A plunger type pressure limiting valve

Abstract

The present invention provides a plunger type pressure limiting valve, comprising a valve body, a plunger, a spring, a sealing ring, and a screw plug; the valve body is provided with a valve hole, and a first oil inlet hole, an oil drain hole, and a second oil inlet hole communicated with the valve hole; the plunger comprises a large diameter section and a small diameter section, the large diameter section and the valve hole are in clearance fit, the small diameter section is inserted into the sealing ring after passing through the spring, and is in clearance fit with the inner hole of the sealing ring, and the outer peripheral surface of the sealing ring and the valve hole are in transition fit; the screw plug comprises an outer section and an inner section, the outer section is provided with an external thread, the inner section is provided with a radial oil through hole, the end face of the inner end of the screw plug is provided with an axial blind hole, and the blind hole intersects with the oil through hole; the first oil inlet hole is communicated with the inner end of the valve hole, the oil drain hole corresponds to the peripheral surface of the large diameter section of the plunger, the second oil inlet hole corresponds to the inner section of the screw plug, and there is a gap between the inner section and the inner wall of the valve hole; the first oil inlet hole and the second oil inlet hole are both used to access high-pressure oil. The present invention can prevent the pressure limiting valve from opening prematurely at high speed.

Description

Technical Field

[0001] The invention relates to a lubrication system of an internal combustion engine, in particular to a plunger type pressure limiting valve for an oil pump. Background Art

[0002] When the internal combustion engine is working, each friction pair needs oil to provide lubrication and cooling in time. At present, the engine oil pump widely uses a metering pump. The flow rate provided by the metering pump will increase with the increase of engine speed. However, when the engine exceeds a certain speed when working, the lubricating cooling oil required will not change much. At this time, the excess oil provided by the metering pump must be discharged in time, otherwise the excessive oil pressure will damage the engine seals, and will also produce excess unnecessary resistance to the engine operation, reducing the engine's working efficiency.

[0003] Traditional engine oil pumps will be equipped with a pressure limiting valve to limit the pumping pressure of the oil. However, there are pressure fluctuations when the oil pump is working. The pressure fluctuations will gradually increase with the increase of speed, and the frequency will also increase, which will produce unnecessary impact on the pressure limiting valve, causing the pressure limiting valve to open prematurely at high speeds. Therefore, the opening pressure of the traditional pressure limiting valve will be specified to open at a certain speed during calibration. In this way, the opening pressure will be higher than the calibration value at low speeds, and the opening pressure will be lower than the calibration value at high speeds, which is very unfavorable for the management of engine oil pressure. In order to better manage the oil pressure, some mid-to-high-end engines currently use variable displacement oil pumps. Variable displacement oil pumps can change the displacement of the oil pump through the ECU according to the oil pressure feedback of the oil channel, and accurately control the pumping flow and pressure of the oil pump to ensure the lubrication and cooling needs of the engine. Energy consumption can also be reduced by changing the displacement, but variable displacement oil pumps have a complex structure and high cost, which makes it difficult to popularize and promote them in large quantities. Summary of the invention

[0004] The object of the present invention is to provide a plunger type pressure limiting valve to prevent the pressure limiting valve from opening prematurely at a high rotation speed.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present invention is: a plunger type pressure limiting valve, including a valve body, a plunger, a spring, a sealing ring, and a screw plug; the valve body is provided with a valve hole for accommodating the plunger, the spring, the sealing ring and the screw plug, and is provided with a first oil inlet hole, an oil drain hole and a second oil inlet hole communicated with the valve hole; the plunger is a stepped shaft, including a large diameter section and a small diameter section, the large diameter section and the inner wall of the valve hole are clearance-matched, the small diameter section passes through the spring and is inserted into the sealing ring, the inner hole of the sealing ring and the small diameter section are clearance-matched, and the outer peripheral surface of the sealing ring is clearance-matched with the valve There is a transition fit between the holes; the screw plug includes an outer section and an inner section, the outer section is provided with an external thread, the inner section is provided with a radial oil hole, and the end face of the inner end of the screw plug is provided with an axial blind hole, and the blind hole intersects with the oil hole; the first oil inlet hole is communicated with the inner end of the valve hole, the opening position of the oil drain hole corresponds to the circumferential surface of the large diameter section of the plunger, and the opening position of the second oil inlet hole corresponds to the inner section of the screw plug, and there is a gap between the inner section and the inner wall of the valve hole; the first oil inlet hole and the second oil inlet hole are both used to connect high-pressure oil.

