Gear pump

Abstract

The utility model relates to the technical field of pump valves, in particular to a gear pump which comprises a cylinder body, a containing cavity is arranged on the cylinder body, a liquid inlet flow channel and a liquid outlet flow channel are arranged on the cylinder body, one end of the liquid inlet flow channel and one end of the liquid outlet flow channel are both communicated with the containing cavity, a driving shaft is arranged in the containing cavity in a rotating mode, and a driving gear is arranged on the driving shaft. The driving gear is meshed with the driven gear, a shaft hole is formed in the center of the driving gear, the driving shaft is in interference fit with the shaft hole, the driving shaft is sleeved with a fixed-core shaft sleeve, the fixed-core shaft sleeve is fixed to the cylinder body, and the driving shaft is in interference fit with the central shaft hole of the driving gear, so that high coaxiality between the driving shaft and the driving gear is guaranteed; the pump body vibration risk caused by eccentricity of the driving gear in the rotating process is reduced, the position precision of the driving shaft relative to the cylinder body is guaranteed, the driving gear and the driven gear can be kept in a stable meshing state during working, and shaking and deflection of the gears caused by instability of the driving shaft are reduced.

Description

Technical Field

[0001] This utility model relates to the field of pump and valve technology, and in particular to a miniature gear pump. Background Technology

[0002] In applications involving corrosive liquids, such as miniature gear pumps in printers, the performance and reliability of gear pumps are crucial. As a common type of positive displacement pump, the gear pump operates on the principle of gear meshing and disengaging, using the rotation of the gears to achieve the intake and discharge of liquids.

[0003] In some existing gear pump designs, there are significant problems with the fit between the drive shaft and the drive gear. As a key component for power transmission, the drive shaft often uses a flat connection with the drive gear. When using a flat connection, it's difficult to guarantee precise concentricity when the drive gear rotates at high speed. In mechanical manufacturing, concentricity is a crucial indicator of the degree of alignment between the axes of two rotating bodies. When the concentricity deviation between the drive shaft and the drive gear is large, the actual rotation center of the drive gear will deviate from its theoretical rotation center during rotation, leading to eccentricity. This eccentricity causes unbalanced centrifugal force during pump operation, resulting in pump body vibration. Simultaneously, the uneven contact between the gear and the pump body caused by eccentricity easily leads to scraping and wear, and in severe cases, can even cause the gear to seize, rendering the gear pump malfunctioning.

[0004] Furthermore, the fit between the cylinder block and the bottom cover also significantly impacts the performance of the gear pump. In actual production, due to manufacturing limitations, tolerances are unavoidable between the cylinder block and the bottom cover. To ensure smooth rotation of the drive shaft and gears, similar products typically cannot set the clearance too small when designing the fit between the holes in the cylinder block and bottom cover that secure the drive shaft. A larger clearance results in insufficient restraint on the gears during operation, making them prone to wobbling and runout. This wobbling and runout further exacerbates uneven wear between the gears and internal pump components, increasing the risk of gear jamming and severely affecting the service life and operational stability of the gear pump in corrosive liquid environments. Utility Model Content

[0005] The purpose of this utility model is to provide a gear pump that solves the problem of eccentricity between the drive shaft and the gear in the gear pump mentioned above, as well as the problem of the cylinder body constraining the drive shaft, thereby eliminating shaking and wobbling phenomena.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A gear pump, comprising:

[0008] A cylinder body, having a receiving chamber, an inlet channel and an outlet channel, one end of which is connected to the receiving chamber;

[0009] A drive shaft is rotatably disposed within the receiving cavity, and a drive mechanism drives the drive shaft to rotate.

[0010] A drive gear is mounted on the drive shaft;

[0011] Driven gear, the driving gear meshes with the driven gear, the liquid inlet channel and the liquid outlet channel are respectively located on both sides of the engagement of the driving gear and the driven gear;

[0012] The drive gear has a central hole, the drive shaft is inserted into the hole, the drive shaft is press-fitted with the hole, and a centering sleeve is fitted around the drive shaft and fixed to the cylinder body.

