JP2001317430A - Tappet lubricating mechanism for fuel feed pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tappet lubricating mechanism that can offer forced lubrication to a tappet in a fuel feed pump without fixing a roller pin. SOLUTION: The tappet lubricating mechanism at least has an oil feed hole formed in a tappet body so as to communicate with a forced lubrication oil path, an annular groove formed in that periphery of a pin which is in one holding portion so as to communicate with the oil feed hole, and a lubricating groove formed in the periphery of the pin so as to communicate with the annular groove. Lubricating oil from the forced lubrication oil path is thus supplied via the oil feed hole and the annular groove to the lubricating groove formed in the periphery of the pin holding a roller, with the result that the lubricating oil can be forcibly supplied to the sliding contact surfaces of the roller and the pin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply pump for reciprocating a plunger by means of a camshaft rotated by an engine and for pumping the fuel by the plunger, and particularly to a high pressure generating pump for pumping the fuel to a common rail rail. The present invention relates to a tappet lubrication mechanism that converts rotation of a shaft into reciprocating motion of a plunger.

[0002]

2. Description of the Related Art In a fuel injection pump disclosed in Japanese Patent Application Laid-Open No. Hei 5-332222, a bushing is provided between a cam roller and a tappet pin, and a sliding surface between the bushing and the cam roller has a curved surface. The moving portion has a gap at the end portion along the axial direction of the tappet pin gradually larger than the gap at the center portion, and supplies the tappet body with lubricating oil between the bushing and the cam roller. A supply path is formed. As a result, in this reference, the cam roller can be inclined with respect to the bushing, and even if the cam shaft is bent, the cam roller is inclined, so that the contact surface with the cam does not come into contact with one another, and the contact surface between the cam roller and the bushing is lubricated. The supply of oil can prevent running out of lubricating oil, uneven wear and seizure.

A conventional tappet 100 shown in FIGS. 5 and 6 has a tappet body 101 including a cylindrical sliding portion 102 and a pin holding portion 103 formed at one end thereof, and a tappet body 101. Pin holding part 103
And a roller 105 rotatably held by the pin 104.
In addition, the tappet 100 is the same as the tappet body 101.
One end of the sliding portion 102 is open, and the other end is
A lubricating oil supply hole 106 is formed at one end of the pin 104. The lubricating oil supply hole 106 has an oil groove 107 formed in the outer peripheral surface of the pin 104 in the axial direction. This oil groove 10
7 needs to be shifted from the load point of the pin 104, the conventional example shown in FIG. 5 discloses that the pin 104 is fixed so as not to rotate by the pin 107, and FIG.
The conventional example shown in FIG. 1 discloses that the pin 104 is fixedly held by press-fitting the pin 104 into the pin holding portion 103, and both prevent rotation of the pin 104.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
In the fuel injection pump disclosed in JP-A-332222, the inlet side of the oil supply passage is opened to the upper part of the tappet main body, and lubricating oil leaked or dropped on the upper part of the tappet main body after lubricating the sliding surface of the plunger is supplied. Since the oil flows into the passage, there occurs a problem that the amount of lubricating oil reaching the oil supply passage is not constant.

The tappet forced lubrication mechanism disclosed in FIGS. 5 and 6 not only requires machining accuracy and assembly man-hours, but also causes the tappet to seize due to insufficient press-in force or breakage of the pin. Become.

Accordingly, an object of the present invention is to provide a tappet lubrication mechanism in a fuel supply pump that enables forced lubrication of a tappet without fixing a roller pin.

[0007]

According to the present invention, there is provided a tappet lubrication mechanism of the present invention comprising: a housing; a camshaft disposed through the housing and rotated by an engine; a roller abutting a cam surface of the camshaft; A pin that rotatably supports the roller and a cylindrical tappet main body in which both ends of the pin are held, and a tappet that reciprocates in the housing with the rotation of the camshaft, and is connected to the tappet; A plunger that reciprocates in a cylinder formed in the housing, a compression chamber whose volume changes with the reciprocation of the plunger, a suction valve that opens during a suction stroke in which the volume of the compression chamber increases, A forced-lubricating oil having at least a discharge valve that is opened in a discharge stroke in which the volume of the chamber is reduced, and forcibly lubricating each part by a pump. An oil supply hole formed in the tappet body and communicating with the forced lubricating oil path; and an oil supply hole formed in an outer peripheral surface of one of the holding portions of the pin, in the fuel supply pump having a passage in the housing. It is at least constituted by an annular groove communicating with the lubrication groove formed on the outer peripheral surface of the pin and communicating with the annular groove.

Therefore, according to the present invention, the lubricating oil is supplied from the forced lubricating oil path to the lubrication groove formed on the outer peripheral surface of the pin holding the roller via the oil supply hole and the annular groove. Lubricating oil can be forcibly supplied to the sliding contact surface between the pin and the pin, thereby solving the above-mentioned problem.

