Three-phase cycloid planetary reducer easy to install

Abstract

The three-phase cycloidal planetary reducer comprises eccentric shaft assemblies, cycloidal gears, a planet carrier and a pin wheel housing, the eccentric shaft assemblies are arranged in the circumferential direction of the planet carrier at intervals of 120 degrees, and each eccentric shaft assembly comprises an eccentric shaft, a falling-off type needle bearing and a second needle bearing. The eccentric shaft is provided with three sections of eccentric parts with the same eccentricity, the eccentric directions of the eccentric parts are distributed at intervals of 120 degrees, the eccentric part located in the middle is provided with a falling-off type needle bearing, and the eccentric parts located on the two sides are provided with second needle bearings; one end of the eccentric shaft is connected with a planetary gear through a spline; the eccentric shaft is connected with the planet carrier through a bearing; the cycloidal gear is in transmission connection with the eccentric shaft through a falling-off needle bearing or a second needle bearing at the corresponding position; the planet carrier is connected with the pin wheel housing through a main bearing; a roller pin is installed on the inner side of the pin wheel housing, and the cycloidal gear is meshed with the roller pin. The transmission mechanism has the advantages of being good in integrity, small in transmission error and convenient to assemble.

Description

Technical Field

[0001] The utility model relates to the technical field of reducers, in particular to a three-phase cycloid planetary reducer which is easy to install. Background Art

[0002] The existing RV reducer adopts a two-stage transmission mode. The first stage is an involute planetary gear transmission, and the second stage is a cycloidal pinwheel transmission. It consists of two cycloidal wheels installed at 180 degrees. Since there are only two cycloidal wheels, each cycloidal wheel is limited by the maximum contact stress. As a result, the reducer composed of two cycloidal wheels has a low load capacity, large vibration at high speeds, poor rigidity, unstable transmission, and a short life.

[0003] Existing Chinese invention patent application number 201410593953.3 discloses a three-piece cycloidal gear RV reducer, comprising a pinion housing, needle rollers, an output planetary carrier, three sets of planetary gears, an input shaft, three crankshafts fitted with steel sleeves, three cycloidal gears, an input planetary carrier, a first tapered roller bearing, a needle roller and retainer assembly, and a shoulder ring. Three cycloidal gears, each with a 120° phase difference, are hinged to the three crankshafts. The three cycloidal gears mesh with the needle rollers and are articulated to the three crankshafts via the needle roller and retainer assembly. The three sets of planetary gears are evenly spaced at 120° intervals. While maintaining a constant transmission ratio and minimizing the increase in width, the present invention achieves more uniform force distribution, smoother transmission, and minimal elastic backlash. It exhibits high precision, low noise, and strong load-bearing capacity.

[0004] In order to ensure that the three cycloid wheels can be installed on the crankshaft, the above scheme meets the installation requirements of the three cycloid wheels by installing a steel sleeve on the crankshaft. However, this approach makes the diameters of the three eccentric circles on the crankshaft different, resulting in a large transmission error during the operation of the reducer, which is inconvenient to assemble. In addition, this approach is not removable and cannot meet the high requirements of the roundness of the three eccentric circles and the circular runout of the axial end face. Utility Model Content

[0005] The utility model provides a three-phase cycloid planetary reducer which is easy to install and has the advantages of good integrity, small transmission error and easy assembly.

[0006] The technical problem to be solved is: by installing a steel sleeve on the crankshaft to meet the installation of the three cycloid wheels, but this approach makes the three eccentric circles on the crankshaft have different diameters, resulting in a large transmission error when the reducer is running and inconvenient assembly.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The utility model discloses a three-phase cycloid planetary reducer with simple installation, comprising an eccentric shaft assembly, a cycloid gear, a planetary carrier and a pinion housing. The eccentric shaft assembly is arranged at intervals of 120° along the circumferential direction of the planetary carrier, and comprises an eccentric shaft, a drop-out needle roller bearing and a second needle roller bearing. The eccentric shaft has three eccentric portions with the same eccentricity, and the eccentric directions of the eccentric portions are distributed at intervals of 120°. The drop-out needle roller bearing is installed on the eccentric portion in the middle, and the second needle roller bearings are installed on the eccentric portions on both sides; one end of the eccentric shaft is connected to the planetary gear via a spline;

[0009] The eccentric shaft is connected to the planetary carrier through a bearing; the cycloid wheel is connected to the eccentric shaft through a detachable needle roller bearing or a second needle roller bearing at the corresponding position; the planetary carrier is connected to the pinion housing through a main bearing; a needle roller is installed on the inner side of the pinion housing, and the cycloid wheel engages with the needle roller.

[0010] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the drop-out needle roller bearing comprises a retaining frame and a roller installed on the retaining frame.

