JPH0512512Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to an orifice control valve for a hydraulic control device of an automatic transmission.

(b) Conventional technology As a conventional orifice control valve,
For example, JP-A-58-196373, JP-A-60-
Some examples are shown in Publication No. 81550. The orifice control valve shown in these figures has a land portion with a slightly smaller diameter than the normal sliding land diameter on the spool that fits into the valve hole.
Oil flows through the annular gap between the small-diameter land portion and the valve hole, thereby achieving the function of a throttle valve.

(c) Problems to be solved by the invention However, the conventional orifice control valve as described above has a problem in that the throttling effect lacks stability. That is, even if the dimensional accuracy of the valve hole and the small-diameter land portion of the spool is within an allowable range, the cross-sectional area of the annular gap will vary relatively largely due to dimensional variations, and the throttling effect will vary. Furthermore, if the material on the valve hole side and the material on the spool are different, the coefficient of thermal expansion will be different, and the throttling effect will fluctuate when a temperature change occurs. Furthermore, since the annular gap is formed over a relatively long dimension in the axial direction, it has a configuration similar to a choke valve, and the throttling effect is large depending on the clay of the oil (i.e., the temperature of the oil). fluctuate. The present invention aims to solve these problems.

A conventional technique for constructing an orifice by machining the spool side is to provide an axial hole in the center of the spool and radial holes that communicate with this axial hole from the valleys on both sides of the land. be. However, in this case, machining is troublesome, and the opening end of the axial hole must be sealed with a plug. In addition, since the hole becomes longer, it acts as a choke valve, and as mentioned above, it becomes susceptible to the influence of oil viscosity.

There is also a pressure regulating valve in which a hole is provided in the land of the spool (for example, see Japanese Patent Application No. 61-242007).
This is a system in which a hole is provided in the spool to guide hydraulic pressure for pressure regulating feedback to one end of the spool, without providing a passage on the valve body side. This hole has a diameter that produces a throttling effect in order to prevent hunting during pressure adjustment of the spool. However, this hole is for constantly guiding oil to one end of the spool, and is not for switching an oil path with an orifice, and is unrelated to the present invention.

In addition, "Mechanical Design Series, Design of Fluid Transmission Devices" (published by Ohmsha Co., Ltd.) states that a part of the spool should be chamfered to prevent hunting; This is unrelated to the present invention.

Further, Japanese Utility Model Application Publication No. 60-114356 discloses a pressure regulating valve in which a flat notch is provided over the entire length of the land. This notch acts as a choke valve to constantly drain oil.
This allows the pressure regulation value to change depending on the oil temperature. Since this is also not for switching the orifice, the purpose and operation are different from those of the present application.

Japanese Utility Model Application Publication No. 60-64352 discloses a plug in which a planar notch is provided over the entire length of the plug. This notch is provided only as a passage for oil discharge and has no function as an orifice.

(d) Means for solving the problems The present invention solves the above problems by providing a groove in the land of the spool to create a squeezing effect. That is, the present invention includes a valve hole 12 having first and second ports 12b and 12c adjacent to each other, and a spool 1 inserted into the valve hole 12.
4 and the land 14 provided on this spool 14.
b, an orifice passage provided in the land 14b so that both axial ends thereof communicate with each other, a spring 16 that applies a pressing force to one end of the spool 14, and a spring 16 applied to the other end of the spool 14. It has a pressing means that can switch the spool 14 between a first position and a second position by applying a pressing force in a direction opposite to the pressing direction and changing the magnitude of this pressing force. The first position of the spool 14 is the land 14.
b is located between the first port 12b and the second port 12c, and the orifice passage communicates with both ports, and the second position of the spool 14 is such that the orifice passage does not communicate with both ports 12b and 12c. In the orifice control valve 10 for a hydraulic control device of an automatic transmission configured to There is.

