A housing-rotating cycloid motor with an oil draining function

Abstract

The present invention relates to the field of cycloidal hydraulic motors, and particularly to a housing-rotating cycloidal motor with an oil-draining function, which includes a rotating part and a fixed part. The interior of the rotating part is cooperatively connected with the fixed part, and a hydraulic shaft seal is provided at the joint between the fixed part and the rotating part. It also includes an oil-draining cavity, which is arranged on the outer peripheral side of the joint between the fixed part and the rotating part. The oil-draining cavity is communicated with the joint between the fixed part and the rotating part. The fixed part is also provided with an oil-draining port, and the oil-draining port is communicated with the oil-draining cavity through an oil-draining oil path. By adding the design of a flow-dividing piece and a compensation disc, the problem that the same type of shaft-rotating motor cannot add an oil-draining function is solved. After adding the oil-draining cavity, the pressure on the shaft seal of the motor can be reduced, enabling the motor to use ordinary hydraulic shaft seals, reducing the manufacturing cost, prolonging the service life of the hydraulic shaft seal, and reducing the maintenance cost. Moreover, the housing-rotating type can effectively shorten the axial length of the motor, facilitating its application in the walking drive of small machinery.

Description

Technical Field

[0001] The present invention belongs to the field of cycloid hydraulic motors, and particularly relates to a housing-rotating cycloid motor with an oil draining function. Background Art

[0002] Cycloid hydraulic motors are commonly used hydraulic drive devices, which are low-speed high-torque motors. They have the advantages of small size, high unit power density, high efficiency, wide speed range, etc., and are widely used. With the improvement of the development level of industry and agriculture, their applications will be more extensive.

[0003] The existing cycloid hydraulic motors with output shafts have relatively long axial dimensions. When used as traveling motors in small-sized machines such as mini excavators, the long axial dimensions prevent the motors from being fully installed within the track width and will exceed the track protection range. When the machine is traveling, the harsh ground conditions can easily damage the motors.

[0004] Using a housing-rotating cycloid motor can eliminate the output shaft, thus shortening the axial dimension. Due to structural limitations, the existing shaft-rotating cycloid motors cannot add an oil drain passage. When a cycloid motor without an oil draining function is in use, the motor must be equipped with a hydraulic shaft seal that can withstand high pressure, which is expensive and very easy to damage. Once the hydraulic shaft seal is damaged, the motor needs to be disassembled for replacement, resulting in a significant increase in the maintenance frequency and cost. Summary of the Invention

[0005] In view of the above problems, the present invention provides a housing-rotating cycloid motor with an oil draining function. By adding the design of a shunt plate and a compensation disk, the problem that the same type of shaft-rotating motor cannot add an oil draining function is solved. After adding an oil drain cavity, the pressure on the motor shaft seal treatment can be reduced, enabling the motor to use ordinary hydraulic shaft seals, reducing the manufacturing cost, prolonging the service life of the hydraulic shaft seal, and reducing the maintenance cost. Moreover, using the housing-rotating type can effectively shorten the axial length of the motor, facilitating its application in the traveling drive of small machinery.

[0006] The solution provided by the present invention is as follows:

[0007] A housing-rotating cycloid motor with an oil draining function includes a rotating part and a fixed part. One end of the rotating part is sleeved outside the fixed part and is rotatably connected to the fixed part. The inside of the rotating part is cooperatively connected with the fixed part, and a hydraulic shaft seal is provided at the cooperative connection. The present invention uses a housing-rotating cycloid motor. During operation, power is output by the rotation of the rotating part, and the hydraulic oil seal is used to provide sealing during rotation. When the motor is operating, due to the relative rotation between the rotating part and the fixed part, hydraulic oil will leak from the cooperative connection between the rotating part and the fixed part into the motor oil drain cavity, and the hydraulic shaft seal seals the leaked hydraulic oil to prevent leakage outside the motor. Therefore, the hydraulic shaft seal needs to withstand the pressure of the hydraulic oil in the oil drain cavity.

[0008] It further includes a spline shaft, one end of the spline shaft extends into the interior of the rotating part and is connected to the rotating part, and the other end extends into the interior of the fixed part and is connected to the fixed part.

