Reciprocating micro water pump

Abstract

The application relates to a reciprocating micro water pump, comprising a pump shell, a pumping component arranged in the pump shell and used for pumping fluid, a driving motor comprising an output gear for outputting power, a transmission assembly comprising an end face gear meshing with the output gear, a cam fixedly connected to the end face gear and a transmission rod, the transmission rod comprising a sleeve part defining a transmission cavity and a rod part for transmission connection of the pumping component, and the cam being located in the transmission cavity; wherein the inner contour surface of the transmission cavity is provided with a stroke arc surface, the stroke arc surface has a starting point and an ending point, when the transmission rod is located at the lower dead point, the stroke arc surface is located below the outermost movement track of the cam and the distance between the stroke arc surface and the cam gradually increases in the axial direction, the minimum distance and the maximum distance are respectively located at the starting point and the ending point, and the corresponding central angle of the stroke arc surface is less than 180 DEG; when the reciprocating micro water pump is in the stroke stage, the cam contacts the stroke arc surface and pushes the transmission rod.

Description

Technical Field

[0001] This application relates to the field of microfluidic device technology, and in particular to a reciprocating micro water pump. Background Technology

[0002] A common type of reciprocating micro water pump has a pumping component for pumping fluid, a transmission assembly that drives the pumping component, and a drive motor that provides power to the transmission assembly. When the reciprocating micro water pump is working, the transmission assembly periodically drives the pumping component to move or deform, thereby periodically alternating negative and positive pressures in the pump chamber to draw in and pump out fluid.

[0003] These reciprocating miniature water pumps are widely used in oral irrigators, and the pump's outlet pressure determines the cleaning ability of the corresponding oral irrigator. Current technology often increases the pump's outlet pressure by replacing the motor with one that operates at a higher speed, but this approach comes with many disadvantages, including increased cost, increased motor heat generation, and difficulty in miniaturization. Utility Model Content

[0004] The purpose of this invention is to provide a structure that can increase the outlet pressure of a pump without replacing the motor.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a reciprocating micro water pump, comprising: a pump casing; a pumping component disposed within the pump casing and used for pumping fluid; a drive motor, including an output gear for external power output; a transmission assembly, including an end face gear meshing with the output gear, a cam fixedly connected to the end face gear, and a transmission rod, wherein the transmission rod includes a sleeve portion defining a transmission cavity and a rod portion for transmission connection to the pumping component, and the cam is located within the transmission cavity; wherein, the inner contour surface of the transmission cavity has a stroke arc surface, the stroke arc surface has a starting point and an ending point, and when the transmission rod is at the bottom dead center, the stroke arc surface is located below the outermost movement trajectory of the cam and the axial distance between the two gradually increases, with the minimum and maximum distances located at the starting point and the ending point, respectively, and the central angle corresponding to the stroke arc surface is less than 180°; when the reciprocating micro water pump is in the stroke stage, the cam contacts the stroke arc surface and pushes the transmission rod.

[0006] In the above technical solution, preferably, the central angle corresponding to the stroke arc surface is in the range of 60°-120°.

[0007] In the above technical solution, preferably, the cam has an outwardly protruding contact arc surface, and when the reciprocating micro water pump is working, the contact arc surface keeps in contact with the inner contour surface of the transmission cavity.

[0008] In the above technical solution, preferably, the inner contour surface of the transmission cavity also has an upper stop arc surface. When the transmission rod is located at the top dead center, the radius of curvature of the upper stop arc surface is equal to the distance from the upper stop arc surface to the rotation center of the cam, and the cam contacts the upper stop arc surface. Further preferably, the central angle corresponding to the upper stop arc surface is in the range of 30°-60°.

[0009] In the above technical solution, preferably, the inner contour surface of the transmission cavity also has a lower stop arc surface. When the transmission rod is located at the lower stop point, the radius of curvature of the lower stop arc surface is the distance from the lower stop arc surface to the rotation center of the cam, and the cam contacts the lower stop arc surface. Further preferably, the central angle corresponding to the lower stop arc surface is in the range of 60°-90°.

