Eccentric rotor expansion machine and rotating assembly and cavity structure thereof

Abstract

The invention belongs to the field of positive displacement expansion machines, particularly relates to an eccentric rotor expansion machine and a rotating assembly and a cavity structure thereof, and aims to solve the problems that existing equipment is high in machining and assembling difficulty, limited in rotating speed power and prominent in friction and leakage loss. An inner ring of a driving bearing is fixed to the eccentric wheel, and an outer ring of the driving bearing is fixed to the inner wall of a rotor, so that the rotor is eccentric, the outer wall of the rotor is tangent to the inner wall of the stator, the matching structure is simplified, and friction is reduced; in the cavity structure, a sliding groove and a cylindrical cavity are formed in the stator in the circumferential direction, blades are arranged in the sliding groove in a sliding mode, the ends of the blades make contact with the rotor, a built-in linear spring provides continuous pressure so that the blades can be tightly attached to the rotor, and roller pin rows on the two sides of the sliding groove achieve guiding limiting and reduce friction. Through structural optimization, the machining and assembling difficulty is reduced, the air cavity sealing performance is improved, high-rotating-speed operation is adapted, friction and leakage losses are reduced, the power output interval is widened, and the energy conversion efficiency and operation stability of the expansion machine are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the technical field of volumetric expanders, and particularly relates to an eccentric rotor expander and its rotating components and cavity structure. Background Technology

[0002] An eccentric rotor expander is a positive displacement expander. Its basic principle is to convert the pressure energy of a fluid into mechanical energy by utilizing the periodic expansion process of the working medium within a closed chamber. This type of expander typically consists of a stator, an eccentrically positioned rotor, and several blades. Driven by springs and other elements, one end of each blade remains in contact with the outer wall of the rotor, thus dividing the annular space between the stator and rotor into multiple independent air chambers. As the rotor rotates, each air chamber sequentially undergoes the processes of intake, expansion, and exhaust, achieving continuous and stable power output.

[0003] In existing eccentric rotor expander structures, such as the Chinese patent application with application number 2024101226032, the rotor typically achieves eccentric setting and motion transmission through multiple mating structures, including a drive disc and drive bearing. While this design enables the rotor to revolve and rotate, it also brings significant drawbacks: First, the complex mating relationships of multiple parts require extremely high machining precision, leading to increased manufacturing costs and assembly difficulties; second, the multiple mechanical contact interfaces generate significant frictional losses at high speeds, reducing overall machine efficiency; furthermore, to ensure continuous contact between the blades and the rotor's outer wall, spiral springs are used to provide clamping force. However, spiral springs are not standard parts, have a low upper limit to the torque they can provide, and struggle to maintain sufficient clamping force at high speeds, easily causing the blades to disengage from the rotor, resulting in air chamber seal failure, reduced efficiency, and even limiting the expander's operating speed and output power.

[0004] On the other hand, in the existing structure, the blade shaft often needs to pass through the stator housing and be connected to the external spiral spring. This through structure destroys the sealing integrity of the cavity, which can easily cause leakage of the working medium, resulting in additional energy loss and potentially affecting the stability and reliability of the expander operation.

[0005] Therefore, there is an urgent need for an eccentric rotor expander structure that is simplified, easy to process and assemble, can adapt to higher speeds, and has lower friction and leakage losses, in order to improve its working efficiency, operational reliability and power output range. Summary of the Invention

[0006] In view of this, the present invention aims to provide an eccentric rotor expander and its rotating components and cavity structure to solve the technical problems of existing eccentric rotor expanders, such as high processing and assembly difficulty, limited operating speed and power, friction and leakage of working medium.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A rotating assembly of an eccentric rotor expander includes: The rotating shaft coincides with the axis of the stator, and an eccentric wheel is provided on the rotating shaft; The rotor is eccentrically positioned inside the stator. The drive bearing has its inner ring fixed to the eccentric wheel and its outer ring fixedly connected to the inner wall of the rotor. Under the limiting action of the drive bearing, the outer wall of the rotor is tangent to the inner wall of the stator, so that the rotor always maintains a preset eccentricity relative to the shaft.

[0008] Furthermore, the drive bearing is a rolling bearing.

[0009] Furthermore, the number of drive bearings is at least one, and they are arranged at axial intervals along the shaft.

[0010] Furthermore, the eccentric wheel and the rotating shaft are integrally formed.

[0011] Furthermore, the outer ring of the drive bearing is fixed with an interference fit to the inner wall of the rotor, and the inner ring of the drive bearing is fixed with an interference fit to the outer wall of the eccentric wheel.

