RV speed reducer, robot and detection method for running state of RV speed reducer

Abstract

The invention provides an RV speed reducer, a robot and a detection method for the running state of the RV speed reducer. The RV speed reducer comprises a first shell, a second shell, a crankshaft and a clamp spring, tapered roller bearings are arranged at the two ends of the crankshaft respectively, bearing holes are formed in the first shell and the second shell respectively, the tapered roller bearings are contained in the bearing holes, and the clamp spring is arranged on the outer end faces of the tapered roller bearings to pre-tighten the crankshaft. At least one end of the crankshaft is provided with a pre-tightening force detection element, and the pre-tightening force detection element is located on the side, away from the crankshaft, of the clamping spring, abuts against the clamping spring and is used for detecting the axial pre-tightening force of the crankshaft. The problem that the running state of the RV speed reducer cannot be accurately obtained in real time in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to an RV reducer, a robot, and a method for detecting the operating state of the RV reducer. Background Art

[0002] RV reducer is a new type of cycloid pinwheel planetary transmission mechanism composed of a primary gear transmission and a secondary cycloid transmission. It is mainly used in the joints of industrial robots. It requires high transmission accuracy, small backlash, high rigidity, strong impact resistance, compact structure, and high transmission efficiency for RV reducer. These requirements put forward higher requirements on the structure of RV reducer parts. Therefore, the structure, size, and matching form of bearings of RV reducer parts are key factors that determine the performance of the whole machine and the reliability of the reducer.

[0003] The crankshaft preload of the RV reducer is the key point to determine the transmission accuracy of the RV reducer and the stiffness of the robot system. One of the main features of the RV reducer is the use of an eccentric shaft for transmission. It is used in conjunction with needle bearings and tapered roller bearings to complete its torque transmission and precision maintenance. The use effect and force changes of its tapered roller bearings will reflect the differences in the performance and stiffness of its prototype. When evaluating the load distribution, rigidity and life of the transmission system, the preload of the crankshaft system of the RV reducer and its subsequent changes and fluctuations must be considered at the same time. Although the simulation method can already perform preliminary analysis and calculation on this part, due to the limitations of the simulation model in approaching real things, the reliability, accuracy and feasibility of the simulation results must be verified. It is impossible to intuitively and accurately express the characteristics of the crankshaft preload and crankshaft axial force of the RV reducer, and thus it is impossible to accurately judge the operating status of the RV reducer in real time.

[0004] As can be seen from the above, the existing technology has the problem of being unable to accurately obtain the operating status of the RV reducer in real time. Summary of the invention

[0005] The main purpose of the present invention is to provide an RV reducer, a robot and a method for detecting the operating status of the RV reducer, so as to solve the problem in the prior art that the operating status of the RV reducer cannot be accurately obtained in real time.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an RV reducer, comprising a first housing, a second housing, a crankshaft and a retaining spring, tapered roller bearings are respectively arranged at both ends of the crankshaft, the first housing and the second housing are respectively provided with bearing holes, the tapered roller bearings are accommodated in the bearing holes, the retaining spring is arranged on the outer end surface of the tapered roller bearing to preload the crankshaft, a preload force detection element is arranged at at least one end of the crankshaft, the preload force detection element is located on the side of the retaining spring away from the crankshaft and abuts against the retaining spring, and is used to detect the axial preload force of the crankshaft.

[0007] Furthermore, a preload force detection element is provided at one end of the crankshaft located at the first housing.

[0008] Furthermore, the first shell and / or the second shell is provided with a limit installation groove, the limit installation groove is sequentially connected with the bearing hole, and the retaining spring and the preload force detection element are both accommodated in the limit installation groove.

[0009] Furthermore, the radial length of the limiting installation groove is greater than the diameter of the bearing hole, and the depth of the limiting installation groove is adapted to the thickness of the retaining spring and the preload force detection element.

