Load stabilizer and fatigue bench test system

Abstract

A load stabilizer and a fatigue bench test system, the load stabilizer comprising a cylinder, a first end cover and a second end cover threadedly connected to two ends of the cylinder, an installation seat with a guide rod and a spring sleeved on the guide rod being arranged between the first end cover and the second end cover in the cylinder, a bushing being mounted in a bore of the second end cover, the guide rod extending out of the bushing and being provided with an external thread at an end portion, a nut being mounted on the external thread, and an outer diameter of a gasket between the nut and the second end cover being greater than an outer diameter of the bushing. The fatigue bench test system has a vertical loading point, a reciprocating fatigue load connecting point, and the load stabilizer described above, the load stabilizer being connected with a joint bearing of the vertical loading point via a threaded bore of the first end cover, and being connected with one end of a connecting rod provided with an internal thread via the thread of the end portion of the guide rod, the other end of the connecting rod being connected with a force sensor. The load stabilizer is small and moderate, convenient to install and disassemble, and two load stabilizers can be used in series to obtain smaller load deviation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steering knuckle bench test, more particularly to a load stabilizer. BACKGROUND

[0002] The automobile steering knuckle is one of the main parts in the automobile suspension system, which is connected with automobile connecting rods, bearings, wheel hubs and brake assemblies, and has the functions of bearing the front and rear loads of the automobile, supporting and driving the wheel hub to rotate, and realizing flexible steering and normal driving of the automobile. The reliability of the steering knuckle directly affects the normal driving of the automobile and the safety of the people on board, especially the steering knuckle is subjected to variable impact and fatigue load in the driving state of the automobile, so higher requirements are put forward for the strength, fatigue, stiffness and mechanical properties of the steering knuckle. Therefore, one of the most important works in the product development cycle is to verify whether the fatigue life and strength of the product can meet the needs of various working conditions. With the accelerated development of various vehicle models, the development cycle of vehicle models is becoming shorter and shorter, and it is an urgent need for the development of the automobile industry to continuously strengthen the research and development of the steering knuckle bench test and improve the mechanical properties of the steering knuckle to meet the needs of various road conditions. The automobile manufacturers have gradually formed two verification schemes, one is to simulate the automobile suspension test bench, and the other is to test each single hole of the steering knuckle. Among them, about one third of the test benches simulating the automobile suspension are double-channel test benches. The double-channel mainly respectively simulates the vertical static load and the cyclic loading of the grounding point. The vertical static load simulates the load received by the steering knuckle in the vertical direction, which is generally the distribution of the weight of the vehicle on a single steering knuckle. The cyclic loading of the grounding point simulates the turning or braking of the vehicle. In order to accurately apply the vertical static load in the double-channel fatigue test of the steering knuckle, special devices need to be added for assistance, otherwise there will be a large error in the vertical static load during the fatigue test. SUMMARY

[0003] To solve the above problems, the purpose of the present application is to provide a load stabilizer which, when used alone, can stabilize the vertical load error in the double-channel fatigue test within ±0.5kN, and generally maintain the error within ±0.3kN. Two load stabilizers can also be used in series to obtain smaller load deviation.

[0004] According to one aspect of the present application, a load stabilizer includes a cylinder, a first end cover and a second end cover threadedly connected to two ends of the cylinder respectively, a mounting seat with a guide rod and a spring sleeved on the guide rod are arranged between the first end cover and the second end cover in the cylinder, a bushing is mounted in the inner hole of the second end cover, the guide rod extends from the bushing and is provided with an external thread at the end, a nut is mounted on the external thread, and the outer diameter of the gasket between the nut and the second end cover is greater than the outer diameter of the bushing.

[0005] Preferably, the spring is a die spring with a rectangular cross-section, and / or the bushing is a self-lubricating graphite copper sleeve.

[0006] Preferably, the spring has an outer diameter of 50 mm, an inner diameter of 25 mm, a length of 200 mm, and / or a stiffness of 0.153 kN / mm to 0.307 kN / mm.

[0007] Preferably, the first end cap is centrally provided with a threaded inner hole, and / or the outer wall of the cylinder is provided with an observation hole for observing the internal spring.

[0008] Preferably, the mounting base further comprises a base connected to the stud and the guide rod, the base having an outer diameter smaller than the inner diameter of the cylinder.

[0009] Preferably, the first end cap and the cylinder are provided with locking platforms, and / or the base and the guide rod are provided with locking platforms.

