JP3494858B2 - Hydraulic servo device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic servo device for converting a rotational displacement of a small torque into a linear displacement of a large load, and is particularly suitable for use in drive control of a scoop tube which is a speed change mechanism in a variable speed fluid coupling. Hydraulic servo device.

[0002]

2. Description of the Related Art FIG. 11 shows a structure of a drive unit of a water supply device used for supplying water to a large capacity boiler, for example, the rotation of an input shaft 121 being a large gear 122 and a small gear 124.
Is transmitted to the drive shaft 123 via the fluid coupling C, is further transmitted to the driven shaft 125 via the fluid coupling C, and is further transmitted to the output shaft 132 via the large gear 131 and the small gear 133. To be done. The fluid coupling C includes an impeller 126 and an impeller casing 128 attached to the drive shaft 123.
And a runner 127 attached to the driven shaft 125. When the working oil is introduced into the impeller casing 128, the viscosity of the working oil causes the two to work together to transmit the rotation.

A scoop tube 130 for adjusting the amount of hydraulic oil is arranged in the hydraulic oil chamber, and the transmission torque of the fluid coupling is controlled by taking it in and out. Such a fluid coupling C has a relatively simple structure,
The rotation speed on the load side can be continuously changed from the minimum rotation speed to the maximum rotation speed.

The scoop tube needs to be accurately positioned against the force received from the hydraulic oil, and therefore, as a drive device thereof, for example, Japanese Patent Laid-Open No. 7-20849.
A hydraulic servo device as shown in No. 9 is used which amplifies and transmits a displacement of a small force by an electric actuator.
In this, a piston is slidably provided on a pilot shaft arranged in a cylinder, an oil passage is formed on the surface of the pilot shaft and inside the piston, and rotation of the pilot shaft is converted into displacement of the piston for output. With such a driving device, for example, feedback control is performed based on a signal from a displacement sensor provided at a predetermined position to control the position of the scoop tube.

[0005]

In the hydraulic servo system as described above, it is necessary to reduce the size in view of the overall balance, and for that purpose, it is necessary to reduce the diameter of the pilot shaft. However, if the pilot shaft diameter is made smaller, the width of the groove-shaped oil passage on the surface becomes smaller, and if the rotation of the pilot shaft is made faster, as shown in FIG. It may become Therefore, there is a problem that the control response of the hydraulic servo device is limited.

It is an object of the present invention to provide a hydraulic servo system which is small in size and has a sufficient control response even if the pilot shaft has a small diameter.

[0007]

According to a first aspect of the present invention, there is provided a pilot shaft and a piston arranged in a cylinder, and the pilot shaft is rotated to form a conduction path formed on a surface of the pilot shaft. In the hydraulic servo device that drives the piston in the axial direction by communicating with the oil passage formed in the piston, the piston and the pilot shaft each have the oil passage for driving the piston in the same direction. At least two pairs are provided, and the plurality of
The rotation angle at which the communication path and the oil path of the
The hydraulic servo device is characterized by being provided as described above. Thus, without increasing the diameter or width of each oil passage or conduction passage, the communication angle can be widened to prevent "wheel derailment" from occurring, and higher control response can be obtained.

[0008] The invention described in 請 Motomeko 2, the conducting path,
The hydraulic servo device according to claim 1, wherein the hydraulic servo device is provided in a non-linear manner with respect to a rotation angle of the pilot shaft.

[0009] Before Kiyuro also oil discharge passage leading to the oil supply passage and a drain connected to the pressure hydraulic fluid is arranged independently of one another
May be

[0010] According to a third aspect of the invention, the space pre-Symbol cylinder communicates via the conductive path of the first space, the space of the first with a pressurized oil hole by the piston, or blocks 3. The hydraulic servo device according to claim 1, wherein the hydraulic servo device is divided into a second space, and an air vent pipe that opens to an external space is provided at an upper portion of the second space. is there. Thereby, highly compressible air can be removed from the second space in which air does not easily escape, and high responsiveness can be maintained.

[0011] be provided with the orifice before Symbol air vent pipe
Good . In addition, even if the check valve provided in the air vent pipe
Yes .