[0010] Furthermore, the preload force detection element is a piezoelectric sensor.

[0011] Furthermore, the RV reducer also includes a current collection component, which is electrically connected to the piezoelectric sensor and is used to output and display a current value corresponding to the axial preload of the crankshaft.

[0012] Furthermore, the limit installation groove of the RV reducer is a circular groove, the piezoelectric sensor is annular, the piezoelectric sensor includes a signal output end located on the inner ring surface, and the current collection component is electrically connected to the signal output end.

[0013] Further, the first housing is a planet carrier, the second housing is a rigid disk, and the planet carrier has an output end.

[0014] According to another aspect of the present invention, there is provided a robot comprising the above-mentioned RV reducer.

[0015] According to another aspect of the present invention, a method for detecting the operating status of an RV reducer is provided. The above-mentioned RV reducer adopts a detection method, and the detection method includes: obtaining the axial preload of the crankshaft through a preload detection element; obtaining a change curve of the axial preload of the crankshaft in real time during the operation of the RV reducer; determining the change trend of the axial preload of the crankshaft according to the change curve; and determining the operating status of the RV reducer according to the change trend.

[0016] Furthermore, when the changing trend is that the axial preload of the crankshaft is within the preset upper and lower ranges, the RV reducer is in a normal operating state.

[0017] Furthermore, when the changing trend is that the axial preload of the crankshaft gradually decreases, the RV reducer is in a normal wear state.

[0018] Furthermore, when the changing trend is that the axial preload of the crankshaft shows jitter or peak-to-valley values, the RV reducer is in an abnormal operating state.

[0019] According to the technical solution of the present invention, the RV reducer includes a first housing, a second housing, a crankshaft and a retaining spring, tapered roller bearings are respectively arranged at both ends of the crankshaft, bearing holes are respectively opened in the first housing and the second housing, the tapered roller bearings are accommodated in the bearing holes, the retaining spring is arranged on the outer end surface of the tapered roller bearing to preload the crankshaft, and a preload detection element is arranged at at least one end of the crankshaft, the preload detection element is located on the side of the retaining spring away from the crankshaft and abuts against the retaining spring, and is used to detect the axial preload of the crankshaft. In this way, by embedding the preload detection element in the RV reducer, the axial preload of the crankshaft and its changes during the operation of the RV reducer can be accurately obtained in real time, and then the operating state of the RV reducer can be accurately judged in real time according to the changes, which solves the problem that the operating state of the RV reducer cannot be accurately obtained in real time in the prior art. In addition, by adopting the above-mentioned setting, the RV reducer can be adjusted in time while real-time detection, and the operating state of the RV reducer can be judged and adjusted in advance, and faults can be predicted. Furthermore, by monitoring the preload data, the running-in condition of each crankshaft can be recorded, and the operation, wear and impact of the RV reducer can be recorded, so as to more fully accumulate the performance and life data of the RV reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A cross-sectional view of an RV reducer in a specific embodiment of the present invention is shown;

[0022] Figure 2 Shows Figure 1 A partial enlarged view of the middle A;

[0023] Figure 3 A schematic structural diagram of an RV reducer in a specific embodiment of the present invention is shown;

[0024] Figure 4 A schematic structural diagram of a preload force detection element in a specific embodiment of the present invention is shown;

[0025] Figure 5 A flow chart of a method for detecting the operating status of an RV reducer in a specific embodiment of the present invention is shown.

[0026] The above drawings include the following reference numerals:

[0027] 10. First housing; 11. Bearing hole; 12. Limit mounting groove; 13. Avoidance hole; 20. Second housing; 30. Crankshaft; 40. Circlip; 50. Preload force detection element; 51. Signal output terminal; 60. Tapered roller bearing; 70. Planetary gear; 80. Pin gear housing; 90. Angular contact bearing; 100. Cycloidal wheel; 110. Current collection component. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to solve the problem in the prior art that the operating status of an RV reducer cannot be accurately obtained in real time, the present invention provides an RV reducer, a robot and a method for detecting the operating status of an RV reducer.