[0006] The working principle of the above technical solution is: when the oil pump reaches the calibrated opening pressure of the pressure limiting valve, the high-pressure oil from the high-pressure chamber of the oil pump can push the plunger to compress the spring and move to the spring side. When the end face of the large-diameter section of the plunger moves to the position of the oil drain hole, the pressure limiting valve enters the opening mode, and part of the high-pressure oil in the high-pressure chamber of the oil pump can be drained to the oil pan through the oil drain hole, so that the main oil channel of the engine is maintained at the opening pressure calibrated by the pressure limiting valve. Since the plunger includes a large-diameter section and a small-diameter section, two plunger end faces, one large and one small, will be formed. The high-pressure oil coming from the first oil inlet hole and the second oil inlet hole acts on the two plunger end faces respectively, and the oil pressure force on the large plunger end face must be greater than that on the small plunger end face. According to the pressure calculation formula: P=F / S, the force on the large plunger end face is Flarge=P*Slarge, the force on the small plunger end face is Fsmall=P*Ssmall, and the spring compression force is F', then Flarge=Fsmall+F'. The spring force F' will increase linearly with the spring pressure. Since both plunger end faces are affected by the high-pressure oil, the pressure fluctuations they experience are the same. Therefore, as the speed increases, the pressure fluctuations increase, and F small + F' also increases nonlinearly. This can greatly improve the situation where the pressure limiting valve opens in advance at high speeds, making the opening pressure of the pressure limiting valve infinitely smaller with the speed change, allowing the oil pump outlet to maintain a constant pressure supply, so that the oil pump outflow and pressure can be accurately controlled to ensure the engine lubrication and cooling requirements, and also reduce energy consumption.

[0007] In one embodiment, the valve hole is equipped with a plunger, a spring, a sealing ring, and a screw plug in sequence from the inside to the outside, and the end surface of the large-diameter section of the plunger corresponds to the first oil inlet hole.

[0008] In one embodiment, the sealing ring and the screw plug are integrally formed.

[0009] Furthermore, a damping hole is provided on the valve body at a position corresponding to the spring. In the actual working process, a small amount of high-pressure oil acting on both ends of the plunger will leak from the gap between the large-diameter section of the plunger and the valve hole and from the gap between the small-diameter section and the inner hole of the sealing ring to the middle of the valve hole. The existence of the damping hole can discharge the oil in time, avoiding the formation of damping between the plunger and the sealing ring, which affects the opening pressure of the pressure-limiting valve.

[0010] Furthermore, an annular chip pressure balancing groove is provided on the circumferential surface of the plunger large diameter section.

[0011] Furthermore, an annular spring installation recessed groove is provided on the end surface of the plunger where the large diameter section and the small diameter section are connected.

[0012] The beneficial effect achieved by the present invention is that the pressure-limiting valve provided by the present invention can introduce high-pressure oil to act on the large and small end surfaces of the plunger at the same time, so that the compression force on the spring side also increases nonlinearly, thereby suppressing the phenomenon of premature opening of the pressure-limiting valve under high-speed conditions, thereby allowing the quantitative pump to also have the ability to stably control the main oil channel pressure under different speed conditions, and the structure is simple and reliable, with obvious cost advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the overall structure of the pressure limiting valve in Examples 1 and 2 of the present invention;

[0014] Figure 2 Schematic diagram of the plunger structure of the pressure limiting valve in Examples 1 and 2 of the present invention;

