JP2000192825A - Fuel metering device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regulate vibration in the vertical direction of a rack pin to eliminate torque shortage, improve the response property of a centrifugal governor, and reduce production cost in a simple manner. SOLUTION: This device is constituted in such a way that a fork lever 1 is connected to a metering rack 6 of a fuel injection pump 5 through a rack pin 7 in the interlocking relationship and the fork lever 1 is oscillated by tensile force of a governor spring and governor force to move the metering rack 6 for metering through the rack pin 7 so as to adjust an amount. A pressing spring 10 is pressed against and is brought into contact with the rack pin 7 to regulate deflection of the metering rack 6 in the direction of travel and cross.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel metering device for a diesel engine, and more particularly to improving the responsiveness of a centrifugal governor by eliminating the vertical swing of a rack pin (the swing in the direction crossing the movement of a metering rack). Related to technology.

[0002]

2. Description of the Related Art Conventionally, as a fuel metering device for a diesel engine, there is a fuel metering device shown in FIG. 4 (hereinafter referred to as "conventional example"). Here, FIG. 4A is a drawing of a main part of a centrifugal governor, and this fuel metering device is shown in FIG.
As shown in FIG. 1A, a fork lever 1 is interlockedly connected to a metering rack 6 of a fuel injection pump (not shown) via a rack pin 7 so that a tension S of a governor spring 4 and a governor force G of a governor weight are used. The fork lever 1 is swung to move the metering rack 6 via the rack pin 7. In FIG. 4A, reference numeral 3 denotes a starting increasing spring, 16 denotes a spring pressing member, and F denotes a biasing force of the starting increasing spring.

[0003]

In the prior art described above, the contact surface 1a of the fork lever 1 is tilted forward with respect to the rack pin 7 by the swinging posture of the fork lever 1 [FIG.
(B)] or the backward inclined posture (FIG. 4C). In the forwardly inclined posture (FIG. 4B), an obliquely downward reaction force N is generated on the contact surface 1a, and a component force for pushing the rack pin 7 downward acts. In addition, a backward tilting posture (FIG. 4C)
In this case, an obliquely upward reaction force N is generated on the contact surface 1a, and a component force that pushes the rack pin 7 upward acts. These component forces cause the rack pin 7 to oscillate in the vertical direction (i.e., the oscillation of the metering rack in the direction crossing the movement).

[0004] That is, as shown in FIG. 4 (D), since a gap is inevitably present between the control pinion 13 of the fuel injection pump 5 and the metering rack 6, the rack pin 7 is pushed upward or downward. Is caused in the movement of the metering rack 6 in the movement cross direction Z. As shown in FIG. 3, this vibration causes a deviation as shown by a broken line in the shaft torque curve K, which should be smooth, which results in a shortage of the torque and lowers the responsiveness of the centrifugal governor.

[0005] In order to solve such inconveniences, the present applicant has previously proposed a fork lever shown in FIG. 5 (Japanese Patent Laid-Open No. 8-193527: hereinafter, this is referred to as a "prior proposal example"). The example proposed earlier is a fork lever 1
Is formed in a cycloid curve so that the contact angle α with the rack pin 7 is always constant even if the swing angle θ of the fork lever 1 changes.

However, this prior proposal has not been implemented since the pin contact surface 1a of the fork lever 1 is formed in a cycloidal curve, resulting in high production costs. The present invention has been made in view of such circumstances, and (a) eliminates vertical vibration of a rack pin (vibration in the direction crossing the movement of a metering rack), and furthermore, solves the shortage of torque to reduce the responsiveness of a centrifugal governor. And (b) to provide a device that can be easily implemented with reduced production costs.

[0007]

The present invention is configured as follows to solve the above-mentioned problems. That is, the first aspect of the present invention provides a metering rack 6 for the fuel injection pump 5.
The fork lever 1 is interlocked and connected via a rack pin 7, and the fork lever 1 is swung by the tension S of the governor spring 4 and the governor force G of the governor weight 8 to meter the metering rack 6 via the rack pin 7. In the fuel metering device for a diesel engine, which is configured to be moved, a pressing spring 10 is pressed against the rack pin 7 so as to restrict the deflection of the metering rack 6 in the movement cross direction Z. It is characterized by the following.

According to a second aspect of the present invention, in the fuel metering device for a diesel engine according to the first aspect, one end 10a of the pressing spring 10 is fixed, the intermediate portion 10c is supported by a fulcrum pin 12, and the other end is provided. The side contact portion 10b is pressed against the rack pin 7 and the other end side contact portion 10b is formed in a substantially linear shape so as to be along the moving direction H of the metering rack 6. Things.

