Gear pump bearing bush interference assembly device and method
By using devices such as sleeve pressing fixtures and lever indicators, combined with mechanized operations, the problems of difficult positioning and potential safety hazards in the traditional gear pump housing assembly bushing assembly process are solved, and efficient and safe bushing interference assembly is achieved.
Patent Information
- Application Number
- CN202510921880.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-09-19
AI Technical Summary
The traditional gear pump housing assembly bearing bushing interference fit assembly process lacks a positioning reference, resulting in the bushing and housing being out of alignment and verticality being difficult to ensure. Heat conduction also causes the bushing to get stuck, making the operation cumbersome and time-consuming, and posing a safety risk.
An assembly device consisting of a sleeve pressing fixture, a lever gauge, a fixture base, and a verticality guide rail is used. Combined with the lever gauge reading and a press, the coaxiality and verticality of the bushing are ensured. Mechanized operation replaces manual tapping, and a fixture is used for precise guiding and fixing.
It improves assembly efficiency, ensures the coaxiality and verticality of the bushing and the housing, simplifies the operation process, reduces safety risks, and improves production efficiency and quality.
Smart Images
Figure CN120663095A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of mechanical structures, relates to bushing interference assembly, and in particular to a gear pump bearing bushing interference assembly device and method. Background Art
[0002] An oil pump is a core component of a mechanical lubrication system. Its function is to continuously circulate lubricating oil within the system, lubricating and cooling gears, bearings, and other components within the mechanical transmission system. Common industrial pump types include plunger pumps, gerotor pumps, and gear pumps. Gear pumps achieve oil suction and discharge through meshing gears. In a gear pump, the teeth of two gears on one side separate, creating a low pressure that draws liquid in and transports it through the casing to the other side. On the other side, the two gears close together, creating a high pressure that discharges the liquid. Gear pumps feature a compact structure, small size, lightweight, excellent processability, strong self-priming properties, insensitivity to oil contamination, a wide speed range, stable flow rates, easy maintenance, and reliable operation.
[0003] Traditionally, the interference fit assembly of bearing bushings in lubricating oil pump housing assemblies follows the following process: the housing is first heated, and the bushing is cooled in liquid oxygen / liquid nitrogen. The operator removes the cooled bushing from the liquid oxygen / liquid nitrogen with tweezers and then presses the bushing into the heated housing using a nylon rod and hammer. During this process, the bushing's bottom is tapped evenly along its circumference, and a feeler gauge is used to verify that the bushing is evenly fitted angularly. Due to the lack of a positioning reference during assembly, manual press-fitting can easily lead to misalignment between the bushing and the housing, and ensuring the bushing's verticality is difficult. Furthermore, when the bushing contacts the hot housing, heat conduction causes it to expand rapidly, which can cause it to become stuck in the bottom hole and prevent it from being fully pressed in. This makes the press-fitting process cumbersome and time-consuming, requiring extensive rework. Furthermore, when the operator taps the bushing's bottom evenly along its circumference with the hammer and nylon rod, the small base area and insufficient contact between the rod and the bushing create a safety risk of the rod slipping, potentially causing injury. Summary of the Invention
[0004] Purpose of the invention: To propose a gear pump bearing bushing interference assembly device and method, optimize the bushing interference assembly process of the gear pump housing assembly, improve assembly efficiency, stabilize assembly quality, simplify the operation process, and reduce safety risks.
[0005] Technical solution: A gear pump bearing bushing interference assembly device, comprising: a sleeve pressing fixture, a lever gauge, a fixture base, a verticality guide rail, and a gauge block; The fixture base is used to place the gear pump housing; the upper surface of the fixture base is provided with a vertical guide rail that matches the bushing mounting hole of the gear pump housing; The sleeve clamp is used to clamp the bushing; The lever gauge is fixed on the bushing clamp to detect whether the bushing is installed in place; The calibration block is used to calibrate the dial indicator.
[0006] Furthermore, the fixture base is a plate-like structure with locating pins on the upper surface for positioning the gear pump housing. Install the pump housing on the base and use a 0.02 feeler gauge to check the gap between the housing and the base along the perimeter of the assembly surface. The feeler gauge should not pass along the perimeter.
