JPH0776561B2 - Proportional tracking spool valve device - Google Patents

Abstract

A reel speed valve assembly for controlling the speed of a combine reel including a double acting compensator valve (600), a proportional control valve (700), and a relief valve (900), a load sense valve, the reel speed valve may be operated as either a closed or open center valve and may be located at any position in a stack with minimal adjustment to manufacturing procedures. A feedback loop from an assembly outlet port (300) to an assembly inlet port (500) maintains a substantially constant pressure drop across the valve assembly.

Description

TECHNICAL FIELD The present invention relates to the field of servo-following proportional control spool valves.

(Prior Art) Servo-following proportional control valves are well known in this technical field and are described in 1980-1981 edition "Fluid Power Hand Book and Directory", A-141.
Page and 1976, National Conference on Fluid Power (Nation
DWSwaim's "Electronic Proportional Position Control-Application Analysis to Various Water Pressure Control Functions (Electro-pro
portional Position Cotrols-An Analysis for Applic
ation on Various Hydraulic Control Functions) ”.

Conventional proportional control valves have left many problems in terms of quick response to rapidly changing input command signals. Such rapid response in conventional spool valves is adversely affected by the use of dynamic seals. The seal increases the friction because it is in the space between the lumen and the active valve element. Seals of this type are thus known to cause delamination and kinetic friction between the valve element and the lumen. Therefore, the ability to respond quickly is diminished as is the ion frequency traking ability.

Another undesirable feature that reduces the rapid response of conventional proportional control valves is their relatively large drive chamber volume. Large chambers require a relatively large amount of fluid to move, and thus a significant amount of time.
For example, U.S. Patent Nos. 2,526,709, 2,555,755 and
See No. 4,085,920.

Many conventional proportional valves are electrohydraulic with a flapper nozzle and move the spool of the valve. The following patents are representative of this flapper nozzle valve. U.S. Pat.Nos. 3,874,405, 3,598,151, 3,598,
152, 3,742,980, 3,457,956 and 3,749,128. In the devices described in these patents, a DC electrical signal applied to the coils of the pilot stage of a force-balanced torque motor causes the armature-flapper to move either clockwise or counterclockwise between nozzles. Generates torque. This movement limits the outflow of one of the nozzles and facilitates the outflow of the other by imbalanced pressure driving the spool. These flapper nozzle proportional valves
Many problems remained because the valve leaked constantly even when the valve was in the zero state. This zero-state leak is a serious drawback. This is because the valve can be in the zero state for an extended period of time and a significant amount of energy is lost. For example, the loss is 1 / min per valve
4 to 4/10 gallons. The losses in the case of multiple valves are considerable and require cooling elements to eliminate this energy loss. Another problem with flapper nozzle proportional valves is the small orifice that controls the flapper in the valve and the small spring feedback. Small orifices tend to clog,
Small springs are prone to fatigue.

Spool proportional valves also have similar problems because they have small orifices and high leakage at zero conditions. In such valves, zero-state leakage increases undesirably with increasing flow (see US Pat. No. 3,827,453). The following are examples of US patents relating to spools in spool valves. No. 3,027,880, No. 2,748,752, No. 3,53
0,859, 3,163,179, 4,114,650, 3,013,539
Nos. 3,459,224 and 4,046,059.

(Problems to be Solved by the Invention) The present invention aims to solve the problems of the conventional techniques as described above. That is, it is an object of the present invention to provide a proportional follow-up spool valve device in which the main spool responds quickly and accurately to the pilot spool.

(Means for Solving the Problems) According to the present invention, there is provided a proportional follow-up spool valve device which obtains a discharge fluid flow proportional to position control, having the following configuration. A housing having a passage forming an end chamber held at a substantial return pressure;
A main spool having a single internal passage and slidable within the passage of the housing; and a first fluid connection controlled by the main spool and controlling the discharge fluid flow according to the position of the main spool. A pilot spool slidable in the internal passage of the main spool; moving means for moving the pilot spool from a zero position in first and second directions together with the main spool according to the control of the position; First and second drive chambers formed by a main spool and each having a drive area substantially smaller than a cross-sectional area of the main spool, and extending to first and second lands that are constantly engaged with the internal passage. , Fluidly isolated from the respective end chambers by the first and second lands and flowing to the first and second drive chambers, respectively. Respectively connected between the first and second elongated diameter narrowing portions of the pilot spool, and the elongated diameter narrowing portion and the in-end passage of the pilot spool, the elongated diameter narrowing portions being connected to each other. Controlled by the pilot spool and first and second discharge orifices which are fluidly coupled to the end internal passages and determine the response characteristics of the device by their respective values, and (a) the pilot spool is the first Relative to the first drive chamber when moving in the first direction away from the second drive chamber, and (b) the second when the pilot spool moves in the second direction away from the second drive chamber. The fluid is introduced under pressure against the drive chamber of the main spool in the same direction as the pilot spool until the zero position is reached. And a second fluid connections for moving the pool.

