JPH02298611A - Lubricating structure for roller tappet - Google Patents

Abstract

PURPOSE:To sufficiently lubricate surfaces which make contact with each other by pressurizing oil between a tapper hole in a tapper body and a tapper body fitted in the tapper hole, fed from a cylinder chamber so as to feed the oil under pressure between the surfaces of a roller and a pin which make contact with each other during ascent of a roller tappet. CONSTITUTION:A tappet body 30 having a large diameter lower end part 32a is fitted slidably in a tapper hole 20 formed in a cylinder body 1 and having a large diameter lower end part 21 so that a cylinder chamber 22 is defined between the lower end parts 21, 32a. Further, a roller 5 is rotatably held by means of a pin 6 in a recess 33 formed in the lower end part 32 of the tappet body 30, and is made into contact with a cam 7 so that the tappet body 30 and a push rod 4 are moved vertically. Further, an oil passage 81 communicated with the bottom part 31 of the tappet body 30 and an oil passage 81 communicated with the cylinder chamber 22 are formed in the tappet body 30. When the tappet body ascends, the hydraulic pressure in the cylinder chamber 22 is increased so as to feed hydraulic oil from the cylinder chamber 22 between the surfaces of the roller 5 and the pin 6 which make contact with each other under pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubrication structure for a roller tappet in a valve train of an internal combustion engine.

[Prior Art] As shown in Fig. 1, the lubrication structure of a roller tappet in a conventional valve train of an internal combustion engine is based on a tappet body 3 that is slidably fitted into a tappet hole of a cylinder body 1 of an internal combustion engine. The bottom part 31 receives the lower end of the bushing rod 4, and the roller 5 is rotatably supported by a pin 6 in a recess 33 formed in the lower end part 32 of the tappet body 3.
is in constant contact with a cam 7 driven by a crankshaft (not shown), and is configured to move the tappet body 3 and bushing rod 4 up and down under the action of the cam 7.

In order to lubricate the contact surface between the roller 5 and the pin 6, an oil passage 8 is provided at the lower end 32 of the tappet body 3 and communicates with the bottom 31, and the pin 6 is provided with an oil passage 8 communicating with the oil passage 8 around the outer circumference of the pin. An oil supply passage 9 that opens on the surface is provided.

In a roller tappet constructed as described above.

The oil accumulated on the bottom 31 of the tappet body 3 naturally flows down the oil passage 8 and is guided to the oil supply passage 9 of the pin 6, and is supplied between the contact surfaces of the roller 5 and the pin 6.

[Problems to be Solved by the Invention] However, while the conventional roller tappet lubrication system such as the "double tappet" has a simple structure and is easy to implement, There is a problem in that the oil supply is not always sufficient, and abnormal wear phenomena often occur between the contact surfaces due to insufficient oil supply.

In addition, in the roller tappet disclosed in Japanese Utility Model Application Publication No. 57-139615, an oil passage communicating from the bottom of the tappet body to a recess for installing a roller at the lower end is filled with oil, and the oil flowing down the oil passage is brought into contact with the roller and pin. Although the tappet is supplied between the surfaces, this method may also cause the same problems as the conventional roller tappet shown in FIG. 1 described above.

Furthermore, it is conceivable to adopt a so-called forced lubrication system in which high-pressure oil is supplied from an oil pump to the oil passage 8 and the pin oil supply passage 9; Since this method requires several design changes, the structure becomes complicated, and it is difficult to adopt it from both manufacturing and economical standpoints.

The present invention was invented in view of the above-mentioned conventional roller tappet, and when the roller tappet rises due to the pushing up action of the cam, oil accumulates in the cylinder chamber formed by the lower end of the tappet hole and the lower end of the tappet body. By pressurizing
To provide a lubrication structure for a roller tappet in which lubricant is force-fed between the contact surfaces of a roller and a pin to lubricate the contact surfaces, and prevent abnormal wear from occurring due to insufficient lubrication between the contact surfaces. The purpose is to

[Means for Solving the Problems] In order to achieve the above object, the roller tappet lubrication structure of the present invention provides a roller tappet lubrication structure in which a roller is rotated through a tappet hole formed in a cylinder body and whose lower end has a large diameter. A tappet body having a large diameter lower end freely supported by a pin is slidably fitted, a cylinder chamber defined by the lower end of the tappet body is provided at the lower end of the tappet hole, and the cylinder chamber is defined by the lower end of the tappet body. Oil passages are formed in the tappet body to communicate the chamber with the bottom of the oil reservoir of the tappet body and the pin oil supply passage, respectively.

[Function] In the roller tappet lubrication structure configured as described above, when the tappet body 30 is at rest, the oil accumulated on the bottom 31 of the tappet body 30 naturally flows down from the oil passage 81, and the tappet body When the oil 30 is lowered, the oil is supplied to the cylinder chamber 22 via the oil supply path 91 and the oil path 81 due to the suction effect of the negative pressure generated in the cylinder chamber 22 .

