JPH0622562U - Torsion viscous damper mounting structure for fuel injection pump - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object to provide an effective structure for mounting a viscous damper to a drive system of a fuel injection pump. [Structure] A timer housing 15 of a timer 11 is directly connected to a drive shaft 13 via a coupling device 14, and extends from the end face peripheral portion of the timer housing 15 on the coupling device 14 coupling side in parallel with the central axis of the timer 11 to form a coupling. A case portion 38, which has an annular shape surrounding the device 14 and forms a cylindrical space of the torsional viscous damper 12, is integrally molded with the timer housing 15.
A cover 39 for sealing the cylindrical space of the case portion 38 is provided, and the thrust bearing 4 is provided inside the sealed cylindrical space.
0 and the journal bearing 41, the inertia ring 42 rotatably supported by the journal bearing 41 is housed, and the cylindrical space is filled with silicone oil 43.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torsional viscous damper that is interposed in a drive system of a fuel injection pump to reduce torsional vibrations, torque fluctuations, etc. of the drive system, and more particularly to a technique related to its mounting structure.

[0002]

[Prior art]

 2. Description of the Related Art In recent years, demands for higher output, lower fuel consumption, and longer life have been increasing in diesel engines for small vehicles for long-distance transportation. In particular, due to the trend toward higher output, the average effective pressure increased, and the vibration torque to the crankshaft increased.

As a result, the adoption of a torsional viscous damper (hereinafter simply referred to as a viscous damper) has been considered effective for the purpose of reducing the torsional vibration of the crankshaft caused by the gas pressure and inertial force in the cylinder. This viscous damper is composed of a disk-shaped inertial mass portion and a fixed portion to the crankshaft, and a high-viscosity silicone oil or the like as a viscoelastic body is interposed between the viscous damper and the crankshaft. It is usually attached to the tip of the.

As shown in FIG. 4, a typical structure of a viscous damper forms a cylindrical closed space by a case 1 and a cover 2, and a thrust bearing 3 and a journal bearing 4 are provided inside the closed space. The inertial ring 5 which is positioned by and is rotatably supported is housed therein, and high-viscosity silicone oil 6 is filled inside the closed space.

The case 1 and the cover 2 are integrated with each other by sandwiching a sealing material, press-fitting and caulking. The case 1 is fixed to the crankshaft with bolts, and the connection between the case 1 and the inertia ring 5 is made only through the silicone oil 6. Under the condition that there is no torsional vibration, the case 1 and the inertia ring 5 rotate as if they were an integral unit. As the engine speed changes to a point where the torsional vibration is excited, the crankshaft, that is, the case 1 fixed to the crankshaft, exhibits a phenomenon in which the torsional vibration is added on the main rotation. Since the inertia ring 5 tries to keep a constant rotation due to its own inertia, a relative rotational vibration change occurs between the case 1 and the inertia ring 5, so that the silicone oil 6 receives shear force. The vibration energy of the crankshaft is replaced by heat energy, and the vibration of the crankshaft is absorbed.

The viscous damper is significantly different from other rubber dampers and the like in that there is no elastic coupling portion between the inertia ring 5 and the case 1. Therefore, it can be said that the damper does not require tuning. Whereas a damper that needs to be tuned creates another resonance point, this type of viscous damper is advantageous in that it does not cause additional resonance.

[0007]

[Problems to be solved by the device]

In recent years, are being enhanced exhaust gas regulations for diesel engines, N O _X, black smoke and particulate measures are urgently. As a countermeasure, it has been proposed to promote atomization of fuel in order to improve the combustion efficiency of diesel engines.

Therefore, the injection pressure is increased in the fuel injection pump to inject the fuel at high pressure. However, as a result of increasing the injection pressure in the fuel injection pump in this way, the torsional vibration and torque fluctuation of the drive system of the fuel injection pump increase, and the gear noise becomes noticeable. In particular, the peak torque reaches about 2.5 times the steady torque.

In order to suppress the increase of the torsional vibration and the torque fluctuation of the drive system of the fuel injection pump, it is necessary to increase the size of the support and the bearing and the size of the drive system. It does not seem to be increasing or increasing in size. Therefore, by installing a viscous damper, which is provided exclusively for reducing the torsional vibration of the crankshaft, in the drive system of the fuel injection pump, the torsional vibration and torque fluctuation of the drive system of the fuel injection pump are reduced. It was discovered.

