JP2567565B2 - Electro-hydraulic servo valve and servo actuator with temperature compensation mechanism including the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-hydraulic servo valve and a servo actuator with a temperature compensation mechanism including the electro-hydraulic servo valve. Servo actuator with temperature compensation mechanism.

[0002]

2. Description of the Related Art Conventionally, a servo actuator using an electro-hydraulic servo valve has a large output power and a high response speed.
Widely used for large-scale numerical control machine tools. It is also used in the attitude control system of missiles, extreme work robots, etc., which are used in a wide range of temperature environments. This type of servo actuator has, for example, a valve body such as a spool, a valve body housing member such as a sleeve that houses the valve body slidably in a predetermined direction, and a drive mechanism that drives the valve body in a predetermined direction. An electrohydraulic servo valve in which a valve element in a neutral position is superposed on at least one port of a plurality of ports opened in a valve element housing member is used. In addition, the valve body and the port portion of the valve body housing member reduce the amount of hydraulic oil leakage, and for the reason that a dither signal is applied so as not to cause negative polymerization even when the valve body is slightly vibrated, There is one that uses normal polymerization with some allowance.

[0003]

However, in such a conventional servo actuator using the electrohydraulic servo valve, the valve body and the valve body accommodating member constituting the servo valve are reduced as the operating environment temperature decreases. There is a drawback that the sliding resistance with respect to each other and the resistance of the sliding portion of the actuator are significantly increased, and the responsiveness as a servo actuator is deteriorated.

In view of this, the present invention provides an electrohydraulic servo valve having a rapid response even when the temperature is lowered by reducing the amount of superposition of the valve body and the valve body housing member as the temperature is lowered. The first purpose. Further, the present invention provides an electrohydraulic servoactuator capable of improving the reaction speed of the actuator by reducing the amount of superposition of the electrohydraulic servovalve with a decrease in temperature and exhibiting high-speed responsiveness even when the temperature drops. The second purpose is to do so.

[0005]

To achieve the above object, the invention according to claim 1 is characterized in that a valve body, a valve body housing member for housing the valve body slidably in a predetermined direction, and a valve body are provided. A drive mechanism for driving in a predetermined direction, wherein the drive mechanism is an electrohydraulic servo valve in which a valve element in a neutral position is superposed on at least one port of a plurality of ports opened in a valve element storage member. A drive unit main body having a linear expansion coefficient substantially the same as that of the valve body storage member; and a valve body and a drive unit main body having a linear expansion coefficient larger than that of each member of the drive unit main body and extending in the predetermined direction. And a connecting member for connecting,
The polymerization amount of the valve body polymerized with respect to the at least one port is decreased with a decrease in temperature.
In the invention described above, the valve element is a spool that is positively polymerized with respect to the at least one port, and the drive mechanism is a rod-shaped connection in which one end is connected to the spool and the other end is connected to the drive unit main body. It is characterized by having a member.

According to a third aspect of the present invention, the first and second valve bodies, the pressure supply port and at least one output port are opened, and the first valve body is slidably housed in a predetermined direction. Second valve for accommodating the second valve element slidably in a predetermined direction by opening the valve element accommodation member, the input port communicating with any one of the output ports, and the drain port communicating with the tank side. An electro-hydraulic servo valve having a body accommodating member and a drive mechanism for driving the first and second valve bodies to be displaced in opposite directions in the predetermined direction, and to each port of the electro-hydraulic servo valve. Between a plurality of oil passages to be connected and a piston storage chamber connected to the output port, and between an actuator housing in which the electro-hydraulic servo valve is mounted and an actuator housing stored in the piston storage chamber. An actuator piston that defines a hydraulic chamber, the hydraulic oil supplied from the pressure supply port into the first valve body storage member by driving the first and second valve bodies, and the output port From the drain port to the reservoir tank side while the hydraulic oil supplied from the input port into the second valve body housing member is supplied from the drain port to the hydraulic chamber and the input port of the second valve body housing member. A servo actuator adapted to flow out, wherein the first valve element in the neutral position with respect to the pressure supply port is positively polymerized, and the second valve element in the neutral position with respect to the drain port is positively polymerized, and The drive mechanism of the electrohydraulic servo valve includes a drive unit main body having a linear expansion coefficient substantially the same as that of the valve body storage member, a linear expansion coefficient larger than each member of the drive unit main body, and the predetermined direction. A first and a second connecting member that extends and connects the valve body and the drive unit main body, and reduces the polymerization amount of the first and second valve bodies as the temperature decreases. It is characterized by having done.

