JPH0341710B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric switching valve, and particularly to an electric switching valve that can be made smaller and lighter.

[Conventional technology]

For example, a cylindrical sleeve with multiple ports opened at predetermined intervals in the axial direction to which pressurized fluid piping is connected is used as a valve to control pressurized fluid acting on fluid pressure operated equipment such as a cylinder device. A so-called spool valve is a so-called spool valve in which a spool of different diameters that can freely slide in the axial direction is located inside the spool, and selective connection of multiple ports can be controlled by displacing the spool in the axial direction. Are known.

By the way, as a drive means for such a spool valve, an electromagnetic structure consisting of a solenoid, a movable iron core and a fixed iron core that are housed in the solenoid so as to be freely displaceable in the internal axial direction and are locked to the spool is used. A method is known in which the displacement of the spool is controlled by the thrust generated in the iron core when energized.

[Problem that the invention seeks to solve]

However, when a spool valve is operated, the stroke of the spool is generally large, and on the other hand, the thrust of the core driven by a solenoid is in principle inversely proportional to the square of the stroke. When driving, it is necessary to increase the number of turns of the conductor that makes up the solenoid, which increases the size of the electromagnet and increases power consumption.As a result, the overall size of the spool valve to which the electromagnet is attached is required. The problem is that it is unavoidable that the size becomes larger than this.

In addition, when driving the spool with an electromagnet, for example, the return spring and the iron core work together to realize only a simple operation such as moving the spool from one end of the stroke to the other. There is also the problem that it is difficult to implement various types of control, such as stopping the system at any time.

An object of the present invention is to provide an electric switching valve that can be reduced in size.

Another object of the present invention is to provide an electric switching valve that can easily implement various controls.

Still another object of the present invention is to provide an electric switching valve that has a small number of parts, has a simple structure, and is easy to assemble.

[Means for solving problems]

The electric switching valve of the present invention includes an electric motor that can control the rotation angle of an output shaft, a valve body that controls fluid through axial displacement, and a valve body that is interposed between the output shaft of the electric motor and the valve body. and a displacement converting means that directly converts the rotational displacement of the output shaft into a linear displacement and transmits it to the valve body, and the displacement converting means is a cam with a constant diameter that is locked to the output shaft and passes through the output shaft. and is locked to the valve body at all times at two locations on the diameter including the output shaft.
The cam follower is linearly displaced by slidingly contacting and following the cam.

[Effect]

According to the above-mentioned means, even in the case of a spool in which the valve body moves a long distance in the axial direction, it is not necessary to increase the torque at the output shaft of the electric motor more than necessary, and the electric motor and the electric switching to which the electric motor is attached do not need to be increased more than necessary. The valve can be made smaller.

In addition, the cam, which is fixed to the output shaft of the electric motor and rotates, and the cam follower, which converts the rotational displacement of this cam into linear displacement and transmits it to the valve body, are in constant contact at two points on the diameter including the output shaft. Therefore, by stopping or slightly moving the output shaft of the motor at any rotation angle, the valve body can be stopped at any position in the stroke of the valve body, maintained at any position, and even the output shaft can be adjusted without causing backlash. The valve body can be displaced in proportion to the rotation angle of the valve body, and various controls can be easily realized.

In addition, the cam, which is fixed to the output shaft of the electric motor and rotates, and the cam follower, which converts the rotational displacement of this cam into linear displacement and transmits it to the valve body, are in constant contact at two points on the diameter including the output shaft. Therefore, shearing force in a direction intersecting the displacement direction of the valve body and cam follower does not act on the cam follower or the valve body. Therefore, there is no need to insert an extra member between the cam follower and the valve body to avoid the generation of the shearing force, and the structure is simplified by reducing the number of parts, and the assembly work is also simplified. becomes easier.

〔Example〕

FIG. 1 is a sectional view showing the main parts of an electric switching valve according to an embodiment of the present invention at one switching position, and FIG. 2 is a sectional view of the portion indicated by the line - in FIG. Further, FIG. 3 is a sectional view illustrating a state in which the electric switching valve of this embodiment is operated to another switching position, and FIG.
FIG.

