WO2021088321A1

WO2021088321A1 - Three-cylinder three-support crankshaft for diaphragm pump, and processing process

Info

Publication number: WO2021088321A1
Application number: PCT/CN2020/086303
Authority: WO
Inventors: 李峰; 王建成; 蒋科; 祁文; 刘乐; 王贵; 屈卫德; 左仓; 卢飚; 段鹏飞; 宁轩; 赵军; 金忠升; 付岳峰
Original assignee: 陕西航天动力高科技股份有限公司
Priority date: 2019-11-08
Filing date: 2020-04-23
Publication date: 2021-05-14
Also published as: CN110792684B; CN110792684A

Abstract

A three-cylinder three-support crankshaft for a diaphragm pump, and a processing process. The crankshaft comprises an input shaft (8), multiple journals, and multiple crank arms (7) for connecting the journals. The multiple journals comprise the following components arranged in sequence: a first support journal (1), a first connecting rod journal (4), a second connecting rod journal (5), a second support journal (2), a third connecting rod journal (6), and a third support journal (3). The third support journal (3) and the input shaft (8) are coaxially connected. The first support journal (1), the second support journal (2), and the third support journal (3) are coaxially disposed. The first connecting rod journal (4), the second connecting rod journal (5), and the third connecting rod journal (6) have the same diameter, and are uniformly distributed in a circumferential direction of a circle having the axis of the first support journal (1) as the center thereof. Each of the crank arms (7) consists of an arc-shaped transition structure having a varying diameter, and having an elliptical shape when viewed in a cross-section perpendicular to the line connecting the centers of circles on two side end surfaces of the crank arm (7).

Description

Three-cylinder three-support crankshaft for diaphragm pump and processing technology

Technical field

The invention relates to a crankshaft technology in a reciprocating pump, in particular to a three-cylinder three-support crankshaft for a diaphragm pump and a processing technology.

Background technique

In a reciprocating pump, the crankshaft converts the rotating motion of the reducer into the circular motion of the crank pin (a component of the crankshaft). The circular motion of the crank pin is then converted into one of the important components of the reciprocating motion of the piston. Periodic alternating load produces alternating torsional stress and variable bending stress, so it is also the most important force-bearing component in the crank connecting rod mechanism.

Commonly used crankshafts in reciprocating pumps can be divided into crankshafts, crankshafts, eccentric shafts, and "N"-shaped shafts. Among them, the crankshaft is the most commonly used. The most common crankshafts currently on the market are three-turn double-support and three-turn four-support; among them, the three-turn double support includes two coaxially arranged support journals and two supports. There are crank arms between the three connecting rod journals between the journals, between the adjacent two connecting rod journals, and between the connecting rod journal and the supporting journal. Since the three connecting rod journals are connected as a whole, This makes the rigidity and strength of the three-turn double support poor, and the structure is bulky; the three-turn four-support is based on the three-turn double support, adding two supports, and the crank arm between two adjacent connecting rod journals serves as the intermediate support. The support increases, the crankshaft bending deformation and the main journal inclination, the stiffness and strength are better, but for the reciprocating pump with a large stroke, the diameter of the crank arm is larger. As shown in Figure 1, the crank arm 01 structure is a cylinder, resulting in the weight of the crankshaft. Too heavy, the mechanical properties cannot be guaranteed, the pump cannot work normally, and for a crankshaft with a larger rotating diameter, this design will make the crank arm larger, which will lead to expensive prices and difficult processing and assembly processes.

Summary of the invention

In order to solve the technical problems of poor rigidity and strength of the existing crankshaft, heavy structure, heavy weight, high price, and difficult processing and assembly processes, the present invention provides a three-cylinder three-support crankshaft for a diaphragm pump and a processing technology.

In order to achieve the above objectives, the technical solution provided by the present invention is:

A three-cylinder three-support crankshaft for a diaphragm pump is special in that it includes an input shaft, a plurality of journals, and a plurality of crank arms for adapting and connecting adjacent journals; The first supporting journal, the first connecting rod journal, the second connecting rod journal, the second supporting journal, the third connecting rod journal, the third supporting journal; the first supporting journal, the second The supporting journal and the third supporting journal are coaxially arranged, and the third supporting journal is coaxially connected with the input shaft; the diameters of the first connecting rod journal, the second connecting rod journal, and the third connecting rod journal are equal The diameters of the first support journal and the third support journal are equal, and smaller than the diameter of the second support journal and the first connecting rod journal; the first connecting rod journal, the second connecting rod journal , The third connecting rod journal is uniformly distributed along the clockwise circumference with the axis of the first supporting journal as the center; all crank arms are of circular arc reducing transition structure, and the vertical section connecting the center of the ends of the crank arms is Oval.

Further, the aspect ratio of the ellipse is in the range of 1.0 to 1.8.

