CN113389865A

CN113389865A - Planetary transmission based on magneto-rheological gear shifting

Info

Publication number: CN113389865A
Application number: CN202110633798.3A
Authority: CN
Inventors: 马彪; 王赫; 于亮; 陈漫; 张斌
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2021-09-14

Abstract

The invention discloses a planetary transmission based on magneto-rheological gear shifting, wherein a planet wheel of the planetary transmission is meshed with a sun wheel shaft and a gear ring; the planet carrier is fixedly connected with the planet wheel shaft; a first coil is embedded in the inner wall of the box body, and first magnetorheological fluid is filled between the first coil and the gear ring; a second coil is arranged between the gear ring output sleeve and the box body, and second magnetorheological fluid is filled between the planet carrier output sleeve on the inner peripheral side of the second coil and the gear ring output sleeve; the inner peripheral side of the planet carrier output sleeve is in key connection with a locking sleeve and an output gear sleeve; the locking sleeve is coaxially arranged with the sun wheel shaft; the output gear sleeve is fixedly connected to the outer peripheral side of one end of the locking sleeve, and one end of the output gear sleeve extends out of the box body. The planetary transmission can realize stepless regulation of output torque, does not need a friction pair and a hydraulic control mechanism, can effectively reduce the weight and the volume of the transmission, improves the transmission efficiency, avoids abrasion and impact of parts in the gear shifting process, and improves the reliability and the service life.

Description

Planetary transmission based on magneto-rheological gear shifting

Technical Field

The invention relates to the technical field of vehicle transmission, in particular to a planetary transmission based on magneto-rheological gear shifting.

Background

At present, a two-gear planetary transmission is generally adopted in a transmission system of a high-power electrically-driven tracked vehicle, and the purpose is to expand the torque and rotating speed range of a driving motor and enable the vehicle to obtain better power performance, such as slope climbing, acceleration and highest vehicle speed. In order to realize integrated arrangement and reduce the volume of a transmission device, a planetary transmission with compact structure, large transmission power and coaxial input and output is generally used. In the prior art, a wet multi-plate clutch is mostly adopted in a planetary transmission gear shifting mechanism.

The wet-type multi-plate clutch mainly transfers power by friction torque. The hydraulic oil passage of the clutch is divided into a lubricating oil passage and a control oil passage. In the lubricating oil path, lubricating oil flows into the friction surface through the shaft hole of the driven shaft under the action of pressure so as to lubricate and dissipate heat of the clutch; in the control oil circuit, the electro-hydraulic proportional valve controls lubricating oil to enter an oil cavity of the clutch, and hydraulic pressure is applied to the piston, so that the friction element is pushed to move axially by overcoming the spring force. The clutch completes the engagement process when the gaps between the friction elements are completely lost and slip past each other to zero speed differential.

The wet-type multi-plate clutch is applied to a high-power-density transmission system, has the outstanding problems that a large belt-discharge torque is generated at a high rotating speed, the improvement of the transmission efficiency is restricted, the lubricating and heat-dissipating burden is increased, and a hydraulic control system is required to provide large hydraulic thrust for engagement in the gear shifting process, so that a special oil tank, a hydraulic pump, a pipeline and the like are required to be arranged for the transmission system, the weight and the volume of a transmission device are greatly increased, and the wet-type multi-plate clutch is particularly not suitable for being applied to an electric drive vehicle.

Disclosure of Invention

In view of the above, the present invention provides a planetary transmission based on magnetorheological gear shifting, which can achieve stepless adjustment of output torque, does not need a friction pair and a hydraulic control mechanism, can effectively reduce the weight and volume of the transmission, improves transmission efficiency, avoids abrasion and impact of parts during gear shifting, and improves reliability and service life.

