JPH0560250A - Pressure control valve - Google Patents

Abstract

PURPOSE:To minimize the pulsation of a control liquid pressure, reduce the temperature dependency of liquid pressure control, and improve liquid pressure controllability in a pressure control valve to which the output of a duty valve is inputted. CONSTITUTION:Notches 12c, 12d are formed on respective edge parts on a liquid chamber 14 side of a major diameter land part 12a and a minor diameter land part 12b, respectively. The forms and number of the notches 12c, 12b are set so that the flow rate of the liquid leaked from a feed pressure port 17 to the liquid chamber 14 through the space between the edge part on the liquid chamber 14 side of the minor diameter land part 125 and a housing 13 is nearly coincident with the flow rate of the liquid leaked from the liquid chamber 14 to a drain port 15 through the space between the edge part on the liquid chamber 14 side of the major diameter land part 12a and the housing 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control valve, and more particularly to a pressure control valve for inputting a command signal hydraulic pressure obtained by pulse width modulation control of a high speed ON / OFF solenoid.

[0002]

2. Description of the Related Art Conventional high-speed ON / OFF solenoid (hereinafter referred to as a duty valve) pulse width modulation (hereinafter referred to as P)
As a pressure control valve for inputting a command signal hydraulic pressure obtained by control (for example, WM), for example, “electronically controlled 4-stage automatic transmission” Mitsubishi Heavy Industries Technical Report VOL.21, N
The one described in O.1 is known and is shown as in FIGS.

In FIG. 8, the pressure control valve 1 is a spool 2
And a housing 3, and the spool 2 has a large diameter land portion 2a and a small diameter land portion 2b. A command signal hydraulic pressure P _SIG obtained by PWM control of the duty valve 4 acts on the end surface of the large diameter land portion 2a. The control pressure port 6 opens in the liquid chamber 5 defined by the large diameter land portion 2a and the small diameter land portion 2b, and the supply pressure port 7 and the drain port 8 can be opened in the liquid chamber 5 according to the movement of the spool 2. is there. The line hydraulic pressure P _L is supplied to the supply pressure port 7, the spool 2 is balanced according to each hydraulic pressure acting on the spool 2, and the control hydraulic pressure P _C is supplied to each friction element or the like through the control pressure port 6. It

[0004]

However, in such a conventional pressure control valve, the pulsation of the control hydraulic pressure becomes large or the temperature dependence of the hydraulic pressure control depends on the following reasons. However, there is a problem that the hydraulic pressure control performance is deteriorated due to the increase in the pressure. That is, a region where both the supply pressure port 7 and the drain port 8 do not open to the liquid chamber 5,
Specifically, in the region where the spool 2 is located between the position shown by the solid line and the position shown by the phantom line in FIG. 9 (hereinafter referred to as the overlap region), the sensitivity of the liquid flow rate in and out of the liquid chamber 5 (flow rate gain). ) Indicates a large diameter land portion 2a and a small diameter land portion 2b
It is determined by the gap between the respective edge portions on the liquid chamber 5 side and the housing 3. Therefore, in the overlap area, as shown in FIG.
As shown in, the flow gain is very small. This Figure 1
0 represents the sensitivity (flow gain) characteristic of entry and exit of the liquid flow in the liquid chamber 5, the horizontal axis represents the flow rate Q _L of the liquid position X of the spool 2, the vertical axis to and from the flow into the liquid chamber 5, Let the overlap dimension be ΔL. When the flow gain is small in this way, when the rigidity of the load connected to the control pressure port 6 is low,
The hydraulic pressure cannot be adjusted in the overlap area. Further, in the above-described configuration, the liquid chamber 5 of the small diameter land portion 2b is formed.
The flow rate of the liquid leaking from the supply pressure port 7 to the liquid chamber 5 between the edge portion on the side and the housing 3 depends on the liquid chamber 5 of the large diameter land portion 2a.
Since it is smaller than the flow rate of the liquid leaking from the liquid chamber 5 to the drain port 8 between the side edge portion and the housing 3, the flow rate gain is not point-symmetrical at point A in FIG. 10 in the overlap region. In this case, the equilibrium position of the spool 2 for adjusting the control hydraulic pressure P _C easily becomes unstable. Meanwhile, spool 2
When the position of is out of the overlap region, the flow rate gain becomes very high this time, so the spool 2 does not balance at the equilibrium position, and always moves left and right repeatedly. As a result, a large pulsation occurs in the control hydraulic pressure P _C output from the control pressure port 6. Further, the liquid in the liquid chamber 5 constantly flows in and out due to the repeated movement of the spool 2,
The liquid pressure control is easily affected by the change in the liquid temperature, and the temperature dependency becomes high.