[0010] According to another aspect of the present application, there is provided a fatigue bench test system for two-channel or more steering knuckle fatigue bench test, characterized in that it comprises a vertical loading point, a reciprocating fatigue load connection point, and the load stabilizer described above, which is connected to the joint bearing of the vertical loading point via the threaded inner hole of the first end cap, and is connected to one end of the link rod provided with an internal thread via the thread of the end of the guide rod, and the other end of the link rod is connected to the force sensor.

[0011] Preferably, the two load stabilizers are connected in series to the vertical loading point.

[0012] Preferably, the depth of the internal thread hole of the link rod is greater than the remaining length after the installation of the guide rod nut.

[0013] Preferably, the reciprocating fatigue load connection point is the grounding point, the wheel center position, or the position of 2 times the wheel rolling radius.

[0014] The load stabilizer is small and moderate in size, and is convenient to install and disassemble. When used alone, the vertical load error in the two-channel fatigue test of the steering knuckle is stabilized within ±0.5 kN from ±2-4 kN (or more), and the error can generally be maintained within ±0.3 kN. If two are used in series, the error can be basically maintained within ±0.3 kN. The general error of ±0.5 kN will not affect the test results. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the drawings and examples.

[0016] Figure 1 is a sectional view of the load stabilizer of the present application.

[0017] Figure 2 is a sectional view of the load stabilizer of the present application.

[0018] Figure 3The working condition diagram of the double-channel test bench using a load stabilizer is shown schematically.

[0019] Figure 4 The working condition diagram of the double-channel test bench using two load stabilizers in series is shown schematically.

[0020] In the figure: 1-end cover, 2-cylinder, 3-base, 4-stud, 5-guide rod, 6-mold spring, 7-end cover, 8-self-lubricating graphite copper sleeve, 9-washer, 10-nut, 11-load stabilizer. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present application are described in detail below with reference to the accompanying drawings. The exemplary embodiments described below and illustrated in the drawings are intended to teach the principles of the present application, with the understanding that the present application can be adapted or modified as necessary by those skilled in the art for use in a variety of different possible environments and for a variety of different possible applications. Therefore, the present application is not limited to the specific exemplary embodiments described below, but only by the scope of the appended claims. Furthermore, for the purposes of simplicity and clarity, identical members referred to in the various embodiments are identified by the same or similar reference numerals, and the size of each part shown in the drawings is not necessarily to scale, and the orientation of the various parts described below is based on the orientation shown in the drawings, and is merely intended to facilitate the description of the present application and to simplify the description, and is not intended to indicate or imply that the device or the member must be constructed and operated in a particular orientation. The description of each embodiment below focuses on the differences between the various embodiments, and the same or similar parts can be referred to each other, and for brevity, will not be repeated, and the technical features in each different embodiment can be freely combined to form more embodiments according to design needs.

[0022] In the double-channel fatigue test of the knuckle, the error of the vertical static load ±2-4kN is caused by the movement of the loading arm driven by the cyclic load at the grounding point, which generates a certain displacement (generally within ±2mm) at the vertical load loading point. The movement of the vertical load loading point will inevitably stretch or compress the load sensor, causing the vertical load value to change. The current test control system cannot stabilize the vertical static load within a small error range during the test.

[0023] According to the present application, a load stabilizer 11 is provided, comprising: a cylinder body 2, a first end cover 1 and a second end cover 7 threadedly connected to both ends of the cylinder body 2, a mounting seat with a guide rod 5 and a spring 6 sleeved on the mounting seat arranged between the first end cover 1 and the second end cover 7 in the cylinder body 2, a self-lubricating graphite copper sleeve 8 mounted in the inner hole of the second end cover 7, the guide rod 5 extending from the self-lubricating graphite copper sleeve 8 and provided with an external thread at the end portion stopping at the position of the self-lubricating graphite copper sleeve 8, a nut 10 mounted on the external thread, and a gasket 9 with an outer diameter larger than the outer diameter of the self-lubricating graphite copper sleeve 8 arranged between the nut 10 and the second end cover 7.

[0024] More specifically, as shown in Figure 1 , the first end cover 1 and the cylinder body 2 are threadedly connected, and the first end cover 1 and the cylinder body 2 are provided with platforms for wrench operation, facilitating locking. The first end cover 1 is provided with a threaded inner hole 15 at the center for external connection, for example, joint bearing connection with the vertical loading point 12 of the double-channel test bench as described below (see Figure 3 、 Figure 4 .

[0025] The base 3 and the guide rod 5 are locked and connected by the stud 4, and the base 3 and the guide rod 5 are provided with platforms for wrench operation, facilitating locking. The outer circle of the base 3 is provided with a gap with the inner wall of the cylinder body 2 to prevent interference during movement.

