Novel piston and oil pump

Abstract

This invention aims to provide a novel piston and oil pump. The novel piston has an axially oriented oil reservoir on one end face. An oil passage hole is radially formed on the outer wall of the end of the piston near the oil reservoir, communicating with the oil reservoir. A flat groove is also formed on the outer wall of the oil passage hole, with the oil passage hole located on the inner bottom wall of the flat groove. A gap is provided between the flat groove and the end face of the piston near the oil reservoir. Thus, the flat groove of the novel piston is cylindrical, effectively supported during centerless grinding, resulting in good stability and improved surface rounding accuracy. Furthermore, because the novel piston has an overall cylindrical structure, the stability of the centerless grinder is effectively improved, allowing for processing using a through-feed centerless grinder, thereby increasing the processing efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of oil pumps, and in particular to a novel piston and oil pump. Background Technology

[0002] The chainsaw oil pump is used to pump oil from the chainsaw chain for lubrication.

[0003] For example, Chinese patent document CN221568812U discloses a high-precision reciprocating oil pump, which includes a pump body and a pump pressure assembly. The pump pressure assembly includes a plunger with an oil storage step. As the plunger rotates within the pump body and periodically slides axially back and forth, the space of the oil storage step within the pump body periodically increases and decreases. During the increasing cycle, negative pressure causes oil to flow into the oil storage step through the oil inlet. During the decreasing cycle, positive pressure causes oil to flow out through the oil outlet, thus realizing the oil pumping action.

[0004] However, existing plunger structures face the following problems during manufacturing: They utilize the space within the pump body where the oil reservoir step slides axially during plunger rotation to generate differential pressure, thus achieving precise oil pumping. Therefore, the oil reservoir step is a key functional component for precise oil pumping control. The plunger needs to be fitted snugly into the pump body, rotating and sliding axially relative to it. Therefore, the oil pumping accuracy is closely related to the plunger's cylindricity. Currently, centerless grinding is used to round the plunger. However, in existing plungers, the portion at the oil reservoir step is essentially suspended. During centerless grinding, the lack of effective support at this location leads to instability in the process, resulting in significant deviations in the cylindricity of the oil reservoir step and ultimately affecting the plunger's oil pumping accuracy. In view of this, the novel piston and oil pump of this application are proposed. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a new type of piston and oil pump that is easy to process with centerless grinding, effectively improves cylindricity, and thus improves the oil pumping accuracy.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] A novel piston has an axially oriented oil reservoir on one end face. An oil passage hole is radially oriented on the outer side wall of the end of the novel piston near the oil reservoir, and the oil passage hole communicates with the oil reservoir. A flat groove is also formed on the outer side wall of the oil passage hole, and the oil passage hole is located on the inner bottom wall of the flat groove. A gap is provided between the flat groove and the end face of the novel piston near the oil reservoir.

[0008] An oil pump includes the aforementioned novel piston and a pump body. The pump body has a groove, and the pump body is also provided with an oil inlet pipe and an oil outlet pipe communicating with the groove. The novel piston passes through the groove. When the novel piston is rotated and axially slid under force, the flat groove is cyclically connected to one of the oil inlet pipe and the oil outlet pipe.

[0009] Optionally, the flat groove includes a central groove and two side grooves, with the two side grooves located on the circumferential sides of the central groove, and the oil passage hole located on the central groove.

[0010] Optionally, the novel piston has a snap-fit ​​surface on the end away from the oil reservoir.

[0011] Optionally, the outer side wall of the novel piston is also provided with a slanted ring groove, and there is a gap between the slanted ring groove and the flat groove. A limiting post is provided on the inner side wall of the sliding groove, and the limiting post extends into the slanted ring groove.

[0012] Optionally, a sealing groove is also provided on the outer side wall of the novel piston. The sealing groove is located between the inclined ring groove and the flat groove. A sealing sleeve is fitted inside the sealing groove, and the sealing sleeve abuts against the inner side wall of the sliding groove.

[0013] Optionally, the pump body includes a housing and a sleeve. A central slot is provided inside the housing, and the sleeve is disposed in the central slot so that the inner side wall of the sleeve and the inner bottom wall of the central slot together form the sliding groove. The oil inlet pipe and the oil outlet pipe are both located on the housing.

[0014] Optionally, one end of the limiting post is engaged with the outer shell, and the other end of the limiting post passes through the sleeve to extend into the inclined annular groove.

[0015] Optionally, the sleeve has a first hole and a second hole along the radial direction, the first hole communicating with the oil inlet pipe and the second hole communicating with the oil outlet pipe.

[0016] Optionally, the first hole and the second hole are centrally symmetrical about each other with respect to the axis of the central slot.

