JPS58174152A - Fuel injection pump of internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the force to be required to drive an injection pump by making the pump plunger in a small size with its dimension in the axial direction. CONSTITUTION:No.1 arm 24 and No.2 arm 46 are molded solidly as in a single piece in such an arrangement as pinching a cam 42, being given an angular form as a whole, and they are coupled with each other solidly as in a single piece so that their free ends are restricted from separating from the cam 42. A weak spring 52 is stretched over between No.2 arm 46 and husing 10, and No.1 arm 24 and No.2 arm 46 are energized in such a direction that No.1 roller 28 mounted at the free end of No.1 arm 24 will be put in engagement with the cam 42. Therefore the pump plunger 22 can operate faithfully in compliance with the curve of cam 42 even around the upper dead point of plunger 22 regardless of the inertia force of plunger 22 or any external force.

Description

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

A pump plunger whose one end is slidably fitted into a pressure-feeding cylinder, a camshaft that rotates while being located at the upper center of the pump plunger in a plane perpendicular to the axis, and a fl A fuel injection pump for an internal combustion engine is provided, which includes a cam that reciprocates the pump plunger based on the rotational movement of the camshaft, and pumps fuel by the reciprocating movement of the pump plunger. Such a fuel injection pump is equipped with a strong return spring located coaxially with the pump plunger for pressing the cam roller provided at the lower end of the pump plunger against the cam, and the reciprocating movement of the pump plunger is caused by the cam of the cam. I try to follow the curve and do it faithfully. That is, when the convex part of the cam passes the cam roller, a return spring is provided to press the cam roller against the cam and drive the pump plunger in a non-compressing direction. The cam roller tends to separate from the cam due to the inertia of the cam, causing a so-called jumping phenomenon.
A strong spring is provided to prevent this.

However, according to such conventional fuel injection pumps,
Since a strong return spring is provided, a large driving force is required to operate the fuel injection pump, and the provision of the spring increases the size of the fuel injection pump in the axial direction of the pump plunger. There was an inconvenience. In particular, in fuel injection pumps that require high-speed rotation, the spring must be made even stronger, the size of the fuel injection pump becomes even larger, and, for example, the fuel injection pump and fuel injection nozzle must be integrated. In order to attach such a unit to the cylinder head, the engine block had to be significantly modified, increasing the size of the engine and posing a major obstacle to the practical use of the unit.

The present invention has been made against the background of the above circumstances, and its purpose is to provide a fuel injection pump for an internal combustion engine in which the axial dimension of the bomb pump is small and the driving power is small. .

In order to achieve such an object, the gist of the present invention is as follows: (1) The free end is engaged with a cam and swung around an axis parallel to the cam shaft, and the other end of the pump plunger (2) a first arm coupled to a first arm that imparts a reciprocating motion to the pump plunger in accordance with a cam curve of the cam; (2) a first arm having a free end engaged with the cam and swinging about an axis parallel to the cam axis; (8) interconnecting the first arm and the second arm to prevent the free ends of these arms from separating from the cam; The pump plunger is provided with a connecting means to allow the pump plunger to reciprocate faithfully in accordance with the cam curve of the cam regardless of its inertia.

In this way, the lower end of the pump plunger
The first arm is connected to the arm and holds the cam together with the second arm.
Since it is connected to the arm, the reciprocating movement of the pump plunger can be made faithfully following the cam curve of the cam without the need for a strong return spring. Therefore, the space necessary for arranging a strong return spring is no longer required, and the axial dimensions of the pump plunger of the fuel injection pump are significantly reduced, and the space necessary for compressing the strong return spring is reduced significantly. Since no power is required, the load for driving the fuel injection pump is reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below based on the drawings.

In FIG. 1 and FIG. 2, the housing 10 of the fuel injection pump has a pressure cylinder (de-onjabare) v1.
2 is fixed, and the plunger barrel 12 is provided with a cylinder bore 14 passing through the plunger barrel 12 in the longitudinal direction and a suction port 16 passing through the peripheral wall of the plunger barrel 12.

