JP2002122249A - Spool valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of vibration by forming a notch in a spool of a spool valve and suppress the generation of flow force to the minimum extent to stabilize the operation. SOLUTION: A line A forming 69 deg. (maximum value of free flow-in angle ϕf) with the direction of axial line L is drawn by passing a communicating part (a) when the notch 34 formed in a stepped part 28 of the spool 17 is communicated with an input port 13, and the notch 34 is arranged on the left side of the line A. Since the fluid flowing into a groove 22 from the communicating part (a) when the notch 34 of the spool 17 is communicated with the input port 13 does not collide against the other part of the spool 17 until it collides against a bottom part of the groove 22, the flow in the direction of axial line L of the fluid causing flow force Fo acting on the spool 17 is suppressed to the minimum extent, and a load of an actuator 26 is reduced. Consequently, stable operation of the spool valve becomes possible while preventing self-excited vibration of the spool 17 by the action of the notch 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spool valve having a notch at a step between a land and a groove of a spool.

[0002]

2. Description of the Related Art Such a spool valve is disclosed in Japanese Utility Model Registration No. 2569681 and Utility Model Registration No. 2580.
No. 463, which is publicly known.

FIGS. 8 and 9 show the structure of a conventional spool valve for pressure control.
The input port 13, the output port 14, the drain port 15, and the feedback port 16 are opened in the valve hole 12 having a circular cross section formed at a distance in the direction of the axis L. The spool 17 slidably fitted in the valve hole 12 of the valve housing 11 includes a first land 18, a second land 19, a third land 20, and a spring seat 21 projecting to the left of the third land 20. , A first groove 22 formed between the first land 18 and the second land 19, a second groove 23 formed between the first land 18 and the third land 20, and a right side of the second land 19. A solenoid connection unit 24. The spool 17 is provided between the end of the valve hole 12 and the spring seat 21.
5, it is urged rightward and coaxially abuts the left end of the output rod 27 of the direct acting linear solenoid 26 that directly operates the spool 17.

The first groove 22 of the spool 17 has an axis L
Is connected to the right end of the first land 18 via a first step 28 perpendicular to the axis L, and is connected to the left end of the second land 19 via a second step 29 perpendicular to the axis L. First
A predetermined number (for example, four) of notches 30 are formed in the step portion 28.
It consists of a chamfer inclined at 0 °. And spool 17
Is in the illustrated position, the input port 13 is in communication with the output port 14 via the first groove 22, and when the spool 17 moves to the right, the communication between the input port 13 and the first groove 22 is interrupted. , The output port 14 is the first groove 2
2 and to the drain port 15. The feedback port 16 is provided in the oil chamber 31 on the left side of the third land 20.
A feedback pressure acts through the first land 18 and the third land 20, and an oil chamber 32 formed between the first land 18 and the third land 20 has an oil hole formed to connect the first groove 22 and the second groove 23 to the spool 17. It communicates via 33.

In the spool valve having the above structure, when the linear solenoid 26 is excited to drive the output rod 27 to the left and press the right end of the spool 17 against the resilience of the valve spring 25, the input port 13 is turned on. The output port 14 communicates with the output port 14 via the first groove 22, and the hydraulic pressure of the input port 13 is reduced according to the opening degree of the output port 1.
4 is output. At this time, the action of the notch 30 formed in the first step portion 28 connected to the first land 18 reduces the amount of pressure change of the output port 14 with respect to the amount of position change of the spool 17 and suppresses the self-excited vibration of the spool 17. can do.

[0006]

By the way, when the oil supplied from the input port 13 flows into the first groove 22 through the notch 30, the oil flows in the first groove 22 along the axis. It flows in the L direction and collides with the second step portion 29 to generate a flow tooth Fo for urging the spool 17 rightward. Since the flow tooth Fo acts so as to oppose the leftward driving force Fs generated by the linear solenoid 26, there is a problem that the smooth operation of the linear solenoid 26 is hindered and delicate hydraulic control becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a notch formed in a spool to prevent the occurrence of vibration and minimize the occurrence of flow force to stabilize the operation of a spool valve. With the goal.

[0008]

According to the first aspect of the present invention, there is provided a valve housing having a valve hole, and a valve formed in the valve housing so as to be spaced apart in the axial direction. An input port and an output port that open into the hole, a spool that is slidably fitted in the valve hole in the axial direction, a first land and a second land that are formed in the spool so as to be spaced apart in the axial direction, and formed on the spool. A groove connected to the first land and the second land via the first step portion and the second step portion, a notch formed so as to cut out the first step portion, and an actuator for driving the spool in the axial direction. Driving the spool with the actuator to connect the input port to the groove,
In a spool valve that discharges fluid flowing from an input port through an output port through a groove, a line that forms a free inflow angle with respect to the axial direction through a communication portion when a notch of the spool communicates with the input port is first formed. A spool valve characterized in that the spool valve intersects the bottom of the groove.