[0010] In the above technical solution, preferably, the transmission assembly further includes a gear shaft, which is fixed inside the pump housing and extends radially, and the end face gear is rotatably supported on the gear shaft. More preferably, the sleeve portion has an axially extending limiting through hole, and the gear shaft and the limiting through hole form a shaft-hole fit to limit the movement direction of the transmission rod axially.

[0011] Compared to existing technologies, the reciprocating micro water pump provided by this invention features a cam that contacts the stroke arc surface and pushes the transmission rod during the stroke phase. The transmission rod then drives the pumping components to compress the fluid. Because the stroke arc surface of this invention is less than 180°, the time the reciprocating micro water pump spends in the stroke phase can be reduced without replacing the drive motor, thus avoiding or reducing the decrease in outlet pressure caused by premature opening of the outlet valve. Attached Figure Description

[0012] Figure 1 A perspective view of the reciprocating micro water pump provided by this utility model;

[0013] Figure 2 for Figure 1 Cross-section of the reciprocating micro water pump shown Figure 1 ;

[0014] Figure 3 for Figure 1 Cross-section of the reciprocating micro water pump shown Figure 2 ;

[0015] Figure 4 for Figure 3 A magnified view of a portion at point A shown;

[0016] Figure 5 for Figure 3 A partial enlarged view of the transmission assembly shown;

[0017] Figure 6 for Figure 5 A schematic diagram comparing the inner contour of the transmission cavity of the transmission assembly with the outermost motion trajectory of the cam.

[0018] Figure 7 for Figure 1 Explosion of the pumping assembly of the reciprocating micro water pump shown Figure 1 ;

[0019] Figure 8 for Figure 1 Explosion of the pumping assembly of the reciprocating micro water pump shown Figure 2 ;

[0020] Figure 9 for Figure 1 An exploded view of the transmission assembly of the reciprocating micro water pump shown.

[0021] Figure 10 The diagram shows the outlet pressure test of a reciprocating micro water pump using a transmission component in the prior art.

[0022] Figure 11 for Figure 1 The diagram shows the outlet pressure test of a reciprocating micro water pump.

[0023] Marked in the image:

[0024] 100. Reciprocating miniature water pump;

[0025] 1. Pump casing; 11. First casing; 111. Mating part; 112. Fixing part;

[0026] 12. Second housing; 13. Water inlet;

[0027] 21. Water inlet / outlet base; 211. Base plate; 212. Bottom enclosure; 213. Water inlet pipe; 2131. First water inlet; 214. Water outlet pipe; 2141. First water outlet; 215. Water inlet boss; 216. Water outlet boss; 217. First ear;

[0028] 22. Valve seat; 221. Top enclosure; 222. Second inlet; 223. Second outlet; 224. Inlet enclosure; 225. Outlet enclosure; 226. Outer cylinder; 227. Sealing groove; 228. Cantilever; 229. Second ear; 2210. Protruding lip;

[0029] 23. Base; 231. Inner cylinder; 2311. Step; 2312. Base surface; 232. Raised edge;

[0030] 24. Diaphragm component; 241. Plunger part; 242. Deformable part; 243. Mounting part; 2431. Base; 2432. Protrusion; 244. Transmission part;

[0031] 25. Pump chamber; 26. Sealing ring; 27. Valve;

[0032] 31. End face gear; 311. Gear body; 312. Positioning shaft; 313. Positioning rib;

[0033] 32. Gear shaft;

[0034] 33. Cam; 331. Mating hole; 332. Contact part;

[0035] 34. Transmission rod; 341. Transmission cavity; 342. Sleeve section; 343. Rod section; 344. Support surface; 345. Limiting through hole;

[0036] 4. Drive motor; 41. Motor shaft; 42. Output gear;

[0037] Y, axis; S, clearance; C1, stroke arc surface; C2, return arc surface; C3, upper stop arc surface; C4, lower stop arc surface; a, starting point; b, ending point. Detailed Implementation

[0038] To explain in detail the technical content, structural features, achieved objectives and effects of this application, the technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings.

[0039] In this application, spatial relative terms such as “below,” “under,” “below,” “down,” “above,” “above,” “higher,” and “side” (e.g., as in a “sidewall”) are used to describe the relationship between one element and another element as shown in the accompanying drawings. Spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture other than those depicted in the drawings. For example, if the device in the drawings is flipped, an element described as “below” or “under” another element or feature would then be positioned “above” said other element or feature. Thus, the exemplary term “below” can include both above and below orientations. Furthermore, the device may be otherwise positioned (e.g., rotated 90 degrees or in other orientations), thus interpreting the spatial relative descriptive terms used herein accordingly.

