JPH0343467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump for an internal combustion engine.

For example, US Patent No. 31955465 and Utility Model No.
The known fuel injection pump disclosed in Publication No. 51-53310 is provided with a constant pressure valve that opens in the direction of fuel flow toward the fuel injection valve and a relief valve that opens in the opposite direction. The closing spring of the valve is supported by a threaded member secured within a sleeve-like section of the valve closing body of the constant pressure valve.
However, this screw connection formation has the following drawbacks. In other words, the reliable functioning of the fuel injection pump may be impaired because the threaded connections may come loose, and if the valve part falls into the pump working chamber, it may cause major damage to the fuel injection pump and, by extension, to the internal combustion engine. There are things to do.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fuel injection pump in which a relief valve can be easily attached and detached from a closing body of a constant pressure valve.

In order to solve this problem, the design of the fuel injection pump for internal combustion engines according to the invention provides a pump piston delimiting the working chamber and a first pressure conduit leading to the fuel injection valve. A constant pressure valve is provided which opens in the direction of fuel injection conveyance against the force of a closing spring of the constant pressure valve, the constant pressure valve having a movable valve closing body guided in a valve holder, and further comprising a movable valve closing body guided in a valve carrier. A relief valve configured as a stop valve is provided, the relief valve being adapted to be compressed in the direction of fuel conveyance against the force of a second closing spring supported via a yoke on the valve closing body of the constant pressure valve. It has a movable valve closing member that opens in the opposite direction, and when the valve closing member faces the valve seat surface disposed on the valve closing body of the constant pressure valve, it opens in a second direction.
The yoke is pressed by the closing spring of
a second closing spring mounted in two openings in the wall of the valve closing body of the constant pressure valve at right angles to the longitudinal axis of said valve closing body and cooperating with a movable valve closing member of the relief valve; is supported in the central section of the yoke, and the spring receiver for the second closing spring is received in a recess provided in the central section of the yoke.

By the embodiment of the invention, the disadvantages of the known technology, which is the starting point for the invention, are avoided in simple ways and reliably even under adverse operating conditions. The present invention utilizes the hollow cylindrical wall of the valve closing body of a constant pressure valve as a support, and supports the spring in a recess provided in the center of the yoke, thereby simultaneously avoiding displacement of the yoke. It is based on the idea that

According to an advantageous embodiment of the invention, the opening accommodating the yoke is drilled through the cylindrical wall of the valve closing body of the constant pressure valve at right angles to the longitudinal axis of the valve closing body of the constant pressure valve. It is formed by a hole. With this configuration, a bearing part that can be manufactured easily is obtained.

Moreover, the structure according to claims 3 and 4 improves the flow of fuel and ensures reliable operation and assembly of the yoke, which is inexpensively produced as a press-formed product, for example.

Next, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a fuel injection pump for an internal combustion engine is provided with a constant pressure valve 9, the valve holder 12 of the constant pressure valve has a valve seat in the form of an annular surface, and the pump Cylindrical sleeve 11 within casing 10
and the pressing member 14. The annular surface 13 of the movable valve closing body 15 is connected to the first closing spring 17
is pressed toward the valve seat of the valve holder 12. The valve closing member 15 has a hollow cylindrical wall 16, and the cylindrical wall 16 is closed to the valve holder 1 by a plurality of ribs 18 provided on the outside of the cylindrical wall 16.
Guided within 2.

The relief valve 19, which functions as a check valve, mainly has the following functions:
a movable valve closing member 19a configured as a ball;
It is formed by an annular valve seat surface 20 provided on the valve closing body 15. The valve closing body 15 further includes:
It has an expanding passage 21 leading to each fuel injector (not shown) and opening into a pressure conduit, indicated symbolically by arrow 22. Partially illustrated pump piston 3 of a fuel injection pump
6 is guided in a cylindrical sleeve 11,
It limits the working chamber 23 for the injected fuel. The movable valve closing member 19a of the relief valve 19 is pressed toward the valve seat surface 20 of the valve closing body 15 of the constant pressure valve 9 via the first spring receiver 33 by the second closing spring 28, In the illustrated embodiment, a second spring receiver 27 is provided on the yoke 24, which is configured as a bar-shaped member.
is supported through.