The invention adopts the following specific technical scheme:

a planetary transmission based on magneto-rheological gear shifting comprises a box body, a sun wheel shaft, first magneto-rheological fluid, a gear ring output sleeve, a locking sleeve, an output gear sleeve, a planet carrier output sleeve, a first coil, second magneto-rheological fluid, a second coil, a planet wheel shaft, a gear ring and a planet carrier;

the sun wheel shaft is arranged in the box body, and one end of the sun wheel shaft is connected with an output shaft of the driving motor outside the box body;

the case is supported on the outer peripheral side of the ring gear through a bearing; the ring gear and the planet carrier are rotatably mounted to the sun gear shaft;

the planet wheel is arranged between the sun wheel shaft and the gear ring through the planet wheel shaft and is meshed with the sun wheel shaft and the gear ring; the planet carrier is fixedly connected with the planet wheel shaft; a first coil is embedded in the inner wall of the box body corresponding to the planet wheel, and first magnetorheological fluid is filled between the first coil and the gear ring;

the planet carrier output sleeve is connected to the outer peripheral side of one end of the planet carrier in a key mode;

one end of the gear ring output sleeve is connected with the inner peripheral side of the gear ring; a second coil is arranged between the gear ring output sleeve and the box body, and second magnetorheological fluid is filled between the planet carrier output sleeve on the inner peripheral side of the second coil and the gear ring output sleeve;

the locking sleeve and the output gear sleeve are connected to the inner peripheral side of the planet carrier output sleeve through keys; the locking sleeve is coaxially arranged with the sun wheel shaft;

the output gear sleeve is fixedly connected to the outer peripheral side of one end of the locking sleeve, and one end of the output gear sleeve extends out of the box body.

Furthermore, the gear ring and the gear ring output sleeve are both made of metal materials with high magnetic permeability.

Still further, the planet carrier output sleeve is provided with a plurality of radial grooves on the outer periphery corresponding to the second coil, and the gear ring is provided with a plurality of radial grooves on the outer periphery corresponding to the first coil for increasing the shearing force of the magnetorheological fluid.

Furthermore, an elastic element for vibration isolation is mounted on the outer periphery side of the right box body;

and a plurality of needle bearings are arranged between the planet wheel and the planet wheel shaft.

Furthermore, the box body comprises a left end cover, a left box body, a right box body and a right end cover which are sequentially arranged along the axial direction;

the left box body is fixedly connected with the right box body; the left end cover is fixedly connected to one end, facing the driving motor, of the left box body; the right end cover is fixedly connected to one end, far away from the left box body, of the right box body;

the sun wheel shaft penetrates through the left end cover, and an elastic check ring and a lip-shaped sealing ring are arranged between the sun wheel shaft and the left end cover;

the output gear sleeve penetrates through the right end cover, and a lip-shaped sealing ring is arranged between the output gear sleeve and the right end cover;

the left case and the right case are supported on the outer peripheral side of the ring gear by bearings.

Furthermore, lip-shaped sealing rings are respectively arranged between the gear ring and the left box body and between the right box body and the gear ring output sleeve and are used for sealing two sides of the first magnetorheological fluid;

and lip-shaped sealing rings are arranged between the planet carrier output sleeve and the gear ring output sleeve and between the planet carrier output sleeve and the right box body and are used for sealing two sides of the second magnetorheological fluid.

Further, the ring gear and the planet carrier are supported by the sun gear shaft through bearings and are axially positioned through elastic check rings and shaft sleeves.

Furthermore, an O-shaped sealing ring is clamped between the locking sleeve and the output gear sleeve.

Has the advantages that:

1. the planetary transmission controls the viscosity of the first magnetorheological fluid by adjusting the current in the first coil and controls the viscosity of the second magnetorheological fluid by adjusting the current in the second coil, thereby realizing the stepless adjustment of output torque and the change of transmission ratio, and the magnetorheological gear mechanism is low in energy consumption, easy to control and quick to respond (millisecond level) when the current is introduced and the viscosity of the magnetorheological fluid is converted;

2. the magneto-rheological gear shifting mechanism is adopted to replace a hydraulic control mechanism, the radial size of the transmission is reduced due to the small size of the magneto-rheological gear shifting mechanism, and meanwhile, the weight and the size of the transmission can be greatly reduced without the hydraulic control mechanism;

