection, and the glue injection lines are distributed at 60°, so that the distance from the glue injection points on both sides to the spacer opening is equal, so that the glue is filled at the spacer opening at the same time, avoiding the occurrence of undesirable phenomena such as misalignment of the product and uneven glue layer thickness, thereby ensuring product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of an axial cross section of the rubber between the rod end joint outer sleeve and the outermost spacer in the prior art (only the section line of the rubber layer is shown in the figure); Figure 2 Schematic diagram of an axial cross section of the rubber between the rod end joint outer sleeve and the outermost spacer in Example 1 (only the section line of the rubber layer is shown in the figure); Figure 3 for Figure 2 A partially enlarged schematic diagram showing the increased thickness of the outermost septum at both ends of the joint; Figure 4 This is a partially enlarged schematic diagram of Example 2 showing the outermost spacer with increased thickness at both ends of the joint; Figure 5 This is a partially enlarged schematic diagram of Example 3 showing the outermost spacer having increased thickness at both ends of the joint; Figure 6 This is a schematic radial cross-sectional view of the rod end joint spacer and the rubber layer of Example 4; Figure 7 for Figure 6 A partial enlarged schematic diagram; Figure 8 for Figure 7 Schematic diagram of filling the cavity during vulcanization; Figure 9 This is a schematic cross-sectional view along the axial direction of Example 4 when reinforcing ribs are provided on the outermost spacer (only the section lines of the rubber layer and the spacer are shown in the figure); Figure 10 for Figure 9 Schematic diagram of the filling of the cavity during vulcanization (only the cross-hatching of the rubber layer and the spacer is shown in the figure); Figure 11 Schematic diagram of the rod end joint of Example 5 along the axial end surface direction; Figure 12 for Figure 11 A partial enlarged schematic diagram; In the figure: 1. outer jacket, 2. outermost rubber layer, 3. outermost spacer, 31. reinforcing rib, 32. cavity, 33. filler, 4. core shaft, 5. boss, 6. spacer, 61. opening, 7. rubber layer, 8. glue injection hole, 81. glue injection line. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are schematic, not actual, representations. They should not be construed as limiting this patent. To better illustrate the embodiments of the present invention, some components in the accompanying drawings may be omitted, enlarged, or reduced in size, and do not represent the actual dimensions of the products. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted from the accompanying drawings. Example 1

[0024] A method for improving the life of spacers in multi-layer rod end joints, such as Figure 2 As shown, the rod end joint includes an innermost core shaft 4, an outermost outer shell 1, and a plurality of rubber layers 7 and spacers 6 located between the core shaft 4 and the outer shell 1. Figure 2 and Figure 3 As shown, in an axial cross-section, the outer sleeve 1 has an outward convex arc S21 at its center, with endpoints B at both ends. The inner sidewall of the outer sleeve 1 is formed by straight line segments L21 at both ends. Between the outward convex arc S21 and the straight line segments L21 lies an inward concave arc S22 that is concave toward the core axis 4. The outermost spacer 3, located in the center near the outer sleeve 1, has a convex arc S11 that bulges toward the outer sleeve 1.

[0025] In order to improve the strength of the outermost spacer 3, in this embodiment, Figure 2 and Figure 3 As shown, from an axial cross-section, the length of the convex arc S11 is controlled to point A. The shape of the point A near the rod end joint is configured so that a straight line segment L11 smoothly connects to the convex arc S11. The angle E between the straight line segment L11 and the core axis is controlled within a range of 8° ≤ E ≤ 18°. This prevents E from being too small, resulting in insufficient deflection space and weakening the product's deflection load-bearing capacity, while also preventing E from being too large, resulting in a minimal increase in the thickness of the outermost spacer 3 and failing to improve its radial load-bearing capacity. At this point, the straight line segment L11 is tangent to the convex arc S11 at point A, effectively forming a tangent to the convex arc S11 and ensuring a smooth connection between the two. Furthermore, the distance D1 between the perpendiculars between point A and point B and the core axis must satisfy the requirement of D1 ≤ 5 mm. This ensures that the thickness of the outermost spacer 3 is increased starting from the weakest point, effectively improving its radial load-bearing capacity.

