A fuel inlet valve mounting structure for a high-pressure fuel injection pump

Abstract

The present invention discloses an oil inlet valve installation structure for a high-pressure fuel injection pump, comprising a plunger sleeve, a plunger, and an oil inlet valve core assembly; the oil inlet valve core assembly comprises a valve stem, a spring seat, an oil inlet valve spring, and a valve core integrated with the valve stem; the top of the plunger sleeve is provided with a through hole coinciding with the center of the plunger, and the valve stem is slidably installed in the through hole; a volume chamber is integrally provided on the plunger sleeve, and the oil inlet buffer is connected to the oil inlet channel arranged on the plunger sleeve; a sealing gland is screwed on the volume chamber; the upper end of the valve stem is located in the volume chamber, and a spring seat is fixedly installed at the end of the valve stem in the volume chamber, and the oil inlet valve spring is installed between the spring seat and the top of the plunger platform. The present invention integrates the oil inlet valve seat and the plunger sleeve into one, eliminates the installation joint surface between the traditional valve seat and the plunger sleeve, and eliminates the risk of high-pressure leakage here. In addition, the volume chamber added by the present invention reduces the impact on the oil inlet valve core assembly, and ensures the stability of the oil inlet valve core.

Description

Technical Field

[0001] The invention belongs to a diesel engine fuel injection system, and in particular relates to an oil inlet valve installation structure for a high-pressure fuel injection pump of a common rail system. Background Art

[0002] The high-pressure fuel injection pump (hereinafter referred to as the high-pressure pump) of the common rail system of a diesel engine is the core component of the fuel injection system. The structure of the pump oil system, the core fuel supply component, determines the reliability and product life of the fuel pump to a certain extent.

[0003] The oil pump system is a key component of the high-pressure pump, responsible for converting low-pressure fuel into high-pressure oil. The oil inlet valve and the plunger sleeve are connected by compression to form a closed fuel volume chamber. Please refer to Figure 2 Long-term high-pressure repeated impacts may cause fuel leakage on this sealing surface, thus affecting the reliability and life of the oil pump.

[0004] In traditional high-pressure pumps, the oil inlet valve assembly is assembled in the plunger sleeve by compression to form a closed fuel volume chamber. As the common rail pressure increases, the risk of high-pressure leakage at the joint surface of the oil inlet valve assembly and the plunger sleeve increases. Once a high-pressure leakage occurs, the high-pressure pump will experience insufficient oil supply, pressure drop, or even no oil supply, which will cause system failure.

[0005] To this end, the present invention provides a method that eliminates the mounting interface between the traditional valve seat and the plunger sleeve, thereby eliminating the risk of high pressure leakage therein. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides an installation structure of an oil inlet valve for a high-pressure fuel injection pump.

[0007] The present invention is achieved in this way. An oil inlet valve installation structure for a high-pressure fuel injection pump comprises a plunger sleeve, the plunger sleeve is provided with an oil inlet port and an oil outlet port, a plunger is installed in a plunger cavity of the plunger sleeve, and also comprises an oil inlet valve core assembly; the oil inlet valve core assembly comprises a valve stem, a spring seat, an oil inlet valve spring and a valve core integrated with the valve stem, characterized in that a through hole is provided at the top of the plunger sleeve and coincides with the center of the plunger, a valve stem is slidably installed in the through hole; a conical sealing surface is provided in the plunger cavity and matches the sealing surface of the valve core; a volume cavity is integrally provided on the plunger sleeve at the outer circumference of the through hole, the volume cavity is communicated with an oil inlet channel arranged on the plunger sleeve; a sealing gland is screwed on the volume cavity; the upper end of the above-mentioned valve stem is located in the volume cavity, a spring seat is fixedly installed at the end of the valve stem in the volume cavity, and an oil inlet valve spring is installed between the spring seat and the top of the plunger platform.

[0008] Preferably, the spring seat and the valve stem are in interference fit.

[0009] The advantages and technical effects of the present invention are as follows: the valve seat and the plunger sleeve of the oil inlet valve are designed to be an integrated structure, and the oil inlet valve core is directly installed in the top through hole of the plunger sleeve to realize the oil inlet function; since the valve seat and the plunger sleeve of the oil inlet valve are integrated into one, the mounting joint surface between the traditional valve seat and the plunger sleeve is eliminated, thereby eliminating the risk of high-pressure leakage here; in addition, the volume chamber added by the present invention reduces the impact on the oil inlet valve core assembly, thereby ensuring the stability of the oil inlet valve core. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the structure of the present invention;

[0011] Figure 2 It is a schematic diagram of the prior art structure.