[0007] Furthermore, the sleeve pressing fixture is divided from top to bottom into: a clamping part, a lever gauge inlay part, a main body part and a sleeve installation part; The main body is a columnar structure; The clamping part includes an integrally formed disc-shaped platform and a columnar protrusion; the clamping part is connected to the main body through three evenly distributed columns; The lever meter inlay is a hollow cylindrical structure arranged at the top of the main body. The upper surface of the lever meter inlay is provided with a lever meter mounting groove, and the side is provided with a radial threaded hole, through which screws are passed to fix the lever meter. The bushing mounting portion is a columnar structure; two blind holes are symmetrically provided on the outer side of the bushing mounting portion, and the positions of the blind holes correspond to the inner grooves of the bushing; a spring is installed at the bottom of the blind hole, and a top ball is provided on the outside of the spring. The opening of the blind hole is a closing structure to prevent the top ball from falling out; The sleeve pressing fixture is provided with an axial through hole penetrating the lever gauge inlay portion, the main body portion and the bushing mounting portion.
[0008] Furthermore, the alignment block is a rectangular or circular block structure, with a through hole in the middle that matches the vertical guide rail, an upper surface size larger than the outer diameter of the bushing, a rigid structure, and a thickness equal to the distance between the bottom surface of the bushing mounting hole and the bottom surface of the gear pump housing.
[0009] Furthermore, the diameter of the main body is 10 mm larger than the bushing to be assembled, thereby ensuring the strength of the fixture and preventing interference with the gear pump housing during assembly.
[0010] Furthermore, the diameter of the bushing installation portion is 0.2 mm smaller than the inner diameter of the bushing to be assembled, which facilitates bushing installation.
[0011] Furthermore, the top ball is exposed by 0.5 mm from the outer side surface of the bushing installation portion in the natural state of the spring, and is used to clamp the bushing.
[0012] A gear pump bearing bushing interference assembly method comprises the following steps: Step 1: Heat the gear pump housing to 100±10℃ and keep it warm for 30 minutes; Step 2: 15 minutes after step 1, cool the bushing to be installed in a metal container filled with liquid oxygen or liquid nitrogen for 15 minutes; Step 3: Install the bushing on the sleeve clamp; Step 4: Calibrate the dial gauge; Step 5: Install the gear pump housing on the fixture base; Step 6: Insert the bushing into the gear pump housing and press it to the bottom of the hole; Step 7: Let the gear pump housing stand until it returns to room temperature.
[0013] Step 9: Disassemble the sleeve clamp and the clamp base.
[0014] Furthermore, the process of calibrating the lever gauge in step 4 is as follows: installing the gauge block on the verticality guide rail; Clamp the bushing to be installed with the sleeve clamp and move it downward along the vertical guide rail until the bottom surface of the bushing contacts the counter surface. Use a 0.02 feeler gauge to check along the periphery whether the bottom surface of the bushing and the counter block are tightly attached. If not, adjust the bushing until it is tightly attached. At this time, the stroke of the sleeve clamp is consistent with the stroke when the bushing is assembled to the bottom surface of the mounting hole. The probe of the lever gauge contacts and is subjected to force on the top surface of the verticality guide rail, and the needle deflects in the positive direction. At this time, rotate the dial scale panel of the lever gauge until the needle reading returns to zero.
[0015] Furthermore, in step seven, a lever press with a rated pressure of 2kN is used to clamp the sleeve clamp, and the bushing is pressed into the mounting hole through the vertical guide rail. The lever gauge reading is observed, and when the lever gauge reading returns to zero, the bushing is installed in place. The guide rail length ensures that when the bushing is pressed, the fixture lever gauge probe contacts and is subjected to force on the top surface of the guide rail, causing the needle to deflect in the positive direction by about 10 scale marks. Therefore, the probe contacts and is subjected to force on the top surface of the guide rail, and the needle deflects in the positive direction. At this time, rotate the dial scale panel until the needle reading returns to zero. When the bushing is actually assembled, the pointer points to zero, indicating that the bottom surface of the bushing is pressed.
[0016] Beneficial effects: 1. Improved efficiency: The traditional bushing interference fit assembly process requires using a nylon rod and hammer to evenly tap the bushing bottom along the circumference, and frequent feeler gauge verification is required to ensure the bushing is evenly assembled along all angular dimensions. With this invention, a press is used instead of manual tapping, and a lever gauge is used to ensure the bushing bottom is pressed against the bushing. This reduces the frequency of repeated assembly quality checks and improves production efficiency.