[0026] In this embodiment, Figure 3As shown, from the axial cross-section, the shape of the end portion of the outermost spacer 3 close to the outer sleeve side is set to be a straight line segment L12 parallel to the core shaft axis, and the straight line segment L12 is smoothly connected to the straight line segment L11 by an inward concave arc S13 concave toward the core shaft 4, and the intersection point C1 between the inward concave arc S13 and the straight line segment L11, and the intersection point C2 between the inward concave arc S13 and the straight line segment L12 are respectively located on both sides of the perpendicular line V between the inward concave end point of the outermost rubber layer and the core shaft axis, so that the contact surface between the outermost spacer 3 and the outermost rubber layer 2 at the position with greater rubber thickness is the straight line segment L11 with an angle E, so that the outermost spacer 3 is This interval is a structure with a thickness that slowly increases from the middle to both ends. In the same radial direction, the greater the rubber thickness, the greater the thickness of the outermost spacer 3. While ensuring the deflection deformation space, when subjected to radial load, the outer sleeve 1 squeezes the outermost rubber 2, and the deformation at both ends of the outermost rubber 2 is reduced due to the reduced rubber thickness. When loaded, the ability to transfer the load to the outermost spacer 3 is enhanced. At the same time, due to the increased thickness of the outermost spacer 3 here, it can withstand a greater load, thereby reducing the load on the outermost spacer 3 in the outer convex arc S11 interval. Therefore, the service life of the outermost spacer 3 can be extended. Example 2

[0027] This embodiment is basically the same as the above embodiment, except that: Figure 4 As shown, from the axial cross-section, the convex arc S11 of the outermost spacer 3 close to the outer sleeve 1 is smoothly connected to the straight segment L11 through the concave arc S12 recessed toward the core shaft 4. This is because, in order to ensure that the angle range of the straight segment L11 is 8°≤E≤18°, the straight segment L11 and the convex arc S11 can be smoothly connected to avoid the smoothness of the surface of the outermost rubber 2 at this location and thus avoid wrinkles or cracks. However, if the distance D1 between the perpendicular lines between point A and point B and the axis of the core shaft meets the required range, the tangent of the convex arc S11 at point A cannot always meet the requirement between 8° and 18°. At this time, the concave arc S12 is required to achieve the connection between the straight segment L11 and the convex arc S11. Example 3

[0028] This embodiment can be a modification of the first embodiment or a modification of the second embodiment. Figure 5As shown, from the axial cross section, the end of the outermost spacer 3 close to the outer sleeve 1 in this embodiment is still an extended convex arc S11' of the convex arc S11, that is, the center and radius of the convex arc S11' are the same as those of the convex arc S11. At this time, in order to ensure a smooth connection between the straight segment L11 and the convex arc S11', a straight segment L13 is set between the straight segment L11 and the convex arc S11', and the straight segment L11 and the straight segment L13 are connected by an convex arc S14 convex toward the outer sleeve 1, and the straight segment L13 and the convex arc S11' are connected by an inward concave arc S15 concave toward the core shaft 4. In this way, a boss 5 is formed between the convex arcs S14. At the same time, by controlling the position of the intersection C3 between the straight segment L11 and the convex arc S14, the boss 5 is positioned as close to the end of the rod end joint as possible to increase the radial load-bearing capacity of the outermost spacer 3 as much as possible. At this time, the distance D2 between C3 and the perpendicular line V between the inward concave end point of the outermost rubber layer and the axis of the core shaft is required to be ≤7mm. Since the outermost rubber layer 2 corresponding to the convex arc S11' in the same diameter direction is an inwardly concave structure, the rubber here basically cannot play a role in transmitting radial loads. It is mainly used for connection with the outer sleeve 1 and the outermost spacer 3, and also has the function of stress release. Therefore, the outermost spacer 3 adopts the shape of the convex arc S11' without basically affecting the overall load-bearing capacity. Example 4

