Electric push rod for finger joint active and passive training system

Abstract

The utility model belongs to the technical field of electric push rods, and provides an electric push rod for a finger joint active and passive training system, which comprises a power mechanism and a telescopic mechanism, the power structure comprises a shell, a brushless motor and a planetary reducer, the brushless motor and the planetary reducer are arranged in the shell, the brushless motor is arranged at one end of the shell, an output shaft of the brushless motor is in transmission connection with the planetary reducer, a tail shaft of the brushless motor is provided with an encoder, and the end, away from the brushless motor, of the planetary reducer is provided with a zero position detection sensor. The telescopic mechanism comprises a guide pipe, a lead screw, a lead screw nut and a push rod piece, the guide pipe is connected to the end, close to the planetary reducer, of the shell, one end of the lead screw is connected with the output end of the planetary reducer, the other end of the lead screw extends into the guide pipe to be in threaded fit with the lead screw nut, and the push rod piece is arranged in the guide pipe. The lead screw nut is fixedly connected with the push rod piece; the electric push rod has the advantages of being simple and compact in structure, high in control precision and good in stability.

Description

Technical Field

[0001] This utility model relates to the field of electric linear actuator technology, and in particular to an electric linear actuator for a finger joint active and passive training system. Background Technology

[0002] There are many stroke patients in China, and stroke patients will be left with sequelae of varying degrees after the onset of the disease. Among the many sequelae, hemiplegia has the highest incidence. Among the rehabilitation of hemiplegia, the rehabilitation of hand function is the most difficult. Usually, in order to accelerate the recovery of some or all finger functions, the active and passive training system of finger joints is used to carry out rehabilitation training for the patient's fingers.

[0003] The electric linear actuators used in finger joint active and passive training systems generally require small size and high precision due to the specific applications. However, existing electric linear actuators typically use brushed motors and ordinary gear reducers as the power source to drive the actuator. These types of electric linear actuators have large backlash, low control precision, and cannot be precisely controlled. Moreover, their overall size is relatively large, making it difficult to meet the needs of finger joint active and passive training systems.

[0004] The technical problem to be solved by this utility model is: how to solve the problem that existing electric linear actuators have defects such as low precision, large size and low stability, and are not suitable for active and passive training systems for finger joints. Utility Model Content

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide an electric push rod for a finger joint active and passive training system, which has the characteristics of simple and compact structure, high control precision and good stability.

[0006] The technical solution adopted by this utility model is: an electric push rod for a finger joint active and passive training system, including a power mechanism and a telescopic mechanism;

[0007] The power mechanism includes a housing, a brushless motor and a planetary reducer respectively built into the housing. The brushless motor is located at one end of the housing. The output shaft of the brushless motor is connected to the planetary reducer. An encoder is installed on the tail shaft of the brushless motor. A zero-position detection sensor is installed at the end of the planetary reducer away from the brushless motor.

[0008] The telescopic mechanism includes a guide tube, a lead screw, a lead screw nut, and a push rod. The guide tube is connected to one end of the housing near the planetary reducer. One end of the lead screw is connected to the output end of the planetary reducer, and the other end extends into the guide tube and is threadedly engaged with the lead screw nut. The push rod is built into the guide tube. The lead screw nut is slidably connected to the guide tube, and the lead screw nut is fixedly connected to the push rod.

[0009] The electric linear actuator used in the active and passive finger joint training system of this application, by employing a brushless motor and a planetary reducer as the power source, can greatly improve the service life of the electric linear actuator, make it quieter during use, and improve the user experience. Moreover, the planetary reducer has a more compact structure and can achieve a higher rated output torque, thereby reducing the overall size of the electric linear actuator. At the same time, the planetary reducer makes the return backlash of the electric linear actuator smaller and improves the running accuracy. The encoder can detect the rotation speed and angle of the brushless motor tail shaft, and through calculation, the extension length of the linear actuator can be known in real time. This allows for precise control of the extension length of the linear actuator. In conjunction with the zero-position detection sensor to check whether the lead screw nut has returned to the zero position, it can be reset to zero position to avoid cumulative errors after long-term use, further improving the running accuracy of the electric linear actuator and enhancing the competitiveness of the product.