[0017] 2. Improved quality: Using a press instead of manual hammering for assembly ensures uniform and controllable pressure. Precise guidance and fixation by the fixture effectively ensures the coaxiality and perpendicularity between the bushing and the workpiece, significantly improving the quality of the press.
[0018] 3. Easy to operate: Using mechanized operation instead of the original manual knocking operation makes the sleeve pressing process simpler, reduces the difficulty of operation, and reduces the skill requirements for operators.
[0019] 4. Improved safety: It reduces the potential safety hazards brought by traditional knocking methods and improves operational safety. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The present invention provides a schematic flow chart of the bushing interference assembly method.
[0021] Figure 2 This is a schematic structural diagram of the comprehensive fixture platform provided by the present invention.
[0022] Figure 3 This is a schematic diagram of the operation of the bushing interference assembly method provided by the present invention.
[0023] Figure 4 This is a schematic diagram of the dial of a lever meter.
[0024] Description of reference numerals: 1—pressing fixture, 2—top ball, 3—spring, 4—lever gauge probe, 5—lever gauge dial, 6—lever gauge fastening screw, 7—clamp base, 8—locating pin, 9—verticality guide rail, 10—meter block, 11—pump housing, 12—bushing. DETAILED DESCRIPTION
[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0026] A gear pump bearing bushing interference fit assembly device includes a sleeve pressing fixture 1, a top ball 2, a spring 3, a lever gauge probe 4, a lever dial 5, a lever gauge fastening screw 6, a fixture base 7, a positioning pin 8, a verticality guide rail 9, and a gauge block 10.
[0027] The sleeve clamp 1 can be divided into four parts from top to bottom: the press holding part, the lever gauge embedding part, the main body, and the bushing installation part. The main body is a columnar structure with a diameter 10mm larger than the bushing to be assembled, which ensures the strength of the clamp while ensuring that there is no interference with the pump housing during assembly. The press holding part consists of a disc-shaped platform and a columnar protrusion at the top that matches the press, and is connected to the main body through three columns. The lever gauge embedding part is a columnar structure at the top of the main body, with a groove on the top surface for embedding the lever dial, and radial threaded holes on the side for installing the lever gauge fastening screws. The bushing installation part is a columnar structure at the bottom of the main body, with a diameter 0.2mm smaller than the inner diameter of the bushing 12 to be assembled, and two radial blind holes on the side for embedding the spring 3 and the top ball 2. The bushing installation part of the sleeve clamp is closed after embedding the spring 3 and the top ball 2 to prevent the top ball 2 from falling out. The top ball protrudes 0.5mm from the side of the clamp in its free state. In addition, a through hole is opened on the axis of the fixture to match the verticality guide rail 9 with clearance, and passes through the lever meter inlay part, the main body part and the bushing installation part.
[0028] Lever dial 5 style as Figure 4 As shown. After the lever dial is inserted into the fixture and tightened with the fastening screws, the stylus is introduced into the through hole from the bottom of the groove where the dial is mounted. During bushing assembly, the stylus contacts the guide rail surface and applies pressure, causing the needle to deflect in the positive direction. The pressed-in state of the bushing is determined by the dial reading. When calibrating the lever dial, rotate the dial scale panel until the needle reading returns to zero. After calibration, the needle reading in the free state should be negative. During bushing assembly, when the stylus contacts the top surface of the guide rail, the stylus is subjected to pressure, which is transmitted to the dial needle. As the bushing moves downward, the stylus pressure increases, and the needle reading gradually increases until the bushing reaches the desired assembly state at the reading of zero.
[0029] The main body of the fixture base 7 is a flat rectangular platform. A locating pin 8 is installed at the corresponding position of the locating pin hole of the pump housing 11 to position the pump housing 11, and a verticality guide rail 9 is installed at the axial center position of the two bushing bottom holes of the pump housing 11. The length of the guide rail ensures that when the bushing is pressed, the measuring needle of the fixture lever gauge contacts the top surface of the guide rail and is subjected to force, so that the needle deflects in the positive direction by about 10 scale marks.