(Operation) The first fluid connecting portion controls the discharge fluid flow according to the position of the main spool. The second fluid connection moves under pressure against the first drive chamber when the pilot spool moves in a first direction away from the first drive chamber and in a second direction opposite thereto. In doing so, the fluid is introduced under pressure against the second drive chamber and the main spool is moved in the same direction as the pilot spool until it reaches the zero position.
The first discharge orifice directs fluid from the first drive chamber to a return flow path independent of the first fluid connection when the main spool moves in the second direction. The second discharge orifice directs fluid from the second drive chamber to a return flow path independent of the first fluid connection when the main spool moves in the first direction.

Embodiments Embodiments according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing a spool valve 10 for servo follow-up proportional control. The spool valve 10 comprises a housing 15 having a cylindrical bore 15a for slidably housing the main spool 12. This lumen 15a of the present embodiment corresponds to the passage forming the end chamber in the present invention. The main spool 12 has an opening lumen 12a for slidably accommodating the pilot spool 11. The opening lumen 12a of the present embodiment corresponds to the internal passage of the present invention. The spool valve 10 is connected to the pump 17 for delivering pressurized fluid from the sump 16a through the suction line 17a to the inlet 32 of the spool valve 10.

The fluid operated actuator operated by the spool valve 10 is a piston 22a which operates in a cylinder 22. One end of the cylinder 22 passes through the line 24 and the outflow passage of the spool valve 10.
Connected to 27. Similarly, the other end of the cylinder 22 is a separate line
It is connected to another outlet 29 through 25. A load (not shown) is connected to the shaft of piston 22a in the usual way. Further, the spool valve 10 has a return flow path 40 connected through a return line 18 back to the sump 16a.

The main spool 12 has cylindrical lands 60, 61, 67 and 68 axially spaced about a longitudinal axis. Chamfered grooves (or passages) 64, 48a for measuring the main flow rate are formed on both left and right sides of the land 60. Similarly, chamfered grooves 48b, 65 that measure the main flow rate are formed on both left and right sides of the land 61. Grooves 48a, 48b extend downward into spool 12 and are defined by a cylindrical pressure groove (or recess) 43. A lateral metering orifice 42 extends in the main spool 12 between the groove 43 and the lumen 12a. A cylindrical tank groove (or well) 70 has a discharge orifice 70a formed between the groove 70 and the lumen 12a and is formed between the main flow metering groove 64 and the land 67. Similarly, the cylindrical tank groove 71 has a discharge orifice 71a defined between the groove 71 and the lumen 12a, and is formed on the spool 12 between the groove 65 and the land 68. The land 67 extends to a cylindrical portion 72 having a reduced diameter, and the cylindrical portion 72 defines the left end of the main spool 12. On the other hand, the land 68 is a cylindrical portion 73 with a reduced diameter.
And its cylindrical portion 73 defines the right end of the main spool 12. The connection flow paths 46 and 47 are formed in a direction perpendicular to the axis 16 and form a connection flow path between the inner cavity 12a and the chamber formed by the outer surface of the main spool 12 in these flow paths 46 and 47. is doing.

