JP5454028B2 - Directional control valve device - Google Patents

Description

  The present invention relates to a directional control valve device for a hydraulic circuit used for controlling a hydraulic operation system.

  As a control mechanism element of various hydraulically operated machines, a directional control valve that switches a conduction relationship between hydraulic circuits is frequently used.

  The most common form of this direction control valve is a so-called spool valve. In this spool valve, a rod having an outer diameter step portion is inserted into a cylindrical hole, and the axial position of the rod is slid to change, whereby a plurality of hydraulic circuit conduction holes and rod outer diameter step portions are provided. Is switched to switch the conduction relationship between the hydraulic circuits.

  This spool valve type directional control valve is frequently used because of its excellent characteristics that can be controlled with a very small operating force. However, since the spool valve type directional control valve requires a gap that allows sliding movement between the cylindrical hole and the rod due to its structural principle, the hydraulic oil leaks through the gap. However, there is a weak point that complete disconnection between hydraulic circuits is impossible. For this reason, the use of the directional control valve of the spool valve type is limited to a large flow rate circulation type hydraulic system using a power-driven hydraulic pump, in which some leakage loss is not a real harm. For example, in applications where a complete shutoff function is required, such as a system that uses accumulator hydraulic pressure as a hydraulic source, and a slight shutoff between hydraulic circuits is required, the continuity between each hydraulic circuit is opened and closed by a poppet valve. A poppet valve type directional control valve having a structure as described above is used. This type of poppet valve type directional control valve is also disclosed in Patent Documents 1 and 2, for example.

JP-A-10-325476 JP-A-10-332006

  The above poppet valve type directional control valve is excellent in that the conduction state between the hydraulic passages can be completely shut off without leakage, but the principle that realizes the completely shut off function is the poppet. It depends on the close contact between the valve and the valve seat. For this reason, in order to ensure that the poppet valve and the valve seat are in close contact with each other in consideration of variations in the processing dimensions of the component parts, a valve spring that presses the poppet valve against the valve seat is provided and the deflection of the valve spring is reduced. A structure in which the poppet valve is securely pressed against the valve seat by force is the most common. As another method for applying a pressure contact force to the poppet valve, there is an example using hydraulic thrust or electromagnetic force.

  In any case, in the case of this directional control valve of the poppet valve type, it is necessary to apply a pressure contact force to the poppet valve by some method, and in order to open the poppet valve in the closed state by the pressure contact force, The poppet valve must be given a valve opening direction operating force that is greater than the pressure contact force.

  For this reason, the poppet valve type directional control valve can realize a complete shut-off function without leakage, but has a problem that it requires a corresponding control operation force for opening / closing control of the poppet valve.

  Incidentally, the direction control valve of the poppet valve type, as its structural principle, shuts off the conduction between the hydraulic circuits by closing the conduction hole between the hydraulic circuits by the pressure contact of the poppet valve when the valve is closed. If there is a pressure difference between the shut off hydraulic circuits, the differential pressure thrust, which is the pressure difference multiplied by the shut off area, acts on the poppet valve. I'm jealous. To solve this differential pressure thrust problem, the differential pressure thrust is added to the poppet valve by adding a piston structure that simultaneously generates a differential pressure thrust in the opposite direction with the same value as the differential pressure thrust due to the shut-off area when the valve is closed. There is also used a method for canceling and canceling, and there are various structural forms.

  However, even if the influence of the differential pressure thrust is eliminated by such a method, the pressure contact force to guarantee a reliable shut-off function when the valve is closed is not unnecessary. The problem of requiring operating force could not be solved.

  Therefore, an object of the present invention is to solve the problem that the control operation force is large, which is the fate of a poppet valve type directional control valve used in a hydraulic operation system that particularly dislikes leakage loss between hydraulic circuits, and is extremely slight. An object of the present invention is to provide an ideal directional control valve device that can be controlled by a control operation force and does not have a leakage loss when the valve is closed.