[0012] In the figure, 1, plunger sleeve; 1-1, oil inlet; 1-2, oil outlet; 1-3, through hole; 1-4, conical sealing surface; 1-5, volume chamber; 1-6, oil inlet channel; 2, plunger; 3, oil inlet valve core assembly; 3-1, valve stem; 3-2, spring seat; 3-3, oil inlet valve spring; 3-4, valve core; 4, sealing cover; 5, valve seat. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] See also Figure 1, an oil inlet valve installation structure for a high-pressure fuel injection pump, comprising a plunger sleeve 1, the plunger sleeve is provided with an oil inlet port 1-1 and an oil outlet port 1-2, a plunger 2 is installed in the plunger cavity of the plunger sleeve, and also includes an oil inlet valve core assembly 3; the oil inlet valve core assembly 3 includes a valve stem 3-1, a spring seat 3-2, an oil inlet valve spring 3-3 and a valve core 3-4 integrated with the valve stem, the top of the plunger sleeve is provided with a through hole 1-3 coinciding with the center of the plunger, and the valve stem is slidably installed in the through hole; a conical sealing surface 1-4 cooperating with the valve core sealing surface is provided in the plunger cavity; it is equivalent to merging the oil inlet valve seat and the plunger sleeve into one, eliminating the installation joint surface between the traditional valve seat and the plunger sleeve, and eliminating the risk of high-pressure leakage here. In addition, a volume cavity 1-5 is integrally provided on the plunger sleeve on the outer circumference of the through hole, and the volume cavity is connected to the oil inlet channel 1-6 provided on the plunger sleeve; a sealing gland 4 is screwed on the volume cavity, and the structure is relatively simple; the upper end of the valve stem is located in the volume cavity, and a spring seat 3-2 is fixedly installed at the end of the valve stem in the volume cavity, and the fixing method of the spring seat and the valve stem is preferably interference fit, but not limited to this, and can also be fixedly connected by means of pins, snap rings, etc.; an oil inlet valve spring 3-3 is installed between the spring seat and the top of the plunger platform. By controlling the press-fit height of the oil inlet valve spring seat, the preload force of the oil inlet valve spring 3-3 is controlled, and then the opening pressure of the oil inlet valve is controlled. In actual operation, when the plunger moves downward, the oil inlet valve opens, and the fuel enters the plunger cavity; when the plunger moves upward, the oil inlet valve closes, and the fuel is pressurized and sent to the oil outlet, and is supplied to the outside at high pressure through the pipeline.

[0015] The present invention designs the valve seat and the plunger sleeve of the oil inlet valve into an integrated structure, and the oil inlet valve core is directly installed in the through hole at the top of the plunger sleeve to realize the oil inlet function. At the same time, the mounting joint surface between the traditional valve seat and the plunger sleeve is eliminated, thereby eliminating the risk of high-pressure leakage here. In addition, the volume cavity added by the present invention reduces the impact on the oil inlet valve core assembly, thereby ensuring the stability of the oil inlet valve core.

[0016] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An oil inlet valve installation structure for a high-pressure fuel injection pump, comprising a plunger sleeve, the plunger sleeve is provided with an oil inlet port and an oil outlet port, a plunger is installed in the plunger cavity of the plunger sleeve, and also comprises an oil inlet valve core assembly; the oil inlet valve core assembly comprises a valve stem, a spring seat, an oil inlet valve spring and a valve core integrated with the valve stem, characterized in that: A through hole coinciding with the center of the plunger is provided at the top of the plunger sleeve, and a valve stem is slidably installed in the through hole; a conical sealing surface cooperating with the valve core sealing surface is provided in the plunger cavity; a volume cavity is integrally provided on the outer circumference of the through hole and located on the plunger sleeve, and the volume cavity is connected with the oil inlet channel arranged on the plunger sleeve; a sealing gland is screwed on the volume cavity; the upper end of the above-mentioned valve stem is located in the volume cavity, and a spring seat is fixedly installed at the end of the valve stem in the volume cavity, and an oil inlet valve spring is installed between the spring seat and the top of the plunger platform.

2. The fuel inlet valve installation structure for a high-pressure fuel injection pump according to claim 1 is characterized in that: The spring seat and the valve stem are interference fit.

Images