Planetary gear reducer

Abstract

The invention relates to a planetary gear reducer which comprises a reduction gear set, the reduction gear set comprises a sun gear fixedly connected with the output end of a motor, a planetary gear carrier and a shell sleeve fixed to the motor, and the shell sleeve is of an annular inner gear ring structure. The reduction gear set further comprises a plurality of planetary gears fixedly arranged on the planetary gear carrier, the planetary gears are evenly distributed in the circumferential direction of the center gear, each planetary gear is meshed with the center gear and the inner gear ring structure of the outer shell sleeve, and the planetary gear carrier is connected with the outer shell sleeve in a relative rotating mode through a bearing. By the adoption of the technical scheme, the output shaft of the motor is directly and fixedly connected with the center gear, a traditional coupling structure is omitted, axial space is reserved for series connection of follow-up multi-stage speed reduction sets, the problem that the transmission stage number is limited is solved, the shell sleeve is integrated with the annular inner gear ring structure, the assembly error of a traditional split type gear ring is avoided, and the assembly efficiency is improved. And the structural strength and meshing precision of the gear ring are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a planetary gear reducer. Background Art

[0002] Planetary gear reducer is a kind of precision reduction device widely used in the field of industrial transmission. Its core structure consists of sun gear, planetary gear, planet carrier and ring gear. It realizes high reduction ratio, large torque output and compact space layout through multi-stage gear meshing. Traditional planetary gear reducer usually adopts single-stage or two-stage reduction structure, but in occasions requiring higher reduction ratio or more complex power distribution, such as robot joints and electric vehicle drive systems, existing reducers often have problems such as complex structure, insufficient transmission efficiency or excessive axial size.

[0003] The reduction ratio of single-stage or two-stage planetary gear reducers is limited, and it is difficult to meet the needs of a wide range of speed regulation. In addition, in multi-stage reducers, the alignment and bearing support requirements of each stage of the gear set are strict. The existing structure often relies on high-precision processing, which increases manufacturing costs. Summary of the invention

[0004] Purpose of the invention: In order to overcome the defects of the prior art, the present invention provides a planetary gear reducer, which connects multiple stages of driven gear sets in series and realizes rapid expansion through tooth keyway connection to meet different reduction ratio requirements, thereby solving the problem of limited reduction ratio of single-stage or double-stage planetary gear reducers.

[0005] The technical solution of the present invention is as follows: a planetary gear reducer includes a motor and a reduction gear set, wherein the reduction gear set includes a central gear fixedly connected to the output end of the motor, a planetary gear carrier and an outer shell fixed to the motor, wherein the outer shell is in the form of an annular inner gear ring structure, and the reduction gear set also includes a plurality of planetary gears fixedly arranged on the planetary gear carrier, wherein the planetary gears are evenly distributed around the central gear, and each planetary gear is meshed with the central gear and the inner gear ring structure of the outer shell, and the planetary gear carrier and the outer shell are connected for relative rotation via bearings.

[0006] By adopting the above technical solution, the traditional coupling structure is eliminated through the direct fixed connection between the motor output shaft and the center gear, and axial space is reserved for the subsequent series connection of multi-stage reduction groups, solving the problem of limited transmission stages. The structural design of the annular inner gear ring integrated in the outer shell avoids the assembly error of the traditional split gear ring, improves the structural strength and meshing accuracy of the gear ring, and ensures the control of the reduction ratio through the inner gear ring structure of the outer shell and the tooth number ratio of the center gear.

[0007] A further configuration of the present invention includes a driven gear set, each driven gear set includes a driven central gear, a driven gear frame, and a plurality of driven planetary gears fixedly arranged on the driven gear frame, each driven planetary gear is meshed with the driven central gear and the inner gear ring structure of the outer shell, the driven planetary gears are evenly distributed on the circumference of the driven central gear, the driven central gear is fixedly connected to the planetary gear frame, and the driven gear frame and the outer shell are connected for relative rotation via bearings.