In order to achieve the above object, the present invention switches the conduction relationship between three or more hydraulic circuits by opening / closing control of a plurality of poppet valve elements, and uses a cam mechanism to open and close the plurality of poppet valve elements. A direction control valve device for imparting motion, wherein each of the plurality of poppet valve elements is provided in a housing member, and is movable in the axial direction in the housing member. A driven member that is mounted so as to be movable in the axial direction of the poppet valve member, and that moves in the axial direction of the poppet valve member in response to pressing by the cam mechanism serving as a control input member, and the poppet valve member and the driven member A spring element that is interposed between the poppet valve member and the driven member and changes in deflection amount according to a relative displacement between the poppet valve member and the driven member. A cam member that drives both of the two poppet valve elements of the valve element, and the cam member moves when the amount of deflection of the spring element of one of the two poppet valve elements increases; like the amount of deflection of the spring element of the poppet valve element is reduced, have a cam nose for driving the two poppet valve element, said spring element, the spring constant has a substantially constant linear characteristic, When the relative displacement between the poppet valve member and the driven member is zero, the bending amount is almost zero, and when the relative displacement between the poppet valve member and the driven member is the maximum displacement, the bending amount is It is interposed between the poppet valve member and the driven member so as to be in a maximum deflection state .

  According to the present invention, the problem of large control operation force, which is the fate of a poppet valve type directional control valve used in a hydraulic operation system that particularly dislikes leakage loss between hydraulic circuits, is solved, and extremely few control operations are performed. It is possible to provide an ideal directional control valve device that can be controlled by force and has no leakage loss when the valve is closed.

FIG. 1 is a cross-sectional view of a directional control valve device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the operation of the directional control valve device according to the embodiment of FIG. 1. FIG. 3 is a diagram illustrating the operation of the directional control valve device according to the embodiment of FIG. 1. FIG. 4 is a diagram illustrating the operation of the directional control valve device according to the embodiment of FIG. 1. FIG. 5 is a diagram showing a response characteristic (valve closing → valve opening) of the driven member. FIG. 6 is a diagram showing a change characteristic of the cam contact angle (valve closing → valve opening). FIG. 7 is a diagram showing a change characteristic (valve closing → valve opening) of the spring reaction force and the cam moving load. FIG. 8 is a diagram illustrating a response characteristic (valve opening → valve closing) of the driven member. FIG. 9 is a diagram showing a change characteristic of the cam contact angle (valve opening → valve closing). FIG. 10 is a diagram showing a change characteristic (valve opening → valve closing) of the spring reaction force and the cam moving load. FIG. 11 is a diagram showing cam movement load characteristics at the time of synchronous cancellation. FIG. 12 is a diagram showing driven member displacement characteristics. FIG. 13 is a diagram showing valve opening lift amount characteristics. FIG. 14 is a diagram showing a valve spring deflection characteristic. FIG. 15 is a diagram showing cam contact angle change characteristics. FIG. 16 is a diagram illustrating a cam movement direction component force characteristic. FIG. 17 is a cross-sectional view of a directional control valve device according to another embodiment. FIG. 18 is a view showing the operation of the directional control valve device according to the embodiment of FIG. FIG. 19 is a diagram illustrating the operation of the directional control valve device according to the embodiment of FIG. FIG. 20 is a diagram illustrating the operation of the directional control valve device according to the embodiment of FIG. FIG. 21 is a view showing the operation of the directional control valve device according to the embodiment of FIG.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the directional control valve device 1 according to the present embodiment has a plurality of (two in the illustrated example) poppet valve elements in a conduction relationship between three or more hydraulic circuits (three in the illustrated example). 3 is switched by the opening / closing control 3, and the opening / closing motion is given to the plurality of poppet valve elements 3 by using the positive cam mechanism 4.

  A directional control valve device 1 according to this embodiment includes a housing member 5 to which three hydraulic circuits A, B, and C are connected. Two hollow holes 6 are formed in the housing member 5 in parallel with each other, and each hollow hole 6 is formed by a poppet valve member 7 which will be described later, with a first chamber 8 and a second chamber on both ends in the axial direction of the poppet valve member 7. It is divided into a chamber 9 and an intermediate third chamber 10. The side wall of the housing member 5 has a first port 11 communicating with the third chamber 10 on the right side from the outside, a second port 12 communicating with the first chamber 8 on the right side from the outside, and a left port from the outside. A third port 13 communicating with the first chamber 8 is formed. In addition, a communication port 14 that connects the right third chamber 10 and the left third chamber 10 is formed in the intermediate wall portion of the housing member 5.

