DEVICE FOR TESTING NEEDLE ROLLER BEARING OF PLANET GEAR SET AND METHOD THEREOF

Abstract

A device for testing a needle roller bearing of a planet gear set consists of two identical helical planet gear sets, a piston, an end cover, a spindle, and can simulate the actual operating condition of a needle roller bearing of the planet gear set; the rotating speed difference between an inner raceway and an outer raceway of the needle roller bearing is determined by adjusting the rotating speed of a sun gear and a planet carrier; the load on the needle roller bearing includes a centrifugal load and a radial load, and the centrifugal acceleration and the centrifugal load are determined by adjusting the rotating speed of the planet carrier; a method of determining the radial load by adjusting the hydraulic pressure difference of hydraulic chambers at both ends of the piston, generating a tangential force to load the planet gear, and balancing the radial load of the bearing.

Claims

1. A device for testing a needle roller bearing of a planet gear set, comprising a housing (13), a first planet gear set (1), a second planet gear set (2), a piston (10), an end cover (9), a spindle (3), a test needle roller bearing (12), a first motor and a second motor, wherein all gears of the first planet gear set (1) and the second planet gear set (2) are helical teeth; wherein a sun gear (5) of the first planet gear set is fixedly connected with the spindle (3), wherein the piston (10) is sleeved on the spindle (3) and is capable of moving along the axial direction of the spindle (3), wherein the piston (10) is connected with the sun gear (5) of the first planet gear set through splines, wherein a sun gear (8) of the second planet gear set is fixedly connected with the piston (10), wherein the end cover (9) is fixedly connected with the spindle (3), wherein a first hydraulic chamber (15) is formed between one end of the piston (10) and the end cover (9), wherein a second hydraulic chamber (16) is formed between another end of the piston and the spindle, wherein the first planet gear set (1) and the second planet gear set (2) share a gear ring (7) of the planet gear set and a planet carrier (4) of the planet gear set, wherein the test needle roller bearings (12) of the planet gear (6) of the first planet gear set and the planet gear (11) of the second planet gear set are both provided on the planet shaft of the planet carrier (4) of the planet gear set, and wherein the planet gear (6) of the first planet gear set and the planet gear (11) of the second planet gear set are not coaxial; wherein the first motor and the second motor are connected with the planet carrier (4) of the planet gear set and the spindle (3), respectively.

2. The device for testing a needle roller bearing of a planet gear set according to claim 1, wherein geometric parameters of the first planet gear set (1) and the second planet gear set (2) are the same.

3. The device for testing a needle roller bearing of a planet gear set according to claim 1, wherein the housing (13) further comprising a housing cover (14).

4. A testing method based on the device for testing a needle roller bearing of a planet gear set according to any one of claim 1, wherein the centrifugal acceleration a.sub.a of a test needle roller bearing (12) in the actual operating condition is simulated by adjusting the rotating speed n.sub.1 of a first motor connected with the planet carrier (4) of the planet gear set: $n_{1} = \frac{1}{2 π .Math. i_{1}} \sqrt{\frac{a_{a}}{r_{c}}}$ where r.sub.c is the radius of the planet carrier of the planet gear set, and i.sub.1 is the transmission ratio of the first motor to the planet carrier (4) of the planet gear set.

5. The testing method according to claim 4, wherein the rotating speed difference Δn between an inner raceway and an outer raceway of the test needle roller bearing (12) in the actual operating condition is simulated by adjusting the rotating speed n.sub.2 of a second motor connected with the spindle (3): $n_{2} = \frac{n_{c} - \frac{d_{p}}{d_{s}} Δ n}{i_{2}} = \frac{i_{1} n_{1} - \frac{d_{p}}{d_{s}} Δ n}{i_{2}}$ where n.sub.c is the rotating speed of the planet carrier of the planet gear set, d.sub.s and d.sub.p are the pitch diameters of the sun gear of the planet gear set and the planet gear of the planet gear set, respectively, and i.sub.2 is the transmission ratio of the second motor to the spindle (3).