[0015] Figure 3 Schematic diagram of the plug screw structure of the pressure limiting valve in Example 1 of the present invention;

[0016] Figure 4 This is an exploded schematic diagram of the overall structure of the pressure limiting valve in Example 1 of the present invention;

[0017] The accompanying drawings are marked as follows:

[0018] 1——valve body 11——first oil inlet hole 12——oil drain hole

[0019] 13——Second oil inlet hole 14——Damping hole

[0020] 2—— plunger 21—— large diameter section 22—— small diameter section

[0021] 23——Chip pressure balance groove 24——Spring installation sink groove

[0022] 3——Spring 4——Sealing ring 5——Screw plug

[0023] 51——External thread 52——Oil hole 53——Blind hole. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0025] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicate orientations or positional relationships as shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the terms can be understood according to the specific circumstances.

[0027] Example 1

[0028] like Figures 1 to 4 A plunger-type pressure-limiting valve shown in the figure comprises a valve body 1, a plunger 2, a spring 3, a sealing ring 4 and a screw plug 5; the valve body 1 is provided with a valve hole, and is provided with a first oil inlet hole 11, an oil drain hole 12, a second oil inlet hole 13 and a damping hole 14 which are communicated with the valve hole, and the valve hole is provided with a plunger 2, a spring 3, a sealing ring 4 and a screw plug 5 in sequence from the inside to the outside; the plunger 2 is a stepped shaft, comprising a large-diameter section 21 and a small-diameter section 22, the large-diameter section 21 and the inner wall of the valve hole are clearance-fitted, the small-diameter section 22 passes through the spring 3 and is inserted into the sealing ring 4, the inner hole of the sealing ring 4 and the small-diameter section 22 are clearance-fitted, and the outer peripheral surface of the sealing ring 4 and the inner wall of the valve hole are transitionally fitted; the screw plug 5 comprises an outer section and an inner section, the outer section is provided with an external thread 51, and the inner section is provided with a There is a radial oil through hole 52, and an axial blind hole 53 is provided on the end face of the inner end of the screw plug 5, and the blind hole 53 intersects with the oil through hole 52; the first oil inlet hole 11 is connected to the inner end of the valve hole and corresponds to the end face of the large diameter section 21 of the plunger, the opening position of the oil drain hole 12 corresponds to the circumferential surface of the large diameter section 21 of the plunger, and the opening position of the second oil inlet hole 13 corresponds to the inner section of the screw plug 5, and there is a gap between the inner section and the inner wall of the valve hole, and the position of the damping hole 14 corresponds to the installation position of the spring 3; the first oil inlet hole 11 and the second oil inlet hole 13 are both used to connect high-pressure oil; the circumferential surface of the large diameter section 21 of the plunger is provided with an annular chip pressure balancing groove 23, and the end face of the end of the large diameter section 21 of the plunger connected to the small diameter section 22 is provided with an annular spring installation recessed groove 24.

