Device for determining oil leakage and robot using the same

Abstract

A device for determining oil leakage of a gearbox and an associated robot. The device includes an expandable ring arranged around an output shaft of a motor coupled to the gearbox, the expandable ring expanding when in contact with oil to apply a radial force to the output shaft; and a controller configured to detect oil leakage by detecting at least one of the following items caused by the applied radial force: a change in torque on the output shaft, or a change in current used to drive the motor, with the device, before oil leaks into the motor, the user already knows or the motor has stopped. In this case, the robot using the device can be operated more safely.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to a robot, and more particularly to an apparatus for determining oil leakage of a gear box used in a joint of the robot. Background Art

[0002] Robots are widely used automated mechanisms that increase operational efficiency and accuracy. Robots generally include robot arm links and joints. The robot arm links can be driven to rotate or move by a motor set in the joint or base. In order to meet the reduction ratio requirements, a gearbox needs to be arranged between the motor and the robot arm link to be driven. A gearbox is a device that uses gears and gear trains to provide speed and torque conversion from a rotating power source to another device.

[0003] Oil is usually provided in the gearbox to provide lubrication for the gears and other components. In addition to the lubrication function for the individual elements to significantly reduce friction, the oil in the gearbox can also cool heated sub-assemblies and ease and weaken the gear stroke. In addition, it reduces vibrations, prevents corrosion, and keeps everything clean.

[0004] For robotic applications, the motor is usually coupled to a gearbox, wherein the shaft of the motor extends into the oil cavity of the gearbox. Aging of the seal used to seal the oil cavity leads to problems in preventing the oil in the oil cavity from entering the motor, thereby adversely affecting the operation of the motor. Summary of the invention

[0005] Embodiments of the present disclosure provide an apparatus and an associated robot for determining oil leakage of a gearbox to at least partially address the above-mentioned and other potential problems.

[0006] In a first aspect, an apparatus for determining oil leakage of a gearbox is provided. The apparatus comprises an expandable ring disposed around an output shaft of a motor coupled to the gearbox, the expandable ring expanding upon contact with oil to apply a radial force to the output shaft; and a controller configured to detect the oil leakage by detecting at least one of the following items caused by the applied radial force: a change in torque on the output shaft, or a change in current used to drive the motor.

[0007] With the device according to an embodiment of the present disclosure, the user already knows that the leak or the motor has stopped before the oil leaks into the motor. In this case, the user may only need to replace the damaged or aged sealing ring to restore the robot joint to a normal operating state. In this way, maintenance costs can be reduced. More importantly, a robot using the device according to an embodiment of the present disclosure can be operated more safely.

[0008] In some embodiments, the device further comprises a housing, which is arranged on the fixed part of the motor and comprises a receiving portion for receiving the expandable ring. In this way, the device can be more easily mounted on the motor.

[0009] In some embodiments, the expandable ring is arranged to contact the side of the receiving portion away from the output shaft. This arrangement can easily achieve the radial force applied to the output shaft.

[0010] In some embodiments, the expandable ring includes an expansion portion made of a functional oil absorbing material so that the expansion portion expands when the expansion portion contacts oil. The oil-swelling rubber can ensure that the device expands and applies radial force to the output shaft, thereby improving the reliability of the device.

[0011] In some embodiments, the expandable ring further comprises a contact portion, which is arranged on one side of the expansion portion adjacent to the output shaft in the radial direction, and wherein the contact portion is made of nitrile rubber. The contact portion can ensure sufficient radial force applied to the output shaft, so that a torque change on the output shaft or a current change for driving the motor can be detected. In this way, the reliability of the device is further improved.

[0012] In some embodiments, the functional oil absorbing material comprises oil swellable rubber.

[0013] In some embodiments, the device further comprises an additional sleeve, which is arranged on the output shaft and is adapted to rotate together with the output shaft. This arrangement can improve the adaptability of the device.

[0014] In some embodiments, an expandable ring is arranged between the additional sleeve and the housing.

[0015] In some embodiments, the device further comprises a radial seal disposed between the additional sleeve and the housing.

[0016] In some embodiments, the controller is coupled to a power cable or driver for the motor to detect changes in the current used to drive the motor.

[0017] In a second aspect, a robot is provided, comprising at least one joint and at least one device according to the first aspect.

[0018] It should be understood that the invention summary is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally denote like components throughout the exemplary embodiments of the present disclosure.

[0020] Figure 1 shows a simplified cross-sectional view of an apparatus for determining oil leakage of a gearbox arranged between the gearbox and a motor according to an embodiment of the present disclosure;

[0021] Figure 2 A simplified cross-sectional view showing an apparatus for determining oil leakage of a gearbox arranged between the gearbox and a motor according to other embodiments of the present disclosure; and

[0022] Figure 3 A perspective view of an apparatus according to a further embodiment of the present disclosure is shown.