A cylindrical pinion 18 with teeth on the outer periphery is rotatably fitted into the lower part of the plunger barrel 12, and a control rack 20 extending in a direction perpendicular to the pinion 18 is engaged with the pinion 18. I'm Sera T. The upper end of the pump plunger 22 is fitted into the cylinder pore 14 so as to be movable in the axial direction, and the lower end of the pump plunger 22 is fitted into the first arm 2.
4, and reciprocating motion is applied by the first arm 24. That is, the pump plunger 22
In the lower 4 parts of the
A first pin 80 is formed at the free end of the first arm 24 to rotatably support a tenth lug 28 that engages with a cam 42, which will be described later, and to be inserted into the elongated hole. It is installed protrudingly.

A prismatic portion 82 having a rectangular cross section is provided at an intermediate position of the bonding plunger 22, and the prismatic portion 32 is fitted into a square hole provided at the lower end of the pinion 18. The bond plunger 22 is the pinion 18
The pinion 18 is movable relative to the pinion 18 in the axial direction.
It can also be rotated around the axis.

A diagonal groove 8 is formed on the outer peripheral surface of the pump plunger 22.
4 is formed, and a passage 36 communicating between the groove 84 and the upper end surface is provided, and the pump plunger 22
The effective fuel pumping torque can be changed by changing the rotation angle around the axis of the fuel pump. Therefore, when the pinion 18 rotates as the control rack 20 moves in the axial direction, the bonding plunger 22 is rotated around the axis, and the amount of fuel pumped is adjusted.

Here, the elongated hole 26 connects the pump plunger 22 to the first arm 24 by not only allowing the arcuate movement of the first pin 80 but also allowing rotation of the pump plunger 22 itself. Note that 88 is a delivery valve.

A cam shaft 40 is disposed near the lower end of the bond plunger 22 and is located in a plane perpendicular to the longitudinal direction of the bond plunger 22.
2 is provided. An arm shaft 44 parallel to the cam shaft 40 is fixed to the housing 10, and the first arm 24
And a second arm 46 is attached to be rotatable around the arm shaft 44. A second pin 48 is protruded from the free end of the second arm 46, and a 20th lug 50 that engages with the cam 42 is rotatably supported by the second pin 48.

As shown in detail in FIG.
The arm 46 is integrally molded in a dogleg shape with the cam 42 in between, and the first arm 24 and the second arm 46 are integrally connected to each other, and the free ends of the first arm 24 and the second arm 46 are is restrained from separating from the cam 42. A weak spring 52 is stretched between the second arm 46 and the housing 10, and the second arm 52 is stretched in the direction in which the tenth arm 28 attached to the free end of the seventeenth arm 24 engages with the cam 42. The first arm 24 and the second arm 46 are energized.

The operation of this embodiment will be explained below.

When the camshaft 40 is rotated by an internal combustion engine (not shown), the cam 42 rotates from the state of (a) to the state of (b) in FIG. Rotate to push up the pump plunger 22. When the pump plunger 22 is pushed up to its maximum position, the second arm 46 that rotates together with the first arm 24 moves to the opposite side of the cam 42. 28 at the free end of the first arm 24 is restricted from moving away from the cam 42.

Normally, in such a case, the load for pumping the fuel is applied in the direction of pushing down the bond plunger 22, so no force is generated in the free end of the first arm 24 in the direction of separating it from the cam 42. , even if such a force is applied for some reason, the second arm 46
- The 28 is prevented from being separated from the cam 42. Therefore, even near the top dead center of the pump plunger 22, the pump plunger 22 is moved faithfully according to the cam curve of the cam 42, regardless of the inertia force or external force of the pump plunger 22.

