Gearbox for grease gun

Abstract

The utility model discloses a gear box for grease injector belongs to gear drive device technical field. It is equipped with rear casing and front casing, and rear casing and front casing are fixedly connected through buckle structure and form containing space, and the connecting place of rear casing and front casing is equipped with the structure of stopping mouth, and the gear group is equipped in containing space, and the mounting shaft is equipped on rear casing, and the drive motor is equipped on front casing, and the output shaft of drive motor stretches into containing space and cooperates with gear group, and rear casing and front casing are integrally formed, and integrally formed have gear spacer sleeve. The utility model discloses through integrally formed casing to guarantee mounting hole concentric, and buckle connection simplifies assembly, and gear spacer sleeve integration reduces parts, and the structure of stopping mouth improves connection accuracy, and guarantees gear box operation stability.

Description

Technical Field

[0001] This utility model relates to the technical field of gear transmission devices, specifically to a gearbox for a grease injector. Background Technology

[0002] Gearboxes, as transmission devices that transmit power from drive motors to actuators, are widely used in small automated equipment such as grease dispensers. In grease dispensers, the push structure at the gearbox output end drives a plunger-type check valve to reciprocate through mating parts, thereby achieving a quantitative output of lubricating grease.

[0003] Existing gearboxes for grease injectors typically consist of upper and lower side plates, multiple gears, gear fixing posts, mounting shafts, and a drive motor. The upper and lower side plates are formed separately from galvanized steel sheets through a stamping process, with mounting holes then drilled into each plate. Due to unavoidable springback and warping deformation during the stamping process, it's difficult to ensure perfect concentricity of the mounting holes on the upper and lower side plates. When the gear shaft or fixing post passes through the corresponding hole, misalignment can lead to assembly difficulties, sometimes requiring external force to press it in, thus affecting gear meshing accuracy and transmission stability. Furthermore, the upper and lower side plates are connected by multiple threaded posts and screws, resulting in a large number of parts and complex assembly steps. The gear spacers, as independent parts, must be assembled individually onto the gear fixing posts, further increasing the number of parts and assembly steps.

[0004] Therefore, there is a need for a gearbox for grease injectors that can reduce the number of parts, simplify the assembly process, and ensure the stability of the housing during use. Utility Model Content

[0005] This utility model aims to solve the problems of misaligned holes, numerous connecting parts, and cumbersome assembly caused by separate machining of the upper and lower side plates in existing gearboxes for grease injectors, while ensuring the stability of the gearbox during use.

[0006] To solve the above-mentioned technical problems, this utility model provides a gearbox for a grease injector, which has a rear housing and a front housing. The rear housing and the front housing are fixedly connected by a snap-fit ​​structure to form a receiving space. A stop structure is provided at the connection between the rear housing and the front housing. A gear set is provided in the receiving space. A mounting shaft is provided on the rear housing. A drive motor is provided on the front housing. The output shaft of the drive motor extends into the receiving space and cooperates with the gear set. The rear housing and the front housing are both integrally formed and have an integrally formed gear spacer.

[0007] Furthermore, the front housing edge is provided with a retaining ring, and the rear housing edge is provided with a retaining groove. The retaining ring and the retaining groove cooperate to achieve fastening and locking.

[0008] Furthermore, the retaining ring has a groove-in-groove protrusion, and the retaining groove has a corresponding recess, with the groove-in-groove protrusion and the recess cooperating to form a secondary locking.

[0009] Furthermore, a first gear fixing post and a second gear fixing post are provided between the front housing and the rear housing. The first gear fixing post is equipped with a first fixing post gear; the second gear fixing post is equipped with a second fixing post gear; the output shaft of the drive motor is equipped with an input shaft gear; the input shaft gear drives the first fixing post gear and thus drives the second fixing post gear to rotate.

[0010] Furthermore, the second fixed column gear is provided with a pusher structure on the gear near the front housing. The pusher structure rotates around the mounting shaft and is used to cooperate with the one-way valve.

[0011] Furthermore, both the first gear fixing post and the second gear fixing post are independent columnar parts, with their ends supported in corresponding holes in the rear housing and the front housing, respectively.

[0012] Furthermore, the mounting shaft is fixed to the rear housing and extends outside the front housing. The mounting shaft is used for guidance and as a mounting base for the mating parts.