[0023] Throughout the drawings, the same or similar reference numbers are used to refer to the same or similar elements. DETAILED DESCRIPTION

[0024] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thereby implement the present disclosure, rather than implying any limitation on the scope of the subject matter.

[0025] As used herein, the term "including" and its variations should be interpreted as open-ended terms, which mean "including but not limited to". The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may be included below. Unless the context clearly indicates otherwise, the definitions of terms are consistent throughout the specification.

[0026] Gearboxes and motors are common components in robot joints. The motor 202 usually includes a brake mechanism to quickly reduce the rotation speed of the arm of the joint or to hold the arm of the joint in place. The gearbox 201 is usually provided with an oil chamber for receiving oil to lubricate the various components, thereby substantially reducing friction and achieving other necessary functions. In order to make the joint more compact, the shaft of the motor is usually inserted into the oil chamber to mesh with the gear arranged in the oil chamber.

[0027] A seal is provided around the shaft of the motor 202 to prevent oil from entering the motor 202. However, in the case of long-term operation, the seal around the shaft of the motor 202 may fail due to long-term wear, which will cause oil to enter the motor 202. The oil entering the motor 202 will accelerate the aging of the insulating components in the motor 202. In addition, more importantly, once the oil enters the brake mechanism of the motor, there is a risk of failure of the brake mechanism, which may cause a major accident. For example, if the brake mechanism of the motor for stopping or holding the second arm and the third arm fails, the third arm may slide down due to the failure of the brake mechanism, which may damage surrounding devices and / or threaten personal safety.

[0028] A conventional solution to prevent oil from entering the motor 202 is to use a double seal structure including two seals. A detection hole is provided between the two seals for the operator to observe oil leaking through one of the seals adjacent to the oil chamber in the seal. If oil is observed through the detection hole, it means that at least one of the two seals is damaged and the motor 202 or the double seal structure needs to be replaced in time. However, there is currently no way to know whether the motor 202 enclosed in the joint has oil leakage.

[0029] To at least partially address the above and other potential problems, an embodiment of the present disclosure provides an apparatus 100 for determining oil leakage of a gearbox 201 . Figure 1 and Figure 2 A simplified cross-sectional view of an apparatus 100 for determining oil leakage of a gearbox 201 arranged between the gearbox 201 and a motor 202 according to an embodiment of the present disclosure is shown.

[0030] like Figure 1 and Figure 2 As shown, generally, the device 100 includes an expandable ring 101 and a controller 102. The expandable ring 101 is arranged around an output shaft 2021 of a motor 202 coupled to a gearbox 201. That is, the expandable ring 101 is arranged outside the gearbox 201 but around the output shaft 2021. When oil does not leak from the gearbox 201, the expandable ring 101 will not contact the output shaft. When contacting the oil, the expandable ring 101 can expand to contact the output shaft and apply a radial force to the output shaft 2021.

[0031] As can be seen from the above, when there is no oil leakage from the gear box 201, the expandable ring 101 does not contact the output shaft, and the motor 202 can drive the gear box 201 to work normally through the output shaft 2021. When oil leakage of the gear box 201 occurs, the expandable ring 101 is arranged so that the oil leaked from the gear box 201 will first contact the expandable ring 101. As a result, the expandable ring 101 expands to apply a radial force to the output shaft 2021.

[0032] Therefore, the torque on the output shaft 2021 will change in response to the radial force applied by the expandable ring 101. The current used to drive the motor 202 will increase accordingly compared to the case where no radial force is applied. The controller 102 can detect the change in torque on the output shaft 2021 and / or the change in current used to drive the motor 202. In response to the detection of the change in torque on the output shaft 2021 and / or the change in current used to drive the motor 202, the controller 102 can determine or detect oil leakage of the gearbox 201.

[0033] In some embodiments, in order to improve the reliability of the device 100, a reference value of the torque on the output shaft 2021 and / or the current used to drive the motor 202 may be provided. For example, under normal conditions, i.e., without oil leakage, when the robot performs certain predetermined operations, the torque of the output shaft 2021 of the motor 202 or the current value used to drive the motor 202 may be recorded as a reference value. The predetermined operations may be some operations routinely performed by the robot.

[0034] The controller 102 will detect the torque and / or current during each subsequent predetermined operation. If the difference between the torque and / or current and the reference value exceeds the corresponding threshold value, the controller 102 can determine that the expandable ring 101 has applied a radial force on the output shaft 2021. The radial force applied by the expandable ring 101 means that the expandable ring 101 is in contact with the oil leaking from the gearbox 201. Therefore, the controller 102 can then determine or detect oil leakage by detecting a change in torque on the output shaft 2021 and / or a change in current used to drive the motor 202.