[0008] By further adopting the above-mentioned setting, a driven gear set is set, and the driven central gear is fixed to and driven by the planetary gear frame, so that after the motor drives the central gear to rotate, the planetary gear frame rotates to drive the driven central gear to rotate, and drive the driven gear frame to rotate, so that after being decelerated by the reduction gear set, it is further decelerated by the driven gear set, thereby increasing the number of transmission stages.

[0009] The present invention is further configured as follows: the number of the driven gear set is at least one, the planetary gear frame and the driven gear frame are both provided with a tooth keyway at one end away from the motor, one end of the driven center gear is embedded in the tooth keyway and fixed, and the other end extends to the center of the driven gear frame.

[0010] By further adopting the above-mentioned configuration, multiple driven gear sets are provided, and the driven center gear of each driven gear set can be snapped onto the gear rack of the previous level to realize power transmission, increase the number of transmission stages, and increase the reduction ratio more smoothly. At the same time, the driven center gear is directly used as a key and inserted into the tooth keyway, without the need for additional parts to cooperate and connect, thereby reducing the probability of failure.

[0011] The present invention is further configured as follows: the planetary gear frame and the driven gear frame both include a base, a support column and a cover plate; a center hole is provided in the center of the base for the center gear or the driven center gear to pass through; a plurality of grooves are provided on the base for accommodating planetary gears or driven planetary gears; each groove and the cover plate are provided with through holes; each support column is a cylindrical structure with a diameter smaller at both ends than in the middle; the two ends of the support column are respectively clamped in the through holes on the groove and the cover plate; a planetary gear or a driven planetary gear is fixedly provided in the middle of the support column.

[0012] By further adopting the above arrangement, a split base-support column-cover plate combined structure is adopted, which can ensure strength while reducing weight and optimize the axial movement of the gears. At the same time, the stepped shaft design of the support column realizes a plug-and-lock assembly method, which can improve assembly efficiency.

[0013] The present invention is further configured as follows: the cover plate and the base are in a circular structure, the cover plate is fixedly arranged on the end surface of the base away from the motor, the tooth keyway is arranged at the center of the cover plate, and the tooth keyway is in a through hole structure.

[0014] With the above further arrangement, the cover plate and the base are circular in structure, which is convenient for sleeve connection of the bearing.

[0015] A further configuration of the present invention is that the outer shell may be a segmented structure.

[0016] With the above-mentioned further arrangement, since the gear speeds in the reduction gear set and different driven gear sets are different, their wear and heat generation are different. The segmented outer shell can be made of different materials to adapt to different heating conditions, which can effectively increase the service life while controlling the cost. At the same time, the shorter outer shell is easier and simpler when it is mounted outside the bearing.

[0017] A further configuration of the present invention is that the cover plate is provided with a countersunk hole for connecting an external device.

[0018] With the above further configuration, countersunk holes are preset on the cover plate, and external equipment can be connected through connecting structures such as bolts, thereby enabling the reducer to be used.

[0019] A further configuration of the present invention is as follows: the motor comprises a rotating shaft, a non-output end of the motor is provided with an inwardly concave embedding hole, an encoder is provided in the embedding hole, and the encoder is directly or indirectly coaxially connected to the rotating shaft.

[0020] By adopting the above-mentioned further configuration, by setting an embedded hole at the non-output end of the motor, the overall axial dimension can be significantly reduced, the encoder can be avoided from protruding externally, and a coaxial connection between the encoder and the rotating shaft can be achieved, thereby avoiding the inertia delay of the intermediate transmission components, shortening the control loop response time corresponding to the encoder, and being able to more accurately control the motor output.

[0021] The present invention is further provided with a plug cover in the embedding hole for sealing the encoder in the embedding hole, and the rear end surface of the plug cover is flush with the non-output end surface of the motor.