[0040] In this application, the term "axial" refers to the direction in which the axis of the reciprocating micro water pump extends; the term "radial" refers to the direction perpendicular to the axis of the reciprocating micro water pump. For ease of explanation, this application defines the pump's height direction as axial, with the inlet and outlet water seats located above the drive rod.

[0041] In this application, the uppermost and lowermost points in the motion trajectory of the transmission rod are defined as "top dead center" and "bottom dead center", respectively. The process of the transmission rod moving from the bottom dead center to the top dead center is defined as the stroke, and the process of the transmission rod moving from the top dead center to the bottom dead center is defined as the return stroke.

[0042] In this application, the view is taken from a cross-sectional perspective along the axial direction and perpendicular to the centerline of the gear shaft (i.e. Figure 3 (From a perspective) When the transmission rod is at the bottom dead center, the two endpoints (such as the starting and ending points of the stroke arc) of a certain arc surface (such as the inner contour surface of the transmission cavity) are connected to the rotation center of the cam respectively. The included angle of the two lines formed is defined as the central angle corresponding to the arc surface.

[0043] See Figure 1 This application provides a reciprocating micro water pump 100 for use in a dental flosser, designed to increase the output pressure of a fluid. Specifically, the reciprocating micro water pump 100 is positioned along an axis Y (see...). Figure 2 , 3 It extends and includes a pump housing 1, a pumping assembly for pumping fluid, a transmission assembly for driving the pumping assembly, and a drive motor 4 for providing power.

[0044] Combination Figure 2-3 The drive motor 4 includes a motor housing (not shown in the figure), a motor shaft 41 extending axially outward relative to the motor housing, and an output gear 42 fixedly mounted on the motor shaft 41. The drive motor 4 outputs power to the outside through the output gear 42. The pump housing 1 includes a first housing 11, a second housing 12 detachably mounted on the first housing 11, and a water inlet 13.

[0045] The first housing 11 includes an axially extending mating portion 111 and a radially extending fixing portion 112. The fixing portion 112 is located at the bottom of the first housing 11 and has a transmission port (not shown in the figure). The second housing 12 is detachably mounted on the mating portion 111 of the first housing 11 and is disposed above the fixing portion 112. The drive motor 4 is fixedly connected to the lower side of the fixing portion 112 of the first housing 11, and its motor shaft 41 and output gear 42 both pass into the interior of the pump housing 1 through the transmission port of the fixing portion 112.

[0046] Compared to the traditional installation method where the drive motor is jointly limited or clamped by the first and second housings, the drive motor 4 provided in this application is installed on the first housing 11. This reduces the motor shaft misalignment caused by the fit error between the first and second housings in the traditional installation method, and allows the output gear 42 to achieve a good fit with the end face gear (see below).

[0047] See Figure 7-8The pumping assembly of the reciprocating micro water pump 100 includes an inlet / outlet base 21, a valve seat 22 mounted under the inlet / outlet base 21, a base 23 mounted under the valve seat 22, a pumping component sandwiched between the valve seat 22 and the base 23, and a plurality of valves 27 sandwiched between the valve seat 22 and the inlet / outlet base 21. In this embodiment, the pumping component is a diaphragm 24, and the aforementioned valves 27 are used to define the flow direction of the fluid within the reciprocating micro water pump 100.

[0048] The inlet / outlet base 21 includes a base plate 211 located at the bottom and extending radially, a bottom enclosure 212 formed by the outer edge of the base plate 211 extending downward, an inlet pipe 213 fixedly connected to the upper side of the base plate 211, and an outlet pipe 214 also fixedly connected to the upper side of the base plate 211. When the inlet / outlet base 21 is installed inside the pump housing 1, the inlet pipe 213 is in fluid communication with the inlet nozzle 13, and the top of the outlet pipe 214 is exposed to the outside relative to the pump housing 1 to form an outlet nozzle.

