Patent Description:
A directional control valve normally has more than two flowing forms and is provided with more than two oil ports. Communication, cut-off and direction control of hydraulic oil circuits, as well as pressure relief and sequential action control can be achieved via controlling relative movements between a spool and a housing of the directional control valve.

In general, besides the spool and the housing, the directional control valve further includes a control system for controlling movements of the spool relative to the housing. According to the driving type of the control system, the directional control valve may be classified as manual directional control valve, mechanical directional control valve, solenoid directional control valve, hydraulic directional control valve and electro-hydraulic directional control valve. According to the positions of the spool in the valve body during operation of the spool and the number of communicating ways controlled by the directional control valve, the directional control valve may be classified as two-position two-way directional control valve, two-position three-way directional control valve, two-position four-way directional control valve, three-position four-way directional control valve, etc. According to the structural form of the directional control valve, the directional control valve may be classified as spool type directional control valve and rotary type directional control valve. <CIT> describes a control mechanism for a spool in a hydraulic valve.

For example, <FIG> illustrates an operation principle of a three-position four-way directional control valve in which movements of a spool can be controlled via a pilot oil line. The operation mode of the directional control valve includes:.

When the spool is in a middle operation position, an oil inlet port P of a main oil line, an oil return port T of the main oil line, a first oil port A and a second oil port B are not in fluid communication with each other; at the moment, the valve is in a neutral position, and an oil supply system connected to the oil inlet port P of the main oil line stops supplying oil.

When the spool is in a left operation position, the oil inlet port P of the main oil line is in fluid communication with the first oil port A, and the second oil port B is in fluid communication with the oil return port T of the main oil line.

When the spool is in the right operation position, the oil inlet port P of the main oil line is in fluid communication with the second oil port B, and the first oil port A is in fluid communication with the oil return port T of the main oil line.

The switches between above-mentioned different operation modes may be achieved via controlling two pilot valves (specifically, two pilot electric proportional pressure reducing valves) or via manual operation. For example, a manual actuator may be used here in an emergency or for manual testing. As shown in <FIG>, control oil lines (the dashed line) of the pilot valves are connected with the oil inlet port P0 of the pilot oil line and the oil return port T0 of the pilot oil line.

For example, <FIG> illustrates a spool type directional control valve, the directional control valve includes a first pilot valve <NUM>, a second pilot valve <NUM>, a connecting block <NUM>, a housing <NUM>, a spool assembly <NUM> and a manual actuator <NUM>. The first pilot valve <NUM> and the second pilot valve <NUM> may be pilot electric proportional pressure reducing valve, which are fixedly connected to the housing <NUM> via the connecting block <NUM> and located outside the housing <NUM>. The housing <NUM> is matched with the spool assembly <NUM> to form four fluid regions which are associated with an oil inlet port P of a main oil line, an oil return port T of the main oil line, a first oil port A and a second oil port B, respectively.

When the spool assembly <NUM> is in a neutral position, the four fluid regions are independent of each other and do not in fluid communication with each other.

When either of the first pilot valve <NUM> and the second pilot valve <NUM> is powered on, pressure oil will be output to push the spool assembly <NUM> to move axially. With the change of the position of the spool assembly <NUM>, the four fluid regions will be connected in two modes:.

When one pilot valve is powered on, the oil inlet port P of the main oil line is in fluid communication with the first oil port A, and the oil return port T of the main oil line is in fluid communication with the second oil port B, that is, P-A and B-T.

When the other pilot valve is powered on, the oil inlet port P of the main oil line is in fluid communication with the second oil port B, and the oil return port T of the main oil line is in fluid communication with the first oil port A, that is, P-B and A-T.

When both the pilot valves are powered off, the spool assembly <NUM> returns to the neutral position under restoring force of a spring and keeps still.

The above-mentioned movement process of the spool assembly <NUM> may also be controlled by the manual actuator <NUM>.

As shown in <FIG>, the spool assembly <NUM> includes a spool body <NUM>, a pull rod <NUM>, a left stop block <NUM>, a spring <NUM> and a right stop block <NUM>. The leftward movement of the left stop block <NUM> is restricted by the housing <NUM>, and the rightward movement of the right stop block <NUM> is restricted by the manual actuator <NUM>.