[0013] This utility model also has the following technical features:

[0014] In one embodiment of this utility model, the shaft hole of the drive gear is circular, and the cross-section of the drive shaft is circular.

[0015] In one embodiment of the present invention, the driven gear is provided with a driven shaft hole at its center, and a driven shaft is provided in the driven shaft hole. The driven shaft and the driven shaft hole are interference-fitted.

[0016] In one embodiment of this utility model, the cylinder body is provided with an adapter, the adapter is provided with an inlet and an outlet, the inlet channel is connected to the inlet, the outlet channel is connected to the outlet, and the outlet channel is arranged above the inlet channel.

[0017] In one embodiment of the present invention, the outer wall of the cylinder is provided with a groove, the bottom of the groove is provided with a hole for the drive shaft to pass through, the mandrel sleeve is inserted into the groove, and a sealing sleeve is fitted on the drive shaft, the sealing sleeve extends into the inner cavity of the groove and its outer wall abuts against the inner wall of the groove.

[0018] In one embodiment of the present invention, a top cover is detachably provided on one side of the cylinder body, and a sealing ring is provided on the contact surface between the top cover and the cylinder body, and the receiving chamber is located in the area of ​​the sealing ring.

[0019] In one embodiment of this utility model, a drive internal gear ring is fixed to one end of the drive shaft extending out of the cylinder body, and a drive gear is engaged with the drive internal gear ring. A bottom cover is provided on the cylinder body, and the drive mechanism includes a drive motor disposed on the bottom cover. The output shaft of the drive motor is connected to the drive gear.

[0020] In one embodiment of the present invention, a positioning plug and a positioning groove are provided on the side of the cylinder body, and a corresponding plug-in piece and a plug interface are provided on the bottom cover. The positioning plug is inserted into the plug interface, and the plug-in piece is inserted into the positioning groove.

[0021] In one embodiment of this utility model, a first insertion pipe is provided at the position where the liquid outlet channel extends out of the outer wall of the cylinder body, and a second insertion pipe is provided at the position where the liquid inlet channel extends out of the outer wall of the cylinder body. Two sets of insertion slots are provided on the adapter. Rubber rings are provided at the ends of the first insertion pipe and the second insertion pipe. The first insertion pipe and the second insertion pipe are respectively inserted into the two sets of insertion slots, and the rubber rings abut against the bottom of the insertion slots.

[0022] In one embodiment of this utility model, the adapter is provided with a mounting hole, and a fastening bolt is provided in the mounting hole. The fastening bolt is connected to the outer wall of the cylinder.

[0023] Compared with existing technologies, the beneficial effects of this utility model are reflected in:

[0024] By setting the drive shaft and the central shaft hole of the drive gear to an interference fit, the elastic deformation of the material between the shaft and the hole after assembly will generate a certain pressure, thereby ensuring a high degree of coaxiality between the two and greatly reducing the risk of pump body vibration caused by eccentricity during the rotation of the drive gear. At the same time, a mandrel bushing fixed on the cylinder block is installed on the drive shaft to further position and support the drive shaft. This ensures the precise concentricity of the drive shaft and the drive gear from multiple aspects, effectively avoiding scraping wear and jamming caused by eccentricity, and significantly improving the stability and reliability of the gear pump operation.

[0025] The mandrel bushing is fixed to the cylinder block, providing stable support for the drive shaft and limiting its radial displacement during operation. Even with tolerances between the cylinder block and the bottom cover, the mandrel bushing ensures the positional accuracy of the drive shaft relative to the cylinder block, thereby maintaining a stable meshing state between the drive gear and the driven gear during operation. This reduces gear wobble and runout caused by drive shaft instability. This not only reduces wear on the gears and other internal components of the pump body, extending the service life of the gear pump, but also enables the gear pump to operate more smoothly when conveying corrosive liquids, ensuring the stability of liquid flow and pressure.