[0009] Specifically, the rotating part includes a front cover, a balance disk, an outer rotor, a flow distribution disk, and a hub that are connected in sequence. The front cover, balance disk, outer rotor, flow distribution disk, and hub can all rotate synchronously around the central axis. The structures of the front cover, balance disk, outer rotor, and flow distribution disk in the present invention are the working structures of a prior art hydraulic cycloid motor. It also includes an inner rotor, the inner rotor is arranged inside the outer rotor, and the inner rotor cooperates with the outer rotor, balance disk, and flow distribution disk to form a working oil chamber. The working oil chamber is separated into several oil chambers by the inner rotor and the outer rotor. Part of them are high-pressure oil chambers and part of them are low-pressure oil chambers. The pressure difference drives the inner rotor to revolve inside the outer rotor. The revolution of the inner rotor causes the high-pressure oil chamber and the low-pressure oil chamber to alternate in sequence, generating continuous power. The hydraulic oil flows into the working oil chamber after being distributed by the flow distribution disk to provide hydraulic power.

[0010] Different from an ordinary cycloid motor, when the inner rotor of an ordinary cycloid motor revolves inside the outer rotor (this component is the stator in an ordinary cycloid motor), it will generate self-rotation. The rotation is transmitted to the spline shaft connected to the inner rotor, and the spline shaft drives the output shaft for power output. The housing-rotating type cycloid motor in the present invention is driven by hydraulic power to rotate the overall rotating part. The inner rotor only generates revolution during operation and does not perform self-rotation, that is, the spline shaft connected to the inner rotor does not perform power output. The hub in the rotating part is sleeved on the outer peripheral side of the fixed part through a bearing, so that the entire rotating part can rotate, and the power is directly output by the rotating part without an output shaft, effectively reducing the axial length. The driven tire or track can be directly installed on the hub for driving.

[0011] The fixed part includes a housing, a central oil chamber is arranged inside the housing, the central oil chamber is communicated with the working oil chamber through a flow distribution disk, and it further includes a spline shaft sleeve. The spline shaft sleeve is arranged inside the central oil chamber. One end of the spline shaft is in fit connection with the spline shaft sleeve. The spline shaft sleeve only serves as a connecting part of the spline shaft and does not perform power output.

[0012] As described above, the hub is installed on the outer side of the housing through a bearing and is rotatably connected to the housing.

[0013] The housing is provided with a first oil port and a second oil port. The first oil port is communicated with the working oil cavity through a distribution disc, and the second oil port is communicated with the central oil cavity. The first oil port and the second oil port are the power connection ports of the cycloid motor and are connected to the hydraulic oil source. One of the two oil ports is connected to the inlet port and the other is connected to the return port, and the output direction of the hydraulic oil source can be adjusted for alternate change. The oil port communicated with the inlet port is the high-pressure oil port. The high-pressure oil enters the high-pressure cavity in the working oil cavity after distribution, and flows out from the return port through the channel after doing work, completing the circulation work of the hydraulic oil.

[0014] After installation, there is relative rotation between the distribution disc and the housing. The hydraulic oil at the connection between the distribution hole and the first oil port will leak out from the hydraulic balance gap between the tightly attached distribution disc and the compensation disc installed on the housing. The purpose of the hydraulic shaft seal is to seal the leaked hydraulic oil. In the existing axial-rotating motor products on the market, when the central oil cavity is the high-pressure cavity, the hydraulic oil seal is subjected to the high pressure output by the hydraulic oil source. Therefore, in the prior art, a specific hydraulic shaft seal that can withstand high pressure needs to be selected for the hydraulic shaft seal. This kind of hydraulic shaft seal is expensive, resulting in a significant increase in the cost of the entire motor.