[0017] Compared with the prior art, the present invention has at least the following advantages:

[0018] This invention relates to a novel piston and oil pump. The novel piston has an axially oriented oil reservoir on one end face. An oil passage hole is radially formed on the outer wall of the end of the piston near the oil reservoir, communicating with the oil reservoir. A flat groove is also formed on the outer wall of the oil passage hole, with the oil passage hole located on the inner bottom wall of the flat groove. A gap is provided between the flat groove and the end face of the piston near the oil reservoir. Thus, the flat groove of the novel piston is cylindrical, effectively supported during centerless grinding, resulting in good stability and improved surface rounding accuracy. Furthermore, because the novel piston has an overall cylindrical structure, the stability of the centerless grinder is effectively improved, allowing for processing using a through-feed centerless grinder, thereby increasing the processing efficiency. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a novel piston according to one embodiment of the present invention;

[0021] Figure 2 for Figure 1 A schematic cross-sectional view of the new type of piston is shown.

[0022] Figure 3 This is a schematic diagram of the structure of an oil pump according to one embodiment of the present invention;

[0023] Figure 4 for Figure 3 A schematic cross-sectional view of the oil pump shown.

[0024] Figure 5 for Figure 3 The diagram shows a partial structural schematic of the oil pump.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10. Oil pump; 100. New type piston; 110. Oil reservoir; 120. Oil passage hole; 130. Flat groove; 200. Pump body; 210. Slide groove; 310. Oil inlet pipe; 320. Oil outlet pipe; 131. Middle groove; 132. Side groove; 140. Snap-fit ​​surface; 150. Inclined ring groove; 410. Limiting post; 160. Sealing groove; 510. Sealing sleeve; 220. Outer shell; 230. Sleeve; 231. First hole; 232. Second hole. Detailed Implementation

[0027] To facilitate understanding of this utility model, a more comprehensive description will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this utility model.

[0028] like Figure 1 and Figure 2 As shown, a novel piston 100 has an oil reservoir 110 axially formed on one end face of the novel piston 100. An oil passage hole 120 is radially formed on the outer side wall of the end of the novel piston 100 near the oil reservoir 110. The oil passage hole 120 communicates with the oil reservoir 110. A flat groove 130 is also formed on the outer side wall of the novel piston 100 near the oil passage hole 120. The oil passage hole 120 is located on the inner bottom wall of the flat groove 130, and there is a gap between the flat groove 130 and the end face of the novel piston 100 near the oil reservoir 110.

[0029] It should be noted that an oil reservoir 110 is formed along the axial direction on one end of the novel piston 100, and an oil passage hole 120 is formed in the radial direction, with the oil passage hole 120 communicating with the oil reservoir 110. Furthermore, a flat groove 130 is formed on the outer wall near the oil passage hole 120, wherein the flat groove 130 is at a certain distance from the end face of the oil reservoir 110 of the novel piston 100. This means that the flat groove 130 and the oil passage hole 120 are both located in the middle of the new piston 100. The flat groove 130 does not directly connect with the end face of the new piston 100. Therefore, the overall structure of the new piston 100 is cylindrical. Thus, during centerless grinding, since the new piston 100 is cylindrical on both sides of the axial direction of the flat groove 130, the flat groove 130 is stably supported by the guide wheel during centerless grinding, preventing the flat groove 130 from being suspended. This ensures that all parts of the new piston 100, especially the flat groove 130, are effectively supported, thereby ensuring the stability of the new piston 100 during centerless grinding and improving the surface rounding accuracy of the new piston 100. Furthermore, in existing technologies, the plunger end face is concave due to the connection between the oil reservoir step and the plunger end face, thus limiting the processing of existing plungers to infeed centerless mills. However, the novel piston 100 of this application, with its overall cylindrical structure, significantly improves the stability of the centerless mill, allowing it to be processed using a through-feed centerless mill. Currently, infeed centerless mills typically grind one or two workpieces per infeed stroke, while through-feed centerless mills allow workpieces to enter one by one from the front end and exit sequentially from the rear end. Therefore, the novel piston 100 of this application, due to its structural improvement, can be processed using a through-feed centerless mill, effectively increasing grinding efficiency compared to infeed centerless mills.

[0030] like Figure 3 and Figure 4 As shown, an oil pump 10 includes a novel piston 100 and a pump body 200. The pump body 200 has a groove 210 inside. The pump body 200 is also provided with an oil inlet pipe 310 and an oil outlet pipe 320 that communicate with the groove 210. The novel piston 100 passes through the groove 210. When the novel piston 100 is rotated and axially slid under force, the flat groove 130 is cyclically connected to one of the oil inlet pipe 310 and the oil outlet pipe 320.