3. because the magneto-rheological gear shifting mechanism is directly controlled by electric energy, the energy conversion is reduced when the magneto-rheological gear shifting mechanism is applied to an electric drive platform, and the transmission efficiency is improved; the magnetorheological gear shifting mechanism does not need to realize transmission through meshing or friction of a mechanical structure, abrasion and impact of parts in the gear shifting process can be avoided, the reliability of gear shifting is improved, the service life of the gear shifting is prolonged, the gear shifting time is short, gear shifting impact does not exist, the power performance of a vehicle is improved, and the operation comfort level is also improved;

4. through the plurality of radial grooves arranged on the outer peripheral sides of the planet carrier output sleeve and the gear ring, the shearing force of the magnetorheological fluid can be increased by increasing the contact area of the magnetorheological fluid with the planet carrier output sleeve and the gear ring, so that the magnetorheological fluid can generate enough shearing force to control the gear ring to rotate when a magnetic field is applied to the magnetorheological fluid, the shearing force can be increased in the process that the magnetorheological fluid is converted from Newtonian fluid to a solid phase, and the planet carrier output sleeve and the gear ring output sleeve are smoothly connected.

Drawings

FIG. 1 is a schematic structural diagram of a planetary transmission according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of the planetary transmission in fig. 1 when connected with a driving motor.

The magnetorheological fluid damper comprises a driving motor 1, a coupler 2, a sun wheel shaft 3, a flexible retainer 4, a lip-shaped sealing ring 5, a left end cover 6, a shaft sleeve 7, a left box 8, a bearing 9, a right box 10, a first magnetorheological fluid 11, a gear ring output sleeve 12, an elastic element 13, a right end cover 14, a locking sleeve 15, an output gear sleeve 16, a round nut 17, a stop washer 18, a 19-O-shaped sealing ring, a planet carrier output sleeve 20, a second magnetorheological fluid 21, a second coil 22, a baffle ring 23, a planet wheel 24, a first coil 25, a planet wheel shaft 26, a planet wheel shaft 27, a gear ring 28, a needle bearing 29, a planet carrier 30 and a hexagon head bolt.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

The embodiment of the invention provides a planetary transmission based on magneto-rheological gear shifting, the internal structure of the planetary transmission can refer to a graph 1, the assembly structure of the planetary transmission and a driving motor 1 can refer to a graph 2, and the planetary transmission comprises a box body, a sun wheel shaft 3, first magneto-rheological fluid 11, a gear ring output sleeve 12, a locking sleeve 15, an output gear sleeve 16, a planet carrier output sleeve 20, a first coil 25, second magneto-rheological fluid 21, a second coil 22, a planet wheel 24, a planet wheel shaft 26, a gear ring 27 and a planet carrier 29;

the sun wheel shaft 3 is arranged in the box body, and one end of the sun wheel shaft is connected with an output shaft of the driving motor 1 outside the box body; the sun wheel shaft 3 is arranged along the horizontal direction, one end extending out of the box body is connected with an output shaft of the driving motor 1 through the coupler 2 and used as an input shaft of the planetary transmission;

the case is supported on the outer peripheral side of the ring gear 27 through a bearing 9; the ring gear 27 and the carrier 29 are rotatably mounted to the sun gear shaft 3; the gear ring 27 and the planet carrier 29 can be supported on the sun gear shaft 3 through rolling bearings and are axially positioned through the elastic retainer ring 4 and the shaft sleeve 7;

a plurality of planet wheels 24 are arranged between the sun wheel shaft 3 and the gear ring 27 through a planet wheel shaft 26 and are meshed with the sun wheel shaft 3 and the gear ring 27; the planet carrier 29 is fixedly connected with the planet wheel shaft 26; a first coil 25 is embedded in the inner wall of the box body corresponding to the planet wheel 24, and first magnetorheological fluid 11 is filled between the first coil 25 and the gear ring 27;

the planet carrier output sleeve 20 is connected with the outer periphery side of one end of the planet carrier 29 in a key mode; the planet carrier output sleeve 20 can be connected to the planet carrier 29 through a spline; a part of internal splines of the planet carrier output sleeve 20 are meshed with external splines of a planet carrier 29;