[0015] To solve this problem, the present invention designs an oil drain cavity. The position of the oil drain cavity is on the outer peripheral side of the mating contact surface of the rotating part and the fixed part, that is, on the housing on the outer peripheral side of the contact surface between the distribution disc and the housing. The oil drain cavity is communicated with the contact surface between the distribution disc and the compensation disc installed on the housing. Due to the relative movement of the mating contact surface of the rotating part and the fixed part, the high-pressure oil flows into the oil drain cavity through the gap of this mating contact surface, and then flows out from the oil drain port through the oil drain oil path connected to the oil drain cavity, reducing the pressure in the oil drain cavity, so that the hydraulic oil seal does not need to bear too high pressure, and thus a common hydraulic oil seal can be selected during assembly, reducing the manufacturing cost.

[0016] In order to structurally implement the structure of the oil discharge cavity, the present invention provides a compensation disk. The compensation disk is arranged in the central oil cavity. The spline shaft passes through the compensation disk. One end of the compensation disk is connected to the housing, and the other end is in contact connection with the distribution disk. A number of compensation oil through holes are provided on the compensation disk. One end of the compensation oil through hole is communicated with the first oil port, and the other end is communicated with the working oil cavity through the distribution hole of the distribution disk. At the same time, on one side of the multi-piece composite distribution disk in the prior art, the present invention's distribution disk is increased with a flow splitting piece. One side of the flow splitting piece is connected to the composite distribution disk, and a convex end is provided at the center of the other side. The convex end extends into the housing and is in contact connection with the compensation disk. A flow splitting oil through hole is provided on the flow splitting piece. One end of the flow splitting oil through hole is communicated with the distribution hole, and the other end is communicated with the compensation oil through hole. The hydraulic shaft seal is arranged outside the convex end. The cooperation of the compensation oil through hole and the flow splitting oil through hole can ensure the smooth flow of hydraulic oil during rotation. At the same time, through the design of the convex end of the flow splitting piece, the position of the hydraulic shaft seal is moved into the housing interior, so that there is enough space on the housing to set up the oil discharge cavity. The oil discharge cavity is opened on the housing on the outer periphery of the contact surface between the convex end of the flow splitting piece and the compensation disk. When the first oil port is the oil inlet port, the high-pressure oil enters the distribution disk for distribution work through the compensation oil through hole and the flow splitting oil through hole. When the motor rotates, the high-pressure oil will flow out from the gap between the compensation oil through hole and the flow splitting oil through hole and flow into the oil discharge cavity, and then flow out through the oil discharge port. When the first oil port is the oil return port, at this time, both the compensation oil through hole and the flow splitting oil through hole are low-pressure passages, and the amount of oil flowing out is very small. Therefore, the pressure in the oil discharge cavity is very low, almost zero.

[0017] The oil discharge cavity is connected to the oil discharge port arranged on the valve body through an oil discharge oil path. During use, usually a further oil pipe is connected to the oil discharge port and then to the fuel tank to make the discharged oil flow back to the fuel tank for recycling. However, in actual work, since adding an oil pipe may cause inconvenient pipe layout and other reasons, the oil discharge port can be closed and not used. Therefore, a detachable plug is usually provided on the oil discharge port. In terms of design, the oil discharge oil path is respectively communicated with the first oil port and the second oil port through check valves. When the oil discharge port is normally used, the oil in the oil discharge oil path flows out from the oil discharge port. When the oil discharge port is closed, due to the hydraulic oil in the oil discharge oil path, the check valve communicated with the oil return port is opened, and the oil in the oil discharge oil path flows into the oil return port and flows out together with the oil returning from the oil return port. Since the pressure of the oil return port is not high, an ordinary shaft seal can meet the requirements. Usually, the pressure of the oil return port is very low and can be ignored.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] 1. By setting up the oil discharge cavity, the hydraulic shaft seal does not need to bear high pressure, an ordinary hydraulic shaft seal can be used, the manufacturing cost is reduced, and the service life of the hydraulic shaft seal is extended, and the maintenance cost is reduced.

[0020] 2. By designing the shunt plate and compensation disc, the problem that the existing shaft-rotating cycloid motor cannot add an oil drain function is solved structurally.

[0021] 3. The housing-rotating type can effectively shorten the axial length of the motor, making it convenient to be applied to the walking drive of small machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a sectional structure diagram of the present application.

[0023] Figure 2 It is a sectional structure diagram of the distribution disc.

[0024] Figure 3 It is a front view of the distribution disc.