[0049] The bottom enclosure 212 and the base plate 211 of the inlet and outlet water seat 21 together form a mating cavity with a lower opening (not marked in the figure). The inlet pipe 213 and the outlet pipe 214 respectively form a first inlet 2131 and a first outlet 2141 that protrude from the mating cavity (i.e., protrude from the side surface of the base plate 211 near the valve seat 22).

[0050] The valve seat 22 includes a top enclosure 221 formed at the top and extending circumferentially, a second inlet 222 opened at the top and fluidly communicating with the pump chamber 25 (see below), and a second outlet 223 also opened at the top and fluidly communicating with the pump chamber 25. When the valve seat 22 is installed under the inlet / outlet seat 21, the top enclosure 221 of the valve seat 22 is inserted into the mating cavity of the inlet / outlet seat 21 and closely abuts the bottom enclosure 212 of the inlet seat 21 to form a seal; the first inlet 2131 is connected to the second inlet 222, and the inlet nozzle 13, the inlet pipe 213, and the second inlet 222 are fluidly connected in sequence to form an inlet path for fluid to enter the pump chamber 25; the second outlet 223 is connected to the first outlet 2141, and the second outlet 223 is fluidly connected to the outlet pipe 214 to form an outlet path for fluid in the pump chamber 25 to leave the reciprocating micro water pump 100. Understandably, in other embodiments, the bottom enclosure of the inlet / outlet water seat may be inserted into the interior of the top enclosure of the valve seat and pressed against the top enclosure to form a seal.

[0051] Furthermore, the pumping assembly also includes a sealing ring 26. The inlet / outlet seat 21 also includes an inlet boss 215 and an outlet boss 216 formed at the bottom and exposed to the outside. A first inlet 2131 and a first outlet 2141 are formed on the inlet boss 215 and the outlet boss 216, respectively. The valve seat 22 is provided with an inlet enclosure 224 and an outlet enclosure 225 located within the top enclosure 221. A second inlet 222 and a second outlet 223 are located inside the inlet enclosure 224 and the outlet enclosure 225, respectively. The inlet enclosure 224, the outlet enclosure 225, and the top enclosure 221 together form a sealing groove 227 that adapts to the sealing ring 26.

[0052] When the valve seat 22 is installed on the underside of the inlet / outlet seat 21, the inlet boss 215 and the outlet boss 216 are respectively inserted into the interior of the inlet enclosure 224 and the outlet enclosure 225. The sealing ring 26 is inserted into the sealing groove 227 and is held by the inlet / outlet seat 21 and the valve seat 22, thereby sealing the inlet and outlet paths. It can be understood that in other embodiments, the aforementioned inlet boss, outlet boss, and sealing ring may also be provided on the top of the valve seat, while the inlet enclosure and outlet enclosure may be adaptively provided on the bottom of the inlet / outlet seat.

[0053] The diaphragm member 24 has a plunger portion 241 located at the center, a mounting portion 243 located on the outer periphery, a deformable portion 242 located between the plunger portion 241 and the mounting portion 243, and a transmission portion 244 also located at the center. The plunger portion 241 and the transmission portion 244 are configured to face towards and away from the inlet / outlet water seat 21, respectively. The transmission portion 244 is connected to a transmission assembly, and the mounting portion 243 is clamped between the base 23 and the valve seat 22 to fix the diaphragm member 24 inside.

[0054] The diaphragm 24 is installed inside the valve seat 22, and the diaphragm 24 and the valve seat 22 together form a pump chamber 25. Understandably, when the diaphragm 24 is pushed upward by the transmission assembly (i.e., when the reciprocating micro water pump 100 is in the stroke phase), the volume of the pump chamber 25 decreases and positive pressure is formed; when the diaphragm 24 is pulled downward by the transmission assembly (i.e., when the reciprocating micro water pump 100 is in the return phase), the volume of the pump chamber 25 increases and negative pressure is formed.

[0055] The valve seat 22 also includes a downwardly extending outer cylinder 226 with a bottom opening. The base 23 has an inner cylinder 231 that can extend into the outer cylinder 226 and a protruding edge 232 located at the bottom and projecting radially outward relative to the cylinder wall 231. When the base 23 is installed in the valve seat 22, the inner cylinder 231 extends into the interior of the outer cylinder 226, and the protruding edge 232 of the base 23 contacts the bottom of the outer cylinder 226.