[0010] In some embodiments, the push rod is sleeved on the outer surface of the lead screw, and the lead screw nut is located at the end of the push rod near the planetary reducer.

[0011] By adopting the above technical solution, the push rod is sleeved on the outer surface of the lead screw, which can make full use of space and make the overall structure of the electric push rod more compact.

[0012] In some embodiments, a guide block is provided on the outer side of the lead screw nut, and a groove is provided on the inner wall of the guide tube to slide in cooperation with the guide block.

[0013] By adopting the above technical solution, the running trajectory of the lead screw nut can be restricted by the cooperation of the guide block and the slide groove, thereby improving the accuracy of the extension and retraction of the push rod.

[0014] In some implementations, the lead screw nut is made of PEEK material.

[0015] Using the above technical solution, PEEK (polyether ether ketone) is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing and high mechanical strength. Screw nuts made of PEEK material are quieter and more durable, which helps to extend the service life of electric actuators.

[0016] In some embodiments, the telescopic mechanism also includes a bearing built into the housing, the bearing being located at the end of the planetary reducer near the lead screw, with the head of the lead screw passing through the inner hole of the bearing.

[0017] By adopting the above technical solution, the bearing can support the lead screw, prevent the lead screw from deforming, and improve the fitting accuracy between the lead screw and the lead screw nut.

[0018] In some embodiments, the end of the guide tube away from the outer casing is connected to a guide seat, and the guide seat is provided with a guide hole that slides with the push rod.

[0019] By adopting the above technical solution, the guide seat can provide support for the push rod, so that the push rod can remain straight, while the guide hole can restrict the running trajectory of the push rod and improve the accuracy of the push rod's extension and retraction.

[0020] In some implementations, an external connector is provided at the end of the push rod that is away from the planetary reducer, and the external connector is detachably connected to the push rod by fasteners.

[0021] By adopting the above technical solution, the external connector facilitates the connection between the push rod and the external finger joint clamp. The detachable connection method allows for the replacement of different external connectors as needed, resulting in better versatility.

[0022] In some implementations, the fastener is a reamed hole screw.

[0023] By adopting the above technical solution, the external connector is connected by a reamed hole screw, making the rotation angle between the push rod and the external connector controllable. No additional rotary joint is required for installation, making installation and use more convenient.

[0024] In some embodiments, the output end of the planetary reducer is provided with a drive shaft, the end of the drive shaft near the lead screw is provided with a protrusion, and the end of the lead screw near the planetary reducer is provided with a groove that engages with the protrusion.

[0025] By adopting the above technical solution, the connection between the lead screw and the drive shaft can be made more convenient through the cooperation of the protrusion and the groove. On the other hand, this cooperation structure has a strong load-bearing capacity and can carry out high-speed and high-torque transmission.

[0026] In some embodiments, the planetary reducer includes a base, a cylinder, and multiple sets of planetary gears. The cylinder is located at one end of the base near the brushless motor. Each set of planetary gears is built into the cylinder along the axial direction of the cylinder. A gear ring is provided on the inner wall of the cylinder. The end of the drive shaft away from the protrusion passes through the base and is fixedly connected to the planet carrier in the last set of planetary gears.

[0027] The above technical solution makes the planetary reducer more compact and helps to reduce the overall size of the electric actuator. Attached Figure Description

[0028] Figure 1 This is a cross-sectional schematic diagram of the electric push rod used in the active and passive finger joint training system according to the first embodiment of this utility model;

[0029] Figure 2 for Figure 1 The diagram shows the structure of the planetary reducer in the electric push rod used in the active and passive finger joint training system.

