JPH0849780A - Flow control valve - Google Patents

Abstract

PURPOSE:To provide a flow control valve without the large fluctuation of flow in consequence of the viscosity change of a fluid caused by temperature change and at the same time without the dispersion of flow control performance. CONSTITUTION:A variable orifice 11 is formed by making a rod 9 face one end of an oil passage 5a formed in a plunger 5. The plunger 5 moves in a sleeve, and the opening area of the insert part of the rod 9 and oil passage 5a is changed according to the movement of the plunger 5 to make the quantity of flow fluctuate. In such a flow control valve, the insert part opening edge of the oil passage 5a is formed into sharp-edged cross section so as to form this variable orifice into a sharp-edged orifice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve used in a vehicle power steering device or the like.

[0002]

2. Description of the Related Art A flow control valve used in a vehicle power steering system or the like, and more particularly, a drive torque control valve of a hydraulic pump and a control valve having improved control performance, are disclosed in Japanese Patent Application No. Hei 5-132646. There are some suggestions in the issue. FIG. 6 shows this conventional control valve. As shown in FIG. 6, the conventional control valve is provided in the housing 1.
While forming the pump port P and the tank port T,
The plunger 5 is slidably incorporated. This plunger 5
An oil passage 5a is formed inside. Further, by fixing the rod 9 having the large diameter portion 9b and the small diameter portion 9a on the housing 1 side and inserting the tip of the small diameter portion of the rod 9 into the oil passage 5a, the insertion portion can be changed. Orifice 11
Is formed. Therefore, when the plunger 5 moves in the sleeve 3, the opening area of the variable orifice 11 changes according to the moving amount.

While a spool 16 is provided in the housing 1, a spring chamber 18 is formed on the right side of the drawing by the spool 16 and the housing 1 being combined. A spring 17 is provided in the spring chamber 18 to apply the spring force to the spool 16. Further, the passage 22 guides the pressure oil after the variable orifice into the spring chamber 18. Also, inside the spool 16,
A relief valve including a ball 20 and a spring 21 is provided.

Now, the pressure oil supplied from a hydraulic pump (not shown) flows into the oil passage 5a in the plunger 5 through the pump port P. Further, it flows into the hole 6a of the end plug 6 through the variable orifice 11 and is supplied to the power steering device side (not shown) from there. At that time, a differential pressure is generated before and after the variable orifice 11, and the acting force due to this differential pressure causes the plunger 5 to move to the coil spring 7
It acts as a thrust to move to the left in the figure against the spring force of. The thrust force for moving the plunger 5 in the same direction is not only the above-mentioned differential pressure, but also the acting force of the pressure oil introduced into the pressure chamber 13 via the damping orifice 15.

The differential pressure across the variable orifice 11 is determined by the opening of the spool 16. A portion of the pressure oil after the variable orifice 11, that is, the oil supplied to the power steering device, passes through the passage 22 and the spring chamber 1
Since the pressure difference between the variable orifice 11 and the variable orifice 11 is equal to the differential pressure before and after the variable orifice 11, Therefore, when the differential pressure increases, the spool 16 moves in the right direction in the figure against the spring force of the spring 17. In this way, when the spool 16 moves by the specified stroke, the pump port P communicates with the tank port T, and the oil is returned to the tank. The spool 16 balances at a position where the acting force of the pressure oil on the pump port P side becomes equal to the resultant force of the spring force of the spring 17 and the acting force of the pressure oil in the spring chamber 18.

As described above, according to the moving amount of the spool 16, that is, the pump rotation speed, the variable orifice 1
The differential pressure around 1 changes. Due to this pressure difference, when the plunger 5 moves to the left in the figure, the plunger 5 moves to the large diameter portion 9b of the rod 9, thereby reducing the opening area of the variable orifice 11 and reducing the power steering device side. The flow rate of the pressure oil supplied to is controlled. Further, the hydraulic pressure supplied to the power steering device (not shown) is equal to the hydraulic pressure in the spring chamber 18, and this oil pushes the ball 20 through the filter 19. Then, when the hydraulic pressure becomes larger than the hydraulic pressure set by the spring 21, the oil pushes open the ball 20 and returns to the tank port T. In this way, the oil pressure of the supplied oil is controlled by the relief valve in the spool 16.

[0007]

In the above apparatus, the variable orifice constituted by the plunger and the rod has a large orifice width with respect to its opening area. As described above, when the orifice width becomes larger than the opening area, there is a problem that the change in oil viscosity due to the temperature change is more affected, and even if the opening area is the same, the flow rate fluctuation due to the temperature change becomes large. It was Further, in the above device, when the opening edge of the oil passage in the plunger and the rod are eccentric when assembled, even if the opening area is the same, the flow rate fluctuates if the eccentricity is different, and the product flow rate control Performance will vary.

[0008]

A first aspect of the present invention includes a housing, a sleeve provided in the housing, and an oil passage slidably accommodated in the sleeve and penetrating along the axis. A plunger formed, a pump port formed in the housing and directly communicating with one end of the oil passage, and a spring provided at the end opposite to the one end of the oil passage to urge the plunger. A pressure chamber that is formed between the plunger and the sleeve and that introduces the pressure of the pump port, and is fixed to the housing side,
In addition, a rod having a large diameter portion and a small diameter portion is provided, and by making the tip of the small diameter portion side of this rod face the oil passage of the plunger, a variable orifice is formed in the insertion portion, and the hydraulic pressure in front of this variable orifice is increased. According to the difference between the resultant force of the acting forces on the pressure chamber and the end face of the plunger by the spring, and the resultant force of the spring force of the spring and the hydraulic force after the variable orifice.
It is assumed that the flow control valve is configured so that the plunger moves and the opening area of the variable orifice changes. On the premise of the above apparatus, the variable orifice is characterized in that the cross section of the opening edge of the rod insertion portion of the oil passage in the plunger is formed into a thin blade shape to form a thin blade orifice. A second invention is characterized in that, in the first invention, a thin blade orifice is formed by fitting a thin plate having a rod insertion hole formed in an opening edge of an insertion portion of a plunger.