[0035] The controller 102 may also determine that the increase in torque or current is not caused by other factors. For example, in some embodiments, the controller 102 may also employ other sensors coupled to the robot, such as load sensors, to determine that the increase in torque or current is caused by the radial force applied by the expandable ring, rather than other factors such as an increase in the load applied to the robot.

[0036] In some embodiments, the device 100 may also notify the user about the determined oil leak. For example, when the controller 102 determines that an oil leak has occurred in the gearbox 201, the controller 102 may directly or indirectly push a notification or warning of the oil leak to an external device, such as a cellular phone used by the user, through other controllers 102. Alternatively or additionally, the controller 102 may also be configured to stop the motor 202 when an oil leak is determined before notifying or warning the user. In some embodiments, the controller 102 may be a controller 102 of a robot using the device 100. In some alternative embodiments, the controller 102 may also be a controller 102 independent of the controller 102 of the robot.

[0037] In this way, before the oil leaks to the motor 202, the user already knows that the motor 202 has stopped. In this case, the user may only need to replace the damaged sealing ring to restore the robot joint to a normal operating state. In this way, maintenance costs can be reduced. More importantly, a robot using the device 100 according to an embodiment of the present disclosure can be operated more safely.

[0038] In some embodiments, the motor 202 can detect a change in the current used to drive the motor 202 through a power cable coupled to the motor 202. As described above, the current used to drive the motor 202 changes according to the torque of the output shaft 2021 of the motor. In some embodiments, the controller 102 can be coupled to the driver of the motor 202 to detect the change in current. In this way, the controller 102 can more easily detect or determine oil leakage of the gear box 201.

[0039] In some embodiments, the device 100 may further include a housing 103 disposed on the fixed portion 2022 of the motor 202. Figure 1 and Figure 2 As shown. The fixing portion 2022 of the motor 202 refers to the external fixing portion of the motor 202. For example, the fixing portion 2022 of the motor 202 may be the outer shell of the motor 202. The housing 103 may be arranged on the outer shell of the motor 202 in any suitable manner, such as by interference fit, fastener connection, etc. The housing 103 includes a receiving portion 1031 for receiving a base. As a result, the device 100 can be easily installed between the motor 202 and the gear box 201.

[0040] In order to ensure that the expandable ring 101 can apply sufficient radial force to the output shaft 2021, in some embodiments, the expandable ring 101 is arranged to contact the side of the receiving portion 1031 away from the output shaft 2021, such as Figure 1 and Figure 2 In this way, the expandable ring 101 can expand more toward the output shaft 2021 to apply sufficient radial force on the output shaft 2021 .

[0041] In some embodiments, the expandable ring 101 may include an expansion portion 1011 made of a functional oil-absorbing material, which can expand when it contacts oil. For example, in some embodiments, the functional oil-absorbing material includes oil-swelling rubber. That is, the expansion portion 1011 can be made of oil-swelling rubber. Oil-swelling rubber is a type of polymer-functional oil-absorbing material, which mainly includes a rubber matrix and a lipophilic functional group or a lipophilic component. The expansion portion 1011 made of oil-swelling rubber can expand when it contacts oil. In addition, the expansion portion 1011 can be used as an additional seal to prevent oil from entering the motor 202.

[0042] Of course, it should be understood that the embodiment in which the functional oil absorbing material comprises oil swelling rubber is for illustrative purposes only and does not imply any limitation on the scope of the present disclosure. Any other suitable material that can swell when exposed to or in contact with oil is also possible. For example, in some alternative embodiments, the functional oil absorbing material may also include a polymer material, such as a resin that swells when exposed to oil.

[0043] In some embodiments, the entire body of the expandable ring 101 may be composed of oil-swellable rubber. To ensure that sufficient radial force is applied to the output shaft 2021, in some embodiments, the oil-swellable rubber may be modified to be able to apply sufficient radial force during the expansion process.

[0044] In some embodiments, Figure 3 As shown, in addition to the expansion portion 1011, the expandable ring 101 may also include a contact portion 1012. The contact portion 1012 is arranged on a side of the expansion portion 1011 adjacent to the output shaft 2021 in the radial direction. The contact portion 1012 may be made of nitrile rubber, which has a higher hardness and lower deformability than oil-expandable rubber. Through the contact portion 1012, the expandable ring 101 may apply sufficient radial force on the output shaft 2021.

[0045] Of course, it should be understood that the embodiment in which the contact portion 1012 is made of nitrile rubber is for illustrative purposes only and does not imply any limitation on the scope of the present disclosure. Other materials or structures with higher hardness and / or lower deformability than oil-swellable rubber are also possible. For example, the contact portion 1012 may also be made of metal or plastic materials, etc. In some embodiments, the contact portion 1012 may include a plurality of segments uniformly arranged on the radial inner side of the expansion portion 1011.