  In the present embodiment, the hydraulic circuit A is connected to the first port 11 of the housing member 5, the hydraulic circuit B is connected to the second port 12, and the hydraulic circuit C is connected to the third port 13.

  In the present embodiment, each of the poppet valve elements 3 is provided in the housing member 5, and the poppet valve member 7 is movable in the axial direction in the housing member 5, and the poppet valve member 7 is in the axial direction of the poppet valve member 7. And a driven member 15 that moves in the axial direction of the poppet valve member 7 in response to pressing by the cam member 24 of the cam mechanism 4 serving as a control input member, and between the poppet valve member 7 and the driven member 15. And a spring element 16 whose deflection amount changes according to the relative displacement between the poppet valve member 7 and the driven member 15.

  In this embodiment, the poppet valve members 7 of the two poppet valve elements 3 are disposed on the housing member 5 so as to be movable in parallel to each other (vertical direction in FIG. 1). The poppet valve member 7 of the present embodiment is mainly composed of a first rod portion 17, a first flange portion 18, a second flange portion 19, and a second rod portion 20, and the first rod portion 17 is a housing. The first flange portion 18 divides the first chamber 8 and the third chamber 10, and the second flange portion 19 is slidably supported by the housing member 5. The second chamber 20 is partitioned from the third chamber 10 and supported by the housing member 5 so as to be slidable. Further, the poppet valve member 7 is formed with a communication hole 21 for communicating the first chamber 8 and the second chamber 9.

  In the present embodiment, a spring element mounting space (concave portion) 22 is formed in the second rod portion 20 of the poppet valve member 7, and the driven member 15 extends in the axial direction of the poppet valve member 7 in the spring element mounting space 22. It is slidably mounted.

  The spring element 16 of the present embodiment is a valve spring such as a coil spring. The spring element 16 of this embodiment has a substantially constant spring constant. In the present embodiment, the spring element (valve spring) 16 is disposed between the spring element mounting space 22 of the poppet valve member 7 and the flange 23 of the driven member 15. In the present embodiment, the spring element 16 has substantially zero deflection when the relative displacement between the poppet valve member 7 and the driven member 15 is zero (the state of the right spring element 16 in FIG. 1). When the relative displacement between the poppet valve member 7 and the driven member 15 is the maximum displacement (the state of the left spring element 16 in FIG. 1), the amount of bending is set to the maximum. .

  The cam mechanism 4 of this embodiment is a positive acting type that does not depend on the valve spring force. The cam mechanism 4 of the present embodiment includes a cam member 24 that drives the two poppet valve elements 3 together. That is, in this embodiment, a structure is adopted in which three poppet valve elements having the same configuration are driven together by one cam member 24. In the present embodiment, the cam member 24 is movable in a direction perpendicular to the axial direction of the poppet valve member 7 (the left-right direction in FIG. 1). The cam member 24 is configured such that when the amount of bending of the spring element 16 of one of the two poppet valve elements 3 increases, the amount of bending of the spring element 16 of the other poppet valve element 3 decreases. , With cam ridges 25, 26 for driving the two poppet valve elements 3.

  In the present embodiment, the positive cam mechanism 4 is configured by integrally forming the upper and lower cam ridges 25 and 26 on one cam member 24 so as to sandwich the both axial ends of the poppet valve member 7. doing. Balls 27 and 28 are interposed between the cam member 24 and the poppet valve member 7 and between the cam member 24 and the driven member 15.