[0011] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the diameter of the inner ring of the retaining frame is greater than the sum of the center distance between the two eccentric circles and the diameter of the eccentric circle.

[0012] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the eccentric shaft is connected to the planetary frame through a first needle roller bearing; the position where the first needle roller bearing is installed on the planetary frame is threadedly installed with an end cover.

[0013] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the cycloid wheels are three, and the phase difference between the three cycloid wheels is 120°.

[0014] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the main bearing is an angular contact ball bearing.

[0015] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, the cycloid wheel and the needle roller on the pinion housing are meshed with each other for at least half during the eccentric movement of the cycloid wheel.

[0016] The utility model provides a three-phase cycloid planetary reducer with simple installation. Furthermore, a tooth groove is provided on the inner side of the pin gear housing, and the needle roller is arranged in the tooth groove.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This application eliminates the use of a traditional steel sleeve on the eccentric shaft and sets the eccentric shaft as a complete component, ensuring the consistency of the diameters of the three eccentric circles on the eccentric shaft, which is consistent in processing, easy to assemble, and has small transmission errors during operation;

[0019] 2. By making the inner ring diameter of the frame larger than the sum of the center distance of the two eccentric circles and the diameter of the eccentric circles, and selecting the middle drop-out needle roller bearing and the needle roller bearings at both ends, the drop-out needle roller bearing in the middle can be installed along the axial direction of the eccentric shaft, which facilitates the installation of the drop-out needle roller bearing in the middle;

[0020] 3. By replacing the traditional tapered roller bearings connecting the eccentric shaft and the planetary carrier with needle roller bearings, and using end covers that cooperate with the planetary carrier threads to limit the axial position of the needle roller bearings, and by using needle roller bearings without bearing inner rings, the diameter of the eccentric shaft connected to it is increased, thereby improving the rigidity of the eccentric shaft; and needle roller bearings can arrange more rolling elements in a limited space, and the length of each rolling element is longer than that of equivalent tapered roller bearings, thereby improving the overall load-bearing capacity, avoiding interference installation of tapered roller bearings, and making installation simple and repeatable.

[0021] The present invention will be further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the explosion structure of the utility model;

[0023] Figure 2 This is a schematic diagram of the internal structure of the utility model;

[0024] Figure 3 This is a schematic structural diagram of the eccentric shaft of the utility model;

[0025] Figure 4 This is a schematic diagram of the structure of the cycloid wheel installation of the utility model.

[0026] Reference numerals:

[0027] 1. Eccentric shaft assembly; 1.1. Eccentric shaft; 1.2. Drop-out needle roller bearing; 1.3. Second needle roller bearing; 1.4. Eccentric portion; 1.5. Planetary gear; 1.6. Cage; 1.7. Roller; 2. Cycloidal gear; 3. Planetary carrier; 4. Pinion housing; 5. First needle roller bearing; 6. End cover; 7. Main bearing; 8. Needle roller. DETAILED DESCRIPTION

[0028] like Figure 1-Figure 4As shown, the utility model discloses a three-phase cycloid planetary reducer with simple installation, including an eccentric shaft assembly 1, a cycloid wheel 2, a planetary carrier 3 and a pinion housing 4. Three eccentric shaft assemblies 1 are arranged at intervals of 120° along the circumferential direction of the planetary carrier 3. The eccentric shaft assembly 1 is connected to the planetary carrier 3 through a first needle roller bearing 5. The position where the first needle roller bearing 5 is installed on the planetary carrier 3 is threadedly installed with an end cover 6 for axial positioning of the first needle roller bearing 5.

[0029] The eccentric shaft assembly 1 includes an eccentric shaft 1.1, a detachable needle roller bearing 1.2 and a second needle roller bearing 1.3. The eccentric shaft 1.1 has three eccentric parts 1.4 with the same eccentricity, and the eccentric directions of the eccentric parts 1.4 are evenly distributed at intervals of 120°, and can be distributed in sequence clockwise or counterclockwise; a detachable needle roller bearing 1.2 is installed on the middle eccentric part 1.4, and second needle roller bearings 1.3 are installed on the eccentric parts 1.4 at both ends. The first needle roller bearing 5 is assembled and connected to the eccentric shaft 1.1, and one end of the eccentric shaft 1.1 is connected to a planetary gear 1.5 via a spline, and the planetary gear 1.5 is used to engage with the input shaft.

[0030] The detachable needle roller bearing 1.2 includes a cage 1.6 and rollers 1.7. During installation, the cage 1.6 is installed first, and then the rollers 1.7 are installed one by one from the outer diameter direction of the cage 1.6 onto the cage 1.6. Then, the two second needle roller bearings 1.3, the first needle roller bearing 5 and the planetary gear 1.5 are installed from both sides of the eccentric shaft 1.1. To ensure that the inner ring diameter of the cage 1.6 is large enough, the cage 1.6 can be installed axially from the eccentric shaft 1.1. The diameter of the inner ring of the cage 1.6 is larger than the sum of the center distance of the two eccentric circles and the diameter of the eccentric circle, so that the cage 1.6 can be installed smoothly.

