JPH021463Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an oil leak prevention device for a hydraulic timer, and more particularly to an oil leak prevention device for a hydraulic timer that prevents oil from leaking to the outside of an input side disk that drives the hydraulic timer.

In the past, the fuel injection timing of diesel engines was generally adjusted using a flyweight timer whose movement amount varied depending on the engine speed, but in recent years, hydraulic pressure has been used for this timer. A system called a hydraulic timer is beginning to be adopted.

Such a hydraulic timer device may be formed integrally with the driven side shaft 1, for example, as shown in the side sectional view of FIG. 1 and FIG. , or a first eccentric cam 3 fitted within a disc 2 fixed to rotate together.
and a second eccentric cam 4 fitted to the first eccentric cam 3.

The disk 2 and these first and second eccentric cams 3
and 4 are shown in the upper half of FIG. A pin 8 fixed to the piston 7 is engaged.

The piston 7 is housed in a cylinder 9 rotatably attached to the driven shaft, and is biased by a spring 10.

The driven shaft 1 is connected to a camshaft of a fuel injection pump (not shown), and pressurized lubricating oil O is supplied from a hydraulic device 14 into a cylinder 9 located on the outer periphery of the driven shaft 1. This hydraulic system 14 pressurizes lubricating oil O in an oil tank 15 with a pump 17 and sends the oil to an oil pipe 13 having a throttle 11. While detecting N and load L, the controller 12
The injection timing of the fuel injection pump can be changed using the pressure regulating valve 16.

That is, when the piston 7 moves in the direction A in the figure, it is operated by the hydraulic force of the lubricating oil O, and when it moves in the direction B, it is operated by the return spring 10.
It is designed to be operated by the urging force of
When the piston 7 presses the spring 10 in the direction of arrow A due to hydraulic pressure, the pin 8 moves to the position shown by the broken line, thereby rotating the first eccentric cam, and thereby the second eccentric cam 4 and pin 6 move to the position shown in FIG. The driven shaft 1 is advanced by θ with respect to the drive shaft disc 5.

FIG. 3 is a partial sectional view showing the specific structure of a conventional hydraulic timer 20 that operates as described above.
Parts that are the same as the apparatus of FIGS. 1 and 2 are numbered the same.

Similar to the hydraulic timer device shown in FIGS. 1 and 2, this device also has a disk 2 attached to the driven shaft 1, and a first
The eccentric cam 3 and the second eccentric cam 4 are fitted together in the same manner as described above. 5 is a drive disk, 6 is a pin that connects the drive disk 5 and the second eccentric cam 4,
The first eccentric cam 3 and the piston 7 sliding inside the cylinder 9 provided on the side of the fuel injection pump are connected to each other via a plate 24 biased by a spring (not shown) installed on the side surface of the cylinder 9. pin 8
a and pin 8b.

The piston device, cam device, etc. are integrally housed in a timer housing 21, and the housing 21 rotates while maintaining an advance angle as the drive disk 5 rotates. Reference numeral 19 denotes a pulse gear plate attached to the input side of the housing 21 for detecting injection timing.

In the hydraulic timer 20 configured in this manner, the lubricating oil O is fed into the hollow shaft 22 fixed to the center of the disk 2 through a predetermined path through the oil supply hole penetrating the hollow shaft 22. 23 into the cylinder 9 and move the piston 7. Reference numeral 25 denotes a plug having a wide flange portion, and the threaded portion of this plug 25 is screwed onto the inner diameter of the hollow shaft 22, and the flange portion contacts the end surface of the hollow shaft 22, so that the lubricating oil O is drawn into the hollow shaft. Although the lubricating oil O in the hollow shaft 22 is prevented from flowing out from the end face of the shaft 22, the lubricating oil O in the hollow shaft 22 is leaked from the threaded portion 25a of the plug 25 to the hollow shaft 2
The interface 27 between the drive disk 5 and the hollow shaft 22 flows out through the oil filling hole 26 of No. 2 and rotates relative to each other.
Lubricate.