[0012] According to a fourth aspect of the invention, the space before Symbol cylinder communicates via the conductive path of the first space, the space of the first with a pressurized oil hole by the piston, or blocks 3. The hydraulic servo device according to claim 1, wherein the hydraulic servo device is divided into a second space, and a recess for accumulating particles is formed in a lower portion of the first and / or the second space. As a result, the particles gather in the recess, so that the sliding portion between the piston and the cylinder is prevented from being caught, and stable operation is performed.

[0013] In order to discharge the reservoir was particles before Symbol recess
May be provided with a discharge hole.

According to a fifth aspect of the present invention, there is provided a pilot shaft and a piston arranged in the cylinder, and the pilot shaft is rotated to form a conduction path formed on the surface of the pilot shaft in the piston. In the hydraulic servo device that drives the piston in the axial direction by communicating with the oil passage, the space in the cylinder is formed by a first space having a pressure oil hole by the piston, and the first space and the communication passage. It is partitioned into a second space that is communicated with or cut off via the first space, and the first space is outside the cylinder on the first space side .
The hydraulic servo device is characterized in that an oil reservoir is formed to cover a piston sliding hole formed in a side wall on the space side .

[0015] comprising a sheet disposed pilot shaft within cylinder and the piston, the surface which is formed on the conductive passages is rotated by said pilot shaft the pilot shaft is communicated with the oil passage formed in the piston the In the hydraulic servo device that drives the piston in the axial direction, one end surface of the piston may be provided with an engaging portion that engages with a drawing tool for drawing the piston. This facilitates the maintenance of the piston and the cylinder, and the maintenance and replacement of the driven member attached to the piston.

According to a sixth aspect of the present invention, the position control is performed by the impeller and the impeller casing attached to the drive shaft, the runner attached to the driven shaft, and the hydraulic servo device according to any one of the first to fifth aspects. And a scoop tube that is formed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An example in which a hydraulic servo device according to an embodiment of the present invention is used as a drive device for a scoop tube of a fluid coupling shown in FIG. 11 will be described below with reference to the drawings. The hydraulic servo device shown in FIG. 1 includes a cylinder 10 which is a pressure vessel.
A pilot drive device 12 provided on the base end side of the cylinder 10; a pilot shaft 14 protruding from the pilot drive device 12 into the cylinder 10;
And a piston 16 slidably arranged in the space between the pilot shaft 14 and the rotation thereof. The piston 16 has a large diameter portion 18 on the base end side and a small diameter portion 20 on the tip end side.
The small-diameter portion 20 protrudes from the sliding hole 24 of the side wall 22 of the cylinder 10 to the outside, and the tip of the small-diameter portion 20 is provided with a mounting portion 26 for mounting a scoop tube which is a driven member.

The piston 16 divides the space inside the cylinder 10 into a first space 28 outside the small diameter portion 20 and a second space 30 on the large diameter portion 18 side. A pressure oil passage 32 communicating with the first space 28 is formed on the tip end side of the cylinder 10, and a convex portion 34 serving as a stopper is formed on the inner surface of the cylinder 10 to regulate the stop position of the piston 16. ,
The first space 28 connected to the pressure oil passage 32 is ensured even at the most advanced position.

A center hole 36 for inserting the pilot shaft 14 into the small diameter portion 20 and an oil supply passage 38 extending in the radial direction from the first space 28 and opening to the center hole 36 are provided with respect to the center as shown in FIG. Two are provided at substantially symmetrical positions. Further, an oil discharge passage 40 is formed at a position symmetrical with respect to the oil supply passage 38 in a cross section including an axis line, and the oil discharge passage 40 is opened at the attachment portion 26. Both the oil discharge passage 40 and the center hole 36 are connected to an external drain.

On the other hand, on the surface of the pilot shaft 14, there is provided a groove-shaped conduction path 42 for communicating the oil supply path 38 and the second space 30 with respect to the center, as shown in FIG. Two are provided at substantially symmetrical positions. This conduction path 4
2 is formed in a spiral shape so as to extend around the pilot shaft 14 almost half over the length corresponding to the stroke of the piston 16. In this example, the diameters of the oil supply passage 38 and the oil discharge passage 40 are set to be equal to the width of the conduction passage 42.

