Rolling-sliding contact friction-wear test device based on epicyclic gear train

Abstract

The invention discloses a rolling-sliding contact friction-wear test device based on an epicyclic gear train. The rolling-sliding contact friction-wear test device comprises a central gear, planetary gears, a gear ring, an upper gear, balls, an inner raceway, an outer raceway, a first motor, a second motor and a third motor, an annular groove matched with the balls is formed between the outer raceway and the inner raceway; the first motor is connected with the central gear through a central shaft; the inner raceway is coaxially fixed with the central gear; the second motor is connected with the upper gear; the outer raceway is provided with outer gear teeth, the gear ring is provided with outer gear teeth and inner gear teeth, and the outer raceway and the gear ring are coaxially fixed; the upper gear is meshed with the outer roller path and the outer gear teeth of the gear ring; the third motor is connected with the planet carrier; a plurality of planet gears are arranged on the planet carrier at equal intervals in the circumferential direction; the planetary gear is meshed with the sun gear and the inner gear teeth of the gear ring and is fixed with one ball; according to the invention, the ball movement condition of the ball in a ball screw and other similar mechanical structures can be simulated.

Description

Technical Field

[0001] This invention belongs to the field of friction and wear measurement, and in particular to a rolling-sliding contact friction and wear test device based on a planetary gear system. Background Technology

[0002] With the widespread application of mechanical components containing rolling elements, such as ball screws and rolling bearings, the amount of friction and wear experienced by these rolling elements affects the performance of these mechanical components. Therefore, friction and wear testing of rolling elements is crucial. In the field of friction and wear measurement, common measurement methods mainly target sliding friction. Test instruments used in the field of rolling friction measurement generally cannot accurately control pure rolling or the roll-slip ratio.

[0003] The fatigue performance testing device for simulated angular contact ceramic ball bearings invented by patent CN115683627A simulates the rolling of multiple balls to test the fatigue performance of the balls in the bearing. However, the rolling and sliding of the balls in this device are uncertain, so a certain rolling-slip ratio cannot be determined. Summary of the Invention

[0004] The purpose of this invention is to provide a rolling-slip contact friction and wear test device based on a planetary gear train to simulate the friction characteristics of different rolling-slip ratios.

[0005] The technical solution to achieve the purpose of this invention is as follows:

[0006] A rolling-sliding contact friction and wear testing device based on a planetary gear system includes: a central gear, a planetary gear, a gear ring, an upper gear, balls, an inner raceway, an outer raceway, a first motor, a second motor, and a third motor;

[0007] An annular groove is provided between the outer raceway and the inner raceway to mate with the ball, and the groove is interference-fitted with the ball.

[0008] The first motor is connected to the central gear via a central shaft; the inner raceway is coaxially fixed with the central gear.

[0009] The second motor is connected to the upper gear; the outer raceway is provided with outer gear teeth, the gear ring is provided with outer gear teeth and inner gear teeth, and the outer raceway is coaxially fixed with the gear ring; the upper gear meshes with the outer raceway and the outer gear teeth of the gear ring;

[0010] The third motor is connected to the planetary carrier; the planetary carrier is provided with multiple planetary gears at equal intervals along the circumference; the planetary gears mesh with the inner teeth of the central gear and the gear ring, and are fixed with a ball bearing.

[0011] During operation, two of the motors act as the active drive, while the transmission between the central gear and the gear ring forms the driven transmission.

[0012] The significant advantages of this invention compared to existing technologies are:

[0013] (1) In this invention, any two of the three components—the central shaft, the planetary carrier, and the upper transmission shaft—can be selected as input shafts. The three output modes allow two components to act as driving components and one component to act as driven components, resulting in diverse motion forms.

[0014] (2) The present invention can realize the movement of the ball with a fixed rolling ratio. When the pitch circle of the gear used in the present invention is the same as the size of the ball, the ball will roll purely in the inner and outer raceways. When the size of the ball is not equal to the size of the pitch circle of the gear, the ball will roll and slide in a certain proportion. This can simulate the situation of the ball rolling in the upper and lower circular arc grooves, and can simulate the situation of the ball moving in a ball screw or similar mechanical structure. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0016] Figure 2 This is a simplified diagram of the mechanism motion of the present invention.

[0017] Figure 3 This is a side view of the gear structure of the present invention.

[0018] Figure 4 This is a schematic diagram of the ball bearing rotation method of the present invention.