According to a third aspect of the present invention, in the fuel metering device for a diesel engine according to the first or second aspect, one end of the metering rack is elastically moved toward the fuel increasing side by the starting increasing spring. It is characterized by being configured to be biased.

[0010]

According to the first aspect of the present invention, the pressing spring 10 is pressed against the rack pin 7 so as to restrict the deflection of the metering rack 6 in the movement cross direction Z. Therefore, the swinging of the fork lever 1 causes the contact surface 1a of the fork lever 1 to assume a forwardly inclined position or a rearwardly inclined position, and even if a component force is generated that pushes the rack pin 7 upward or downward, the metering rack 6 Does not occur in the movement cross direction Z. Thereby, as shown by the solid line in FIG. 3, a smooth shaft torque curve K can be drawn, the torque shortage can be eliminated, and the responsiveness of the centrifugal governor can be improved.

(B) According to the first aspect of the present invention,
It is not necessary to form the pin contact surface 1a of the fork lever 1 in a cycloidal curve as in the previously proposed example. Instead, the pressing spring 10 is pressed against the rack pin 7 to reduce the deflection of the metering rack 6 in the movement cross direction Z. Since the configuration is such that production is regulated, production costs can be reduced, and implementation is simple.

(C) According to the second aspect of the invention, one end 10a of the pressing spring 10 is fixed, the intermediate portion 10c is supported by the fulcrum pin 12, and the other end side contact portion 10b is pressed against the rack pin 7. Since the other end side contact portion 10b is formed in a substantially linear shape and extends along the moving direction H of the metering rack 6, the pressing spring 10 has a substantially linear shape within the moving range of the rack pin 7. The end contact portion 10b keeps pressing the rack pin 7 in the same posture, so that the response sensitivity of the centrifugal governor can be kept constant.

(D) According to the third aspect of the present invention, since one end of the metering rack 6 is elastically urged toward the fuel increasing side R by the starting increasing spring 3, the rack pin 7 is always elasticized by the starting increasing spring 3. By being pressed against the contact surface 1a of the fork lever 1, the backlash between the rack pin 7 and the contact surface 1a of the fork lever 1 is eliminated, and the responsiveness of the centrifugal governor can be improved.

[0014]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a centrifugal governor according to an embodiment of the present invention. 1, reference numeral 5 denotes a fuel injection pump, reference numeral 20 denotes a gear case, reference numeral 30 denotes a camshaft drive gear, and reference numeral 31 denotes a pump drive camshaft.

The centrifugal governor includes a fork lever 1 pivotally supported by a swing support shaft Q. The fork lever 1 has a two-lever type first lever 1A and a second lever 1A.
B, the governor weight 8 is operatively connected to the input portion 1C of the first lever 1A, the rack pin 7 is operatively connected to the distal end of the second lever 1B, and a governor spring is connected to the distal end of the first lever 1A. And a governor spring (not shown) is connected to adjust the tension of the governor spring with the governor lever. The fork lever 1 is swung by the tension of the governor spring and the governor force G of the governor weight 8. It is configured to move the metering rack 6 through the rack pin 7 by moving the metering rack. Reference numeral 2 in FIG. 1 indicates a torque-up device interposed between the first lever 1A and the second lever 1B.

Hereinafter, a configuration which characterizes the present invention will be described. In the present embodiment, as shown in FIG. 1, a pressing spring 10 is pressed against the rack pin 7 so as to restrict the deflection of the metering rack 6 in the movement cross direction Z. This is intended to reduce the production cost by a simple configuration and to improve the responsiveness of the centrifugal governor by eliminating the torque shortage. That is, the swinging of the fork lever 1 causes the contact surface 1a of the fork lever 1 to assume a forwardly inclined posture or a backwardly inclined posture. However, even if a component force that pushes the rack pin 7 upward or downward is generated, the pressing springs 10 By regulating the deflection of the metering rack 6 in the movement cross direction Z, a smooth shaft torque curve shown by a solid line K in FIG. 3 is drawn, and the lack of torque is eliminated to improve the responsiveness of the centrifugal governor. is there.

The pressing spring 10 has one end 10a fixed with a screw 11 and the intermediate portion 10c supported by a fulcrum pin 12.
The other end side contact portion 10b is pressed and contacted with the rack pin 7 upward, and the other end side contact portion 10b is formed in a substantially linear shape so as to extend along the moving direction H of the measuring rack 6. is there. This is because the pressing spring 10
Is intended to maintain the response sensitivity of the centrifugal governor constant by keeping the substantially linear other end side contact portion 10b pressing the rack pin 7 in the same posture.