In other words, the small diameter hole 1 is located in the center of the drive disk 5.
A stepped hole 18 consisting of a large diameter hole 18a and a large diameter hole 18b is provided, and by rotatably inserting the outer diameter of the hollow shaft 22 into this small diameter hole 18a, the hollow shaft 22 and the small diameter hole 18a of the drive disk 5 are connected. The hollow shaft 22 on the disc 5 side rotates relative to the drive disk 5 while adjusting the advance angle, and the drive disk 5 is connected to the end of the hollow shaft 22. The inner surface of the flange portion of the plug 25, which abuts on the hollow shaft 22 and has a large diameter, is positioned so as to be rotatable relative to the hollow shaft 22. 28 is the large diameter hole 18b
An oil seal rubber attached to the inner surface of the plug 25 prevents lubricating oil O leaking from the interface 27 from entering the plug 25.
The outer periphery of the flange part and the large diameter hole 18 of the drive disk
It is provided so that it does not leak to the outside from between the

That is, conventionally, it is necessary to position the drive disk 5 so that it can rotate freely relative to the hollow shaft 22 by the flange portion of the plug 25 screwed onto the shaft end of the hollow shaft 22. Since the drive disk 5 is provided with a large diameter hole 18b as an insertion hole for insertion from the 5 side to the shaft end of the hollow shaft 22, an oil seal 28 is provided to prevent oil from leaking from this large diameter hole 18b. It was necessary to set it up.

However, in the conventional hydraulic timer 20 configured as described above, the oil seal rubber 2
8, and oil leakage from the oil seal rubber 28 due to lack of followability when the disk 2 and disk 5 rotate eccentrically, the lubricating oil O is leaked to the input side of the drive disk 5. There is a problem with the leakage.

This idea was devised to solve the problem in view of the conventional situation mentioned above, and eliminates the oil seal rubber provided between the outer diameter of the flange part of the plug provided on the hollow shaft and the drive disk. It is an object of the present invention to provide an excellent oil leakage prevention device for a hydraulic timer that can prevent lubricating oil from leaking to the outside due to the oil seal rubber.

To achieve the above object, the present invention provides a hydraulic timer for adjusting the advance angle of a camshaft of a fuel injection pump using a hydraulic piston. The small diameter hole of the disk is inserted into the hollow shaft on the driven side that communicates with the piston, and a blind plug with a flange inserted through the large diameter hole is screwed onto the end of the hollow shaft, so that the disk can be rotated relative to each other. position,
It is characterized in that the large diameter hole is sealed by a blind plug that does not come into contact with the flanged blind plug.

Embodiments of this invention will be described below with reference to the drawings.

FIG. 4 shows a hydraulic timer 20' of this invention, showing the same section as the conventional hydraulic timer 20 of FIG. 3.
3, in which the same parts as in FIG. 3 are given the same numbers and their explanations will be omitted.

In this invention, first, the hollow shaft 22 which is the driven side
A blind plug 30 inserted through the large diameter hole 18b is screwed onto the end of the drive disk 5 side. In other words, this blind plug 30 is configured as a flanged plug consisting of a flange portion 31 and a threaded portion 32 as shown in FIG. The plug 30 is configured to have a large diameter, and an engagement recess 33 is provided in the center of the flange portion 31 for rotating the plug 30 with a tool and screwing it onto the hollow shaft 22. The threaded portion 32 of this plug 30 is a coarse thread so that the lubricating oil O can lubricate the interface 27 between the hollow shaft 22 and the drive disk 5 through the oiling hole 26 through the threaded portion 32. Furthermore, the blind plug 30 is screwed onto the end of the hollow shaft 22 in a closed state, and its flange portion 31 positions the drive disk 5 relative to the hollow shaft 22 so as to be rotatable.