When the cam 42 rotates further and reaches the state shown in FIG. be rotated. This first arm 24, which is integrally fixed with the second arm 46, causes the pump plunger 22 to be pulled down even though it is not provided with a strong return spring. As a result, together with the biasing force of the spring 58, the tenth part 28 engages with the cam 42, resulting in the states from (f) to (g) in FIG. 4, and the pump plunger 22
At the same time as the filtration pump plunger arm 46 is rotated, it is forcibly driven to the bottom dead center according to the cam curve of the cam 42, and
Near the bottom dead center, the 10th roller 28 and the 20th roller 50 are prevented from separating from the cam 42 by the connection of the first arm 24 and the second arm 46, so that the pump plunger 22, etc. This eliminates the jerking phenomenon of the pump plunger 22, regardless of the inertial force or external force.

That is, even if the camshaft 40 is driven to rotate at high speed and is operated at a high fuel pumping rate, the pump plunger 22 is driven back and forth faithfully according to the cam curve of the cam 42.

In this way, the first arm 24 and the second arm 46 mutually restrict their range of motion, and the first arm 24 raises the pump plunger 22 while the second arm 46 raises the pump plunger 2.

The receiver has a stroke of lowering the pump plunger 2 and gives a reciprocating motion to the pump plunger 22 according to the cam curve of the cam 42. For this reason, as shown in the conventional example in FIG.
Since there is no need to provide a strong return spring 56 for biasing the cam roller 54 toward the cam 42 and for reciprocating the pump plunger 22 faithfully following the cam curve of the cam 42, The size of the fuel injection pump can be reduced and the power required to drive the fuel injection pump can be reduced. Especially when high speed rotation is required,
without requiring a strong return spring 56,
The pump plunger 22 can be reciprocated according to the cam curve of the cam 42, and even when the unit that integrally combines the fuel injection pump and the fuel injection nozzle shown in FIG. No major changes are required, and the unit can be assembled into the engine relatively easily.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-mentioned embodiments are given the same reference numerals and the description thereof will be omitted.

In FIG. 6, the first arm 24 and the second arm 46
are independently rotatably attached to each other by a common arm shaft 44, and a spring 58 is stretched between the first arm 24 and the second arm 46.
Thus, the first arm 24 and the second arm 46 are elastically connected.

Therefore, when the state shown in FIG. 7 to FIG. 8 is reached according to the rotation of the cam 42, the pump plunger 22 is lifted up to the top dead center by the rotation of the first arm 24, and the free end of the first arm 24 is moved toward the cam. Movement away from 42 is restricted by spring 58. Similarly, when the pump plunger 22 is in a downward state, the second arm 46 is pushed down by the cam 42, and at the same time the first arm 46 is pushed down by the cam 42.
Arm 24 is rotated in the same direction as second arm 46.

In this way, according to this embodiment, the first arm 24 and the second
Since the arm 46 is connected to the arm 46 by an elastic connection means, there is an advantage that the tenth roller 28 and the twentieth roller 50 are always engaged with the cam surface of the cam 42.

In FIG. 9, the arm shaft 44 is connected to the force. %@400 The fuel injection timing is adjusted by moving it around the central axis. That is, the camshaft 4° is provided with an adjustment arm 60 that is rotatable relative to the camshaft 40 turns υ, and the adjustment arm 6o is provided at the free end of the adjustment arm 6o and rotates in an arc centered on the central axis of the camshaft 40. The first arm 24 and the second arm 46 are rotatably attached to an arm shaft 44 whose position is adjusted along the arm shaft 44. A rack 62 formed along an arc coaxial with the center of the camshaft 40 is fixed to the free end of the adjustment arm 60, and the rack 62 is rotated by a pinion 64 by a drive device (not shown). are interlocked with. That is, by rotating the pinion 64, the pump plunger 22 can be adjusted, or in other words, the fuel injection timing for each cylinder can be adjusted very easily. The reference numeral 66 is a nine-ply ring stretched between the second arm 46 and a protrusion protruding from the adjustment arm 60.

According to this embodiment, the ignition timing is changed by the offset interval between the center line parallel to the pump plunger 22 passing through the center of the camshaft 4o and the center line parallel thereto passing through the center of the 10th roller 28. Therefore, the movement angle of the injection timing can be changed at a rate of about 1/8 to 115 times the rotation angle of the adjustment arm 6o, making it easy to make fine adjustments and adjusting the ignition timing extremely easily. .