[0056] Combination Figure 4The top of the inner cylinder 231 has a stepped structure, which has an inner step 2311 and an outer base surface 2312, with the step 2311 protruding upward relative to the base surface 2312. The mounting portion 243 of the diaphragm member 24 has a radially extending base 2431 and a protrusion 2432 extending axially downward from the base 2431. Both the protrusion 2432 and the base 2431 are annular, and the base 2431 protrudes radially outward relative to the protrusion 2432.

[0057] When the diaphragm 24 is clamped by the base 23 and the valve seat 22, the protrusion 2432 on the diaphragm 24 simultaneously contacts the base surface 2312 and the step 2311 of the inner cylinder 231. The step 2311 radially prevents the protrusion 2432 from moving inward. The inner wall of the outer cylinder 226 contacts the radial edge of the base 2432 and radially prevents the base 2432 from moving outward. A gap S is formed between the mounting portion 243 of the diaphragm 24 and the inner wall of the outer cylinder 226, which provides space for the mounting portion 243 to deform freely.

[0058] When the diaphragm 24 is clamped between the base 23 and the valve seat 22, the mounting portion 243 of the diaphragm 24 will undergo a certain adaptive deformation due to pressure. If the deformation of the mounting portion 243 is suppressed at this time, it will be difficult for the valve seat 22, the mounting portion 24, and the base 23 to fit together completely, resulting in a poor seal. Therefore, in the technical solution provided by this utility model, the aforementioned gap S provides space for the mounting portion 243 to deform freely.

[0059] Furthermore, the deformable portion 242 includes an inner perimeter portion near the plunger portion 241 and a peripheral portion near the mounting portion 243. A plurality of cantilever arms 228 extending downwards and spaced apart from its inner wall are formed on the valve seat 22. When the diaphragm member 24 is clamped between the base 23 and the valve seat 22, the plurality of cantilever arms 228 on the valve seat 22 contact the peripheral portion of the deformable portion 242 and prevent it from moving inwards radially. A slot (not shown in the figure) adjacent to the deformable portion 242 is formed on the mounting portion 243, and the step 2311 of the inner cylinder 231 is inserted into the aforementioned mounting slot and contacts the peripheral portion of the deformable portion 242 to prevent the peripheral portion of the deformable portion 242 from moving outwards radially. Thus, the peripheral portion of the deformable portion 242 is clamped between the valve seat 22 and the base 23, further reducing the possibility of relative movement between the valve seat 22, the base 23, and the diaphragm member 24.

[0060] Furthermore, considering that the aforementioned fixing method would result in a large bending angle of the outer portion of the deformable part 242 during the stroke phase of the reciprocating micro water pump 100, which could potentially lead to cracking after repeated bending over a long period, causing machine failure, the present technical solution provides a clearance fit between the various cantilever 228s, i.e., a gap is formed between two adjacent cantilever 228s. This gap provides the cantilever 228 with greater deformation performance. During the stroke phase of the reciprocating micro water pump 100, the cantilever 228 can undergo a certain deformation under the tension of the deformable part 242, reducing the bending angle of the deformable part 242 and increasing its service life.

[0061] Furthermore, the surface of the inlet / outlet water seat 21 that contacts the diaphragm 24 is also formed with a plurality of protruding lips 2210 that protrude toward the diaphragm 24. The protruding lips 2210 are annular and are used to further reinforce the diaphragm 24.

[0062] Back Figure 2-3 The first housing 11 and the second housing 12 together form an inner cavity (not shown in the figure) suitable for accommodating the pump assembly. This inner cavity has an opening (not shown in the figure) located at the top of the pump housing 1 and exposed to the outside. When the pump assembly is installed in the pump housing 1, the outlet pipe 214 on the inlet / outlet seat 21 is exposed to the outside through the aforementioned opening. The top wall of the inner cavity contacts and can apply pressure to the upper surface of the base plate 211, and the bottom wall of the inner cavity contacts and can apply pressure to the lower surface of the base 23. Thus, the inlet / outlet seat 21, valve seat 22, diaphragm 24, and base 23 are together fixed in the inner cavity of the pump housing 1.