The pressure receiving surface of the piston 16 in the first space 28 is the difference between the cross section of the large diameter portion 18 and the cross section of the small diameter portion 20, but the pressure receiving surface in the second space 30 is the large diameter portion 18. Is a portion obtained by subtracting the pilot shaft 14 from the cross section, and the pressure receiving surface of the second space 30 is larger. Therefore, when the conduction path 42 connects the oil supply path 38 and the second space 30 and the same hydraulic oil pressure is applied to both the first space 28 and the second space 30, the piston 16 moves toward the tip side. Moving. Further, when the fluid passage 42 connects the oil discharge passage 40 and the second space 30 and hydraulic oil pressure is applied only to the first space 28, the piston 16 moves to the base end side.

The conduction path 42 in this example is formed non-linearly with respect to the angle as shown in FIG. 4, and as a result, the output (piston 1) with respect to the input (rotation angle) is eventually obtained.
6 stroke) is maintained. Large diameter part 18
Is formed to be hollow so that the conduction path 42 is not covered by the piston 16 even when the piston 16 moves to the most proximal side.

In this example, the rotation angle of the pilot shaft 14 at which the first oil supply passage 38 and the first oil discharge passage 40 and the second oil supply passage 38 and the second oil discharge passage 40 overlap each other is as shown in FIG. , The angle θ corresponding to the width of the oil passages 38, 40
There is a deviation α that does not exceed As a result, compared with the case where only one oil supply passage 38 and one oil discharge passage 40 are provided, the overlapping angular range becomes large (2θ + α), and it becomes difficult for the situation in which both overlaps are lost and operation becomes impossible.

The operation of the hydraulic servo device having the above structure will be described. When the pilot shaft 14 is rotated in the arrow direction from the state in which the conduction path 42 shown in FIG. 2 (a) is not in communication with the oil supply passage 38 or the oil discharge passage 40, as shown in FIG. 42 starts to communicate with the oil supply passage 38. As a result, the hydraulic oil pressure in the first space 28 is transmitted to the second space 30 via the oil supply passage 38 and the conduction passage 42, and the piston 1
The piston 16 is pushed toward the tip end side due to the pressure receiving area difference of 6.
Since the conduction path 42 is inclined with respect to the ridgeline of the pilot shaft 14, when the piston 16 moves toward the tip side, the conduction path 4
2 and the oil supply passage 38 return to the original positional relationship where they do not communicate as shown in FIG.

Further, when the pilot shaft 14 is rotated to bring the positional relationship shown in FIG. 2 (b), the piston 16 moves in the same manner. By continuously repeating this while detecting the axial position of the piston 16 and performing feedback control, the piston 16 can be placed at an arbitrary position in the axial direction.

Here, when the load is large, etc., FIG.
If the piston 16 does not move or the movement amount is small even in the state of (b), a signal is further output from the control device to the pilot drive device 12 and the pilot shaft 14 is rotated in the direction of the arrow, as shown in FIG. Reach the state of. In this state, since the hydraulic oil flows in from the two conduction paths 42, the force for driving the piston 16 is also increased and the responsiveness is improved. If the pilot drive 12
Even if a rotation signal is output to the oil supply path 38, since the rotation angle range in which the oil supply passage 38 and the conduction passage 42 communicate with each other is wide, it is difficult to "detach."

Next, when moving the piston 16 toward the base end side in the axial direction, the pilot shaft 14 is rotated in the direction opposite to that shown in FIG. 2B from the state shown in FIG. 2A. Then, the conduction path 42 starts to communicate with the oil discharge path 40, and the second space 30 has the same low pressure as the drain. As a result, the pressure from the hydraulic oil in the first space 28 causes the piston 16 to move to the base end side of the conduction path 42 until the oil discharge path 40 returns to the state shown in FIG. 2A. By repeating this while performing feedback control, the position of the piston 16 is controlled.
Since the second oil discharge passage 40 having the same positional relationship as that of the oil supply passage 38 is provided for the first oil discharge passage 40,
The functions of improving the responsiveness and preventing the wheel loss are maintained in the same manner as the forward movement.