[0030] like Figure 1 to Figure 2 As shown, the RV reducer includes a first housing 10, a second housing 20, a crankshaft 30 and a retaining spring 40. Tapered roller bearings 60 are respectively provided at both ends of the crankshaft 30, and the first housing 10 and the second housing 20 are respectively provided with bearing holes 11, and the tapered roller bearings 60 are accommodated in the bearing holes 11. The retaining spring 40 is arranged on the outer end surface of the tapered roller bearing 60 to preload the crankshaft 30. A preload force detection element 50 is provided at least at one end of the crankshaft 30. The preload force detection element 50 is located on the side of the retaining spring 40 away from the crankshaft 30 and abuts against the retaining spring 40, and is used to detect the axial preload force of the crankshaft 30. It can be understood that retaining springs 40 are provided at both ends of the crankshaft 30, so that the crankshaft 30 is preloaded from both ends at the same time.

[0031] During the operation of the RV reducer, the crankshaft 30 is the key to driving the transmission of the secondary reducer. The installation and matching requirements of the crankshaft 30 are extremely high, and the corresponding force changes can also directly feedback the operating status of the RV reducer. The crankshaft 30 of the RV reducer provides driving force and a certain rigidity during operation. The two ends of the crankshaft 30 are positioned by tapered roller bearings 60. Therefore, in order to meet the required standards during use, it is necessary to perform a certain pre-tightening installation on it. The pre-tightening amount needs to be strictly controlled, and it will change significantly during operation with the running-in wear and force impact of the prototype. In this embodiment, the two ends of the crankshaft 30 are connected to the tapered roller bearings 60, and the retaining spring 40 is used to install and pre-tighten it. The tapered roller bearings 60 are subjected to forces from both radial and axial directions during the operation of the crankshaft 30. The pre-tightening installation mainly eliminates the clearance of the tapered roller bearings 60 and makes the initial bearing sheet have a certain pre-tightening force. The pre-tightening pressure is mainly reflected in the pressure value in the axial direction.

[0032] The RV reducer includes a first housing 10, a second housing 20, a crankshaft 30 and a retaining spring 40, and tapered roller bearings 60 are respectively arranged at both ends of the crankshaft 30, and the first housing 10 and the second housing 20 are respectively provided with bearing holes 11, and the tapered roller bearings 60 are accommodated in the bearing holes 11, and the retaining spring 40 is arranged on the outer end surface of the tapered roller bearing 60 to preload the crankshaft 30, and at least one end of the crankshaft 30 is provided with a preload detection element 50, and the preload detection element 50 is located on the side of the retaining spring 40 away from the crankshaft 30 and abuts against the retaining spring 40, and is used to detect the axial preload of the crankshaft 30, so that the preload detection element 50 is embedded in the RV reducer, so that the axial preload of the crankshaft 30 and its changes during the operation of the RV reducer can be obtained in real time and accurately, and then the operating state of the RV reducer can be accurately judged in real time according to the changes. In addition, the above-mentioned setting can timely adjust the RV reducer while real-time detection, judge and adjust the operating state of the RV reducer in advance, and predict faults. Furthermore, by monitoring the preload data, the running-in condition of each crankshaft 30 can be recorded, and the operation, wear and impact of the RV reducer can be recorded, so as to more fully accumulate the performance and life data of the RV reducer.

[0033] In this embodiment, if Figure 1 As shown, the first housing 10 is a planet carrier, the second housing 20 is a rigid disk, and the planet carrier has an output end.