Further, the aspect ratio of the ellipse is in the range of 1.0 to 1.6.

Further, the diameter ratio of the first support journal and the second support journal is 0.3 to 0.8; the diameter ratio of the first support journal and the first connecting rod journal is 0.5 to 1.0.

Further, the diameter ratio of the first support journal and the second support journal is 0.53; the diameter ratio of the first support journal and the first connecting rod journal is 0.83.

Further, the radial size of the port of the second supporting journal is larger than the radial size of the ports of the second connecting rod journal and the third connecting rod journal on both sides thereof;

The radial size of the port of the crank arm between the second connecting rod journal and the second support journal gradually increases from an end close to the second connecting rod journal to an end close to the second support journal;

The radial size of the port of the crank arm between the second support journal and the third connecting rod journal gradually decreases from an end close to the second support journal to an end close to the third connecting rod journal.

Further, the crank arm between the second connecting rod journal and the second support journal and an end close to the second connecting rod journal is provided with a weight reduction structure;

The weight reduction structure is located on the outer side of the second connecting rod journal.

Further, the raw material of the crankshaft is alloy steel.

Further, the crankshaft raw material is 34CrNiMo or 35CrMo or 42CrMo or 40Cr.

At the same time, the present invention provides a machining process for a three-cylinder three-support crankshaft for a diaphragm pump, which is special in that it includes the following steps:

1) According to the design size of the crankshaft, it is processed into a blank by the integral forging process;

2) Rough turning on the journal part of the blank;

3) Precision milling is used for the input shaft and journal, and precision grinding is used for the crank arm.

Compared with the prior art, the advantages of the present invention are:

1. The three-cylinder and three-support crankshaft for the diaphragm pump of the present invention has a three-turn three-support structure, wherein the three-turn includes a first connecting rod journal, a second connecting rod journal, and a third connecting rod journal, and the three supports include the first support The journal, the second support journal, and the third support journal. Compared with the two supports, the present invention adds one support, so the strength is more in line with the requirements. Compared with the four supports, the present invention has one less force. The point and the force is more uniform, and the processing and assembly difficulty are reduced.

2. The crank arm between the three-cylinder and three-supported crankshaft journals of the diaphragm pump of the present invention is a circular arc reducing transition structure, and the radial dimension of the crank arm is small. When the bearing is installed on the crankshaft journal, the strength and rigidity can be ensured. Under the premise of ensuring the smooth passage of the bearing through the crank arm, the overall weight of the crankshaft is lighter, the cost is low, and the processing and assembly process is simple.

3. The three-cylinder three-support crankshaft for the diaphragm pump of the present invention is provided with a weight reduction structure on the crank arm between the second connecting rod journal and the second support journal, which can effectively reduce the weight and has little effect on the strength.

4. The three-cylinder and three-support crankshaft for the diaphragm pump of the present invention adopts an integral forging process to make a blank, which can improve the rigidity and strength of the crankshaft and prevent stress damage.

Description of the drawings

Figure 1 is a partial structural diagram of an existing crankshaft;

In Figure 1, the reference signs are as follows:

01-Crank arm.

2 is a schematic diagram of the structure of the three-cylinder and three-support crankshaft for the diaphragm pump of the present invention;

Figure 3 is a left side view of Figure 2;

Figure 4 is a partial cross-sectional view of Figure 2 (the first connecting rod journal, the second connecting rod journal and the crank arm between the two in the three-cylinder three-support crankshaft for a diaphragm pump);

Figure 5 is a cross-sectional view taken along the line A-A of Figure 4;

Fig. 6 is a three-dimensional structure diagram of a three-cylinder three-support crankshaft for the diaphragm pump of the present invention;

In Figures 2 to 6, the reference signs are as follows:

1-first support journal, 2-second support journal, 3-third support journal, 4-first connecting rod journal, 5-second connecting rod journal, 6-third connecting rod journal , 7-crank arm, 8-input shaft, 9-weight reduction structure.

Detailed ways

The present invention will be further described in detail below in conjunction with the drawings and embodiments.

As shown in Figures 2 and 6, a three-cylinder three-support crankshaft for a diaphragm pump includes an input shaft 8, multiple journals, and multiple crank arms 7 for adapting and connecting adjacent journals. It includes a first supporting journal 1, a first connecting rod journal 4, a second connecting rod journal 5, a second supporting journal 2, a third connecting rod journal 6, and a third supporting journal 3 arranged in sequence; A supporting journal 1, a second supporting journal 2, and a third supporting journal 3 are arranged coaxially, and the third supporting journal 3 is coaxially connected with the input shaft 8; the first connecting rod journal 4, the second connecting rod shaft The diameters of the neck 5 and the third connecting rod journal 6 are equal; the diameters of the first supporting journal 1 and the third supporting journal 3 are equal and smaller than the diameters of the second supporting journal 2 and the first connecting rod journal 4; As shown in Figure 3, the first connecting rod journal 4, the second connecting rod journal 5, and the third connecting rod journal 6 are evenly distributed along a clockwise circle with the axis of the first supporting journal 1 as the center; all cranks The arms 7 are of a circular arc reducing transition structure, and the vertical cross section at the midpoint of the line connecting the centers of the ends of the two sides of the crank arm 7 is an ellipse. The aspect ratio of the ellipse is in the range of 1.0 to 1.8, and the aspect ratio of the ellipse is preferably in the range of 1.0 to 1.6.