When the left side of the spool assembly <NUM> is pushed by the pressure oil, the right stop block <NUM> keeps still, the left stop block <NUM> with the spool body <NUM> together move to the right, and the spring <NUM> compresses under the pressure until the left stop block <NUM> and the right stop block <NUM> are in contact with each other (it can be learned that the axial displacement of the spool assembly <NUM> moving to the right is restricted by the gap distance between the left stop block <NUM> and the right stop block <NUM>).

When the right side of the spool assembly <NUM> is pushed by the pressure oil, the left stop block <NUM> keeps still, the right stop block <NUM> with the spool body <NUM> together move to the left, and the spring <NUM> compresses under the pressure until the right stop block <NUM> and the left stop block <NUM> are in contact with each other (it can be learned that the axial displacement of the spool assembly <NUM> moving to the left is restricted by the gap distance between the left stop block <NUM> and the right stop block <NUM>).

When there is no external force from the pilot valves applied to the spool assembly <NUM>, the spool body <NUM> remains in the neutral position under the action of the spring <NUM>.

In addition, the right end of the pull rod <NUM> is provided with a U-shaped open slot. If the pull rod <NUM> is pushed or pulled by other mechanical means via the U-shaped open slot, the spool assembly <NUM> may also be controlled to move in the same way as described above.

As shown in <FIG>, <FIG>, the main parts of the manual actuator <NUM> include a manual actuator body <NUM>, a catcher <NUM>, a shaft sleeve <NUM>, a threaded plug <NUM>, a sealing ring <NUM> and a handle <NUM>. The catcher <NUM> is provided with a cylindrical head <NUM> and a shaft <NUM>. The cylindrical head <NUM> is located in the U-shaped open slot described above for pushing and pulling the spool assembly <NUM> to move axially. An end of the shaft <NUM> which is away from the catcher <NUM> extends out of the manual actuator body <NUM> for connecting to the handle <NUM>.

Specifically, the catcher <NUM> is located in an inner cavity of the manual actuator body <NUM>. An end of the shaft <NUM> on which the handle <NUM> is mounted on is with a hexagonal cross section to make sure the catcher <NUM> and the handle <NUM> rotate synchronously. The shaft sleeve <NUM>, the threaded plug <NUM> and the sealing ring <NUM> are coaxially disposed between a mounting hole of the manual actuator body <NUM> and the shaft <NUM>. The catcher <NUM> and the shaft <NUM> may freely rotate relative to the manual actuator body <NUM> (and the shaft sleeve <NUM>). The catcher <NUM> may be mounted stably in the manual actuator body <NUM> by the threaded plug <NUM>. By the sealing ring <NUM>, the sealing performance of the connection position is ensured, and the flowing of hydraulic oil out of the manual actuator body <NUM> is avoided.

The operation process of the directional control valve includes:.

Generally, when the spool type directional control valve is controlled by the pilot valve in the electrical way, hysteresis is a very important parameter of evaluating performance of the directional control valve. Detailed analysis is carried out for understanding the reasons for the hysteresis, and it has been found that the reasons for the hysteresis are mainly due to viscosity and mechanical friction force between moving parts and fixed parts of the directional control valve. Moreover, it can be learned from the above description of the function of the actuator <NUM>, that is, when the spool assembly <NUM> is driven by the pilot valves to move, the catcher <NUM> and the handle <NUM> rotate synchronously with the spool assembly, at this moment, in addition to the friction force between the spool assembly <NUM> and the housing <NUM>, the manual actuator <NUM> applies additional friction force to the control of the pilot valve. This additional friction force is mainly caused by the following factors:.

Since the contact surfaces in the above factor a) and factor b) are normally in a steel-to-steel manner, the interaction force between the adjacent parts at the contact surfaces is not great, and the friction force caused by the above interaction may be ignored. However in the above factor c), since the contact surfaces between the catcher <NUM> and the sealing ring <NUM> make a steel-to-rubber contact, the friction force between the catcher <NUM> and the sealing ring <NUM> cannot be ignored, and it has an obvious impact on the increasing of hysteresis to the directional control valve.

Moreover, in the above factor c), the friction force between the catcher <NUM> and the sealing ring <NUM> is related to the operation pressure of the hydraulic oil in the manual actuator body <NUM>. The higher the operation pressure of the hydraulic oil is, the greater the friction force between the catcher <NUM> and the sealing ring <NUM> is, as a result, another performance problem is caused, that is:.