[0019] Figure 5 This is a cross-sectional view of the raceway structure of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Reference Figure 1-5 This embodiment of a rolling and sliding contact friction and wear test device based on a planetary gear system includes a central gear 1, a planetary gear 2, a gear ring 3, an upper gear 4, a ball 10, an outer raceway and an inner raceway, and a first motor 11, a second motor 12 and a third motor 13 fixed by a fixing frame.

[0022] The inner raceway is divided into a left inner raceway 9 and a right inner raceway 8. The inner raceway and the central gear 1 are coaxially fixed. The outer raceway is divided into a left outer raceway 6 and a right outer raceway 5. The outer raceway and the gear ring 3 are fixedly connected.

[0023] In this embodiment, there are 8 planetary gears 2, which are circumferentially and equally spaced on the planet carrier 7, respectively meshing with the central gear 1 and the inner ring gear of the gear ring 3. The planetary gears 2 and the ball bearings 10 are coaxially connected.

[0024] The upper gear 4 meshes with the gear ring 3 and the outer ring gear of the outer raceway. The first motor 11 drives the central gear 1 fixed on the central shaft to rotate, the second motor 12 drives the upper gear 4 to rotate, and the third motor 13 drives the planetary carrier 7 to rotate. The extended shafts of the three motors are respectively connected to the coupling and the torque sensor, and then power is output.

[0025] The diameter of the ball 10 is slightly larger than that of the planetary gear 2. The rolling elements and the annular grooves on the raceway are interference-fitted. The rolling elements of the ball 10 are tangent to the upper and lower circular arc grooves formed by the raceway, thereby applying contact stress load to the ball 10.

[0026] In this implementation, the central gear 1 is fixed to the left inner raceway 9 and the right inner raceway 8. The three parts are fixed on the central shaft, so that the rotational speed of the inner raceway is the same as that of the central gear 1.

[0027] In this embodiment, eight planetary gears 2 are fixed on the planetary gear shafts of the planetary carrier 7. The planetary gears 2 simultaneously mesh with the inner ring gears of the central gear 1 and the gear ring 3. The eight rolling ball bearings 10 are coaxially fixed to the planetary gears 2.

[0028] In this embodiment, the inner and outer rings of the gear ring 3 mesh with the planetary gear 2 and the upper gear 4, respectively. The upper gear 4 transmits motion to the fixedly connected gear ring 3, the left outer raceway 6, and the right outer raceway 5 through a motor-driven coupling and a torque sensor.

[0029] In this implementation example, the outer rings of the left outer raceway 6 and the right outer raceway 5 are gears. The gears on the outer rings of the outer raceways mesh with the upper gear 4. The inner rings are two circular arcs, which are combined to form the upper circular arc groove.

[0030] In this implementation, the outer rings of the left inner raceway 9 and the right inner raceway 8 are two arcs, which combine to form the lower arc groove. The upper and lower arc grooves together form the track for the rolling of the ball.

[0031] In this embodiment, the ball 10 rolls in the arc groove formed by the inner and outer raceways. The diameter of the ball is slightly larger than the diameter of the raceway, thereby achieving an interference fit to apply a certain contact stress load. The amount of interference can be adjusted to adjust the load size, simulating the load during the rolling and sliding process.

[0032] In this embodiment, based on the degrees of freedom of this friction and wear testing device, any two of the first motor 11, the second motor 12, and the third motor 13 can be selected as driving devices, and the remaining one can be used as a driven device.

[0033] The gears used in this implementation are as follows: center gear 1 has 64 teeth, planetary gear 2 has 12 teeth, gear ring 3 has 112 outer ring teeth and 88 inner ring teeth, and upper gear 4 has 28 teeth. The gear module is 2mm for all gears. The diameter D of the arc groove formed by the outer and inner raceways can be adjusted within a reasonable range. The ball diameter is slightly larger than D. When the diameter D of the arc groove formed by the inner and outer raceways is the same as the diameter of the planetary gear (24mm), and the ball diameter is slightly larger than D, the planetary gears perform pure rolling in the planetary gear train. The motion of the balls is pure rolling in all three transmission methods.

[0034] In this implementation example, the first motor 11 outputs a rotational speed of n1 to the central shaft, the second motor 12 outputs a rotational speed of n2 to the gear ring 3, and the third motor 13 outputs a rotational speed of n to the planetary carrier 7. H If the rotational speed of planetary gear 2 is n0, then its speed satisfies equations 1 and 2. For ball 10, its revolution speed is equal to the speed of planet carrier 7, and its rotational speed is equal to the speed of planetary gear 4.

