JP2562173Y2 - Oil relief device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil relief device for an oil pump mounted on an automobile engine or the like .

[0002]

2. Description of the Related Art In this type of oil relief device, a drain hole is provided in a valve accommodating chamber provided in communication with a discharge side passage of a pump circuit, and a valve body for opening / closing the drain hole has a valve closing direction. (In the direction to close the drain hole) with the spring biased, when the hydraulic pressure in the discharge side passage exceeds a set value, this hydraulic pressure pushes back the valve body against the spring force of the spring, and the oil Part of the fluid is released from the drain hole, and thereby the fluid pressure in the discharge-side passage is maintained at a set value or less.

However, in the case of an oil relief device having a fixed valve opening pressure (hereinafter referred to as "relief pressure"), a desired oil discharge pressure corresponding to the operating condition of the engine cannot be obtained. In the past , it was possible to increase or decrease the relief pressure according to the operating conditions of the engine.
More developed.

In this conventional oil relief device, an operation unit including a cam mechanism for mechanically switching a set length of a spring for biasing a valve element is provided in a valve accommodating chamber.
The operating portion is moved in accordance with the operating state of the engine, for example, the number of rotations or the load, to change the set length of the spring, thereby increasing or decreasing the relief pressure.

Incidentally, this similar technique is disclosed in Japanese Utility Model Laid-Open No. 63-735.
No. 10 publication.

[0006]

However, the conventional oil relief device described above has a structure in which the relief pressure is increased or decreased by mechanically operating the set length of a spring for biasing the valve element. Therefore, an extremely large operation force is required to adjust the relief pressure, and this has necessitated a complicated and large operation unit.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oil relief device capable of simplifying and reducing the size of an operation section by making it possible to increase and decrease the relief pressure with an extremely small operation force.

[0008]

According to the present invention, as a means for solving the above-mentioned problems, a valve accommodating chamber which communicates with a discharge-side passage of a pump circuit, a drain hole provided in the valve accommodating chamber are provided. It has a drain hole and always communicating through holes in the peripheral wall and slidably is furnished to the valve accommodating chamber, itself
A movable cylinder that defines the valve housing chamber a working pressure chamber for advance and retreat operation of slidably decorated in該可Do cylinder, wherein Ru is spring biased to close the through-hole direction one-
A valve body that receives the pressure of the discharge-side passage in a direction in which the through-hole is opened , and a pressure adjusting unit that is connected to the operating pressure chamber and adjusts the pressure of the operating pressure chamber. .

[0009]

By adjusting the pressure in the working pressure chamber by the pressure adjusting means, the movable cylinder is moved forward and backward to adjust the position of the through hole.
The relief pressure is increased or decreased by changing the stroke of the spring until the valve element opens the through hole .

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings.
I will tell.

In FIG . 1 , reference numeral 2 denotes a valve storage chamber 2 which communicates with a discharge side passage 1 of a pump circuit via a passage 3. The valve storage chamber 2 has a drain hole for allowing oil introduced therein to escape. 4, and a substantially cylindrical movable cylinder 19 is slidably mounted therein. The movable cylinder 19 has a small diameter portion 20 having a small outer diameter formed on one end side,
In a state of being urged to the other end by a spring 21, the small diameter portion 20 is slidably fitted into the guide hole 10 formed at the end of the passage 3 side of the valve chamber 2. And
Inner peripheral surface of valve storage chamber 2 and end of general portion of movable cylinder 19
The space surrounded by the surface and the outer peripheral surface of the small diameter portion 20 is a working pressure chamber 22 for moving the movable cylinder 19 forward and backward . Further, a through hole 23 penetrating through the inner and outer surfaces of the general portion of the movable cylinder 19 is formed in the peripheral wall, and the inside of the movable cylinder 19 communicates with the drain hole 4 through the through hole 23. Incidentally, the diameter set sufficiently large drain hole 4, through-holes 23 regardless of the forward and backward position of the movable cylinder 19 is adapted to communicate with constantly drain hole 4.

Reference numeral 24 denotes a valve body slidably mounted in the movable cylinder 19, and the valve body 24 has one end (lower in the figure).
The spring 25 supported on the end wall of the valve housing chamber 2 at the end)
Urged in the direction of the passage 3. Also, the valve element 24
A communication passage 26 communicating from the end on the side of the passage 3 to the outer peripheral surface is formed in the inside of the valve body 24. Further, an annular groove 27 is formed in a portion of the outer peripheral surface of the valve body 24 where the end of the communication passage 26 opens.
Are formed. This annular groove 27 is offset from the through hole 23 of the movable cylinder 19 while the hydraulic pressure of the discharge side passage 1 is small and the valve body 24 is located on the side of the passage 3, The pressure rises and the valve body 24 springs
When a predetermined amount is displaced against the spring force of the
A part of the oil in the discharge side passage 1 through the drain hole 4
Let go.

