JPH0482A - Proportional solenoid valve - Google Patents

Abstract

PURPOSE:To reduce an axial fluid force to improve the control accuracy for fluid pressure by inserting a radial plate in a part in the vicinity of discharge port inside a sleeve between an opening/closing land part and non-opening/ closing land part. CONSTITUTION:In a part in the vicinity of a discharge port 7 inside a sleeve between an opening/closing land part 3b and non-opening/closing land part 3a, a radial plate 9 is inserted, and then the flow-out angle of fluid becomes large. As a result, axial force Fs caused by fluid force becomes small. In a conventional device in which such a plate 9 is not inserted, fluid flows along the inner surface of a sleeve 2 and flows in a discharge port 7, and thereby a flow-out angle theta becomes small while the axial force of fluid pressure becomes large. By inserting the plate 9 in a part in the vicinity of the discharge port 7, however, fluid flows in the vicinity of the center of a spool 3, and flows out with the large flowing angle theta toward the discharge port 7 from the vicinity of the center of the spool 3. As a result the axial force Fs caused by fluid force becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a proportional solenoid valve used in fluid control equipment, particularly hydraulic control equipment for automatic transmissions of automobiles.

[Conventional technology]

FIG. 8 is a sectional view showing a conventional proportional solenoid valve of this type. In the figure, the spool 3 has an opening/closing land portion 3b that opens and closes the discharge port 7, a non-opening/closing land portion 3a of the same diameter provided opposite to this opening/closing land portion 3b, and a diameter larger than both land portions 3a, 3b. It has a small feedback land portion 3c, and when this Subur 3 slides inside the sleeve 2, the discharge port 7 is opened at the opening/closing land portion 3b.
is opened and closed to adjust the pressure of fluid flowing in from the input port. That is, fluid at a predetermined pressure supplied from a pump or the like (not shown) flows from the input port into the non-openable land portion 3a and the openable land portion 3b in the sleeve 2, and the pressure at the place where it flows is increased. It is adjusted by the degree of opening and closing of the discharge port 7.

Here, the degree of opening and closing of the discharge port 7 is determined by the solenoid 1.
The electromagnetic pressing force (F, ) generated by the spring 4, the spring force (F, ) caused by the spring 4, and the feedback force (F, ) due to the difference in the axial cross-sectional area of the non-openable land portion 3a and the feedback land portion 3C. A fluid pressure determined by the balance of forces and proportional to the energizing current supplied to the solenoid 1 is obtained.

In other words, the electromagnetic pressing force (F, , ) presses the spool 3 in the left direction in the figure via the rod 5, and has a magnitude approximately proportional to the applied current. The spring force (F,) is a force that presses the spool 3 in the right direction in the figure, and the feedback force (F
p (proportional to control pressure) is a force acting in the left direction in the figure. The balance of the above three forces is as shown in the following equation.

Fm+F, +F*=0 [Problem to be solved by the invention] The conventional proportional solenoid valve is configured as described above, and the axial force due to the fluid force especially near the discharge port 7 is F, = ρQ u
This axial force F, which is given by cos θ, increases as the flow rate Q increases and the outflow angle θ decreases (see FIG. 9). Here ρ
is the density, Q is the flow rate, U is the flow velocity, and θ is the outflow angle.

This axial force F acts on the spool 3 as pressure in the right direction in the figure, and the balance of the above three forces F, +F, +F
, =O, resulting in poor fluid pressure control accuracy.

Moreover, if this axial force F is too large, there is a problem that the spool 3 cannot be controlled by the electromagnetic force generated by the solenoid 1.

This invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a proportional solenoid valve in which the influence of the axial fluid force acting on the spool at the discharge port is small.

[Means to solve the problem]

In the proportional solenoid valve according to the first invention, a radial plate is inserted in the vicinity of the discharge port in the sleeve between the opening/closing land portion and the non-opening/closing land portion in order to reduce the axial fluid force acting on the spool. It is characterized by

The proportional solenoid valve according to the second invention is characterized in that a wall facing the discharge port of the opening/closing land portion of the spool is tapered in the radial direction.

[Effect]

1st. According to the proportional solenoid valve of the second invention, by inserting a plate into the sleeve or by providing a taper in the opening/closing land portion of the spool, the outflow angle of the fluid flowing out from the discharge port approaches 90 degrees, which acts on the spool. Reduce axial fluid force.