The electric switching valve 1 of this embodiment has a main body block 2.
and a control block 3 connected to the main body block 2. Inside the main body block 2, a cylindrical sleeve 4 is inserted in the axial direction.

In the main body block 2 into which the sleeve 4 is inserted,
Multiple ports in the direction crossing the axis of the sleeve 4
IN, port OUT1, port OUT2, port
EXH1 and port EXH2 are bored, and the inner end of each port passes through the wall surface of the sleeve 4 and communicates with the inside of the sleeve 4.

Inside the sleeve 4 is a small diameter spool shaft 5a.
A spool is integrally fixed to the spool shaft 5a at predetermined intervals, and is made up of a plurality of large-diameter valve portions 5b, 5c, and 5d, the outer periphery of which slides freely on the inner periphery of the sleeve 4. 5 (valve body) is accommodated in a slidable manner in the axial direction, and inside the sleeve 4, a plurality of fluid chambers A and a fluid chamber B are separated by a plurality of valve portions 5b, 5c, and 5d of the spool 5. has been done.

The inner circumferential surface of the sleeve 4 and the outer circumferential surfaces of the plurality of valve parts 5b, 5c, and 5d of the spool 5 are each polished to a mirror-like finish, and the distance between them is several μm or less. As a result, the spool 5 can be smoothly displaced in the axial direction, and the fluid between the inner circumferential surface of the sleeve 4 and the outer circumferential surfaces of the plurality of valve parts 5b, 5c, and 5d of the spool 5 can be prevented. Leakage is prevented.

On the outer periphery of the sleeve 4 inserted into the main body block 2, there are a plurality of ports IN and OUT formed through the walls of the main body block 2 and the sleeve 4.
1. Multiple O-rings 6 are installed in positions that sandwich OUT2, EXH1, and EXH2, and each port
The fluid flowing through IN, OUT1, OUT2, EXH1, and EXH2 is prevented from leaking through the space between the outer periphery of the sleeve 4 and the main body block 2.

On the other hand, inside the control block 3, there is an operation space 3.
A is formed, and one end of the spool shaft 5a projects from the main body block 2 side.

Further, inside the control block 3, an output shaft 7a protruding into the operating space 3a is provided, and a spool shaft 5a is provided.
The electric motor 7 is installed in a position perpendicular to the direction.

This electric motor 7 is composed of, for example, a pulse motor, and is configured such that the rotational direction and rotation angle of the output shaft 7a can be arbitrarily controlled by a control signal commanded from the outside via a cable 7b. .

The output shaft 7a of the electric motor 7 has the operating space 3a.
A cam 8 having an elliptical outer shape, for example.
(displacement converting means) is locked, and the output shaft 7
It is constructed so that it can be rotated at any time by a desired angle in a desired direction by the rotational force of a.

Further, inside the operating space 3a, a cam follower 9 (displacement converting means) having a U-shaped outer shape and having one end of the spool shaft 5a locked is provided. A plurality of abutting portions 9a and a plurality of abutting portions 9b facing each other in the direction
By slidingly contacting the outer periphery of the cam 8, the rotational displacement of the cam 8 is converted into a linear displacement in the axial direction of the spool 5 via the cam follower 9, and the spool 5 is rotated via the spool shaft 5a. It is driven in the direction.