When the spool assembly <NUM> needs to be moved to the right, a first fluid region S1 (composed of the connecting block <NUM>, the housing <NUM> and the spool assembly <NUM>) located on the left side of the spool assembly <NUM> has a high pressure value, a second fluid region S2 (composed of the manual actuator body <NUM>, the housing <NUM> and the spool assembly <NUM>) on the right side of the spool assembly <NUM> is fluidly connected to an oil tank, that is, the oil hydraulic pressure in the first fluid region S1 is higher than the oil hydraulic pressure in the second fluid region S2 (at this moment, the pressure of the second fluid region S2 is substantially equal to atmospheric pressure).

When the spool assembly <NUM> needs to be moved to the left, the pressure relationship of the above two fluid regions S1 and S2 turns to be opposite, that is, the oil hydraulic pressure in the first fluid region S1 is lower than the oil hydraulic pressure in the second fluid region S2.

Referring to <FIG>, when the oil hydraulic pressure in the second fluid region S2 is higher, as the catcher <NUM> is subjected to a greater lateral force F shown by the arrow in <FIG>, the friction force between the catcher <NUM> and the sealing ring <NUM> becomes very great. As a result, the friction force between the catcher <NUM> and the sealing ring <NUM> when the spool assembly <NUM> moving to the left and the friction force between the catcher <NUM> and the sealing ring <NUM> when the spool assembly <NUM> moving to the right are significantly different, therefor the hysteresis of the directional control valve become asymmetrical when the spool assembly <NUM> moving in different directions.

Therefore, how to reduce the hysteresis of the directional control valve and how to avoid the asymmetrical hysteresis of the directional control valve when the spool assembly moving in different directions are urgent technical problems to be solved by those skilled in the art at present.

Thus, a purpose of the present invention is to provide an actuator used for controlling the movement and displacement of a spool, and a spool type directional control valve equipped with the actuator, so that hysteresis of the directional control valve can be reduced, and asymmetrical hysteresis of the directional control valve when the spool moving in different directions can also be avoided.

In order to achieve the foregoing purpose, the present invention provides the following technical solutions.

An actuator used for controlling the movement and displacement of the spool is provided. The actuator includes:.

In the actuator, the second connecting portion further includes a second limiting portion therein, and the first limiting portion, the avoidance slot and the second limiting portion are connected sequentially in a circumferential direction;.

Optionally, in the actuator, the catcher is provided with a through hole, the shaft extends into the through hole, and a sidewall of the through hole is provided with the second connecting portion; and/or
the first connecting portion is a columnar structure.

Optionally, in the actuator, the sidewall of the through hole is provided with two or more the second connecting portions in a circumferential direction.

Optionally, in the actuator, an end of the shaft body is provided with an open groove; and
the control member is a connecting block located in the open groove, and one end or two ends of the connecting block extend out of the open groove in a radial direction of the shaft body to cooperate with the second connecting portion.

Optionally, the actuator further includes:.

Optionally, in the actuator, the bottom plate structure is provided with an axial hole which is matched with an end of the shaft body.

Optionally, the actuator further includes a mechanism body, and the mechanism body is provided with an internal cavity capable of accommodating the catcher;.

Optionally, in the actuator, a limiting structure used for mounting the bottom plate structure is disposed in the mechanism body, and the limiting structure is connected to the bottom plate structure in a circumferential direction.

A spool type directional control valve which is provided with the actuator described above.

Optionally, the spool type directional control valve further includes:.

It may be learned from the technical solutions that in the spool type directional control valve and the actuator thereof provided by the present invention, since the shaft connected to the operation mechanism is separated from the catcher which is directly connected to the spool, the operation process of the spool being controlled to move by the actuator is separated from the operation process of the spool being controlled to move by other means (for example, by a pilot valve).

That is to say, when the spool is controlled to move by other control means (such as a pilot valve) rather than by the actuator, the catcher moves with the spool together. However, since the catcher is provided with the avoidance slot, and the maximum rotation angle c of the control member in the avoidance slot is greater than the first angle a, so that the motion of the catcher will not drive the shaft and the operation mechanism to move.

It may be learned that the actuator does not have any effect on the operation processes when the valve is controlled to move and displace by other means; moreover, by the actuator, the problem of the hysteresis caused by friction between the catcher and the sealing ring during the rotation of the shaft can be avoided, and the asymmetrical hysteresis of the directional control valve when the spool moving in different directions described in the "BACKGROUND" can also be avoided completely.

In order to explain the prior art and the technical solutions of the present invention more clearly, the drawings needed in the description of the prior art and embodiments of the present invention will be briefly introduced as below. Obviously, the drawings in the following description are only showing some embodiments of the present invention, and other similar drawings can be obtained without creative work by those skilled in the art based on drawings of the present invention.