However, in the past, there has been no proposal as to how to effectively dispose the viscous damper in the drive system of the fuel injection pump. There was a long-awaited proposal for the mounting structure. In view of the above conventional problems, it is an object of the present invention to provide an effective structure for mounting a viscous damper on a drive system of a fuel injection pump.

[0011]

[Means for Solving the Problems]

 Therefore, in the torsional viscous damper mounting structure for the fuel injection pump of the present invention, the torsional viscous damper is interposed at the connecting portion between the drive shaft to which the engine driving force is transmitted and the camshaft of the fuel injection pump. A structure for attaching to a timer for controlling fuel injection timing, in which the timer housing of the timer is directly connected to a drive shaft via a coupling device, and the center of the timer is measured from an end face peripheral portion of the timer housing on the coupling device connection side. A case portion forming a cylindrical space of the torsional viscous damper that extends in parallel with the axis and surrounds the coupling device is integrally molded with the timer housing, and the cylindrical space of the case portion is formed. A cover for enclosing the cylinder is installed, and thrust and journal bearings are placed inside the enclosed cylindrical space. It is positioned by grayed, while accommodating the support inertial-ring in a rotatable state, filled with highly viscous liquid within said cylindrical space.

[0012]

[Action]

 In such a structure, the case and the inertia ring of the viscous damper rotate as if they were an integral unit in the absence of torsional vibration. As the number of revolutions of the fuel injection pump changes to a point where it excites torsional vibrations, torsional vibrations are added to the main rotation of the drive shaft and cam shafts, that is, the case parts fixed to these shafts. The phenomenon as described above is exhibited. Since the inertia ring tries to keep a constant rotation due to its own inertia, a relative rotational vibration change occurs between the case part and the inertia ring. It is replaced with thermal energy, and vibrations of the drive shaft and camshaft are absorbed, and torque fluctuations are dampened and alleviated.

[0013]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, the drive system of the fuel injection pump 10 is provided with a fuel injection pump drive gear portion (not shown), and the fuel injection timing is provided between the fuel injection pump drive gear portion of the drive system and the fuel injection pump 10. A control timer 11 is interposed, and a torsional viscous damper (hereinafter, simply referred to as a viscous damper) 12, which is the object of the present invention, is integrally provided on the timer 11.

A structure in which the viscous damper 12 is integrally provided with the timer 11 will be described. First, the structure and operation of the timer 11 will be described with reference to FIGS. A timer housing 15 is directly connected to a drive shaft 13 guided from the fuel injection pump drive gear portion via a coupling device 14 described later. The flyweight 16 is incorporated and held in the press-fitting pin 17 of the timer housing 15. The tip of the cam shaft 19 of the fuel injection pump 10 is passed through the attachment hole 18a of the attachment boss 18A of the flange 18, and the taper shaft 19A provided on the base side of the tip of the cam shaft 19 is attached to the attachment hole 18a. It is fitted to the inner peripheral surface of the hole 18a. A key (not shown) is fitted into this fitting surface.

A male screw portion (not shown) is formed at the end of the cam shaft 19 projecting from the mounting hole 18a, and the nut 20 is fitted to this male screw portion to allow the cam shaft 19 and the mounting boss portion 18A to be fitted. And are concluded. A spring washer 21 is interposed between the nut 20 and the end surface of the mounting boss 18A. In this way, a curved surface 18B is formed on the inner surface of the flange 18 connected to the camshaft 19 of the fuel injection pump 10, and the curved surface 18B is fitted into the press-fitting pin 22 of the flyweight 16 described above. Roller 23 is in contact.

The surface of the flange 18 and the half-moon type spring seat 24 fitted to the press-fitting pin 17 of the timer housing 15 penetrating the flyweight 16 are opposed to each other, and the timer spring 25 having a setting force is mounted between them. Has been. A cover 26 is provided on the surface of the timer housing 15 on the flange 18 side, and the cover 26 is fastened to the press-fitting pin 17 by a bolt 27.

FIG. 3A shows a state in which the flyweight 16 does not have a centrifugal force, and the flyweight 16 does not have a centrifugal force. With the press-fitting pin 17 (point B) of the timer housing 15 as a fulcrum, the timer spring 25 having a setting force The press-fitting pin 22 (point A) of the flyweight 16 is pulled and comes into contact with the curved surface 18B of the flange 18. Once the engine has started, the timer 11 rotates clockwise, and the press-fitting pin 22 (point A) of the flyweight 16 is connected via the press-fitting pin 17 (point B) of the timer housing 15 directly connected to the drive shaft 13. The curved surface 18B of the flange 18 is pushed to rotate the fuel injection pump 10. Then, when the centrifugal force of the flyweight 16 is inferior to the setting force of the timer spring 25, the state of FIG. 3 (A) is continued. Further, when the rotation of the fuel injection pump 10 rises and the centrifugal force and the set force are balanced, the advance angle starts, and the advance angle advances as the rotation increases thereafter.