[0026] The spring 6 is sleeved on the guide rod 5, the base 3, the guide rod 5 and the spring 6 are put into the cylinder body 2, and the spring 6 is spaced apart from the outer diameter of the guide rod 5 and the inner diameter of the cylinder body 2 by a gap, which ensures that the spring 6 will not interfere with the outer diameter of the guide rod 5 and the inner diameter of the cylinder body 2 after being completely compressed. The outer wall of the cylinder body 2 is provided with multiple observation holes for observing the movement of the internal spring 6 to prevent the spring 6 from being completely compressed.

[0027] The spring 6 is preferably a die spring with a rectangular cross section, and the rectangular cross section cylindrical spiral compression spring has a larger cross-sectional area than the circular cross section cylindrical spiral compression spring in the same space, so it can absorb more energy. On the other hand, the characteristic curve of the rectangular cross section cylindrical spiral compression spring is closer to a straight line, i.e. the stiffness of the spring is closer to a fixed constant. In addition, the rectangular cross section spring has good stability and fatigue resistance. The length, wire diameter, inner and outer diameters of the internal die spring can be customized and adjusted according to actual conditions, and appropriate spring stiffness is selected to ensure load error.

[0028] In one embodiment, the spring is selected to have an outer diameter of 50 mm, an inner diameter of 25 mm, a length of 200 mm, a stiffness of 0.153 kN / mm to 0.307 kN / mm, for example, three different stiffnesses of 0.153 kN / mm, 0.245 kN / mm, and 0.307 kN / mm, corresponding to limit loads of 7.4 kN, 9.8 kN, and 12.3 kN, respectively. The three springs basically cover most of the test requirements, and can ensure that the stress value meets the requirements of the bench test. One can be selected according to the size of the vertical static load, or a combination of the three can be selected. In this way, the strength of the spring peripheral part is ensured, and the spring is not too small to play a role, or the spring is too large and too long to occupy space.

[0029] The self-lubricating graphite copper sleeve 8 is placed in the inner hole of the second end cover 7, the outer wall of the self-lubricating graphite copper sleeve 8 and the inner hole of the second end cover 7 are in interference fit, the guide rod 5 passes through the self-lubricating graphite copper sleeve 8, the second end cover 7 and the cylinder 2 are connected by threads, the flange part of the second end cover 7 is provided with a platform for wrench operation, which is convenient for locking. The guide rod 5 and the self-lubricating graphite copper sleeve 8 are in clearance fit. The end of the guide rod 5 is provided with external threads, and the root of the external threads is cut off at the position of the self-lubricating graphite copper sleeve 8. The self-lubricating bearing is used, and after the first installation and the addition of appropriate amount of lubricating grease, the lubricating grease does not need to be added frequently.

[0030] The gasket 9 is passed through the guide rod 5 and contacted with the second end cover 7, the outer diameter of the gasket 9 is greater than the outer diameter of the self-lubricating graphite copper sleeve 8, and there is a pre-tightening force at this position, or a misoperation generates a pressure load, which is borne by the second end cover 7. The nut 10 is screwed on the threaded end of the guide rod 5, and after being contacted with the gasket 9, it is slightly locked and generates a little pre-tightening force, so that there is no gap between the nut 10, the gasket 9 and the second end cover 7, to prevent the operator from misoperating and damaging the load stabilizer by external force pressing the guide rod 5 during the test. This load stabilizer can only bear tensile load.

[0031] The above self-lubricating graphite copper sleeve 8 is described by way of example, but is not limited thereto, and only the sleeve with the appropriate structure and shape described above can be used.

[0032] The connected load stabilizer 11 is connected to the joint bearing of the vertical loading point 12 of the double-channel test bench via the threaded hole 15, and the other end of the load stabilizer 11 is connected to the force sensor 13 through a connecting rod provided with an internal thread and connected to the threaded end of the guide rod 5. During the test, the position of the double-channel grounding point 14 applies a sinusoidal reciprocating load F1, and the vertical loading point 12 applies an outward static load F2. The reciprocating load movement of the grounding point 14 position causes the displacement of the vertical loading point 12, which is absorbed by the spring 6, and the load generated by the length change of the spring 6 does not exceed ±0.5kN, generally ±0.3kN, which does not excessively pull and press the force sensor 13, causing excessive deviation of the vertical load. If necessary, two load stabilizers can be connected in series (see Figure 4 ), to obtain smaller load deviation, and the connecting rod can be a short connecting rod to avoid excessive overall size.

[0033] The above illustrates that the base 3 and the guide rod 5 are connected by the stud 4, but it is not limited to this, and the base 3 and the guide rod 5 can be integrally provided to form a mounting seat, or the base 3 and the stud 4 can be integrally provided to form a mounting seat.