In this case, the cam 8, as shown in FIG.
It has a non-perfect circular shape with a minimum diameter a and a maximum diameter b on a straight line passing through the center of rotation, that is, the center of the output shaft 7a of the electric motor 7, and the direction of the minimum diameter a and maximum diameter b is the direction of the spool 5. At a position parallel to the axial direction, the minimum diameter a and the maximum diameter b of the cam 8 are configured to contact contact portions 9a and 9b of the U-shaped cam follower 9 at the same time. That is, the sum T of the minimum diameter a and the maximum diameter b of the cam 8
is set to be approximately equal to the distance between the contact portions 9a and 9b of the cam follower 9. Even at any position where the direction of the minimum diameter a and the maximum diameter b is not parallel to the axial direction of the spool 5, the shape of the cam 8 is such that the center of the output shaft 7a is in contact with the corresponding portions 9a and 9b of the cam follower 9 at the same time. The radial dimension of the spool 5 is approximately constant, and the spool 5 is shaped like a T, and the axial position of the spool 5 is regulated by the rotational position of the cam 8. Further, the cam follower 9 can be freely displaced with respect to the cam 8 in directions other than the axial direction of the spool 5.

Furthermore, since the cam 8 has a non-perfect circular shape with the above-mentioned profile dimensions, the cam follower 9 at the abutment position of the cam 8 and the cam follower 9 is more difficult to maintain than a perfect circular eccentric cam, for example. The deviation from the axis will be minimal.

The end of the sleeve 4 that opens on the side opposite to the control block 3 is closed by a lid 10 that is secured to the main body block 2, and a lid 10 that closes the operating space 3a is provided on the end surface of the control block 3. 12 is installed. If necessary, a spring 1 is installed between the lid 10 and the spool 5 provided inside the sleeve 4.
1a, and in this case, the spool 5 is always urged toward the control block 3 so that the contact portion 9b of the cam follower 9 is always in contact with the outer periphery of the cam 8. can do.

A lid 12 is attached to the end face of the control block 3 to close the operating space 3a.

A spacer 13 is interposed between the lid body 12 and the electric motor 7, and the electric motor 7 inserted from the end and incorporated is stably fixed.

Further, the cover body 12 is provided with a bush 12a made of rubber or the like, and a cable 7b connected to the electric motor 7 and transmitting electric power, control signals, etc.
is inserted into the bush 12a, pulled out to the outside, and connected to a control device (not shown).

The operation of this embodiment will be explained below.

In this embodiment, as an example of control by the electric switching valve 1, a case will be described in which the operation of the cylinder device 14 is controlled.

In other words, the port provided in main body block 2
IN is connected to a fluid pressure source (not shown), and a plurality of ports OUT1 and OUT2 are connected to fluid chambers 14d and 14 separated by a piston 14c inside the cylinder device 14 via piping 14a and 14b.
It is connected to 4e.

Further, a piston rod 14f whose one end protrudes outside the cylinder device 14 is connected to the piston 14c of the cylinder device 14.

First, the output shaft 7a of the electric motor 7 is controlled by a control signal commanded from the outside via the cable 7b.
As shown in the figure and FIG. 2, when the cam 8 is rotated until the portion with the minimum diameter a is positioned on the side of the main body block 2, the spool 5 is moved together with the cam follower 9, which is displaced following the cam 8. Move to the position closest to the control block 3 side, and press the valve part 5b.
Ports OUT2 and EXH2 are in communication via the fluid chamber A formed between the valve parts 5c and 5c, and at the same time, the ports OUT2 and EXH2 are in communication via the fluid chamber A formed between the valve parts 5c and 5d.
IN and port OUT1 are brought into communication.

The fluid pressure applied to the port IN from a fluid pressure source (not shown) is applied to the valve portions 5c and 5 of the spool 5.
Fluid chamber B between d, port OUT1, piping 14a
acts on the fluid chamber 14d of the cylinder device 14 through the piston 14c, and a thrust is generated in the direction of drawing the piston rod 14f into the piston 14c.
The fluid inside the fluid chamber 14e that is removed as the piston 14c moves is transferred to the piping 14b and the port.
It is quickly discharged to the outside through OUT2, the fluid chamber A between the valve parts 5b and 5c of the spool 5, and the port EXH2, and the piston 14c is driven to the upper stroke end.