[0029] This embodiment may be an improvement on any of the above embodiments, such as Figure 6 and Figure 7 As shown, multiple reinforcing ribs 31 are provided on the side of the outermost spacer 3 facing the core shaft 4. These ribs 31 are arranged axially along the core shaft 4 and evenly spaced circumferentially. The number of ribs 31 can range from 6 to 10, depending on the size of the rod end joint and the load requirements. While the addition of ribs 31 provides support for the outermost spacer 3 and improves load-bearing capacity, it reduces the distance between adjacent spacers 6, thus shortening the compression stroke. Therefore, a cavity 32 is formed between the rib 31 and the adjacent spacer 6. When subjected to radial loads, the entire cavity 32 can be compressed, thus minimizing overall performance.

[0030] Since the thickness of the rubber layer 7 in this product is relatively thin, and the thickness of the cavity 32 is even smaller, and Figure 9 As shown, the cavity 32 is in the shape of a curved long and narrow strip. Therefore, during vulcanization, if a conventional mold part is used to fill the cavity 32, it is very likely that the mold part cannot be removed after vulcanization is completed, and thus the cavity 32 cannot be formed. In order to avoid this situation, as shown in FIG. Figure 8 and Figure 10As shown, during vulcanization, the filler 33 in the cavity 32 can be made by wrapping a high-temperature resistant sealing material around a slender metal strip. The metal strip provides support, and the high-temperature resistant sealing material isolates the rubber from the metal strip. When vulcanization is completed, the metal strip is pulled out to form the cavity 32. The high-temperature resistant sealing material can remain in the cavity 32 without affecting the performance. At the same time, it can also isolate the reinforcing rib 31 and the spacer 6 from the outside world, thereby playing a protective role. Example 5

[0031] This embodiment is an improvement on the rod end joint forming method. Figure 11 and Figure 12 As shown, each spacer 6 is divided into two equal parts, with two openings 61 formed between two spacers 6 on the same layer. The openings 61 between two adjacent layers of spacers 6 are staggered at 60°. During vulcanization, six injection holes 8 are evenly arranged in each rubber layer 7. A straight injection line 81 is formed between all injection holes 8 at the same angle in all rubber layers 7. The angle between two adjacent injection lines 81 is 60°, and the opening 61 of the spacer 6 is located on the bisector of the angle between the two adjacent injection lines 81. In this way, the distance between an opening 61 and the four adjacent injection holes 8 is basically the same. During vulcanization, the rubber material from the four nearby injection holes 8 can basically reach the same opening 61 at the same time, so that the rubber material is filled in the opening 61 at the same time, achieving a balanced injection state, and avoiding misalignment or uneven rubber layer thickness at the opening 61. Example 6

[0032] In this embodiment, the relationship between the radial limit fatigue load F (where the fatigue times are 2 million times) that the product bears and the thickness H and width L of the jacket 1 is: F=2.35L+4.15H-84, with L≥28mm and H≥7mm being limited, so that the formed rod end joint can not only meet the assembly space requirements, but also avoid excessive deformation of the jacket 1 when bearing load.

[0033] The above embodiments are only for the purpose of illustrating the present invention, and are not intended to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of protection of the present invention, and the scope of protection of the present invention should be defined by the claims.

Claims

1. A method for improving the service life of a spacer in a multi-layer rod end joint, characterized in that: The radial load-bearing capacity at both ends is improved by increasing the thickness of the outermost spacer (3) at both ends in the direction of the outer sleeve (1), and the starting point A of the thickness increase of the outermost spacer (3) is close to the perpendicular line between the end point of the outer convex arc S21 at the same end of the inner side wall of the outer sleeve (1) and the core shaft axis; From the axial cross section, a straight line segment L11 is provided between point A and the end of the rod end joint to increase the thickness at both ends of the outermost spacer (3), and the angle E between the straight line segment L11 and the axis of the core shaft (4) is in the range of 8°≤E≤18°.