Although the embodiment of the present invention has been described above based on the drawings, the present invention can be applied to other embodiments as well.

For example, the first arm 24 and the second arm 46 are rotatably provided on different cam shafts parallel to each other, and a link or a spring is provided between the first arm 24 and the second arm 46. They can also be connected.

Further, the spring 52 in the above-mentioned embodiment is not necessarily necessary, and a certain effect can be obtained even without it.

In addition, the above-mentioned friend is just one embodiment of the present invention,
The present invention may be modified in various ways without departing from its spirit.

As described in detail above, according to the fuel injection pump for an internal combustion engine of the present invention, the nine first parts are engaged with the cam and are swingably provided.
Since the arm and the second arm are arranged to sandwich the cam and are connected to each other by a connecting means, a strong return spring is required to make the pump plunger follow the cam surface of the cam. The pump plunger connected to the first arm is reciprocally driven faithfully according to the cam curve of the cam. Therefore, there is no need to install a strong return spring.
The axial dimensions of the pump plunger of the fuel injection pump have been reduced, making it possible to integrate the fuel injection pump and the injection nozzle and attaching the unit to the engine. can be reduced. In particular, when the fuel injection pump is driven at high speed, a large return spring is required, so this effect is significant.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a main part of a fuel injection pump for an internal combustion engine showing one embodiment of the present invention, and FIG. 2 is a top view of FIG. 1. FIG. 3 is an enlarged view of the main parts in FIG. 1. FIG. 4 is a diagram illustrating the operation of the embodiment shown in FIG. 1. FIG. 5 is a diagram corresponding to FIG. 1 in the conventional example. FIG. 6 is a diagram corresponding to FIG. 8 showing another embodiment of the present invention, and FIGS. 7 and 8 are diagrams for explaining the operation of the embodiment in FIG. 6. FIG. 9 is a diagram corresponding to FIG. 8 showing another embodiment of the present invention. 12 Nibfunja barrel (pressure feeding cylinder) 22: Pump plunger 24: First arm 40: Cam shaft
42: Cam 44: Arm shaft 46:
Second arm 58 spring (connection means) Applicant Toyota Motor Corporation

Claims (1)

[Scope of Claims] (1) A pump plunger whose one end is slidably fitted into a pressure-feeding cylinder; A fuel injection pump for an internal combustion engine, which includes a cam provided on a camshaft and reciprocates the pump plunger based on the rotational movement of the camshaft, and which pumps fuel by the reciprocating movement of the pump plunger, the free end of which is connected to the cam. The front E-phone 7" is engaged with the front E-phone 7" and is swung around an axis parallel to the camshaft.
a first arm connected to the other end of the 7" plunger to impart reciprocating motion to the pump plunger in accordance with the cam curve of the cam; and a first arm having a free end engaged with the cam and having an axis parallel to the cam axis. a second arm that is pivoted to sit and sandwich the nuclear force 4 together with the first arm; the first arm and the second arm are interconnected; the free ends of the arms are spaced apart from the cam; (2) A fuel injection pump for an internal combustion engine, characterized in that the pump plunger is driven reciprocally in accordance with the cam curve of the cam regardless of its inertia. Claim 1, wherein the first arm and the second arm are provided to be swingable around a common arm axis, and the connecting means integrally fixes the first arm and the second arm. The fuel injection pump for an internal combustion engine according to Item 8. (8) The first arm and the second arm are provided so as to be able to swing independently around a common arm axis, and the connecting means The fuel injection pump for an internal combustion engine according to claim 1, which is a nupling stretched between an arm and a second arm. (4) The first arm and the second arm are connected to the camshaft. Claims in which the fuel injection device is swingably supported by an arm shaft whose position is adjustable within a certain angle range along a circular arc that is coaxial with the axis, and the fuel injection timing is adjusted according to the position of the shaft. A fuel injection pump for an internal combustion engine according to any one of items 1 to 3.