Embodiments of the present invention provide an actuator for controlling movement and displacement of a spool and a spool type directional control valve provided with the actuator, by which hysteresis of the directional control valve can be reduced, and the asymmetrical hysteresis of the directional control valve when the spool moving in different directions can also be avoided.

Embodiments of the present invention will be clearly and completely described with referring to the accompanying drawings of the present application. Apparently, the described embodiments are a part of rather than all of embodiments of the present invention.

Referring to <FIG>, embodiments of the present invention provide an actuator for controlling movement and displacement of a spool <NUM>. The actuator includes a catcher <NUM> and a shaft <NUM>.

The catcher <NUM> is provided with a first connecting portion <NUM> and a second connecting portion <NUM>. The first connecting portion <NUM> is used for connecting to the spool <NUM>, and the second connecting portion <NUM> includes a first limiting portion <NUM> and an avoidance slot <NUM> which are connected in a circumferential direction ("the circumferential direction" in the present invention specifically refers to "a direction along a circumference", the circumference refers to a circular trajectory centered on a rotation axis of the shaft <NUM> and located in a plane perpendicular to the rotation axis of the shaft <NUM>).

The shaft <NUM> includes a shaft body <NUM> and a control member <NUM>, the shaft body <NUM> is used for connecting to an operation mechanism <NUM>, and the shaft <NUM> can be driven by the operation mechanism <NUM> to rotate back and forth in a preset range.

When the shaft <NUM> is driven by the operation mechanism <NUM> to rotate in a forward direction:.

Firstly, the control member <NUM> rotates forward in the avoidance slot <NUM> to a position where the control member <NUM> abuts against the first limiting portion <NUM>; then the control member <NUM> drives the first limiting portion <NUM> to rotate continuously, so that the shaft <NUM> drives the catcher <NUM> to rotate forward by the control member <NUM>; at this moment, the catcher <NUM> drives the spool <NUM> to move forward until the rotation angle of the catcher <NUM> reaches to a first angle a from the above described abutting position, and the spool <NUM> arrives at a first working position by moving forward.

It should be noted that, in a specific implementation, the valve provided with the actuator may also be controlled to work by other means (for example, controlled by a pilot valve). When the catcher <NUM> is controlled by other means to rotate and drive the spool <NUM> to move to the first working position, the control member <NUM> can rotate freely in the avoidance slot <NUM>. In an embodiment not according to the claimed invention, in order to prevent the catcher <NUM> from interfering with the control member <NUM> during operation processes controlled by other means, the maximum rotation angle c of the control member <NUM> in the avoidance slot <NUM> should not be less than the first angle a, that is, c ≥ a (a and c are both angle values, regardless of positive or negative). In the extreme case when c = a, it may be ensured that the control member <NUM> will not interfere with the catcher <NUM> by accurate structural design, so that the shaft <NUM> and the operation mechanism <NUM> will not be driven to move.

It should be noted that, if the actuator is used in a switch valve, the switch valve may be opened or closed when the spool <NUM> moves forward to a first working position; if the actuator is used in a proportional valve, an effect of adjusting the medium flow rate/pressure in proportion can be achieved in a process that the spool <NUM> moves forward to a first working position, and at the moment, "the first working position" is not only a limit position of the movement of the spool, but also corresponds to a limit value in the above-mentioned adjusting process of the proportional valve.

It may be learned that in the actuator, since the shaft <NUM> connected to the operation mechanism <NUM> is separated from the catcher <NUM> which is directly connected to the spool <NUM>, the operation process in which the spool is controlled to move by the actuator is separated from the operation process in which the spool is controlled to move by other means (for example, by a pilot valve).

That is to say, when the spool <NUM> is controlled to move by other control means (such as a pilot valve) rather than by the actuator, the catcher <NUM> moves with the spool <NUM> together. However, as the catcher <NUM> is provided with an avoidance slot <NUM>, and the maximum rotation angle c of the control member <NUM> in the avoidance slot <NUM> is greater than or equal to the first angle a, when c > a, the moving catcher <NUM> will not touch the control member <NUM>, so that the shaft <NUM> and the operation mechanism <NUM> will not be driven to move. Even in the extreme case when c = a, it may be ensured that the control member <NUM> does not interfere with the catcher <NUM> by accurate structural design, so that the shaft <NUM> and the operation mechanism <NUM> will not be driven to move.