  In the present embodiment, the cam profile of the cam crest 26 on the lower side of the cam member 24 is changed from the valve fully open position (position of the poppet valve member 7 on the right side in FIG. 1) to the valve closing seating position (right poppet in FIG. 2). The cam profile gives the driven member 15 a displacement amount that exceeds the displacement amount of the poppet valve member 7 up to the position of the valve member 7. By doing so, the relative displacement between the poppet valve member 7 and the driven member 15 is zero until the poppet valve member 7 reaches the valve closing seat position from the valve fully open position, and the poppet valve member 7 tries to move beyond the valve closing seat position. The driven member 15 deflects the spring element 16 interposed between the poppet valve member 7 and the driven member 15 that cannot move beyond the valve-closing seating position, and the spring element 16 bends after the valve-closing seating position increases. The reaction force is configured to utilize the poppet valve member 7 as a valve closing pressure contact force that presses the valve seat S provided on the housing member 5.

  Further, the cam profile of the cam crest 26 on the lower side of the cam member 24 is a sine curve that is preferable in terms of acceleration change characteristics that make the movement behavior of the poppet valve member 7 smooth when the poppet valve member 7 is opened and closed. The cam profile is given to the follower member 15 with the change characteristic of the shape.

  With this setting, the deflection displacement amount of the spring element 16 in the region where the driven member 15 is pushed by the cam crest 26 on the lower side of the cam member 24 after the seating of the poppet valve member 7 is as follows. Since the change characteristic according to the displacement of the driven member 15 moving in a sine curve shape with respect to the displacement amount, the bending reaction force of the spring element 16 follows the sine curve change characteristic.

  The bending reaction force of the spring element 16 acts on both the poppet valve member 7 and the driven member 15, and the angle of the bending reaction force of the spring element 16 according to the cam contact angle between the driven member 15 and the cam member 24. The force acts in the moving direction of the cam member 24. The cam contact angle between the driven member 15 and the cam member 24 is determined by the displacement of the poppet valve member 7 and the driven member 15 by the cam profile having a sine curve shape. It will change along with.

  Here, the spring constant of the valve spring 16 interposed between the poppet valve member 7 and the driven member 15 is set to Ks, and the maximum deflection amount of the valve spring from the valve closing seating position of the poppet valve member 7 is set as a reference. With respect to the displacement L when the cam member 24 is moved in the valve opening direction from the valve spring maximum deflection position as Lt, where δmax is the amount of movement of the cam member 24 while giving the maximum amount of valve spring deflection. The change characteristic of the displacement amount δ of the valve spring pushing by the cam member 24 is set as follows:

δ = δmax * cos (L * π / 2 / Lt)
The change characteristic of the cam contact angle θ between the cam member 24 and the driven member 15 with respect to the displacement L of the cam member 24 is an L derivative of the displacement δ, and is expressed by the following equation.

θ = tan ⁻¹ (−δmax * sin (L * π / 2 / Lt) * π / 2 / Lt)
The thrust Fc that the valve spring deflection reaction force Fs acts in the moving direction of the cam member 24 is expressed by the following equation.

Fc = Fs * tan (θ) = − Fs * δmax * sin (L * π / 2 / Lt) * π / 2 / Lt
The valve spring deflection force Fs can be expressed by the following equation.

Fs = δ * Ks = δmax * cos (L * π / 2 / Lt) * Ks
Therefore, the moving thrust Fc of the cam member 24 is expressed by the following equation.

Fc = −Fs * δmax * sin (L * π / 2 / Lt) * π / 2 / Lt
= −δmax * cos (L * π / 2 / Lt) * Ks * δmax * sin (L * π / 2 / Lt) * π / 2 / Lt
= −δmax ^ 2 * sin (L * π / 2 / Lt) * cos (L * π / 2 / Lt) * π / 2 / Lt * Ks
For example, when the valve spring maximum deflection amount δmax is 2 mm, the displacement amount Lt of the cam member 24 is 3 mm, and the spring constant Ks of the valve spring 16 is 8 kg / mm, a maximum valve closing pressure contact force of 16 kg is obtained. The response characteristic of the driven member 15 (valve closing → opening) with respect to the displacement of the cam member 24 is as shown in FIG. 5, and the change characteristic of the cam contact angle between the cam member 24 and the driven member 15 (valve closing → opening). FIG. 7 shows the spring reaction force and the change characteristic of the cam movement load (valve closing → valve opening) as shown in FIG.