〔Example〕

FIG. 1 is a sectional view showing a proportional solenoid valve according to an embodiment of the present invention. In the figure, 1 is a solenoid, 2 is a sleeve, and 3 is a spool that slides inside the sleeve 2. 64 is a spring which has a non-opening/closing land portion 3a, an opening/closing land portion 3b, and a feedback land portion 3C; 5 is a rod that transmits the electromagnetic pressing force generated by the solenoid 1 to the spool 3; and 6 is an input port into which pressurized fluid flows. , 7 is a discharge port opened and closed by the opening/closing land portion 3b, 8 is a feedback circuit, and 9 is a plate introduced in this embodiment. By inserting this plate 9 into the sleeve 2, the fluid force can be reduced. .

That is, when the plate 9 is inserted, the outflow angle θ of the fluid increases as shown in FIG. 2, and as a result, the axial force F, (=ρQ u cos θ) due to the fluid force decreases. That is, in the conventional device in which the plate 9 is not inserted, the fluid flows along the inner surface of the sleeve 2 and directly flows into the discharge port 7, so the outflow angle θ is small and the axial force of the fluid force is large. However, by inserting the plate 9 into the sleeve 2 near the discharge port 7 as in this embodiment, the fluid flows near the center of the spool 3, and the outflow angle θ is large from near the center of the spool 3 toward the discharge port 7. Since the fluid flows out with a force of , the axial force F caused by the fluid force becomes smaller.

FIG. 3 is a front view showing the shape of the plate 9, and FIG. 4 is a sectional view showing how the plate 9 is assembled into the sleeve 2.
After putting the spool 3 and spring 10 into the sleeve 2, the plate 9 is inserted from the bottom of the sleeve 2 (installation is from the surface). FIG. 5 is a sectional view taken along the line -V in FIG. 4, and shows the positional relationship between the plate and the spool when the plate 9 is inserted.

As described above, according to this embodiment, the axial force F of the fluid force can be reduced by inserting the plate 9.
Since the disturbance at F, +Fp+F, =O becomes smaller,
Improves accuracy in controlling pressure. Further, when F becomes smaller, the electromagnetic pressing force F1 generated by the solenoid 1 also becomes smaller, and the solenoid 1 can be made smaller.

FIG. 6 is a sectional view of a proportional solenoid valve showing another embodiment of the present invention.The basic configuration is the same as the conventional example shown in FIG. 8, and the difference from the conventional example is that the discharge port 7 can be opened and closed. The opening/closing land portion 30b is tapered to reduce the axial force F1 due to fluid force.

That is, by tapering the opening/closing land portion 30b, the fluid flows out to the discharge port 7 along the taper, and by changing this taper angle, the fluid outflow angle θ can be increased as shown in FIG. . As a result, the axial force F due to the fluid force becomes smaller.

〔Effect of the invention〕

As described above, according to the present invention, the axial fluid force acting on the spool can be minimized by inserting a plate into the sleeve near the discharge port or tapering the opening/closing land of the spool. The accuracy of fluid pressure control is improved. Also, equipment (especially solenoids)
This has the effect of making it smaller.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a proportional solenoid valve according to an embodiment of the present invention, FIG. 2 is a detailed sectional view of FIG. 1, FIG. 3 is a front view showing the shape of the plate of this embodiment, and FIG. The figure is a sectional view showing how the plate is assembled, FIG. 5 is a sectional view taken along the line ■-V in FIG. 6 is a detailed sectional view, FIG. 8 is a sectional view showing a conventional proportional solenoid valve, and FIG. 9 is a detailed sectional view of FIG. 8. In the figure, 1 is a solenoid, 2 is a sleeve, 3 is a spool, 3a is a non-open/close land, 3b, 30b are open/close lands, 3C is a feedback land, 6 is an input port, 7 is a discharge port, and 9 is a plate. be. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A spool that is slidably installed in the sleeve and has at least an open/close land portion and a non-open/close land portion provided opposite each other, and guides pressure fluid between the open/close land portion and the non-open/close land portion. In a proportional solenoid valve comprising an input port, a discharge port that is opened and closed by the opening/closing land and adjusting the pressure of the pressure fluid, and an electromagnetic pressing means for moving the spool in the axial direction, the opening/closing land and the non-opening/closing A proportional solenoid valve characterized in that a radial plate is inserted near the discharge port in the sleeve between the lands. (2) A spool that is slidably installed within the sleeve and has at least an open/close land portion and a non-open/close land portion provided opposite each other, and guides pressure fluid between the open/close land portion and the non-open/close land portion. In a proportional solenoid valve comprising an input port, a discharge port that is opened and closed by the opening/closing land and adjusting the pressure of the pressure fluid, and an electromagnetic pressing means for moving the spool in the axial direction, the discharge port of the opening/closing land is provided. A proportional solenoid valve characterized by having a radial taper on the wall facing the.