Combined type planetary gear transmission speed reducer

Abstract

The combined type planetary gear transmission speed reducer comprises an input shaft, a sun gear, a plurality of first planet gears, a first inner gear ring, a plurality of second planet gears, a second inner gear ring and an output shaft, the sun gear and the input shaft are coaxially arranged and driven by the input shaft, and the first planet gears are arranged on the outer side of the sun gear and are all externally meshed with the sun gear; the first inner gear ring is coaxially arranged on the outer side of the first planet gear and internally meshed with the first planet gear, the second planet gear and the first planet gear are coaxially arranged in the axial direction, the second inner gear ring is coaxially arranged on the outer side of the second planet gear and internally meshed with the second planet gear, the output shaft is connected with the second inner gear ring, and motion is input through the sun gear through the input shaft. The first planetary gear, the first inner gear ring and the second planetary gear are used for transmission, and finally output through the second inner gear ring and the output shaft. The invention provides a combined type planetary gear transmission speed reducer capable of eliminating a transmission gap.

Description

Technical Field

[0001] The invention belongs to the technical field of planetary reducers, and in particular relates to a compound planetary gear transmission reducer capable of eliminating transmission clearance. Background Art

[0002] Planetary reducers are widely used in power transmission units of robots, CNC machine tools and other equipment due to their compact structure, small size, large load capacity and low cost. Compound planetary gears can achieve a wide range of transmission ratios and high transmission efficiency through a certain ratio of teeth and optimized tooth shape design, and are widely used.

[0003] However, due to the inherent characteristics of its internal gears, there is a tooth side clearance when the gear teeth are meshed, which leads to the existence of reversing impact in the transmission mechanism, and the transmission accuracy and dynamic response performance are reduced, making it unsuitable for high-efficiency and precision transmission occasions. Therefore, how to eliminate the transmission clearance of the compound planetary reducer is an urgent problem to be solved. Summary of the invention

[0004] The main purpose of the present invention is to provide a compound planetary gear transmission reducer capable of eliminating transmission clearance, thereby overcoming the deficiencies of traditional reducers in terms of transmission efficiency and transmission accuracy.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: a compound planetary gear transmission reducer capable of eliminating transmission clearance, comprising: Input shaft; a sun gear, which is coaxially arranged with the input shaft and driven by the input shaft; A plurality of first planetary gears are arranged outside the sun gear and mesh with the sun gear externally; A first inner gear ring, coaxially disposed on the outer side of the first planetary gear and meshing with the first planetary gear; A plurality of second planetary gears are axially coaxially arranged on a planetary gear shaft with the first planetary gears; A second inner gear ring, coaxially disposed on the outer side of the second planetary gear and internally meshing with the second planetary gear; An output shaft connected to the second inner gear ring; The sun gear, the first planetary gear, the first inner gear ring, the second planetary gear and the second inner gear ring are all herringbone gears; The motion is input through the input shaft via the sun gear, transmitted through the first planetary gear, the first internal gear ring and the second planetary gear, and finally output through the second internal gear ring via the output shaft.

[0006] In a preferred embodiment, the first planetary gear and the second planetary gear coaxial therewith are axially displaced, so that the first planetary gear is in close contact with the sun gear and the first inner gear ring, and the second planetary gear is in close contact with the second inner gear ring.

[0007] In a preferred embodiment, elastic members for adjusting the preload force of the tooth surface are provided at both axial ends of the planetary gear shaft.

[0008] In a preferred embodiment, the reducer further comprises an axial driving structure connected to the planetary gear shaft, and the first planetary gear and the second planetary gear are driven by the axial driving structure to generate axial displacement.

[0009] In a preferred embodiment, the axial drive structure is an adjustment bolt and / or a linear transmission mechanism, and the linear transmission mechanism includes a linear motor.

[0010] In a preferred embodiment, the reducer also includes a housing, the input shaft is connected to the housing for relative rotation, the first inner ring gear is fixed to the inner side of the housing, and the second inner ring gear is arranged inside the housing and is connected to the housing for relative rotation; and / or, the reducer also includes a first planetary carrier for mounting the first planetary gear and a second planetary carrier for mounting the second planetary gear, the axial ends of the planetary gear shaft are respectively connected to the first planetary carrier and the second planetary carrier for relative rotation, and the first planetary carrier and the second planetary carrier are connected to the input shaft for relative rotation.

[0011] In a preferred embodiment, the input shaft and the sun gear are integral, and / or the first planetary gear and the second planetary gear adopt a coaxial integral structure, and / or the second inner gear ring and the output shaft are integral, and / or the input shaft and the output shaft are connected for relative rotation.

[0012] In a preferred embodiment, the herringbone teeth are all herringbone teeth with the same module and number of teeth but opposite helix angles.