[0025] Figure 4 It is a sectional structure diagram of the compensation disc.

[0026] Figure 5 It is a front view of the compensation disc.

[0027] Figure 6 It is a sectional structure diagram in the A-A direction.

[0028] Figure 7 It is a sectional structure diagram of the first oil passage.

[0029] Figure 8 It is a sectional structure diagram of the second oil passage.

[0030] In the figure, 1. Front cover, 2. Spline shaft, 3. Inner rotor, 4. Bolt, 5. Outer rotor, 6. Distribution disc, 7. Shunt plate, 8. Hub, 9. Housing, 10. Oil drain port, 11. Spline sleeve, 12. Central oil cavity, 13. Oil drain oil path, 14. Bearing, 15. Oil drain cavity, 16. Compensation oil through hole, 17. Shunt oil through hole, 18. Balance disc, 19. Compensation disc, 19-1. First section, 19-2. Second section, 19-3. Third section, 20. Check valve, 21. Second oil passage, 22. Second oil port, 23. First oil port, 24. First oil passage, 25. Hydraulic shaft seal. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following further describes the present invention in conjunction with the drawings and embodiments.

[0032] As Figure 1 shown, a housing-rotating type cycloid motor with an oil drain function includes a rotating part and a fixed part.

[0033] The rotating part, from left to right, is the front cover 1, balance disk 18, outer rotor 5, valve plate 6, and hub 8. The above components are tightly connected by bolts 4, and sealing rings are provided between each component to seal the connection gaps and prevent oil leakage. Inside the outer rotor 5 is an inner rotor 3, and the center of the inner rotor 3 is connected to a spline shaft 2. The fitting and installation method of the above front cover 1, balance disk 18, outer rotor 5, inner rotor 3, spline shaft 2, and valve plate 6 is the installation method of a prior art cycloid motor.

[0034] The fixed part includes a housing 9. A semi-closed central cavity is opened at the position of the motor axis inside the housing 9. The spline shaft 2 extends into the central cavity from the opening. Along the extending direction of the spline shaft 2, there are a compensation disk 19 and a spline sleeve 11 in sequence. One end of the spline shaft 2 extending into the housing is connected to the spline sleeve 11. Sealing rings are also installed between the outer peripheral sides of the above compensation disk 19 and spline sleeve 11 and the inner wall of the housing.

[0035] The inner peripheral side of the hub 8 is sleeved on the outer peripheral side of the housing. A bearing 14 is installed between the hub 8 and the housing 2, enabling the hub 8 to rotate around the outer peripheral side of the housing 9 with the motor axis as the axis. A part capable of being clamped with the hub 8 is provided on the outer peripheral side of the housing 2, and the part where the hub 8 is clamped with the housing 9 is sealed with a sealing ring.

[0036] As Figure 1 、 Figure 2 、 Figure 3 As shown in

[0037] As Figure 1 、 Figure 4 、 Figure 5As shown in the figure, a compensation disk 17 is provided near the opening of the middle cavity of the housing 9. A through hole is provided in the middle of the compensation disk 17 for the spline shaft to pass through. The compensation disk 17 is in the shape of three hollow cylinders with gradually decreasing diameters. During installation, the section with the smallest diameter is the first section 19-1. The first section 19-1 is fixedly pressed against the inner wall of the housing, and a sealing ring is provided on the outer peripheral side. The second section 19-2 is also fixedly pressed against the inner wall of the housing, and a sealing ring is provided on the outer peripheral side. A gap is left between the surface of the second section 19-2 and the inner wall of the right housing as an oil passage. The left side of the third section 19-3 is in close contact with the protruding part of the shunt plate 7 after the motor is assembled. A number of compensation oil through holes 16 that penetrate the third section 19-3 and the second section 19-2 horizontally are provided on the compensation disk 19. The compensation oil through holes 16 can cooperate with the shunt oil through holes 17 to work.

[0038] After the motor is assembled, the central oil cavity 12 of the motor is jointly formed by the central through hole of the flow distribution disk 6, the central through hole of the compensation disk 19, and the middle cavity of the housing 9. The spline shaft 2 is installed in the central oil cavity 12.