The radial dimension of the port of the second supporting journal 2 is larger than the radial dimension of the ports of the second connecting rod journal 5 and the third connecting rod journal 6 on both sides; the second connecting rod journal 5 and the second supporting journal The radial size of the port of the crank arm 7 between 2 gradually increases from the end close to the second connecting rod journal 5 to the end close to the second supporting journal 2; between the second supporting journal 2 and the third connecting rod journal 6 The radial dimension of the port of the crank arm 7 gradually decreases from the end close to the second supporting journal 2 to the end close to the third connecting rod journal 6, preferably between the second connecting rod journal 5 and the second supporting journal 2. 7 And the end close to the second connecting rod journal 5 is provided with a weight reduction structure 9, which is located on the outside of the second connecting rod journal 5, as shown in Figure 6, which can effectively reduce weight without affecting the strength Big.

In this embodiment, the diameter of the second support journal 2 and the diameter of the first connecting rod journal 4 are both larger than the diameter of the first support journal 1. Generally, the diameters of the first support journal 1 and the second support journal 2 The ratio is 0.3 to 0.8, the diameter ratio of the first support journal 1 and the first connecting rod journal 4 is 0.5 to 1.0, and the preferred size is that the diameter ratio of the first support journal 1 and the second support journal 2 is 0.53, The diameter ratio of the first support journal 1 and the first connecting rod journal 4 is 0.83.

Example

A three-cylinder three-support crankshaft for a diaphragm pump. The first support journal 1, the first connecting rod journal 4, the second connecting rod journal 5, the second support journal 2, the third connecting rod journal 6, and the The diameters of the three supporting journals 3 and the input shaft 8 are respectively 300mm, 360mm, 360mm, 560mm, 360mm, 300mm, 230mm; since the first connecting rod journal 4 and the second connecting rod journal 5 are of equal diameter, the distance is relatively long , It is likely that stress concentration will occur, fatigue strength will be insufficient, and fracture will occur. Therefore, the crank arm between the first connecting rod journal 4 and the second connecting rod journal 5 should be reasonably designed to improve the stiffness and fatigue of the crank arm. strength.

The distance between the axes of the first connecting rod journal 4 and the second connecting rod journal 5 is 346mm, and the distance between the adjacent end faces of the first connecting rod journal 4 and the second connecting rod journal 5 is 355mm, namely The distance between the right end surface of the first connecting rod journal 4 and the left end surface of the second connecting rod journal 5 in Fig. 4 is 355mm, the right end of the first connecting rod journal 4 and the second connecting rod journal 5 The vertical section at the midpoint of the center line of the left end is an ellipse, as shown in Figure 5. The long side of the ellipse is 354mm and the short side is 290mm. At this time, the aspect ratio of the ellipse is 1.22. The distance between each connecting rod journal and the center line of the supporting journal is the crankshaft gyration radius, which is 200mm, and the distance between the end faces of adjacent connecting rod journals is related to the cylinder spacing.

The crankshaft converts the rotational movement of the reducer into the reciprocating movement of the crosshead and the plunger. In this embodiment, the first support journal 1 and the third support journal 3 of the crankshaft are arranged on the box of the crankcase, and the input shaft 8 is located in the box. The body is connected to the reducer. The three connecting rod journals are connected to the big end of the connecting rod through bearings. The small end of the connecting rod is connected to one end of the cross head through a cross head pin through a cross head pin, and the other end of the cross head is connected to the big end of the connecting rod through a cross head pin. The plunger outside the box is connected; the reducer drives the crankshaft to rotate, the connecting rod journal of the crankshaft drives the crosshead to make a reciprocating linear motion through the connecting rod, and the crosshead drives the plunger to make a reciprocating linear motion. An oil sump is set at the bottom of the crankcase body, and the connecting rod journal is connected with a bearing, which adopts splash lubrication. Through the rotation of the crankshaft, the bearing is in contact with the lubricating fluid in the box when it rotates, and the bearing is lubricated. The neck is lubricated and the lubrication effect is good. If the crank arm is too thin, it will affect the mechanical properties of the crankshaft, and it is prone to fatigue damage, cracks, or even breakage; if it is too thick, the bearing will not pass. Therefore, the crank arms of the first connecting rod journal 4 and the second connecting rod journal 5 are designed as a circular arc reducing transition structure, and the length-to-width ratio of the vertical cross-section ellipse at the midpoint of the line connecting the centers of the two ends is 1.22, The bearing is installed on the connecting rod journal through the bearing to the greatest extent to ensure the tensile strength, yield and fatigue strength of the crankshaft.