[0022] By further configuring the above, the embedded hole is sealed by a plug cover, which can effectively prevent dust and water from entering and extend the service life; and the rear end face of the plug cover is flush with the non-output end face of the motor, which can prevent it from protruding outward and being hit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of a specific embodiment of the present invention; Figure 2 It is a schematic diagram of the overall structure of the hidden outer shell in a specific embodiment of the present invention; Figure 3 It is a schematic diagram of the overall structure of the reduction gear set and its outer bearing in a specific embodiment of the present invention; Figure 4 It is a schematic diagram of the overall structure of the driven gear set and its outer bearing in a specific embodiment of the present invention; Figure 5 It is a schematic diagram of the overall structure of the motor and part of the reduction gear set in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of hiding the outermost cover plate in a specific embodiment of the present invention; Figure 7 It is a schematic diagram of the overall structure of the outer shell in a specific embodiment of the present invention; Figure 8 It is a schematic diagram of the overall structure of the base in a specific embodiment of the present invention; Fig. 9 It is a schematic diagram of the overall structure of the cover plate in a specific embodiment of the present invention; Fig.10 It is a schematic diagram of the overall structure of the support column in a specific embodiment of the present invention; Fig.11 It is a schematic diagram of the position of the plug cover on the motor in a specific embodiment of the present invention; Fig.12 It is a schematic diagram of the explosion structure in a specific embodiment of the present invention.

[0024] In the figure: 1. Motor; 2. Reduction gear set; 21. Center gear; 22. Planetary gear; 23. Planetary gear carrier; 24. Outer shell; 3. Driven gear set; 31. Driven center gear; 32. Driven planetary gear; 33. Driven gear carrier; 4. Bearing; 5. Tooth keyway; 6. Base; 7. Support column; 8. Cover plate; 9. Center hole; 10. Countersunk groove; 11. Through hole; 12. Rotating shaft; 13. Embedded hole; 14. Encoder; 15. Plug cover. DETAILED DESCRIPTION

[0025] The technical scheme in this embodiment will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0026] It should be noted that in the description of the present invention, all directional indications (such as up, down, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] In addition, in the present invention, the descriptions such as "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. In the description of the present invention, the meaning of "several" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0028] In addition, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by those skilled in the art. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] like Figure 1-12 As shown, a planetary gear reducer includes a motor 1 and a reduction gear set 2, wherein the motor 1 includes a rotating shaft 12, and the reduction gear set 2 includes a central gear 21 fixedly connected to the output end of the rotating shaft 12 in the motor 1, a planetary gear carrier 23, and an outer shell 24 fixed to the motor 1, wherein the outer shell 24 is a circular columnar structure with an inner gear ring structure inside, and the reduction gear set 2 also includes three planetary gears 22 fixedly arranged on the planetary gear carrier 23, wherein the planetary gears 22 are evenly distributed at equal angles on the circumference of the central gear 21, and each planetary gear 22 is meshed with the central gear 21 and the inner gear ring structure of the outer shell 24, and the planetary gear carrier 23 and the outer shell 24 are connected for relative rotation through a bearing 4, so that the planetary gear carrier 23 is supported, and the rotation axis is controlled to be the same as the bearing 4.

[0030] Specifically, the direct fixed connection drive between the output shaft of the motor 1 and the center gear 21 eliminates the traditional coupling structure, reserves axial space for the subsequent series connection of multi-stage reduction groups, solves the problem of limited transmission levels, and the structural design of the integrated annular inner gear ring in the outer shell 24 avoids the assembly error of the traditional split gear ring, improves the structural strength and meshing accuracy of the gear ring, and ensures the control of the reduction ratio through the gear ratio of the inner gear ring structure of the outer shell 24 and the center gear 21. In this embodiment, the inner gear ring structure of the outer shell 24 adopts a gear with sixty teeth and the center gear 21 adopts a gear with twelve teeth to obtain a precise reduction ratio.