  Further, the response characteristic of the driven member 15 with respect to the displacement of the cam member 24 (open valve → closed valve) is as shown in FIG. 8, and the change characteristic of the cam contact angle between the cam member 24 and the driven member 15 (open valve → closed valve). The valve is as shown in FIG. 9, and the spring reaction force and the change characteristic of the cam movement load (valve opening → valve closing) are as shown in FIG.

  That is, when the cam member 24 is moved from the valve spring maximum deflection position to the valve spring deflection zero position, thrust in a direction that promotes the movement of the cam member 24 acts on the cam member 24. It acts on the cam member 24 as a resistance thrust. If the two poppet valve elements 3 having the same operation timing are driven together, the angular component forces of the bending reaction forces of the two spring elements 16 cancel each other, and the load of the moving operation of the cam member 24 is reduced. Can be made substantially zero (see FIG. 11).

  Next, the operation of the directional control valve device 1 according to this embodiment will be described with reference to FIGS.

  In this embodiment, as shown in FIG. 1, when the cam member 24 is in the rightmost reference position, the cam profile of the cam crest 26 with respect to the left poppet valve element 3 of the two poppet valve elements 3 is closed. Since the valve spring is at the maximum deflection position in the valve region, the left poppet valve element 3 is closed by the pressure contact force caused by the maximum deflection reaction force of the spring element 16, and the cam crest 26 of the right poppet valve element 3 The cam profile is in the fully open position and the right poppet valve element 3 is open.

  Therefore, in the state shown in FIG. 1, the hydraulic circuit A and the hydraulic circuit B are in a conductive state through the right first chamber 8 and the right third chamber 10, and the hydraulic circuit C is in a cut-off state.

  When the cam member 24 is moved to the left (in the direction of arrow D) from the state shown in FIG. 1, first, as shown in FIG. 2, the poppet valve member 7 of the right poppet valve element 3 is moved to the cam member 24. It is pushed up by the cam crest 26 and reaches the valve-closing seating position. In the state shown in FIG. 2, since the spring element 16 of the right poppet valve element 3 has not been bent, the force affecting the movement of the cam member 24 from the state shown in FIG. 1 to the state shown in FIG. Only resistance.

  When the cam member 24 is further moved leftward from the state shown in FIG. 2, the spring element 16 of the right poppet valve element 3 starts to bend as shown in FIG. The angular component force starts to increase, but in synchronism with this, the cam contact angle between the driven member 15 of the left poppet valve element 3 and the cam member 24 is inclined from the horizontal state, and the cam member 24 moves in the moving direction. Since the negative angular component force starts to increase, the angular component forces of the bending reaction forces of these two spring elements 16 cancel each other. Therefore, the force that affects the movement of the cam member 24 is only the frictional resistance force, and the state shown in FIG. 2 is changed to the state shown in FIG.

  In the state shown in FIG. 3, both the poppet valve elements 3 are in the closed valve seating position. However, the bent state of the spring element 16 is that the right poppet valve element 3 is in the maximum bent state and the left poppet valve element 3 is Since the state has reached zero, even in the region where the cam member 24 is further moved to the left from the state shown in FIG. 3, the right poppet valve element 3 in which the cam contact angle is horizontal and the cam contact angle are Since both of the left poppet valve elements 3 which are changing processes but have no bending reaction force, the angular component force of the bending reaction force of the spring element 16 does not act. The cam member 24 can be moved from the state shown to the state shown in FIG.

  The state shown in FIG. 4 is the reverse of the state shown in FIG. 1, and the hydraulic circuit A and the hydraulic circuit C are in a conductive state through the left first chamber 8, the communication port 14, and the right third chamber 10. The hydraulic circuit B is cut off, and the switching valve function of the three hydraulic circuits is achieved.