[0013] Furthermore, the front housing has a protrusion on the side away from the output end. The protrusion is connected to the main body of the front housing by a ramp transition. The ramp transition section has a window structure for the mating parts to mate with the push-pull structure.

[0014] Furthermore, the snap-fit ​​structure is evenly distributed along the four edges of the rear and front housings.

[0015] Furthermore, the rear and front housings are made of engineering plastics.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Both the rear and front housings are integrally molded, and the position of the mounting holes is directly guaranteed by the precision of the molding die. The same mounting hole on the upper and lower housings is simultaneously positioned by the die core during molding, avoiding the problem of hole misalignment caused by separate processing, which helps to ensure the assembly accuracy of the gear shaft and the fixing column. The gear spacer is integrally molded on the rear and front housings, reducing the number of independent parts. The snap-fit ​​structure replaces the fixing threaded column and screw to fix the housing, and the assembly can be completed without tools, simplifying the assembly process. The stop structure improves the positioning accuracy after the housing is closed, ensuring the stability of the housing during use. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present utility model;

[0020] Figure 2This is a schematic diagram of the exploded structure of Embodiment 2 of this utility model;

[0021] Figure 3 This is an exploded top view showing the positional relationship of the gear set in this utility model;

[0022] Figure 4 This is a schematic diagram of the buckle structure of Embodiment 3 of this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Rear housing; 2. Front housing; 21. Window structure; 3. Gear set; 31. First fixed column gear; 32. Second fixed column gear; 33. Input shaft gear; 41. First gear fixing column; 42. Second gear fixing column; 5. Mounting shaft; 6. Drive motor; 7. Snap-fit ​​structure; 71. Snap ring; 8. Stop structure; 9. Slot-in-slot structure; 10. Gear spacer. Detailed Implementation

[0025] This utility model provides a gearbox for a grease injector. The technical solution of this utility model will be described in detail below through specific embodiments.

[0026] Example 1

[0027] This embodiment provides a gearbox for a grease injector, the overall structure of which is as follows: Figure 1 and Figure 3 As shown.

[0028] The gearbox in this embodiment is used in a grease injector, and its housing provides support and housing space for the gear set. The housing needs to ensure the stability of the gear set during transmission, especially when the pusher structure in the gear set pushes the mating part during rotation. The housing needs to withstand the pusher reaction force and maintain the coaxiality of the gear shaft and the housing hole. In this embodiment, the pusher structure is the protrusion in the middle of the gear, which works in conjunction with the mating part mounted on the mounting post. The mating part is connected to a plunger-type check valve. During gear rotation, the pusher structure pushes the mating part, and the mating part lifts the check valve to achieve a quantitative output of grease.

[0029] The gearbox in this embodiment includes a rear housing 1 and a front housing 2. The rear housing 1 is a rectangular plate-shaped housing when viewed from above. The front housing 2 is positioned opposite to the rear housing 1, and the rear housing 1 and the front housing 2 together enclose the space for accommodating the gear set. Both the rear housing 1 and the front housing 2 are made of engineering plastic and are integrally injection molded. Compared with traditional stamping of galvanized steel sheets, the injection molding process ensures that the positions of the mounting holes on the housing are directly guaranteed by the precision of the mold core. The concentricity of the corresponding holes on the upper and lower housings is determined during the mold design stage, eliminating the need for secondary processing and correction after molding. This effectively avoids the problem of hole misalignment caused by springback and warping deformation of the sheet metal during stamping. In this embodiment, the rear housing 1 and the front housing 2 are preferably injection molded using PA66+GF30 (Nylon 66 with 30% glass fiber). This material has good strength, rigidity, and dimensional stability, and can maintain the structural stability of the housing under the conditions of drive motor operation and push-pull structure push-fitting parts, and is not easily deformed during long-term use. In other embodiments, depending on the operating conditions and cost requirements, the housing material may also be selected from engineering plastics such as PBT+GF, ABS, or PC.

