Cycloidal Pinwheel Pair with Uniform Contact and One-tooth Difference
Disclosed is a cycloidal pinwheel pair with uniform contact and one-tooth difference, comprising a stator and a rotor. Each gear tooth profile of the rotor has a modified recess provided symmetrically on both sides; the starting point (A) of the modified recess on one side of the gear tooth profile is located between a first point and a second point determined by locations of two limit positions, the end point (B) of the modified recess on the same side of the gear tooth profile is located between a third point and a fourth point determined by locations of two limit positions. By adopting the present disclosure, the internal leakage formed between high and low pressure chambers is effectively avoided, thereby significantly improving the volume efficiency and mechanical efficiency. Meanwhile, the present disclosure is extremely simple in structure and can be molded by one-time grinding with better manufacturability.
This application claims priority to Chinese Application No. 201110378546.7, “Cycloidal Pinwheel Pair with Uniform Contact and One-tooth Difference”, filed on Nov. 24, 2011, which is hereby incorporated by reference in its entirety.
TECHNICAL FIELDThe present disclosure relates to a cycloidal pinwheel pair, and more particularly to a cycloidal pinwheel pair with uniform contact and one-tooth difference, belonging to the technical fields of cycloidal hydraulic motors and fully hydraulic diverters.
BACKGROUND ARTA cycloidal pinwheel pair with one-tooth difference has advantages such as compact structure, high kinematic precision, low noise, high tooth strength, strong bearing capacity, little junction surface friction, high transmission efficiency, higher power density, and so on. Therefore, it is widely used in products such as cycloid hydraulic motors with large torque and low speed, fully hydraulic diverters, cycloid pumps, and so on.
As shown in
The US patent U.S. Pat. No. 7,481,633 disclosed a cycloidal pinwheel pair with modified profile, wherein, the original cycloidal profile of the cycloidal pinwheel is modified to have discontinuous concaves according to a certain regularity, so that in the transmission process when the cycloidal pinwheel is meshing with the pin teeth of the stator, the errors are compensated by the concaves instead, without the need of reserving the clearance. Its advantage is that the concave segments can only enable communication between adjacent chambers having similar hydraulic pressure, without causing internal leakage between chambers having larger pressure differentials; therefore, it is benefit for keeping the operation steady and for improving the volume efficiency and mechanical efficiency. Moreover, after the cycloidal pinwheel is modified, the meshing contact of the cycloidal pinwheel is decreased, which is benefit for reducing the transmission resistance and hydraulic pulsation. However, this technical solution employs too many concave segments, as a result, it is complex in structure, tedious in design and calculation, and difficult to produce.
SUMMARY OF THE INVENTIONIn view of the defects existing in the prior art, an object of the present disclosure is to provide a cycloidal pinwheel pair with uniform contact and one-tooth difference, which is capable of avoiding internal leakage, improving volume efficiency and mechanical efficiency, and which has simple structure and better manufacturability, on the premise of maintaining the original structure parameters of the cycloidal pinwheel pair of hydraulic components unchanged.
Researches show that, when the cycloidal pinwheel pair is in movement (as shown in
In order to realize the object mentioned above, the present disclosure provides a cycloidal pinwheel pair with uniform contact and one-tooth difference, comprising a stator having pin teeth in interval distribution, and a rotor having gear teeth meshing with the pin teeth of the stator, and each gear tooth profile of the rotor has a modified recess provided symmetrically on both sides; wherein,
a starting point of said modified recess on one side of the gear tooth profile is located between a first point and a second point: when a predetermined pin tooth locates nearest to a meshing instant center, a first meshing point, formed by a pin tooth locating farthest to said meshing instant center and a corresponding gear tooth meshing therewith on a same side, is the first point; and when the predetermined pin tooth locates farthest to said meshing instant center, a second meshing point, formed by an adjacent pin tooth and a corresponding gear tooth meshing therewith on a same side, is the second point;
an end point of the modified recess is located between a third point and a fourth point: when the predetermined pin tooth locates nearest to said meshing instant center, a third meshing point, formed by an adjacent pin tooth and a corresponding gear tooth meshing therewith on the same side, is the third point; and when the predetermined pin tooth locates farthest to said meshing instant center, a fourth meshing point, formed by a pin tooth locating nearest to the meshing instant center and a corresponding gear tooth meshing therewith on the same side, is the fourth point.
Experiments indicate that it is optimal when the starting point of the modified recess is located midway between the first point and the second point, and the end point of the modified recess is located midway between the third point and the fourth point.
Preferably, said modified recess is an equi-depth recess of gear tooth profile of a standard cycloidal pinwheel, and a depth of said modified recess is between 0.03 mm and 0.008 mm, preferably 0.012 mm.
By adopting the present disclosure, in the transmission process, the adjacent high pressure chambers communicate with each other, and the adjacent low pressure chambers also communicate with each other, thereby forming a transition chamber between the high pressure chamber and the low pressure chamber to realize pressure transition. Since the present disclosure adopts the modified recess to replace the conventional clearance designed for error compensation, the internal leakage formed between high and low pressure chambers is effectively avoided, thereby significantly improving the volume efficiency and mechanical efficiency. Meanwhile, the present disclosure is extremely simple in structure and can be molded by one-time grinding with better manufacturability. Moreover, at the meshing clearance generated by the modified recess on the high pressure chamber and on the low pressure chamber, oil film filled with hydraulic oil is formed, which is benefit for reducing the friction of the kinematic pair, improving the flexibility of the movement, and reducing the requirement of machining precision.