[0031] The present embodiment also includes a driven gear set 3, which includes a driven central gear 31, a driven gear frame 33, and a plurality of driven planetary gears 32 fixedly arranged on the driven gear frame 33. The present embodiment adopts three driven planetary gears 32, which is the same as the number of planetary gears 22. The three driven planetary gears 32 are distributed at equal angles on the circumference of the driven central gear 31. Each driven planetary gear 32 is meshed with the driven central gear 31 and the inner gear ring structure of the outer shell 24. The driven planetary gears 32 are evenly distributed on the circumference of the driven central gear 31. The driven central gear 31 is fixedly connected to the planetary gear frame 23. The driven gear frame 33 is connected to the outer shell 24 for relative rotation through a bearing 4, and the driven gear frame 33 is supported, and the rotating axis is controlled to be the same as the bearing 4. By controlling the cylindricity of the outer shell 24, the coaxial state of the planetary gear frame 23 and the driven gear frame 33 can be achieved.

[0032] Therefore, by setting a driven gear set 3, and fixing and driving the driven central gear 31 to the planetary gear carrier 23, the motor 1 drives the central gear 21 to rotate, and then the planetary gear 22 rotates on the outer shell 24 to realize the rotation of the planetary gear carrier 23. Since the driven central gear 31 is fixed to the planetary gear carrier 23, the rotation action of the driven central gear 31 is realized, and the driven planetary gear 32 rotates on the outer shell 24, thereby driving the driven gear carrier 33 to rotate, so as to drive the rotation of the subsequent connected equipment. In summary, after being decelerated by the reduction gear set 2, it is further decelerated by the driven gear set 3 to increase the transmission stage. The gear ratio of the inner ring gear structure of the outer shell 24 and the driven central gear 31 is used to ensure the control of the deceleration ratio. In this embodiment, the inner ring gear structure of the outer shell 24 adopts a gear with sixty teeth and the central gear 24 adopts a gear with twelve teeth, so as to realize further precise deceleration after the reduction gear set 2 is decelerated.

[0033] The number of the driven gear sets 3 can be multiple. In the present embodiment, the number of the driven gear sets 3 is four. The driven central gear 31 of the latter stage is fixed to the driven gear frame 33 of the previous stage, so that the driven central gear 31 of the latter stage is driven to rotate by the driven gear frame 33 of the previous stage, so that the driven gear frame 33 of the latter stage rotates until the driven gear frame 33 of the last stage rotates. Furthermore, the planetary gear frame 23 and the driven gear frame 33 at one end away from the motor 1 are provided with a tooth keyway 5, one end of the driven central gear 31 is embedded in the tooth keyway 5 and fixed, and the other end extends to the center of the driven gear frame 33, while the outermost driven gear set 3 does not need to be provided with a tooth keyway 5, thereby reducing the probability of external debris entering.

[0034] By setting up multiple driven gear sets 3, the driven center gear 31 of each driven gear set 3 can be snapped onto the gear rack of the previous level to achieve power transmission, increase the number of transmission stages, and increase the reduction ratio more smoothly. At the same time, the driven center gear 31 is directly inserted into the tooth keyway 5 as a key without the need for additional parts to cooperate and connect, thereby reducing the probability of failure.

[0035] There are gaps between adjacent driven central gears 31 and between the driven central gear 31 and the central gear 21 to avoid the problems of resistance and wear caused by contact when different central gears rotate.

[0036] Furthermore, in the present embodiment, the planetary gear frame 23 and the driven gear frame 33 have the same structure, both including a base 6, a support column 7 and a cover plate 8. The overall structure adopts a split base-support column-cover plate combination structure, which can reduce weight while ensuring strength. Bearings 4 are arranged on the periphery of the cover plate 8 and the end of the base 6 away from the cover plate 8, so that the bearings 4 are located on both sides of the gear frame and can be better and more stably supported in the outer shell 24. A center hole 9 is provided in the center of the base 6 for the center gear 21 or the driven center gear 31 to pass through, and a plurality of grooves 10 are provided on the base 6 for accommodating the planetary gears 22 or the driven planetary gears 32, so that the planetary gears 22 or the driven planetary gears 32 extend out of the corresponding side wall of the gear frame and contact and mesh with the inner gear ring of the outer shell 24.