[0034] In addition, the depth of the internal threaded hole of the connecting rod is greater than the remaining length after the guide rod 5 mounting nut 10, so that in the initial installation state, the connecting rod can be locked to the nut 10 to prevent the nut 10 from loosening under stress in the test state.

[0035] The above describes the double-channel fatigue bench test of the steering knuckle as an example, but it is not limited to this, and the load stabilizer according to the present application can also be applied to double-channel or more than three multi-channel fatigue bench tests of other loading forms requiring static load.

[0036] The above describes the reciprocating fatigue load connection point with the grounding point 14 (usually referring to the point generated by the wheel hub along the steering knuckle flange facing downward to the vehicle, through a wheel rolling radius distance) as an example, but it is not limited to this, and it can also be loaded at the wheel hub position or 2 times the wheel rolling radius position according to customer requirements.

[0037] In the description of the application, the meaning of "multiple" is two or more than two, unless otherwise expressly specifically limited. Unless otherwise expressly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in this application can be understood according to the specific circumstances. Although the present application has been described with reference to various specific embodiments, it should be understood that modifications can be made within the spirit and scope of the described inventive concept. Therefore, it is intended that the present application is not limited to the described embodiments, but will have the full scope defined by the language of the appended claims.

Claims

1. A load stabilizer characterized by, The device comprises a cylinder (2), a first end cover (1) and a second end cover (7) threadedly connected to both ends of the cylinder (2), a mounting seat with a guide rod (5) and a spring (6) sleeved on the guide rod (5) arranged between the first end cover (1) and the second end cover (7) in the cylinder (2), a bushing (8) mounted in the inner hole of the second end cover (7), the guide rod (5) extending out of the bushing (8) and being provided with external threads at the end, a nut (10) mounted on the external threads, the outer diameter of a washer (9) between the nut (10) and the second end cover (7) being greater than the outer diameter of the bushing, The mounting seat comprises a base (3), and a gap is arranged between the outer circle of the base (3) and the inner wall of the cylinder (2), The spring (6) is arranged in the cylinder (2) in a manner that it can be compressed between the end faces of the base (3) and the second end cover (7) opposite to each other, and a gap is arranged between the spring (6) and the outer diameter of the guide rod (5) and the inner diameter of the cylinder (2), The spring (6) is a die spring with a rectangular cross section, The spring (6) has an outer diameter of 50 mm, an inner diameter of 25 mm, a length of 200 mm, and / or a stiffness of 0.153 kN / mm to 0.307 kN / mm, The load stabilizer (11) is connected with the joint bearing of the vertical loading point (12) via the threaded inner hole (15) of the first end cover (1), the vertical loading point (12) is the loading point of the load stabilizer (11) to which the outwardly pulling static load (F2) is applied, the displacement of the vertical loading point (12) is absorbed by the spring (6), and the load generated by the length change of the spring (6) is not more than ±0.5 kN.

2. The load stabilizer of claim 1, wherein The bushing is a self-lubricating graphite copper sleeve (8).

3. The load stabilizer of claim 1, wherein The load generated by the length change of the spring (6) is not more than ±0.3 kN.

4. The load stabilizer of claim 1, wherein The first end cover (1) is provided with a threaded inner hole (15) in the center, and / or the outer wall of the cylinder (2) is provided with an observation hole for observing the internal spring (6).

5. The load stabilizer of claim 1, wherein The mounting seat further comprises a base (3) connected by a stud (4) and a guide rod (5), and the outer diameter of the base (3) is smaller than the inner diameter of the cylinder (2).

6. The load stabilizer of claim 5, wherein The first end cover (1) and the cylinder (2) are provided with locking platforms, and / or the base (3) and the guide rod (5) are provided with locking platforms.

7. A fatigue rig test system for two or more channel knuckle fatigue rig testing, characterized by, The device comprises a vertical loading point (12), a reciprocating fatigue load connection point (14), and the load stabilizer (11) of any one of claims 1 to 6, the load stabilizer (11) being connected with one end of a connecting rod provided with internal threads via the threads at the end of the guide rod (5), the other end of the connecting rod being connected to a force sensor (13), the reciprocating fatigue load connection point being a grounding point, a wheel center position, or a position twice the rolling radius of a wheel, and the grounding point being a point at which the wheel center is away from the flange of the steering knuckle and downwardly to the vehicle by a distance of one rolling radius of the wheel.

8. The fatigue test bench system of claim 7, wherein, Two load stabilizers (11) are connected in series to the vertical loading point (12).

9. The fatigue test bench system of claim 7, wherein, The depth of the internal threaded hole of the connecting rod is greater than the remaining length of the guide rod (5) after the nut (10) is mounted.

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