[0063] Furthermore, considering that the inlet / outlet water seat 21 and valve seat 22 are subjected to significant fluid forces and vibrations during operation of the reciprocating micro water pump 100, further fixation is required. Therefore, the inlet / outlet water seat 21 provided in this embodiment has a pair of radially outwardly extending first ears 217, and the valve seat 22 also has a pair of radially outwardly extending second ears 229, with a pair of radially outwardly extending ear cavities (not shown in the figure) formed on its inner cavity. When the pump assembly is installed inside the pump housing 1, the first ears 217 and the corresponding second ears 229 are attached and inserted into the corresponding ear cavities. The top and bottom walls of the ear cavities contact the upper surface of the first ears 217 and the lower surface of the second ears 229, respectively, and apply pressure to them, thereby fixing the inlet / outlet water seat 21 and valve seat 22.

[0064] Continue reading Figure 2-3 The transmission assembly of the reciprocating micro water pump 100 includes an end face gear 31 that meshes with the output gear 42, a gear shaft 32 for supporting the end face gear 31, a cam 33 fixedly mounted on the end face gear 31, and a transmission rod 34 that can be pushed by the cam 33. The two ends of the gear shaft 32 can be fixed to the first housing 11 and the second housing 12 on the pump housing 1, respectively, and the axis of the gear shaft 32 is defined radially.

[0065] Combination Figure 5 and Figure 9 The end gear 31 is rotatably mounted on the gear shaft 32. The end gear 31 has a shaft hole (not shown in the figure) through which the gear shaft passes, and includes a gear body 311 with toothed surfaces and a positioning shaft 312 that protrudes radially outward from the center of the gear body 311. The positioning shaft 312 has several outwardly protruding positioning ribs 313. The cam 33 has a mating hole 331 that adapts to the positioning shaft 312 and the positioning ribs 313, and an outwardly protruding contact portion 332. The outer surface of the contact portion 332 is arc-shaped and has the farthest distance from the outer edge of the cam 33 to the center of the motor shaft 42.

[0066] The transmission rod 34 includes a sleeve portion 342 defining a transmission cavity 341 and a rod portion 343 fixedly connected to the sleeve portion 342. In this embodiment, the transmission portion 244 of the diaphragm member 24 is an elastic snap, and a slot (not shown in the figure) adapted to the elastic snap is formed on the rod portion 343 of the transmission rod 34. The aforementioned elastic snap engages with the slot to form a transmission connection between the transmission rod 34 and the diaphragm member 24. It is understood that in other embodiments, the transmission rod can also be inserted into the interior of the diaphragm member to form a transmission engagement.

[0067] Furthermore, in this embodiment, a ring-shaped support surface 344 is formed on the top of the transmission rod 34. When the transmission rod 34 is in the stroke stage, the support surface 344 can contact the deformable part 242 of the diaphragm member 24 and apply pressure to the deformable part 242 to prevent the deformable part 242 from excessively deforming and expanding under fluid pressure, which would cause the actual volume of the pump chamber 25 to increase and the internal fluid pressure to decrease.

[0068] The transmission cavity 341 is configured to accommodate the cam 33. During the stroke phase of the reciprocating micro water pump 100, the contact portion 332 of the cam 33 contacts the inner wall of the transmission cavity and applies upward pressure to the sleeve portion 342 to push the plunger portion 241 of the diaphragm member 24 upward. During the return phase of the reciprocating micro water pump 100, the high-pressure fluid remaining in the pump cavity first applies downward pressure to the transmission rod 34, causing the transmission cavity 341 to remain in contact with the contact portion of the cam 33. Then, the contact portion 332 of the cam 33 applies downward pressure to the transmission cavity 341 and drives the transmission rod 34 to move downward.

[0069] The sleeve portion 342 of the transmission rod 34 is also provided with an axially extending limiting through hole 345, which is adjacent to the transmission cavity 341 on the transmission rod 34. The gear shaft 32 passes through the transmission cavity 341 and forms a shaft hole fit with the transmission cavity 341. Thus, the direction of movement of the transmission rod 34 can be limited axially by using the gear shaft 32 fixed inside the pump cover 1.

[0070] Furthermore, the transmission assembly is configured such that, during operation of the reciprocating micro water pump 100, the contact portion 332 of the cam 33 remains in contact with the inner contour surface of the transmission cavity 341. This avoids impacts caused by the cam 33 disengaging from and re-engaging with the transmission cavity 341 (especially during the switching between the stroke and return phases), thus reducing the overall vibration and noise level of the pump.