[0012] A cavity structure for an eccentric rotor expander, comprising: The stator has N radially extending grooves evenly distributed along its circumference and N cylindrical cavities corresponding to and connected to each groove, where N is an integer greater than or equal to 3; stator end caps are provided on both sides along the axial direction of the stator. The blades are N in number, each blade is slidably disposed in a corresponding groove, and one end of each blade is in contact with the outer wall surface of the rotor as described in claim 1; The spring assembly includes a linear spring, which is located entirely within a cylindrical cavity and is always in a compressed state. One end of the linear spring is fixed, and the other end abuts against the blade to drive the blade to press against the outer wall of the rotor. Two adjacent blades, rotor, stator, and stator end caps on both sides of the axis form a variable volume air chamber. The resultant force generated by the high-pressure gas acting on the outer wall of the rotor forms a torque relative to the shaft through the eccentricity.

[0013] Furthermore, the cavity structure also includes a needle roller array, which is arranged on both sides of the slide groove. The needle rollers of the needle roller array protrude from the side wall of the slide groove and roll in contact with the side of the blade to guide and limit the blade.

[0014] Furthermore, the spring assembly also includes a spring support and a spring end cap. The spring support is fixedly connected to the end of the blade away from the rotor. The spring end cap is fixedly mounted on the stator and closes the end of the cylindrical cavity. One end of the linear spring is connected to the spring support, and the other end of the linear spring is connected to the spring end cap.

[0015] Furthermore, the linear spring is a cylindrical helical compression spring.

[0016] An eccentric rotor expander includes the aforementioned rotating assembly and the aforementioned cavity structure.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: 1. This invention employs a structure in which the drive bearing directly connects the eccentric wheel of the rotating shaft to the inner wall of the rotor. This design eliminates the complex multiple mating mechanisms between the rotor, drive disc, and drive bearing, significantly simplifying the structure of the rotating assembly. On the one hand, this reduces the stringent requirements for the precision of parts machining, making manufacturing and assembly simpler and more economical; on the other hand, by utilizing the low-friction characteristics of the relative rolling of the inner and outer rings of the drive bearing, the dynamic friction loss during the rotor's revolution around the shaft is effectively reduced, improving the mechanical transmission efficiency.

[0018] 2. This invention abandons the traditional spiral spring and adopts a mature and standardized linear spring to drive the blades. The linear spring provides stable and sufficiently large axial force, ensuring that the blades reliably remain in contact with the rotor outer wall even when the expander is running at high speed. This breaks the limitations of the original structure on speed and power, widens the effective working range of the expander, and reduces the probability of blade detachment and functional failure due to insufficient spring mechanical properties, thus improving the reliability and stability of the equipment operation.

[0019] 3. The linear spring and related spring supports, end caps, and other components of this invention are fully integrated into the cylindrical cavity inside the stator, eliminating the need for the blade shaft to be extended outside the housing and connected to the spring, as is the case in traditional structures. This concealed design eliminates the potential leakage path caused by the shaft penetrating the stator housing, significantly enhancing the sealing integrity of the working gas chamber. Therefore, it effectively reduces internal leakage losses of the high-pressure working medium, contributing to improved volumetric efficiency and energy conversion efficiency of the expander.

[0020] 4. This invention incorporates needle roller rows on both sides of the slide groove as a guiding mechanism. When the blade reciprocates within the slide groove, the needle rollers of the row make rolling contact with the sides of the blade. This firstly transforms the sliding friction between the blade and the slide groove into rolling friction, further reducing motion resistance and friction loss. Secondly, the needle roller rows on both sides effectively limit and guide the blade, preventing it from tilting or deflecting during movement, thus avoiding the risk of jamming within the slide groove and ensuring the smooth and stable long-term operation of the expander. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the rotating assembly of the eccentric rotor expander described in the embodiment of the present invention; Figure 2 A schematic diagram of the cavity structure of the eccentric rotor expander described in the embodiment of the present invention; Figure 3 This is a schematic diagram of the eccentric rotor expander described in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Stator; 1.1. Slide groove; 1.2. Cylindrical cavity; 1.3. Spring end cap; 2. Rotor; 3. Shaft; 3.1. Eccentric wheel; 4. Leaves; 5. Needle rollers; 6. Drive bearing; 7. Linear spring. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] The following will refer to Figures 1-3 The invention will be described in detail with reference to the embodiments.

[0028] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a rotating assembly of an eccentric rotor expander, including a rotating shaft 3, a rotor 2 and at least one drive bearing 6.

[0029] The axis of the rotating shaft 3 coincides with the central axis of the entire expander, that is, with the axis of the stator 1. An eccentric wheel 3.1 is provided on the rotating shaft 3. The eccentric wheel 3.1 can be integrally formed with the rotating shaft 3, or it can be a separate design and fixed to the rotating shaft 3 by interference fit or key connection. The specific form is determined based on the processing technology and cost considerations.