FIG. 3B shows the maximum advance angle. When the centrifugal force gradually increases, the flyweight 16 contracts the timer spring 25 around the press-fitting pin 17 (point B) of the timer housing 15 as a fulcrum, and moves the flange 18 in the rotational direction while opening outward (Fig. 3). (Movement from dotted line to solid line in (B)).

That is, the flange 18 rotates in the rotational direction by the amount of contraction of the timer spring 25, and a phase shift occurs between the drive shaft 13 and the cam shaft 19 of the fuel injection pump 10. Correct the delay of. When the rotation of the fuel injection pump 10 rises and reaches the maximum advancing angle, the flyweight 16 hits the inner wall of the timer housing 15, and the advancing angle is not performed even if it rotates further.

The coupling device 14 that directly connects the timer housing 15 of the timer 11 to the drive shaft 13 is configured as follows. A first laminate type coupling 28 formed by stacking a plurality of thin plates and fastened to the drive shaft 13, an arm joint 29 to which the coupling 28 is fastened, and a second to which the arm joint 29 is fastened. Laminating type coupling 30 is provided.

A substantially cylindrical joint 31 is fixedly attached to the end of the drive shaft 13 with bolts 32. On both sides of the outer peripheral surface of the joint 31, a pair of mounting plate portions 31A extending along a surface orthogonal to the central axis thereof are formed. An opening is formed in the central portion of the first laminate type coupling 28, and two opposite portions of the peripheral portion are fastened and fixed to the pair of mounting plate portions 31A by bolts 33 and nuts 34, respectively. In this case, a part of the joint 31 is passed through the opening of the first laminated coupling 30.

An opening is formed in the central portion of the arm joint 29, and a pair of mounting plate portions 29 A extending along a plane orthogonal to the central axis of the opening are formed at opposite sides of the opening forming portion. A pair of mounting plate portions 29B extending along a surface orthogonal to the central axis of the opening is formed at both side portions of the opening forming portion which face each other in a direction orthogonal to the both side portions. That is, the arm joint 29 is formed such that two sets of a pair of mounting plate portions 29A and 29B are provided, and these mounting plate portions 29A and 29B have a cross shape.

Female screw holes for bolts are formed at the tips of the mounting plate portions 29A and 29B, respectively. The two portions of the peripheral portion of the first laminate type coupling 28, which face each other in the direction orthogonal to the fastening portion by the bolts 33, are fastened by the bolts 35 to one of the pair of mounting plate portions of the arm joint 29. 29A are respectively fastened and fixed. Two opposing portions of the peripheral portion of the second laminate type coupling 30 are respectively fastened and fixed to the other pair of mounting plate portions 29B of the arm joint 29 by bolts 36.

The head of the bolt 36 is inserted into a groove 37 formed in the end wall of the timer housing 15. On the other hand, two portions of the peripheral portion of the second laminate type coupling 30, which face each other in the direction orthogonal to the fastening portion by the bolt 36, are fastened and fixed by the bolt 38 to the circumferential portion of the end wall of the timer housing 15, respectively. To be done. .

Here, a cylindrical shape of the viscous damper 12 is formed so as to extend in parallel with the central axis of the timer 11 from the peripheral portion of the end surface of the timer housing 15 on the coupling device 14 coupling side and surround the periphery of the coupling device 14. A case portion 38 forming a space is integrally formed with the timer housing 15. Further, a cover 39 for sealing the cylindrical space of the case portion 38 is provided.

The viscous damper 12 is rotatably supported by a resin-made thrust bearing 40 and a journal bearing 41, which are positioned inside a cylindrical closed space formed by the case portion 38 and the cover 39. The inertia ring 42 is accommodated, and the sealed space is filled with silicone oil 43 as a high-viscosity liquid.

In such a configuration, the case portion 38 and the inertia ring 42 of the viscous damper 12 rotate as if they were an integral unit under the condition that there is no torsional vibration. As the rotational speed of the fuel injection pump 10 changes to a point at which torsional vibration is excited, the drive shaft 13 and the cam shaft 19, that is, the case portion 38 fixed to these, adds torsional vibration to the main rotation. The phenomenon as described above is exhibited. Since the inertia ring 42 tries to keep a constant rotation due to its own inertia, a relative rotational vibration change occurs between the case portion 38 and the inertia ring 42, so that the silicone oil 43 is sheared. In response to this, the vibration energy is replaced with heat energy, the vibration of the drive shaft 13 and the cam shaft 19 is absorbed, and the torque fluctuation is attenuated and alleviated.