[0071] like Figure 6 As shown, taking the case where the transmission rod 34 is at the bottom dead center as an example. Circle H in the figure represents the outermost motion trajectory formed by the rotation of the cam 33 (in this embodiment, the motion trajectory of the contact portion 332). This motion trajectory is centered on the rotation center of the gear shaft 32 (in this embodiment, the center of rotation of the gear shaft 32). Figure 6 The circle with the center line of the gear shaft 32 (from the perspective of the rotation) as the center and the distance from the contact part 332 to the center of rotation as the radius is a circle. Part of the inner contour surface of the transmission cavity 341 is located below the circle H. The axial distance h between the two is the approximate height to which the transmission rod 34 is pushed when the cam 33 rotates to that point (there may be a slight deviation due to the change of the contact point on the cam 33).

[0072] The inner contour surface of the transmission cavity 341 has a stroke arc surface C1 and a return arc surface C2. The stroke arc surface C1 has a starting point a and an ending point b. The stroke arc surface C1 is located below the outermost motion trajectory of the cam 33 at the corresponding point of circle H, and the axial distance between the stroke arc surface C1 and its motion trajectory continuously increases, with the minimum and maximum distances formed at the starting point a and the ending point b, respectively. When the reciprocating micro water pump 100 is in the stroke phase, the contact point between the cam 33 and the stroke arc surface C1 moves from the starting point a to the ending point b. The stroke arc surface C1 is configured such that its corresponding included angle is less than 180°.

[0073] Theoretically, the outlet pressure of the reciprocating micro water pump 100 depends on its compression ratio. However, in reality, during the stroke phase of the reciprocating micro water pump 100, the pressure inside the pump chamber 25 continuously increases. When the pressure exceeds the opening pressure of the outlet valve, the outlet valve opens. At this time, the plunger section 241 often has not reached the top dead center, and some of the fluid inside the pump chamber 25 begins to leave the pump chamber 25, thus reducing the pressure in the pump chamber 25 to some extent.

[0074] Understandably, the longer the reciprocating diaphragm pump 100 is in its stroke, the longer the outlet valve remains open before the plunger section 241 reaches top dead center, and the closer the fluid's outlet pressure is to the outlet valve's opening pressure. Therefore, by reducing the stroke duration of the reciprocating micro pump 100, the fluid's outlet pressure can be increased to some extent. This application modifies the cam structure of a conventional reciprocating diaphragm pump and configures a transmission rod 34 with a specially shaped transmission cavity 341, reducing the stroke time without using a higher-speed motor and achieving a higher fluid outlet pressure.

[0075] Furthermore, the central angle corresponding to the stroke arc C1 is preferably within the range of 60°-120°. If the corresponding central angle is too large, it means that the reciprocating micro water pump 100 spends too long in the stroke phase, and its pressurization effect is not obvious. If the corresponding central angle is too small, it is necessary to increase the output torque of the motor, which increases the product cost and is not conducive to miniaturization.

[0076] See Figure 9 and Figure 10 , Figure 10 This is a test diagram of the internal pressure of the reciprocating micro water pump 100 provided in this embodiment under an operating voltage of 3.6V. Figure 9 This is a test diagram of the pump chamber pressure of a reciprocating micro water pump using a traditional transmission structure (except for the transmission component, the other structures are the same as in this embodiment; the traditional transmission structure can be found in utility model patent publication number CN210582710U) under a 3.6V operating voltage. The highest value of the pump chamber pressure is the pump's outlet pressure. From... Figure 9-10 As can be seen, the reciprocating micro water pump 100 provided in this embodiment can reach about 1000 kPa, which is 25% higher than that of the comparative product. Correspondingly, the fluid pressurization time in the reciprocating micro water pump 100 provided in this embodiment is shorter than that of the comparative product, because the stroke time of this embodiment is shorter.