[0030] The rotor 2 is a hollow cylindrical structure, eccentrically positioned inside the stator 1. The inner wall of the rotor 2 is fixed to the outer ring of the drive bearing 6 via an interference fit, key connection, or other means. The inner ring of the drive bearing 6 is fixedly fitted onto the eccentric wheel 3.1. This connection method allows the rotor 2 to be suspended on the eccentric wheel 3.1, automatically creating a fixed eccentricity between the geometric center of the rotor 2 and the center of the shaft 3. Under the constraint of the drive bearing 6, the outer cylindrical surface of the rotor 2 will always be tangent to the inner cylindrical surface of the stator 1 at a single point during movement.

[0031] The drive bearing 6 is preferably a high-load-capacity cylindrical roller bearing or a deep groove ball bearing. When multiple drive bearings 6 are provided, they are arranged at axial intervals along the shaft 3 to distribute the load evenly and improve the operational stability of the rotor 2.

[0032] With the precise positioning of the drive bearing 6, the outer wall surface of the rotor 2 remains dynamically tangent to the inner wall surface of the stator 1, meaning that the geometric center of the rotor 2 always has a certain eccentricity relative to the rotation center of the shaft 3. The value of this eccentricity is determined based on the design parameters such as the expander's displacement and expansion ratio.

[0033] When the eccentric rotor expander is working, the gas pressure acting on rotor 2 generates a resultant force on the outer cylindrical surface of rotor 2, and the direction of this resultant force is towards the axis of rotor 2. Due to the eccentricity between rotor 2 and shaft 3, this resultant force generates a torque relative to shaft 3, driving rotor 2 to revolve around shaft 3. The outer ring of drive bearing 6 is fixedly connected to rotor 2, and the inner ring is fixed to eccentric wheel 3.1. Therefore, the revolution of drive bearing 6 around shaft 3 will drive the axis of eccentric wheel 3.1 to revolve around shaft 3, thereby driving shaft 3 to rotate and realize power output. This design structure is extremely simple, greatly reducing the processing and assembly difficulty caused by complex transmission mechanisms, while utilizing the low friction characteristics of bearings to significantly reduce motion loss.

[0034] This invention also provides a cavity structure for an eccentric rotor expander, constructed around the aforementioned rotating assembly. For example... Figure 1 and Figure 2 As shown, the cavity structure includes a stator 1, blades 4, elastic components, and needle rollers 5.

[0035] The stator 1 is a shell with an internal cylindrical working cavity. N radially extending grooves 1.1 and N hollow cylindrical cavities 1.2 are uniformly machined along the circumference, wherein N is 3 to 8, preferably 6. The grooves 1.1 and the cylindrical cavities 1.2 communicate at the end faces of the stator 1. Stator end caps are respectively provided on both sides along the axial direction of the stator 1.

[0036] Blade 4 is slidably disposed within groove 1.1 and can slide radially along groove 1.1. One end of blade 4 contacts the outer wall surface of rotor 2. This end of blade 4 is designed to fit and conform to the smooth outer wall surface of rotor 2 to maintain good contact. Blade 4 is made of high-strength wear-resistant material.

[0037] Since the blades 4 are located in the stator 1, compared with the traditional rotary vane expander, the length of the blades 4 is no longer limited by the size of the rotor 2, which is beneficial to improve the eccentricity and thus increase the power limit of the expander.

[0038] The elastic assembly includes a spring support, a linear spring 7, and a spring end cap 1.3. The spring support is connected to the end of the blade 4 that is not in contact with the rotor 2. One end of the linear spring 7 is fixedly connected to the spring support, and the other end of the linear spring 7 is fixedly connected to the spring end cap 1.3. The spring end cap 1.3 is fixed to the stator 1 by end cap bolts and closes the end of the cylindrical cavity 1.2. The linear spring 7 is located entirely within the hollow cylindrical cavity 1.2 and is always in a compressed state, generating a continuous preload force to ensure that the blade 4 can reliably press against the outer wall of the rotor 2 even at high speeds, preventing the blade 4 from disengaging from the rotor 2 and causing the air cavity seal to fail. However, the mechanical properties of the vortex spring are limited and cannot support the continuous contact between the blade 4 and the rotor 2 under large eccentricity and high speed.

[0039] The linear spring 7 is a standard cylindrical helical compression spring. Its wire diameter, mean diameter and free length are selected from the national standard parts series according to the expander speed, working pressure and other parameters to ensure that its stiffness can provide a radial clamping force sufficient to overcome the inertial force of blade 4 and the pressure difference of the air chamber.

