JPH0413412Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air bleed device for a fuel path from a fuel tank to an engine.

[Prior art and problems to be solved by the invention] Generally, members such as a pump, a filter, and an injection pump if the engine is a diesel engine are provided in the fuel path from the fuel tank to the engine. By the way, in such a device, air may enter the path when the filter is inspected or the fuel runs out, and in this case, air must be removed. Conventionally, the filter and injection pump had oil passages dedicated to air bleed, and air was bled from there. In anticipation of this, the discharge amount needs to be greater than the amount supplied to the engine, which inevitably results in a larger size, and there is also a lot of dirt and dust accumulation in the filter and piping, which puts a heavy burden on the fuel pump. It used to be a cause of failures. Therefore, as shown in Japanese Utility Model Application Publication No. 53-103019, there is a filter in which an air bleeder is provided in the filter so that the air is bleed when the operation button is pressed. This method is problematic because it requires the user to keep pressing the operation button throughout the air bleeding process, which makes the operation cumbersome and complicated, resulting in poor workability.

[Means for solving the problem] In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a fuel path air bleed device that can eliminate these drawbacks. An air bleed pipe is formed by branching in the fuel path from the tank to the engine, and an air bleed valve is installed in the air bleed pipe to open and close the pipe path by displacing the valve body. The air bleed valve is always biased toward the closing side, and does not apply braking to the valve body's displacement toward the open side, but does apply braking to the displacement toward the closing side, making it slow. It is characterized by being provided with a displacement braking mechanism that forces displacement of the valve body.

With this configuration, the present invention makes it possible to bleed air from the pipes quickly, reliably, and efficiently.

[Example] Next, an example of the present invention will be described based on the drawings. In the drawing, 1 is a combine harvester,
A fuel tank 3 is installed below a seat 2 of the combine 1. A series of fuel paths from the fuel tank 3, through the fuel pump 4, filter 5, and injection pump 6 to the injection nozzle 7 provided in each cylinder of the engine, and from the injection nozzle 7 back to the extra fuel tank 3 are connected to the piping 8. The structure and other features are all the same as before.

10 is an air bleed valve, and the air bleed valve 10
is the inlet port 1 connected to the air vent pipes 5a and 6a from the filter 5 and the injection pump 6, respectively.
This is a three-port type in which a port 0a and an outlet port 10b connected to a return pipe 3a leading to the fuel tank 3 are formed in the case body 11. This air bleed valve 10 has a valve body 12 movably provided in a case 11.
The oil chamber 1 is formed by cutting out the outer circumference of the oil chamber 1.
3 is constantly biased toward the closed position to increase the capacity of the second oil chamber 13a formed between the front end surface of the valve body and the inner bottom surface of the case 11. ing. In this state, the oil groove 15 is biased with respect to both ports 10a and 10b, and the inlet port 10a and outlet port 10b are in a non-conducting state, and the filter 5 and injection pump 6 side The air bleed oil passage from the fuel tank 3 to the fuel tank 3 is closed. and valve body 12
When the operating part 12a of is pushed against the ammunition 14,
The oil groove 15 is located at a position corresponding to the ports 10a, 10b, so that the ports 10a, 1 on both sides
0b communicates, the air bleed oil passage opens, and the filter 5
Together with the air fuel on the injection pump 6 side, the air flows back into the fuel tank 3 through the air bleed valve 10 which is opened.

On the other hand, a communication hole 1 is provided in the valve body 12 so that the inlet port 10a, the oil groove 15, and the first oil chamber 13 communicate with each other when the air bleed oil passage is closed.
6 is formed between the first oil chamber 13 and the second oil chamber 13a, which is opened when the valve body 12 is displaced to the open side and does not brake the displacement of the valve body 12. , a check oil passage 17 with a check valve 17a that closes when the valve body 12 moves to the closing side and brakes the movement of the valve body 12, and a small diameter hole that serves as an oil passage when the valve body 12 moves to the closing side. A throttle valve passage 18 is formed and constitutes the displacement braking mechanism of the present invention.