According to the above construction, when the notch of the spool communicates with the input port, the fluid flowing into the groove from the communicating portion does not collide with the other portion of the spool until it collides with the bottom of the groove. The axial flow of the fluid, which causes the flow force to flow, is minimized and the load on the actuator is reduced. Thereby, while preventing self-excited vibration of the spool by the action of the notch formed in the first step portion, the flow force acting on the spool can be reduced and the spool valve can be operated stably.

According to the second aspect of the present invention,
In addition to the configuration of claim 1, a spool valve is proposed, wherein the free inflow angle is 69 °.

According to the above configuration, the free inflow angle is 69 ° corresponding to the maximum free inflow angle. Therefore, the free inflow angle corresponds to the maximum free inflow angle according to the shape of the notch and the opening of the input port. Even at 69 °, the flow force acting on the spool can be kept small.

According to the invention described in claim 3,
The spool valve according to claim 1 or 2, wherein the notch is formed in a direction orthogonal to an axis in addition to the configuration of claim 1 or 2.

According to the above configuration, since the notch is formed in a direction orthogonal to the axis, the notch can be processed by the end mill, thereby improving workability.

The linear solenoid 26 of the embodiment corresponds to the actuator of the present invention, and the first groove 22 of the embodiment is used.
Corresponds to the groove of the present invention.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 3 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a spool valve, FIG. 2 is a perspective view of a spool, and FIG. 3 is an explanatory view of an inflow angle.

As shown in FIGS. 1 and 2, the spool valve of the first embodiment differs from the conventional spool valve described with reference to FIGS. 8 and 9 in the shape of the notch 34, and other structures are the same. Are identical. Therefore, the same reference numerals are given to the components corresponding to the components of the first embodiment, and the description thereof will not be repeated, and the description will focus on the structure of the notch 34 which is the difference.

The first land 18 and the first land 18 of the spool 17
A predetermined number (for example, four) of notches 34 formed in the first step portion 28 connecting the grooves 22 are formed of partially cylindrical cutouts extending in a direction perpendicular to the axis L, and both ends thereof are the first notches. The outer peripheral surface of the land 18 and the outer peripheral surface of the first groove 22 are continuous. Since the notch 34 is formed in the direction orthogonal to the axis L as described above, the notch 34 can be processed by the end mill, and the workability is improved.

When the input port 13 is opened, the oil
The angle flowing into the groove 22 is called the flowing angle φ. The inflow angle φ when the oil flows in parallel to the axis L is 0 °
And the inflow angle φ when the oil flows at right angles to the axis L is 90 °. As shown in FIG. 3, the inflow angle φ when both the first step portion 28 having no notch and the input port 13 are formed at an angle of 90 ° with respect to the axis L.
Is called the free inflow angle φf. The free inflow angle φf has a maximum value (φf = 6) as the opening of the input port 13 increases.
9 °). In general, the inflow angle φ when the notch 34 is formed in the first step portion 28 is smaller than the free inflow angle φf when the notch 34 is not provided. Therefore, the inflow angle φ when the notch 34 is formed is Never exceed 69 °. About this inflow angle φ, "Hydraulic control"
It is disclosed in Toshio Takenaka and Eizo Urata (Maruzen Co., Ltd.).

Returning to FIG. 1, the input port 13 passes through the communication portion a when communicating with the first groove 22 and forms an angle of 69 ° (the maximum value of the free inflow angle φf) with respect to the axis L. The shape of the notch 34 is set so that when the line A toward L is drawn, the line A first crosses the bottom of the first groove 22 and does not cross other portions of the spool 17. When the notch 34 is located on the left side of the line A, the inflow angle φ when the input port 13 is opened is
Is the largest, the inflow angle φ is less than 69 °, so that the oil flowing from the input port 13 into the first groove 22 as a jet flows into the bottom of the first groove 22 without being hindered by the notch 34. Can be reached. Since the velocity of the jet that has reached the bottom of the first groove 22 is reduced, even if the jet deflects in the direction of the axis L along the bottom of the first groove 22 and collides with the second step 29,
The generated flow force Fo is suppressed to a small value, and smooth operation of the linear solenoid 26 is ensured.

On the other hand, in the conventional example shown in FIG. 10A, since the angle θ of the notch 30 is 30 ° or 45 ° and projects to the right of the line A, when the input port 13 is opened. The jet flowing into the first groove 22 is guided by the notch 30 and is forcibly deflected rightward in the direction of the axis L, and strongly collides with the second step portion 29 to generate a large flow force Fo. FIG. 10 (B)
In the conventional example shown in FIG. 1, the angle of the tip of the notch 30 is a right angle and fits on the left side of the line A. However, since the step 30a of the notch 30 extending in the direction of the axis L projects to the right of the line A, The jet flow when the input port 13 is opened is guided to the step 30a of the notch 30, and the axis L is forcibly forced.
Is deflected to the right. At this time, the step 3 of the notch 30
Since the distance between Oa and the input port 13 is small, the momentum of the jet deflected rightward also becomes strong, and a large flow force Fo is generated.

Next, a second embodiment of the present invention will be described with reference to FIGS.

The spool valve of the second embodiment is similar to the first groove 22 of the spool 17 of the spool valve of the first embodiment.
The second embodiment is different from the first embodiment in that a concave curved surface 35 is formed in the second embodiment.