[0037] Each support column 7 is a cylindrical structure with a smaller diameter at both ends than in the middle. A through hole 11 is provided on each sink 10 and the cover plate 8. Both ends of the support column 7 are respectively engaged with the through holes 11 on the sink 10 and the cover plate 8. Thus, the support column 7 is in the shape of a stepped shaft. By inserting the through hole 11, a plug-and-lock assembly is achieved, thereby improving assembly efficiency. A planetary gear 22 or a driven planetary gear 32 is fixedly provided in the middle of the support column 7. It should be noted that the planetary gear 22 and the driven planetary gear 32 are both planetary gears in a planetary gear set, which is a common prior art, and are respectively fixed on the support column 7 at the corresponding sink 10.

[0038] Furthermore, the cover plate 8 is provided with countersunk holes for connecting external equipment. Through the preset countersunk holes, the external equipment can be connected through connecting structures such as bolts, thereby enabling the reducer to be used.

[0039] The cover plate 8 and the base 6 are circular in structure, which is convenient for sleeve-fitting the bearing 4 and facilitating installation. The cover plate 8 is fixedly arranged on the end surface of the base 6 away from the motor 1. The tooth keyway 5 is arranged at the center of the cover plate 8 and can penetrate the entire cover plate 8 to form a through-hole structure.

[0040] The outer shell 24 can be a segmented structure. After using multiple sets of driven gear sets 3, the overall length is longer, and it is more difficult to install the bearing 4 in the outer shell 24. The installation is easier and simpler. Since the gear speeds of the reduction gear set 2 and different driven gear sets 3 are different, their wear and heat generation are different. The segmented outer shell 24 can use different materials to adapt to different heating conditions, which can effectively increase the service life while controlling the cost. At the same time, the shorter outer shell 24 is when it is sleeved outside the bearing 4.

[0041] In this embodiment, the motor 1 can adopt a servo motor with an encoder 14, wherein an inwardly concave embedding hole 13 is provided on the end face of the non-output end of the motor 1, and the encoder 14 is arranged in the embedding hole 13. The embedding hole 13 is provided on the end face of the non-output end of the motor 1 to place the encoder 14, which can significantly reduce the overall axial size and avoid the encoder 14 from protruding outward. The encoder 14 is coaxially connected with the rotating shaft 12, which can avoid the inertia delay of the intermediate transmission components, shorten the control loop response time corresponding to the encoder 14, and can more accurately control the output of the motor 1. It should be noted that the encoder 14 and the rotating shaft 12 can be directly fixedly connected, or they can be fixedly connected indirectly by a coupling. It is only necessary to place the encoder 14 in the embedding hole 13. In this embodiment, the encoder 14 is directly fixedly connected to the rotating shaft 12 to avoid errors caused by backlash, elastic deformation or installation deviation that may exist when indirectly connected by a coupling or gear.

[0042] The encoder 14 is an existing mature technology. After being coaxially connected with the rotating shaft 12, it can measure and feedback the position, speed and rotation direction of the motor rotor. The user can adjust and compensate for the error of the reducer by setting the encoder 14 to control the output rate more accurately. At the same time, the encoder 14 also has a temperature control module that can monitor the motor temperature and alarm. The temperature control module is a mature technology, and the internal circuit principle is not introduced in detail.

[0043] A plug cover 15 for sealing the encoder 14 in the embedding hole 13 is provided on the embedding hole 13. By sealing the embedding hole 13 with the plug cover 15, dust and water can be effectively prevented from entering, thereby extending the service life. The plug cover 15 can be stuck in the embedding hole 13, or a snap-fit ​​structure can be provided on the plug cover 15 or the embedding hole 13 to fix the two. The rear end face of the plug cover 15 is flush with the non-output end face of the motor 1, which can avoid protruding outward and being hit.

