WO2018072515A1

WO2018072515A1 - Impeller locking structure and compressor

Info

Publication number: WO2018072515A1
Application number: PCT/CN2017/094669
Authority: WO
Inventors: 钟瑞兴; 雷连冬; 张治平; 刘建飞; 蒋楠; 蒋彩云; 陈玉辉; 周义; 刘增岳
Original assignee: 珠海格力电器股份有限公司
Priority date: 2016-10-21
Filing date: 2017-07-27
Publication date: 2018-04-26
Also published as: CN106402019A

Abstract

Disclosed is an impeller locking structure, comprising an impeller (1), a main shaft (2), and keys (3). An inner wall of a shaft hole of the impeller (1) is provided with an impeller keyway (4), and an outer surface of the main shaft (2) is provided with a main shaft keyway (5) corresponding to the impeller keyway (4). The keys (3) are accommodated between the impeller keyway (4) and the main shaft keyway (5) to achieve a circumferential fixation of the impeller (1) and the main shaft (2). The radial cross sections of the impeller keyway (4) and the main shaft keyway (5) are all smooth curves. Further disclosed is a compressor having the impeller locking structure. The impeller locking structure solves the problem of stress concentration in keying fit, increases the strength of the impeller and reduces the degree of weakening the main shaft. With the same strength limit, using the impeller locking structure enables more keyways and keys to be provided to improve the uniformity of load distribution and the capability of transferring the moment from the main shaft, in turn improving the refrigeration capacity of the compressor.

Description

Impeller locking structure and compressor

Technical field

The invention relates to the technical field of compressors, in particular to an impeller locking structure and a compressor.

Background technique

The impeller of the centrifugal compressor works on the gas to increase the gas energy, and the energy increased by the gas is positively correlated with the rotational speed of the impeller. Depending on the pressure ratio, the impeller speed can reach several thousand revolutions per minute. For example, when the pressure ratio is high, it is even more than 25,000 rpm. Therefore, in order to ensure the reliability and safety of the impeller, the impeller locking structure plays an important role.

There are two types of impeller locking methods commonly used in centrifugal compressors in the prior art: one is a thermal sleeve with locking and the other is a keying locking.

Wherein, when the hot sleeve is matched with the lock, the impeller is heated to about 100 ° C, and after being heated and expanded, it is quickly assembled with the main shaft, so that the assembly interference amount generated by the impeller cooling can be used for the purpose of locking. Although the hot sleeve and the locking structure are simple, no additional parts need to be added, but heating equipment is required, which is not suitable for disassembly, and has strict requirements on the assembly process.

In the prior art, when the key is locked, it is necessary to rely on the cooperation of the keyway and the key to restrain the displacement of the impeller and transmit the torque. However, since the key used is a standard member, its inherent right-angled structure causes a large concentration of stress at the end of the keyway, reducing the strength of the impeller.

Summary of the invention

The invention provides an impeller locking structure and a compressor, so as to solve the problem that the stress concentration of the key matching in the prior art is large and the impeller strength is low.

In order to solve the above problems, as an aspect of the present invention, an impeller locking structure is provided, including an impeller, a main shaft and a key, and an inner surface of the shaft hole of the impeller is provided with an impeller key groove, and an outer surface of the main shaft is opened. There is a spindle keyway corresponding to the impeller keyway, and the key is mounted on the impeller key Between the slot and the main shaft keyway, the circumferential direction of the impeller and the main shaft is fixed, and the radial cross section of the impeller keyway and the main shaft keyway are smooth curves.

Preferably, the main shaft includes a first end and a second end, and the main shaft key groove is located between the first end and the second end.

Preferably, the first end of the main shaft is formed with a thread, and the second end of the main shaft is formed with a shoulder.

Preferably, the impeller locking structure further includes a lock nut mounted at the first end, the impeller being axially locked between the shoulder and the lock nut.

Preferably, the nominal diameter M of the lock nut and the diameter D of the shoulder meet: 1.3 M ≤ D ≤ 1.8 M.

Preferably, the surface roughness of the surface of the lock nut and/or the shoulder that is in contact with the impeller is less than or equal to 3.2 μm.

Preferably, the surface of the lock nut and/or the shoulder contacting the impeller has a perpendicularity to the centerline of the main shaft of less than or equal to 0.05 mm.