[0039] An oil drain cavity 15 is provided in the housing below the compensation disk 19. The oil drain cavity 15 communicates with the gap where the shunt plate 7 contacts the compensation disk 19, so that the oil leaking from the gap can flow into the oil drain cavity 15. The oil drain cavity 15 is connected to the oil drain port 10 provided on the right side of the housing through the oil drain oil passage 13 at the lower part of the housing. Since all cavities will be filled with hydraulic oil during the operation of the hydraulic system, the position of the oil drain cavity 15 is not necessarily at the lower side, as long as it can communicate with the gap where the shunt plate 7 and the compensation disk 19 contact.

[0040] As Figure 6 shown, the first oil port 23 and the second oil port 22 are also provided on the right side of the housing. The first oil port 23 is connected to the gap between the right side of the second section 19-2 of the compensation disk and the housing 9 through the first oil passage 24. The second oil port 22 is connected to the central oil cavity 12 through the second oil passage 21. The oil drain port 10, the first oil port 23, and the second oil port 22 are all provided on the right side of the housing 9. While the oil drain oil passage 13 is connected to the oil drain port 10, two branch roads are branched out and respectively connected to the first oil port 23 and the second oil port 22, and check valves 20 are installed on both branch roads.

[0041] As Figure 1 、 Figure 7 、 Figure 8As shown, during operation, the first oil port 23 and the second oil port 22 are connected to a hydraulic oil source. When the first oil port 23 is the oil inlet, hydraulic oil enters the gap between the second section 19-2 of the compensation disc and the housing 9 through the first oil passage 24, and enters the distribution hole through the compensation oil passage hole 16 and the branch oil passage hole 17. After distribution, it enters the working oil chamber between the outer rotor 5 and the inner rotor 3, and serves as high-pressure oil to drive the outer rotor 5 to rotate, so that the entire rotating part rotates around the motor axis under the action of the bearing 14; due to the working principle of the cycloid motor, the high-pressure chamber after doing work is replaced by a low-pressure chamber, and the hydraulic oil flows into the central oil chamber 12 after distribution, and flows out from the second oil port 22 through the second oil passage 21. At this time, the second oil port 22 is the oil return port, and the central oil chamber 12 is the low-pressure chamber. And due to the relative rotational movement between the compensation distribution plate 7 and the compensation disc 19, hydraulic oil will leak out from the gap between the end face of the compensation oil passage hole 16 and the end face of the branch oil passage hole 17, and flow into the lower oil drain chamber 15. The hydraulic oil flows out from the oil drain port 10 through the oil drain oil passage 13. Because the above-mentioned gap is extremely small, the amount of leaked hydraulic oil is also very small. Since the hydraulic oil sealed by the hydraulic shaft seal 5 is also this part of the leaked hydraulic oil, the pressure at the hydraulic shaft seal 5 can be reduced, so that the hydraulic oil seal 5 does not need to bear high pressure.

[0042] When the second oil port 22 is the oil inlet, hydraulic oil flows into the central oil chamber 12 through the second oil passage 21, flows into the working oil chamber for work after distribution, and flows out from the first oil port 23 through the first oil passage 24 after passing through the compensation oil passage hole 16 through distribution. At this time, both the compensation oil passage hole 16 and the branch oil passage hole 17 are low-pressure passages, and very little hydraulic oil leaks from the gap. The hydraulic shaft seal 5 also does not need to bear high pressure, and the pressure in the oil drain chamber 15 is also very small at this time.

[0043] Usually, the oil drain port 10 can be connected to a fuel tank to recover the hydraulic oil flowing out of the oil drain port. Sometimes, the oil drain port 10 can also be closed with a plug. At this time, due to the pressure difference between the hydraulic oil in the oil drain oil passage 13 and the hydraulic oil on the oil return port side, the one-way valve 20 on the oil return port side will be opened, so that the oil drain oil passage is connected to the oil return port, and the hydraulic oil in the oil drain chamber can flow back through the oil return port, which can also play a role in reducing the pressure.