In view of the difference in linear expansion coefficient between the connecting member and the fact that they have substantially the same linear expansion coefficient in claims 1 and 3, the linear expansion between each member of the drive unit main body and the valve body accommodating member is considered. This means that the difference in the coefficients is so small that it needs almost no consideration.

[0008]

According to the invention of claim 1, the valve body housing member and the drive unit main body have substantially the same linear expansion coefficient, and the connecting member connecting the valve body and the drive unit main body has a larger linear expansion coefficient. . Therefore, the amount of superposition of the valve body and the port provided in the valve body housing member can be reduced as the temperature decreases.

According to the second aspect of the present invention, the spool and the drive portion main body are connected by the rod-shaped connecting member, and the spool and the port provided in the valve body housing member are positively superposed. Therefore, while simplifying the structure of the drive mechanism, the positive polymerization amount of the spool and the port can be reduced as the temperature decreases, and the leakage of hydraulic oil can be prevented to the minimum.

According to the third aspect of the invention, the electrohydraulic servo valve is used in which the valve body and the port provided in the valve body housing member are positively polymerized and the amount of polymerization is reduced as the temperature decreases. Therefore, it is possible to prevent the response deterioration of the actuator due to the increase of the sliding resistance.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 are views showing an embodiment of an electrohydraulic servo valve and a servo actuator with a temperature compensation mechanism including the same according to the present invention. FIG. 1 is a configuration diagram of an electrohydraulic servo valve portion, and FIG. FIG. 3 is a partially enlarged view thereof, FIG. 3 is an overall mechanical configuration diagram of one embodiment, and FIG. 4 is an overall configuration diagram of one embodiment.

First, the structure will be described. 1 to 3, reference numeral 100 denotes an electrohydraulic servo valve and a servo actuator with a temperature compensation mechanism including the electrohydraulic servo valve. The servo actuator 100 includes an actuator housing 1. The actuator housing 1 includes sleeve housings 2 and 3, an oil passage 4 for hydraulic oil,
5, 6, 7, and 8 are provided. The sleeve storage portions 2 and 3 are cylindrical holes with a bottom provided in the actuator housing 1, and the sleeve 10 (first valve body storage member) and the sleeve 11 (second valve body storage member) are stored in these holes. It is supposed to be done. The sleeves 10 and 11 have inner peripheral wall surface portions 10a and 11a inside. Also, the sleeve 10 has a pressure supply port 10b and an output port 10 which are open from the outer peripheral surface to the inner peripheral wall surface portion 10a.
Similarly, the sleeve 11 has an input port 11b and a drain port 11c which are open from the outer peripheral surface to the inner peripheral wall surface portion 11a. The oil passage 4 is connected to the pressure supply port 10b, the oil passage 5 is connected to the output port 10c, the oil passage 6 is connected to the output port 10d, the oil passage 7 is connected to the input port 11b, and the oil passage 8 is connected to the drain port 11c. Has been done. Also, the sleeves 10 and 11
Is adapted to slidably accommodate the spool 12 (first valve body) and the spool 13 (second valve body). The spools 12 and 13 are the inner peripheral wall surface portion 10 of the sleeves 10 and 11.
a, 11a, and small diameter portions 12a, 13a, and land portions 12b, 12 having a diameter larger than the small diameter portions 12a, 13a and slightly smaller than the inner peripheral wall surface portions 10a, 11a.
c, 13b, 13c, a valve chamber portion 12d is formed between the small diameter portion 12a and the inner peripheral wall surface portion 10a, and a valve chamber portion 13d is formed between the small diameter portion 13a and the inner peripheral wall surface portion 11a. It is supposed to do. The spools 12 and 13 are
The opening of the output port 10d of the sleeve 10 or the drain port 11c of the sleeve 11 can be changed by moving the lands 12c and 13c in the axial direction of the inner peripheral wall surface. The hydraulic oil is supplied from a supply device (not shown) (in the direction of arrow A in FIG. 1) and is supplied to the hydraulic chamber 55 via the oil passage 4, the pressure supply port 10b, the valve chamber portion 12d, and the output port 10c. The hydraulic oil in the hydraulic chamber 54 is the oil passage 6, the oil passage 7, the input port 11 b, the valve chamber portion 13.
It is configured to be discharged to the reservoir tank 9 through d, the drain port 11c, and the oil passage 8 (direction of arrow B in FIG. 1).

