JPH0558853U - Timer device for distributed fuel injection pump - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a timer device for a distributed fuel injection pump capable of preventing sticking of a timer piston. A timer device for a distributed fuel injection pump, in which an end plate is bolted to an end of a cylinder, on which a timer piston slides, on the high pressure chamber side via an annular seal member. At the end of the cylinder on the high pressure chamber side, a circumferential groove is provided which is located outside the seal member and inside the bolt and extends in the circumferential direction.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a timer device for a distributed fuel injection pump, and more particularly to a timer device that prevents deformation of a cylinder due to heat.

[0002]

[Prior Art]

 Generally, there is known a timer device in which an end plate is bolted to an end of a cylinder on which a timer piston slides on the high pressure chamber side through an annular seal member.

In this type of conventional timer device, when the fuel pressure in the suction space rises as the pump speed increases, the fuel is received by the end of the cylinder on the high pressure chamber side and the timer piston slides. It is moved to advance the rotation angle.

[0004]

[Problems to be solved by the device]

 However, in the conventional configuration, the clearance between the timer piston and the cylinder is designed to be as small as possible in order to reduce the fuel leak amount and stabilize the timer characteristics. Has the problem of sticking on the timer piston.

Therefore, an object of the present invention is to provide a timer device for a distribution type fuel injection pump that can solve the problems of the above-mentioned conventional techniques and prevent stick from occurring.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is a timer device for a distributed fuel injection pump, in which an end plate is bolted to an end of a cylinder on which a timer piston slides on the high pressure chamber side through an annular seal member. In the above-mentioned cylinder, a peripheral groove extending in the circumferential direction is provided at the end of the cylinder on the high pressure chamber side, the peripheral groove being located outside the seal member and inside the bolt.

[0007]

[Action]

 According to the present invention, since the peripheral groove is provided at the end of the cylinder located outside the seal member and inside the bolt, even if the high pressure side of the cylinder is deformed by heat, the deformation is bounded by the peripheral groove. Since it appears on the outer peripheral side of the end portion and does not extend to the inside of the peripheral groove, sticking of the timer piston is prevented.

[0008]

【Example】

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

In FIG. 1, the distributed fuel injection pump has a housing 2 that forms a suction space 1, and a drive shaft 3 is inserted into the housing 2. The drive shaft 3 is rotated by an engine as a drive source, a feed pump 4 is mounted on the drive shaft 3, and fuel is supplied to the suction space 1 by driving the feed pump 4. The fuel pressure in the suction space 1 is controlled by a regulating valve (not shown) so as to correspond to the engine speed.

A cylinder 5 is fixed to one end of the housing 2, and a plunger 6 is slidably inserted into the cylinder 5. The high pressure chamber 7 is surrounded by the cylinder 5 and the plunger 6. Is configured.

The plunger 6 is fitted to the drive shaft 3 via a cam disk 8. A cam is formed on the peripheral edge of the other surface of the cam disk 8, and a roller 9 abuts on the cam. The roller 9 is rotatably supported by a roller holder 10. Therefore, the plunger 6 reciprocates along the cam profile and rotates together with the drive shaft 3 and the cam disk 8. The roller holder 10 is connected to a timer 11. The timer 11 is operated by the fuel pressure in the suction space 1 to rotate and advance the roller holder 10 according to the engine speed. ..

In the aforementioned plunger 6, suction groups 12 are formed at the front end facing the high pressure chamber 7 in the number corresponding to the number of engine cylinders. Further, a suction port 13 is formed in the cylinder 5 so as to communicate with the suction group 12 at a predetermined angle. The other end of the suction port 13 communicates with the suction space 1 via a suction passage 14 formed in the housing 2. Further, a vertical hole 15 is formed in the axial direction of the plunger 6 so that one end thereof opens into the high pressure chamber 7. A distribution port 16 formed in the plunger 6 communicates with the vertical hole 15, and the distribution port 16 communicates with a distribution passage 17 formed in the housing 2 and the cylinder 5 at a predetermined angle.

The distribution passage 17 is connected to an injection pipe 19 via a delivery valve 18, and the injection pipe 19 is connected to an injection valve 20. A spill port 21 communicates with a portion of the other end of the vertical hole 15 which faces the suction space 1. A control sleeve 22 is fitted around the spill port 21, and the control sleeve 22 is provided from the governor. The displacement is adjusted according to the output to adjust the injection amount.

Such a distribution type fuel injection pump itself is known. Therefore, according to the present embodiment, the timer 11 is characterized in that the timer 11 is configured so that the timer characteristics do not become unstable even if thermal deformation occurs.

That is, as shown in FIG. 2, the timer 11 has an aluminum cylinder 31, in which a timer piston 33 is slidably inserted, and the timer piston 33 is inserted through a timer pin 34. Is connected to the roller holder 10.