[0026] The aforementioned structural design effectively solves key problems existing in current gear pumps used in corrosive liquid applications, such as difficulty in ensuring concentricity and gear wobble caused by fit tolerances. Overall, it improves the performance of gear pumps in corrosive liquid environments, enabling them to adapt to more complex and harsh working conditions. It also enhances the reliability of miniature gear pumps in devices such as printers, reduces the frequency of equipment maintenance and parts replacement, lowers operating costs, and provides strong technical support for the wider application of gear pumps in corrosive liquid fields. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the gear pump structure in one embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the gear pump after it has been removed from the drive motor in one embodiment of the present invention;

[0029] Figure 3 and Figure 4 These are schematic diagrams of the gear pump after it has been removed from the drive motor and the bottom cover in one embodiment of the present invention.

[0030] Figure 5 and Figure 6 These are schematic diagrams of the cylinder body from two different perspectives in one embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the adapter nozzle in one embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the bottom cover structure in one embodiment of the present invention;

[0033] Figure 9 This is a cross-sectional view of the cylinder block, drive shaft, drive gear, driven gear, and driven shaft assembly in one embodiment of the present invention.

[0034] Explanation of icon numbers:

[0035] 10. Cylinder body; 11. Receiving chamber; 111. Inlet channel; 1111. Second connector; 112. Outlet channel; 1121. First connector; 12. Settling tank; 13. Drive internal gear ring; 14. Drive gear; 15. Positioning plug; 16. Positioning groove;

[0036] 20. Drive shaft;

[0037] 30. Drive gear;

[0038] 40. Driven gear; 41. Driven shaft;

[0039] 50. Stator bushing; 51. Sealing sleeve;

[0040] 60. Adapter nozzle; 61. Liquid inlet nozzle; 62. Liquid outlet nozzle; 63. Insert slot; 64. Fastening bolt;

[0041] 70. Top cover; 71. Sealing ring;

[0042] 80. Bottom cover; 81. Drive motor; 82. Connector piece; 83. Connector interface. Detailed Implementation

[0043] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0044] The illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0045] It should be noted that some existing gear pump designs have significant problems with the fit between the drive shaft and the drive gear. As a key component for power transmission, the drive shaft often uses a flat connection with the drive gear. When using a flat connection, it's difficult to guarantee precise concentricity when the drive gear rotates at high speed. In mechanical manufacturing, concentricity is a crucial indicator of the degree of alignment between the axes of two rotating bodies. When the concentricity deviation between the drive shaft and the drive gear is large, the actual rotation center of the drive gear will deviate from the theoretical rotation center during gear rotation, leading to eccentricity. This eccentricity causes unbalanced centrifugal force during operation, resulting in pump vibration. Simultaneously, the uneven contact between the gear and the pump body caused by eccentricity easily leads to scraping and wear, and in severe cases, even gear jamming, rendering the gear pump malfunctioning. Furthermore, the fit between the cylinder block and the bottom cover also significantly affects the performance of the gear pump. In actual production, due to manufacturing limitations, tolerances are unavoidable between the cylinder block and the bottom cover. To ensure smooth rotation of the drive shaft and gears, similar products typically cannot set the clearance too small when designing the fit between the holes that secure the drive shaft in the cylinder block and bottom cover. A large clearance results in insufficient restraint on the gears during operation, making them prone to wobbling and runout. This wobbling and runout further exacerbates uneven wear between the gears and internal pump components, increasing the risk of gear jamming and severely impacting the service life and operational stability of the gear pump in corrosive liquid environments. A gear pump is proposed, comprising: a cylinder body 10, a receiving chamber 11 provided on the cylinder body 10, an inlet channel 111 and an outlet channel 112 provided on the cylinder body 10, one end of the inlet channel 111 and the outlet channel 112 being connected to the receiving chamber 11; a drive shaft 20, rotatably disposed within the receiving chamber 11, and a drive mechanism driving the drive shaft 20 to rotate; a driving gear 30 disposed on the drive shaft 20; and a driven gear 40, the driving gear 30 meshing with the driven gear 40, the inlet channel 111 and the outlet channel 112 being respectively located on both sides of the engagement of the driving gear 30 and the driven gear 40; wherein, the driving gear 30 has a shaft hole at its center, the drive shaft 20 is inserted into the shaft hole with an interference fit, and a centering sleeve 50 is fitted over the drive shaft 20, the centering sleeve 50 being fixed to the cylinder body 10.