As shown in FIG. 2, when the spools 12 and 13 are in the neutral position, the land portion 12c of the spool 12 and the output port 10d of the sleeve 10 are positively overlapped (overlapped) with the overlapping amount D1, and the spools Land part 1 of 13
3c and the drain port 11c of the sleeve 11 are configured to positively polymerize with a polymerization amount D2. The amount of this positive polymerization D
1 and D2 are set to be larger than the sum of the amount of decrease in the polymerization amount due to the temperature decrease, which will be described later, and the amount of minute vibration due to a dither signal or the like (set as necessary).

On the other hand, the spool 1 is attached to the spools 12 and 13.
4 and 15 (connecting members) are screwed together, and both screws
The pools 12 and 13 have male screw portions at both ends.
Rods 14 and 15 and locking nuts 16, 17 and 19,
Connected to both ends of the armature 18 via
There is. The armature 18 is a strobe for rods 14 and 15.
Angle range of about 0.1 mm to 0.3 mm
Centering spring so that it swings around
Is attached to the base plate 22 via the ring 21,
Electromagnets 23 and 24 are attached to the base plate 22.
You. These armature 18, nuts 19, 20, and sen
The terring spring 21 and the base plate 22 are the main drive unit.
The body 31 is formed, and the rods 14 and 15 and the electromagnet 23 are
A drive mechanism 30 is configured with 24. The armor
The Chua 18 is commonly made of a ferromagnetic material such as iron.
Both ends are located on the axes of the electromagnets 23 and 24.
Swelling. The centering spring 21 has a T-shape.
It has a shape, and due to its elasticity, the spool 12, 13
Is always kept neutral. Constituting the drive unit body 31
Armature 18, nuts 19, 20, centering
The spring 21 and the base plate 22 are the spools 12 and 1
3 and the sleeves 10 and 11 have substantially the same linear expansion coefficient.
The rods 14 and 15 have a larger linear expansion than these.
It is formed of a material having a coefficient. Specifically sp
Base 12, 13, sleeves 10, 11 and drive unit main body
31 is a steel-based material such as SUS304
Tenless steel (coefficient of linear expansion of about 11.7 × 10^-6/ ℃), nitrogen
Chemical steel (coefficient of linear expansion 12.4 × 10 ^-6/ ° C) or S4
Steel materials such as 5C (coefficient of linear expansion of about 11.7 × 10^-6/ ° C)
For example, for the rods 14 and 15 that are the connecting members,
Aluminum such as 2024 (coefficient of linear expansion of about 23.2 × 1
0^-6/ ° C) or its alloys (for example, duralumin)
Is preferred. Of course, it corresponds to the swing of the armature 18.
It is a material that can bend slightly and is
Any material having a sufficiently large linear expansion coefficient may be used. B
The material of the pads 14 and 15 is not particularly limited. In this example
Are sleeves 10, 11, spools 12, 13 nitrided steel,
The base plate 22 or its protruding portion 22a is
Ring spring 21 is phosphor bronze and armature 18 is soft
Made from iron, rods 14 and 15 made from stainless steel
Is made.