[0031] Three cycloid wheels 2 are provided with a phase difference of 120 degrees. The three cycloid wheels 2 are connected to the eccentric shaft 1.1 through the detachable needle roller bearings 1.2 or the second needle roller bearings 1.3 at the corresponding positions.

[0032] The planetary carrier 3 is connected to the pinion housing 4 through the main bearing 7. The main bearing 7 is an angular contact ball bearing. A tooth groove is provided on the inner side of the pinion housing 4. A needle roller 8 is provided in the tooth groove. The outer ring of the cycloid wheel 2 is swung and meshed with the needle roller 8. The cycloid wheel 2 and the needle roller 8 on the pinion housing 4 are partially meshed during the eccentric movement of the cycloid wheel 2.

[0033] The transmission principle is as follows:

[0034] In the first stage transmission, the input shaft meshes with the planetary gear 1.5 and transmits the rotational speed to the planetary gear 1.5 according to the gear ratio. The planetary gear 1.5 and the eccentric shaft 1.1 are spline-connected, so the rotational speed of the eccentric shaft 1.1 and the planetary gear 1.5 is equal.

[0035] In the second-stage transmission, the planetary gear 1.5 and the eccentric shaft 1.1 are converted into the input end of the second-stage transmission. The eccentric part 1.4 of the eccentric shaft 1.1 is connected to the cycloid wheel 2. The rotation of the eccentric shaft 1.1 drives the cycloid wheel 2 to perform eccentric motion. The inside of the fixed pinion housing 4 is arranged with equally spaced needle rollers 8, and the number of needle rollers 8 is one more than the number of teeth of the cycloid wheel 2, so that the cycloid wheel 2 performs a cycloid pinwheel transmission with a small tooth difference. The rotation of the cycloid wheel 2 is transmitted to the planetary carrier 3 through the eccentric shaft 1.1, and the planetary carrier 3 acts as the output end to achieve deceleration; the reduction ratio is the number of needle rollers 8, and the total reduction ratio is the product of the two-stage reduction ratios.

[0036] The embodiments described above are merely descriptions of preferred implementation methods of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A three-phase cycloid planetary reducer with simple installation, comprising an eccentric shaft assembly (1), a cycloid wheel (2), a planetary carrier (3) and a pinion housing (4), characterized in that: The eccentric shaft assembly (1) is arranged at intervals of 120° along the circumferential direction of the planetary carrier (3), and comprises an eccentric shaft (1.1), a drop-out needle roller bearing (1.2), and a second needle roller bearing (1.3); the eccentric shaft (1.1) is provided with three eccentric parts (1.4) with the same eccentricity; the eccentric directions of the eccentric parts (1.4) are distributed at intervals of 120°; the drop-out needle roller bearing (1.2) is installed on the eccentric part (1.4) located in the middle, and the second needle roller bearings (1.3) are installed on the eccentric parts (1.4) located on both sides; one end of the eccentric shaft (1.1) is connected to a planetary gear (1.5) via a spline; The eccentric shaft (1.1) is connected to the planetary carrier (3) through a bearing; the cycloid wheel (2) is connected to the eccentric shaft (1.1) through a detachable needle roller bearing (1.2) or a second needle roller bearing (1.3) at a corresponding position; the planetary carrier (3) is connected to the pinion housing (4) through a main bearing (7); a needle roller (8) is installed on the inner side of the pinion housing (4), and the cycloid wheel (2) is meshed with the needle roller (8).

2. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: The drop-out needle roller bearing (1.2) comprises a retaining frame (1.6) and a roller (1.7) mounted on the retaining frame (1.6).

3. The three-phase cycloid planetary reducer with simple installation according to claim 2, characterized in that: The diameter of the inner ring of the retainer (1.6) is greater than the sum of the center distance between the two eccentric circles and the diameter of the eccentric circle.

4. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: The eccentric shaft (1.1) is connected to the planet carrier (3) via a first needle roller bearing (5); an end cover (6) is threadedly mounted at the position where the first needle roller bearing (5) is mounted on the planet carrier (3).

5. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: The cycloid wheels (2) are three in number, and the phase difference between the three cycloid wheels (2) is 120°.

6. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: The main bearing (7) is an angular contact ball bearing.

7. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: The cycloid wheel (2) is meshed with the needle roller (8) on the pinion housing (4) for at least half of the eccentric movement of the cycloid wheel (2).

8. The three-phase cycloid planetary reducer with simple installation according to claim 1, characterized in that: A tooth groove is provided on the inner side of the needle gear housing (4), and the needle roller (8) is arranged in the tooth groove.

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