6. The testing method according to claim 4, wherein the torque difference between the planet carrier (4) of the planet gear set and the spindle (3) is supplemented by adjusting the first motor torque T.sub.1 and the second motor torque T.sub.2:
T.sub.1=i.sub.1T.sub.s[1−(1−ξ.sub.s-p).sup.2(1−ξ.sub.r-p).sup.2]
T.sub.2=−i.sub.2T.sub.s[1−(1−ξ.sub.s-p).sup.2(1−ξ.sub.r-p).sup.2] where T.sub.s is the torque theoretically transmitted by the sun gear of the planet gear set, ξ.sub.s-p is the torque transmission efficiency between the sun gear of the planet gear set and the planet gear, and ξ.sub.r-p is the torque transmission efficiency between the planet gear of the planet gear set and a gear ring.

7. The testing method according to claim 5, wherein the total load F of the test needle roller bearing (12) in the actual operating condition is simulated by adjusting the mass of the planet gear of the planet gear set and the hydraulic pressure of the hydraulic chambers at both ends of the piston (10), and the total load F further comprising the centrifugal load and the radial load applied by the planet gear, wherein: (1) if the centrifugal load is greater than or equal to the required total load F, adjusting the hydraulic pressure of the hydraulic chambers at both ends of the piston (10) to meet the relationship:
P.sub.1A.sub.1−P.sub.2A.sub.2=0 where A.sub.1 and A.sub.2 are the effective hydraulic action areas of the first hydraulic chamber (15) and the second hydraulic chamber (16), respectively, and P.sub.1 and P.sub.2 are the hydraulic pressures in the first hydraulic chamber (15) and the second hydraulic chamber (16), respectively; adjusting the mass m.sub.p of the planet gear of the planet gear set as follows: $m_{p} = \frac{F}{a_{a}}$ (2) if the centrifugal load is less than the required total load F, adjusting the hydraulic pressure of the hydraulic chambers at both ends of the piston (10) to meet the relationship: $P_{1} A_{1} - P_{2} A_{2} = \frac{N \tan β}{2} \sqrt{F^{2} - {(m_{p} a_{a})}^{2}}$ where A.sub.1 and A.sub.2 are the effective hydraulic action areas of the first hydraulic chamber (15) and the second hydraulic chamber (16), respectively, P.sub.1 and P.sub.2 are the hydraulic pressures in the first hydraulic chamber (15) and the second hydraulic chamber (16), respectively, N is the number of planet gears, and β is the helical angle; keeping the mass of the planet gear of the planet gear set unchanged.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to explain the specific embodiment of the present disclosure or the technical scheme in the prior art more clearly, the drawings needed in the description of the specific embodiment or the prior art will be briefly introduced hereinafter. Obviously, the drawings in the following description are the implementation process and details of the present disclosure. For those skilled in the art, other drawings can be obtained according to these drawings without paying any creative labor.

[0029] FIG. 1 is a schematic structural diagram of a device for testing a needle roller bearing of a planet gear set according to the present disclosure.

[0030] FIG. 2 is a schematic structural diagram of a device for testing a needle roller bearing of a planet gear set according to the present disclosure.

[0031] FIG. 3 is a stress analysis diagram of a planet gear set of a device for testing a needle roller bearing of a planet gear set according to the present disclosure.

[0032] FIG. 4 is a stress analysis diagram of a meshing point of a first planet gear set of a device for testing a needle roller bearing of a planet gear set according to the present disclosure.

[0033] FIG. 5 is a stress analysis diagram of a meshing point of a second planet gear set of a device for testing a needle roller bearing of a planet gear set according to the present disclosure.

DESCRIPTION OF REFERENCE NUMBERS

[0034] 1-first planet gear set, 2-second planet gear set, 3-spindle, 4-planet carrier of a common planet gear set, 5-sun gear of a first planet gear set, 6-planet gear of a first planet gear set, 7-gear ring of a planet gear set, 8-sun gear of a second planet gear set, 9-end cover, 10-piston, 11-planet gear of a second planet gear set, 12-test needle roller bearing, 13-housing, 14-housing cover, 15-first hydraulic chamber, 16-second hydraulic chamber.