Preferably, the axial length L1 of the lock nut, the axial length L2 of the impeller keyway, and the axial length L3 of the main shaft keyway satisfy: L1>2 (L3-L2).

Preferably, the key is spherical, and the radius R1 of the spherical shape and the nominal diameter M of the lock nut satisfy the following relationship: 0.2M≤R1≤0.4M.

Preferably, the key is spherical, and the number n of the keys, the axial length L2 of the main shaft key groove, and the cross-sectional radius R1 of the key satisfy: n < (L2 / (2R1)).

Preferably, the key is in an interference fit with the spindle keyway.

Preferably, the key is in point contact with the impeller keyway.

Preferably, the key is spherical, and the depth t of the main shaft keyway, the cross-sectional radius R1 of the key, and the cross-sectional radius R2 of the main shaft keyway satisfy: t=R1=R2.

Preferably, the key is spherical, and the axial length L3 of the main shaft key groove, the axial length L2 of the impeller key groove, and the cross-sectional radius R1 of the key satisfy: L3 ≥ (L2+2R1).

Preferably, the axial length L3 of the main shaft keyway, the axial length L2 of the impeller key groove, and the cross-sectional radius R1 of the key satisfy: (L2+2R1)≤L3≤1.2 (L2+2R1).

Preferably, the main shaft key groove is a spherical groove, and an inner surface of the spherical groove is formed by a spherical body in a direction in which the main shaft key groove extends from one end of the main shaft key groove to the other end. Composition.

Preferably, a plurality of the main shaft key grooves are formed on the main shaft, and the plurality of main shaft key grooves are evenly distributed along a circumferential direction of the main shaft.

Preferably, the number of the spindle keyways is an even number.

Preferably, the number of the spindle keyways is 2 to 4.

Preferably, a first space is formed between the impeller keyway and the main shaft keyway, and the first space is circularly projected along an axial direction of the radial section of the impeller.

Preferably, the center of the circle is located on one side of the impeller keyway.

Preferably, the bond is spherical, or cylindrical, or an elliptical cylinder.

Preferably, the impeller locking structure comprises a plurality of spherical keys, the diameter error between each of the keys being less than or equal to 50 [mu]m.

The present invention also provides a compressor comprising the above described impeller locking structure.

Since the impeller keyway and the main shaft keyway of the invention adopt a rounded structure design, the conventional key and keyway fixing structure in the prior art is broken, the stress concentration problem of the keying is effectively solved, and the impeller strength is improved. The keyway of the invention reduces the degree of weakening of the main shaft. Under the same strength limit, the invention can provide more keyways and keys, thereby improving the uniformity of load distribution and the ability to transmit the spindle torque, thereby improving the refrigeration capacity of the compressor. . The structure of the invention is simple, safe and reliable, and has good processability and is easy to popularize.

DRAWINGS

Figure 1 is a schematic exploded view of the impeller locking structure of the present invention;

Figure 2 is a schematic cross-sectional view showing the impeller locking structure of the present invention;

Fig. 3 is a schematic cross-sectional view taken along line A-A of Fig. 2.

Reference numerals in the figure: 1, impeller; 2, spindle; 3, key; 4, impeller keyway; 5, spindle keyway; 6, shoulder; 7, lock nut.

detailed description

The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Referring to FIGS. 1 to 3, the impeller locking structure of the present invention includes an impeller 1, a main shaft 2, and one or more (two or more) keys 3 for transmitting power. The impeller locking structure is particularly suitable for use in centrifugal compressors and the like.

Wherein, the middle portion of the impeller 1 has a shaft hole, and one or more impeller key grooves 4 are formed on the inner wall of the shaft hole. Further, on the outer surface of the main shaft 2, one or a plurality of main shaft key grooves 5 provided corresponding to the impeller key grooves 4 are opened. Thus, when the main shaft 2 is mounted in the shaft hole of the impeller 1, the key 3 is accommodated between the impeller keyway 4 and the main shaft keyway 5, so that the circumferential direction of the impeller 1 and the main shaft 2 is fixed, thereby transmitting motion and torque. And pass the power. Different from the prior art, the radial cross section of the impeller keyway 4 and the main shaft keyway 5 in the present invention is also an axial projection along the radial section of the impeller 1 or the main shaft 2, and both are smooth curves. For example, a first space is formed between the impeller keyway 4 and the main shaft keyway 5, and the first space is surrounded by a curved surface having a rounded transition shape such as a circular shape along the axial direction of the radial section of the impeller 1.