Therefore, according to the present invention, a cutout is formed in at least one of the edge portion of each land portion and each of the supply and drain ports, and the small diameter land portion is passed between the edge portion on the liquid chamber side and the housing. By making the flow rate of the liquid leaking from the supply pressure port into the liquid chamber and the flow rate of the liquid leaking from the liquid chamber to the drain port through the space between the edge of the large diameter land on the liquid chamber side and the housing approximately equal, It is an object to improve the hydraulic pressure control performance by reducing the temperature pulsation of the hydraulic pressure control while reducing the pulsation of.

[0006]

In order to solve the above problems, the present invention comprises a stepped spool having a large diameter land portion and a small diameter land portion, and a housing for accommodating the spool so as to be movable in the axial direction. The large-diameter land portion and the small-diameter land portion face each other and the housing to define a liquid chamber, and a drain port that can be opened to the liquid chamber according to the movement of the spool, and a control pressure that is constantly opened to the liquid chamber. A supply pressure port that can be opened to the liquid chamber according to the movement of the port and a predetermined supply hydraulic pressure is formed in the housing in order from the large diameter land side to the small diameter land side, and high speed ON / OFF The command signal hydraulic pressure obtained by the pulse width modulation control of the solenoid acts on the end surface of the large diameter land on the opposite side of the liquid chamber, and the supply pressure port and drain port are moved to the liquid chamber according to the command signal hydraulic pressure. In the pressure control valve in which the hydraulic pressure in the liquid chamber is regulated and is output as the control hydraulic pressure through the control pressure port, each of the large-diameter land portion and the small-diameter land portion on the liquid chamber side has an edge portion and a drain port. And a notch is formed in at least one of the opening edge of the supply pressure port on the control pressure port side and leaks from the supply pressure port to the liquid chamber through the space between the edge of the small diameter land portion on the liquid chamber side and the housing. The shape and number of the cutouts are set so that the flow rate of the liquid and the flow rate of the liquid leaking from the liquid chamber to the drain port through the space between the edge of the large diameter land on the liquid chamber side and the housing are substantially the same. It is characterized by that.

[0007]

In the present invention, due to the formation of the notch, the flow rate gain becomes large in the spool moving range when both the supply pressure port and the drain port do not open to the liquid chamber,
Also, by making the outflow leakage flow rate of the liquid chamber approximately the same,
The flow gain has point symmetry at the midpoint of the overlap area.
Therefore, the repeated movement of the spool is suppressed,
The spool quickly balances at the equilibrium position.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 7 are views showing an embodiment of the pressure control valve according to the present invention. First, the configuration will be described. 1 to 5,
Reference numeral 11 is a pressure control valve, and the pressure control valve 11 includes a stepped spool 12 and a housing 13. The spool 12 has a large diameter land portion 12a and a small diameter land portion 12b, and a housing 13 houses the spool 12 so as to be movable in the axial direction. Reference numeral 14 denotes a liquid chamber, and the liquid chamber 14 is defined by the housing 13 and the surfaces of the large diameter land portion 12a and the small diameter land portion 12b which face each other. A drain port 15, a control pressure port 16, and a supply pressure port 17 are sequentially formed in the housing 13 from the large diameter land portion 12a side toward the small diameter land portion 12b side. The control pressure port 16 is always open to the liquid chamber 14, and the supply pressure port 17
And the drain port 15 is a liquid chamber according to the movement of the spool 12.
It can be opened to 14. That is, when the spool 12 moves in the direction of arrow E in FIG. 1, the supply pressure port 17 opens in the liquid chamber 14, and when the spool 12 moves in the direction of arrow F in FIG. 1, the drain port 15 opens in the liquid chamber 14. .. Also, supply pressure port 17
A supply liquid pressure (line pressure) P _L is supplied to. 18 is a duty valve, and the duty valve 18 is a command signal hydraulic pressure P.
Output _SIG . Command signal hydraulic pressure P _SIG is high speed ON / OFF
The signal obtained by PWM control of the solenoid, and the hydraulic pressure characteristic of P _SIG with respect to the duty ratio is shown in FIG. The command signal hydraulic pressure P _SIG is applied to the hydraulic passage 19 and the port 20.
And acts on the end surface of the large diameter land portion 12a opposite to the liquid chamber 14.