[0034] like Figure 1As shown, the RV reducer also includes a planetary gear 70, and the end of the crankshaft 30 close to the second housing 20 is drivingly connected to the planetary gear 70. That is to say, the planetary gear 70 is located on the side of the second housing 20 away from the first housing 10. In this embodiment, a preload detection element 50 is provided at one end of the crankshaft 30 located in the first housing 10. Through the above arrangement, the planetary gear 70 will not interfere with the installation of the preload detection element 50 and the lead-out of the communication line, so it is easy to install. Of course, the preload detection element 50 can also be installed at the end of the crankshaft 30 close to the second housing 20. Furthermore, the preload detection element 50 can be provided at both ends of the crankshaft 30, so as to more accurately detect the axial preload of the crankshaft 30, which can be selected according to actual needs.

[0035] In this embodiment, the first housing 10 is provided with a limited installation groove 12, the limited installation groove 12 is sequentially connected with the bearing hole 11, and the retaining spring 40 and the preload detection element 50 are both accommodated in the limited installation groove 12. Correspondingly, the second housing 20 is provided with a retaining spring limited groove, and the retaining spring 40 is accommodated in the retaining spring limited groove. It can be understood that when the preload detection element 50 can also be installed at one end of the crankshaft 30 close to the second housing 20, the second housing 20 is provided with a limited installation groove 12; when the preload detection element 50 is provided at both ends of the crankshaft 30, the first housing 10 and the second housing 20 are provided with corresponding limited installation grooves 12.

[0036] In this embodiment, the crankshaft 30 is axially preloaded by a retaining spring 40, and the retaining spring 40 bears pressure from the axial direction during the preload process. The present application provides a mounting position for a preload detection element 50 between the retaining spring 40 and the inner end surface of the limit installation groove 12. A preload detection element 50 is installed at one end of each crankshaft 30, which contacts the retaining spring 40 and the inner end surface of the limit installation groove 12. When the crankshaft 30 is preloaded, pressure is generated, and the pressure is transmitted to the preload detection element 50 through the retaining spring 40. When the RV reducer is running, the input shaft rotates to drive the crankshaft 30 to rotate, and the movement of the eccentric block on the crankshaft 30 drives the cycloid wheel 100 to contact the pin teeth, so that the crankshaft 30 rotates and drives the entire secondary transmission to operate.

[0037] In this embodiment, the radial length of the limit installation groove 12 is greater than the diameter of the bearing hole 11, thereby forming a limit step, so that the retaining spring 40 abuts against the limit step for limit. Further, the depth of the limit installation groove 12 is adapted to the thickness of the retaining spring 40 and the preload detection element 50. It can be understood that the above-mentioned depth and thickness are all in the axial direction of the crankshaft 30, so that the retaining spring 40 can abut against the crankshaft 30 and the preload detection element 50 respectively, so as to better transmit the preload.

[0038] In this embodiment, the preload force detection element 50 is a piezoelectric sensor.

[0039] like Figure 1 to Figure 2 As shown, the RV reducer also includes a current acquisition component 110, which is electrically connected to the piezoelectric sensor and is used to output and display the current value corresponding to the axial preload of the crankshaft 30. Specifically, the piezoelectric sensor obtains the change in pressure parameters, and the piezoelectric material generates charges on the surface after the force changes. The charge amplifier measurement circuit amplifies the change in impedance, thereby obtaining a current output proportional to the change in the external force. Furthermore, the current acquisition component 110 also includes a display component, so that the current change value is displayed in real time on the display component, and then the change in preload is intuitively obtained through the change in current, and the operating state of the RV reducer is judged.

[0040] In this embodiment, if Figure 3 to Figure 4 As shown, the position-limiting installation groove 12 is a circular groove, the piezoelectric sensor is annular, the piezoelectric sensor includes a signal output terminal 51 located on the inner annular surface, and the current collection component 110 is electrically connected to the signal output terminal 51. Furthermore, the first housing 10 is also provided with an avoidance hole 13, the diameter of the avoidance hole 13 is smaller than the diameter of the position-limiting installation groove 12, and the communication line of the current collection component 110 passes through the avoidance hole 13 into the RV reducer and is electrically connected to the signal output terminal 51, thereby solving the problem that the existing RV reducer closed structure cannot display the change of the crankshaft preload during operation.

