Oil seal structure for valve rod of natural gas engine

Abstract

The utility model discloses a natural gas engine valve rod oil seal structure which comprises a measuring cup, the top of the measuring cup is fixedly connected with an upper seat through a bolt, the top of the upper seat is in interference fit with a valve guide pipe, a valve rod penetrates through the top of the valve guide pipe, and an oil seal assembly is arranged on the top of the surface of the valve rod. The top of the upper seat is fixedly connected with a spring base, the top of the surface of the valve rod is fixedly connected with a spring top seat through a lock clamp, and a valve spring is arranged between the spring base and the spring top seat. The oil seal assembly comprises a rubber ring, and the rubber ring is arranged on the surface of the valve rod in a sleeving mode. The valve rod oil seal is simple in structure, the manufacturing cost is reduced, and the valve rod oil seal can strictly control the leakage amount of engine oil; the problems that engine oil is lost due to large leakage of the engine oil and the valve guide pipe cannot be lubricated due to small leakage of the engine oil are effectively solved.

Description

Technical Field

[0001] This utility model belongs to the field of natural gas engine technology. Specifically, this utility model relates to a valve stem oil seal structure for a natural gas engine. Background Technology

[0002] Currently, among various engine products, natural gas engines are becoming increasingly widely used due to their low gas price, good operating economy, and clean emissions. However, as the power of natural gas engines increases and the combustion temperature rises, valve guide wear can cause the valves to be slightly pushed open under hot conditions. This not only affects the high-temperature gas seal but also leads to cylinder head valve cracking under the continuous scouring of high-temperature gases. Cylinder head valve cracking in natural gas engines has become an industry-wide technical challenge for the development of natural gas engines.

[0003] The main functions of valve stem seals are twofold: firstly, to prevent engine oil from entering the intake and exhaust pipes, thus avoiding oil loss; secondly, oil leakage is beneficial for the lubrication of valve guides. The design must allow for some oil leakage from the valve stem seals, but the leakage rate needs to be strictly controlled. Excessive oil leakage leads to further oil loss, while minimal leakage does not provide adequate lubrication of the valve guides. Therefore, evaluating the leakage rate of the valve stem seals per unit time and verifying the consistency of the leakage rate is crucial.

[0004] Therefore, there is an urgent need for a simple and low-cost device that can quickly test the leakage of valve stem oil seals per unit time, verify the consistency of valve stem oil seal leakage, and thus determine whether the valve stem oil seals can meet the engine performance requirements. Utility Model Content

[0005] This invention provides a valve stem oil seal structure for a natural gas engine, which solves the problems mentioned in the background art.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a valve stem oil seal structure for a natural gas engine, including a measuring cup, an upper seat fixedly connected to the top of the measuring cup by bolts, a valve guide being interference-fitted to the top of the upper seat, a valve stem penetrating through the top of the valve guide, an oil seal assembly being provided on the top of the valve stem surface, a spring base being fixedly connected to the top of the upper seat, a spring top seat being fixedly connected to the top of the valve stem surface by a locking clip, and a valve spring being provided between the spring base and the spring top seat;

[0007] The oil seal assembly includes a rubber ring, which is sleeved on the surface of the valve stem. A ring spring is sleeved on the surface of the rubber ring. An oil lip is connected to the bottom of the rubber ring, and an air lip is connected to the bottom of the oil lip. A skeleton is fixedly connected to the bottom of the outer ring of the oil lip.

[0008] Preferably, an air passage is provided on one side of the upper seat.

[0009] Preferably, the measuring cup is provided with an O-ring at the top.

[0010] The beneficial effects of adopting the above technical solutions are:

[0011] 1. This utility model has a simple structure and reduces costs. The valve stem oil seal can strictly control the amount of oil leakage; it effectively avoids the problem that large oil leakage leads to oil loss, while small oil leakage fails to lubricate the valve guide. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure provided by this utility model;

[0013] Figure 2 This is an overall sectional view of the present invention;

[0014] Figure 3 This is a cross-sectional view of the oil seal assembly of this utility model;

[0015] in:

[0016] 1. Measuring cup; 2. Upper seat; 3. Valve guide; 4. Valve stem; 5. Oil seal assembly; 6. Spring base; 7. Locking clip; 8. Spring top seat; 9. Valve spring; 10. Air passage; 11. O-ring;

[0017] 51. Rubber ring; 52. Ring spring; 53. Oil lip; 54. Air lip; 55. Skeleton. Detailed Implementation

[0018] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of this utility model, and to facilitate its implementation.