The lands 60, 61, 67 and 68 on the main spool 12 are slidably and hermetically housed in the cylindrical bore 15a. This inner cavity 15a provides the surface of a cylindrical land 31 provided between an annular recess 30 communicating with the outflow passage 27 and an annular pressure recess 44 communicating with the pressure inflow passage 32. Similarly, the cylindrical land 3 of the lumen 15a
The surface of 3 is provided between an annular recess 35 leading to the outflow passage 29 and a pressure recess (or cavity) 44. At the position of the spool 12 shown in FIG. 1, the depressions 43, 44 form an annular pressure chamber 45. In addition, lumen 15a provides the surface of cylindrical lands 36 and 37. The land 36 is provided between the recess 30 and the annular return recess 40a, and the land 37 is provided between the recess 35 and the return recess 40b. The return depressions 40a, 40b communicate with the return passage 40 and form an annular return chamber having depressions 70, 71 respectively in the neutral position of the spool 12. Incidentally, the depressions 40a, 40b, 44 and 45 of the present embodiment, and the grooves 43, 48a, 48b, 64.
And 65 correspond to the first fluid connection portion of the present invention.

The lumen 15a forms at its left end an extended left end recess 74 for receiving the land 67 and the floating annular spacer 50 which contacts the end wall of the end cap 78. The spacer 50 is
Inside it, there is a cylindrically shaped lumen surface 50d that receives the outer surface of portion 72. Slots are formed in the outer surface of the spacer 50 to provide an O-ring 50a for sealing the fit between the spacer 50 and the recess 74.
Such an arrangement is effective because the spacer 50 "floats" within the depression 74. Further, an annular slot 50b leading to the return passage 19 is undercut at the left end of the spacer 50, and this slot passes through the flow passage 50c and the end chamber 55.
Connected to. The end chamber 55 is formed by the inner cavity 50d of the spacer 50 and the wall 78b of the end cap 78.
In this way, the end chamber 55 is associated with the tank. Wall 78
b is formed by a left end cap 78 that is threadably engaged with the housing 15 to seal the lumen 15a with an O-ring 78a. The left end drive chamber 20 is the right wall 20a of the spacer 50,
It is formed by the left wall 20b of the land 67 and the upper surface of the portion 72. The purpose and operation of the drive chamber 20 will be described in detail later.
The portion 72 of this embodiment corresponds to the diameter narrowing portion of the main spool of the present invention.

It is understood that the members shown within and adjacent to the right end depression 75 of lumen 15a are similar to those described for left end depression 74 and need not be described in further detail. These members are the floating spacer 51, the O-ring 51a, the annular slot 51b, the flow path 51c, the right wall 80b, the return path 19a, and the end chamber 56.
And the right end drive chamber 21.

The pilot spool 11 described above has a lumen 12a of the spool 12.
Housed inside. Spool 11 has 1 in the center
It has a V-groove piston 14 defined by a pair of metering lands 14a, 14b. The V groove 14c is formed between the respective weighing lands 14a and 14b. As shown in FIGS. 1 and 3, at the null position of the pilot spool 11 with respect to the main spool 12, the V groove 14c communicates with the metering orifice 42. Each of the metering lands 14a, 14b form a sharp edge that meters with each wall of the orifice 42 and sealingly engages the lumen 12a to prevent fluid flow from the orifice 42 into the left or right side of the lumen 12. The measuring orifice 42 and the measuring land 14 of the present embodiment
The a and 14b and the V groove 14c correspond to the measuring means in the present invention. The spool 11 also has two axially spaced cylindrical lands 11c, 11d formed at the left and right ends of the spool 11 to seal the left and right ends of the open bore 12a at all positions of the spool 11. Mesh with each other. The measuring land 14a and the land 11c are integrally connected to the stem portion 11a which defines an elongated ring in the longitudinal direction. The stem portion 11a extends over approximately 1/2 of the spool 11 and defines a flow passage in the longitudinal direction. Similarly, the stem portion 11b has a metering land 14b and a land 11d by an annulus extending over approximately half the length of the spool 11 to form a flow path.
Are connected to each other. The stem portion 11 of this embodiment is
a and 11b correspond to the first and second elongated diameter narrowed portions in the present invention. The flow path 11a communicates with the flow path 46 and the orifice 70a, while the stem portion 11b has the orifice 71a.
And to the flow path 47. The left end of the spool 11 is an end 11e provided to engage with the stopper 78c of the end cap 78.
Terminated with. Similarly, the right end 11f of the spool 11 is provided so as to engage with the right end cap 80.
The pressure chamber 45, the orifice 42, the stem portions 11a and 11b, the lands 11c and 11d, the flow paths 46 and 47, the drive chambers 20 and 21, and the walls 20a, 20b, 21a and 21b according to the second embodiment of the present invention are the second embodiment of the present invention. It corresponds to the fluid connection part of.