In this embodiment, one end of the metering rack 6 is elastically urged toward the fuel increasing side R by the starting increasing spring 3. As a result, the rack pin 7 is always pressed against the contact surface 1a of the fork lever 1 by the resilient force of the start increasing spring 3,
The backlash between the rack pin 7 and the contact surface 1a of the fork lever 1 is eliminated to improve the responsiveness of the centrifugal governor. Note that reference numeral 1 in FIG.
Reference numeral 4 denotes a spring accommodating case composed of a case body 14a and a case lid 14b. The case body 14a provided on the governor wall 15 so as to be able to advance and retreat is provided with a spring for increasing the starting spring 3 and one end of the metering rack 6. A spring contacting member 16 for contacting is accommodated, and an adjusting screw 17 for adjusting the elasticity of the starting increasing spring 3 is screwed to the other case cover 14b.

FIG. 2 is a longitudinal sectional view of a main part of the engine stopping device. As shown in FIG. 2, the engine stop device includes a stop solenoid 21, an external fitting rod 23 externally fitted to an output rod 22 of the stop solenoid 21, and a base flange 24 of the external fitting rod 23. An operation lever 26 and an operation handle 27 for manually operating the external fitting rod 23, and a winding return spring 28 for returning the operation lever 26 and the operation handle 27 to the stop release position, the output rod 22 of the stop solenoid 21 or the above operation External fitting rod 2 with lever 26
3 is protruded, and the other end of the metering rack 6 is pushed into the fuel reduction side L at the tip end 23a to stop the engine.

A cushioning material 26 made of rubber or the like is inserted into the inside of the fitting hole 25 of the outer fitting rod 23 to absorb a shock when the output rod 22 projects. This is intended to prevent a control sleeve (not shown) of the fuel injection pump 5 from being damaged by impact. Reference numeral 18 in FIG. 2 denotes a fuel limiting pin for restricting the first lever 1A to a position corresponding to full load (4/4).

The present invention is not limited to the above embodiment, but can be implemented with appropriate modifications as described below. For example, a one-lever fork lever is used instead of the two-lever type. Further, the pressing spring 10 is connected to the rack pin 7.
Instead of the one that presses upward, the one that presses downward is used.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a centrifugal governor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the engine stop device according to the embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a rotation speed of an engine and a shaft torque.

FIG. 4A is an essential part extraction view of a centrifugal governor, and FIG. 4B is an enlarged view of a principal part showing a state in which a fork lever contact surface contacts a rack pin in a forwardly inclined posture. FIG. 4 (C) is an enlarged view of a main part showing a state in which the fork lever contact surface is in contact with the rack pin in a rearwardly inclined posture, and FIG. 4 (D) is an engagement state between the control pinion of the fuel injection pump and the metering rack. FIG.

FIG. 5 is an enlarged view of a main part of a fork lever according to a previously proposed example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fork lever, 3 ... Start increasing spring, 4 ... Governor spring, 5 ... Fuel injection pump, 6 ... Metering rack, 7 ...
Rack pin, 8: governor weight, 10: pressing spring, 1
0a: One end of the pressing spring, 10b: Contact portion at the other end of the pressing spring, 10c: Intermediate portion of the pressing spring, 12: Support pin, G ...
Governor force, H: moving direction of metering rack, R: fuel increasing side, S: tension of governor spring, Z: moving crossing direction of metering rack.

Claims (3)

[Claims] 1. A fork lever (1) is interlockedly connected to a metering rack (6) of a fuel injection pump (5) via a rack pin (7), and a tension (S) of a governor spring (4) and a governor weight ( The fork lever (1) is swung by the governor force (G) of 8), and the rack pin (7)
In a fuel metering device for a diesel engine, the metering rack (6) is configured to move the metering rack (6) through a pressurizing spring (10) against the rack pin (7). 6) A fuel metering device for a diesel engine, which is configured to restrict the swing in the movement cross direction (Z). 2. The fuel metering device for a diesel engine according to claim 1, wherein one end (10a) of the pressing spring (10) is fixed, and an intermediate portion (10c) is supported by a fulcrum pin (12). The end side contact portion (10b) is pressed against the rack pin (7), and the other end side contact portion (10b) is formed in a substantially straight line so as to move in the moving direction (H A fuel metering device for a diesel engine according to (1). 3. The fuel metering device for a diesel engine according to claim 1, wherein one end of the metering rack (6) is resiliently moved toward a fuel increasing side (R) by a starting increasing spring (3). A fuel metering device for a diesel engine, wherein the fuel metering device is configured to be biased.