According to this configuration, in the fuel injection pump 10 having a high injection pressure, the torsional vibration and torque fluctuation of the drive system can be effectively reduced, the generation of gear noise can be suppressed, and the support and the bearing can be added and driven. Since it is not necessary to increase the size of the system, there is no increase in weight or size. In particular, according to the above configuration, the viscous damper 12 can be integrally formed with the timer 11 by integrally molding the case portion 38 with the timer housing 15. Therefore, the viscous damper 12 needs to be provided separately from the timer 11. In addition, there is no need for a mounting tool or the like for mounting the viscous damper 12, and the work for mounting the viscous damper 12 is also unnecessary. Simply changing the shape of the timer housing 15 can reduce the manufacturing cost. it can.

Since the case portion 38 of the viscous damper 12 is formed so as to surround the coupling device 14, even if the viscous damper 12 is additionally provided in the drive system of the fuel injection pump 10, the fuel injection pump 10 can be driven. The length of the system does not become long, and the drive system can be kept compact as before. In this embodiment, the laminated couplings 28 and 30 are used as the coupling device for connecting the viscous damper 12 and the timer 11, and the drive side (drive shaft 13) and the driven side (timer housing 15). Since the fulcrums of) are attached at right angles to each other, the reversibility of the thin plates of the laminated couplings 28, 30 acts like a universal joint of the propeller shaft, and the rotation of the drive shaft 13 is smoothly transferred to the timer housing 15. Can be transmitted to.

As described above, the present invention has been described with reference to the specific embodiments, but the present invention is not limited to this, and a person skilled in the art can apply the present invention to the present invention. It should be noted that various changes and modifications can be made without departing from the scope of the attached utility model registration request.

[0031]

[Effect of device]

 As described above, according to the torsional viscous damper mounting structure for a fuel injection pump of the present invention, the timer housing of the timer is directly connected to the drive shaft through the coupling device, and the coupling device of the timer housing is connected. The case that forms a cylindrical space for the torsional viscous damper that extends parallel to the central axis of the timer from the side end surface and that surrounds the coupling device is integrally molded with the timer housing. Since the cover that seals the cylindrical space of is used, the torsional vibration and torque fluctuation of the drive system in the fuel injection pump can be effectively reduced, the generation of gear noise can be suppressed, and the adoption of the laminated coupling The rotation of the drive shaft can be smoothly transmitted to the viscous damper case. Furthermore, since it is not necessary to install a viscous damper separately from the timer, the number of parts can be reduced, installation workability can be improved, manufacturing costs can be kept low, and the drive system remains compact. There is an advantage that it can be suppressed to a large practical effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a torsional viscous damper mounting structure for a fuel injection pump according to the present invention.

FIG. 2 is an assembled perspective view showing a configuration of a timer according to the embodiment.

FIG. 3 is an internal structure diagram showing the operation of the timer described above.

FIG. 4 is a perspective view showing a structure of a typical torsional viscous damper.

[Explanation of symbols]

 10 Fuel Injection Pump 11 Timer 12 Viscous Damper 13 Drive Shaft 14 Coupling Device 15 Timer Housing 38 Case Part 39 Cover 40 Thrust Bearing 41 Journal Bearing 42 Inertial Ring 43 Silicone Oil

Claims (1)

[Scope of utility model registration request] 1. A structure for attaching a torsional viscous damper to a timer for controlling fuel injection timing, which is provided in a connecting portion between a drive shaft to which engine driving force is transmitted and a cam shaft of a fuel injection pump, the structure comprising: An annular ring that directly connects the timer housing of the timer to a drive shaft via a coupling device, extends from an end surface peripheral portion of the timer housing on the coupling device connection side in parallel with the central axis of the timer, and surrounds the periphery of the coupling device. The case portion forming the cylindrical space of the torsional viscous damper is integrally formed with the timer housing, and a cover for sealing the cylindrical space of the case portion is provided, and the thrust and the thrust are provided inside the sealed cylindrical space. Holds an inertial ring positioned by journal bearings and rotatably supported A torsional viscous damper mounting structure for a fuel injection pump, characterized in that the cylindrical space is filled with a high-viscosity liquid.