[0030] The clamping fixture is equipped with a table block 10, which is a rectangular block structure with a through hole in the center that fits the vertical guide rail 9. The thickness is equal to the distance between the bottom surface of the bottom hole of the pump housing 11 and the bottom surface of the part (i.e. Figure 3Dimension A shown). Use the gauge block 10 to calibrate the lever gauge before assembly. Install the bushing 12 on the sleeve clamp 1, pass the center hole of the gauge block 10 through the guide rail 9 and place it on the base 7. The sleeve clamp 1 is lowered along the guide rail 9 until the bottom surface of the bushing contacts the gauge block 10. Use a 0.02 feeler gauge to check along the periphery whether the bottom surface of the bushing and the gauge block are tightly attached. The feeler gauge should not pass along the periphery. At this time, the stroke of the clamp 1 is consistent with the stroke when the bushing 12 is assembled to the bottom surface of the housing 11 and pressed. The probe contacts and is subjected to force on the top surface of the guide rail, and the pointer deflects in the positive direction. At this time, rotate the dial scale panel until the pointer reading returns to zero. When the bushing is actually assembled, the pointer points to zero, indicating that the bottom surface of the bushing is pressed.
[0031] When assembling the bushing, first heat the pump housing and use liquid oxygen or liquid nitrogen to cool the bushing. Before assembling the bushing, it is necessary to calibrate the lever gauge using a gauge block, and then mount the bushing on the pressing fixture, ensuring that the top ball is fixed in the ring groove position of the bushing inner diameter. Install the heated pump housing on the base at room temperature, use a lever press with a rated pressure of 2kN to hold the pressing fixture, press the bushing into the bottom hole of the housing through the guide rail, and determine whether the bottom surface of the bushing fits the housing by checking whether the reading of the lever dial embedded in the pressing fixture is zero. After the assembled components are left to stand at room temperature, the bushing returns to room temperature and expands in volume, and the top ball of the pressing fixture is loosened from the ring groove position. At this time, the pressing fixture can be removed.
[0032] Figure 1 This is a flow chart of the bushing interference assembly method provided by the present invention. Figure 1 The bushing interference assembly method provided by the present invention includes: Step 1: Heat the pump housing The operator places the pump housing to be assembled into a heating furnace, heats the housing to 100±10℃ and keeps it warm for 30 minutes.
[0033] Step 2: Cooling Bushing 15 minutes after starting step 1, place the two bushings in a metal container filled with liquid oxygen or liquid nitrogen and cool for 15 minutes.
[0034] Step 3: Install the bushing on the fixture Use tweezers to take out the two cooled bushings, and press the bushing clamps into the inner diameter of each bushing to ensure that the top ball is firmly seated in the inner groove of the bushing.
[0035] Step 4: Calibrate the dial gauge Calibrate the lever gauge on each of the two bushing pressing fixtures. Place the gauge block on the base, lower the pressing fixture along the guide rail until it contacts the bushing bottom surface with the gauge block, and calibrate the lever gauge dial to zero.
[0036] Step 5: Install the pump housing on the base Take out the heated pump housing and cool it to room temperature. Figure 3 Insert the two vertical guide rails on the base through the bottom holes of the casing bushing in the direction shown. Use the locating pin holes on the base to locate the pump casing on the base. Use a 0.02 feeler gauge to check the gap between the casing and the base along the perimeter of the assembly surface. The feeler gauge should not pass along the perimeter.
[0037] Step 6: Install the bushing into the pump housing Use a press to clamp the sleeve clamp and insert the bushing into the bottom hole of the shell through the guide rail.
[0038] Step 7: Press the bushing to the bottom of the hole Use a press to press the two bushings down until the fixture lever indicator shows 0.
[0039] Step 8: Let the pump housing stand Allow the pump housing to cool to room temperature.
[0040] Step 9: Disassemble the sleeve clamp and the clamp base Release the press clamp. Remove the pump housing, which has been allowed to cool to room temperature, from the clamp base. Then, pull the sleeve clamp upwards out of the pump housing.
[0041] The above description is merely a detailed description of specific embodiments of the present invention. Any unspecified portions are conventional techniques. However, the scope of the present invention is not limited thereto. Any changes or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed in the present invention are intended to be encompassed within the scope of the present invention. The scope of the present invention shall be determined by the scope of the claims.