[0030] In the diagram: 100, Electric push rod for the active and passive finger joint training system; 10, Power mechanism; 11, Housing; 12, Brushless motor; 13, Planetary reducer; 131, Drive shaft; 132, Protrusion; 133, Base; 134, Cylinder; 135, Planetary gear set; 14, Encoder; 15, Zero-position detection sensor; 20, Telescopic mechanism; 21, Guide tube; 22, Lead screw; 23, Lead screw nut; 24, Push rod component; 25, Bearing; 26, Guide seat; 27, External connector. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. When the number of elements is referred to as "multiple," it can be any number of two or more. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Please see Figure 1 and Figure 2An electric push rod 100 for a finger joint active and passive training system, according to a preferred embodiment of the present invention, includes a power mechanism 10 and a telescopic mechanism 20. The power mechanism 10 includes a housing 11, a brushless motor 12 and a planetary reducer 13 respectively built into the housing 11. The brushless motor 12 is located at one end of the housing 11, and the output shaft of the brushless motor 12 is connected to the planetary reducer 13 for transmission. An encoder 14 is provided on the tail shaft of the brushless motor 12, and a zero-position detection sensor 15 is provided at the end of the planetary reducer 13 away from the brushless motor 12. The telescopic mechanism 20 includes a guide tube 21, a lead screw 22, a lead screw nut 23 and a push rod 24. The guide tube 21 is connected to the end of the housing 11 near the planetary reducer 13. One end of the lead screw 22 is connected to the output end of the planetary reducer 13, and the other end extends into the guide tube 21 and is threadedly engaged with the lead screw nut 23. The push rod 24 is built into the guide tube 21, and the lead screw nut 23 is slidably connected to the guide tube 21 and fixedly connected to the push rod 24.

[0035] The electric actuator 100 used in the active and passive finger joint training system of this application, by employing a brushless motor 12 and a planetary reducer 13 as power sources, can greatly improve the service life of the electric actuator, make it quieter during use, and improve the user experience for patients. Moreover, the planetary reducer 13 has a more compact structure and can achieve a higher rated output torque, thereby reducing the overall size of the electric actuator. At the same time, the planetary reducer makes the return backlash of the electric actuator small and improves the running accuracy. The encoder 14 can detect the rotation speed and angle of the tail shaft of the brushless motor 12. By calculating, the extension length of the actuator 24 can be known in real time, which allows for precise control of the extension length of the actuator 24. In conjunction with the zero-position detection sensor 15 to check whether the lead screw nut 23 has returned to the zero position, it can be reset to zero to avoid cumulative errors after long-term use, further improving the running accuracy of the electric actuator and enhancing the competitiveness of the product.

[0036] Preferably, the push rod 24 is sleeved on the outer surface of the lead screw 22, and the lead screw nut 23 is located at the end of the push rod 24 near the planetary reducer 13. Sleeving the push rod 24 on the outer surface of the lead screw 22 can make full use of space, making the overall structure of the electric push rod more compact.

[0037] Furthermore, a guide block (not shown in the figure) is provided on the outer side of the lead screw nut 23, and a sliding groove (not shown in the figure) is provided on the inner wall of the guide tube 21 to slide in conjunction with the guide block. By cooperating with the guide block and the sliding groove, the running trajectory of the lead screw nut 23 can be restricted, and the lead screw nut 23 can be prevented from shaking in the guide tube 21, thereby improving the accuracy of the extension and retraction of the push rod 24.

[0038] In one embodiment, the guide tube 21 is a square tube, and the cavity inside the guide tube 21 is also square. Correspondingly, the outer contour of the lead screw nut 23 is also square. The guide blocks are located at the four corners of the lead screw nut 23, and the sliding grooves are also located at the corners of the inner wall of the guide tube 21. It should be noted that the shape of the guide tube 21 can be freely set according to actual needs, and no specific limitation is made on the shape of the guide tube 21 here.

[0039] Preferably, the lead screw nut 23 is made of PEEK material. PEEK (polyetheretherketone) is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing and high mechanical strength. The lead screw nut 23 made of PEEK material is quieter and more durable than the traditional lead screw nut 23 made of brass material, which helps to extend the service life of the electric actuator.