Next, when the tappet main body 30 rises as the roller 5 receives the pushing up action of the cam 7, the volume of the cylinder 22 is reduced by the large-diameter lower end 32a of the tappet 30, and the oil pressure in the cylinder chamber 22 increases.

Therefore, the high pressure oil flows through the oil path 82. The oil is fed through the oil supply path of the pin 6 to the contact surface between the roller 5 and the pin 6.

In this way, each time the tappet body 3o rises due to the pushing up action of the cam 7, high-pressure oil is generated in the cylinder 22, and is supplied between the high-pressure oil roller 5 and the pin 6. Sufficient lubrication is provided, and abnormal wear phenomena are prevented from occurring.

In addition, when the tappet body 30 is lowered, the cylinder generates negative pressure as its volume increases and sucks oil from the bottom 31, so it also flows through the oil supply path 91 and between the contact surface with the roller 5 pin 6. Oil is supplied, and together with the above-mentioned supply of high-pressure oil during the ascent, more sufficient lubrication is performed, and the effect of preventing the occurrence of the abnormal wear phenomenon is further improved.

[Example code] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIGS. 2 to 4.

A tappet hole 21 whose lower end portion 21 has a large diameter is formed in the cylinder body 1 of an internal combustion engine, and inside the tappet hole 2o,
A tappet main body 30 having a large diameter lower end 32a is slidably fitted into the lower end 21 of the tappet hole 20.
A cylinder chamber 32 is defined by the lower end 32a of the tappet main body 30 and whose volume is controlled to increase or decrease.

The spherical lower end 41 of the bushing rod 4 is supported inside the tappet main body 30.

A concave spherical oil reservoir bottom 31 is formed in which oil flowing down from above is stored.

Further, a roller 5 is rotatably supported by a pin 6 in a four part 33 formed at the lower end 32 of the tappet body 30, and the roller 5 is in constant contact with a cam 7 driven by a crankshaft (not shown). The tappet body 30 and bushing rod 4 are configured to move up and down in response to this action.

Further, an oil passage 81 communicating with the bottom portion 31 and an oil passage 82 communicating with the cylinder chamber 22 are formed in the tappet body 30, respectively.

Further, the pin 6 is provided with an oil supply passage 91 that communicates with the oil passage 81 and the cylinder chamber 22 and opens on the outer peripheral surface of the pin 6.

In the roller tappet lubrication structure of the first embodiment configured as described above, when the tappet main body 30 is stationary, as shown in FIGS. 2 and 3, the oil accumulated on the bottom 31 of the tappet 30 is Due to natural flow from oil channel 81,
Further, when the tappet main body 3o is lowered, oil is supplied to the cylinder chamber 22 via the oil supply path 91 and the oil path 82 due to the suction action of the negative pressure generated in the cylinder chamber 22.

Next, as shown in FIG. 4, when the tappet body 30 rises as the roller 5 receives the pushing up action of the cam 7, the volume of the cylinder chamber 22 is reduced by the large-diameter lower end 32a of the tappet body 30. , the oil pressure in the cylinder chamber 22 increases.

Therefore, the high-pressure oil flows into the oil passage 82 and the oil supply passage 9 of the pin 6.
1, and is force-fed between the contact surfaces of the roller 5 and the pin 6.

In this way, high-pressure oil is generated in the cylinder chamber 22 every time the tappet body 30 rises due to the pushing-up action of the cam 7, and this high-pressure oil is supplied between the contact surfaces of the roller 5 and the pin 6. Sufficient lubrication between the surfaces is achieved, and the occurrence of abnormal wear phenomena is prevented.

Furthermore, when the tappet body 30 is lowered, the cylinder chamber 22 generates negative pressure as its volume increases, and oil is sucked from the bottom 31, so that oil is transferred to the contact surface between the roller 5 and the pin 6 through the oil supply path 91. Oil is also supplied during this period, and together with the above-mentioned supply of high-pressure oil during the ascent, more sufficient lubrication is performed, and the effect of preventing the occurrence of the abnormal wear phenomenon is further improved.

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 8.

In this embodiment, as particularly shown in FIG. 6, an oil passage 83 is formed in the tappet body 30 to communicate the bottom part 31 and the cylinder chamber 22 and whose opening on the bottom part 31 side is narrowed, and in the oil passage 83, A check valve 88 consisting of a ball 84, a coiled spring 86 that urges the ball 84 toward the throttle opening 85, and a stopper 87 for the spring 86 is provided, and an oil passage 82a formed in the tappet body 30 connects the cylinder chamber 22 and the pin. 6 oil supply path 9
1 and communicates with each other.