The present disclosure will be described in further details with the accompanying drawings.
o' represents the center of the rotor;
P represents the meshing instant center (meshing pitch point);
o1, o2, o3, o4, o5, o6, o7 respectively represent the centers of the pin teeth (centers of the chambers);
11, 12, 13, 14, 15, 16, 17, and 22, 23, 24, 25, 26, 27 respectively represent the theoretical meshing contact points;
A, B, C, D respectively represent the profile modified points;
Embodiment one:
The structure of the cycloidal pinwheel pair with uniform contact and one-tooth difference according to embodiment one is as shown in
As shown in
As shown in
Since each gear tooth profile of the rotor has the symmetrical modified recesses on both sides, the modified recess on the other side can be determined once the modified recess on one side is determined.
In order to simplify the process, the modified recess is an equi-depth recess of gear teeth profile of a standard cycloidal pinwheel, the depth of the modified recess is between 0.03 mm and 0.008 mm, and an optimal depth is 0.012 mm. Preferably, the transition between the bottom of the modified recess and the starting point A, and the transition between the bottom of the modified recess and the end point B, are both smooth arc transitions (as shown in
During operation as shown in
The cycloidal pinwheel pair with uniform contact and one-tooth difference always maintains three-point meshing contact in movement, therefore, its movement is more flexible and the stress is more steady; and the oil film is formed between the adjacent chambers, thereby improving the pressure bearing capacity between meshing pairs, which is beneficial for improving the stress distribution in movement. Moreover, the present disclosure adopts the modified recess to replace the conventional clearance designed for error compensation, thereby dramatically reducing the internal leakage which easily occurs between high and low pressure chambers when the loading capacity is too high in the prior art, thereby significantly improving the volume efficiency and the mechanical efficiency. Experience has proven that, according to the cycloidal pinwheel pair with uniform contact and one-tooth difference of this embodiment, the machining process of the rotor is simpler, the meshing movement is more flexible, thereby improving the efficiency, and prolonging the life time. By adopting the present disclosure, the production cost is reduced, and the overall reliability of the product is improved.
In addition to the embodiment mentioned above, the present disclosure may have other implementation manners, for example, the teeth number of the cycloidal pinwheel pair may be 5 pin teeth with 4 gear teeth, or more; and the configuration of the cycloidal pinwheel teeth may be either assembled or integrated, and so on. Various modifications and replacements may be made therein without departing from the theory of the present disclosure, which should also be seen in the scope of the present disclosure.
Claims
1. A cycloidal pinwheel pair with uniform contact and one-tooth difference, comprising a stator with pin teeth in interval distribution, and a rotor having gear teeth meshing with the pin teeth of said stator, and each gear tooth profile of the rotor has a modified recess provided symmetrically on both sides; wherein,
- a starting point of said modified recess on one side of the gear tooth profile is located between a first point and a second point: when a predetermined pin tooth locates nearest to a meshing instant center, a first meshing point, formed by a pin tooth locating farthest to said meshing instant center and a corresponding gear tooth meshing therewith on a same side, is the first point; and when the predetermined pin tooth locates farthest to said meshing instant center, a second meshing point, formed by an adjacent pin tooth and a corresponding gear tooth meshing therewith on a same side, is the second point;
- an end point of the modified recess is located between a third point and a fourth point:
- when the predetermined pin tooth locates nearest to said meshing instant center, a third meshing point, formed by an adjacent pin tooth and a corresponding gear tooth meshing therewith on the same side, is the third point; and when the predetermined pin tooth locates farthest to said meshing instant center, a fourth meshing point, formed by a pin tooth locating nearest to the meshing instant center and a corresponding gear tooth meshing therewith on the same side, is the fourth point.
2. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 1, wherein, the starting point of said modified recess is located midway between the first point and the second point.
3. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 2, wherein, the end point of said modified recess is located midway between the third point and the fourth point.
4. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 3, wherein, said modified recess is an equi-depth recess of the gear tooth profile of a standard cycloidal pinwheel.
5. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 4, wherein, a depth of said modified recess is between 0.03 mm and 0.008 mm.
6. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 5, wherein, a transition between a bottom of the modified recess and the starting point, and a transition between the bottom of the modified recess and the end point, are both smooth arc transitions.
7. The cycloidal pinwheel pair with uniform contact and one-tooth difference according to claim 4, wherein, a depth of said modified recess is 0.012 mm.
Type: Application
Filed: Oct 9, 2012
Publication Date: Feb 19, 2015
Inventors: Zhisheng Wang (District Zhenjiang), Aiguang Weng (District Zhenjiang), Zhimin Zhang (District Zhenjiang), Liqun Ji (District Zhenjiang), Feng Lou (District Zhenjiang)
Application Number: 14/359,549
International Classification: F04C 2/10 (20060101); F04C 18/10 (20060101);