[0040] In one embodiment, the telescopic mechanism 20 may further include a bearing 25 built into the housing 11. The bearing 25 is disposed at one end of the planetary reducer 13 near the lead screw 22, and the head of the lead screw 22 passes through the inner hole of the bearing 25. The bearing 25 can support the lead screw 22, prevent the lead screw 22 from deforming, and improve the fitting accuracy between the lead screw 22 and the lead screw nut 23.

[0041] As a further improvement to the above technical solution, a guide seat 26 is connected to the end of the guide tube 21 away from the outer casing 11. The guide seat 26 is provided with a guide hole that slides with the push rod 24. The guide seat 26 can provide support for the push rod 24, so that the push rod 24 can remain straight, while the guide hole can restrict the running trajectory of the push rod 24 and improve the accuracy of the extension and retraction of the push rod 24.

[0042] Optionally, to facilitate maintenance of the electric push rod, the guide seat 26 and the guide tube 21 can be detachably connected. The detachable connection between the guide seat 26 and the guide tube 21 can be achieved through snap-fit, interference fit, or fastener connection.

[0043] In one embodiment, an external connector 27 is provided at the end of the push rod 24 away from the planetary reducer 13. The external connector 27 is detachably connected to the push rod 24 by fasteners. By providing the external connector 27, it is easy to connect the push rod 24 to an external finger joint gripper. The detachable connection method allows for the replacement of different external connectors 27 as needed, resulting in better versatility.

[0044] Preferably, the fastener is a reamed screw. By connecting the outer connector 27 with the reamed screw, the rotation angle between the push rod 24 and the outer connector 27 is controllable, eliminating the need for an additional rotary connector and making installation and use more convenient.

[0045] like Figure 2As shown, the output end of the planetary reducer 13 is provided with a drive shaft 131. A protrusion 132 is provided at the end of the drive shaft 131 near the lead screw 22, and a groove is provided at the end of the lead screw 22 near the planetary reducer 13 to engage with the protrusion 132. The engagement of the protrusion 132 and the groove facilitates the connection between the lead screw 22 and the drive shaft 131, and this structure also provides strong load-bearing capacity, enabling high-speed, high-torque transmission.

[0046] It should be noted that the shape of the protrusion 132 and the groove is not limited to the structure shown in the attached figure, and the structure can be set according to actual needs.

[0047] Please refer to the following: Figure 2 The planetary reducer 13 includes a base 133, a cylinder 134, and multiple sets of planetary gears 135. The cylinder 134 is located at one end of the base 133 near the brushless motor 12. The number of planetary gear sets 135 can be increased or decreased according to actual needs. Each set of planetary gears 135 is built into the cylinder 134 along the axial direction of the cylinder 134. A gear ring is provided on the inner wall of the cylinder 134. The end of the drive shaft 131 away from the protrusion 132 passes through the base 133 and is fixedly connected to the planet carrier in the last planetary gear set 135. This makes the structure of the planetary reducer 13 more compact and helps to reduce the overall size of the electric actuator.

[0048] Each planetary gear set 135 includes a planet carrier, a sun gear, and several planetary gears. Each planetary gear is rotatably connected to the planet carrier and is spaced along the circumference of the sun gear on the planet carrier. Each planetary gear meshes with the corresponding sun gear and ring gear.

[0049] The electric push rod 100 used in the active and passive finger joint training system of this application also includes a controller (not shown). The controller is electrically connected to the brushless motor 12, the encoder 14 and the zero-position detection sensor 15 to control the electric push rod to operate according to a preset program or instruction.

[0050] The working principle of this application is as follows: The brushless motor 12 normally provides speed and torque to the lead screw 22 through the planetary reducer 13. The lead screw 22 rotates and is connected to the lead screw nut 23 through the threaded pair. The lead screw nut 23 is limited and guided by the guide tube 21, so the lead screw nut 23 moves linearly along the axial direction of the guide tube 21. The lead screw nut 23 is fixedly connected to the push rod 24, so that the push rod 24 can also move linearly along the axial direction of the guide tube 21. That is, the push rod 24 can extend or retract from the guide tube 21. The zero-position detection sensor 15 detects whether the lead screw nut 23 has returned to the zero position to avoid cumulative error. The encoder 14 is used to monitor the rotation angle of the brushless telescoping tail shaft. Through calculation, the extension length of the push rod 24 can be detected in real time to achieve precise control of the extension length of the push rod 24.