[0030] The rear housing 1 and the front housing 2 are fixedly connected around their edges by a snap-fit ​​structure 7. The snap-fit ​​structure 7 is evenly distributed along the edges of both housings to ensure balanced locking force. Specifically, the front housing 2 has a retaining ring 71 on its edge, and the rear housing 1 has a retaining groove on its edge. The retaining ring 71 has a certain elastic deformation capacity; during assembly, it deforms elastically and embeds itself into the retaining groove, achieving locking under the elastic restoring force of the plastic. This snap-fit ​​connection replaces the multiple threaded posts and screws of traditional solutions, reducing the number of parts. Assembly requires no tools; the housings can be closed and fixed simply by manual pressing, significantly improving assembly efficiency. Under motor vibration conditions, the snap-fit ​​structure relies on the elastic deformation of the material to achieve continuous locking, ensuring a stable and reliable housing connection.

[0031] A first gear fixing post 41 and a second gear fixing post 42 are provided between the front housing 2 and the rear housing 1. The first gear fixing post 41 and the second gear fixing post 42 are both independent columnar parts, with their ends supported in corresponding holes in the rear housing 1 and the front housing 2, respectively, without the need for separate assembly of other connecting parts.

[0032] A first fixed-post gear 31 is mounted on the first gear fixing post 41. The first fixed-post gear 31 is rotatably mounted on the first gear fixing post 41 and includes two large gears and two small gears, which are arranged alternately in size. A second fixed-post gear 32 is mounted on the second gear fixing post 42. The second fixed-post gear 32 is rotatably mounted on the second gear fixing post 42 and includes two large gears and one small gear, which are arranged alternately in size. A pushing structure is provided on the gear of the second fixed-post gear 32 near the front housing 2. The pushing structure rotates around the mounting shaft 5 and is used to cooperate with a one-way valve. An input shaft gear 33 is provided on the output shaft of the drive motor 6. The input shaft gear 33 meshes with the first fixed-post gear 31, and the first fixed-post gear 31 meshes with the second fixed-post gear 32, so that the input shaft gear 33 drives the first fixed-post gear 31 and thus drives the second fixed-post gear 32 to rotate.

[0033] A mounting shaft 5 is fixedly mounted on the rear housing 1, extending beyond the front housing 2. The mounting shaft 5 serves as a guide and a mounting base for the mating component. The mating component is mounted on the extension of the mounting shaft 5 and engages with a pusher structure located on the gear of the second fixed column gear 32 near the front housing 2. As the pusher structure rotates around the mounting shaft 5, it pushes the mating component, which connects to a plunger-type check valve to achieve a metered output of grease.

[0034] A drive motor 6 is mounted on the front housing 2. The output shaft of the drive motor 6 passes through the interior of the housing, and an input shaft gear 33 is fixedly mounted on the output shaft. The drive motor 6 can be fixed by screws or by snap-fit. On the side of the front housing 2 away from the output end (the motor is located on the concave side; the protruding part is the portion of the front housing that protrudes when viewed from above), there is an outwardly protruding part. This protruding part is smoothly connected to the main body of the front housing 2 via a ramp transition section. The protruding part is used to accommodate the push-pull structure on the gear of the second fixed column gear 32 near the front housing 2. A window structure 21 is provided on the ramp transition section. The window structure 21 allows the mating parts to mate with the push-pull structure, enabling the mating parts to engage with the push-pull structure in the gear set 3 on the outside of the housing. The size and position of the window structure 21 are adapted to the range of motion of the push-pull structure, ensuring that the mating parts can move smoothly back and forth under the drive of the push-pull structure without interfering with the housing.

[0035] Gear spacers 10 are integrally injection molded onto both the rear housing 1 and the front housing 2. In the original galvanized steel sheet design, the gear spacers were independent parts, requiring individual assembly onto the fixing posts to axially space the gears. In this embodiment, the gear spacers 10 are designed as an integral structure with the housing, and are formed simultaneously during the housing injection molding process, making them part of either the rear housing 1 or the front housing 2. During assembly, after each gear is axially fitted onto the gear fixing post, there is no longer a need to install individual spacer parts. The axial positioning of the gears is directly provided by the gear spacers 10 on the housing, effectively reducing the total number of parts and assembly steps, and improving assembly efficiency.

[0036] The assembly process of this embodiment is as follows: First, the drive motor 6 is fixedly installed on the front housing 2; the mounting shaft 5 is fixed on the rear housing 1; one end of the first gear fixing post 41 and the second gear fixing post 42 are respectively inserted into the corresponding holes of the rear housing 1; each gear of the first fixing post gear 31 is sequentially fitted into the first gear fixing post 41, and each gear of the second fixing post gear 32 is sequentially fitted into the second gear fixing post 42, with the axial spacing between each gear automatically determined by the integrally formed gear spacer 10 on the housing; then, the front housing 2 and the rear housing 1 are pressed together along the edge, so that the retaining ring 71 is embedded in the corresponding retaining groove and locked, thus completing the assembly of the entire gearbox.