As shown in FIGS. 1 and 2, the main shaft 2 of the present invention includes a first end and a second end, and the above-described main shaft key groove 5 is provided at a position between the first end and the second end. As shown, the main shaft keyway 5 occupies only a portion of the length of the middle portion of the main shaft 2.

For the purpose of installation, the present invention provides an external thread on the first end of the main shaft 2, and a shoulder 6 is formed at a portion of the second end of the main shaft 2 so that the main shaft 2 is formed as a stepped shaft. During installation, the first end of the main shaft 2 is passed through the shaft hole of the impeller 1, so that the right side of the impeller 1 rests on the shoulder 6, and then a lock nut 7 is mounted on the first end of the main shaft 2. In this way, the impeller 1 can be axially locked and fixed to the main shaft 2. Preferably, the inner diameter of the lock nut 7 is provided with a common metric internal thread and is connected to the main shaft 2 by a thread, thereby achieving axial fixation of the impeller 1 . Preferably, the nominal diameter M of the lock nut 7 and the diameter D of the shoulder 6 satisfy: 1.3 M ≤ D ≤ 1.8 M.

In order to ensure the assembly perpendicularity after the impeller is locked, preferably, the surface roughness of the surface of the lock nut 7 and/or the shoulder 6 that is in contact with the impeller 1 is less than or equal to 3.2 μm, or more preferably, the lock nut 7 And/or the surface of the shoulder 6 that is in contact with the impeller 1 has a perpendicularity to the centerline of the main shaft 2 of less than or equal to 0.05 mm.

In order to ensure the effective length of the threaded connection, the axial length L1 of the lock nut 7, the axial length L2 of the impeller keyway 4, and the axial length L3 of the main shaft keyway 5 preferably satisfy: L1>2 (L3-L2).

Preferably, the key 3 is spherical, and in view of the relationship between the strength of the main shaft and the object to be locked, the present invention preferably satisfies the following relationship between the radius R1 of the spherical shape and the nominal diameter M of the lock nut 7: 0.2 M ≤ R1 ≤0.4M. The use of the spherical key 3 is easy to realize mass production because of its conventional structure and simplicity.

When the axial length L2 of the main shaft key groove 5 is large and the number of the keys 3 is larger, the transmission torque of the key 3 is smoother. In view of the locking action of the lock nut 7 on the impeller 1, preferably, the number n of the lock nut 7, the axial length L2 of the main shaft keyway 5, and the cross-sectional radius R1 of the key 3 satisfy: n < (L2/ (2R1)).

Preferably, the key 3 and the spindle keyway 5 are in an interference fit, and the interference can be determined according to the design requirements of the manual. The contact pair between the key 3 and the impeller keyway 4 is in point contact. In operation, in order to level the reaction force of the impeller against the key 3 and pass the center of the key 3, preferably, the depth t of the main shaft keyway 5, the cross-sectional radius R1 of the key 3, and the cross-sectional radius R2 of the main shaft keyway 5 satisfy: t =R1=R2.

In order to achieve free assembly of the key 3 and the impeller 1 (i.e., the key 3, the impeller 1 has no sequential assembly order), preferably the axial length L3 of the main shaft keyway 5, the axial length L2 of the impeller keyway 4, and the cross section of the key 3 The radius R1 satisfies: L3 ≥ (L2+2R1). In combination with the above-mentioned operative effective connection length of the lock nut 7 and the main shaft 2, generally, the axial length L3 of the main shaft keyway 5, the axial length L2 of the impeller keyway 4, and the cross-sectional radius R1 of the key 3 satisfy: (L2) +2R1) ≤ L3 ≤ 1.2 (L2+2R1).

In order to reduce the machining stress of the spindle keyway 5 and reduce the weakening effect on the spindle 2, the spindle keyway 5 adopts a "spherical groove". More specifically, the inner surface of the spherical groove is constituted by a contour surface formed by a ball which is rolled in the extending direction of the main shaft key groove 5 from one end of the main shaft key groove 5 to the other end. As shown in Fig. 2, the left and right ends of the spindle keyway 5 are spherical shapes just wrapped around the key 3. In addition, as the depth t of the main shaft keyway 5 is different, the cross-sectional shape should be an arc shape of different arc lengths.