Further, the actuator housing 1 has large and small cylinders 50 and 51 (piston accommodating portions) each having a circular cross section, and a large piston 52 (actuator piston) and a small piston 53 (actuator piston) are provided therein. And are slidably stored. The oil passage 6 is connected to the cylinder portion 50 and the oil passage 5 is connected to the cylinder portion 51 so that hydraulic chambers 54 and 55 are defined, respectively. Supply pressure is constantly applied to the cylinder chamber 55. The pressure receiving area of the cylinder chamber 54 is twice as large as the pressure receiving area of the cylinder chamber 55. By controlling the flow rate of the inflow and outflow of the cylinder chamber 54 by the two sets of sleeves 10, 11, and spools 12, 13, 52, 5
3 can be moved in the axial direction of the cylinder parts 50, 51. The pistons 52 and 53 are respectively connected to connecting rods 56 and 57 each having a spherical shape at both ends, and the other ends of the connecting rods 56 and 57 are swingably connected to both arm portions of a swing arm 58, respectively. Has been done. The swing arm 58 swings the output shaft 59 to control an object (not shown).

In FIG. 4, reference numeral 70 designates a signal generating means for outputting a target value signal corresponding to the target operating state of the output shaft 59. Reference numeral 71 is a detection means for detecting the rotation angle of the output shaft 59 and outputting an electric signal corresponding to the detected angle, which is, for example, a potentiometer or the like. Numeral 72 is an addition means for outputting the deviation between the target value signal from the signal generation means 70 and the feedback signal from the detection means 71 to the amplification means 73. The amplification means 73 amplifies the output from the addition means 72 to excite the electromagnets 23 and 24.

Next, the operation will be described. First, when the exciting currents of the electromagnets 23 and 24 are equal, the spools 12 and 1
The centering spring 21 holds the rod 3 and the rods 14 and 15 in the neutral position. At this time, the spool 12 closes the output port 10d at the land portion 12c, and the spool 13 closes the drain port 11 at the land portion 13c.
Since c is closed, the hydraulic oil is supplied to the hydraulic chamber 55 through the oil passage 5, but the hydraulic oil does not enter or leave the hydraulic chamber 54. Therefore, the small piston 53 that receives the hydraulic pressure tries to swing the swing arm 58, but the large piston 5
2 cannot be pushed down and the swing arm 58 does not rotate the output shaft 59. Therefore, in this case, the servo actuator 100 is almost stationary.

Next, the exciting current of the electromagnet 23 is changed to the electromagnet 24.
When it becomes larger than the exciting current of, the left end of the armature 18 made of a ferromagnetic material is magnetized by the electromagnet 23,
It is drawn in the direction of arrow P in FIG. Armature 18
When the left end of the armature is pulled in the P direction, the armature 1 whose center is supported by the centering spring 21
The right end of 8 moves in the S direction. At this time, the rod 14 screwed to the armature 18 and the spool 12 screwed to the rod 14 move in the P direction, but the output port 10d of the sleeve 10 remains closed.
However, since the right end of the armature 18 moves in the S direction, the rod 15 screwed to the armature 18 and the spool 13 screwed to this move in the S direction, and the drain port 11c opens. On the other hand, since the supply pressure is constantly applied to the cylinder chamber 55, the working oil stored in the hydraulic chamber 54 of the servo actuator 100 passes through the oil passages 6 and 7, the drain port 11c and the oil passage 8 and is stored in the reservoir tank 9. Discharged to the side. Therefore, the swing arm 58 rotates the output shaft 59 counterclockwise in FIG.

Next, the exciting current of the electromagnet 24 is changed to the electromagnet 23.
When it becomes larger than the exciting current of the armature 18, the magnetic force of the electromagnet 24 draws the right end of the armature 18 in the R direction and moves the left end of the armature 18 in the Q direction. At this time, the rod 1 screwed into the right end of the armature 18
Since 5 and the spool 11 screwed to it move in the R direction, the drain port 11c of the sleeve 11 is closed. Furthermore, the left end of the armature 18 moves in the Q direction, so that the rod 14 and the spool 1 screwed to the rod 14 are moved.
2 moves in the Q direction, and the output port 10d opens. Therefore, the hydraulic oil supplied from the pressure supply port 10b to the valve chamber portion 12d is supplied to the hydraulic chamber 55 from the output port 10c via the oil passage 5 and also from the output port 10d via the oil passage 6 to the hydraulic chamber 54. Will also be supplied. Then, due to the difference in pressure receiving area between the small piston 53 and the large piston 52,
The swing arm 58 swings so as to rotate the output shaft 59 clockwise in FIG. Thus, the electromagnets 23, 24
By changing the excitation state of the servo actuator 1
00 is controlled.