[0013] In a preferred embodiment, the input shaft and the housing, the second inner gear ring and the housing, the planetary gear shaft and the first planet carrier and the second planet carrier, and the first planet carrier and the second planet carrier and the input shaft are all connected for relative rotation via bearings.

[0014] In a preferred embodiment, the reducer includes a plurality of sets of planetary gears, and each set of planetary gears includes at least one of the first planetary gears and at least one of the second planetary gears axially coaxially arranged on the planetary gears.

[0015] Compared with the prior art, the beneficial effects of the present invention are at least: 1. The present invention adopts a combination design of two sets of inner gear rings + planetary gears, and adopts a form in which the inner gear ring on one side is fixed and the inner gear ring on the other side is output, so that the planet carrier does not transmit force, improves the force condition of the reduction mechanism, and is easier to arrange the anti-backlash mechanism on the planet carrier, thereby achieving a good anti-backlash effect; and the composite planetary reducer proposed by the present invention adopts herringbone gear transmission, so no axial force is generated inside, thereby improving its bearing capacity.

[0016] 2. The present invention adopts the axial displacement method to change the axial position of the planetary gear, so that the planetary gear and the sun gear and the gear teeth on both sides of the inner gear ring are simultaneously pressed against each other on opposite sides, eliminating the transmission gap during forward and reverse transmission, and improving its transmission accuracy and transmission efficiency.

[0017] 3. The present invention arranges springs on both sides of the planetary gear shaft end, and uses the spring force to adjust the tooth surface clearance-eliminating preload force, thereby achieving adaptive elimination of the constant clearance and the time-varying clearance, and improving the precision retention of the reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a compound planetary gear transmission reducer in one embodiment of the present invention; Figure 2 is a schematic diagram of the structure of an input shaft + sun gear in one embodiment of the present invention; Figure 3 is a schematic diagram of the structure of a set of planetary gears in one embodiment of the present invention; Figure 4 is a schematic structural diagram of a first internal gear ring in one embodiment of the present invention; Figure 5 is a schematic structural diagram of a second internal gear ring in one embodiment of the present invention; Figure 6a It is a schematic diagram of the gear teeth on both sides of the first planetary gear and the gear teeth on both sides of the first inner gear ring being simultaneously pressed against opposite sides in one embodiment of the present invention; Figure 6b It is a schematic diagram of the sun gear and the first planet gear being pressed against each other at the same time on opposite sides in one embodiment of the present invention; Figure 6c It is a schematic diagram of a second planetary gear having two side teeth in one embodiment of the present invention being in close contact with two side teeth of the second inner gear ring at the same time.

[0020] Reference numerals: 1. Housing, 2. Input shaft, 3. Sun gear, 4. First planetary gear, 5. First inner ring gear, 6. Second planetary gear, 7. Second inner ring gear, 8. Output shaft, 9. Bearing, 10. First planet carrier, 11. Planetary gear shaft, 12. Second planet carrier, 13. Adjusting screw, 14. Elastic member. DETAILED DESCRIPTION

[0021] The present invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are only exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as limiting, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in virtually any appropriate detailed embodiment.

[0022] like Figure 1 As shown, a compound planetary gear transmission reducer disclosed in an embodiment of the present invention includes a housing 1, an input shaft 2, a sun gear 3, a plurality of first planetary gears 4, a first inner ring gear 5, a plurality of second planetary gears 6, a second inner ring gear 7 and an output shaft 8. When working, the motion is input through the input shaft 2 through the sun gear 3, transmitted through the first planetary gear 4, the first inner ring gear 5 and the second planetary gear 6, and finally output through the second inner ring gear 7 through the output shaft 8.

[0023] Among them, combined Figure 1 and Figure 2 As shown, one end of the input shaft 2 extends into the housing 1 and is connected to the output shaft 8, and the other end extends out of the housing 1 and is rotatably connected to the housing 1, specifically, it can be rotatably connected through a bearing 9. The sun gear 3 is located in the housing 1 and is coaxially arranged with the input shaft 2 and rotates synchronously with the output shaft 8 under the drive of the input shaft 2. In this embodiment, the sun gear 3 is preferably designed as an integral unit with the input shaft 2, and the sun gear 3 uses herringbone teeth with the same module number of teeth and opposite helix angle directions.

[0024] The plurality of first planetary gears 4 are all arranged on the outside of the sun gear 3 and mesh with the sun gear 3. In this embodiment, the first planetary gears 4 also use herringbone teeth with the same module number of teeth and opposite helix angles, that is, the first planetary gears 4 mesh with the sun gear 3 through herringbone teeth, and the plurality of first planetary gears 4 are all mounted on a first planet carrier 10, which is rotatably connected to the input shaft 2, and can be rotatably connected through a bearing 9.