[0041] like Figure 1 As shown, the RV reducer further includes a pin gear housing 80 and an angular contact bearing 90. The angular contact bearing 90 is located between the pin gear housing 80 and the first housing 10 and the second housing 20, so that the first housing 10 and the second housing 20 can support the crankshaft 30 in a rotatable manner.

[0042] The present application also provides a robot comprising the above-mentioned RV reducer.

[0043] like Figure 5 As shown, the present application also provides a method for detecting the operating status of an RV reducer. The above-mentioned RV reducer adopts the detection method, and the detection method includes: obtaining the axial preload force of the crankshaft 30 through the preload force detection element 50; obtaining the change curve of the axial preload force of the crankshaft 30 in real time during the operation of the RV reducer; determining the change trend of the axial preload force of the crankshaft 30 according to the change curve; and determining the operating status of the RV reducer according to the change trend.

[0044] Specifically, the variation curve in this embodiment is automatically generated by a control module or computer software according to the acquired value of the axial preload force of the crankshaft 30 .

[0045] In this embodiment, when the change trend is that the axial preload of the crankshaft 30 is within the preset upper and lower ranges, the RV reducer is in a normal operating state. Specifically, when the current indication fluctuates slightly and is in a stable range, it means that the axial preload of the crankshaft 30 is stable and operating normally, and the RV reducer is in a good state.

[0046] In this embodiment, when the change trend is that the axial preload of the crankshaft 30 gradually decreases, the RV reducer is in a normal wear state. Specifically, as the running time of the RV reducer increases, when the current indication begins to change slowly and steadily in a single direction, it indicates that the crankshaft 30 is worn and the preload becomes smaller, but because the change is slow and relatively stable, it can be considered that the RV reducer is in a normal wear state and needs attention.

[0047] In this embodiment, when the change trend is that the axial preload force of the crankshaft 30 shows jitter or peak-to-valley values, the RV reducer is in an abnormal operating state. Specifically, when the current reading shows violent jitter or obvious peak-to-valley values, it indicates that the operation of the crankshaft 30 is abnormal, resulting in stress concentration or impact on the crankshaft 30 in the axial direction, and the internal operation state of the RV reducer is abnormal, and axial force or impact occurs, such as abnormal wear of the internal parts of the RV reducer, bearing damage, and parts peeling, etc., indicating that the RV reducer has already experienced pre-failure phenomena, and it is necessary to optimize it in a targeted manner, replace or optimize parts and working conditions, and avoid serious damage and failure of the prototype, so as to more accurately judge in real time that the transmission performance of the RV reducer has deteriorated and reduce losses.

[0048] From the above description, it can be seen that the above-mentioned embodiment of the present invention achieves the following technical effects: by setting the RV reducer including the first housing 10, the second housing 20, the crankshaft 30 and the retaining spring 40, tapered roller bearings 60 are respectively provided at both ends of the crankshaft 30, the first housing 10 and the second housing 20 are respectively provided with bearing holes 11, the tapered roller bearings 60 are accommodated in the bearing holes 11, the retaining spring 40 is arranged on the outer end surface of the tapered roller bearing 60 to preload the crankshaft 30, and at least one end of the crankshaft 30 is provided with a preload detection element 50, the preload detection element 50 is located on the side of the retaining spring 40 away from the crankshaft 30 and abuts against the retaining spring 40, and is used to detect the axial preload of the crankshaft 30, so that by embedding the preload detection element 50 in the RV reducer, the axial preload of the crankshaft 30 and its changes during the operation of the RV reducer can be obtained in real time and accurately, and then the operating state of the RV reducer can be accurately judged in real time according to the changes. In addition, by adopting the above-mentioned setting, the RV reducer can be adjusted in time during real-time detection, and the operating state of the RV reducer can be judged and adjusted in advance, and faults can be predicted. Furthermore, by monitoring the preload data, the running-in condition of each crankshaft 30 can be recorded, and the operation, wear and impact of the RV reducer can be recorded, so as to more fully accumulate the performance and life data of the RV reducer.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0051] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0052] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.