To give the axial movement of the pilot spool 11,
An actuator 23, which is firmly connected to the left end portion of the spool 11 as shown in the drawing, is provided through the center of the left end portion 11e. Actuator 23 extends through chamber 55 and hermetically extends through end cap 78. The actuator 23 of this embodiment corresponds to the moving means of the present invention.

Next, the operation will be described. In the position shown in FIG. 1,
Pilot spool 11 and main spool 12 have internal bore 15a
Within their central position, each spool is in their null position relative to each other. In this position, the main spool 12 and the land 60 are in close engagement with the lands 36 and 31,
Further, the land 61 is in the neutral position of the inner cavity 15a in a state where the land 61 is hermetically engaged with the lands 33 and 37. Therefore, when the main spool 12 is in this neutral position in the inner cavity 15a, it does not flow from the inflow passage 32 to either the outflow passage 27 or 29. Spool 11 and
When both 12 are in the zero position, no liquid flows from the inflow channel 32 to either the drive chamber 20 or 21.

As shown in FIG. 2, when the pilot spool 11 is moved to the right, the metering land 14a does not engage with the left wall of the metering orifice 42, and the liquid from the inflow passage 32 flows through the pressure chamber 45 and the orifice 42. (Flow 45a), and also to the drive chamber 20 through the stem portion 11a and the flow path 46. The pressure in the drive chamber 20 is effective to move the wall 20b of the main spool 12 to the right between the fixed wall 20a and the movable wall 20b to the position shown in FIG. As long as the opening between the land 14a and the left wall of the orifice 42 remains open,
Pressure is applied to the drive chamber 20 and moves the spool 12 to the right until its opening is closed, causing the spools 11, 12 to move to the null position relative to each other. In this position, as shown in FIG. 3, the spool 12 is out of its neutral or central position with respect to each land in the bore 15a. In particular, the lands 61 and 60 do not engage with the lands 33 and 36, respectively. Therefore, the fluid from the inflow passage 32 flows into the cylinder line 25 through the pressure chamber 45, the measuring groove 48b, the recess 35, and the outflow passage 29. Further, the return flow of the liquid from the cylinder line 24 flows through the outflow passage 27, the depression 30, and the measuring groove 64 to the return groove 40a, and finally to the tank.

As shown in FIG. 3, at this zero position between spools 11 and 12, there is a flow through spool valve 10 that is controlled in proportion to the movement of pilot spool 11 from the neutral position shown in FIG. Is understood. That is, the spool valve 10 provides a fluid outflow output proportional to the movement of the actuator 23 or the electrical signal. The electrical signal is effective to move the actuator 23 in a manner to be described later. In the control position shown in FIG. 3 representing the spools 11, 12 in the null position, there is no liquid flow between the spools.
Therefore, as in the conventional method, energy loss due to continuous flow of liquid between the spools is avoided.

Another example of movement of the pilot spool 11 is shown in FIG. The main spool 12 is at the position shown in FIG.
On the other hand, the pilot spool 11 is moved to the left from the position shown in FIG. As a result, the opening is formed between the land 14b and the right wall of the orifice 42. Therefore, the fluid flow 45b reaches the drive chamber 21 from the inflow passage 32, the pressure chamber 45, the orifice 42, the stem portion 11b, and the flow passage 47. In the method described above, the pressure on the wall 21b is
Effective to move the main spool 12 to the left until the 2 reaches the new control position, the null position of the pilot spool 11. In this new control position (not shown), land 60 does not engage land 31 and land 61 does not engage land 37.

Therefore, the liquid from the inflow passage 32 passes through the measuring groove 48a, and the depression 3
Flows through the outlet channel 27 to the cylinder 22. The return flow of fluid flows through line 25, through outflow channel 29, depression 35 and groove 65 to return depression 40b. That is, the spool valve 10 operates as a servo follow-up and proportional control valve.