The lubrication groove is formed in an annular shape on a portion of the outer peripheral surface of the pin which is in sliding contact with the inner peripheral surface of the roller, and an axial through hole penetrates the pin in the axial direction. A first radially formed one end of the axial through hole;
And a second radial through-hole formed in the other end of the axial through-hole in the radial direction. As a result, the lubricating oil pumped from the forced lubricating oil passage passes through the first radial through-hole, the axial through-hole, and the second radial through-hole, and contacts the outer peripheral surface of the pin with the roller. The lubricating oil is always supplied to the sliding contact surface between the pin and the roller even if the pin rotates together with the roller, because the oil is supplied to the annular groove formed in the sliding contact surface in an annular shape.

Further, the lubrication groove may be formed in a spiral shape on the outer peripheral surface of the pin, and one end thereof may communicate with the annular groove. Furthermore, the other end of the lubrication groove may extend to an end of a sliding contact portion of the roller, and the other end of the lubrication groove may be formed to an end of the pin. It may be something that is. Since the annular groove is formed in a spiral shape, lubricating oil can always be supplied to the sliding contact surface with the roller.

Further, it is preferable that the fuel supply pump is a common rail rail high pressure pump for pumping fuel to a common rail.

[0012]

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

A fuel supply pump 1 as a high-pressure supply pump for a common rail has a camshaft 4 disposed through a lower space 3 defined in a housing 2 and rotated by an engine (not shown). A tappet 6 is provided in a sliding space 8 extending upward from the space 3 to abut on the cam surface 5 of the camshaft 4 and convert the rotation of the camshaft 4 into a reciprocating motion.

A plunger barrel 7 is disposed above the tappet 6 so as to extend into the sliding space 8. A cylindrical cylinder portion 9 defined in the plunger barrel 7 includes the tappet 6. A plunger 10 fixed to the upper end of 6 is slidably disposed. At the upper end of the tappet 6, a spring 11 for pressing the tappet 6 against the cam surface 5 is provided. As a result, the tappet 6 reciprocates in accordance with the undulation of the cam surface 5 which changes due to the rotation of the camshaft 4. This is for changing the volume of the chamber 12.

A valve block 13 is fitted into the plunger barrel 7 to close one end of the compression chamber 12, and the valve block 13 comprises an IO (inlet / outlet) valve 14 and a delivery valve holder 15. Is done. The IO valve 14 is
An inlet valve that opens in a stroke in which the plunger 10 descends and expands the compression chamber 12 to supply fuel delivered from a feed pump (not shown) to the compression chamber 12, and closes in a stroke in which the plunger 10 rises and the compression chamber 12 contracts. Part 16
And an outlet valve section 17 for discharging the fuel in the compression chamber 12 by closing the plunger 10 in a stroke in which the compression chamber 12 expands and lowering in a stroke in which the plunger 10 rises and the compression chamber 12 contracts. Is done. Further, the delivery valve holder 15 is connected to a common rail (not shown) via a pipe.

The housing 2 is provided with a forced lubricating oil passage 19 which is connected to the engine and is driven to communicate with a pump 18 for forcibly sending lubricating oil to each part. 19 is a part of the sliding space 8.
The tappet 6 communicates with a lubricating oil groove 21 formed on the sliding surface 20 of the tappet 6.

As shown in FIGS. 2 to 4, the tappet 6 has a cylindrical sliding portion 62 slidably inserted into the cylindrical sliding surface 20 and a shaft of the sliding portion 62. The tappet body 61 includes a roller holding portion 63 extending to one end in the direction, a pin 64 whose both ends are held by the roller holding portion 63 of the tappet body 41, and a pin 6.
4 and a roller 65 rotatably held. A spring 1 is provided inside the sliding portion 62.
A spring holding portion 67 for holding one end of the plunger 1 and a plunger holding portion 68 for contacting one end of the plunger 10 are formed.

The tappet 6 is provided with the sliding portion 6
An oil supply hole 66 is formed at one end of the outer peripheral side surface and opens at one roller holding portion 63 holding the pin 64 at the other end. Open to As a result, lubricating oil is forcibly supplied to the oil supply hole 66 from the forced lubricating oil passage 19. An annular groove 69 is formed on the outer peripheral surface of the pin 64 facing the other end of the oil supply hole 6.

In the tappet 6 according to the first embodiment shown in FIG. 2, the pin 64 is formed with an axial through hole 70 penetrating in the axial direction. First and second radial through holes 71a and 71b are formed. The first radial through-hole 71 a communicates with the annular groove 69. A lubrication groove 80 is formed in a portion (sliding surface) 73 on the outer peripheral surface of the pin 64 and in sliding contact with the inner peripheral surface 72 of the roller 65, and the second radial through hole is formed. It communicates with 71b. The axial through hole 70 is formed by drilling one end of the pin 64 with a drill or the like, and then closing the opening with a seal member 74.

As a result, the oil supply hole 66, the annular groove 69, the first radial through hole 71a, the axial through hole 70,
And the lubrication groove 80 via the second radial through hole 71b,
Since the lubricating oil is forcibly supplied from the forced lubricating oil passage 19, lubrication between the inner peripheral surface 72 of the roller 65 and the sliding surface 73 of the pin 64 can be reliably performed. Further, even if the pin 64 rotates together with the roller 65, no problem occurs.