(E) Operation When the spool is in the first position, the first port and the second port communicate with each other through a groove provided in the land. This groove has a throttling effect, and for example, oil flowing from the first port to the second port is subjected to the throttling effect. spool is second
When moved to this position, the first port and the second port are no longer in communication through the groove. As described above, when the spool is in the first position, the groove provided in the land produces a throttling effect, so a stable throttling effect can be obtained. That is, it is not affected by the dimensional accuracy of the valve hole or the spool, nor is it affected by the thermal expansion of the spool, and furthermore, compared to a narrow annular passage, it functions less as a choke valve. This solves the problems of conventional orifice control valves as described above.

(f) Example (first example) Orifice control valve 1 shown in Fig. 1
0 is a valve hole 12 having ports 12a to 12d.
and a spool 14 having lands 14a to 14c.
and a spring 16 that pushes the spool 14 to the right in the figure. Port 12a is a drain port, port 12b (first port) communicates with oil passage 18, and port 12c (second port)
is in communication with the oil passage 20, and the port 12d is in communication with the oil passage 22. Note that the oil passage 18 and the oil passage 20 communicate with each other via an orifice 24.
Lands 14a, 14b and 14c of spool 14
are in the relationship as shown with each port of the valve hole 12, and in the first position shown in FIG. 1, the land 14b is located between the ports 12b and 12c. Furthermore, in the second position of the spool 14 shown in FIG.
4c. The land 14b has a groove 26 (orifice passage) that communicates between both ends of the land 14b.
is provided. The groove 26 has a shape as shown in FIG. The aforementioned oil passage 18 is connected to a shift valve (not shown), and hydraulic pressure is supplied when the shift valve is switched. The oil passage 20 is connected to a hydraulic servo cylinder that operates the brake. A predetermined control signal pressure is supplied to the oil passage 22 . In addition, from the oil passage 22 to the port 12
The control signal pressure acting on d constitutes a pressing means for switching the spool 14.

Next, the operation of this embodiment will be explained. When the control signal pressure supplied from the oil passage 22 to the port 12d is lower than a predetermined value, the spool 14 is pushed by the spring 16 to the first position shown in FIG. In this state, port 12b and port 12
c communicates with each other via groove 26. Since the groove 26 has a small cross-sectional area, it produces a constriction effect.
As a result, the oil passage 18 and the oil passage 20 are connected to each other via the orifice 24 and the groove 26. Therefore, the shift valve switches and the oil passage 18
The hydraulic pressure supplied to the orifice 24 and the groove 2
It is supplied to the oil passage 20 through 6 and acts on the cylinder of the hydraulic servo. Orifice 24 plus groove 2
Since oil is supplied through 6, the hydraulic pressure acting on the cylinder rises relatively quickly.

On the other hand, when the control signal pressure supplied to the oil passage 22 becomes higher than a predetermined value, the spool 14 is pushed by this control signal pressure and switches to the second position shown in FIG. In this second position, the port 12c is connected to the land 14.
blocked by c. Therefore, port 12b
The connection between the port 12c and the port 12c is cut off. In this case, the oil passage 18 and the oil passage 20 are connected only through the orifice 24, and the oil passage 18 is connected to the oil passage 20 through the orifice 24.
The oil pressure supplied to the cylinder 0 and acting on the cylinder will rise slowly.

As described above, the rise state of the oil pressure supplied from the oil passage 18 to the oil passage 20 can be switched depending on the magnitude of the control signal pressure acting on the oil passage 22. As shown in FIG. 3, the groove 26 is a cutout of the land 14b and has a predetermined cross-sectional area. Therefore, even if the diameter of the land 14b and the inner diameter of the valve hole 12 change, the throttling effect of the groove 26 will not be affected. Further, even if the dimensions of the valve hole 12 and the land 14b change due to a change in temperature, the throttling effect of the groove 26 is similarly not affected. Furthermore, the groove 26 has a length dimension (that is, the length dimension of the land 14b).
Since the cross-sectional area is large enough for Therefore, the degree to which the aperture effect fluctuates is extremely small. For these reasons, the throttling effect of the groove 26 becomes very stable, a predetermined throttling effect can be obtained, and the speed change performance can be stabilized.