[0009]

According to the first aspect of the invention, since the opening edge of the oil passage in the plunger has a thin blade shape to form the variable orifice, the orifice width does not increase with respect to the opening area. . Similarly, according to the second aspect of the invention, since the thin blade orifice is formed using the orifice plate, it is possible to obtain the same effect as the above, and it is possible to make the variable orifice thinner. .

[0010]

In the first embodiment shown in FIG. 1, a taper 26 is formed at the opening edge of the rod 9 insertion portion of the oil passage 5a formed in the plunger 5, and the cross section is formed into a thin blade shape. ing. The orifice width h of the thin blade-shaped variable orifice 11 is considerably smaller than the rod insertion hole opening diameter a. In the first embodiment, the rod 9 has a structure in which the small diameter portion 9a and the large diameter portion 9b are inserted into the opening hole of the oil passage 5a. In the second embodiment shown in FIG. 2, the oil passage 5a formed in the plunger 5 is
The orifice plate 23, which is a thin plate, is fitted into the opening edge of the rod 9 insertion portion together with the fixing plate 24, and the left end portion of the plunger 5 is pressed and bent to be caulked. Similar to the first embodiment, since the thickness of the orifice plate 23 is made considerably smaller than the rod insertion hole opening diameter a, the same effect as the thin blade orifice of the first embodiment can be obtained. Further, similarly to the first embodiment, the rod 9 has a configuration in which the small diameter portion 9a and the large diameter portion 9b are inserted into the opening holes of the oil passage 5.

In the third embodiment shown in FIG. 3, the diameter of the large diameter portion 9b of the rod 9 is larger than the opening diameter a. Also in this case, when the small diameter portion 9a is inserted into the oil passage 5a and the plunger 5 approaches the large diameter portion 9b,
Since the flow rate is further reduced, it functions as a variable orifice. Further, the shape of the rod 9 may be tapered so that the diameter of the rod 9 continuously changes, as in the fourth embodiment shown in FIG. Of course, the shape of the rod 9 shown in the third and fourth embodiments may be used in the second embodiment in which the orifice plate 23 is provided to form the variable orifice.

Further, as shown in FIG.
If the adjusting orifice 25 corresponding to the notch is formed, finer flow rate control becomes possible.

[0013]

According to the first aspect of the invention, since the variable orifice has a thin blade shape, the orifice width becomes smaller than the opening area. Therefore, it is less affected by the change in oil viscosity due to temperature change, and fluctuations in the flow rate due to temperature can be reduced. In addition, even when the opening edge of the oil passage in the plunger and the rod are eccentrically assembled, even when both are assembled concentrically or when the eccentricity is different from the above, The difference in the flow rate is small, and it is possible to reduce the variation in the flow rate control. Therefore, it is possible to reduce the variation in the flow rate control performance for each product. According to the second invention, since the thin blade orifice is formed by using the orifice plate, the same effect as that of the first invention can be obtained.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment, and is a main part view of a flow control valve of the present invention.

FIG. 2 is a view showing a second embodiment and is a main part view of a flow control valve of the present invention.

FIG. 3 is a diagram showing a third embodiment and is an enlarged view of a main part diagram.

FIG. 4 is a view showing a fourth embodiment and is an enlarged view of a main part diagram.

5A and 5B are views showing a control valve of the present invention, FIG. 5B is an enlarged view of a main part view, and FIG. 5A is a view of the adjusting orifice 25 seen from above.

FIG. 6 is a sectional view of a conventional flow control valve.

[Explanation of symbols]

 5 Plunger 5a Oil passage 9 Rod 9a Small diameter part 9b Large diameter part 11 Variable orifice 23 Orifice plate 24 Fixed plate 25 Adjusting orifice 26 Taper

Claims (2)

[Claims] 1. A housing, a sleeve mounted in the housing, a plunger that is slidably accommodated in the sleeve and that forms an oil passage that penetrates along the axis, and the housing. Formed between the pump port that is formed and directly communicates with one end of the oil passage, the spring that is provided at the end opposite to the one end of the oil passage and that biases the plunger, and the plunger and the sleeve. The pressure chamber for introducing the pressure of the pump port and the rod fixed to the housing side and having the large diameter portion and the small diameter portion are provided, and the tip of the small diameter portion side of the rod is placed in the oil passage of the plunger. As a result, a variable orifice is formed in the insertion portion, and the resultant force of the hydraulic pressure before the variable orifice exerts on the pressure chamber and the end face of the plunger and the spring force of the spring. In the flow control valve configured such that the plunger moves and the opening area of the variable orifice changes according to the difference between the resultant force of the hydraulic pressure after the variable orifice and the resultant force of the oil passage in the plunger. A flow control valve characterized in that a thin blade orifice is formed by making the cross section of the opening edge of the rod insertion portion into a thin blade shape. 2. The flow rate control valve according to claim 1, wherein a thin blade orifice is formed by fitting a thin plate having a rod insertion hole formed in the opening edge of the insertion portion of the plunger.