The other configurations are the same as those of the fjS1 embodiment, and will therefore be omitted.

In the roller tappet lubrication structure in the second embodiment configured as described above, when the tappet book 30 is lowered,
As shown in FIG. 7, the negative pressure generated by the increased volume of the cylinder chamber 22 causes the check valve 88 to open against the biasing force of the spring 86, allowing oil to directly flow into the cylinder chamber 22 from the bottom 31.

Then, the tappet body 3 is pushed up by the cam 7.
0 rises, as shown in FIG. 8, the pressure in the cylinder chamber 22 increases and the high-pressure oil flows through the oil passage 82a,
The oil is fed through the oil supply path 91 of the pin 6 between the contact surfaces of the roller 5 and the pin 6.

At this time, since the check valve 88 prevents oil from flowing into the bottom 31 side, the oil is forced to flow between the contact surfaces with a higher pressure.

Therefore, the lubrication between the contact surfaces of the roller 5 and the pin 6 is more sufficiently performed, and abnormal wear phenomena are prevented from occurring.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 to 11.

In this embodiment, a sheet member 50 that supports the lower end portion 41 of the bushing rod 4 and has an oil passage 51 communicating between the lower end surface and the side surface, and a rubber etc. for forming the pressure chamber 60a in the lower part thereof. The upper surface of the flange portion 35 is provided on the inner circumferential surface of the tappet body 30 so as to separate the elastic diaphragm-shaped pressure bottom plate 60 made of a bony member from the recess 33 for disposing the roller 5. It is attached to the section.

Further, the oil passage 51 of the seat member 50 is connected to the cylinder chamber 2.
2 by an oil passage 82c formed in the tappet body 30, and the cylinder chamber 22 is connected to the pin 6 by an oil passage 82d.
The tappet body 30 is connected to the bottom 31 of the tappet body 30 by an oil supply passage 91 and an oil passage 82e.

The other configurations are the same as those of the first embodiment, and will therefore be omitted.

In the roller tappet lubrication structure of the third embodiment configured as described above, when the tappet body 30 is at rest, the bottom portion 31 of the tappet body 30 as shown in FIG.
The oil accumulated on the upper surface of the sheet member 50 is removed from the oil passage 82e.
It is supplied to the cylinder chamber 22 through the cylinder chamber 22, and also supplied to the supply RIt path 91 of the pin 6 through the oil path 82d.

As shown in FIG. 11, when the tappet main body 30 rises due to the pushing up action of the cam 7, the oil that has become high pressure due to the pressure increase in the cylinder chamber 22 is transferred to the oil path 82d.
, is fed between the contact surfaces of the roller 5 and the pin 6 through the oil supply path 91 of the pin 6, and sufficient lubrication between the contact surfaces is performed.
Abnormal wear phenomena are prevented from occurring.

Furthermore, at the same time as the pressure feeding between the contact surfaces, the oil passage 82c,
The oil is also fed under pressure to the pressure chamber 60a above the pressure vent 60 through the oil passage 51 of the sheet member 50, and the pressure vent 60 expands downward in the figure.

Then, as shown in FIG. 10, when the tappet main body 3o descends, the pressure bottom vent 60 contracts, and the pressure chamber 6
The oil in 0a is transferred to the oil passage 51. oil passage 82c, cylinder 22,
The oil is fed under pressure between the contact surfaces of the rollers 5 and 6 through the oil passage 82d and the oil supply passage 91 of the pin 6.

Therefore, the pressure feeding of oil by this pressure bottom plate 60 and the pressure feeding of oil from the cylinder chamber 22 when the tappet main body 30 rises as described above combine to improve the oil supply between the contact surfaces of the rollers 5 and the pins 6. If this is done sufficiently, the effect of preventing the occurrence of the abnormal wear phenomenon will be further improved.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 12 to 14.

In this embodiment, a seat member 50a that supports the lower end 41 of the bushing rod 4 and has an oil passage 51a communicating between the upper and lower surfaces, and a pressure chamber 6 formed in the lower part of the seat member 50a.
A plate-shaped piston 14 having a coil-shaped leaf spring 15 is disposed inside 0b so as to be slidable in the vertical direction.

The pressure chamber 60b is connected to the cylinder chamber 22 by an oil passage 82 formed in the tappet body 30, and the cylinder chamber 22 is connected to the oil supply passage 91 of the pin 6 by an oil passage 82h, and the tappet is connected to the cylinder chamber 22 by an oil passage 82f. The bottom portion 31 of the main body 30 and the tappet main body 30 are connected so as to be communicable when the tappet main body 30 is at rest and when the tappet main body 30 is lowered.

The other configurations are the same as those of the first embodiment, and will therefore be omitted.