On the other hand, when the operating environment temperature of the servo actuator 100 decreases, the spools 12 and 13, the sleeves 10 and 11 and the drive unit main body 31 (hereinafter, referred to as all spools 12 and 13) have substantially the same line. Since it has an expansion coefficient, it shrinks uniformly as the ambient temperature decreases, but the rods 14 and 15 connecting the spools 12 and 13 and the drive unit main body 31 are larger than the spools 12 and 13 and the like. Spool 1 because it has an expansion coefficient
Contracted more than 2, 13, etc., resulting in rod 1
Reference numerals 4 and 15 move relative to the sleeves 10 and 11 in the Q direction and the S direction, respectively. Therefore, the output port 10d of the sleeve 10 and the land portion 12 of the spool 12 are
c polymerization amount D1, sleeve 11 drain port 11c
And the amount D2 of superposition between the land portion 13c of the spool 13 and the land portion 13c of the spool 13 decreases. Therefore, as the environmental temperature decreases, the spool 12 and the sleeve 10 and the spool 13 and the sleeve 1
Although the sliding resistance of No. 1 increases, the required moving amount (stroke) of the spools 12 and 13 at the time of opening / closing the port can be decreased by reducing the overlapping amounts D1 and D2, and the deterioration of responsiveness can be compensated.

As described above, in this embodiment, among the constituent members of the electrohydraulic servo valve, the spools 12 and 13, the sleeves 10 and 11 and the drive unit main body (the armature 18,
The centering spring 21 and the base plate 22) are made of a material having substantially the same linear expansion coefficient.
Since a rod having a larger linear expansion coefficient than these is used for the rod that connects the drive unit main body with the drive unit main body, the spool 1
End of 2 and 13 land parts 12c and 13c and sleeve 1
The amount of polymerization of the output ports 10d of 0 and 11 with the ends of the drain port 11c can be reduced with a decrease in temperature, and the spools 12 and 13 and the sleeve 1 with the decrease in temperature can be reduced.
It is possible to mitigate the deterioration of responsiveness due to the increase of the sliding resistance with respect to 0 and 11.

Further, the overlap amount D1 of the spool 12 and the output port 10d and the overlap amount D2 of the spool 13 and the drain port 11c are set to the rods 14 and 15 which are rod-shaped connecting members.
The driving mechanism 30 reduces the temperature with decreasing temperature.
It is possible to minimize the leakage of hydraulic oil while simplifying the configuration of. Further, since the spool 12 and the output port 10d, and the spool 13 and the drain port 11c are positively polymerized in the electrohydraulic servo actuator, the electrohydraulic servovalve in which the amount of polymerization is reduced as the temperature is reduced is used. Large piston 52 and cylinder 5 associated with
The increase in sliding resistance between 0 and the small piston 53 and the cylinder 51 is mitigated by improving the responsiveness of the electrohydraulic servo valve,
It is possible to provide a safe and reliable servo actuator which can alleviate the response deterioration of the servo actuator at a low temperature and does not malfunction even at a low temperature.

[0023]

According to the first aspect of the present invention, materials having substantially the same linear expansion coefficient are used for the valve body housing member and the drive unit main body, and the connecting member for connecting the valve body and the drive unit main body is used. Since a material having a linear expansion coefficient larger than those is used, the amount of polymerization between the valve body and the port provided in the valve body housing member can be reduced as the temperature decreases, and the sliding resistance accompanying the temperature decrease can be reduced. It is possible to mitigate the deterioration of the responsiveness due to the increase of. As a result, it is possible to provide an electro-hydraulic servo valve having a good response even at low temperatures.

According to the second aspect of the present invention, the spool and the drive unit main body are connected by a rod-shaped connecting member, and
Since the spool and the port of the valve body storage member are positively polymerized, the amount of polymerization of the spool and the port can be reduced as the temperature decreases, and the leakage of hydraulic oil can be minimized. Therefore, it is possible to provide the electro-hydraulic servo valve having excellent responsiveness and excellent stability even at a low temperature.