Hereinafter, other embodiments will be described. The same portions or portions having similar effects are denoted by the same reference numerals, and description thereof is omitted.

A tappet 6A according to a second embodiment shown in FIG. 3 is characterized in that the lubrication groove 81 is formed in a spiral shape on the outer peripheral surface of the pin 64. One end of the lubrication groove 81 communicates with the annular groove 69, and is inclined from the one end toward the rear in the rotation direction of the roller 65 so as to extend to the end 83 of the sliding contact surface 73. It is formed. In this embodiment, the lubrication grooves 81
Is formed only up to the end portion 83 of the sliding contact surface 73, so that the lubricating oil holding property on the sliding contact surface 73 can be improved. The lubrication between the pin 64 and the roller 65 can be improved by rotating the pin 64 with the rotation of the roller 65.

In the tappet 6B according to the third embodiment shown in FIG. 4, the other end 83A of the lubrication groove 81A is connected to the pin 64
Is formed so as to extend to the other end. In this embodiment, the sliding contact surface 7 is different from that of the second embodiment.
3, the pin 64 rotates with the rotation of the roller 65, so that the lubrication groove 81A
Therefore, the lubricating oil can be sucked, and the lubricity between the pin 64 and the roller holding portion 63 can be further improved.

[0024]

As described above, according to the present invention, lubricating oil can be forcibly supplied to the sliding surface between the pin and the roller, and the lubricating groove can be spread over the entire sliding surface. Since it is formed in an annular or helical shape, the lubrication on the sliding contact surface can be improved and the sticking of the tappet can be prevented.

Further, since it is not necessary to fix the pins, equipment for press-fitting the pins, man-hours for assuring the accuracy, and man-hours for assembling can be reduced, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a fuel supply pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of the tappet according to the first embodiment.

FIG. 3 is a sectional view of a tappet according to a second embodiment.

FIG. 4 is a sectional view of a tappet according to a third embodiment.

FIG. 5 is a sectional view showing a conventional tappet.

FIG. 6 is a sectional view showing another conventional tappet.

[Explanation of symbols]

 Reference Signs List 1 fuel supply pump 2 housing 4 cam 6, 6A, 6B tappet 9 cylinder 10 plunger 12 compression chamber 14 IO valve 15 inlet valve section 16 outlet valve section 19 forced lubricating oil path 61 tappet body 62 sliding section 63 roller holding section 64 pin 65 Roller 66 Oil supply hole 69 Annular groove 70 Axial through hole 71a First radial through hole 71b Second radial through hole 72 Inner peripheral surface (of roller) 73 Sliding contact surface 80, 81, 81A Lubrication groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Osamu Takahashi 3-13-26, Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Inside of Zexel Higashimatsuyama Plant (72) Inventor Tetsuya Yagawa 3--13, Yayumicho, Higashimatsuyama-shi, Saitama No. 26 F-term in Zexel Higashi-Matsuyama Plant (reference) 3G066 AA07 AB02 AC09 AD02 BA29 CA01S CD07 CE05

Claims (6)

[Claims] 1. A housing, a camshaft penetrating through the housing and rotated by an engine, a roller contacting a cam surface of the camshaft, a pin rotatably supporting the roller, and both ends of the pin. And a plunger that is reciprocated in the housing with the rotation of the camshaft, and is connected to the tappet and reciprocates in a cylinder formed in the housing. A compression chamber whose volume changes with the reciprocation of the plunger, a suction valve that opens in a suction stroke in which the volume of the compression chamber increases, and a discharge valve that opens in a discharge stroke in which the volume of the compression chamber decreases. A fuel supply pump having at least a forced lubricating oil path in the housing for forcibly lubricating each component by a pump, An oil supply hole formed in the tappet main body and communicating with the forced lubricating oil path; an annular groove formed on one outer peripheral surface of the holding portion of the pin and communicating with the oil supply hole; A tappet lubrication mechanism for a fuel supply pump, characterized by being formed at least by a lubrication groove formed and communicating with the annular groove. The lubrication groove is formed in an annular shape in a portion that is an outer peripheral surface of the pin and slides on an inner peripheral surface of the roller, and an axial through hole that penetrates the pin in an axial direction. The annular groove is formed by a first radial through hole formed radially at one end of the axial through hole and a second radial through hole radially formed at the other end of the axial through hole. The tappet lubrication mechanism for a fuel supply pump according to claim 1, wherein the tappet lubrication mechanism is connected to the lubrication pump. 3. The tappet for a fuel supply pump according to claim 1, wherein the lubrication groove is formed in a spiral shape on an outer peripheral surface of the pin, and one end of the lubrication groove communicates with the annular groove. Lubrication mechanism. 4. The roller according to claim 3, wherein the other end of the lubrication groove extends to an end of a sliding portion of the roller.
A tappet lubrication mechanism for the fuel supply pump as described. 5. The tappet lubrication mechanism according to claim 3, wherein the other end of the lubrication groove is formed up to an end of the pin. 6. The tappet lubrication mechanism for a fuel supply pump according to claim 1, wherein the fuel supply pump is a common rail high pressure generating pump for pumping fuel to a common rail. .