A machining process for a three-cylinder and three-support crankshaft for a diaphragm pump includes the following steps:

2) Rough turning of the journal part of the blank;

3) The input shaft 8 and journal are processed by precision milling, and the crank arm 7 is processed by precision grinding.

Among them, the crankshaft processing raw material is alloy steel, 34CrNiMo can be selected, quenched and tempered HB275-305, tensile strength: ≥910MPa, yield strength: ≥700MPa, elongation: (%c50mm) 14%, reduction of area: ≥35%, Impact power: ≥25%; the crankshaft is processed by forgings, the overall strength is obviously improved, the service life is increased, the machining accuracy will also be improved, the overall performance is better, the crank arm and the support journal are smoother; in addition, the crankshaft processing raw material can also be 35CrMo Or 42CrMo or 40Cr.

The above is only a description of the preferred embodiments of the present invention, and does not limit the technical solutions of the present invention to this. Any known modification made by those skilled in the art on the basis of the main technical concept of the present invention belongs to the protection of the present invention. Technical category.

Claims

A three-cylinder three-support crankshaft for a diaphragm pump is characterized in that it comprises an input shaft (8), a plurality of journals, and a plurality of crank arms (7) for adapting and connecting adjacent journals;

The multiple journals include a first supporting journal (1), a first connecting rod journal (4), a second connecting rod journal (5), a second supporting journal (2), and a third supporting journal (1), a first connecting rod journal (4), a second supporting journal (2), and a third Connecting rod journal (6), third supporting journal (3);

The first support journal (1), the second support journal (2) and the third support journal (3) are coaxially arranged, and the third support journal (3) is coaxially connected with the input shaft (8);

The diameters of the first connecting rod journal (4), the second connecting rod journal (5), and the third connecting rod journal (6) are equal;

The diameters of the first support journal (1) and the third support journal (3) are equal and smaller than the diameters of the second support journal (2) and the first connecting rod journal (4);

The first connecting rod journal (4), the second connecting rod journal (5), and the third connecting rod journal (6) take the shaft center of the first support journal (1) as the center and are evenly distributed along the clockwise circumference. cloth;

All crank arms (7) have a circular arc reducing transition structure, and the vertical cross section connecting the centers of the end faces on both sides of the crank arm (7) is elliptical.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 1, wherein the aspect ratio of the ellipse is in the range of 1.0 to 1.8.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 2, wherein the aspect ratio of the ellipse is in the range of 1.0 to 1.6.
The three-cylinder three-support crankshaft for a diaphragm pump according to any one of claims 1 to 3, characterized in that: the diameter ratio of the first support journal (1) and the second support journal (2) is 0.3-0.8;

The diameter ratio of the first supporting journal (1) and the first connecting rod journal (4) is 0.5-1.0.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 4, characterized in that: the diameter ratio of the first support journal (1) and the second support journal (2) is 0.53;

The diameter ratio of the first supporting journal (1) and the first connecting rod journal (4) is 0.83.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 1, wherein the radial size of the port of the second support journal (2) is larger than that of the second connecting rod journals (5) and the second connecting rod journals (5) on both sides thereof. The radial size of the port of the three-link journal (6);

The radial dimension of the port of the crank arm (7) between the second connecting rod journal (5) and the second supporting journal (2) is from the end close to the second connecting rod journal (5) to the second supporting shaft The neck (2) gradually increases at one end;

The radial dimension of the port of the crank arm (7) between the second supporting journal (2) and the third connecting rod journal (6) is from the end close to the second supporting journal (2) to the third connecting rod shaft The neck (6) gradually decreases at one end.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 6, characterized in that: the crank arm (7) between the second connecting rod journal (5) and the second support journal (2) is close to the second A weight reduction structure (9) is opened at one end of the connecting rod journal (5);

The weight reduction structure (9) is located outside the second connecting rod journal (5).
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 7, wherein the material of the crankshaft (11) is alloy steel.
The three-cylinder three-support crankshaft for a diaphragm pump according to claim 8, wherein the material of the crankshaft (11) is 34CrNiMo or 35CrMo or 42CrMo or 40Cr.
The machining process of a three-cylinder three-support crankshaft for a diaphragm pump according to any one of claims 1 to 9, characterized in that it comprises the following steps:

1) According to the design size of the crankshaft, it is processed into a blank by the integral forging process;

2) Rough turning on the journal part of the blank;

3) The input shaft (8) and the journal are processed by precision milling, and the crank arm (7) is processed by precision grinding.