[0053] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0054] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0055] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An RV reducer, characterized in that: The invention comprises a first housing (10), a second housing (20), a crankshaft (30) and a retaining spring (40), wherein tapered roller bearings (60) are respectively arranged at both ends of the crankshaft (30), the first housing (10) and the second housing (20) are respectively provided with bearing holes (11), the tapered roller bearings (60) are accommodated in the bearing holes (11), the retaining spring (40) is arranged on the outer end surface of the tapered roller bearing (60) to preload the crankshaft (30), and a preload force detection element (50) is arranged at at least one end of the crankshaft (30), the preload force detection element (50) is located on a side of the retaining spring (40) away from the crankshaft (30) and abuts against the retaining spring (40) for detecting the axial preload force of the crankshaft (30).

2. The RV reducer according to claim 1, characterized in that: The preload force detection element (50) is provided at one end of the crankshaft (30) located on the first housing (10).

3. The RV reducer according to claim 1, characterized in that: The first housing (10) and / or the second housing (20) is provided with a limit installation groove (12), the limit installation groove (12) is sequentially connected with the bearing hole (11), and the retaining spring (40) and the preload detection element (50) are both accommodated in the limit installation groove (12).

4. The RV reducer according to claim 3, characterized in that: The radial length of the limiting installation groove (12) is greater than the diameter of the bearing hole (11), and the depth of the limiting installation groove (12) is compatible with the thickness of the retaining spring (40) and the preload detection element (50).

5. The RV reducer according to claim 1, characterized in that: The preload force detection element (50) is a piezoelectric sensor.

6. The RV reducer according to claim 5, characterized in that: The RV reducer further comprises a current collection component (110), wherein the current collection component (110) is electrically connected to the piezoelectric sensor and is used to output and display a current value corresponding to the axial preload force of the crankshaft (30).

7. The RV reducer according to claim 6, characterized in that: The limit installation groove (12) of the RV reducer is a circular groove, the piezoelectric sensor is annular, the piezoelectric sensor includes a signal output end (51) located on the inner ring surface, and the current collection component (110) is electrically connected to the signal output end (51).

8. The RV reducer according to any one of claims 1 to 7, characterized in that: The first housing (10) is a planet carrier, the second housing (20) is a rigid disk, and the planet carrier has an output end.

9. A robot, characterized in that: An RV reducer comprising the RV reducer according to any one of claims 1 to 8.

10. A method for detecting the operating status of an RV reducer, characterized in that: The RV reducer according to any one of claims 1 to 8 adopts the detection method, and the detection method comprises: Acquiring the axial preload force of the crankshaft (30) through the preload force detection element (50); acquiring in real time a curve of a change in the axial preload force of the crankshaft (30) during operation of the RV reducer; Determining a change trend of the axial preload force of the crankshaft (30) according to the change curve; The operating state of the RV reducer is determined according to the change trend.

11. The method for detecting the operating state of an RV reducer according to claim 10, characterized in that: When the variation trend is that the axial preload force of the crankshaft (30) is within a preset upper and lower range, the RV reducer is in a normal operating state.

12. The method for detecting the operating state of an RV reducer according to claim 10, characterized in that: When the variation trend is that the axial preload force of the crankshaft (30) gradually decreases, the RV reducer is in a normal wear state.

13. The method for detecting the operating state of an RV reducer according to claim 10, characterized in that: When the variation trend is that the axial preload force of the crankshaft (30) vibrates or has peak-to-valley values, the RV reducer is in an abnormal operating state.

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