In order to improve the stress environment of the main shaft 2 and the key 3, it is preferable that the number of the main shaft key grooves 5 is an even number.

Preferably, the main shaft 2 is formed with a plurality of main shaft key grooves 5, and the plurality of main shaft key grooves 5 are evenly distributed along the circumferential direction of the main shaft 2. In view of the effect of the keyway on the shaft strength weakening, preferably, the number of the main shaft key grooves 5 is 2 to 4. Preferably, the center of the circle is located on one side of the impeller keyway 4.

The key 3 in the present invention should adopt a round structure of balls, so that the processing stress can be reduced on the one hand, and on the other hand, when the main shaft and the impeller are assembled, the key 3 serves as a connection medium for the two, and can be slidably assembled into a rolling assembly. To reduce friction and improve the assembly process. In addition to the spherical shape, the key 3 can be processed into a cylindrical shape, an elliptical cylindrical shape, or the shape of other rounded structures.

Preferably, the impeller locking structure includes a plurality of keys 3, and the shape (diameter) error between the keys 3 is less than or equal to 5 wires (50 μm) in order to ensure the reliability of the transmitted torque and the uniformity of the transmitted load.

Through the above-mentioned impeller locking structure, not only can the impeller be effectively locked, the working environment of the impeller is optimized, but also the impeller can be assembled and disassembled, and the assembly efficiency and the after-sale operability are improved.

Because the above technical solution is adopted, the invention can solve the problem that the assembly of the impeller and the main shaft is difficult and difficult to disassemble after assembly when the hot sleeve is matched with the locking impeller; the key groove and the key stress concentration problem when the key is matched with the locking impeller. Compared with the thermal sleeve locking, the invention simplifies the impeller assembly process and equipment and improves The assembly efficiency and the disassembly are convenient; compared with the thermal sleeve locking, the flexible impeller locking structure of the invention can not only effectively lock the impeller, optimize the working environment of the impeller, but also facilitate assembly and disassembly of the impeller, and improve assembly efficiency and After-sales operability.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

An impeller locking structure comprises an impeller (1), a main shaft (2) and a key (3), and an inner surface of the shaft hole of the impeller (1) is provided with an impeller keyway (4), and the main shaft (2) a spindle keyway (5) corresponding to the impeller keyway (4) is disposed on the outer surface, and the key (3) is received between the impeller keyway (4) and the spindle keyway (5). The circumferential fixing of the impeller (1) and the main shaft (2) is realized, characterized in that the radial cross section of the impeller keyway (4) and the main shaft keyway (5) are both smooth curves.
The impeller locking structure according to claim 1, wherein said main shaft (2) comprises a first end and a second end, said main shaft keyway (5) being located at said first end and said second end between.
The impeller locking structure according to claim 2, characterized in that the first end of the main shaft (2) is formed with a thread, and the second end of the main shaft (2) is formed with a shoulder (6).
The impeller locking structure according to claim 3, wherein the impeller locking structure further comprises a lock nut (7) mounted at the first end, the impeller (1) being axially locked Between the shoulder (6) and the lock nut (7).
The impeller locking structure according to claim 4, characterized in that the nominal diameter M of the lock nut (7) and the diameter D of the shoulder (6) satisfy: 1.3 M ≤ D ≤ 1.8 M .
The impeller locking structure according to claim 4, characterized in that the surface roughness of the surface of the lock nut (7) and/or the shoulder (6) in contact with the impeller (1) is smaller than Or equal to 3.2μm.
The impeller locking structure according to claim 4, characterized in that the surface of the lock nut (7) and/or the shoulder (6) that is in contact with the impeller (1) faces the main shaft ( 2) The centerline has a perpendicularity of less than or equal to 0.05 mm.
The impeller locking structure according to claim 4, characterized in that the axial length L1 of the lock nut (7), the axial length L2 of the impeller keyway (4), and the spindle keyway (5) The axial length L3 satisfies: L1>2 (L3-L2).
The impeller locking structure according to claim 4, wherein the key (3) is spherical.