Next, in this invention, a blind plug 40, which is completely separate from the plug 30, is prepared, and this is screwed into the large diameter hole 18b of the stepped hole 18 provided in the disk 5. As shown in FIG. 6, this plug 40 has a threaded portion 42 on the side peripheral surface of a main body 41, and a mounting nut 43 protruding from the input side outer surface, so that this plug 40 can be easily attached with a spanner, wrench, etc. It can be screwed into the large diameter hole 18b. At this time, the threaded portion should be completely sealed using a sealant or the like. Further, this plug 40 is attached to the plug 30 in a screwed state.
Since it is configured so that it does not come into pressure contact with the disk 2,
It does not interfere with the movement of the

In the hydraulic timer oil leak prevention device of this invention constructed in this way, the lubricating oil does not leak to the outside of the hydraulic timer, and moreover, the oil seal uses a plug that does not deteriorate or deform. Oil leakage is completely prevented against aging and vibration.

As explained above, the present invention provides a hydraulic timer for adjusting the advance angle of a camshaft of a fuel injection pump using a hydraulic piston, in which a small diameter hole and a large diameter hole are provided in the center of a drive disk that drives the hydraulic timer. The small-diameter hole of the disk is fitted into the hollow shaft on the driven side that communicates with the piston, and a blind plug with a flange inserted through the large-diameter hole is screwed onto the end of the hollow shaft, so that the disk can be rotated relative to each other. The large-diameter hole was sealed with a blind plug that does not contact the flanged blind plug, and then a drive disk with a small-diameter hole inserted into the hollow shaft that communicates with the hydraulic piston is inserted into the large-diameter hole at the end of this hollow shaft. By screwing together the flanged blind plug inserted through the hole, it is possible to position it so that it can rotate freely.

Furthermore, the large diameter hole provided in this drive disk for inserting the flanged blind plug is sealed with a blind plug that does not come into contact with the flanged blind plug, so there is no need for an oil seal to be provided in the large diameter hole as in the past. Therefore, unlike oil seals, there is no deterioration over time, and there is no need to worry about oil leakage due to vibration, and the oil leakage prevention of the hydraulic timer is completely reliable.

[Brief explanation of the drawing]

Fig. 1 is a schematic side sectional view of a conventional hydraulic timer, Fig. 2 is a schematic front sectional view taken along the line C-C in Fig. 1, and Fig.
The figure is a partial cross-sectional view showing the overall structure of a conventional hydraulic timer device, and FIG. 4 is a cross-sectional view of an oil leak prevention device for a hydraulic timer of this invention, showing the same section as the conventional hydraulic timer shown in FIG. 5 and 6 are perspective views of the plug of FIG. 4, respectively. 1... Driven side shaft, 2... Disc, 5... Disc, 6, 8, 8a, 8b... Pin, 7... Piston, 9... Cylinder, 18... Stepped hole, 18a...
...Small diameter hole, 18b...Large diameter hole, 20...Conventional hydraulic timer, 20'...Hydraulic timer of this invention, 2
2...Hollow shaft, 23...Oil filling hole, 25...Plug, 26...Oil filling hole, 27...Boundary surface, 28...
Oil seal rubber, 30, 40...Plug, 31
...Flange portion, 32...Threaded portion, 33...Engagement recess, 42...Threaded portion, 43...Mounting nut.

Claims (1)

[Scope of utility model registration request] In a hydraulic timer that adjusts the advance angle of a camshaft of a fuel injection pump by a hydraulic piston, a drive disk that drives the hydraulic timer has a small diameter hole and a large diameter hole in the center, and a hollow shaft on the driven side that communicates with the piston. A blind plug with a flange, which is inserted through the large diameter hole, is screwed into the end of the hollow shaft to position the disk so that it can rotate freely, and the large diameter hole is inserted into the flange. An oil leak prevention device for a hydraulic timer that is sealed by a blind plug that does not contact the attached blind plug.