[0025] Combination Figure 1 and Figure 4As shown, the first inner gear ring 5 is coaxially arranged on the outer side of the first planetary gear 4 and meshes with the first planetary gear 4. In this embodiment, the first inner gear ring 5 is fixed in the housing 1, and its inner side also adopts herringbone teeth with the same module, number of teeth and opposite helix angle directions, so as to mesh with the outer side of the first planetary gear 4 through the herringbone teeth.

[0026] The plurality of second planetary gears 6 are coaxially arranged on a planetary gear shaft 11 with the first planetary gear 4, and rotate synchronously with the first planetary gear 4. In this embodiment, like the first planetary gear 4, the second planetary gear 6 also adopts herringbone gears with the same module, number of teeth and opposite helix angles. Figure 1 and Figure 3 As shown, a second planetary gear 6 and a first planetary gear 4 are axially coaxially arranged on a planetary gear shaft 11, and the three constitute a set of planetary gears. Multiple sets of planetary gears, such as at least two sets of planetary gears, can be arranged on the outer side of the sun gear 3. The planetary gear shaft 11, the first planetary gear 4 and the second planetary gear 6 of each set of planetary gears are designed as an integrated structure. And the multiple second planetary gears 6 are also installed on a second planetary carrier 12, and the second planetary carrier 12 is also rotatably connected to the input shaft 2, and can be rotatably connected through bearings 9. And the axial ends of each planetary gear shaft 11 are respectively rotatably connected to the first planetary carrier 4 and the second planetary carrier 6, and can be rotatably connected through bearings 9.

[0027] Combination Figure 1 and Figure 5 As shown, the second inner gear ring 7 is coaxially arranged on the outer side of the second planetary gear 6 and meshes with the second planetary gear 6. In this embodiment, the second inner gear ring 7 is arranged inside the housing 1 and is connected to the housing 1 for relative rotation, so as to rotate synchronously under the drive of the second planetary gear 6, and can also be connected to rotate via the bearing 9. Similar to the first inner gear ring 5, the inner side of the second inner gear ring 7 also adopts herringbone teeth with the same module number of teeth and opposite helix angle directions, so as to mesh with the outer side of the second planetary gear 6 through herringbone teeth.

[0028] The output shaft 8 is connected to the second inner gear ring 7 and rotates synchronously with the second inner gear ring 7. In this embodiment, the output shaft 8 is integrally designed with the second inner gear ring 7, and the output shaft 8 is rotatably connected to the input shaft 2, and can be rotatably connected via a bearing 9.

[0029] In the present invention, the sun gear 3, the first planetary gear 4, the first inner gear ring 5, the second planetary gear 6 and the second inner gear ring 7 are all designed with a herringbone gear layout, and the axial forces generated by each meshing pair offset each other, thereby optimizing the force conditions and improving the load-bearing capacity of the reducer.

[0030] Preferably, combined Figure 6a , 6bAs shown in Figures 6 and 6c, in order to eliminate the transmission clearance of the reducer, the first planetary gear 4 and the coaxial second planetary gear 6 are axially displaced, so that the two side teeth of the first planetary gear 4 are simultaneously pressed against the two side teeth of the sun gear 3 and the first inner gear ring 5 on opposite sides, and the two side teeth of the second planetary gear 6 are simultaneously pressed against the two side teeth of the second inner gear ring 7 on opposite sides, thereby eliminating the transmission clearance of the reducer during forward and reverse transmission, and improving its transmission accuracy, planetary gear load balancing performance and transmission efficiency. In implementation, there are many ways to make the first planetary gear 4 and the second planetary gear 6 axially displaced. In a specific embodiment, an adjustment screw 13 connected to the planetary gear shaft 11 is provided on a side surface of the first planet carrier 10, and the first planetary gear 4 and the second planetary gear 6 are axially displaced by the adjustment screw 13, so that the two side teeth of the first planetary gear 4 are simultaneously pressed against the two side teeth of the sun gear 3 and the first inner gear ring 5 on opposite sides, and the two side teeth of the second planetary gear 6 are simultaneously pressed against the two side teeth of the second inner gear ring 7 on opposite sides, thereby eliminating the transmission clearance of the reducer during forward and reverse transmission. In other embodiments, the axial displacement may be achieved by using a linear motor or other linear transmission mechanisms.

[0031] In addition, preferably, elastic members 14 are provided at both axial ends of the planetary gear shaft 11 to adjust the preload force of the tooth surface contact, ensuring that not only the constant transmission clearance but also the time-varying transmission clearance can be eliminated, so as to achieve adaptive elimination of the transmission clearance and improve the precision maintenance performance of the reducer, the load-balancing performance of the planetary gear and the reliability. In a specific embodiment, the elastic member 14 is implemented by, but not limited to, a spring.