[0051] Finally, it should be noted that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A motorized pushrod for a finger joint passive training system, characterized by: The power mechanism (10) and the telescopic mechanism (20) are included. The power mechanism (10) includes a shell (11), a brushless motor (12) and a planetary reducer (13) which are respectively arranged in the shell (11), the brushless motor (12) is arranged at one end of the shell (11), the output shaft of the brushless motor (12) is in transmission connection with the planetary reducer (13), the tail shaft of the brushless motor (12) is provided with an encoder (14), and the planetary reducer (13) is provided with a zero position detection sensor (15) at the end away from the brushless motor (12). The telescopic mechanism (20) includes a guide pipe (21), a lead screw (22), a lead screw nut (23) and a push rod (24), the guide pipe (21) is connected to one end of the shell (11) close to the planetary reducer (13), one end of the lead screw (22) is connected with the output end of the planetary reducer (13), the other end of the lead screw (22) extends into the guide pipe (21) and is in threaded connection with the lead screw nut (23), the push rod (24) is arranged in the guide pipe (21), the lead screw nut (23) is in sliding connection with the guide pipe (21), and the lead screw nut (23) is fixedly connected with the push rod (24).

2. The electric push rod for the passive training system of the finger joint according to claim 1, characterized in that, The push rod (24) is arranged on the outer surface of the lead screw (22), and the lead screw nut (23) is arranged at one end of the push rod (24) close to the planetary reducer (13).

3. The electric push rod for the passive training system of the finger joint according to claim 1, characterized in that, The outer side of the lead screw nut (23) is provided with a guide block, and the inner wall of the guide pipe (21) is provided with a sliding groove in sliding connection with the guide block.

4. The electric push rod for the passive training system of the finger joint according to claim 1, wherein The material of the lead screw nut (23) is PEEK material.

5. The electric push rod for the passive training system of the finger joint according to claim 1, wherein The telescopic mechanism (20) further includes a bearing (25) arranged in the shell (11), the bearing (25) is arranged at one end of the planetary reducer (13) close to the lead screw (22), and the head of the lead screw (22) penetrates the inner hole of the bearing (25).

6. The electric push rod for the passive training system of the finger joint according to claim 1, wherein The end of the guide pipe (21) away from the shell (11) is connected with a guide seat (26), and the guide seat (26) is provided with a guide hole in sliding connection with the push rod (24).

7. The electric push rod for the passive training system of the finger joint according to claim 1, wherein The end of the push rod (24) away from the planetary reducer (13) is provided with an external connector (27), and the external connector (27) is detachably connected with the push rod (24) through a fastener.

8. The electric push rod for the passive training system of the finger joint according to claim 7, characterized in that, The fastener is a hinge hole screw.

9. The electrically powered push rod for the passive training system of the finger joint according to claim 1, characterized in that The output end of the planetary reducer (13) is provided with a transmission shaft (131), the end of the transmission shaft (131) close to the lead screw (22) is provided with a protrusion (132), and the end of the lead screw (22) close to the planetary reducer (13) is provided with a groove in embedding connection with the protrusion (132).

10. The electric push rod for the passive training system of the finger joint according to claim 9, characterized in that, The planetary reducer (13) comprises a base (133), a barrel (134) and a plurality of planetary gear sets (135), the barrel (134) is arranged at one end of the base (133) close to the brushless motor (12), each of the planetary gear sets (135) is arranged in the barrel (134) along the axial direction of the barrel (134), the inner wall of the barrel (134) is provided with a gear ring, and the end of the transmission shaft (131) away from the protrusion (132) is fixedly connected with a planet carrier in the last planetary gear set (135) after penetrating through the base (133).

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