A motor for a lawnmower track walking mechanism

Abstract

This application discloses a motor for a tracked walking mechanism of a lawnmower, including a motor shaft, a stator, a rotor, a front end cover and a housing rotatably connected to the motor shaft. The stator has a recessed cavity open towards the end face of the housing and a through groove axially penetrating the bottom of the recessed cavity. The recessed cavity is coaxial with the motor shaft. The rotor includes a cover housing sleeved outside the stator. A guide tube section extending axially into the recessed cavity is formed at the bottom of the cover housing. A countersunk hole coaxial with the guide tube section is formed at the outer end of the cover housing. An encoder is fixed at the bottom of the recessed cavity. A magnetic ring corresponding to the encoder is installed outside the guide tube section. The drive wheel of the reduction assembly includes a flange and a gear integrated together. The flange is accommodated and fixed in the countersunk hole. The gear meshes with an intermediate wheel to drive a gear ring installed on the inner wall of the housing to rotate the housing.

Description

Technical Field

[0001] This application relates to the field of drive motor technology, specifically a motor for a lawnmower track walking mechanism. Background Technology

[0002] The tracked walking mechanism of a lawnmower is a key component of the self-propelled lawnmower chassis system, used to support and enable the lawnmower to move. With the development of battery technology, tracked walking mechanisms driven by rechargeable power supplies and matching motors have made significant progress. However, the sensors used to measure the angular position and speed of the motor rotor are located on the shaft end, far from the rotor end face. Since the end face is greatly affected by leakage magnetic field, two solutions are usually adopted to reduce interference: one is to design the distance between the sensor and the rotor end face to be as large as possible, resulting in a long axial length of the entire motor, heavy weight, and difficulty in weight reduction; the other is to use a shielded structure, which leads to structural complexity. Therefore, it is necessary to further develop and solve the above problems. Utility Model Content

[0003] The purpose of this application is to provide a motor for a lawnmower track walking mechanism to solve the problems in the prior art.

[0004] To achieve the above objectives, this application provides the following technical solution: a motor for a lawnmower track walking mechanism, comprising a motor shaft, a stator, a rotor, a front end cover and a housing rotatably connected to the motor shaft, the front end cover and the housing forming a receiving cavity, the stator being fixedly mounted on the motor shaft and located within the receiving cavity, the rotor being located within the receiving cavity and rotatably mounted on the motor shaft in conjunction with the stator, and being connected to the housing via a reduction gear assembly, the stator having a recessed cavity open toward the end face of the housing and a through groove axially penetrating the bottom of the recessed cavity, the recessed cavity being coaxial with the motor shaft;

[0005] The rotor includes a cover housing sleeved outside the stator, the bottom of the cover housing having a guide tube section extending axially into the recessed cavity, and the outer end of the cover housing having a recessed countersunk hole coaxial with the guide tube section.

[0006] An encoder is fixed at the bottom of the cavity, and a magnetic ring corresponding to the encoder is installed on the outside of the guide section to enable the encoder to generate position and speed signals when the rotor rotates; a wire hole is provided on the motor shaft, and the wire is introduced into the wire hole and passes through the through slot to connect to the encoder and the coil on the stator respectively.

[0007] The drive wheel of the deceleration assembly includes a flange and a gear that are integrated together. The flange is housed and fixed in the countersunk hole. The gear meshes with the intermediate wheel and drives the gear ring installed on the inner wall of the housing to rotate the housing.

[0008] Furthermore, several connecting blocks are evenly distributed circumferentially in the middle of the outer wall of the housing for connecting with the toothed disc of the lawnmower's track walking mechanism.

[0009] Furthermore, the bottom ends of the front cover extend axially to form an oil seal position and a bearing position for installing an oil seal and a third bearing, respectively. The oil seal is located outside the receiving cavity, and the third bearing is located inside the receiving cavity.

[0010] Furthermore, the stator is provided with coil slots for winding the coil, and magnets matching the number of poles of the coil are evenly distributed on the inner wall of the housing.

[0011] Furthermore, a second bearing is installed on the inner wall of the guide tube section and the motor shaft. The second bearing has two bearings and is arranged at intervals along the axial direction of the motor shaft. The outer ring of the second bearing located at one end of the countersunk hole is axially limited and pressed by the end face of the flange.

[0012] Furthermore, the reduction assembly also includes a retainer fixedly mounted on the motor shaft, the intermediate wheel being rotatably mounted on the retainer, and the teeth of the drive wheel, the intermediate wheel, and the gear ring are all helical teeth.

[0013] Furthermore, the drive wheel, the intermediate wheel, and the gear ring are all made of 40Cr material.

[0014] Furthermore, there is an air gap between the inner wall of the cavity and the outer diameter of the encoder, and the width of the air gap is 8~9mm.