[0077] Furthermore, in the technical solution of this application, the transmission cavity 341 also has an upper stop arc surface C3 that allows the transmission rod 34 to briefly stop at the top dead center, providing the diaphragm 24 with time to recover. This reduces stress fatigue caused by repeated pushing and pulling of the diaphragm 24 at the top dead center, thus improving its service life. Understandably, to allow the transmission 34 to briefly stop at the top dead center, the radius of curvature of the upper stop arc surface C3 is equal to the distance from the upper stop arc surface C3 to the rotation center of the cam 33 when the transmission rod 34 is at the top dead center, i.e., equal to the radius of circle H in the figure. Further, the central angle corresponding to the upper stop arc surface C3 is in the range of 30°-60°.

[0078] Similarly, in the technical solution itself, the transmission cavity 341 also has a lower stop arc surface C4 that allows the transmission rod 34 to briefly stop at the lower dead center, providing the diaphragm 24 with time to recover. This reduces stress fatigue caused by repeated pushing and pulling of the diaphragm 24 at the lower dead center, thus improving its service life. Furthermore, the lower stop arc surface C4 can increase the fluid volume entering the pump cavity 25, improving the utilization rate of the pump cavity 25 and the pump's outlet flow rate. Understandably, to allow the transmission rod 34 to briefly stop at the upper dead center, the radius of curvature of the upper stop arc surface C4 is equal to the distance from the lower stop arc surface C4 to the rotation center of the cam 33 when the transmission rod 34 is at the lower dead center, i.e., equal to the radius of circle H in the figure. Further, the central angle corresponding to the lower stop arc surface C4 is in the range of 60°-90°.

[0079] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be construed as limiting the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit of this application should be included within the scope of protection of this application.

Claims

1. A reciprocating micro water pump, characterized in that, include: Pump casing; A pumping component, disposed within the pump casing, is used to pump fluid; Drive motor, including output gears that output power to the outside; The transmission assembly includes an end face gear that meshes with the output gear, a cam fixedly connected to the end face gear, and a transmission rod. The transmission rod includes a sleeve portion defining a transmission cavity and a rod portion that is transmissionally connected to the pumping component. The cam is located inside the transmission cavity. The transmission cavity has a stroke arc surface on its inner contour surface. The stroke arc surface has a starting point and an ending point. When the transmission rod is at the bottom dead center, the stroke arc surface is located below the outermost motion trajectory of the cam, and the axial distance between the two gradually increases. The minimum distance and the maximum distance are located at the starting point and the ending point, respectively. The central angle corresponding to the stroke arc surface is less than 180°. When the reciprocating micro water pump is in the stroke stage, the cam contacts the stroke arc surface and pushes the transmission rod.

2. The reciprocating micro water pump according to claim 1, characterized in that, The central angle corresponding to the stroke arc surface is in the range of 60°-120°.

3. The reciprocating micro water pump according to claim 1, characterized in that, The cam has an outwardly protruding contact portion, which remains in contact with the inner contour surface of the transmission cavity when the reciprocating micro water pump is working.

4. The reciprocating micro water pump according to claim 1, characterized in that, The inner contour surface of the transmission cavity also has an upper stop arc surface. When the transmission rod is located at the upper stop point, the radius of curvature of the upper stop arc surface is equal to the distance from the upper stop arc surface to the rotation center of the cam, and the cam is in contact with the upper stop arc surface.

5. The reciprocating micro water pump according to claim 4, characterized in that, The central angle corresponding to the upper stop arc surface is in the range of 30°-60°.

6. The reciprocating micro water pump according to claim 1 or 4, characterized in that, The inner contour surface of the transmission cavity also has a lower stop arc surface. When the transmission rod is located at the lower stop point, the radius of curvature of the lower stop arc surface is the distance from the lower stop arc surface to the rotation center of the cam, and the cam is in contact with the lower stop arc surface.

7. The reciprocating micro water pump according to claim 6, characterized in that, The central angle corresponding to the lower stop arc surface is in the range of 60°-90°.

8. The reciprocating micro water pump according to claim 1, characterized in that, The transmission assembly also includes a gear shaft, which is fixed inside the pump housing and extends radially, and the end face gear is rotatably supported on the gear shaft.

9. The reciprocating micro water pump according to claim 8, characterized in that, The sleeve portion is provided with an axially extending limiting through hole, and the gear shaft and the limiting through hole form a shaft hole fit to limit the movement direction of the transmission rod to the axial direction.

Images