Reference numeral 28 denotes a pressure introduction passage for introducing the hydraulic pressure of the discharge side passage 1 into the working pressure chamber 22. In the middle of the pressure introduction passage 28, an opening / closing valve 12 operated by the solenoid 11 is interposed. Is equipped. The solenoid 11
An opening / closing operation is performed in response to an engine speed signal A and a load signal B of the engine . In this embodiment, the pressure adjusting means for adjusting the pressure in the working pressure chamber 22 is constituted by the pressure introducing passage 28 and the on-off valve 12.

In the case of this oil relief device, while the engine speed and load are small, the on-off valve 12 closes the pressure introduction passage 28 and no hydraulic pressure is introduced into the working pressure chamber 22. As shown in FIG. 1 , the valve element 24 is pushed by the spring 21 and is positioned closest to the passage 3. When the hydraulic pressure of the discharge side passage 1 rises in this state, the hydraulic pressure comes to push back the valve element 24 against the spring force of the spring 25, and when the hydraulic pressure of the discharge side passage 1 reaches the set value. The annular groove 27 of the valve body 24 communicates with the through hole 23 of the movable cylinder 19, and a part of the oil in the discharge side passage 1 escapes to the drain hole 4 through the through hole 23 to reduce the hydraulic pressure in the discharge side passage 1 to the low pressure side. Keep below the set value of.

When the number of revolutions and load of the engine becomes larger than a certain value, the on-off valve 12 is connected to the pressure introducing passage 28.
And the hydraulic pressure in the discharge side passage 1 is introduced into the working pressure chamber 22, whereby the movable cylinder 19 is displaced away from the passage 3 against the spring force of the spring 21. When the hydraulic pressure in the discharge side passage 1 increases in this state, the valve body 24 is pushed back against the spring force of the spring 25 , and the annular groove 27 is
A part of the oil in the discharge side passage 1 is made to escape from the drain hole 4 by communicating with the through hole 28, but at this time, the through hole 23 of the movable cylinder 19 is displaced by a predetermined amount in a direction away from the passage 3. For this reason, the stroke until the spring 21 is compressed and the annular groove 27 communicates with the through hole 23 becomes larger than in the case described above. For this reason, the hydraulic pressure required to secure this stroke, that is, the relief pressure, also increases.

In the embodiment described here, the hydraulic pressure of the discharge side passage 1 is used as the pressure supplied to the working pressure chamber 22, but another pressure supply means is connected to the pressure introducing passage 28 for use. It is also possible.

[0017]

[Effects of the Invention] As described above, the present invention uses a pump.
A valve storage chamber communicating with the discharge side passage of the circuit;
The drain hole provided is always in communication with the drain hole.
Having a through hole in the peripheral wall and slidably into the valve chamber
It is equipped with a working pressure chamber for operating itself.
A movable cylinder defined in the accommodation room and the movable cylinder
It is slidably mounted and split in the direction to close the through hole.
While the discharge side passage is opened in the direction to open the through hole.
A valve body for receiving the pressure of the passage and connected to the working pressure chamber
Pressure adjusting means for adjusting the pressure of the working pressure chamber.
With this configuration, the relief pressure can be increased or decreased by changing the pressure introduced into the working pressure chamber by the pressure adjusting means and operating the position of the through hole of the movable cylinder. Therefore, the relief pressure can be adjusted only by the hydraulic operation , and the operation unit can be simplified and downsized.
Further, since a friction load or the like applied to the operation unit is reduced, it is very advantageous also in terms of parts durability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Discharge side passage, 2 ... Valve accommodation room, 4 ... Drain hole, 12
... On-off valve (pressure adjusting means), 19 ... Movable cylinder, 22
... working pressure chamber, 23 ... through-hole, 24 ... valve element, 25 ... sp
Ring, 28 ... Pressure introduction path (pressure adjusting means) .

Claims (1)

(57) [Scope of request for utility model registration] A valve chamber provided in communication with a discharge-side passage of a pump circuit; a drain hole provided in the valve chamber; and a through-hole constantly communicating with the drain hole in a peripheral wall; It is slidably installed in the accommodation room and operates itself forward and backward
A movable cylinder defining a working pressure chamber to the valve accommodating chamber for slidably decorated in該可Do cylinder, the through-hole while that will be spring loaded in the direction of closing the through hole
An oil relief device comprising: a valve body that receives a pressure of a discharge-side passage in a direction in which the opening is opened ; and a pressure adjusting unit that is connected to the operating pressure chamber and adjusts a pressure of the operating pressure chamber.