DETAILED DESCRIPTION

[0035] In order to understand the above objects, features and advantages of the present disclosure more clearly, the present disclosure will be described in further detail below with reference to the drawings and detailed description. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0036] In the following description, many specific details are set forth in order to fully understand the present disclosure. However, the present disclosure can be implemented in other ways different from those described here. Therefore, the scope of protection of the present disclosure is not limited by the specific embodiments disclosed hereinafter.

[0037] In order to facilitate the understanding of the above-mentioned technical scheme of the present disclosure, the above-mentioned technical scheme of the present disclosure will be explained in detail by specific embodiments hereinafter.

[0038] As shown in FIG. 1-2, the present disclosure provides a device for testing a needle roller bearing of a planet gear set, comprising a housing 13, a first planet gear set 1, a second planet gear set 2, a piston 10, an end cover 9, a spindle 3, and a test needle roller bearing 12, wherein the geometric parameters of the first planet gear set 1 and the second planet gear set 2 are the same, and all gears are helical teeth. The connection method is as follows: a sun gear 5 of the first planet gear set is fixedly connected with the spindle 3, the piston 10 is sleeved on the spindle 3 and is movable along the axial direction of the spindle 3, and a sun gear 8 of the second planet gear set is fixedly connected with the piston 10; the piston 10 is connected with the sun gear 5 of the first planet gear set through splines; the end cover 9 is fixedly connected with the spindle 3; the first planet gear set 1 and the second planet gear set 2 share a gear ring 7 of the planet gear set; the first planet gear set 1 and the second planet gear set 2 share a planet carrier 4 of the planet gear set, and three planet gear of the first planet gear sets 6 and three planet gear of the second planet gear sets 11 are circumferentially uniformly distributed on six planet shafts of the planet carrier of a common planet gear set 4 via the test needle roller bearing. The power of the testing device is input through the planet carrier and the spindle 3, and the power is provided by the motor.

[0039] A first hydraulic chamber 15 is formed between one end of the piston 10 and the end cover 9, and a second hydraulic chamber 16 is formed between the other end of the piston and the spindle. Moreover, a stable hydraulic pressure difference can be maintained. The piston 10 is subjected to axial hydraulic pressure.

[0040] Since the geometric parameters of the first planet gear set 1 and the second planet gear set 2 are the same, and there is no power output, the first planet gear set and the second planet gear set can realize a closed cycle of power flow, and the motor only needs to supplement the torque and power lost by the testing device, thus reducing the energy loss. Assuming that the power transmission loss between the sun gear and the planet gear of the testing device is 1.5%, the power transmission loss between the planet gear and the gear ring is 1.0%, the power demand of the motor connected with the spindle 3 can be reduced by 95% and the power demand of the motor connected with the planet carrier can be reduced by 98%, regardless of the oil loss, the power transmission loss between the spindle 3, the planet carrier and the motor, etc.

[0041] The testing device can simulate and test the actual operating condition of the test needle roller bearing of the planet gear set by adjusting the motor speed, the torque and the hydraulic pressure difference between both ends of the piston 10, including the performance in three aspects: the rotating speed difference between the inner raceway and the outer raceway, the centrifugal acceleration and the total load, in which the total load comprises a centrifugal load and a radial load. The implementation principle thereof is as follows:

[0042] 1. Rotating speed difference between the inner raceway and the outer raceway

[0043] The method for testing the rotating speed difference Δn between the inner raceway and the outer raceway of the needle roller bearing is as follows: the rotating speed ns of the sun gear of two planet gear sets is the same as that of the spindle 3, and is adjusted by the second motor; the rotating speed n.sub.c of the planet carrier of two planet gear sets is adjusted by the first motor; the autorotation speed n.sub.p of the planet gear is defined by the following formula:

[00005] $n_{p} = - \frac{d_{s}}{d_{p}} (n_{s} - n_{c})$

[0044] where d.sub.s and d.sub.p are the pitch diameters of the sun gear and the planet gear, respectively.