one end of the gear ring output sleeve 12 is connected with the inner peripheral side of the gear ring 27; the ring gear output sleeve 12 may be splined to the ring gear 27; a second coil 22 is arranged between the gear ring output sleeve 12 and the box body, and second magnetorheological fluid 21 is filled between the planet carrier output sleeve 20 on the inner peripheral side of the second coil 22 and the gear ring output sleeve 12;

the inner peripheral side of the planet carrier output sleeve 20 is in key connection with a locking sleeve 15 and an output gear sleeve 16; the planet carrier output sleeve 20 is connected to the locking sleeve 15 and the output gear sleeve 16 through splines, and an internal spline of the planet carrier output sleeve 20 is also meshed with external splines of the locking sleeve 15 and the output gear sleeve 16; the locking sleeve 15 is arranged coaxially with the sun gear shaft 3; an O-shaped sealing ring 19 for dust sealing can be clamped between the locking sleeve 15 and the output gear sleeve 16; a round nut 17 and a stop washer 18 are further mounted outside the locking sleeve 15, and the round nut 17 and the stop washer 18 play roles in dust sealing and axial positioning of the output gear sleeve 16;

the output gear sleeve 16 is fixedly connected to the outer peripheral side of one end of the locking sleeve 15, and one end of the output gear sleeve 16 extends out of the box body.

When the planetary transmission is used for an electrically driven vehicle, the driving motor 1 outputs power, the power is transmitted to the sun gear shaft 3 of the planetary transmission through the coupling 2, the driving force is input from the sun gear shaft 3, is output from the planet carrier 29, and is finally transmitted to the wheel-side reduction gear through the planet carrier output sleeve 20 and the output gear sleeve 16. In the use process, after current is introduced to the coils, the coils generate magnetic fields around the coils, and the state of the magnetorheological fluid is changed, so that the connection and the separation of the planet row members are completed, and the change of the transmission ratio is realized. The magnetic rheological liquid is formed by mixing micron-sized magnetized particles in a certain liquid with low magnetic conductivity, the property of the magnetic rheological liquid is similar to that of a Newtonian fluid when a magnetic field is not applied, and the rheological characteristic of the magnetic rheological liquid is changed sharply under the action of a strong magnetic field, so that the magnetic rheological liquid shows the property similar to that of a solid. Compared with the prior art, the planetary transmission can omit a friction pair and a hydraulic control mechanism, effectively reduces the radial size, weight and volume of the transmission, simultaneously directly adopts electric control, can reduce energy conversion when used for electrically driving vehicles, and further improves the transmission efficiency. Because this scheme need not to adopt mechanical device to shift gears, therefore has avoided the wearing and tearing and the impact of the in-process spare part of shifting, has improved reliability and life, and the driving comfort also has certain improvement.

When the output torque is required to be controlled, the first coil 25 is electrified, a strong magnetic field is generated around the first magnetorheological fluid 11, so that the viscosity of the first magnetorheological fluid 11 is changed, the viscosity of the fluid corresponds to the magnetic flux, the torque of the gear ring 27 can be adjusted in a stepless mode within a certain range, and when the torque of the gear ring 27 (braking piece) is controlled, the stepless control of the output torque can be achieved as long as the input torque rotating speed is set. Because the current led into the coil and the viscosity conversion energy consumption of the magnetorheological fluid are low, the control is easy, and the response is rapid (millisecond level), the planetary transmission has relatively excellent torque control capability and can be steplessly adjusted within a certain range. Meanwhile, the planetary transmission has two fixed transmission ratios, and when the external load changes continuously and needs to keep stable output, the fixed transmission ratios are needed. If the vehicle is in a starting stage or a climbing stage and needs a large transmission ratio, a large current is directly introduced into the first coil 25 to enable the first magnetorheological fluid 11 to be rapidly converted to a solid state, the gear ring 27 is completely braked, the transmission ratio is k +1, and k is a characteristic parameter of the planet row;

when a large current is introduced into the second coil 22 to change the flowing state of the second magnetorheological fluid 21, the planet carrier output sleeve 20 is completely jointed with the gear ring output sleeve 12, so that the planet row integrally rotates, the transmission ratio is changed to 1, and the vehicle can run at a higher speed.

