A new press fit process for water pump bearing shell

Abstract: This article mainly elaborates on the installation method of rolling bearing shells for petrochemical pumps and oil delivery pumps, demonstrating a new concept of hydraulic assembly.

Keywords: petrochemical pump; Oil pump; Bearing shell; Flexible installation; Hydraulic press fit

 

1. Preface

In recent years, with the large-scale development of the oil and petrochemical industries, the usage of oil and petrochemical pumps has also been increasing. According to the API610 standard, the division of labor for various pumps is more clear: BB1, BB2, BB3, BB4, BB5, OH1, OH2, and NOH3 types, etc.

 

Due to the special application conditions of petrochemical pumps and oil pumps, there are strict requirements for product quality, and the assembly concept of pump equipment is constantly improving. As the core component of pump equipment, the flexible installation of rolling bearing bodies (flexible installation mainly refers to the use of impact free assembly methods such as hot installation, cold installation, and hydraulic pressure installation) is highly valued. The installation method of bearing bodies is of great significance to the assembly quality of the entire pump.

 

2. Problem posing

According to the different structural forms of pumps, the installation forms of rolling bearings and bearing bodies can be divided into two categories: suspension type (such as 0H series) and horizontal rotor type (such as BB1, BB2, BB3, etc.). Based on its structural form, vertical and horizontal press fitting machines have been designed. The vertical press fitting machine is suitable for assembling single-stage suspension pumps, with mature technology and suitable for mass production; The horizontal press fit machine (as shown in Figure 1) is suitable for open type pumps (such as BB1 series oil pumps, etc.), and is a rigid rotor pump with a detachable rotor. However, the disadvantage of this device is that during the pressing process, the bearing bodies at both ends are pressed simultaneously, and the pressure directly acts on the rotor. When the pressure is high, it has a significant impact on the accuracy of the flexible rotor; At the same time, the installation fixture for the pump (BB2) supported by the radial splitting center is cumbersome and inefficient.

 

图片1.png 

Figure 1 Structure of horizontal press fitting machine

 

 

With the development of BB2, BB3 and other series of petrochemical pumps and oil transfer pumps, the continuous improvement of rotor accuracy has made the original pressing method unsuitable for the assembly requirements of new products. Therefore, designing a reasonable portable pressing equipment to further improve productivity is a new issue proposed to process personnel.

 

3. Solution

Based on the structural characteristics of Shandong Shuanglun Fluid Machinery Co., Ltd.'s products, a hollow hydraulic thrust device has been designed, as shown in Figure 1. It mainly consists of a pull rod sleeve, a positioning seat, a pressure cylinder, a piston rod, and a thrust nut. Main working principle: Install the fixture in the position shown in Figure 2, fit the pull rod onto the shaft, connect the press fitting fixture to the bearing body through the positioning plate, adjust the concentricity between the bearing body cavity and the bearing, tighten the thrust nut, and use an electric (or manual) hydraulic pump to pressurize the hydraulic cylinder until the bearing body is installed in place (as shown in Figure 3).

 

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Figure 2 Original installation position of hydraulic thrust device

1. Pull rod sleeve, 2. Positioning seat, 3. Pressure cylinder, 4. Piston rod, 5. Thrust nut

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Figure 3 Position of hydraulic thrust device after bearing body is in place

 

 

This method only involves the relative motion between the threaded part of the shaft end and the bearing body (as shown in Figures 2 and 3), and the generated tension will not affect the rotor, ensuring the accuracy requirements of the rotor and suitable for the assembly requirements of all similar products.

 

This tool can be used for pressing different specifications of bearing bodies after replacing several simple parts such as rod sleeves, positioning seats, and thrust nuts. The tooling production is simple and easy to standardize operations.

 

4. Application effect

1) This set of press fit tools reasonably utilizes the principle of force transmission to ensure rotor accuracy.

2) Improved labor efficiency and reduced labor intensity.

3) Simple to make, lightweight, and easy to carry, it is an ideal assembly and maintenance tool.

 

2024 October 4th Week VAFEM Product Recommendation:

Wheel Hub Bearings:

VAFEM Hub units are designed to allow rear wheels, especially in passenger cars, to turn on an axle even under heavy loads.

Features:

magnetic, electric, and mechanic ABS

with and without ABS

flange only

Steel Material: GCr15/52100/100Cr6

Steel Type: Forged

Ball Grade: G10

Grease: Shell

图片4.png 

 


2024-10-30

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