In the embodiment of the present invention constructed as described above, the fuel in the fuel tank 3 is supplied to the engine via the fuel pump 4, the filter 5, and the injection pump 6. When you want to bleed air, if you push the valve body 12 against the bullet 14 and operate the fuel pump 4 in the open position, the fuel from the filter 5 and the injection pump 6 will flow out of the air. The air flows back to the fuel tank 3 from the vent pipes 5a and 6a through the air vent valve 10 and the return pipe 3a, thereby achieving air venting. When the air bleed work is completed, when the valve body 12 is released, the biasing force of the bullet 14 automatically switches the air bleed valve 10 to the closed side, cutting off the air bleed path. Reflux stops.

As described above, in the present invention, the necessary air bleeding operation can be easily and reliably performed by operating the valve body. Since this air vent is normally closed when it is not needed, the fuel does not constantly circulate, and therefore there is no need to increase the discharge amount of the combustion pump 4 more than necessary. Can be made lightweight and compact.

Furthermore, in this case, when the valve body 12 is pushed in to bleed air, the oil in the second oil chamber 13a quickly flows mainly through the thick check oil passage 17 to the first oil chamber 13 side. When the valve body 12 is released from the open state, the valve body 12 is released.
The valve body 12 receives the biasing force of the ammunition 14 and immediately tries to return to the closed side. However, the first oil chamber 13
Since the thick check oil passage 17 is closed, the oil inside cannot flow through the narrow check oil passage 1.
8 and gradually flows to the second oil chamber 13a side. Therefore, the valve body 12 returns at a slow speed while being braked, contrary to when it is operated to the open side. As a result, valve body 1
2, even if you immediately release the push-in operation after pushing it to the open side, it will remain in the open state for a while, and the air bleeding work will continue without any intervention during this time. As a result, there is no need to forget to put it back, and work efficiency is significantly improved, resulting in improved efficiency.

Furthermore, since the first oil chamber 13 is open and communicates with the piping side, the first oil chamber 13 is always maintained at the same oil pressure as the piping regardless of the movement of the valve body 12. The Rukoto. Therefore, even if the oil in the second oil chamber 13a flows toward the first oil chamber 13 during the pushing operation of the valve body 12, the pressure in the first oil chamber 13 will not become high and the pressure will be maintained at a constant pressure. Therefore, the valve body 1
2, the return will not be accelerated due to the high pressure in the first oil chamber 13, and the return will always be stable and slow.

[Operations and Effects] In short, the present invention is constructed as described above, so an air bleed valve is provided in the air bleed pipe branched into the fuel path, and the air bleed valve is opened only when necessary. By bleeding air, it is possible to eliminate unnecessary fuel supply from the fuel pump and contribute to making the fuel pump lighter and more compact. The valve body is quickly displaced toward the open side by the displacement braking mechanism, but the valve body is displaced toward the closed side at a slow speed due to braking. As a result, even if you take your hand off the valve body after operating the valve body to the open side, the valve body can remain open for a while. Air bleeding work can be continued for a while without continuing to operate to the open side, resulting in a significant improvement in workability.

[Brief explanation of the drawing]

The drawings show an embodiment of the air bleed device for the fuel path according to the present invention, in which FIG. 1 is an overall perspective view of the combine harvester, FIG. 2 is a piping diagram of the fuel path, and FIG. Cross-sectional view of the vent valve in the closed state, No. 4
The figure is a sectional view of the same as the above in an open state, and FIG. 5 is a horizontal sectional view of the same as the above. In the figure, 4 is a fuel pump, 5 is a filter, 6 is an injection pump, 10 is an air bleed valve, 12 is a valve body,
13 and 13a are oil chambers, 17 is a check valve, and 18 is a throttle oil passage.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An air bleed pipe is formed by branching in the fuel path from the fuel tank to the engine, and the air bleed pipe is operated by displacement of a valve body to open and close the piping path. In this air bleed valve, the valve body is always biased toward the closing side, and the displacement of the valve body toward the open side is not braked, but the displacement toward the closing side is 1. A fuel path air bleed device characterized by being provided with a displacement braking mechanism that applies a brake to displacement and forces a valve body to slowly displace. 2. The fuel path air bleed device according to claim 1, wherein the displacement braking mechanism is comprised of a check valve oil passage and a throttle valve oil passage provided in the valve body. 3. The fuel path air bleed device according to claim 1, wherein the oil chamber provided in the valve body is communicated with piping.