[0046] In one embodiment, see Figure 9 The drive shaft 20 can be made of corrosion-resistant metal material. The drive shaft 20 and the drive gear 30 are interference-fitted. Due to the elastic deformation of the material, a certain pressure will be generated between the shaft and the hole, thereby ensuring that the two have a high degree of coaxiality and greatly reducing the risk of pump body vibration caused by eccentricity during the rotation of the drive gear.

[0047] In one embodiment, the mating surface between the drive shaft 20 and the drive gear 30 can be a smooth surface, a frosted surface, or a rolled surface.

[0048] In one embodiment, see Figure 9 The drive gear 30 can be made of corrosion-resistant engineering plastic. When the drive shaft 20 is inserted into the shaft hole of the drive gear 30, the drive gear 30 may expand, making the outer diameter of the drive gear 30 too large. In response, the actual expansion ratio is converted to make the drive gear smaller than the driven gear. After being pressed into the drive shaft, the drive gear 30 will be enlarged to make its diameter equal to that of the driven gear 40.

[0049] In one embodiment, the mandrel sleeve 50 can be made of corrosion-resistant plastic or metal material. The mandrel sleeve 50 and the drive shaft 20 can be clearance-fitted. The drive shaft 20 is rotatably disposed in the mandrel sleeve 50, providing stable support for the drive shaft and limiting the radial displacement of the drive shaft during operation.

[0050] In one embodiment, see Figure 6 The inlet channel 111 and the outlet channel 112 are holes formed on the cylinder body 10. The holes are curved, meandering, or straight, and are respectively located on both sides of the engagement of the driving gear 30 and the driven gear 40. When the driving gear 30 drives the driven gear 40 to rotate, the volume of the space on the disengaged side of the gear increases from small to large, forming a vacuum, which draws the liquid in from the inlet channel 111. The volume of the space on the meshing side of the gear decreases from large to small, which squeezes the liquid into the outlet channel 112.

[0051] In one embodiment, the shaft hole of the drive gear 30 is circular, and the cross-section of the drive shaft 20 is circular. When the circular shaft and the hole are engaged, the coaxiality of the drive shaft 20 and the drive gear 30 can be ensured.

[0052] In one embodiment, the driven gear 40 has a driven shaft hole at its center, and a driven shaft 41 is disposed in the driven shaft hole, with the driven shaft 41 and the driven shaft hole being interference-fitted.

[0053] In one embodiment, the driven shaft 41 is made of a corrosion-resistant metal or plastic material, and the driven gear 40 is made of a corrosion-resistant polymer plastic material. When the driven shaft 41 and the driven gear 40 are engaged, the coaxiality between the driven gear 40 and the driven shaft 41 can also be ensured.

[0054] In one embodiment, the driven gear 40 has a circular shaft hole and the driven shaft 41 has a circular cross-section. When the circular shaft and the hole are fitted together, the coaxiality of the driven gear 40 and the driven shaft 41 can be ensured.

[0055] Similarly, the mating surface between the driven shaft 41 and the driving gear 30 can be a smooth surface, a frosted surface, or a knurled surface.

[0056] In one embodiment, see Figures 1 to 3 The cylinder body 10 is provided with an adapter 60, the adapter 60 is provided with an inlet 61 and an outlet 62, the inlet channel 111 is connected to the inlet 61, the outlet channel 112 is connected to the outlet 62, and the outlet channel 112 is arranged above the inlet channel 111.