[0037] After assembly, the mating parts are installed on the extension of the mounting shaft 5. When the drive motor 6 is running, the output shaft drives the input shaft gear 33 to rotate, and the input shaft gear 33 drives the first fixed column gear 31 to rotate, which in turn drives the second fixed column gear 32 to rotate. The push structure on the gear of the second fixed column gear 32 near the front housing 2 rotates around the mounting shaft 5, pushing the mating parts on the mounting shaft 5 to reciprocate. The mating parts drive the plunger-type check valve to operate, realizing the quantitative grease injection function of the grease injector.

[0038] Example 2

[0039] This embodiment further optimizes the connection accuracy between the front and rear shells based on Embodiment 1. The explosive structure of this embodiment is as follows: Figure 2 As shown.

[0040] Specifically, a stop structure 8 is provided at the connection between the rear housing 1 and the front housing 2. The stop structure 8 includes a male stop located on the edge of the front housing 2 and a female stop located on the edge of the rear housing 1. The male stop is a protruding structure that extends continuously around the edge of the front housing 2, and the female stop is a recessed structure that extends continuously around the edge of the rear housing 1. The cross-sectional shapes of the male stop and the female stop match each other. During assembly, the male stop is embedded in the female stop, and the two form a tight convex-concave fit.

[0041] For this invention, the stop structure 8 provides centering and limiting functions. After the male stop is embedded in the female stop, the rear housing 1 and the front housing 2 are precisely constrained in the horizontal direction, effectively suppressing relative misalignment or deflection, which helps ensure the positional accuracy of the housing after closing and the coaxiality of the two ends of the gear shaft. It can also correct part deformation. During the injection molding process of engineering plastics, the housing parts may experience slight warping deformation during the cooling and shrinkage stage. The concave-convex fit of the stop structure 8 can provide corrective force when the housing closes, constraining the shape of the deformed part to the designed position, further improving assembly accuracy. Finally, it can improve assembly efficiency. During the housing closing process, the male stop first contacts the guide slope of the female stop, guiding the rear housing 1 and the front housing 2 to automatically align, making the subsequent snap-fit ​​structure 7 more smooth, playing a pre-positioning and guiding role.

[0042] During long-term operation of the gearbox, the stop structure 8 also serves to distribute stress and protect the snap-fit ​​mechanism. After the reaction force generated by the pushing structure pushing the mating parts is transmitted to the housing, the stop structure 8, through the rigid horizontal contact between the male and female stops, bears most of the positioning force between the housings. This allows the snap-fit ​​structure 7 to only bear the locking force in the closing direction of the housings, without having to bear additional horizontal shearing or displacement forces. This division of force reduces the fatigue burden on the snap ring 71 under long-term vibration conditions, improves the long-term reliability of the overall connection, and ensures the stability of the housing during use.

[0043] The other structures and assembly methods in this embodiment are the same as in Embodiment 1, and will not be described again here.

[0044] Example 3

[0045] This embodiment further adds a groove-in-groove structure 9 to the snap-fit ​​structure 7 based on Embodiment 1 or Embodiment 2 to enhance the locking reliability of the snap-fit ​​connection under vibration. The snap-fit ​​structure of this embodiment is as follows: Figure 4 As shown.

[0046] Specifically, the retaining ring 71 has a groove-within-a-groove protrusion, and the retaining groove has a corresponding recess. The groove-within-a-groove protrusion is a slightly raised structure from the fastening surface of the retaining ring 71, and the recess is a structure that is recessed into the material on the inner wall surface of the retaining groove. When the retaining ring 71 is fastened into the retaining groove, the groove-within-a-groove protrusion is precisely embedded in the recess, increasing the mechanical interlocking force between the protrusion and the recess on top of the original friction between the retaining ring 71 and the retaining groove, thus forming a secondary locking effect.