The spool 1 by the action of the command signal hydraulic pressure P _SIG
When 2 moves in the direction of arrow E in FIG. 1, that is,
When a load having a size of (P _SIG ) × (area of large-diameter land portion) moves the spool 12 against the urging force of the spring 21, the supply pressure port 17 opens in the liquid chamber 14, and the supply liquid pressure is increased. P _L flows into the liquid chamber 14 through the supply pressure port 17, and the large diameter land portion
The hydraulic pressure in the liquid chamber 14 corresponding to the pressure receiving area difference between the small diameter land 12b and the small diameter land 12b causes the command signal hydraulic pressure P _SIG via the large diameter land 12a.
To counter. When the fluid pressure in the fluid chamber 14 rises to exceed the command signal fluid pressure P _SIG and the spool 12 moves in the direction of arrow F in FIG. 1, that is, (the fluid pressure in the fluid chamber 14) × (large diameter When a load having a magnitude (area difference between the land portion and the small diameter land portion) cooperates with the urging force of the spring 21 to move the spool 12 against the command signal hydraulic pressure P _SIG , the drain port 15 causes the liquid chamber to move.
The hydraulic pressure in the liquid chamber 14 is drained through the drain port 15 by opening at 14. As a result, the command signal hydraulic pressure P _SIG causes the spool 12 to move in the direction of arrow E in FIG.
The spool 12 is balanced at a position where the load that tries to move 12 in the direction of arrow F in FIG. 1 is balanced. That is, the drain port 15 and the supply pressure port 17 are opened to the liquid chamber 14 according to the command signal hydraulic pressure P _SIG , the hydraulic pressure in the liquid chamber 14 is regulated, and the control hydraulic pressure P _C is passed through the control pressure port 16. For example, it is output to a clutch piston portion (not shown).

Large diameter land portion 12a and small diameter land portion 12b
Notches 12c, 12 on the respective edge portions on the liquid chamber 14 side of
d is formed. Here, the liquid chamber of the small diameter land portion 12b
The flow rate of the liquid leaking from the supply pressure port 17 into the liquid chamber 14 through the edge portion on the 14 side and the housing 13, and the large diameter land portion 12a.
Through the edge of the liquid chamber 14 side of the housing and the housing 13
The shapes and the numbers of the notches 12c and 12d are set so that the flow rate of the liquid leaking from the drain port 15 to the drain port 15 is substantially the same. In this embodiment, the shapes of the cutouts 12c and 12d are made substantially the same, and the number of the cutouts 12c is set to 2 and the number of the cutouts 12d is set to 4 as shown in FIGS. Reference numeral 31 in FIG. 1 is a pressure reducing valve, and this pressure reducing valve 31 supplies a constant hydraulic pressure to the duty valve 18.

Next, the operation will be described. When the spool 12 is located in the overlap area where neither the drain port 15 nor the supply pressure port 17 is open to the liquid chamber 14, the cutout 12c,
Due to the formation of 12d, the amount of liquid leakage between the edge of each land and the housing 13 increases, and as shown in FIG. 6, the flow rate gain increases as compared with the conventional one having no notch. FIG. 6 shows the sensitivity (flow rate gain) characteristic of the liquid flow rate in and out of the liquid chamber 14, where the horizontal axis is the position X of the spool 12 and the vertical axis is the liquid chamber 14.
Flow rate Q _L, ΔL is overlap dimensions of the liquid to flow in and out to,
The solid line graph in FIG. 6 shows the present embodiment, and the broken line graph shows the conventional flow gain. Further, in this embodiment, the notch 12
By adjusting the numbers of c and 12d, the inflow leakage amount and the outflow leakage amount are substantially equal to each other. Therefore, assuming that the midpoint of the overlap dimension ΔL is A point, the flow gain in the overlap region is point symmetric at A point. ..

As described above, in the present embodiment, the flow gain in the overlap region increases, so that the load connected to the control pressure port 16 is not affected by the rigidity of the load connected to the control pressure port 16 even in the overlap region. The liquid pressure in the liquid chamber 14 can be adjusted. Therefore, it is possible to reduce the repetition of the movement of the spool, quickly balance the spool at the equilibrium position in the overlap region, and reduce the pulsation generated in the control hydraulic pressure P _C. Further, since the inflow leakage amount and the outflow leakage amount of the liquid chamber 14 are made substantially equal to each other, the flow rate gain can be made point symmetrical in the overlap region, and the repetition of the spool movement can be minimized,
The spools can be balanced more quickly in the overlap area. Furthermore, by reducing the repetition of the movement of the spool, it is possible to reduce the inflow and outflow of the liquid in the liquid chamber 14, and it is possible to suppress the adjustment of the liquid pressure 14 from being affected by the change in the liquid temperature, The temperature dependence of the hydraulic control can be reduced. With the above effects, the hydraulic pressure control performance can be improved in this embodiment.