[0057] In one embodiment, the inlet channel 111 and the outlet channel 112 are straight holes formed on the cylinder body 10, and the outlet channel 112 is arranged above the inlet channel 111. This allows the water intake method of the gear pump to be changed from top water intake to middle or bottom water intake, ensuring that the gear gap can be completely filled with liquid and no air bubbles are formed. When the channel pressure is too high, the seal fails, causing the water inlet and outlet circuits to connect and leak internally. An adapter 60 is added. According to the usage requirements, when the gear pump is installed, the inlet channel 111 is located below the outlet channel 112, which facilitates the adjustment of the water inlet and outlet directions.

[0058] In one embodiment, to ensure a seal between the drive shaft 20 and the cylinder 10, the outer wall of the cylinder 10 is provided with a groove 12, the bottom of the groove 12 is provided with a hole for the drive shaft 20 to pass through, the centering sleeve 50 is inserted into the groove 12, and a sealing sleeve 51 is fitted on the drive shaft 20, the sealing sleeve 51 extends into the inner cavity of the groove 12 and its outer wall abuts against the inner wall of the groove 12.

[0059] In one embodiment, see Figure 4 The cylinder body 10 is provided with a detachable top cover 70 on one side. A sealing ring 71 is provided on the mating surface of the top cover 70 and the cylinder body 10. The receiving chamber 11 is located in the area of ​​the sealing ring 71.

[0060] In one embodiment, fastening holes are provided around the top cover 70, and screws are installed in the fastening holes. The screws are used to fix the top cover 70 to the cylinder 10. After the top cover 70 is fixed to the cylinder 10, the sealing ring 71 can ensure the seal between the top cover 70 and the cylinder 10.

[0061] Preferably, see Figure 3 The drive shaft 20 extends out of the cylinder body 10 and is fixed with a drive internal gear ring 13. The drive internal gear ring 13 is meshed with a drive gear 14. The cylinder body 10 is provided with a bottom cover 80. The drive mechanism includes a drive motor 81 provided on the bottom cover 80. The output shaft of the drive motor 81 is connected to the drive gear 14.

[0062] In one embodiment, see Figure 3 One end of the drive shaft 20 is connected to the center of the drive internal gear ring 13 by a keyway, which enables a detachable connection between the drive internal gear ring 13 and the drive shaft 20. The drive internal gear ring 13 is used in conjunction with the drive gear 14 to reduce the speed of the motor and increase the torque, thereby reducing the risk of jamming.

[0063] In one embodiment, see Figure 5 and Figure 8 To ensure accurate installation between the bottom cover 80 and the cylinder body 10, a positioning plug 15 and a positioning groove 16 are provided on the side of the cylinder body 10. The bottom cover 80 is provided with a corresponding plug-in piece 82 and a plug-in interface 83. The positioning plug 15 is inserted into the plug-in interface 83, and the plug-in piece 82 is inserted into the positioning groove 16.

[0064] In one embodiment, see Figure 5 and Figure 7 To ensure reliable communication between the liquid outlet channel 112 and the liquid inlet channel 111 and the adapter 60, a first insertion pipe 1121 is provided at the position where the liquid outlet channel 112 extends out of the outer wall of the cylinder body 10, and a second insertion pipe 1111 is provided at the position where the liquid inlet channel 111 extends out of the outer wall of the cylinder body 10. The adapter 60 is provided with two sets of insertion slots 63. Rubber rings are provided at the ends of the first insertion pipe 1121 and the second insertion pipe 1111. The first insertion pipe 1121 and the second insertion pipe 1111 are respectively inserted into the two sets of insertion slots 63, and the rubber rings abut against the bottom of the insertion slots 63.

[0065] In one embodiment, to enable the installation between the adapter 60 and the cylinder 10, the adapter 60 is provided with an installation hole, and a fastening bolt 64 is provided in the installation hole, the fastening bolt 64 being connected to the outer wall of the cylinder 10.