2. The method for improving the service life of a multi-layer rod end joint spacer according to claim 1, wherein: The distance D1 between the starting point A where the thickness of the outermost spacer (3) increases and the perpendicular line between the end point of the convex arc S21 at the same end of the inner side wall of the outer sleeve (1) and the axis of the core shaft (4) is ≤5mm.

3. The method for improving the service life of a multi-layer rod end joint spacer according to claim 1, wherein: From the axial cross section, the end of the outermost spacer (3) close to the outer sleeve (1) is a straight line segment L12 parallel to the axis of the core shaft (4), and the straight line segment L11 and the straight line segment L12 are smoothly connected by an inward concave arc S13 that is concave toward the core shaft (4), and the two end points of the inward concave arc S13 are respectively located on both sides of the inward concave end point of the outermost rubber (2).

4. The method for improving the service life of a multi-layer rod end joint spacer according to claim 1, wherein: From the axial cross section, the end of the outermost spacer (3) close to the outer sleeve (1) is still an extension S11' of the convex arc S11 at the middle of the outermost spacer (3), and the straight line segment L11 and the convex arc S11' are connected by a straight line segment L13. At the same time, the straight line segment L11 and the straight line segment L13 are smoothly connected by a convex arc S14 convex toward the outer sleeve (1), and the straight line segment L13 and the convex arc S11' are smoothly connected by an indented arc S15 concave toward the core shaft (4), and the intersection between the straight line segment L11 and the convex arc S14 is close to the perpendicular line between the indented end point of the outermost rubber (2) and the axis of the core shaft (4).

5. The method for improving the service life of a multi-layer rod end joint inner spacer according to claim 4, characterized in that: The distance D2 between the intersection of the straight line segment L11 and the convex arc S14 and the perpendicular line between the concave end point of the outermost rubber layer (2) and the axis of the core shaft (4) is ≤7 mm.

6. The method for improving the service life of a multi-layer rod end joint inner spacer according to claim 3 or 4, characterized in that: From the axial cross section, the convex arc S11 and the straight line segment L11 at the middle of the outermost spacer (3) close to the outer sleeve (1) are smoothly connected by the concave arc S12 that is concave toward the core axis (4).

7. The method for improving the service life of a multi-layer rod end joint spacer according to claim 1, wherein: A plurality of reinforcing ribs (31) are arranged axially along the core shaft (4) on one side of the outermost spacer (3) close to the core shaft (4), and a cavity (32) not filled with rubber is provided between each reinforcing rib (31) and the spacer (6) close thereto.

8. The method for improving the service life of a multi-layer rod end joint inner spacer according to claim 7, characterized in that: During vulcanization, the cavity (32) is filled with a filler (33) having a double-layer structure. After the vulcanization is completed, the inner layer structure of the filler (33) is removed to form the cavity (32).

9. The method for improving the service life of a multi-layer rod end joint inner spacer according to claim 8, characterized in that: The double-layer filler (33) is a high-temperature resistant sealing material coated on the outer periphery of the metal strip. After vulcanization is completed, the metal strip is removed to form a cavity.

10. The method for improving the service life of a multi-layer rod end joint spacer according to claim 1, wherein: Each layer of spacer (6) is equally divided into two lobes, and the openings (61) between two adjacent layers of spacer (6) are staggered at 60 degrees. During vulcanization, six glue injection holes (8) are set in each rubber layer (7), and a straight glue injection line (81) is formed between all the glue injection holes (8) at the same angle of all rubber layers (7). The angle between two adjacent glue injection lines (81) is 60 degrees, and the opening (61) of the spacer (6) is located on the angle bisector of the angle between the two adjacent glue injection lines (81).

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