[0015] The beneficial technical effects of this application are as follows: The motor for the tracked walking mechanism of the lawnmower provided by this application has a recessed cavity on the stator, and the encoder and trigger magnetic ring used for detecting the rotor rotation position and speed are set inside the recessed cavity. In this way, the recessed cavity not only reduces the weight of the stator, but also keeps the encoder away from the magnetic poles of the magnets on the rotor, avoiding interference from leakage magnetic field, effectively improving the detection stability and reliability of the motor rotation signal, significantly improving the motor control accuracy, and making the control of the motor more sensitive and stable, which in turn helps to increase the output torque; and, it effectively shortens the axial length of the motor, making the motor structure more compact and easier to adapt to the tracked walking mechanism of the lawnmower. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of this application;

[0017] Figure 2 This is a perspective view of the present application;

[0018] Figure 3 A exploded view showing the connection relationship between the rotor and drive wheel of the motor used in the tracked walking mechanism of the lawnmower of this application;

[0019] Figure 4 This is a partial perspective view of this application;

[0020] Figure 5 This is a partial view of the stator of the motor used in the tracked walking mechanism of the lawnmower according to this application;

[0021] In the diagram: 1. Motor shaft; 101. Wire hole; 2. Oil seal; 3. Front cover; 4. Stator; 401. Through slot; 402. Coil slot; 403. Countersunk cavity; 5. Rotor; 501. Guide tube section; 502. Countersunk hole; 503. Cover housing; 6. Housing; 7. Hole retaining ring; 8. Shaft retaining ring; 9. Fourth bearing; 10. Intermediate gear; 11. Cage; 12. Drive gear; 1201. Gear section; 1202. Flange section; 13. First bearing; 14. Gear ring; 15. Second bearing; 16. Magnet; 17. Magnetic ring; 18. Encoder; 19. Third bearing; 20. Connecting block; 21. Wire; 22. Receiving cavity; 23. Air gap; 24. Positioning boss. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Please see Figure 1-5 A motor for a tracked walking mechanism of a lawnmower includes a motor shaft 1, a stator 4, a rotor 5, a front cover 3 rotatably connected to the motor shaft 1, and a housing 6. The front cover 3 and the housing 6 are connected to form a receiving cavity 22. The stator 4 is fixedly installed on the motor shaft 1 and located in the receiving cavity 22. The rotor 5 is located in the receiving cavity 22 and is paired with the stator 4. It is rotatably installed on the motor shaft 1 and is connected to the housing 6 through a reduction gear assembly. The stator 4 has a recessed cavity 403 open to the end face of the housing 6 and a through groove 401 axially penetrating the bottom of the recessed cavity 403. The recessed cavity 403 is coaxial with the motor shaft 1. In this embodiment, the housing 6 is rotatably connected to the motor shaft 1 through a first bearing 13. In this embodiment, the front cover 3 and the housing 6 are axially fastened by a stop provided on the front cover 3 and then sealed by fasteners. It is understood that a sealing ring is provided on the mating surface of the front cover 3 and the housing 6.

[0024] The rotor 5 includes a housing 503 sleeved outside the stator 4. The bottom of the housing 503 has a guide tube section 501 that extends axially into the recessed cavity 403. The outer end of the housing 503 has a recessed countersunk hole 502 that is coaxial with the guide tube section 501.

[0025] An encoder 18 is fixed at the bottom of the cavity 403. A magnetic ring 17 corresponding to the encoder 18 is installed on the outside of the guide tube section 501 to enable the encoder 18 to generate position and speed signals when the rotor 5 rotates. A wire hole 101 is provided on the motor shaft 1. The wire 21 is introduced through the wire hole 101 and passes through the through slot 401 to connect to the encoder 18 and the coil on the stator 4 respectively.

[0026] The drive wheel 12 of the reduction assembly includes a flange portion 1202 and a gear portion 1201 that are integrated together. The flange portion 1202 is housed and fixed in the countersunk hole 502. The gear portion 1201 meshes with the intermediate wheel 10 to drive the gear ring 14 installed on the inner wall of the housing 6 to rotate the housing 6.

[0027] With the above configuration, the motor for the tracked walking mechanism of the lawnmower provided in this application has a recessed cavity 403 on the stator 4. The encoder 18 and the trigger magnetic ring 17 used for detecting the rotational position and speed of the rotor 5 are placed inside the recessed cavity 403. In this way, the recessed cavity 403 not only reduces the weight of the stator 4, but also keeps the encoder 18 away from the magnetic poles of the magnet 16 on the rotor 5, avoiding interference from magnetic leakage to the encoder 18. This effectively improves the detection stability and reliability of the motor rotation signal, significantly improves the motor control accuracy, and makes the control of the motor more sensitive and stable, which in turn helps to increase the output torque. Furthermore, it effectively shortens the axial length of the motor, making the motor structure more compact and easier to adapt to the tracked walking mechanism of the lawnmower.