It will be appreciated that in order to provide a fast and accurate response of the spool valve 10 to movement of the pilot spool 11, the drive chambers 20 and 21 at each end preferably have a minimum fluid volume. Due to the rapid response of the spool valve 10, these drive chambers need only have sufficient volume to overcome the flow effects of the main spool and provide the force necessary to move the main spool 12. One of the actions of these flows is shown in FIG. 3 as the flow from the inflow passage 32 through the pressure chamber 45 and the metering groove 48b to the recess 35 and the outflow passage 29. It is well known by those skilled in the art that these flow effects include the Bernoulli effect and other effects of flow across the main spool 12.

The annular drive chambers 20 and 21 are dimensioned in one direction to provide a lumen 12
It has a minimum capacity by having an outer diameter equal to a and an inner diameter equal to the outer diameter of the depressions 72, 73, respectively. In the other dimension, the drive chambers 20,21 are configured to have a minimum volume by the respective sidewalls of the floating spacers 50,51 and the respective sidewalls of the lands 67,68. Thus, the drive chambers 20, 21 each have a volume that is effectively operating and is substantially smaller than the volume of the spool end chambers 55, 56. More specifically, the drive area of the drive chamber 20 defined by the wall 20b is substantially smaller than the solid or metal transverse cross-sectional area of the main spool 12 itself at its maximum diameter position. The maximum cross-sectional area is obtained at land 67 which is perpendicular to axis 16. The remaining cross-sectional area defined by the ends of section 72 is the return pressure in end chamber 55. Similarly, the wall 21b has an area much smaller than the maximum solid cross-sectional area of the spool 12, and the end of the portion 73 has a return pressure.

Further, as mentioned above, the spacers 50, 51 provide one side wall of the drive chambers 20, 21 respectively, without applying a load to the device. Each spacer floats within lumen 15a,
Further, the ends of the spools 11 and 12 can be operated in the end chambers 55 and 56 at the tank pressure or the discharge pressure. That is,
The ends of each spool 11, 12 do not play any role in movement.

The drive chamber 20 is located near the left end of the spool 12 between the tank groove 40a and the end chamber 55 at the tank pressure or the return pressure. In this way, even small leaks from the drive chamber 20 will flow harmlessly into the tank rather than outflowing and adversely affecting control ports such as the dimples 30. Similarly, the drive chamber 21 has a groove 40b.
And between the end chambers 56. Thus, any leaks
It flows harmlessly into the tank without adversely affecting the depression (control port) 35. That is, the spool valves are spools 11 and 12
So you don't need a dynamic seal. This allows the spool valve 10 to respond quickly to rapidly changing step functions, such as slow movements for accurate positioning.

Further, the stem portions 11a and 11b are connected to the orifice 42 and the drive chamber.
It is sized to provide a minimum volume flow path between 20, 21 and thus minimizes the confined volume compression loss.

In the example shown in FIG. 2, it is assumed that the pilot spool 11 is rapidly moved to the right with a relatively large step movement, and the metering orifice 42 is completely opened. As a result of the relatively large opening in orifice 42, pressure chamber 45 to drive chamber 20
A relatively large scale fluid flow occurs. The resulting abrupt step function of pressure in the drive chamber 20 helps to move the main spool 12 quickly to the right to close its large opening. In this way, the drive chamber 20 undergoes a rapid initial change in pressure effective to rapidly close the orifice 42. This abrupt change in pressure causes passage 42
When is closed, it decreases to a fixed amount. Meanwhile, the second
In the example shown, when spool 11 is moved to the right by a relatively small distance, land 14a and orifice 42
Only a small opening is provided between it and the left wall. This can also be applied to the movement of the spool 11 to the right as in the example of FIG. As a result, the main spool 12 makes a predetermined rightward movement until the opening is closed. In this way, the spool valve 10
It responds largely to a large step function related to the movement of, and responds to a small scale when the step function decreases.

It can be seen that the discharge orifice 70a is provided to discharge the fluid from the drive chamber 20. This drive chamber 20 is compressed when the main spool 12 is moved to the left. Similarly,
The discharge orifice 71a, when the drive chamber 21 is compressed by the movement of the spool 12 to the right as shown in FIG.
The fluid is discharged from the drive chamber 21. Orifice
The sizes of 70a and 71a are factors that determine the response characteristics of the spool valve 10 device. This is because the compression of each of the drive chambers 20 and 21 is determined by the size of its orifice. As with another embodiment of the invention shown in FIG. 6, discharge orifices 70a, 71a (reference numeral 70 in FIG. 6).
b, 71b) to the return path 19, 19a (6th)
(Represented by reference numerals 19 ', 19a' in the figure) may be returned to the tank.