[0045] The rotating speed difference Δn between the inner raceway and the outer raceway of the test needle roller bearing is obtained by the following formula:

[00006] $Δ n = n_{p} = - \frac{d_{s}}{d_{p}} (n_{s} - n_{c})$

[0046] 2. Centrifugal Acceleration

[0047] The method for testing the centrifugal acceleration of the needle roller bearing is as follows: the rotating speed n.sub.c of the planet carrier of the planet gear set is determined by the first motor, and the centrifugal acceleration a.sub.a of the test needle roller bearing is obtained by the following formula:

a.sub.a=(2πn.sub.c).sup.2r.sub.c

[0048] where r.sub.c is the radius of the planet carrier.

[0049] 3. Total Load

[0050] The total load F of the test needle roller bearing comprises the centrifugal load and the radial load applied by the planet gear, and the relationship thereof is as follows:

F.sub.1=√{square root over (F.sub.c.sup.2+F.sub.r1.sup.2)}

F.sub.2=√{square root over (F.sub.c.sup.2+F.sub.r2.sup.2)}

[0051] where F.sub.c is the centrifugal load applied to the test needle roller bearing by the planet gear, and F.sub.r1 and F.sub.r2 are the radial loads applied to the test needle roller bearing by the planet gears of two planet gear sets, which are equal in magnitude and opposite in direction.

[0052] (1) Centrifugal Load

[0053] The centrifugal load F.sub.c applied to the test needle roller bearing by the planet gear is obtained by the following formula:

F.sub.c=m.sub.pa.sub.a

[0054] where m.sub.p is the mass of the planet gear.

[0055] (2) Radial Load

[0056] FIG. 3 is a stress analysis diagram of two planet gear sets. The radial load applied to the test needle roller bearing by the planet gear is determined by the hydraulic pressure of the hydraulic chambers at both ends of the piston. The specific method is as follows.

[0057] The hydraulic pressure on the piston is as follows:

F.sub.ap=P.sub.1A.sub.1−P.sub.2A.sub.2

where the effective hydraulic action areas of the first hydraulic chamber and the second hydraulic chamber are A.sub.1 and A.sub.2, respectively, and the hydraulic pressures thereof are P.sub.1 and P.sub.2, respectively. Because the piston is fixedly connected with the sun gear of the second planet gear set, the hydraulic pressure F.sub.ap on the piston is transmitted to the sun gear of the second planet gear set, and the axial force Fat on the sun gear of the second planet gear set is as follows:

F.sub.a2=F.sub.ap

[0058] The hydraulic pressure on the end cover is as follows:

F.sub.1=−P.sub.1A.sub.1

[0059] The hydraulic pressure on the spindle is as follows:

F.sub.a=P.sub.2A.sub.2

[0060] Because the end cover is fixedly connected with the spindle, the axial force of the spindle 3 is as follows:

F.sub.as=P.sub.2A.sub.2−P.sub.1A.sub.1=−F.sub.ap

[0061] The spindle is fixedly connected with the sun gear of the first planet gear set, and the hydraulic pressure F.sub.as on the spindle is transmitted to the sun gear of the first planet gear set, so that the axial force F.sub.a1 of the sun gear of the first planet gear set is as follows:

F.sub.a1=−F.sub.ap

[0062] FIG. 4 and FIG. 5 are stress analysis diagrams of meshing points of a first planet gear set and a second planet gear set, respectively. In order to keep the stress of the sun gear balanced, the meshing force between the sun gear and the planet gear is equal to the axial force of the sun gear, and the tangential forces of the planet gears of the first planet gear set and the second planet gear set are as follows:

[00007] $F_{t 1} = \frac{F_{a 1}}{N \tan β} = - \frac{F_{a 2}}{N \tan β} = - F_{t 2}$

[0063] The radial load applied to the test needle roller bearing by the planet gears of the first planet gear set and the second planet gear set is as follows:

F.sub.r1=2F.sub.t1=−2F.sub.t2=F.sub.r2

[0064] so that:

[00008] $F_{r 1} = 2 \frac{P_{2} A_{2} - P_{1} A_{1}}{N \tan β} = - F_{r 2}$

[0065] where N is the number of planet gears, and β is the helical angle.

[0066] According to the required radial load and the effective hydraulic action area, the hydraulic pressures P.sub.1 and P.sub.2 of the hydraulic chambers at both ends of the piston are determined.