The roller tappet damper in the fourth embodiment configured as described above? l? In terms of structure, when the tappet body 30 is at rest, as shown in FIG. ,
The oil is also supplied from the cylinder chamber 22 to the oil supply path 91 of the pin 6 via the oil path 82h.

As shown in FIG. 14, when the tappet body 30 rises due to the push-up action of the cam 7, the high-pressure oil is released into the oil path 82f due to the pressure increase in the cylinder chamber 22.
, is fed between the contact surfaces of the roller 5 and the pin 6 through the oil supply path 91 of the pin 6, and sufficient lubrication between the contact surfaces is performed.
Abnormal wear phenomena are prevented from occurring.

Further, at the same time as the oil is fed between the contact surfaces, it is also fed under pressure to the pressure chamber 60b via the oil passage 82g, and the piston 14 is slid upward in the figure against the biasing force of the leaf spring 15.

Then, as shown in FIG. 13, when the tappet body 30 descends, the piston 14 descends, and its suppressing force causes the pressure chamber 6
The oil in 0b is pumped through the oil path 82g, the oil path 82h, and the oil supply path 91 of the pin 6 to the contact surface between the roller 5 and the pin 6.

Therefore, the pressure feeding of oil by the screws 1 to 14 and the pressure feeding of oil from the cylindrical chamber 22 when the tappet main body 30 rises as described above combine to supply oil to the contact surface between the roller 5 and the pin 6. is carried out more fully, and the effect of preventing the abnormal wear phenomenon from occurring is further improved.

[Effects of the Invention] As described above, the roller tappet lubrication structure according to the present invention has a tappet hole formed in a cylinder body and having a large diameter lower end, in which the lower end of the roller is rotatably supported by a pin. A tappet body having a large diameter is slidably fitted, and a cylinder chamber defined by the lower end of the tappet body is provided at the lower end of the tappet hole, and the cylinder chamber is connected to the bottom of the oil reservoir of the tappet body. and the pin oil supply passage are formed in the tappet body, so that
When the roller tappet rises due to the pushing up action of the cam,
II? in the cylinder chamber formed by the lower end of the tappet hole and the lower end of the tappet body. By pressurizing the accumulated oil and feeding it between the contact surfaces of the roller and the pin, sufficient lubrication between the contact surfaces is achieved, which has the effect of preventing abnormal wear phenomena due to insufficient oil supply. .

In addition, the roller tappet lubrication structure according to the present invention does not require major design changes to the cylinder body or lubricating oil piping system, so the structure is simple and has the advantage of being easy to implement both in terms of manufacturing and economics. There is.

The figures show a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the state of the tappet body at rest, FIG. 3 is a longitudinal sectional view showing the state of the tappet body when it is lowered, and FIG. 5 to 8 are longitudinal sectional views showing the state of the tappet body when it is raised, and FIG. 5 is a longitudinal sectional view showing the state when the tappet body is at rest, and FIG. The figure is an enlarged cross-sectional view of the main part of part ■ in Figure 5, No. 7 @ is a vertical cross-sectional view showing the state when the tappet body is lowered, Figure 8 is a vertical cross-sectional view showing the state when the tappet main body is raised, 9 to 11 show a third embodiment of the present invention, FIG. 9 is a vertical sectional view showing the state of the tappet body at rest, and FIG. 10 is a vertical sectional view showing the state of the tappet body when it is lowered. , FIG. 11 is a vertical sectional view showing the state of the tappet body when it is raised, and FIGS. 12 to 14 show a fourth embodiment of the present invention.

Fig. 12 is a longitudinal sectional view showing the state of the tappet main body when it is at rest, Fig. 13 is a longitudinal sectional view showing the state when the tappet main body is lowered, and Fig. 14 is a longitudinal sectional view showing the state when the tappet main body is rising. It is.

4...Butschrod, 5... Laura.

6...pin, 7...Cam.

20... Tappet hole.

21...Lower end of tappet hole.

22...Cylinder chamber.

30... Tappet body, 32a...lower end of tappet body, 88...Check valve.

50.50a... Sheet member, 60...pressure bottom plate.

60b...pressure chamber, 14...Plate-shaped piston, 15...temporary spring, 91...Refueling route.

Patent applicant: Isuzo Jidosha Co., Ltd. MI diagram
Figure 2 Figure 3 Figure 4 M5 Figure 6 L)
AFigure 9Figure 1oFigure 11Figure 12

Claims (1)

[Claims] A tappet body having a large diameter lower end, in which a roller is rotatably supported by a pin, is slidably fitted into a tappet hole formed in the cylinder body and having a larger diameter lower end. A cylinder chamber defined by a lower end of the tappet body is provided at a lower end of the hole, and an oil passage is formed in the tappet body to communicate the cylinder chamber with an oil reservoir bottom of the tappet body and the pin oil supply passage, respectively. Lubricating structure for roller tappets.