[0040] To guide the blade 4 to move smoothly and reduce friction, a row of needle rollers 5 is embedded in each of the two side walls of the slide groove 1.1. Multiple tiny needles in the needle roller rows 5 protrude from the side walls of the slide groove 1.1, forming rolling contact with the two sides of the blade 4. As the blade 4 reciprocates with the rotation of the rotor 2, the needle roller rows 5 on both sides provide precise guidance and positioning, preventing the blade 4 from tilting or jamming. Simultaneously, they convert sliding friction into rolling friction, further reducing power consumption.

[0041] Since blade 4 is always in contact with rotor 2, two adjacent blades 4, the outer wall section of rotor 2 between two blades 4, the inner wall section of stator 1, and the two stator end covers together form multiple air chambers. For a single air chamber, when high-pressure gas is introduced, the pressure of the high-pressure gas will generate a resultant force on the outer wall surface of rotor 2 surrounding the air chamber. The direction of this resultant force is towards the axis of rotor 2. Since there is a certain eccentricity between the axis of rotor 2 and the axis of shaft 3, this resultant force will generate a torque relative to shaft 3. At the same time, the torque generated by the gas in each air chamber forms a composite torque relative to shaft 3, thereby causing shaft 3 to rotate and realizing power output. As rotor 2 revolves, the volume of each air chamber changes periodically, successively experiencing the processes of intake, expansion, and exhaust, realizing continuous power conversion.

[0042] like Figure 3 As shown, the present invention further provides an eccentric rotor expander, including the aforementioned rotating assembly and cavity structure. In this eccentric rotor expander structure, the drive bearing 6 achieves a low-friction connection between the rotor 2 and the shaft 3, the linear spring 7 reliably clamps the blades 4, and the needle roller array 5 provides stable guidance for the blades 4. The three components work together to enable the expander to operate stably and efficiently under high speed and high pressure.

[0043] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0044] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A rotating assembly of an eccentric rotor expander, characterized in that, include: The rotating shaft coincides with the axis of the stator, and an eccentric wheel is provided on the rotating shaft; The rotor is eccentrically positioned inside the stator. The drive bearing has its inner ring fixed to the eccentric wheel and its outer ring fixedly connected to the inner wall of the rotor. Under the limiting action of the drive bearing, the outer wall of the rotor is tangent to the inner wall of the stator, so that the rotor always maintains a preset eccentricity relative to the shaft.

2. The rotating assembly of the eccentric rotor expander according to claim 1, characterized in that, The drive bearing is a rolling bearing.

3. The rotating assembly of the eccentric rotor expander according to claim 1 or 2, characterized in that, The number of drive bearings is at least one, and they are arranged at axial intervals along the shaft.

4. The rotating assembly of the eccentric rotor expander according to claim 1, characterized in that, The eccentric wheel and the rotating shaft are integrally formed.

5. The rotating assembly of the eccentric rotor expander according to claim 1, characterized in that, The outer ring of the drive bearing is fixed to the inner wall of the rotor with an interference fit, and the inner ring of the drive bearing is fixed to the outer wall of the eccentric wheel with an interference fit.

6. A cavity structure for an eccentric rotor expander, characterized in that, include: The stator has N radially extending grooves evenly distributed along its circumference and N cylindrical cavities corresponding to and connected to each groove, where N is an integer greater than or equal to 3; stator end caps are provided on both sides along the axial direction of the stator. The blades are N in number, each blade is slidably disposed in a corresponding groove, and one end of each blade is in contact with the outer wall surface of the rotor as described in claim 1; The spring assembly includes a linear spring, which is located entirely within a cylindrical cavity and is always in a compressed state. One end of the linear spring is fixed, and the other end abuts against the blade to drive the blade to press against the outer wall of the rotor. Two adjacent blades, rotor, stator, and stator end caps on both sides of the axis form a variable volume air chamber. The resultant force generated by the high-pressure gas acting on the outer wall of the rotor forms a torque relative to the shaft through the eccentricity.

7. The cavity structure of the eccentric rotor expander according to claim 6, characterized in that, It also includes needle roller rows, which are arranged on both sides of the slide groove. The needle rollers of the needle roller rows protrude from the side wall of the slide groove and roll in contact with the side of the blade to guide and limit the blade.

8. The cavity structure of the eccentric rotor expander according to claim 6 or 7, characterized in that, The spring assembly also includes a spring support and a spring end cap. The spring support is fixedly connected to the end of the blade away from the rotor. The spring end cap is fixedly mounted on the stator and closes the end of the cylindrical cavity. One end of the linear spring is connected to the spring support, and the other end of the linear spring is connected to the spring end cap.

9. The cavity structure of the eccentric rotor expander according to claim 8, characterized in that, The linear spring is a cylindrical helical compression spring.

10. An eccentric rotor expander, characterized in that, It includes the rotating assembly according to any one of claims 1 to 5 and the cavity structure according to any one of claims 6 to 9.

Images