[0046] In some embodiments, the device 100 may further include a radial seal 105 between the output shaft 2021 of the motor 202 and the housing 103, such as Figure 1 and Figure 2 As shown. The radial seal 105 can provide additional sealing protection for the oil chamber of the gear box 201. Due to the radial seal 105, the oil leaking from the gear box 201 will first be prevented from leaking to the outside of the device 100 without affecting the motor 202. Even if the radial seal 105 is damaged, the oil leakage can be known in time before it enters the motor 202. Only the seal of the gear box 201 and the radial seal 105 of the device 100 need to be replaced, without replacing the motor 202 or the entire joint, which significantly reduces the cost.

[0047] In some embodiments, in order to improve adaptability, the device 100 may further include an additional sleeve 104, such as Figure 1As shown. The additional sleeve 104 can be arranged on the output shaft 2021 of the motor 202 and can rotate together with the output shaft 2021. In those embodiments, the radial seal 105 and the expandable ring 101 are arranged between the additional sleeve 104 and the housing 103. In this way, no matter how the output shaft 2021 of the motor 202 is structured, the device 100 can be applied thereto. As a result, the device 100 can be applied to various motors, which significantly improves the adaptability of the device 100.

[0048] According to other aspects of the present disclosure, a robot is provided. The robot includes at least one joint and at least one device 100 as described above. By using the device 100 according to an embodiment of the present disclosure, oil leakage of the gearbox 201 can be determined in time before affecting the performance of the motor 202. In this way, the reliability of the robot is improved.

[0049] It should be understood that the above detailed embodiments of the present disclosure are only used to illustrate or explain the principles of the present disclosure, rather than to limit the present disclosure. Therefore, without departing from the spirit and scope of the present disclosure, any modification, equivalent replacement and improvement, etc. should be included in the protection scope of the present disclosure. At the same time, the attached claims of the present disclosure are intended to cover all changes and modifications that fall within the scope and limits of the claims or the equivalents of the scope and limits.

Claims

1. A device for determining oil leakage of a gearbox (201), comprising: an expandable ring (101) arranged around an output shaft (2021) of a motor (202) coupled to the gearbox (201), the expandable ring (101) expanding when contacting oil to apply a radial force to the output shaft (2021); and A controller (102) is configured to detect the oil leakage by detecting at least one of the following items caused by the applied radial force: a change in torque on the output shaft (2021), or a change in current used to drive the motor (202).

2. The apparatus according to claim 1, further comprising: A housing (103) is arranged on the fixing portion (2022) of the motor (202) and includes a receiving portion (1031) for receiving the expandable ring (101).

3. The device according to claim 2, wherein the expandable ring (101) is arranged to be in contact with a side of the receiving portion (1031) away from the output shaft (2021).

4. The device according to claim 1, wherein the expandable ring (101) includes an expansion portion (1011) made of a functional oil-absorbing material, so that the expansion portion (1011) expands when the expansion portion (1011) contacts oil.

5. The device according to claim 4, wherein the expandable ring (101) further includes a contact portion (1012), wherein the contact portion (1012) is arranged on a side of the expansion portion (1011) adjacent to the output shaft (2021) in a radial direction, and wherein the contact portion (1012) is made of nitrile rubber.

6. The device of claim 4, wherein the functional oil absorbing material comprises oil-swelling rubber.

7. The device according to any one of claims 2-3, wherein the expandable ring (101) comprises an expansion portion (1011) made of a functional oil-absorbing material, so that the expansion portion (1011) expands when the expansion portion (1011) contacts oil.

8. A device according to claim 7, wherein the expandable ring (101) further includes a contact portion (1012), wherein the contact portion (1012) is arranged on a side of the expansion portion (1011) adjacent to the output shaft (2021) in a radial direction, and wherein the contact portion (1012) is made of nitrile rubber.

9. The device of claim 7, wherein the functional oil absorbing material comprises oil-swellable rubber.

10. The device according to any one of claims 2, 3, 8 and 9, further comprising: An additional sleeve (104) is arranged on the output shaft (2021) and is suitable for rotating together with the output shaft (2021).

11. Device according to claim 10, wherein the expandable ring (101) is arranged between the additional sleeve (104) and the housing (103).

12. The apparatus according to claim 10, further comprising: A radial seal (105) is arranged between the additional sleeve (104) and the housing (103).

13. The apparatus of claim 1, wherein the controller (102) is coupled to a power cable or a driver of the motor (202) to detect changes in current used to drive the motor (202).

14. A robot comprising: at least one joint; as well as At least one device according to any one of claims 1 to 13 is arranged on the at least one joint.

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