[0066] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0067] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A gear pump, characterized in that, include: The cylinder (10) has a receiving chamber (11) and an inlet flow channel (111) and an outlet flow channel (112) provided on the cylinder (10). One end of the inlet flow channel (111) and the outlet flow channel (112) are connected to the receiving chamber (11). A drive shaft (20) is rotatably disposed within the receiving chamber (11), and a drive mechanism drives the drive shaft (20) to rotate. A drive gear (30) is disposed on the drive shaft (20); Driven gear (40), driven gear (30) meshes with driven gear (40), liquid inlet channel (111) and liquid outlet channel (112) are respectively located on both sides of the engagement of driven gear (30) and driven gear (40); The drive gear (30) has a shaft hole at its center, the drive shaft (20) is inserted into the shaft hole, the drive shaft (20) is interference-fitted with the shaft hole, and the drive shaft (20) is fitted with a centering sleeve (50), which is fixed on the cylinder body (10).

2. The gear pump according to claim 1, characterized in that: The shaft hole of the drive gear (30) is circular, and the cross section of the drive shaft (20) is circular.

3. The gear pump according to claim 1, characterized in that: The driven gear (40) has a driven shaft hole at its center, and a driven shaft (41) is provided in the driven shaft hole. The driven shaft (41) is interference-fitted with the driven shaft hole.

4. The gear pump according to claim 1, characterized in that: The cylinder body (10) is provided with an adapter (60), the adapter (60) is provided with an inlet (61) and an outlet (62), the inlet channel (111) is connected to the inlet (61), the outlet channel (112) is connected to the outlet (62), and the outlet channel (112) is arranged above the inlet channel (111).

5. The gear pump according to claim 1, characterized in that: The outer wall of the cylinder (10) is provided with a sinker (12), and the bottom of the sinker (12) is provided with a hole for the drive shaft (20) to pass through. The centering sleeve (50) is inserted into the sinker (12), and a sealing sleeve (51) is fitted on the drive shaft (20). The sealing sleeve (51) extends into the inner cavity of the sinker (12) and its outer wall abuts against the inner wall of the sinker (12).

6. The gear pump according to claim 1, characterized in that: The cylinder body (10) is provided with a detachable top cover (70) on one side. The upper cover (70) and the cylinder body (10) are provided with a sealing ring (71) on their contact surface. The receiving chamber (11) is located in the area of ​​the sealing ring (71).

7. The gear pump according to claim 1, characterized in that: One end of the drive shaft (20) extending out of the cylinder (10) is fixed with a drive internal gear ring (13), and the drive internal gear ring (13) is meshed with a drive gear (14). A bottom cover (80) is provided on the cylinder (10), and the drive mechanism includes a drive motor (81) provided on the bottom cover (80). The output shaft of the drive motor (81) is connected to the drive gear (14).

8. The gear pump according to claim 7, characterized in that: The cylinder body (10) is provided with a positioning plug (15) and a positioning groove (16) on its side. The bottom cover (80) is provided with a plug-in piece (82) and a plug-in interface (83). The positioning plug (15) is inserted into the plug-in interface (83), and the plug-in piece (82) is inserted into the positioning groove (16).

9. The gear pump according to claim 4, characterized in that: The liquid outlet channel (112) is provided with a first insertion pipe (1121) extending out of the outer wall of the cylinder body (10), and the liquid inlet channel (111) is provided with a second insertion pipe (1111) extending out of the outer wall of the cylinder body (10). The adapter (60) is provided with two sets of insertion slots (63). The ends of the first insertion pipe (1121) and the second insertion pipe (1111) are provided with rubber rings. The first insertion pipe (1121) and the second insertion pipe (1111) are respectively inserted into the two sets of insertion slots (63), and the rubber rings abut against the bottom of the insertion slots (63).

10. The gear pump according to claim 9, characterized in that: The adapter (60) is provided with a mounting hole, and a fastening bolt (64) is provided in the mounting hole. The fastening bolt (64) is connected to the outer wall of the cylinder (10).

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