In order to improve the control of the coils on the magnetorheological fluid, the gear ring 27 and the gear ring output sleeve 12 can be made of metal materials with high magnetic conductivity, a magnetic field is forced to be concentrated near the coils, for example, when the second coil 22 is electrified, a magnetic path is mainly generated in the gear ring output sleeve 12, the magnetic field mainly acts on the second magnetorheological fluid 21, and the action of the first magnetorheological fluid 11 can be basically isolated.

In order to ensure that the magnetorheological fluid can generate enough shearing force to control the rotation of the ring gear 27 when the magnetic field is applied to the first magnetorheological fluid 11 through the first coil 25, the ring gear 27 is provided with a plurality of radial grooves on the outer peripheral side corresponding to the first coil 25. Similarly, the planet carrier output sleeve 20 is provided with a plurality of radial grooves on the outer peripheral side corresponding to the second coil 22, so that the shearing force can be increased in the process of converting the second magnetorheological fluid 21 from the newton fluid to the solid phase, the planet carrier output sleeve 20 is smoothly jointed with the gear ring output sleeve 12, the planet carrier 29 and the gear ring 27 rotate synchronously, and the whole planetary gear train rotates integrally.

As shown in fig. 1, an elastic member 13 for vibration damping is mounted on the outer peripheral side of the right casing 10; the elastic element 13 can buffer and isolate vibration of the planetary transmission, thereby isolating the adverse effect of the vibration of the chassis of the vehicle body on a power transmission system.

A plurality of needle bearings 28 are mounted between the planetary gear 24 and the planetary gear shaft 26 so that the planetary gear 24 can rotate on its own axis about the planetary gear shaft 26. Retainer rings 23 are respectively mounted on both sides of the needle bearing 28.

On the basis of the various embodiments, the box body is of a split structure and comprises a left end cover 6, a left box body 8, a right box body 10 and a right end cover 14 which are sequentially arranged along the axial direction; the left box body 8 and the right box body 10 can be fixedly connected through bolts; the left case 8 and the right case 10 are supported on the outer peripheral side of the ring gear 27 via a bearing 9; the left end cover 6 is fixedly connected to one end, facing the driving motor 1, of the left box body 8 through a hexagon head bolt 30; the right end cover 14 is fixedly connected to one end of the right box body 10 far away from the left box body 8 through a hexagon head bolt 30; the sun wheel shaft 3 penetrates through the left end cover 6, and an elastic retainer ring 4 and a lip-shaped sealing ring 5 are arranged between the sun wheel shaft 3 and the left end cover 6; the output gear sleeve 16 penetrates through the right end cover 14, and a lip-shaped sealing ring 5 is installed between the output gear sleeve 16 and the right end cover 14.

The box body adopts a split structure, and has the characteristics of convenient installation and easy processing; due to the circlip 4 and the lip seal 5 which are installed between the sun gear shaft 3 and the left end cover 6, and the lip seal 5 which is installed between the output gear sleeve 16 and the right end cover 14, the lip seal 5 has a good dynamic sealing effect, and thus, a function of dust sealing can be performed on the transmission.

In order to provide a good sealing effect for the magnetorheological fluid and restrict the flowing space of the magnetorheological fluid, as shown in the structure of fig. 1, lip-shaped sealing rings 5 are respectively arranged between the gear ring 27 and the left box body 8 and between the right box body 10 and the gear ring output sleeve 12 and are used for sealing two sides of the first magnetorheological fluid 11; lip-shaped sealing rings 5 are arranged between the planet carrier output sleeve 20 and the gear ring output sleeve 12 and between the planet carrier output sleeve and the right box body 10, and are used for sealing two sides of the second magnetorheological fluid 21.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A planetary transmission based on magneto-rheological gear shifting is characterized by comprising a box body, a sun wheel shaft (3), first magneto-rheological fluid (11), a gear ring output sleeve (12), a locking sleeve (15), an output gear sleeve (16), a planet carrier output sleeve (20), a first coil (25), second magneto-rheological fluid (21), a second coil (22), a planet wheel (24), a planet wheel shaft (26), a gear ring (27) and a planet carrier (29);