[0031] It should be noted that a groove 210 is provided inside the pump body 200, allowing the novel piston 100 to rotate within the groove 210 while also sliding axially. Specifically, when the novel piston 100 rotates one revolution in the groove 210, that is, 360°, within the range of 0° to 180°, the novel piston 100 moves outward axially while rotating; within the range of 180° to 360°, the novel piston 100 moves inward axially while rotating. When the novel piston 100 moves outward axially, the flat groove 130 connects with the oil inlet pipe 310. During this process, the space of the oil reservoir 110 within the groove 210 increases, generating negative pressure, thereby drawing engine oil from the oil inlet pipe 310 into the space of the oil reservoir 110. When the new piston 100 moves inward along the axial direction, the flat groove 130 connects with the oil outlet pipe 320. During this process, the space of the oil reservoir 110 within the slide groove 210 decreases, generating positive pressure. This causes the engine oil to flow out from the space of the oil reservoir 110 through the oil outlet pipe 320. Thus, as the new piston 100 rotates directionally in the slide groove 210, it can periodically reciprocate along the axial direction, thereby enabling the engine oil to be pumped in a directional and quantitative manner. Furthermore, because the cylindricity and diameter accuracy of the new piston 100 are improved, the assembly accuracy with the slide groove 210 is enhanced, avoiding the problem of small gaps and preventing jamming when the new piston 100 and the slide groove 210 move relative to each other. This improves the pumping accuracy of the engine oil and effectively reduces oil leakage from the oil pump 10.

[0032] like Figure 1 As shown, in one embodiment, the flat groove 130 includes a central groove 131 and two side grooves 132, with the two side grooves 132 located on both sides of the central groove 131 in the circumferential direction, and the oil passage hole 120 located on the central groove 131.

[0033] It should be noted that when the novel piston 100 rotates directionally within the slide groove 210, in order to ensure that the flat groove 130 has sufficient range to communicate with the oil inlet pipe 310 and the oil outlet pipe 320, the flat groove 130 is configured with a structure in which the central groove portion 131 is connected to two side groove portions 132. Specifically, when the novel piston 100 rotates, one side groove portion 132 first connects to the oil inlet pipe 310, or the other side groove portion 132 first connects to the oil outlet pipe 320. This ensures that the flat groove 130 has sufficient circumferential width.

[0034] like Figure 3 As shown, in one embodiment, the novel piston 100 has a snap-fit ​​surface 140 on the end away from the oil reservoir 110.

[0035] It should be noted that when the oil pump 10 is installed on a chainsaw, a drive source such as an engine is needed to rotate the new piston 100 in a specific direction. To ensure a stable connection between the new piston 100 and the drive source, a snap-fit ​​surface 140 is machined on the outer wall of the end of the new piston 100 away from the oil reservoir 110. It should be noted that since the diameter of the snap-fit ​​surface 140 is smaller than the diameter of the flat groove 130, the location of the snap-fit ​​surface 140 will not affect the overall stability of the new piston 100 when the maximum outer diameter of the new piston 100 is rounded.

[0036] like Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, in one embodiment, the outer side wall of the novel piston 100 is also provided with an oblique ring groove 150, and there is a gap between the oblique ring groove 150 and the flat groove 130. A limiting post 410 is provided on the inner side wall of the sliding groove 210, and the limiting post 410 extends into the oblique ring groove 150.

[0037] It should be noted that the above structure is designed to allow the novel piston 100 to rotate directionally within the groove 210 while simultaneously sliding reciprocally along the axial direction. Specifically, an inclined annular groove 150 is formed on the outer wall of the novel piston 100. The inclined annular groove 150 is inclined on the outer wall of the novel piston 100, and the limiting post 410 mounted on the pump body 200 extends into the inclined annular groove 150. Thus, when the novel piston 100 is subjected to force and rotates, because the limiting post 410 always extends into the inclined annular groove 150 and pushes against the inner wall of the inclined annular groove 150, the novel piston 100 can simultaneously rotate directionally and slide reciprocally along the axial direction, ultimately enabling the oil pump 10 to pump oil stably and accurately.

[0038] like Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, in one embodiment, a sealing groove 160 is also provided on the outer side wall of the novel piston 100. The sealing groove 160 is located between the inclined ring groove 150 and the flat groove 130. A sealing sleeve 510 is provided inside the sealing groove 160, and the sealing sleeve 510 abuts against the inner side wall of the sliding groove 210.

[0039] It should be noted that in order to improve the sealing of the new piston 100 sliding in the slide groove 210, a sealing sleeve 510 is installed to effectively prevent oil from seeping out from the tiny gaps between the new piston 100 and the slide groove 210.

[0040] like Figure 4 As shown, in one embodiment, the pump body 200 includes a housing 220 and a sleeve 230. A central groove is provided in the housing 220, and the sleeve 230 is disposed in the central groove so that the inner side wall of the sleeve 230 and the inner bottom wall of the central groove together form a sliding groove 210. The oil inlet pipe 310 and the oil outlet pipe 320 are both located on the housing 220.