On the other hand, in this embodiment, the notch shape is the same and the inflow and outflow flow rates are made equal by the difference in the number. However, the notch shape, that is, the notch angle, length or size. The inflow leak flow rate and the outflow leak flow rate may be made to coincide with each other by appropriately setting the height and the like. Further, in the present embodiment, the notches are formed at the respective edges of the large diameter land portion 12a and the small diameter land portion 12b, but as shown in FIG. 7, the drain port 15 and the supply pressure port 17 on the control pressure port 16 side respectively. The notches 15a and 17a may be formed in the opening edge portion of the above. In the example shown in FIG. 7, the leak flow rates are matched by making the area of the notch 17a larger than the area of the notch 15a. Further, they may be formed on both the land portion, the drain, and the supply pressure port.

[0014]

According to the present invention, since the notches are formed in the liquid leakage portions of the liquid chamber and the supply / drain port, and the inflow leakage flow rate and the outflow leakage flow rate are substantially the same, the overlap area is provided. Since it is possible to increase the flow rate gain and to make point symmetry, it is possible to reduce the repetition of movement of the spool and quickly balance the spool at the equilibrium position in the overlap region. Therefore,
It is possible to reduce the pulsation of the control hydraulic pressure, reduce the temperature dependence of the hydraulic control, and improve the hydraulic control performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a hydraulic circuit to which an embodiment of a pressure control valve according to the present invention is applied.

FIG. 2 is a diagram showing output characteristics of the duty valve of FIG.

3A and 3B are views showing cutouts of a large-diameter land portion of the spool of FIG. 1, FIG. 3A is a view of the large-diameter land portion viewed from an axial direction, and FIG. 3B is a YY arrow in FIG. FIG.

4A and 4B are views showing cutouts of a small-diameter land portion of the spool of FIG. 1, FIG. 4A is a view of the small-diameter land portion as seen from an axial direction, and FIG. 4B is a cross-sectional view taken along line ZZ in FIG. It is a figure.

5 is a cross-sectional view of essential parts of the pressure control valve of FIG.

6 is a diagram showing sensitivity characteristics of the pressure control valve of FIG.

FIG. 7 is a diagram showing an example of a case where a cutout is formed in the opening edge portions of the supply port and the drain port in FIG. 1, and the opening edge portions of each port are viewed from the spool side.

FIG. 8 is a diagram showing a hydraulic circuit to which a conventional pressure control valve is applied.

9 is a cross-sectional view of main parts of the pressure control valve of FIG.

10 is a diagram showing sensitivity characteristics of the pressure control valve of FIG.

[Explanation of symbols]

12 Spool 12a Large diameter land 12b Small diameter land 12c, 12d, 15a, 17a Notch 13 Housing 14 Fluid chamber 15 Drain port 16 Control pressure port 17 Supply pressure port P _SIG Command signal fluid pressure P _L Supply fluid pressure P _C control Hydraulic pressure

Claims (1)

[Claims] 1. A stepped spool having a large diameter land portion and a small diameter land portion, and a housing for accommodating the spool so as to be movable in the axial direction.
The liquid chamber is defined by the facing surfaces of the large and small lands and the housing, and the drain port that can open to the liquid chamber according to the movement of the spool and the control that constantly opens the liquid chamber A pressure port and a supply pressure port which is supplied with a predetermined supply liquid pressure and can be opened in the liquid chamber according to the movement of the spool are sequentially formed in the housing from the large diameter land portion side toward the small diameter land portion side, and high speed ON / The command signal hydraulic pressure obtained by pulse width modulation control of the OFF solenoid acts on the end surface of the large diameter land on the opposite side of the liquid chamber, and the supply pressure port and drain port open in the liquid chamber according to the command signal hydraulic pressure. In the pressure control valve in which the hydraulic pressure in the liquid chamber is regulated and is output as a control hydraulic pressure through the control pressure port, the large-diameter land portion and the small-diameter land portion have respective edge portions on the liquid chamber side and a drain port. Notch is formed in at least one of the opening on the control pressure port side of the supply pressure port and the supply pressure port, and the cutout is formed between the edge of the small diameter land on the liquid chamber side and the housing. The shape and number of the cutouts are set so that the flow rate of the liquid leaking to the drain port and the flow rate of the liquid leaking from the liquid chamber to the drain port through the space between the edge of the large diameter land on the liquid chamber side and the housing are substantially the same. A pressure control valve characterized by being set.