[0067] The testing method using the testing device of the present disclosure is as follows.

[0068] S1, the rotating speed of the motor connected with the planet carrier is adjusted.

[0069] According to the centrifugal acceleration a.sub.a required for the test needle roller bearing, the rotating speed n.sub.c of the planet carrier of the planet gear set is determined, and then the rotating speed n.sub.1 of the first motor is adjusted as follows:

[00009] $n_{1} = \frac{1}{2 π .Math. i_{1}} \sqrt{\frac{a_{a}}{r_{c}}}$

[0070] S2, the rotating speed of the motor connected with the spindle is adjusted.

[0071] According to the rotating speed difference Δn between the ring inner and the outer raceway required for the test needle roller bearing, the rotating speed ns of the spindle is determined, and then the rotating speed n.sub.2 of the second motor is adjusted as follows:

[00010] $n_{2} = \frac{n_{c} - \frac{d_{p}}{d_{s}} Δ n}{i_{2}} = \frac{i_{1} n_{1} - \frac{d_{p}}{d_{s}} Δ n}{i_{2}}$

[0072] S3, the first motor torque T.sub.1 and the second motor torque T.sub.2 are adjusted.

[0073] According to the torque difference between the planet carrier of the planet gear set and the spindle 3, the first motor torque T.sub.1 and the second motor torque T.sub.2 are adjusted:

T.sub.1=i.sub.1T.sub.s[1−(1−ξ.sub.s-p).sup.2(1−ξ.sub.r-p).sup.2]

T.sub.2=−i.sub.2T.sub.s[1−(1−ξ.sub.s-p).sup.2(1−ξ.sub.r-p).sup.2]

[0074] where T.sub.s is the torque theoretically transmitted by the sun gear of the planet gear set, ξ.sub.s-p is the torque transmission efficiency between the sun gear of the planet gear set and the planet gear, and ξ.sub.r-p is the torque transmission efficiency between the planet gear of the planet gear set and a gear ring.

[0075] S4, the mass of the planet gear and the hydraulic pressure of the hydraulic chamber at both ends of the piston are adjusted.

[0076] According to the total load F required for test needle roller bearing, the mass of the planet gear and the hydraulic pressure of the hydraulic chamber at both ends of the piston are adjusted.

[0077] In the operation of the testing device, there are the following two situations.

[0078] (1) if the centrifugal load is greater than or equal to the required total load F(F.sub.1, F.sub.2), the hydraulic pressure of the hydraulic chambers at both ends of the piston should be adjusted to meet the relationship:

P.sub.1A.sub.1−P.sub.2A.sub.2=0

[0079] At the same time, the mass of the planet gear is adjusted as follows:

[00011] $m_{p} = \frac{F}{a_{a}}$

[0080] (2) if the centrifugal load is less than the required total load F, the hydraulic pressure of the hydraulic chambers at both ends of the piston should be adjusted to meet the relationship:

[00012] $P_{1} A_{1} - P_{2} A_{2} = \frac{N \tan β}{2} \sqrt{F^{2} - {(m_{p} a_{a})}^{2}}$

[0081] At the same time, the mass of the planet gear remains unchanged.

[0082] The above-mentioned embodiments are only preferred embodiments of the present disclosure, and do not limit the present disclosure in any form. All of the possible changes, modifications or amendments made to the technical scheme of the present disclosure by those skilled in the art using the technical content disclosed above without departing from the scope of the technical scheme of the present disclosure are equivalent embodiments of the present disclosure. Therefore, all equivalent changes made according to the idea of the present disclosure without departing from the content of the technical scheme of the present disclosure shall be covered in the scope of protection of the present disclosure.

DEVICE FOR TESTING NEEDLE ROLLER BEARING OF PLANET GEAR SET AND METHOD THEREOF

Inventors

Cpc classification

Classification Explorer

G01M13/04

PHYSICS

Classification Explorer

G01M13/021

PHYSICS

Classification Explorer

F16H57/082

MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

Classification Explorer

F16H2057/085

MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

International classification

Classification Explorer

G01M13/04

PHYSICS

Classification Explorer

F16H57/08

MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

Abstract

Claims

Description