the sun wheel shaft (3) is arranged in the box body, and one end of the sun wheel shaft is connected with an output shaft of the driving motor (1) outside the box body (3);

the case is supported on the outer peripheral side of the ring gear (27) through a bearing (9); the ring gear (27) and the planet carrier (29) are rotatably mounted to the sun gear shaft (3);

the planet wheels (24) are arranged between the sun wheel shaft (3) and the ring gear (27) through the planet wheel shaft (26) and are meshed with the sun wheel shaft (3) and the ring gear (27); the planet carrier (29) is fixedly connected with the planet wheel shaft (26); a first coil (25) is embedded in the inner wall of the box body corresponding to the planet wheel (24), and a first magnetorheological fluid (11) is filled between the first coil (25) and the gear ring (27);

the planet carrier output sleeve (20) is connected with the outer peripheral side of one end of the planet carrier (29) in a key mode;

one end of the gear ring output sleeve (12) is connected with the inner peripheral side of the gear ring (27) in a key mode; a second coil (22) is arranged between the gear ring output sleeve (12) and the box body, and second magnetorheological fluid (21) is filled between the planet carrier output sleeve (20) on the inner peripheral side of the second coil (22) and the gear ring output sleeve (12);

the inner peripheral side of the planet carrier output sleeve (20) is in keyed connection with the locking sleeve (15) and the output gear sleeve (16); the locking sleeve (15) and the sun wheel shaft (3) are coaxially arranged;

the output gear sleeve (16) is fixedly connected to the outer peripheral side of one end of the locking sleeve (15), and one end of the output gear sleeve (16) extends out of the box body.

2. The planetary transmission as in claim 1, wherein the ring gear (27) and the ring gear output sleeve (12) are both made of a high magnetic permeability metallic material.

3. The planetary transmission as claimed in claim 1, characterized in that the carrier output sleeve (20) is provided with a plurality of radial grooves on an outer peripheral side corresponding to the second coils (22);

the ring gear (27) is provided with a plurality of radial grooves on the outer peripheral side corresponding to the first coil (25).

4. The planetary transmission according to claim 1, wherein an elastic member (13) for vibration isolation is mounted on an outer peripheral side of the right case (10);

a plurality of needle bearings (28) are arranged between the planet wheel (24) and the planet wheel shaft (26).

5. The planetary transmission as claimed in any one of claims 1 to 4, wherein the case includes a left cover (6), a left case (8), a right case (10), and a right cover (14) arranged in this order in the axial direction;

the left box body (8) is fixedly connected with the right box body (10); the left end cover (6) is fixedly connected to one end, facing the driving motor (1), of the left box body (8); the right end cover (14) is fixedly connected to one end, far away from the left box body (8), of the right box body (10);

the sun wheel shaft (3) penetrates through the left end cover (6), and an elastic check ring (4) and a lip-shaped sealing ring (5) are arranged between the sun wheel shaft (3) and the left end cover (6);

the output gear sleeve (16) penetrates through the right end cover (14), and a lip-shaped sealing ring (5) is arranged between the output gear sleeve (16) and the right end cover (14);

the left and right cases are supported on the outer peripheral side of the ring gear (27) by a bearing (9).

6. The planetary transmission according to any one of claims 1 to 4, characterized in that lip seals are installed between the ring gear (27) and the left case (8) and between the right case (10) and the ring gear output sleeve (12) for sealing both sides of the first magnetorheological fluid (11);

and lip-shaped sealing rings are arranged between the planet carrier output sleeve (20) and the gear ring output sleeve (12) and between the right box body (10) and are used for sealing two sides of the second magnetorheological fluid (21).

7. The planetary transmission according to any of claims 1-4, characterized in that the ring gear (27) and the planet carrier (29) are both supported by bearings on the sun gear shaft (3) and are axially positioned by means of circlips and bushings.

8. The planetary transmission according to any one of claims 1 to 4, wherein an O-ring seal is interposed between the lock sleeve (15) and the output sleeve (16).