According to the third aspect of the invention, since the valve body and the port provided in the valve body accommodating member are positively polymerized, and the electrohydraulic servo valve whose amount of polymerization is reduced as the temperature is lowered is used. It is possible to provide an electro-hydraulic servo actuator having excellent responsiveness even at low temperatures and excellent stability.

[Brief description of drawings]

FIG. 1 is a front sectional view of an electrohydraulic servo valve portion showing an embodiment of an electrohydraulic servo valve and a servo actuator with a temperature compensation mechanism including the electrohydraulic servo valve according to the present invention.

FIG. 2 is an enlarged view of the overlapping portion of the valve body and the port.

FIG. 3 is a cross-sectional view showing a configuration of a servo actuator according to an embodiment.

FIG. 4 is an overall configuration diagram of an embodiment.

[Explanation of symbols]

 1 Actuator Housing 4, 5, 6, 7, 8 Oil Path 9 Reservoir Tank 10 Sleeve (First Valve Body Storage Member) 10b Pressure Supply Port 10c, 10d Output Port 11 Sleeve (Second Valve Body Storage Member) 11b Input Port 11c Drain port 12 Spool (first valve body) 13 Spool (second valve body) 14, 15 Rod (connecting member) 18 Armature 21 Centering spring 22 Base plate 23, 24 Electromagnet 30 Drive mechanism 31 Drive unit body 50 , 51 Cylinder part (piston housing part) 52 Large piston (actuator piston) 53 Small piston (actuator piston) 100 Servo actuator

Claims (3)

(57) [Claims] 1. A valve body, a valve body housing member for housing the valve body slidably in a predetermined direction, and a drive mechanism for driving the valve body in the predetermined direction, the opening being formed in the valve body housing member. An electrohydraulic servovalve in which a valve element in a neutral position overlaps at least one of the plurality of ports, wherein the drive mechanism has a drive unit main body having a linear expansion coefficient substantially the same as that of the valve element storage member. A connecting member that has a linear expansion coefficient larger than that of each member of the drive unit main body and that extends in the predetermined direction and connects the valve body and the drive unit main body, and is superposed on the at least one port. An electrohydraulic servo valve characterized in that the amount of polymerization of the valve body is reduced with a decrease in temperature. 2. A rod-shaped connection in which the valve element is a spool positively overlapped with the at least one port, and the drive mechanism is connected to the spool at one end and to the drive unit main body at the other end. The electrohydraulic servo valve according to claim 1, further comprising a member. 3. A first valve body and a second valve body, and a first valve body accommodating member for accommodating the first valve body slidably in a predetermined direction by opening a pressure supply port and at least one output port. A second valve body storage member for storing an input port communicating with any one of the output ports and a drain port communicating with the tank side for storing the second valve body slidably in a predetermined direction; An electro-hydraulic servo valve having a drive mechanism for driving the first and second valve bodies to be displaced in opposite directions in the predetermined direction, and a plurality of oil passages connected to respective ports of the electro-hydraulic servo valve. And a piston accommodating chamber connected to the output port is formed, and an hydraulic chamber is defined between the actuator housing in which the electro-hydraulic servo valve is mounted and the actuator housing accommodated in the piston accommodating chamber. And a hydraulic fluid supplied from the pressure supply port into the first valve body accommodating member by driving the first and second valve bodies, and from the output port to the hydraulic chamber and the hydraulic chamber. A servo which supplies hydraulic fluid to the input port of the second valve body storage member and also causes hydraulic fluid supplied from the input port into the second valve body storage member to flow out from the drain port to the reservoir tank side. An actuator, wherein the first valve body in the neutral position with respect to the pressure supply port is positively polymerized, and the second valve body in the neutral position with respect to the drain port is positively polymerized, and the electrohydraulic servo valve is driven. The mechanism includes a drive unit main body having substantially the same linear expansion coefficient as that of the valve body storage member, a linear expansion coefficient larger than that of each member of the drive unit main body, and extending in the predetermined direction to drive the valve body. A first and a second connecting member for connecting the moving part body to each other, and the polymerization amount of the first and second valve bodies is reduced with a decrease in temperature. Servo actuator with temperature compensation mechanism.