It may be learned that the actuator does not have any impact on the operation processes when the valve provided with the actuator is controlled to move and displace by other means. Moreover, by using the actuator, the problem of the hysteresis caused by friction force between the rotating shaft <NUM> and the sealing ring <NUM> can be avoided, and the asymmetrical hysteresis of the directional control valve when the spool moving in different directions described in the "BACKGROUND" can also be avoided completely.

According to the claimed invention, when the actuator is applied in a three-position directional control valve, a second limiting portion <NUM> is disposed in the second connecting portion <NUM>. The first limiting portion <NUM>, the avoidance slot <NUM> and the second limiting portion <NUM> are connected sequentially in a circumferential direction. The maximum rotation angle c described above should not be less than a sum of the first angle a and the second angle b, that is, c ≥ a + b (a, b and c are all angle values, regardless of positive or negative). Moreover, when the shaft <NUM> rotates backward:.

Firstly, the control member <NUM> rotates backward in the avoidance slot <NUM> to a position where the control member <NUM> abuts against the second limiting portion <NUM>; then the control member <NUM> drives the second limiting portion <NUM> to rotate continuously, so that the shaft <NUM> drives the catcher <NUM> to rotate backward via the control member <NUM>, and at this moment, the catcher <NUM> drives the spool <NUM> to move backward until the rotation angle of the catcher <NUM> reaches to a second angle b from the above described abutting position, and the spool <NUM> arrives at a second working position by moving backward.

It should be noted that, in a specific implementation, the valve provided with the actuator may also be controlled to work by other means (for example, by a pilot valve). When the catcher <NUM> is controlled by other means to rotate and drive the spool <NUM> to move to the second working position, the control member <NUM> can rotate freely in the avoidance slot <NUM>. In order to prevent the catcher <NUM> from interfering with the control member <NUM> during operation processes controlled by other means, the maximum rotation angle c of the control member <NUM> in the avoidance slot <NUM> should not be less than the second angle b.

In addition, the process that the spool moves to the first working position and the process that the spool moves to the second working position are two independent operation processes, and the rotation directions of the catcher <NUM> in the two operation processes are opposite, so that a maximum rotation angle c of the control member <NUM> in the avoidance slot <NUM> should not be less than a sum of the first angle a and the second angle b, that is, c ≥ a + b (a, b and c are all angle values, regardless of positive or negative). In the extreme case when c = a+b, it can be ensured that the control member <NUM> does not interfere with the catcher <NUM> by accurate structural design, so that the shaft <NUM> and the operation mechanism <NUM> will not be driven to move.

It should be noted that, if the actuator is used in a switch valve, the switch valve is opened or closed when the spool <NUM> moves backward to a second working position; if the actuator is used is a proportional valve, an effect of adjusting the medium flow rate/pressure in proportion can be achieved in a process that the spool <NUM> moves backward to a second working position, and at the moment, "the second working position" is not only another limit position of the movement of the spool, but also corresponds to another limit value in the above-mentioned adjusting process of the proportional valve.

In a specific implementation, referring to <FIG>, the catcher <NUM> is provided with a through hole, and the shaft <NUM> extends into the through hole. A sidewall of the through hole is provided with the second connecting portion <NUM>. Preferably, the sidewall of the through hole is provided with two or more second connecting portions <NUM> in a circumferential direction, so as to facilitate a stable connection between the shaft <NUM> and the catcher <NUM>.

In a specific implementation, the above-mentioned first connecting portion <NUM> of the catcher <NUM> is a columnar structure, and correspondingly, a pull rod <NUM> located at an end of the spool <NUM> is provided with an open slot matched with the columnar structure. For example, the open slot may be a U-shaped open slot. Therefore, a transmission connection between the catcher <NUM> and the spool <NUM> is achieved. However, it is not limited thereto, and in other specific embodiments, other connection structures may be used between the catcher <NUM> and the spool <NUM>. For example, the catcher <NUM> and the spool <NUM> may be hinged by a pin and through hole structure.

Specifically, referring to <FIG>, an end of the shaft body <NUM> is provided with an open groove <NUM> (a radial through hole in general). The control member <NUM> is a connecting block located in the open groove <NUM>, and one end or two ends of the connecting block extend out of the open groove <NUM> in a radial direction of the shaft body <NUM> to cooperate with the second connecting portion <NUM>.