[0035]

[0036]

[0037] In this embodiment, the diameter of the arc groove formed by the inner and outer raceways is D, the diameter of the ball is slightly larger than D, the distance from the central shaft to the pitch circle of the inner ring of the gear ring is D1, and the distance from the central shaft to the pitch circle of the central gear is D2. Then, the rotation distance T of the ball, the sliding distance S1 relative to the inner raceway, and the sliding distance S2 relative to the outer raceway can be calculated, as shown in Equations 3, 4, and 5. The rolling-slip ratios of the ball relative to the outer raceway and the inner raceway are T:S1 and T:S2, respectively. By adjusting different ratios, the ball motion with different rolling-slip ratios can be simulated.

[0038] T = n0 × D × π (Equation 4)

[0039] S1=(n H -n1)×D1×π (Equation 5)

[0040] S2=(n H -n2)×D2×π (Equation 6)

[0041] In this embodiment, when the first motor 11 and the second motor 12 are selected as driving devices, the central shaft drives the inner raceway to rotate, and the upper gear 4 drives the gear ring 3 and the outer raceway to rotate through meshing transmission. The inner ring of the gear ring 3 drives the planetary gear 2 to drive the ball 10 as the driven element.

[0042] In this embodiment, when the second motor 12 and the third motor 13 are selected as driving devices, the upper gear 4 drives the gear ring 3 and the outer raceway to rotate, the third motor 13 drives the planetary carrier 7 to rotate, and the central gear 1 drives the gear ring 3 to drive the inner raceway as a driven member.

[0043] In this embodiment, when the first motor 11 and the third motor 13 are selected as driving devices, the central shaft drives the inner raceway to rotate, the planetary carrier 7 drives the planetary gear 2 to rotate, and the planetary gear 2 drives the gear ring 3 to drive the outer raceway as a driven member.

[0044] With the above three driving methods, any two motors can be selected as driving components, which can increase the flexibility of movement. If one motor fails, the other two can be used for measurement experiments. Different output motors can be flexibly selected to achieve different movement speed ratios.

Claims

1. A rolling-slip contact friction and wear testing device based on a planetary gear train, characterized in that, Includes: center gear, planetary gear, gear ring, upper gear, ball bearings, inner raceway, outer raceway, first motor, second motor, and third motor; An annular groove is provided between the outer raceway and the inner raceway to mate with the ball, and the groove is interference-fitted with the ball. The first motor is connected to the central gear via a central shaft; the inner raceway is coaxially fixed with the central gear. The second motor is connected to the upper gear; the outer raceway is provided with outer gear teeth, the gear ring is provided with outer gear teeth and inner gear teeth, and the outer raceway is coaxially fixed with the gear ring; the upper gear meshes with the outer raceway and the outer gear teeth of the gear ring; The third motor is connected to the planetary carrier; the planetary carrier is provided with multiple planetary gears at equal intervals along the circumference; the planetary gears mesh with the inner teeth of the central gear and the gear ring, and are fixed with a ball bearing. During operation, two of the motors act as the active drive, while the transmission between the central gear and the gear ring forms the driven transmission.

2. The rolling-slip contact friction and wear testing device based on a planetary gear train according to claim 1, characterized in that, By adjusting the rolling slip ratios T:S1 and T:S2 of the balls relative to the outer and inner raceways, the motion of balls with different rolling slip ratios can be simulated. T = n0 × D × π S1=(n H -n1)×D1×π S2=(n H -n2)×D2×π Where T, S1, and S2 are the ball's rotational distance, the ball's sliding distance relative to the inner raceway, and the ball's sliding distance relative to the outer raceway, respectively; D is the diameter of the annular groove, n0 is the planetary gear's rotational speed, and n H n1 is the speed at which the third motor outputs to the planetary carrier, n2 is the speed at which the second motor outputs to the gear ring, D1 is the distance from the central shaft to the pitch circle of the inner ring of the gear ring, and D2 is the distance from the central shaft to the pitch circle of the central gear.

3. The rolling-slip contact friction and wear testing device based on a planetary gear train according to claim 1, characterized in that, The inner raceway includes a left inner raceway and a right inner raceway. The inner rings of the left inner raceway and the right inner raceway are two arcs, which are combined to form an upper arc groove. The outer raceway includes a left outer raceway and a right outer raceway. The outer rings of the left outer raceway and the right outer raceway are arcs, which are combined to form a lower arc groove.

4. The rolling-slip contact friction and wear testing device based on a planetary gear train according to claim 1, characterized in that, The extended shafts of the three motors are respectively connected to couplings and torque sensors for power output.

5. The rolling-slip contact friction and wear testing device based on a planetary gear train according to claim 1, characterized in that, The planetary gears are configured to have eight units.

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