[0047] The function of the slot-within-slot structure 9 is as follows: Under the condition that the drive motor 6 operates continuously and generates continuous vibration, a simple snap-fit ​​relying on the elastic restoring force of the plastic for locking may be at risk of slight loosening under high-frequency vibration; while the mechanical interlocking of the protrusions and recesses in the slot-within-slot provides additional locking resistance. Even if the retaining ring 71 undergoes slight elastic deformation during vibration, the interlocking relationship between the protrusions and recesses in the slot-within-slot still prevents the retaining ring 71 from coming out of the slot. Combined with the damping characteristics of the engineering plastic material itself, the vibration energy is partially attenuated when it is transmitted to the snap-fit ​​connection. The secondary locking of the slot-within-slot structure 9 further improves the vibration resistance and anti-loosening performance, ensuring the long-term stability of the shell connection.

[0048] The other structures and assembly methods in this embodiment are the same as in Embodiment 2, and will not be described again here.

[0049] Regarding the connection methods of the components in each embodiment, it should be noted that, in addition to the connection methods explicitly described, the connections between components can be fixed or detachable. Fixed connections include, but are not limited to: integral molding, welding, bonding, sewing, riveting, and thermoforming. Detachable connections include, but are not limited to: snap-fit ​​connections, magnetic connections, screw connections, Velcro fastening, snap-fit ​​connections, and plug-in connections. The specific connection method can be adapted to actual production conditions and usage requirements.

Claims

1. A gearbox for a grease injector, characterized in that, The device is provided with a rear housing (1) and a front housing (2). The rear housing (1) and the front housing (2) are fixedly connected by a snap-fit ​​structure (7) to form a receiving space. A stop structure (8) is provided at the connection between the rear housing (1) and the front housing (2). A gear set (3) is provided in the receiving space. An installation shaft (5) is provided on the rear housing (1). A drive motor (6) is provided on the front housing (2). The output shaft of the drive motor (6) extends into the receiving space and cooperates with the gear set (3). The rear housing (1) and the front housing (2) are both integrally formed and are integrally formed with a gear spacer (10).

2. The gearbox for a grease injector according to claim 1, characterized in that, The front housing (2) has a retaining ring (71) on its edge, and the rear housing (1) has a retaining groove on its edge. The retaining ring (71) and the retaining groove cooperate to achieve fastening and locking.

3. The gearbox for a grease injector according to claim 2, characterized in that, The retaining ring (71) has a groove-in-groove protrusion, and the retaining groove has a recess corresponding to the groove-in-groove protrusion. The groove-in-groove protrusion and the recess cooperate with each other to form a secondary locking.

4. A gearbox for a grease injector according to any one of claims 1 to 3, characterized in that, A first gear fixing post (41) and a second gear fixing post (42) are provided between the front housing (2) and the rear housing (1). The first gear fixing post (41) is provided with a first fixing post gear (31); the second gear fixing post (42) is provided with a second fixing post gear (32); the output shaft of the drive motor (6) is provided with an input shaft gear (33); the input shaft gear (33) drives the first fixing post gear (31) and then drives the second fixing post gear (32) to rotate.

5. A gearbox for a grease injector according to claim 4, characterized in that, The second fixed column gear (32) has a push structure on the gear near the front housing (2). The push structure rotates around the mounting shaft (5) and is used to cooperate with the one-way valve.

6. A gearbox for a grease injector according to claim 4, characterized in that, The first gear fixing post (41) and the second gear fixing post (42) are both independent columnar parts, with their ends supported in the corresponding holes of the rear housing (1) and the front housing (2), respectively.

7. A gearbox for a grease injector according to any one of claims 1 to 3, characterized in that, The mounting shaft (5) is fixed to the rear housing (1) and extends to the outside of the front housing (2). The mounting shaft (5) is used for guidance and as the mounting base for the mating parts.

8. A gearbox for a grease injector according to any one of claims 1 to 3, characterized in that, The front housing (2) has a protrusion on the side away from the output end. The protrusion is connected to the main body of the front housing (2) by a ramp transition. A window structure (21) is provided on the ramp transition section. The window structure (21) is used to allow the mating parts to mate with the push structure.

9. A gearbox for a grease injector according to any one of claims 1 to 3, characterized in that, The snap-fit ​​structure (7) is evenly distributed along the four edges of the rear housing (1) and the front housing (2).

10. A gearbox for a grease injector according to any one of claims 1 to 3, characterized in that, The rear shell (1) and the front shell (2) are made of engineering plastic.

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