[0029] The working principle of this embodiment is: when the oil pump reaches the calibrated opening pressure of the pressure limiting valve, the high-pressure oil from the high-pressure chamber of the oil pump can push the plunger 2 to compress the spring 3 and move to the spring side. When the end face of the large-diameter section 21 of the plunger moves to the position of the oil drain hole 12, the pressure limiting valve enters the opening mode, and part of the high-pressure oil in the high-pressure chamber of the oil pump can be drained to the oil pan through the oil drain hole 12, so that the main oil channel of the engine is maintained at the opening pressure calibrated by the pressure limiting valve. Since the plunger includes a large-diameter section 21 and a small-diameter section 22, two plunger end faces, one large and one small, will be formed. The high-pressure oil coming from the first oil inlet hole 11 and the second oil inlet hole 13 acts on the two plunger end faces respectively, and the oil pressure force on the large plunger end face must be greater than that on the small plunger end face. According to the pressure calculation formula: P=F / S, the force on the large plunger end face is Flarge=P*Slarge, the force on the small plunger end face is Fsmall=P*Ssmall, and the spring compression force is F', then Flarge=Fsmall+F'. The spring force F' will increase linearly with the spring pressure. Since both the end faces of the two plungers are affected by the high-pressure oil, the pressure fluctuations they experience are consistent. Therefore, as the speed increases, the pressure fluctuations increase, and F small + F' also increases nonlinearly. This can greatly improve the situation where the pressure limiting valve opens in advance at high speeds, so that the opening pressure of the pressure limiting valve becomes infinitely smaller with the speed change, and the oil pump outlet is kept at a constant pressure supply. In this way, the oil pump flow rate and pressure can be accurately controlled to ensure the lubrication and cooling requirements of the engine, and energy consumption can also be reduced. During the working process, a small amount of high-pressure oil acting on both ends of the plunger will leak from the gap between the large diameter section 21 of the plunger and the valve hole and from the gap between the small diameter section 22 and the inner hole of the sealing ring 4 to the middle of the valve hole. The existence of the damping hole 14 can discharge these oils in time to avoid the formation of damping between the plunger and the sealing ring 4, which affects the opening pressure of the pressure limiting valve.

[0030] Example 2

[0031] The overall structure of this embodiment is substantially the same as that of the first embodiment, except that the sealing ring 4 and the screw plug 5 are integrally formed.

[0032] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

[0033] In order to make it easier for ordinary technicians in the field to understand the improvements of the present invention over the prior art, some drawings and descriptions of the present invention have been simplified, and for the sake of clarity, some other elements are omitted in this application document. Ordinary technicians in the field should realize that these omitted elements may also constitute the content of the present invention.

Claims

1. A plunger type pressure limiting valve, characterized in that: The invention comprises a valve body (1), a plunger (2), a spring (3), a sealing ring (4), and a screw plug (5); the valve body (1) is provided with a valve hole, and is provided with a first oil inlet hole (11), an oil drain hole (12), and a second oil inlet hole (13) which are communicated with the valve hole; the valve hole is provided with a plunger (2), a spring (3), a sealing ring (4), and a screw plug (5) in sequence from the inside to the outside; the plunger (2) is a stepped shaft, comprising a large diameter section (21) and a small diameter section (22); the large diameter section (21) and the inner wall of the valve hole are clearance-matched; the end face of the large diameter section (21) corresponds to the first oil inlet hole (11); the small diameter section (22) passes through the spring (3) and is inserted into the sealing ring (4); a clearance is formed between the inner hole of the sealing ring (4) and the small diameter section (22). The outer circumferential surface of the sealing ring (4) and the inner wall of the valve hole are in transitional fit; the screw plug (5) comprises an outer section and an inner section, the outer section is provided with an external thread (51), the inner section is provided with a radial oil through hole (52), the end surface of the inner end of the screw plug (5) is provided with an axial blind hole (53), the blind hole (53) intersects with the oil through hole (52); the first oil inlet hole (11) is in communication with the inner end of the valve hole, the opening position of the oil drain hole (12) corresponds to the circumferential surface of the large diameter section (21), the opening position of the second oil inlet hole (13) corresponds to the inner section of the screw plug (5), and there is a gap between the inner section and the inner wall of the valve hole; the first oil inlet hole (11) and the second oil inlet hole (13) are both used to connect high-pressure oil.

2. The plunger type pressure limiting valve according to claim 1, characterized in that: The sealing ring (4) and the screw plug (5) are integrally formed.

3. The plunger type pressure limiting valve according to claim 1 or 2, characterized in that: A damping hole (14) is also provided on the valve body (1) at a position corresponding to the spring (3).

4. The plunger type pressure limiting valve according to claim 1 or 2, characterized in that: An annular chip pressure balancing groove (23) is provided on the circumferential surface of the large diameter section (21).

5. The plunger type pressure limiting valve according to claim 1 or 2, characterized in that: An annular spring installation recessed groove (24) is provided on the end surface of the large diameter section (21) at one end connected to the small diameter section.

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