(Second Embodiment) FIGS. 4 and 5 show a second embodiment of the present invention. In the first embodiment shown in FIGS. 1 and 2, the spool 1
Port 12b and Port 1 when 4 is in the second position
However, in this second embodiment, the port 12b and the port 12c are configured to communicate with each other when the spool 14 is in the second position. That is, the operation in the first position shown in FIG. 4 is similar to that in the first embodiment, but in the second position shown in FIG.
b and port 12c are land 14b and land 14
It communicates with c. Therefore, in the second position, the oil passage 18 and the oil passage 20 are in a connected state without being subjected to the throttling effect. That is, in the case of the second embodiment, it is possible to switch between a state in which a throttling effect is generated by the orifice 24 and the groove 26, and a state in which an oil passage bypassing the throttling effect is formed.

In addition, in the above-mentioned embodiment, the groove 26 is located in the land 1.
Although one groove 26 is provided in the groove 4b, two grooves 26 may be provided as shown in FIG.
As shown in FIGS. and 8, it can have any shape. Further, the axial cross section of the groove 26 can also have any shape, as shown in FIGS. 9 and 10, respectively.

(g) Effects of the invention As explained above, according to the invention, the orifice passage that generates a throttling effect is formed by the groove provided in the land of the spool, so that machining of the spool, valve hole, etc. It is possible to always obtain a stable squeezing effect without being affected by accuracy or changes in oil temperature. That is, since the orifice passage is formed by a groove, the throttling effect hardly changes due to temperature changes even if the coefficient of thermal expansion of the material on the valve hole side and the material of the spool are different. Furthermore, the influence of changes in oil viscosity is also reduced. Furthermore, compared to creating a hole in the land of the spool, the machining process is simple as only a groove is provided on the outer periphery of the land, and there is no restriction due to the size of the land diameter. It can be done. Further, since the throttling effect of the orifice passage can be adjusted by selecting the width and depth of the groove, the degree of freedom is greater than in the case of hole machining. Furthermore, since the grooves are visible, it is easy to identify spools provided with grooves of different sizes.

[Brief explanation of the drawing]

Figure 1 shows that the spool of the first embodiment of the present invention is
FIG. 2 is a diagram showing the spool of the first embodiment in the second stop position, FIG. 3 is a sectional view taken along the - line in FIG. 1, and FIG. FIG. 5 is a diagram showing the spool of the second embodiment of the present invention in the first stop position, FIG. 6 is a diagram showing the spool of the second embodiment in the second stop position, and FIG. FIGS. 7 and 8 are views showing spools provided at different locations, FIGS. 7 and 8 are views showing spools with grooves having different cross-sectional shapes, and FIGS. 9 and 10 are views showing spools with grooves having different axial cross-sectional shapes. 10... Orifice control valve, 12
... Valve hole, 12b ... Port (first port), 1
2c...port (second port), 14...spool, 14b...land, 26...groove (orifice passage).

Claims (1)

[Claims for Utility Model Registration] A valve hole having first and second ports adjacent to each other, a spool inserted into the valve hole, a land provided on the spool, and both axial ends of the land provided on the land. An orifice passage provided so that the sides communicate with each other, a spring that applies a pressing force to one end of the spool, a pressing force that applies a pressing force to the other end of the spool in a direction opposite to the pressing direction of the spring, and this pressing force a pressing means capable of switching the spool between a first position and a second position by changing the size of the spool; and the second port, where the orifice passage communicates with both ports, and the second position of the spool is a position where the orifice passage does not communicate with both ports. An orifice control valve for a hydraulic control device of an automatic transmission, characterized in that the orifice passage is formed by a groove formed by cutting out a part of the land.