FIG. 6 shows another embodiment of the present invention, in which an air bleeding pipe 44 is provided in the upper portion of the second space 30 of the cylinder 10 on the proximal end side. The air bleeding pipe 44 has an appropriate space (atmospheric pressure) through the orifice 46.
It is open to. In this embodiment, the pressure oil passage 3
The air contained in the hydraulic oil flowing in from 2 and accumulated in the second space 30 is discharged from the air bleeding pipe 44, so that the adverse effect of such air on the response of the hydraulic servo device can be suppressed. You can Further, the orifice 46 having the fine holes allows air to be discharged while maintaining the pressure in the second space 30.

FIG. 7 shows still another embodiment of the present invention, which is an improvement of the embodiment of FIG. An air vent pipe 44 connected to the atmosphere via an orifice 46 is provided above the cylinder 10, and an oil sump 48 is formed outside the tip end side of the cylinder 10 so as to cover the sliding hole 24 of the side wall 22 of the cylinder 10. Has been done. The oil sump 48 is formed by members such as a bottom plate 50 and a wall 52 attached to the side wall 22 of the cylinder 10.
A hole for inserting a driven member or the like is formed in 2 as required. The height of the oil sump is preferably equal to or higher than the connection position of the air vent pipe 44.

In the embodiment shown in FIG. 6, the air vent pipe 44
Is connected to the atmosphere through the orifice 46,
In the state where the device is stopped and the pressure is not applied to the second space 30, due to the pressure of the head of the second space 30,
The hydraulic oil oozes out from the gap between the sliding hole and the small diameter portion 20 of the piston 16, and the air flows in as much as that amount, resulting in unstable operation and reduced responsiveness at the next start. On the other hand, in the embodiment of FIG. 7, an oil sump is formed in the space outside the sliding hole to prevent the hydraulic oil from seeping out between the sliding hole and the small-diameter portion 20 for stable operation. Can be secured.

FIG. 8 is also an improvement of the embodiment of FIG. 6, in which the check valve 54 is provided in the air vent pipe 44 in addition to the orifice 46. The check valve 54 prevents air and the like from flowing into the second space 30 from the air bleeding pipe 44 when the operation of the device is stopped. Instead of the check valve, an on-off valve that can be operated remotely or automatically may be used so that it can be opened only when necessary.

FIG. 9 shows still another embodiment of the present invention. The cylinder 10 of this embodiment includes the piston 1 in the first space 28 and the second space 30.
Recesses 56 for temporarily containing particles generated by the sliding of the cylinder 6 and the cylinder 10 are formed at the ends of the cylinder 10 on the front end side and the base end side, respectively. In this example, a discharge hole 58 for discharging the particles P accumulated at the bottom of each recess 56 is provided, and this is closed by a pressure resistant plug 60. In this embodiment, the particles P generated along with the sliding are scraped by the recesses 56 on the bottom surface and accumulate there, so that the probability of remaining in the sliding portions is reduced, and therefore,
Occurrence of biting in the sliding portion is also reduced. The particles P accumulated to some extent are discharged by opening the plug 60 and washing with hydraulic oil or the like when the apparatus is not used.

FIG. 10 shows another embodiment of the present invention for the convenience of maintenance of the hydraulic servo device. That is, the large diameter portion 18 of the piston 16
A threaded hole 64 is formed on the end face of the screw hole, which is screwed into a long bolt 62, which is a pull-out tool for pulling the screw. In this embodiment, after draining the hydraulic oil from the inside of the cylinder 10, the side wall 22 on the base end side of the cylinder 10 is removed, the pilot shaft 14 is pulled out, and then the long bolt 62 is screwed into the screw hole 64.
And the piston 16 is pulled out by the bolt 62. Accordingly, the piston 16 can be taken out and the driven member and the like attached to the cylinder 10 and the piston 16 can be easily maintained without removing the cylinder 10 itself.