[0019] like Figures 1 to 3 As shown, this utility model is a valve stem oil seal structure for a natural gas engine. It has the advantages of simple structure, reduced cost, and strict control of oil leakage. It effectively avoids the problems of excessive oil leakage leading to oil loss and insufficient lubrication of valve guides due to insufficient oil leakage.

[0020] Specifically, such as Figures 1 to 3As shown, it includes a measuring cup 1, the top of the measuring cup 1 is fixedly connected to an upper seat 2 by bolts, the top of the upper seat 2 is interference-fitted with a valve guide 3, the top of the valve guide 3 passes through a valve stem 4, the top of the surface of the valve stem 4 is provided with an oil seal assembly 5, the top of the upper seat 2 is fixedly connected with a spring base 6, the top of the surface of the valve stem 4 is fixedly connected with a spring top seat 8 by a locking clip 7, and a valve spring 9 is provided between the spring base 6 and the spring top seat 8.

[0021] The oil seal assembly 5 includes a rubber ring 51, which is sleeved on the surface of the valve stem 4. A ring spring 52 is sleeved on the surface of the rubber ring 51. An oil lip 53 is connected to the bottom of the rubber ring 51. An air lip 54 is connected to the bottom of the oil lip 53. A skeleton 55 is fixedly connected to the bottom of the outer ring of the oil lip 53.

[0022] An air passage 10 is provided on one side of the upper seat 2.

[0023] An O-ring 11 is provided on the top of the measuring cup 1.

[0024] The specific working method is described below using specific embodiments: Example 1

[0025] The valve stem 4 is limited by the spring top seat 8, the locking clip 7, the valve spring 9, and the spring base 6; the valve guide 3 is interference-fitted onto the upper seat 2, the valve stem oil seal 5 is assembled onto the valve guide 3, the air passage 10 simulates the engine intake pressure, and the gas is pressurized; it is driven by the drive wheel to simulate the actual operating state of the engine. Example 2

[0026] The working state of the valve stem seal in the engine was simulated using valve guide 3, valve stem 4, locking clip 7, and seal assembly 5. The seal was assembled according to the actual working state. The valve guide seat was connected to the test bench according to the actual working state. During the experiment, the gas pressure in the measuring cup changed alternately to simulate the working pressure state of the valve stem seal in the engine. Filter paper was placed in the measuring cup, and the oil dripping from the guide rod was collected within a specified time. The weight of the filter paper before and after the experiment was measured by electronic balance, and the difference was the test leakage amount. The leakage amount per unit time was calculated.

[0027] The leakage rate is calculated using the following formula: Q = (W2 – W1) / T

[0028] Where: Q = oil leakage rate (grams / hour)

[0029] W2 = Weight of the filter paper (grams) after the experiment.

[0030] W1 = Weight of filter paper (grams) before the experiment begins

[0031] T = Test time (hours)

[0032] Test results

[0033] Valve stem seal testing points: temperature and pressure. Natural gas engines have higher temperatures and more oil leakage. Theoretically, intake and exhaust valve stem seals should be designed separately because the different temperatures result in different oil leakage rates.

[0034] Evaluation criteria: The leakage rate of valve stem seals per unit time should meet the following requirements: 0.001-0.0035 g / h.

[0035] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A valve stem oil seal structure for a natural gas engine, comprising a measuring cup (1), characterized in that: The top of the measuring cup (1) is fixedly connected to the upper seat (2) by bolts. The top of the upper seat (2) is press-fitted with a valve guide (3). The top of the valve guide (3) is through a valve stem (4). An oil seal assembly (5) is provided on the top of the surface of the valve stem (4). A spring base (6) is fixedly connected to the top of the upper seat (2). A spring top seat (8) is fixedly connected to the top of the surface of the valve stem (4) by a locking clip (7). A valve spring (9) is provided between the spring base (6) and the spring top seat (8). The oil seal assembly (5) includes a rubber ring (51), which is sleeved on the surface of the valve stem (4). A ring spring (52) is sleeved on the surface of the rubber ring (51). An oil lip (53) is connected to the bottom of the rubber ring (51). An air lip (54) is connected to the bottom of the oil lip (53). A skeleton (55) is fixedly connected to the bottom of the outer ring of the oil lip (53).

2. The valve stem oil seal structure for a natural gas engine according to claim 1, characterized in that: An air passage (10) is provided on one side of the upper seat (2).

3. The valve stem oil seal structure for a natural gas engine according to claim 1, characterized in that: The top of the measuring cup (1) is provided with an O-ring (11).

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