According to this embodiment, the oil that has flowed into the first groove 22 as a jet from the input port 13 is guided by the curved surface 35 at the bottom of the first groove 22 and directly collides with the second step portion 29. Without being directed toward the radially outer output port 14. Thus, the flow force Fo by the jet flow is further reduced, and the smooth operation of the linear solenoid 26 is ensured.

Next, the effect of the present invention will be described with reference to FIGS.

FIG. 6 is a graph showing the relationship between the flow rate of the oil flowing from the input port 13 and the oil pressure at the output port 14 in the first graph.
Example, Second Example, Conventional Example (θ = 30 in FIG. 10A)
° and θ = 45 °). The pressure loss is the largest in the conventional example of θ = 30 °, the largest in the conventional example of θ = 45 °, the largest in the first embodiment, and the smallest in the second embodiment.

FIG. 7 is a graph showing the relationship between the time elapsed from the start of energization of the linear solenoid 26 and the rise of the clutch oil pressure when the spool valve is used as a hydraulic control valve of the hydraulic clutch in the first embodiment and the first embodiment. 2 Example, Conventional Example (FIG. 10A)
= 45 °). The rise of the clutch hydraulic pressure is the fastest in the second embodiment, then fast in the first embodiment, then fast in the conventional example of θ = 45 °,
The conventional example with θ = 30 ° is the slowest.

As described above, according to the first and second embodiments of the present invention, the flow force Fo can be effectively reduced, so that an extra load is prevented from being applied to the linear solenoid 26. It is possible to reduce the pressure loss and reduce the responsiveness of the pressure control. In particular, a large effect can be exerted when a direct-acting linear solenoid 26, which is difficult to generate a large driving force Fs due to a small coil, is used as the actuator.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, the shape of the notch 34 is not limited to the embodiment, but can be changed as appropriate. Further, the spool valve of the present invention can be applied to a valve for any purpose other than the hydraulic control valve.

[0031]

As described above, according to the first aspect of the present invention, when the notch of the spool communicates with the input port, the fluid flowing into the groove from the communicating portion collides with the bottom of the groove. Does not collide with the rest of the actuator, thereby minimizing the axial flow of fluid causing flow force on the spool and reducing the load on the actuator. Thereby, while preventing self-excited vibration of the spool by the action of the notch formed in the first step portion, the flow force acting on the spool can be reduced and the spool valve can be operated stably.

According to the second aspect of the present invention,
Since the free inflow angle is 69 ° corresponding to the maximum free inflow angle, even if the free inflow angle becomes 69 ° corresponding to the maximum free inflow angle according to the shape of the notch and the opening of the input port,
The flow force acting on the spool can be reduced.

According to the invention described in claim 3,
Since the notch is formed in a direction perpendicular to the axis, the notch can be processed by an end mill, and the workability is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a spool valve according to a first embodiment.

FIG. 2 is a perspective view of a spool.

FIG. 3 is an explanatory diagram of an inflow angle.

FIG. 4 is a longitudinal sectional view of a spool valve according to a second embodiment.

FIG. 5 is a perspective view of a spool.

FIG. 6 is a graph showing a change in pressure loss with respect to a flow rate of a fluid.

FIG. 7 is a graph showing a rise in clutch oil pressure with respect to an elapsed time from the start of energization of the linear solenoid.

FIG. 8 is a longitudinal sectional view of a conventional spool valve.

FIG. 9 is a perspective view of a spool.

FIG. 10 is a view showing a shape of a notch of a conventional spool valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Valve housing 12 Valve hole 13 Input port 14 Output port 17 Spool 18 1st land 19 2nd land 22 1st groove (groove) 26 Linear solenoid (actuator) 28 1st step part 29 2nd step part 34 Notch 35 Curved surface A Line L Axis a Communication part φf Free inflow angle

Claims (3)

[Claims] A valve housing (11) having a valve hole (12), and an input port (1) formed in the valve housing (11) so as to be spaced apart in an axial direction (L) and opening to the valve hole (12).
3) and an output port (14); a spool (17) fitted in the valve hole (12) so as to be slidable in the axial direction (L); and a spool (17) formed to be spaced apart in the axial direction (L). First land (18) and second
A land (19); and a groove formed on the spool (17) and connected to the first land (18) and the second land (19) via the first step (28) and the second step (29), respectively. 22)
And a notch (34) formed so as to cut out the first step portion (28), and an actuator (26) for driving the spool (17) in the direction of the axis (L). By driving the spool (17), the input port (13) communicates with the groove (22), and the fluid flowing from the input port (13) flows through the groove (22) to the output port (1).
In the spool valve discharged from 4), the notch (34) of the spool (17) is connected to the input port (1).
Passing through the communicating part (a) when communicating with 3), the axis (L)
Line (A) that forms free inflow angle (φf) with direction
, Wherein the valve first intersects the bottom of the groove (22). 2. The spool valve according to claim 1, wherein the free inflow angle (φf) is 69 °. 3. The notch (34) is formed in a direction perpendicular to the axis (L).
Or the spool valve according to claim 2.