[0044] The encoder 14 also has a temperature detection function, which can monitor the motor temperature and alarm. This function can monitor the operating temperature of the motor in real time. Once the temperature of the motor 1 exceeds the preset safety threshold, the system will immediately trigger the alarm mechanism to remind the user to pay attention and take corresponding measures. This design can not only effectively prevent the motor 1 from being damaged due to overheating, but also ensure the continuous and stable operation of the production line, and improve production efficiency and safety.

Claims

1. A planetary gear reducer, comprising a motor (1), characterized in that: The invention also comprises a reduction gear set (2), the reduction gear set (2) comprising a central gear (21) fixedly connected to the output end of the motor (1), a planetary gear carrier (23), and an outer shell (24) fixed to the motor (1), the outer shell (24) being in the form of an annular inner gear ring structure, the reduction gear set (2) further comprising a plurality of planetary gears (22) fixedly arranged on the planetary gear carrier (23), the planetary gears 22 being evenly distributed in the circumferential direction of the central gear (21), each planetary gear (22) being meshed with the central gear (21) and the inner gear ring structure of the outer shell (24), and the planetary gear carrier (23) and the outer shell (24) being connected for relative rotation via a bearing (4).

2. A planetary gear reducer according to claim 1, characterized in that: The invention also comprises a driven gear set (3), each driven gear set (3) comprising a driven central gear (31), a driven gear frame (33), and a plurality of driven planetary gears (32) fixedly arranged on the driven gear frame (33), each driven planetary gear (32) meshing with the driven central gear (31) and the inner gear ring structure of the outer shell (24), the driven planetary gears (32) being evenly distributed in the circumferential direction of the driven central gear (31), the driven central gear (31) being fixedly connected to the planetary gear frame (23), and the driven gear frame (33) being rotatably connected to the outer shell (24) via a bearing (4).

3. A planetary gear reducer according to claim 2, characterized in that: The number of the driven gear set (3) is at least one, and the ends of the planetary gear frame (23) and the driven gear frame (33) away from the motor (1) are both provided with a tooth keyway (5), and one end of the driven central gear (31) is embedded in the tooth keyway (5) for fixation, and the other end extends to the center of the driven gear frame (33).

4. A planetary gear reducer according to claim 3, characterized in that: The planetary gear carrier (23) and the driven gear carrier (33) both comprise a base (6), a support column (7) and a cover plate (8); a center hole (9) for a center gear (21) or a driven center gear (31) to pass through is provided at the center of the base (6); a plurality of sinks (10) for accommodating planetary gears (22) or driven planetary gears (32) are provided on the base (6); each sink (10) and the cover plate (8) are provided with a through hole (11); each support column (7) is a cylindrical structure with two ends having a smaller diameter than the middle; the two ends of the support column (7) are respectively clamped to the sink (10) and the through hole (11) on the cover plate (8); and a planetary gear (22) or a driven planetary gear (32) is fixedly provided at the middle of the support column (7).

5. A planetary gear reducer according to claim 4, characterized in that: The cover plate (8) and the base (6) are of circular structure; the cover plate (8) is fixedly arranged on the end surface of the base (6) away from the motor (1); the tooth keyway (5) is arranged at the center of the cover plate (8); and the tooth keyway (5) is of a through hole structure.

6. A planetary gear reducer according to claim 4, characterized in that: The cover plate (8) is provided with a countersunk hole for connecting external equipment.

7. A planetary gear reducer according to claim 2, characterized in that: The outer shell (24) may be a segmented structure.

8. The planetary gear reducer according to claim 1, characterized in that: The motor (1) comprises a rotating shaft (12). A concave embedding hole (13) is provided on a non-output end surface of the motor (1). An encoder (14) is provided in the embedding hole (13). The encoder (14) is coaxially connected to the rotating shaft (12).

9. A planetary gear reducer according to claim 8, characterized in that: The embedding hole (13) is provided with a plug cover (15) for sealing the encoder (14) in the embedding hole (13), and the rear end surface of the plug cover 15 is flush with the non-output end surface of the motor (1).

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