Referring to <FIG>, in a specific implementation, the catcher <NUM> is located in the cavity of the mechanism body <NUM>, an end of the shaft <NUM> is connected to the operation mechanism <NUM> (such as a handle), and the other end of the shaft <NUM> extends into the mechanism body <NUM> through the sidewall of the mechanism body <NUM>. The sidewall of the mechanism body <NUM> is provided with a threaded mounting hole, and the shaft <NUM> is mounted in the mounting hole via a threaded plug <NUM>, and the sealing is achieved by a sealing ring <NUM>. In order to limit the axial position of the shaft <NUM>, an annular limiting slot is formed on the shaft <NUM>. A gasket <NUM> is mounted in the annular limiting slot, and the gasket <NUM> abuts against the threaded plug <NUM>, so that it can be achieved to limit the axial position between the shaft <NUM> and the threaded plug <NUM> by the gasket <NUM>, and the shaft <NUM> is prevented from being separated from the mechanism body <NUM> in the axial direction.

Further, referring to <FIG>, the actuator further includes a bottom plate structure <NUM> and an elastic member <NUM>. The bottom plate structure <NUM> is provided with a limiting slot <NUM> The elastic member <NUM> is located in the shaft body <NUM> (for details, please refer to <FIG> in which an internal accommodating groove <NUM> is shown). The elastic member <NUM> is used for providing an axial preload force for the control member <NUM>, so that the control member <NUM> is pressed into the limiting slot <NUM>, and therefore, the shaft <NUM> and the operation mechanism <NUM> connected to the shaft <NUM> keep still automatically, and self-locking is achieved.

When the operation mechanism <NUM> controls the shaft <NUM> to rotate, the control member <NUM> will compress the elastic member <NUM>, separate from the limiting slot <NUM> of the bottom plate structure <NUM>, and continue to rotate with the shaft <NUM> together, so that the catcher <NUM> is controlled to drive the spool to move.

When the operation mechanism <NUM> controls the shaft <NUM> to rotate back to the neutral position, under the action of the elastic member <NUM>, the control member <NUM> returns back into the limiting slot <NUM> of the bottom plate structure <NUM> automatically to achieve self-lock, so that the operation mechanism can be surely kept at the neutral position stably and does not rotate at random.

Specifically, the elastic member <NUM> may be a compressing spring. A plate <NUM> is also disposed between the compressing spring and the control member <NUM>. Via the plate <NUM>, the compressing spring can be limited in the internal accommodating groove <NUM> of the shaft body <NUM>, and it is beneficial to transmit the restoring force of the compressing spring to the control member <NUM> stably to ensure the stable operation of the control member <NUM> and avoid jamming.

In a specific implementation, the bottom plate structure <NUM> is further provided with an axial hole <NUM> which is matched with an end of the shaft body <NUM>, so that the position of the shaft <NUM> can be limited by the axial hole <NUM> of the bottom plate structure <NUM>, which is beneficial to improve coaxiality of the shaft <NUM> and the mounting hole of the mechanism body, and ensure the stability and working reliability during manual operation of the actuator.

In a specific implementation, the bottom plate structure <NUM> may be an independent part mounted in the mechanism body <NUM>, or the bottom plate structure <NUM> may be a similar structure having a limiting slot <NUM> and being formed on the inner wall of the mechanism body <NUM>.

In a specific implementation, the actuator further includes a pin <NUM>. The control member <NUM> is mounted in the open groove <NUM> of the shaft body <NUM> by the pin <NUM>. Either the control member <NUM> or the shaft body <NUM> is provided with a strip-shaped hole matched with the pin <NUM>, and the length direction of the strip-shaped hole is parallel to the central axis of the shaft body <NUM>. For example, referring to <FIG>, the control member <NUM> is provided with a strip-shaped hole <NUM> for the pin <NUM> to pass through, and the pin <NUM> is in clearance fit with the strip-shaped hole <NUM>, so that the control member <NUM> is movable in the length direction of the strip-shaped hole <NUM> (i.e., the axial direction of the shaft body <NUM>). The shaft body <NUM> is provided with two mounting holes <NUM> respectively on both sides of the open groove <NUM>, and the mounting holes <NUM> are in interference fit with the pin <NUM>, so as to ensure that the control member <NUM> will not detach from the shaft <NUM> under working conditions.