Next, when the output shaft 7a of the electric motor 7 is swung or rotated by half a rotation and the side of the maximum diameter b of the cam 8 is positioned on the side of the main body block 2, the spool 5 is
Due to the biasing force of the cam follower 9, which follows the cam 8 and is displaced in the axial direction, the cam follower 9 is moved in the direction away from the control block 3, resulting in the state shown in FIGS. The port OUT1 is communicated with the EXH1 via the fluid chamber B.

Pressurized fluid flows into the fluid chamber 14e of the cylinder device 14 from a fluid pressure source (not shown) via the piping 14b, port OUT2, fluid chamber A, and port IN, and the piston rod 14f flows into the piston 14c. A thrust is generated in the direction of projecting the fluid chamber 14d to the outside, and the fluid chamber 14d
The fluid inside the fluid chamber 14d, which is opened to the outside through the port OUT1, the fluid chamber B, and the port EXH1, and is removed as the piston 14c moves, is quickly discharged to the outside.

In this way, in this embodiment, the rotational displacement of the output shaft 7a of the electric motor 7 is converted into a linear displacement via the cam 8 and the cam follower 9, and the spool 5 locked to the cam follower 9 is moved in the axial direction. Since the spool 5 is configured to be driven, even when the stroke of the spool 5 is large, the thrust required for driving the spool 5 does not become larger than necessary, as is the case when an electromagnet is used to drive the spool 5. The size of the electric motor 7 to be driven can be reduced.

Thereby, the overall dimensions of the electric switching valve 1 can be reduced.

Further, as shown in FIGS. 2, 4, and 7, at the end of the stroke of the spool 5 and in the middle of the stroke, the outer periphery of the minimum diameter a and the maximum diameter b of the cam 8 or the outer periphery of the cam ring shape Since these two points are in contact with the contact parts 9a and 9b of the U-shaped cam follower 9 at the same time, the position of the spool 5 is reliably maintained at the end of the stroke and in the middle of the process, and the reciprocating movement of the spool 5 is Even when the spool 5 is operated at high speed, problems such as the inertia of the spool 5 and the like causing instability in the stopping position at the end of the stroke shown in FIGS. 1 and 3 and generation of vibration can be reliably prevented. Ru.

Furthermore, in the above description of the operation, the output shaft 7a is rotated or oscillated by a half turn, but by appropriately adjusting the rotation angle and direction of the output shaft 7a, the rotation angle and direction of the output shaft 7a can be adjusted as shown in FIGS. The stopping operation of the spool 5 to a pressure position in the middle of the stroke end, the fine movement operation, etc. can be performed extremely easily compared to control using an electromagnet or the like.

For this reason, for example, the spool 5 is stopped at an intermediate position of the stroke, and the plurality of valve parts 5b, 5c, 5d
control to simultaneously close a plurality of ports OUT2, port IN, and port OUT1 to simultaneously prevent fluid supply and discharge to and from the fluid chambers 14d and 14e in the cylinder device 14, thereby fixing the piston 14c at an arbitrary position; The spool 5 is stopped in the middle of the process, and the ports OUT2, PORT IN, and OUT1 are
The opening degree of the fluid chamber 14 of the cylinder device 14 is adjusted.
Various controls such as controlling the moving speed of the piston 14c by adjusting the flow rate of the fluid supplied to and discharged from the piston 14c can be easily realized.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

Furthermore, in the embodiment described above, the main body block 2 and the operating space 3a of the control block 3 communicate with each other, but
Structurally, a seal structure is provided on the spool shaft 5a,
As shown in FIGS. 5 and 6, exhaust gas is prevented from flowing into the operating space 3a of the control block 3 by closing the main body block 2 and the control block 3 except for the portion through which the spool shaft 5a passes. A structure that does this can also be easily realized. Furthermore, in some cases, the spring 1
It is also possible to interpose 1b.