[0028] As a preferred embodiment, please refer to the following: Figures 1 to 5 Several connecting blocks 20 are evenly distributed around the middle of the outer wall of the housing 6 for connecting with the toothed disc of the lawnmower's track walking mechanism. Thus, in application, the part of the motor shaft 1 located at the outer end of the front cover 3 is installed on the object part of the lawnmower chassis, and the toothed disc of the lawnmower's track walking mechanism is fitted onto the positioning boss 24 of the connecting block 20 and connected to the threaded hole pre-set on the connecting block 20 by bolts, thereby serving as a drive wheel to drive the lawnmower to move.

[0029] As a preferred embodiment, please refer to the following: Figures 1 to 5The bottom ends of the front cover 3 extend axially to form oil seal positions and bearing positions for installing oil seal 2 and third bearing 19, respectively. Oil seal 2 is located outside the receiving cavity 22, and third bearing 19 is located inside the receiving cavity 22. This effectively prevents external dust and other impurities from entering the third bearing 19 and ensures the rotational flexibility of the front cover 3. It is understandable that a journal is provided on the motor shaft 1 to fix the inner ring of the third bearing 19. In this way, after the front cover 3 is connected to the housing 6, the inner rings of the third bearing 19 and the first bearing 13 are fixed on the motor shaft 1, thereby achieving axial positioning of the front cover 3 and housing 6 and enabling smooth rotation. When the motor shaft 1 is fixed to the object of the lawnmower chassis, the combination of the front cover 3 and housing 6 can rotate under the drive of the rotor 5.

[0030] As a preferred embodiment, please refer to the following: Figures 1 to 5 The stator 4 has a coil slot 402 for winding the coil. The inner wall of the housing 503 is evenly equipped with magnets 16 that match the number of coil poles. The wire 21 includes a conductive wire for inputting power to the coil and a signal for communication with the encoder 18. In this way, the signal from the encoder 18 is fed back to the motor driver, and the motor driver sends a controlled current to the coil, thereby forming a closed-loop control, which improves the control accuracy of the motor and makes the movement control of the lawnmower track more sensitive.

[0031] As a preferred embodiment, please refer to the following: Figures 1 to 5 The inner wall of the guide tube section 501 is fitted with a second bearing 15 to the motor shaft 1. There are two second bearings 15 arranged axially at intervals along the motor shaft 1. The outer ring of the second bearing 15 located at one end of the countersunk hole 502 is axially limited and pressed by the end face of the flange 1202. It can be understood that both ends of the inner wall of the guide tube section 501 have bearing positions for installing the second bearing 15. The outer ring of the other second bearing 15 away from the countersunk hole 502 can be fixed in the bearing hole of its bearing position by a retaining ring. The inner rings of the two second bearings 15 can be positioned on the motor shaft 1 by existing technologies such as corresponding journals or retaining rings on the motor shaft 1. In this way, the support stability of the rotor 5 is enhanced, the ability to resist axial load is improved, the rotational smoothness of the rotor 5 is improved, and the starting noise is effectively reduced.

[0032] As a preferred embodiment, please refer to the following: Figures 1 to 5The reduction assembly also includes a retainer 11 fixedly mounted on the motor shaft 1. The intermediate wheel 10 is rotatably mounted on the retainer 11. The teeth of the drive wheel 12, the intermediate wheel 10, and the gear ring 14 are all helical teeth. In this embodiment, three intermediate wheels 10 are evenly distributed and are respectively mounted on the support shaft of the retainer 11 through corresponding fourth bearings 9. The outer ring of the fourth bearing 9 is fixed in the bearing hole of the intermediate wheel 10 through a retaining ring 7, and the inner ring of the fourth bearing 9 is fixed on the journal of the support shaft through a retaining ring 8. The retainer 11 is fixedly connected to the motor shaft 1 through a flat key. Thus, when the coil on the stator 4 drives the rotor 5 to rotate, it drives the drive wheel 12 to rotate. The gear ring 14 can be rotated through the meshing intermediate wheel 10. In this embodiment, the gear ring 14 is an internal gear ring and is connected to the inner wall of the housing 6 at a predetermined position by a tight fit or laser welding.

[0033] As a preferred embodiment, please refer to the following: Figures 1 to 5 The drive wheel 12, intermediate wheel 10, and gear ring 14 are all made of 40Cr material. They undergo overall quenching and tempering treatment to enhance overall strength. High-frequency quenching or nitriding treatment can also be performed on each tooth surface to enhance tooth surface hardness, improve wear resistance and impact resistance, further reduce operating noise, and have a longer service life.