Claims
1. A gear pump bearing bushing interference fit device, characterized by: The device comprises: a sleeve pressing fixture, a lever gauge, a fixture base, a verticality guide rail, and a gauge block; The fixture base is used to place the gear pump housing; the upper surface of the fixture base is provided with a vertical guide rail that matches the bushing mounting hole of the gear pump housing; The sleeve clamp is used to clamp the bushing; The lever gauge is fixed on the bushing clamp to detect whether the bushing is installed in place; The calibration block is used to calibrate the dial indicator.
2. The device according to claim 1, characterized in that: The fixture base is a plate-shaped structure, and a positioning pin is provided on the upper surface for positioning the gear pump housing.
3. The device according to claim 1, characterized in that: The sleeve clamp is divided from top to bottom into: clamping part, lever gauge inlay part, main body part and sleeve installation part; The main body is a columnar structure; The clamping part includes an integrally formed disc-shaped platform and a columnar protrusion; the clamping part is connected to the main body through three evenly distributed columns; The lever meter inlay is a hollow cylindrical structure arranged at the top of the main body. The upper surface of the lever meter inlay is provided with a lever meter mounting groove, and the side is provided with a radial threaded hole, through which screws are passed to fix the lever meter. The bushing mounting portion is a columnar structure; two blind holes are symmetrically provided on the outer side of the bushing mounting portion, and the positions of the blind holes correspond to the inner grooves of the bushing; a spring is installed at the bottom of the blind hole, and a top ball is provided on the outside of the spring. The opening of the blind hole is a closing structure to prevent the top ball from falling out; The sleeve pressing fixture is provided with an axial through hole penetrating the lever gauge inlay portion, the main body portion and the bushing mounting portion.
4. The device according to claim 3, characterized in that: The table block is a rectangular or circular block structure with a through hole in the middle that matches the vertical guide rail. The upper surface size is larger than the outer diameter of the bushing and it has a rigid structure. The thickness is equal to the distance between the bottom surface of the bushing mounting hole and the bottom surface of the gear pump housing.
5. The device according to claim 4, characterized in that: The diameter of the main body is 10 mm larger than the bushing to be assembled.
6. The device according to claim 5, characterized in that: The diameter of the bushing installation part is 0.2mm smaller than the inner diameter of the bushing to be assembled.
7. The device according to claim 6, characterized in that: When the spring is in its natural state, the top ball protrudes 0.5mm from the outer side of the bushing mounting portion.
8. A method for interference fitting a gear pump bearing bushing, implemented based on the device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Heat the gear pump housing to 100±10℃ and keep it warm for 30 minutes; Step 2: 15 minutes after step 1, cool the bushing to be installed in a metal container filled with liquid oxygen or liquid nitrogen for 15 minutes; Step 3: Install the bushing on the sleeve clamp; Step 4: Calibrate the dial gauge; Step 5: Install the gear pump housing on the fixture base; Step 6: Insert the bushing into the gear pump housing and press it to the bottom of the hole; Step 7: Let the gear pump housing stand until it returns to room temperature. Step 9: Disassemble the sleeve clamp and the clamp base.
9. The method according to claim 8, characterized in that: The process for calibrating the lever gauge in step 4 is as follows: Install the gauge block on the verticality guide rail; Clamp the bushing to be installed with the sleeve clamp and move it downward along the vertical guide rail until the bottom surface of the bushing contacts the counter surface. Use a 0.02 feeler gauge to check along the periphery whether the bottom surface of the bushing and the counter block are tightly attached. If not, adjust the bushing until it is tightly attached. At this time, the stroke of the sleeve clamp is consistent with the stroke when the bushing is assembled to the bottom surface of the mounting hole. The probe of the lever gauge contacts and is subjected to force on the top surface of the verticality guide rail, and the needle deflects in the positive direction. At this time, rotate the dial scale panel of the lever gauge until the needle reading returns to zero.
10. The device according to claim 9, characterized in that: In step seven, use a lever press with a rated pressure of 2kN to clamp the sleeve clamp, press the bushing into the mounting hole through the vertical guide rail, observe the lever gauge reading, and when the lever gauge reading returns to zero, the bushing is installed in place.