  FIG. 12 shows the response characteristics of the driven member 15 with respect to the displacement of the cam member 24 in the above operation, FIG. 13 shows the valve opening lift amount change characteristics of the poppet valve member 7, and FIG. 14 shows the valve spring deflection amount change characteristics. FIG. 15 shows the cam contact angle change characteristic between the cam member 24 and the driven member 15, and the valve spring deflection reaction force change characteristic and thereby the valve spring deflection reaction force angle acting as the moving direction force of the cam member 24. The change characteristics of the component force are shown in FIG.

  Thus, according to the present embodiment, the angular component of the bending reaction force acting on the cam member 24 by the spring elements 16 of the two poppet valve elements 3 is mutually offset, and the load of the movement operation of the cam member 24 is reduced. Since it can be reduced, it is possible to realize an ideal directional control valve device 1 that can be controlled with very little control operation force and does not have a leakage loss when the valve is closed.

  Next, a directional control valve device 2 according to another embodiment will be described.

  The same components as those in FIG. 1 are denoted by the same reference numerals, description thereof will be omitted, and only differences will be described.

  As shown in FIG. 17, in this embodiment, a spring element mounting space (concave portion) 29 is also formed in the first rod portion 17 of the poppet valve member 7, and another driven member is provided in this spring element mounting space 29. 30 is slidably mounted in the axial direction of the poppet valve member 7. Further, between the poppet valve member 7 and the driven member 30, another spring element 31 whose amount of deflection changes according to the relative displacement between the poppet valve member 7 and the driven member 30 is interposed.

  Here, in the principle of the present invention, the cam member 24 is moved from the valve-opened state to the valve-closed direction as a condition that the angular component forces of the bending reaction forces generated by the spring elements 16 of the two poppet valve elements 3 cancel each other. When the valve spring deflection amount increasing characteristic that increases in a sine curve from the valve-closed seating position when it is moved is a cam profile characteristic in which the deflection amount does not change after reaching the maximum deflection position, the driven member 15 And the poppet valve member 7 are required to have zero set force and a constant linear characteristic of the spring constant of the spring element 16.

  However, assuming a general coil spring as a form of the valve spring 16 that is easy to be mounted on such a part, the coil spring manufacturing characteristics include a free state near zero deflection and a maximum deflection state near the coil wire. The load deflection characteristic is likely to vary due to the influence of the shape accuracy of the end winding part, and it is difficult to guarantee a stable characteristic. For this reason, it is usually recommended to use a coil spring within a range of 20 to 80% of the maximum amount of deflection when obtaining a stable load deflection characteristic.

  In other words, in consideration of such characteristic restrictions of the coil spring, when it is attached with an initial deflection of 20% or more of the maximum deflection amount, its set force cannot be zero, and the spring elements of the two poppet valve elements 3 The angular force canceling relationship of the bending reaction force generated by 16 is broken.

  As a countermeasure, two spring elements 16 and 31 to be mounted between the driven member 15 and the poppet valve member 7 are connected in series, and the spring element mounting spaces 22 and 29 provided in one member have a 20% or more in the space. An effective method is to apply the initial deflection and attach the other member to the contact boundary between the two spring elements 16 and 31 in series (see FIG. 17).

  With such a structure, the set force of the two spring elements 16 and 31 acts on the member sandwiched between the two spring elements 16 and 31 in the canceling direction to balance each other. It is possible to obtain characteristics equivalent to a force zero valve spring.

  Incidentally, since the spring constant characteristic in this case acts as the sum of the spring constant values of the two spring elements 16 and 31, the two spring elements 16 that exhibit the necessary spring constant value are used. 31 each spring constant value is half as low, and the sensitivity of the influence of the change in the spring deflection reaction force on the variation in manufacturing dimensions is low, so this aspect is also advantageous for characteristic stabilization.

  The operation of the directional control valve device 2 according to this embodiment is shown in FIGS.

  Also in this embodiment, by moving the cam member 24 to the left from the state shown in FIG. 17 to the state shown in FIG. 21, the hydraulic circuit A and the hydraulic circuit B are in a conductive state, and the hydraulic circuit C is The state shown in FIG. 17 in the shut-off state can be switched to the state shown in FIG. 21 in which the hydraulic circuit A and the hydraulic circuit C are in the conducting state and the hydraulic circuit B is in the shut-off state.

