JP4612264B2 - Distributive injection pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a distribution-type injection pump, which includes a casing and a roller ring that is adjustably disposed in the casing. The roller ring includes at least one roller. A cam disk which can be supported for the operation of the pump piston, and in which the roller is supported in the roller ring by a pin extending radially with respect to the central axis of the roller ring About.
[0002]
This type of distributed injection pump is useful for supplying the correct amount of fuel to the cylinders of an internal combustion engine at the correct time. For this purpose, a pump piston connected to the cam disc is provided. When the cam disk rotates relative to the roller ring, the surface with the protrusion rolls on the roller. In this manner, the cam disk performs a stroke movement, which is transferred to the pump piston. Due to the force acting on the pin during the stroke movement, a periodic component force is applied to the pin that loads the pin radially outward with respect to the central axis of the roller ring. This means that when the roller ring is heavily loaded, the end of the casing, which is usually made of aluminum, is located opposite the end of the casing, which is usually made of aluminum, in the radial direction. It is driven into or pushed into. This may impair the functional reliability of the injection pump in the long term.
[0003]
The object of the present invention is therefore to improve an injection pump of the type described at the outset so that the pushing of the pin of the roller ring into the casing of the distributed injection pump is reliably prevented.
[0004]
Advantages of the Invention In the distributed injection pump having the features of claim 1, the support element is used to introduce the axial force acting on the pin into the casing of the distributed injection pump through a large surface. This significantly reduces the wear force that acts locally from the pin to the casing, so that material damage can be minimized.
[0005]
In an advantageous embodiment of the invention, the support element is a clip clipped into an opening in the roller ring. The clip covers the outer end in the radial direction of the pin, and when an axial force is applied to the pin, the clip is deformed outward toward the casing of the distribution type injection pump, and as a result, abuts the casing. An axial force acting on the pin is introduced into the casing through a large surface. Steel is preferably selected as the material for the clip.
[0006]
According to a further embodiment, the support element is arranged in the casing. In this embodiment, the support element made of steel is preferably formed as an insert, which prevents direct contact between the steel pin and the aluminum casing. In this embodiment as well, the axial force acting on the pin is first transmitted to the support element and then introduced from the support element into the casing via a large surface.
[0007]
Advantageous configurations of the invention are evident from the dependent claims.
[0008]
The invention will now be described with reference to the preferred embodiments shown in the accompanying drawings.
[0009]
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a schematic partial cross-sectional view of a distributed injection pump according to the present invention, which is useful for injecting fuel into a cylinder of an internal combustion engine. The injection pump has a casing 10 in which a roller ring 12 is arranged. This roller ring has an inner ring 14 and an outer ring 16, and the inner ring and the outer ring form a ring-shaped receiving portion 18 therebetween. A plurality of rollers 20 are arranged inside the ring-shaped receiving part 18, and each of these rollers is supported on a pin 24 via one bush 22. Each pin 24 extends radially with respect to the central axis of the roller ring 12 and is received in the inner ring 14 at its radially inner end and within the outer ring 16 at its radially outer end. Is accepted. A thrust washer 26 is further disposed between the outer ring 16 and each roller 20.
[0010]
Cam disk 28 is in cooperation with the roller 20, the cam disc is loaded on the roller 20 by a compression spring 30. A protrusion 32 is coupled to the cam disk 28, and this protrusion is coupled to a pump piston (not shown).
[0011]
A drive shaft 36 is provided, and this drive shaft can rotate the cam disk 28 via a clutch 38. The cam disk 28 faces the roller 20 and rolls on the roller 20 on the surface provided with the cam projection, and as a result, a periodic stroke motion of the cam disc 28 occurs, and this stroke motion is transferred to the pump piston. Then, the pump piston finally discharges the fuel.
[0012]
In order to adjust the injection point in relation to the crank angle of the supplied internal combustion engine, an injection governor (not shown) is further provided, which causes the roller ring 12 to rotate within the casing by a predetermined angle. Can be moved. The structure and function of this type of injection governor is generally known and will therefore not be described here.
[0013]
Mounted on the roller ring 12 is a support element 40 (see also FIGS. 2 and 3), which has two bent ends 42, which serve as spring shackles. Each bent end engages in an opening 44 formed in the outer ring 16 of the roller ring 12. The support element 40 extends over an angular range significantly greater than the angular range in which the radially outward ends of the corresponding pins 24 extend, and is positioned radially outward of the corresponding pins. The edges to be covered are marked. In order to prevent the support elements 40 from projecting beyond the outer periphery of the outer ring 16, each support element is within one notch 46 extending between two openings 44 arranged corresponding to the same support element 40. Is arranged.
[0014]
When a large force is applied to the roller 20 during operation of the distribution type injection pump, an axial force acting in the direction of arrow F in FIG. As a result of this, the pin 24 pushes the support element 40 outward when the pin 24 is propelled, so that the support element is supported by the casing 10 of the dispensing jet pump. In this way, a large contact surface is produced, through which an acting axial force can be introduced into the casing.
[0015]
In particular, steel can be used as the material of the support element 40. Alternatively, the use of suitable plastics is also considered. Unlike the illustrated embodiment, where a separate support element is used for each pin, the use of a single support element for all pins is also contemplated. Furthermore, instead of the illustrated support element made of flat material, for example, a wire clip can be used, in which case the wire surrounds all the outer rings and is in the region of the end located axially outside the pin 24. Or are each clipped into the opening 44 separately.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a part of a distributed injection pump according to the present invention.
FIG. 2 is a perspective view of a portion of a roller ring used in the distributed injection pump of FIG.
FIG. 3 is a perspective view of a part of the roller ring as seen from another angle.

Claims (5)

A distributor type injection pump, the casing (10), this is adjustably arranged roller ring in the casing (12) is provided, the roller ring (12) is at least one roller (20) This roller (20) can be supported by a cam disc (28) which serves for the operation of the pump piston, and the roller (20) is in relation to the central axis of the roller ring (12) A bearing element (40) is supported on the roller ring (12) at the radially outer end of the pin (24), supported in the roller ring (12 ) by a radially extending pin (24). In the format that is arranged ,
Distributive jet pump, characterized in that the support element (40) is a clip clipped in an opening (44) provided in the roller ring (12) . Wherein the clip is a spring clip according to claim 1, distributor injection pump according. 3. Distributive injection pump according to claim 1 or 2 , characterized in that the roller ring (12) is provided with a notch (46) for the support element (40). Support element (40) is characterized in that it consists of metal, distributor injection pump of any one of claims 1 to 3. 5. Distributive injection pump according to any one of claims 1 to 4 , characterized in that the support element (40) is made of plastic.

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