[0044] The working principle of the housing-rotating cycloid motor can refer to the prior art. The tire to be driven can be installed on the hub of the rotating part, and the power is directly output by the rotating part, effectively shortening the axial length of the motor. In the housing-rotating cycloid motor, the inner rotor only makes a revolution around the axis inside the outer rotor to achieve the working principle of the cycloid motor for the replacement of the high and low pressure chambers, and does not rotate itself. Therefore, the spline shaft connected only swings and does not rotate, and is not used as a power output part.

Claims

1. A housing-rotating cycloid motor with an oil drainage function, comprising a rotating part and a fixed part. One end of the rotating part is sleeved outside the fixed part and is rotatably connected to the fixed part. The inside of the rotating part is cooperatively connected with the fixed part, and a hydraulic shaft seal is provided at the connection between the fixed part and the rotating part. It further includes a spline shaft. One end of the spline shaft extends into the inside of the rotating part and is connected to the rotating part, and the other end extends into the inside of the fixed part and is connected to the fixed part. Its characteristics are that it further includes an oil drainage cavity. The oil drainage cavity is provided on the outer peripheral side of the connection between the fixed part and the rotating part. The oil drainage cavity is communicated with the connection between the fixed part and the rotating part. The fixed part is also provided with an oil drainage port, and the oil drainage port is communicated with the oil drainage cavity through an oil drainage oil path. The rotating part includes a front cover, an outer rotor, a distribution plate and a hub which are connected in sequence, and also includes an inner rotor. The inner rotor is arranged inside the outer rotor, and the inner rotor cooperates with the outer rotor and the distribution plate to form a working oil cavity. The fixed part includes a housing, and a central oil cavity is arranged inside the housing. The central oil cavity is communicated with the working oil cavity through the distribution plate. The housing is provided with a first oil port and a second oil port. The first oil port is communicated with the working oil cavity through the distribution plate, and the second oil port is communicated with the central oil cavity. It further includes a compensation plate. The compensation plate is arranged inside the central oil cavity, and a number of compensation oil through holes are provided on the compensation plate. One end of the compensation oil through hole is communicated with the first oil port, and the other end is communicated with the working oil cavity through the distribution plate.

2. The cycloid motor with an oil drain function according to claim 1, wherein The front cover, the outer rotor, the distribution plate and the hub can all rotate synchronously around the axis. One end of the spline shaft is cooperatively connected with the inner rotor. It further includes a spline sleeve. The spline sleeve is arranged inside the central oil cavity, and one end of the spline shaft is cooperatively connected with the spline sleeve. The hub is sleeved outside the housing and is rotatably connected to the housing.

3. The cycloid motor with an oil drain function according to claim 2, characterized in that, The spline shaft passes through the compensation plate. One end of the compensation plate is connected to the housing, and the other end is cooperatively connected with the distribution plate.

4. The cycloid motor with an oil drain function according to claim 1, characterized in that The distribution plate is a multi-piece composite distribution plate, and a number of distribution holes are provided on the multi-piece composite distribution plate. The distribution holes are cooperatively communicated with the working oil cavity.

5. The cycloid motor with a shell rotation type according to claim 4, characterized in that, One end of the multi-piece composite distribution plate is further provided with a flow splitting plate. One side of the flow splitting plate is connected to the multi-piece composite distribution plate, and a convex end is provided at the center of the other side. The convex end extends into the housing and is cooperatively connected with the compensation plate. The flow splitting plate is provided with flow splitting oil through holes. One end of the flow splitting oil through hole is communicated with the distribution hole, and the other end is communicated with the compensation oil through hole. The hydraulic shaft seal is sleeved outside the convex end.

6. The cycloid motor with a housing rotation type according to claim 5, characterized in that, The oil drainage cavity is arranged on the housing on the outer peripheral side of the compensation plate. The oil drainage cavity is communicated with the compensation oil through hole and the flow splitting oil through hole through the connection between the compensation plate and the distribution plate.

7. The cycloid motor with an oil draining function according to claim 1, characterized in that, The first oil port and the second oil port are respectively communicated with the oil drainage oil path through one-way valves.

8. The cycloid motor with a shell rotation type according to claim 7, characterized in that, The oil drainage port is provided with a detachable oil drainage port plug.

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