[0034] As a preferred embodiment, please refer to the following: Figures 1 to 5 An air gap 23 is provided between the inner wall of the cavity 403 and the outer diameter of the encoder 18. The width of the air gap 23 is 8~9mm. In this embodiment, the width of the air gap 23 is preferably 8.7mm. In this way, since it is far away from the magnetic influence area of ​​the magnet 16 on the inner wall of the rotor 5, the magnetic field interference of the magnet 16 is avoided. At the same time, the magnetic flux generated by the two adjacent coils on the stator 4 is closed in the magnetic circuit within the stator 4. The leakage magnetic flux is weak. In addition, the spacing effect of the air gap 23 also effectively avoids the interference of the coils to the encoder 18, ensuring the reliability and stability of the encoder 18. In this embodiment, the depth of the cavity 403 is 0.5~0.6 times the total axial thickness of the stator 4, preferably 0.57 times. In this way, sufficient connection length between the stator 4 and the motor shaft 1 can be guaranteed, thereby ensuring the connection strength between the stator 4 and the motor shaft 1 and ensuring the strength of the stator 4 itself, thus improving the overall reliability of the motor.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0036] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0037] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A motor for a tracked walking mechanism of a lawnmower, comprising a motor shaft (1), a stator (4), a rotor (5), a front end cover (3) rotatably connected to the motor shaft (1), and a housing (6), wherein the front end cover (3) and the housing (6) are connected to form a receiving cavity (22), the stator (4) is fixedly mounted on the motor shaft (1) and located within the receiving cavity (22), and the rotor (5) is located within the receiving cavity (22), paired with the stator (4), rotatably mounted on the motor shaft (1), and connected to the housing (6) via a reduction gear assembly, characterized in that: The stator (4) has a recessed cavity (403) that opens toward the end face of the housing (6) and a through groove (401) that axially penetrates the bottom of the recessed cavity (403). The recessed cavity (403) is coaxial with the motor shaft (1). The rotor (5) includes a cover (503) sleeved on the outside of the stator (4). The bottom of the cover (503) has a guide tube section (501) that extends axially into the recess (403). The outer end of the cover (503) has a recessed countersunk hole (502) that is coaxial with the guide tube section (501). An encoder (18) is fixed at the bottom of the recess (403), and a magnetic ring (17) corresponding to the encoder (18) is installed on the outside of the guide tube section (501) to enable the encoder (18) to generate position and speed signals when the rotor (5) rotates; a wire hole (101) is provided on the motor shaft (1), and the wire (21) is introduced through the wire hole (101) and passes through the through slot (401) to connect to the encoder (18) and the coil on the stator (4) respectively; The drive wheel (12) of the deceleration assembly includes a flange (1202) and a gear (1201) that are integrated together. The flange (1202) is housed and fixed in the countersunk hole (502). The gear (1201) meshes with the intermediate wheel (10) to drive the gear ring (14) installed on the inner wall of the housing (6) to rotate the housing (6).

2. The mower track motor according to claim 1, characterized in that: The outer wall of the casing (6) is provided with several connecting blocks (20) evenly distributed around the center, which are used to connect with the toothed disc of the lawnmower track walking mechanism.

3. The mower track motor of claim 1, wherein: The bottom ends of the front cover (3) extend axially to form oil seal positions and bearing positions for installing oil seal (2) and third bearing (19), respectively. The oil seal (2) is located outside the receiving cavity (22), and the third bearing (19) is located inside the receiving cavity (22).

4. The mower track motor of claim 1, wherein: The stator (4) has a coil slot (402) for winding the coil, and the inner wall of the housing (503) is evenly equipped with magnets (16) that match the number of poles of the coil.

5. The mower track motor of claim 1, wherein: The inner wall of the guide tube section (501) and the motor shaft (1) are equipped with a second bearing (15). There are two second bearings (15) arranged axially along the motor shaft (1). The outer ring of the second bearing (15) located at one end of the countersunk hole (502) is axially limited and pressed by the end face of the flange (1202).

6. The mower track motor of claim 1, wherein: The deceleration assembly also includes a retainer (11) fixedly mounted on the motor shaft (1), the intermediate wheel (10) being rotatably mounted on the retainer (11), and the teeth of the drive wheel (12), the intermediate wheel (10) and the gear ring (14) being helical teeth.

7. The mower track motor of claim 6, wherein: The drive wheel (12), the intermediate wheel (10), and the gear ring (14) are all made of 40Cr material.

8. The mower track motor of claim 1, wherein: There is an air gap (23) between the inner wall of the cavity (403) and the outer diameter of the encoder (18), and the width of the air gap (23) is 8~9mm.

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