The basic cross-sectional shape of the yoke 24 is approximately circular. The yoke 24 has a central section 26 with a relief valve 1
a flat recess 25 for receiving a spring receptacle 27 for a second closing spring 28 of 9; Each side has one chamfered portion 30. Two diametrically opposed openings 31 in the hollow cylindrical wall 16 serve as bearings for the yoke 24. Both openings 31 are formed by holes drilled through the valve closing body 15 at right angles to the longitudinal axis 32 of the valve closing body 15, which is at the same time the axis of the pump piston 36. By locating the spring receiver 27 within the recessed portion 25, displacement of the yoke 24 is reliably avoided.

Both ends 29 of the yoke 24 are supported in openings 31 and two further chamfers 34 are provided on the sides of the yoke 24 in order to increase the return cross-sectional area. The double-sided chamfer 34 extends parallel to the longitudinal axis of the yoke 24 and to the longitudinal axis 32 of the valve closing body 15 (see FIG. 2). Due to this shape which improves the flow through, the yoke 24 can be easily grasped and assembled. Furthermore, the yoke 24 can be manufactured as an inexpensive press molded product. The basic cross-sectional diameter of the yoke 24 is the opening 3
1, so that a sufficiently large support surface 35, which is one section of the cylindrical outer circumferential surface, remains for supporting the yoke 24 in the opening 31.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged longitudinal sectional view of a fuel injection pump according to the invention equipped with a constant pressure valve, and FIG.
FIG. 3 is a partial view of the valve closing body seen in the direction of the arrow in the figure; 9... constant pressure valve, 10... pump casing, 11...
Cylindrical sleeve, 12... Valve retainer, 13... Annular surface,
14... Pressing member, 15... Valve closing body, 16... Cylindrical wall, 17, 28... Closing spring, 18... Rib, 19...
Relief valve, 19a... Valve closing member, 20... Valve seat surface, 21... Passage, 22... Arrow, 23... Working chamber, 2
4... Yoke, 25... Recessed portion, 26... Center section, 2
7, 33... Spring receiver, 29... End, 30, 34...
Chamfered portion, 31... Opening, 32... Vertical axis, 35... Support surface, 36... Pump piston.

Claims (1)

Claims: 1. A fuel injection pump for an internal combustion engine, comprising a pump piston 36 delimiting a working chamber 23 and a first pressure conduit 22 leading to a fuel injection valve. A constant pressure valve 9 is provided which opens in the fuel conveying direction against the force of a closing spring 17 and has a movable valve closing body 15 guided in a valve holder 12. Furthermore, a relief valve 19, which is configured as a check valve, is provided, which acts against the force of a second closing spring 28, which is supported via a mork 24 on the valve closing body of the constant-pressure valve. It has a movable valve closing member 19a that opens in the opposite direction to the fuel conveyance direction, and when the valve closing member 19a faces the valve seat surface 20 disposed on the valve closing body 15 of the constant pressure valve 9, it opens in the second direction. It is biased by a closing spring 28 and the yoke 24 is mounted in two openings 31 in the wall 16 of the valve closing body 15 of the constant pressure valve 9 at right angles to the longitudinal axis 32 of the valve closing body 15. and
A second closing spring 28 , which cooperates with the movable valve closing member 19 a of the relief valve 19 , is supported in the central section 26 of the yoke 24 , and a spring receiver 27 for the second closing spring 28 is located on the yoke 24 . Central section 26
A fuel injection pump for an internal combustion engine, characterized in that the pump is received in a recess 25 provided in the engine. 2. An opening 31 accommodating the yoke 24 is drilled through the cylindrical wall 16 of the valve closing body 15 of the constant pressure valve 9 at right angles to the longitudinal axis 32 of said valve closing body 1
The fuel injection pump according to claim 1, wherein the fuel injection pump is formed by two holes. 3. The yoke 24 is formed as a rod-shaped member having a circular basic cross-sectional shape and a diameter corresponding to the diameter of the hole forming the opening 31, and has recessed portions 25 at both ends of the yoke 24, respectively. 3. The fuel injection pump according to claim 2, wherein the fuel injection pump has at least one chamfer 30 located in a plane parallel to . 4 The yoke 24 additionally has its longitudinal axis 1
3 and two chamfered portions 34 parallel to the longitudinal axis 32 of the valve closing body 15 of the constant pressure valve 9,
The fuel injection pump according to claim 3, wherein the fuel injection pump is supported within the opening 31 by a support surface 35 that is a part of the cylindrical outer peripheral surface.