  Also in the embodiment shown in FIG. 17, the same effect as that of the embodiment shown in FIG. 1 can be obtained. That is, the angular component forces of the bending reaction forces acting on the cam member 24 by the spring elements 16 of the two poppet valve elements 3 cancel each other, and the load of the moving operation of the cam member 24 can be reduced. It is possible to realize an ideal directional control valve device 2 that can be controlled with a simple control operation force and has no leakage loss when the valve is closed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various other embodiments can be adopted.

For example, the spring elements (valve springs) 16 and 31 are connected to the poppet valve member 7 and the driven member 15.
, 30 is inserted directly between the poppet valve member 7 and the driven members 15, 30, and a spring of the spring elements 16, 31 is partly attached to the link mechanism or the like. A force may be applied. As the valve-closing pressure contact force generating element, a magnet or the like using magnetic force may be used without depending on the valve spring using spring force. In short, it goes without saying that various applied variations can be applied if an angular component force characteristic equivalent to a linear characteristic with a set force of zero and a constant spring constant is obtained.

  Furthermore, in the above embodiment, the principle of the present invention has been described with an example of a three-circuit switching valve unit that switches between three-system circuits by two poppet valve elements 3, but a circuit-switching valve unit that switches between more multi-system circuits. In the case of configuring the circuit switching valve unit, the control operation force for each of the two poppet valve elements 3 out of the plurality of poppet valve elements 3 is determined as the mutual relationship of the opening and closing timings of the plurality of poppet valve elements 3 constituting the circuit switching valve unit. Of course, the same effect as in the above-described embodiment can be obtained as a whole if the canceling relationship is formed. That is, when switching the continuity relationship between multiple hydraulic circuits, it is configured as a directional control valve device that is switched by opening / closing control of four or more even-numbered poppet valve elements 3, and each of the even-numbered poppet valve elements 3 is configured. By applying the relationship of the above embodiment to the operation relationship between two poppet valve elements 3 as a mutual relationship between the operation timings, it is possible to reduce the operating force as a whole. In that case, as a cam mechanism 4 for giving an opening / closing motion to the plurality of poppet valve elements 3, two cam disks are sandwiched between valve unit blocks each having the poppet valve elements 3 arranged on a concentric circle around one central axis. By installing and integrally connecting the cam disks with a central shaft member, the poppet valve elements 3 can be opened and closed synchronously by the rotational movement of the cam disks.

1 direction control valve device 2 direction control valve device 3 poppet valve element 4 cam mechanism 5 housing member 7 poppet valve member 15 driven member 16 spring element (valve spring)
24 cam member 26 cam crest 30 driven member

Claims (1)

A directional control valve device that switches a conduction relationship between three or more hydraulic circuits by opening / closing control of a plurality of poppet valve elements and uses a cam mechanism to give an opening / closing motion to the plurality of poppet valve elements,
Each of the plurality of poppet valve elements is provided in a housing member, and is mounted on the poppet valve member so as to be movable in the axial direction of the poppet valve member. And a driven member that moves in the axial direction of the poppet valve member in response to pushing by the cam mechanism serving as a control input member, and is interposed between the poppet valve member and the driven member, the poppet valve member and the A spring element whose amount of deflection changes according to relative displacement with the driven member,
The cam mechanism has a cam member that drives two of the plurality of poppet valve elements together,
The cam member is configured so that when the amount of bending of the spring element of one of the two poppet valve elements increases, the amount of bending of the spring element of the other poppet valve element decreases. have a cam mountain to drive the poppet valve element,
The spring element has a linear characteristic with a substantially constant spring constant, and when the relative displacement between the poppet valve member and the driven member is zero, the amount of bending is substantially zero, and the poppet valve When the relative displacement between the member and the driven member is the maximum displacement, the poppet valve member and the driven member are interposed between the poppet valve member and the driven member so that the amount of deflection is the maximum deflection. Directional control valve device.

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