It should be noted that, referring to <FIG>, the cross section of the limiting slot <NUM> may have a cross section in V shape, isosceles trapezoid shape or arc shape. The above-mentioned axial hole <NUM> is a circular blind hole coaxial with the shaft body <NUM>. Referring to <FIG>, the above-mentioned open groove <NUM> may be a U-shaped slot, and its center plane is the center plane of the shaft body <NUM>. However, it is not limited thereto, and in other embodiments, a technician may adopt other similar structures to achieve the same function, and therefore, the above-mentioned specific structures are not specifically limited in the present invention.

In a specific implementation, the above-mentioned actuator may be used in a newly designed directional control valve. In addition, a conventional actuator in a directional control valve may be detached and be replaced with the above-mentioned actuator of the present invention, so that the directional control valve can be improved and upgraded, and the cost can be saved.

Further, the above-mentioned actuator of the present invention further includes a mechanism body <NUM>. Referring to <FIG>, <FIG>, the mechanism body <NUM> is provided with an inner cavity capable of accommodating the catcher <NUM>. The bottom plate structure <NUM> is fixed in the inner cavity. An end of the shaft <NUM> extends into the inner cavity and penetrates through the catcher <NUM> to cooperate with the bottom plate structure <NUM>.

Preferably, a limiting structure used for mounting the bottom plate structure <NUM> is disposed in the mechanism body <NUM>. For example, referring to <FIG>, two sides of the bottom plate structure <NUM> are provided with connection slots <NUM>, and an inner wall of the mechanism body <NUM> is provided with connection protrusions. Via the connection slots <NUM> and the connection protrusions, the bottom plate structure <NUM> can be fixedly mounted in the mechanism body and keep still. And the axial position of the bottom plate structure <NUM> can be limited via the shaft <NUM>. For example, a limiting structure used for mounting the bottom plate structure <NUM> is provided in the mechanism body <NUM>, the limiting structure is a groove hole specifically, and the bottom plate structure <NUM> is provided with connection protrusions or pins matched therewith. However, it is not limited thereto, and in other specific embodiments, the circumferential connection between the limiting structure and the bottom plate structure <NUM> may also be achieved in other ways.

In a specific implementation, preferably, the control member <NUM> has a wedge-shaped block structure, and a thinner part of the control member <NUM> is matched with the limiting slot <NUM> of the bottom plate structure <NUM>. However, it is not limited thereto, and in other specific embodiments, the control member <NUM> may also be designed as a columnar member, which may have a cross section in triangular shape, isosceles trapezoid shape, elliptical shape, circular shape, or other structure forms. It is not specifically limited thereto in the present invention, as long as the control member <NUM> can achieve the above-mentioned functions of abutting and driving, connection limiting, etc..

In a specific implementation, the operation mechanism <NUM> is a long handle, and an end of the control member <NUM> is provided with a polygonal mounting hole. Correspondingly, the cross section of the connection end <NUM> (for connecting to the operation mechanism <NUM>) of the shaft body <NUM> is with a polygonal shape (such as hexagon), so that the rotation can be controlled by the operation mechanism <NUM>.

The embodiments of the present invention further provide a spool type directional control valve, and the spool type directional control valve is provided with the above-mentioned actuator.

Specifically, the spool type directional control valve further includes an operation mechanism <NUM>, a spool <NUM> and pilot valves. The operation mechanism <NUM> is connected to the shaft body <NUM> of the actuator, and the operation mechanism <NUM> is used for controlling the rotation of the shaft <NUM>. The spool <NUM> is provided with a pull rod <NUM> which is used for connecting to the first connecting portion <NUM> of the catcher <NUM> of the actuator. The pilot valves are used for controlling the movement and displacement of the spool <NUM>.

In a specific implementation, referring to <FIG> and <FIG>:
Referring to <FIG>, a normal position L0 of the operation mechanism <NUM> corresponds to a neutral position.

Referring to <FIG>, the control member <NUM> is just in contact with the second limiting portion <NUM> of the catcher <NUM> when the operation mechanism <NUM> is controlled to rotate rightward by a certain angle, for example, from the position L0 to the position L1 shown in <FIG>, wherein the rotation angle is b', b' = b + Δb (Δb ≥ <NUM>, and b is the second angle described above);.

Referring to <FIG>, the operation mechanism <NUM> is continuously controlled to rotate rightward by the angle b (the second angle described above), for example, the operation mechanism <NUM> shown in <FIG> rotates from the position L1 to the position L2, and the spool <NUM> is driven to move rightward from the neutral position to the second working position.