〔Effect of the invention〕

(1) an electric motor capable of controlling the rotation angle of an output shaft; a valve body that controls fluid through axial displacement; and an electric motor interposed between the output shaft of the electric motor and the valve body; a displacement converting means for directly converting rotational displacement of the output shaft into a linear displacement and transmitting the linear displacement to the valve body, the displacement converting means being locked to the output shaft, and having a constant diameter passing through the output shaft. The structure includes a cam and a cam follower that is locked to the valve body and is linearly displaced by always slidingly contacting and following the cam at two locations on the diameter including the output shaft. To realize miniaturization of an electric motor and an electric switching valve to which the electric motor is mounted, without making it necessary to increase the torque at the output shaft of the electric motor more than necessary even in the case of a spool or the like in which the axial movement distance of the valve body is large. Can be done.

In addition, the cam that is fixed to the output shaft of the electric motor and rotates, and the cam follower that converts the rotational displacement of this cam into linear displacement and transmits it to the valve body are always in contact at two points on the diameter including the output shaft. Because of its structure, by stopping or slightly moving the output shaft of the motor at any rotation angle, it is possible to stop the valve body at any position in its stroke, maintain the position, and even change the rotation angle of the output shaft. It is possible to perform proportional displacement of the valve body, and various controls can be easily realized.

Furthermore, the cam, which is fixed to the output shaft of the electric motor and rotates, and the cam follower, which converts the rotational displacement of this cam into linear displacement and transmits it to the valve body, are always in contact at two points on the diameter including the output shaft. Because of this structure, shearing force in a direction intersecting the displacement direction of the valve body and cam follower does not act on the cam follower or the valve body. Therefore, there is no need to insert an extra member between the cam follower and the valve body to avoid the generation of the shearing force, and the structure is simplified by reducing the number of parts, and the assembly work is also simplified. It becomes easier.

(2) As a result of (1) above, the space required for installing the electric switching valve is reduced, and the entire fluid pressure system in which the electric switching valve is incorporated can be downsized.

(3) As a result of (1) above, the performance of the electric switching valve is improved,
Marketability improves.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of an electric switching valve according to an embodiment of the present invention at one switching position;
The figure is a sectional view of the part indicated by the line - in Fig. 1, Fig. 3 is a sectional view showing the operation of the electric switching valve of this embodiment at another switching position, and Fig. 4 is a sectional view of the part indicated by the line - in Fig. 3. A cross-sectional view of the part indicated by
Fig. 5 is a sectional view of an embodiment that prevents exhaust gas from flowing into the operating space of the control block, Fig. 6 is a sectional view of the portion indicated by the line -, and Fig. 7 shows the shape of the ring of the cam in this embodiment. FIG. 1...Electric switching valve, 2...Main block, 3...
...Control block, 3a...Operating space, 4...Sleeve, 5...Spool (valve body), 5a...Spool shaft, 5b, 5c, 5d...Valve section, 6...O ring, 7...Electric motor , 7a... Output shaft, 7b... Cable, 8... Cam (displacement converting means), 9... Cam follower (displacement converting means), 9a, 9b... Contact portion, 10... Lid, 11a, 11b ...spring,
12... Lid body, 12a... Bush, 13... Spacer, 14... Cylinder device, 14a, 14b
...Piping, 14c...Piston, 14d, 14e
...Fluid chamber, 14f...Piston rod, 15...
…O-ring, IN…port, OUT1, OUT2
...Port, EXH1, EXH2...Port, A,
B...Fluid chamber, a...Minimum diameter of the cam, b...Maximum diameter of the cam, T...Sum of the minimum diameter and maximum diameter.

Claims (1)

[Claims] 1. An electric motor capable of controlling the rotation angle of an output shaft, a valve body that controls fluid by axial displacement, and an electric motor that is interposed between the output shaft of the electric motor and the valve body, and that and a displacement converter that directly converts rotational displacement of the shaft into a linear displacement and transmits the linear displacement to the valve body, and the displacement converter includes a cam having a constant diameter that is locked to the output shaft and passes through the output shaft. and a cam follower that is locked to the valve body and linearly displaced by always slidingly contacting and following the cam at two diametrical locations including the output shaft. .