[0032] The present invention has the following advantages: 1. The present invention adopts a combination design of two sets of inner gear rings + planetary gears, and adopts the form of fixing the inner gear ring on one side and outputting the inner gear ring on the other side, so that the planet carrier does not transmit force, improves the force conditions of the reduction mechanism, and is easier to arrange the anti-backlash mechanism on the planet carrier, thereby achieving a good anti-backlash effect; and the composite planetary reducer proposed by the present invention adopts herringbone gear transmission, so no axial force is generated inside, thereby improving its bearing capacity. 2. The present invention adopts the axial displacement method to change the axial position of the planetary gear, so that the planetary gear and the two sides of the sun gear and the inner gear ring are simultaneously pressed against the opposite sides, eliminating the transmission clearance during forward and reverse transmission, and improving its transmission accuracy and transmission efficiency. 3. The present invention arranges springs on both sides of the planetary gear shaft end, and the spring force is used to adjust the tooth surface anti-backlash preload, so as to achieve adaptive elimination of constant clearance and time-varying clearance, thereby improving the accuracy retention of the reducer.

[0033] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0034] The use of headings and sections in this disclosure is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the disclosure.

Claims

1. A compound planetary gear transmission reducer, characterized in that: The reducer comprises: Input shaft; a sun gear, which is coaxially arranged with the input shaft and driven by the input shaft; A plurality of first planetary gears are arranged outside the sun gear and mesh with the sun gear externally; A first inner gear ring, coaxially disposed on the outer side of the first planetary gear and meshing with the first planetary gear; A plurality of second planetary gears are axially coaxially arranged on a planetary gear shaft with the first planetary gears; A second inner gear ring, coaxially disposed on the outer side of the second planetary gear and internally meshing with the second planetary gear; An output shaft connected to the second inner gear ring; The sun gear, the first planetary gear, the first inner gear ring, the second planetary gear and the second inner gear ring are all herringbone gears; The motion is input through the input shaft via the sun gear, transmitted through the first planetary gear, the first internal gear ring and the second planetary gear, and finally output through the second internal gear ring via the output shaft.

2. A compound planetary gear transmission reducer according to claim 1, characterized in that: The first planetary gear and the second planetary gear coaxial therewith generate axial displacement, so that the first planetary gear, the sun gear and the first inner gear ring, and the second planetary gear and the second inner gear ring are all in close contact.

3. The compound planetary gear transmission reducer according to claim 1, characterized in that: Elastic parts for adjusting the pre-tightening force of the tooth surface are arranged at both axial ends of the planetary gear shaft.

4. A compound planetary gear transmission reducer according to claim 2, characterized in that: The reducer further comprises an axial driving structure connected to the planetary gear shaft, and the first planetary gear and the second planetary gear are driven by the axial driving structure to generate axial displacement.

5. A compound planetary gear transmission reducer according to claim 4, characterized in that: The axial driving structure is an adjusting bolt and / or a linear transmission mechanism, and the linear transmission mechanism includes a linear motor.

6. The compound planetary gear transmission reducer according to claim 1, characterized in that: The reducer also includes a housing, the input shaft is connected to the housing for relative rotation, the first inner ring gear is fixed to the inner side of the housing, and the second inner ring gear is arranged inside the housing and is connected to the housing for relative rotation; and / or, the reducer also includes a first planet carrier for mounting the first planetary gear and a second planet carrier for mounting the second planetary gear, the axial ends of the planetary gear shaft are respectively connected to the first planet carrier and the second planet carrier for relative rotation, and the first planet carrier and the second planet carrier are connected to the input shaft for relative rotation.

7. The compound planetary gear transmission reducer according to claim 1, characterized in that: The input shaft and the sun gear are integral, and / or the first planetary gear and the second planetary gear are coaxial and integral, and / or the second inner gear ring and the output shaft are integral, and / or the input shaft and the output shaft are connected for relative rotation.

8. The compound planetary gear transmission reducer according to claim 1, characterized in that: The herringbone teeth are all herringbone teeth with the same module, number of teeth and opposite helix angle directions.

9. The compound planetary gear transmission reducer according to claim 6, characterized in that: The input shaft and the housing, the second inner gear ring and the housing, the planetary gear shaft and the first planet carrier and the second planet carrier, and the first planet carrier and the second planet carrier and the input shaft are all connected for relative rotation via bearings.

10. The compound planetary gear transmission reducer according to claim 1, characterized in that: The reducer includes a plurality of sets of planetary gears, and each set of planetary gears includes at least one of the first planetary gears and at least one of the second planetary gears axially coaxially arranged on the planetary gears.

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