The low-pressure side of the timer piston 33 is biased by the timer spring 35, a high-pressure chamber 37 is formed on the high-pressure side, and the fuel in the suction space 1 is introduced into the high-pressure chamber 37 through a passage 39. ing. Further, as shown in FIG. 4, an O-ring groove 41 is formed at the end 31a of the aluminum cylinder 31 on the high-pressure chamber 37 side, and an O-ring 43 is fitted in the O-ring groove 41. An end plate 45 made of iron is assigned to the end 31a of the cylinder 31 and the end plate 45 is fixed to the end 31a of the cylinder 31 via a plurality of bolts 47.

Further, a peripheral groove 51, which is located outside the O-ring groove 41 and inside the bolt 47 and extends in the circumferential direction of the end portion 31 a, is formed in the end portion 31 a of the cylinder 31.

By the way, in the timer device having such a configuration, when the pressure of the fuel in the suction space 1 rises, the pressure in the high pressure chamber 37 rises, and as shown in FIG. 3, the spring force of the timer spring 35 is increased. Against this, the timer piston 33 slides in the direction shown, and the roller holder 10 rotates in the direction of the arrow via the timer pin 34, so that the rotation angle is advanced.

When the fuel temperature rises due to the operation of the engine or the like, the cylinder 31 is made of aluminum, while the end plate 45 is made of iron, so the thermal expansion amount of the cylinder 31 is larger than that of the end plate 45. Is increased, and the high pressure side of the cylinder 31 is deformed as shown in FIG.

According to this embodiment, however, since the peripheral groove 51 is provided at the end portion 31a of the cylinder 31, even if the high pressure side of the cylinder 31 is deformed by heat, the deformation causes the peripheral groove 51 to be deformed. It appears on the outer peripheral side of the end portion 31a as a boundary and does not extend to the inside of the peripheral groove 51. Therefore, at this time, the timer piston 33 does not stick.

Referring to FIG. 6, in comparison with a cylinder 31 having no peripheral groove 51 at the end 31 a (conventional timer device), in this conventional type timer device, deformation of the cylinder 31 on the high pressure side is prevented. However, since it directly reaches the inner peripheral portion of the cylinder 31, the stick 53 is generated in the timer piston 33. When the stick 53 is generated, the operation of the timer 11 becomes unstable, and, for example, an advance angle delay occurs, which causes inconveniences such as an increase in white smoke, HC, and CO.

According to the present embodiment, in such a case, the circumferential groove 51 provided in the end portion 31a of the cylinder 31 functions extremely effectively, so that even if the high pressure side of the cylinder 31 is deformed by heat, Compared to the conventional one, the stick of the timer piston 33 is significantly suppressed, and stable timer characteristics are maintained.

[0023]

[Effect of the device]

 As is apparent from the above description, according to the present invention, the circumferential groove, which is located outside the seal member and inside the bolt and extends in the circumferential direction, is provided at the end of the cylinder on the high-pressure chamber side. Even if the high-pressure side of the cylinder is deformed by heat, the deformation appears on the outer peripheral side of the end portion with the peripheral groove as a boundary and does not reach the inside of the peripheral groove, so that sticking of the timer piston can be prevented.

Further, since the influence of cylinder deformation due to heat is eliminated, it is possible to further reduce the clearance between the timer piston and the cylinder from the current state. This reduces the amount of fuel leakage from the timer high-pressure chamber that passes between the timer piston and the cylinder when the fuel viscosity decreases due to the increase in fuel temperature, and therefore the stability of the timer characteristics against changes in fuel temperature is achieved. improves.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a distribution type fuel injection pump.

FIG. 2 is also a diagram showing a timer device.

FIG. 3 is a diagram showing an operating state of the timer device of FIG.

FIG. 4 is a sectional view showing an essential part of the present invention.

FIG. 5 is a cross-sectional view showing a deformed cylinder of the timer device of the present invention.

FIG. 6 is a cross-sectional view showing a deformed cylinder of a conventional timer device.

[Explanation of symbols]

 1 Suction Space 6 Plunger 8 Cam Disc 11 Timer 31 Cylinder 31a End 33 Timer Piston 34 Timer Pin 37 High Pressure Chamber 41 O Ring Groove 45 End Plate 47 Bolt 51 Circumferential Groove 53 Stick

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Ryoichi Kawashima 3-13-26, Yasumi-cho, Higashimatsuyama, Saitama Prefecture Zexel Higashimatsuyama Factory

Claims (1)

[Scope of utility model registration request] 1. A timer device for a distribution type fuel injection pump, wherein an end plate is bolted to an end of a cylinder on which a timer piston slides on the high pressure chamber side through an annular seal member. A timer device for a distributed fuel injection pump, characterized in that a peripheral groove, which is located outside the seal member and inside the bolt and extends in the circumferential direction, is provided at an end portion on the high pressure chamber side.