Correspondingly, when the spool is controlled to move leftward to the first working position via controlling the operation mechanism <NUM> to rotate leftward by a certain angle from the normal position shown in <FIG>, the process is opposite, that is:
the control member <NUM> is just in contact with the first limiting portion <NUM> of the catcher <NUM> when the operation mechanism <NUM> is controlled to rotate leftward by a certain angle, wherein when the rotation angle is a', a' = a + Δa ( Δa ≥ <NUM>, a is the first angle described above).

The operation mechanism <NUM> is continuously controlled to rotate leftward by the angle a (the first angle described above), and the spool <NUM> is driven to move leftward from the neutral position to the first working position.

Preferably, the value ranges of the first angle a and the second angle b are both between <NUM>° - <NUM>°, the value ranges of Δa and Δb are both between <NUM>° - <NUM>°, preferably Δa and Δb are both greater than zero, so that when the spool <NUM> is controlled by other control means (such as pilot valve) rather than by the actuator, the interference between the catcher <NUM> and the control member <NUM> are avoided. For example, in a specific embodiment, a = b =<NUM>°, and Δa = Δb =<NUM>°.

It should be noted that the maximum rotation angle of the control member <NUM> in the avoidance slot <NUM> of the catcher <NUM> is c, and c = a' + b' = a + Δa + b + Δb. When the spool <NUM> is controlled by other control means (such as pilot valve) rather than by the actuator to move, the catcher <NUM> moves with the spool <NUM> together. However, since the catcher <NUM> is provided with the above-mentioned avoidance slot <NUM>, the moving catcher <NUM> will not be in contact with the control member <NUM>, so that the shaft <NUM> and the operation mechanism <NUM> will not be driven to move. It may be learned that the actuator will not bring any impact when the valve is controlled to move and displace by other means; moreover, by using the actuator, the problem of hysteresis caused by friction between the shaft <NUM> and the sealing ring <NUM> during the rotation of the shaft <NUM> can be avoided, and the asymmetrical hysteresis of the directional control valve when the spool moving in different directions can also be avoided completely.

In conclusion, the spool type directional control valve provided by the present invention can be applied to various hydraulic machines such as engineering machinery, agricultural machinery, mining machinery and the like.

Finally, it also should be noted that in the present invention, the relationship terms, such as first and second, are merely herein distinguish an entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship of order between these entities of operations. Moreover, the terms "comprising", "including" or any other variant thereof are not intended to cover a non-exclusive inclusion, such that processes, methods, articles or devices, which include a series of elements, include not only those elements, but also other elements which are not listed expressly, or include the inherent elements of the processes, methods, articles or devices. In the case without any more restrictions, the element defined by the sentence "comprising a. " does not exclude the presence of additional identical elements in the processes, methods, articles or devices that include the element.

Various embodiments in the present specification are described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts in the embodiments can be referred to each other.

Claim 1:
An actuator, used for controlling the movement and displacement of a spool (<NUM>), wherein, the actuator comprises:
a catcher (<NUM>), provided with a first connecting portion (<NUM>) and a second connecting portion (<NUM>), wherein the first connecting portion (<NUM>) is used for connecting to the spool (<NUM>), and the second connecting portion (<NUM>) comprises a first limiting portion (<NUM>) and an avoidance slot (<NUM>) which are connected in a circumferential direction; and
a shaft (<NUM>), comprising a shaft body (<NUM>) and a control member (<NUM>), wherein the shaft body (<NUM>) is used for connecting to an operation mechanism (<NUM>) and is configured to be driven to rotate by the operation mechanism (<NUM>) so as to enable the control member (<NUM>):
to abut against the first limiting portion (<NUM>), and drive the catcher (<NUM>) to rotate forward by a first angle a via the first limiting portion (<NUM>), so as to drive the spool (<NUM>) to move forward to a first working position; and
to rotate freely in the avoidance slot (<NUM>),
the second connecting portion (<NUM>) further comprises a second limiting portion (<NUM>), and the first limiting portion (<NUM>), the avoidance slot (<NUM>) and the second limiting portion (<NUM>) are connected sequentially in a circumferential direction;
the control member (<NUM>) is capable of abutting against the second limiting portion (<NUM>), and driving the catcher (<NUM>) to rotate backward by a second angle b via the second limiting portion (<NUM>), so as to drive the spool (<NUM>) to move backward to a second working position;
characterized in that
a maximum rotation angle c of the control member (<NUM>) in the avoidance slot (<NUM>) is not less than a sum of the first angle a and the second angle b.