In the embodiment shown in FIG. 6, the pilot spool 11 has the inner end passages X and Y provided inside the first and second end chambers 5 and 5.
It is open to 5, 56. The first and second short passages X,
The discharge orifices 70b and 71b are opened in Y, so that the passages X and Y in the end portion are formed in the discharge orifices 70b and 71b and the end chamber 5.
Guide pilot flow between 5 and 56. By providing the discharge orifices 70b and 71b as in this embodiment, the first
A fluid flows from the end chamber 55 to the return path 19 branched from the return recess 40a, and from the second end chamber 56 to the return path 19a branched from the return recess 40b. The return channels 19, 19a return the fluid from the end chambers 55, 56 to the individual sumps 16a via the return recesses 40a, 40b.

In such a structure, the return recesses 40a, 40b and the drain sump
If the flow to and from 16a is restricted, an increase in main flow pressure can occur. Such a pressure change in the return line 18 causes the return line 18 to flow fluid to the spool valve.
It can also occur when sending to the discharge sump 16a from sources other than 10. However, the return line 18 can connect separate return lines 19 ', 19a' to the drain at atmospheric pressure, as in the embodiment of FIG. There is no increase in pressure at 19a '. The embodiment of FIG. 6 uses independent return paths 19 ', 19a' to make the pilot flow unaffected by pressure changes in the return line 18. Therefore, even if the pressure of the main flow changes, it is possible to prevent interference between the pilot flow and the main flow. As a result, the position of the pilot spool 11, and hence the position of the main spool 12, is accurately controlled, the valve is stabilized, and the response characteristic is improved.

Thus, by providing independent return paths 19 ', 19a' from the discharge orifices 70b, 71b, the return depressions 40a, 40a
It will be appreciated that interference between the mainstream for b and the pilot pressure in the drive chambers 20, 21 is avoided. This is especially useful if the pressure builds up in the return recesses 40a, 40b due to the fluid resistance between the valve and the tank sump 16a. Moreover, this is even more effective if the pressure changes in the return line 18 to the tank. The pressure in the return line to the tank may vary, for example if the return line to the tank carries fluid from another valve.

The pilot spool 11 is moved by the very light force exerted on the actuator 23, so that it is in pressure equilibrium. Due to the pressure balance, a bias due to a spring is not applied to the pilot spool 11 and the end chambers 55 and 56 which the pilot spool reciprocates, and the pilot spool 11 is balanced in the tank or the drain. Such light force on the actuator 23 is provided by a digital drive motor such as the Bidirectional Linear Actuator Series 9200 from Airpax, Inc. (Cheshire 06410, CT). Such a linear actuator provides a linear motion of one-half thousandth each time a digital pulse is applied. By inputting digital pulses to the linear actuator in this way, the pilot spool 11 is moved and the main spool
Followed exactly by 12. Thus, the spool valve
Reference numeral 10 gives the flow from the pressure inflow passage 32 to the outflow passages 27, 29 exactly and repeatedly. In another embodiment, the actuator 23
Is manually moved or by a proportional or on / off type linear solenoid connected to each end of spool 11.

As described above, according to the present invention, the first fluid connecting portion controls the discharge fluid flow in accordance with the position of the main spool,
The second fluid connection moves under pressure against the first drive chamber when the pilot spool moves in a first direction away from the first drive chamber and in a second direction opposite thereto. At this time, fluid is introduced under pressure to the second drive chamber and the main spool is moved in the same direction as the pilot spool until it reaches the zero position, so there is little energy loss and a proportional response spool valve with fast response speed. The device can be obtained. Moreover, when the first discharge orifice moves the main spool in the second direction, the fluid is caused to flow from the first drive chamber to the return flow path independent of the first fluid connection portion, and the second discharge orifice is discharged. When the orifice moves the main spool in the first direction, it causes the fluid to flow from the second drive chamber to the return flow path independent of the first fluid connection portion, and therefore changes with the pressure of the main flow. However, it is possible to prevent interference between the pilot flow and the main flow. As a result, the position of the pilot spool, and thus the position of the main spool, is precisely controlled, the valve is stabilized, and the response characteristic is improved.