[0034]

As described above, according to the hydraulic servo system of the present invention, the diameter of the individual oil passages and the connecting passages and the width of the passages are not increased, and the communication angle is widened to "derail". Therefore, it is possible to provide a hydraulic servo device which is small in size and can obtain a sufficient control responsiveness.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a hydraulic servo device according to an embodiment of the present invention.

2A is a sectional view showing an engagement between an oil passage and a conduction passage at a certain rotation position in FIG. 1, and FIG. 2B is a sectional view showing an engagement between the oil passage and the conduction passage at another rotation position. .

3A is a cross-sectional view showing an engagement between an oil passage and a conduction passage at another rotation position in FIG. 1, and FIG. 3B is a cross-sectional view showing an engagement between an oil passage and a conduction passage of a conventional hydraulic servo device. Is.

FIG. 4 is a development view of a conduction path.

FIG. 5 is a graph showing rotation angles at which the first pair and the second pair of the oil passage and the communication passage communicate with each other.

FIG. 6 is a sectional view of a second embodiment of the present invention.

FIG. 7 is a sectional view of a third embodiment of the present invention.

FIG. 8 is a sectional view of a fourth embodiment of the present invention.

FIG. 9 is a sectional view of a fifth embodiment of the present invention.

FIG. 10 is a sectional view of a sixth embodiment of the present invention.

FIG. 11 is a sectional view of a fluid coupling in which the hydraulic servo device according to the present invention is used.

[Explanation of symbols]

10 cylinders 14 Pilot shaft 16 pistons 28 First Space 30 Second space 32 Pressure oil hole 38 oil supply passage 40 oil drain 42 Conducting path 44 Air bleeding pipe 46 Orifice 48 oil sump 54 Check valve 56 recess 58 discharge hole 62 Drawing tool 64 Engagement part P particles

Front page continuation (72) Inventor Kazuo Hattori 11-11 Haneda Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (56) References JP-A-2-286901 (JP, A) JP-A-7-208499 (JP, A) JP-A-9-53607 (JP, A) JP-A-5-118352 (JP, A) Actually developed 58-132517 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) F15B 15/14 380 F16D 33/14 F15B 9/00 F15B 21/04

Claims (6)

(57) [Claims] 1. A pilot shaft and a piston arranged in a cylinder, wherein the pilot shaft is rotated so that a passage formed on a surface of the pilot shaft communicates with an oil passage formed on the piston. In the hydraulic servo device that drives the piston in the axial direction, at least two pairs of the oil passage and the conduction passage for driving the piston in the same direction are provided on the piston and the pilot shaft, respectively. A hydraulic servo device, wherein a pair of a conduction path and an oil path is provided such that the rotation angles communicating with each other are deviated. 2. The hydraulic servo device according to claim 1, wherein the conduction path is provided in a non-linear manner with respect to a rotation angle of the pilot shaft. Space 3. Before Symbol cylinder comprises a first space having a pressure oil bore by the piston, communicates through the conductive path with the first space, or the blocked second space are claim is partitioned in the upper portion of the second space, characterized in that the air vent pipe opening into the external space is provided
The hydraulic servo device according to 1 or 2 . Space 4. A front Symbol cylinder comprises a first space having a pressure oil bore by the piston, communicates through the conductive path with the first space, or the blocked second space are It is defined, according to claim 1 or 2, characterized by forming a recess for storing the particles at the bottom of the first and / or second space
The hydraulic servo device described in . 5. A pilot shaft and a piston arranged in a cylinder are provided, and the pilot shaft is rotated so that a passage formed on the surface of the pilot shaft is communicated with an oil passage formed on the piston. In a hydraulic servo device that drives the piston in an axial direction, a space in the cylinder communicates with or is disconnected from a first space having a pressure oil hole by the piston and the first space via the communication path. Is formed in a second space, and an oil sump is formed outside the cylinder on the side of the first space to cover a piston sliding hole formed on a side wall of the side of the first space. A hydraulic servo device. 6. An impeller and an impeller casing attached to a drive shaft, a runner attached to a driven shaft, and a scoop tube whose position is controlled by the hydraulic servo device according to claim 1. A fluid coupling characterized by the following.