[0041] It should be noted that while the groove 210 requires precision machining, the machining accuracy of other parts of the pump body 200 can be appropriately reduced. Higher machining accuracy leads to higher manufacturing costs. Therefore, to ensure the machining accuracy of the groove 210 while reducing the manufacturing cost of the pump body 200, the pump body 200 is designed as a combination of a housing 220 and a sleeve 230. The sleeve 230 requires precision machining to form the groove 210; therefore, it is designed with a small size to facilitate machining and reduce material usage, thus lowering costs. The housing 220 needs to be mounted on a chainsaw, resulting in a complex external structure. Separately molding the parts and then assembling them reduces manufacturing difficulty and costs.

[0042] In one embodiment, one end of the limiting post 410 is engaged with the outer casing 220, and the other end of the limiting post 410 passes through the sleeve 230 to extend into the inclined annular groove 150. For example, a through hole is provided in the radial direction of the sleeve 230 so that the limiting post 410 can pass through the through hole to extend into the inclined annular groove 150.

[0043] like Figure 4 As shown, in one embodiment, the sleeve 230 has a first hole 231 and a second hole 232 radially provided. The first hole 231 is connected to the oil inlet pipe 310, and the second hole 232 is connected to the oil outlet pipe 320.

[0044] It should be noted that the sleeve 230 is fixedly installed with the outer shell 220. When the new piston 100 rotates and slides axially, the flat groove 130 can be connected to the oil inlet pipe 310 through the first hole 231, or to the oil outlet pipe 320 through the second hole 232.

[0045] In one embodiment, the first hole 231 and the second hole 232 are centrally symmetrically distributed with respect to the axis of the central groove. This ensures that when the novel piston 100 rotates in a specific direction, the flat groove 130 communicates with the first hole 231 and the second hole 232 for the same duration, thereby accurately and stably pumping oil.

[0046] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the utility model patent. Unless otherwise specifically defined, the installation / fixing / setting mentioned in this utility model can be understood as including, but not limited to, locking and fixing with screws / bolts, welding, or bonding with adhesives, wherein the adhesives used can be commercially available finished products. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A novel piston, characterized in that: An oil reservoir is provided axially on one end face of the novel piston. An oil passage hole is provided radially on the outer side wall of the end of the novel piston near the oil reservoir. The oil passage hole communicates with the oil reservoir. A flat groove is also provided on the outer side wall of the novel piston located at the oil passage hole. The oil passage hole is located on the inner bottom wall of the flat groove, and there is a gap between the flat groove and the end face of the novel piston near the oil reservoir.

2. An oil pump, characterized in that, The invention includes the novel piston as described in claim 1, and also includes a pump body, wherein a sliding groove is provided in the pump body, and an oil inlet pipe and an oil outlet pipe communicating with the sliding groove are also provided on the pump body. The novel piston passes through the sliding groove, and when the novel piston is rotated and axially slid under force, the flat groove is cyclically connected to one of the oil inlet pipe and the oil outlet pipe.

3. The oil pump according to claim 2, characterized in that, The flat groove includes a central groove and two side grooves, with the two side grooves located on the circumferential sides of the central groove, and the oil passage hole located on the central groove.

4. The oil pump according to claim 2, characterized in that, The novel piston has a snap-fit ​​surface on the end away from the oil reservoir.

5. The oil pump according to claim 2, characterized in that, The new piston also has a slanted ring groove on its outer side wall, and there is a gap between the slanted ring groove and the flat groove. A limit post is provided on the inner side wall of the sliding groove, and the limit post extends into the slanted ring groove.

6. The oil pump according to claim 5, characterized in that, A sealing groove is also provided on the outer side wall of the new piston. The sealing groove is located between the inclined ring groove and the flat groove. A sealing sleeve is fitted inside the sealing groove, and the sealing sleeve abuts against the inner side wall of the sliding groove.

7. The oil pump according to claim 5, characterized in that, The pump body includes a housing and a sleeve. A central slot is provided inside the housing. The sleeve is disposed in the central slot so that the inner side wall of the sleeve and the inner bottom wall of the central slot together form the sliding groove. The oil inlet pipe and the oil outlet pipe are both located on the housing.

8. The oil pump according to claim 7, characterized in that, One end of the limiting post is engaged with the outer shell, and the other end of the limiting post passes through the sleeve to extend into the inclined annular groove.

9. The oil pump according to claim 7, characterized in that, The sleeve has a first hole and a second hole along the radial direction. The first hole is connected to the oil inlet pipe, and the second hole is connected to the oil outlet pipe.

10. The oil pump according to claim 9, characterized in that, The first hole and the second hole are centrally symmetrical about each other with respect to the axis of the central slot.

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