[Brief description of drawings]

1 to 4 are front cross-sectional views of a proportional follower spool valve device according to the present invention, FIG. 5 is a perspective view of the components of FIGS. 1 to 4 being exploded, and FIG. 6 is another embodiment of the present invention. FIG. 7 is a simplified partial sectional view according to an embodiment. 10 …… Spool valve, 11 …… Pilot spool, 11a, 11b …… Stem part, 11d, 31, 33, 36, 37, 60, 61, 66, 67, 68 …… Land, 12 …… Main spool, 14a , 14b …… Weighing land, 14c …… V-groove 15 …… Housing, 19, 19 ′, 19a, 19a ′ …… Return path, 20, 21, 67, 68 …… Drive room, 23 …… Actuator, 27, 29 ... Outflow channel, 30, 35, 43, 70, 71, 72, 73, 74 ... Recess, 32 ... Inflow channel 40 ... Return channel, 40a, 40b ... Return recess, 42 ... Metering orifice , 46, 47, 51c ... Flow path, 55, 56 ... End chamber, 70a, 70b, 71a, 71b ... Discharge orifice, X, Y ... End passage.

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 999999999 Thomas E. Sauner USA, Pennsylvania 18966, Holland, Wood Lake Drive 230 (72) Inventor Kenneth Davryu Saunel USA, Pennsylvania 18938, New Hope, Lethodox Drivie 43 72) Inventor, Stephen Käuzell, USA 18966, Pennsylvania 18966, Holland, Larch Circle 39 (72) Inventor, Thomas E. Saunel, USA, Pennsylvania 18966, Holland, Utdrake Drive 230 (56) Bibliography 58-20702 (JP) , U) Actual Development Sho 50-111600 (JP, U) Japanese Patent Sho 36-21424 (JP, B1)

Claims (6)

[Claims] 1. A proportional follower spool valve device for obtaining a discharge fluid flow proportional to position control, comprising a housing having a passage forming an end chamber held at a substantial return pressure, and a single internal passage. A main spool that is slidable in the passage of the housing; a first fluid connection portion that is controlled by the main spool and that controls the discharge fluid flow according to the position of the main spool; A pilot sprue capable of sliding in an internal passage; a moving means for moving the pilot spool in the first and second directions from a zero position together with the main spool according to the control of the position; First and second drive chambers each having a drive area substantially smaller than the cross-sectional area of the main spool, and the internal passage To the first and second lands that are constantly engaged with, and are fluidly isolated from the respective end chambers by the first and second lands, and fluid to the first and second drive chambers, respectively. Respectively connected between the first and second elongated diameter narrowing portions of the pilot spool, and the elongated diameter narrowing portion and the in-end passage of the pilot spool, the elongated diameter narrowing portions being connected to each other. First and second discharge orifices, each of which is fluidly coupled to the end internal passage and determines the response characteristic of the device according to each value, and is controlled by the pilot spool, (a)
Relative to the first drive chamber when the pilot spool moves in a first direction away from the first drive chamber, and (b) in a second direction away from the second drive chamber. And a second fluid connecting portion for moving the main spool in the same direction as the pilot spool until the zero position is reached by introducing the fluid under pressure to the second drive chamber when moving. A proportional follow-up spool valve device characterized in that 2. The proportional follower according to claim 1, wherein the first and second drive chambers are formed on the main spool adjacent to an end portion of the main spool. Spool valve device. 3. The first and second drive chambers are respectively formed in the diametrically narrowed portion of the main spool, and have a volume substantially smaller than that of each of the end chambers. The proportional tracking spool valve device according to the second aspect of the present invention. 4. A floating type first device which is disposed in each of the end chambers and slidably receives the diameter narrowing portion and constitutes one fixed wall of each of the first and second drive chambers. The proportional tracking spool valve device according to claim 3, further comprising: a second spacer. 5. The first in the pilot spool
And (a) a first section when the pilot spool moves in the first direction, and (b) the pilot spool is fluidly connected to the second elongated diameter narrowing section. A proportional follow-up spool valve device according to claim 1, characterized in that it is provided with metering means for receiving fluid under pressure against the second section when moving in the direction. 6. A proportional tracking spool valve device according to claim 5, wherein said measuring means includes a V-shaped groove having a pair of lands.