JPS60224979A - Variable capacity radial piston motor controller - Google Patents

Abstract

PURPOSE:To achieve highly stable and responsive control by assembling a servo valve in the crank shaft of a radial piston liquid pressure motor and transmitting the variation of movement of an eccentric wheel to a spring contacting through an inclined face with the servo valve. CONSTITUTION:The motor is provided with an eccentric wheel 6 movable around a crank shaft 1 in the casing 4 while more than three pistons 8 are arranged around said wheel 6. While control pistons 24, 25 are fitted in control cylinders 26, 27 provided in said wheel 6 while facing with the crank shaft 1. Here, a servo volve A is arranged integrally at the inner end of the crank shaft 1. Said servo volve A is provided with a spool 28 inserted into a tubular hole 29 and upon up/down motion of the rod 53 caused through the motion of said wheel 6, the rod 52 is moved to the left/right through the inclined faces of the rods 53, 52 thus to vary the energizing force of the spring 51.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application of the present invention relates to a control device for a hydraulic radial piston motor whose capacity can be changed steplessly.

First, a conventional technology related to a control device for this type of hydraulic radial piston motor will be explained.

Conventionally, in order to change the capacity of a hydraulic radial piston motor steplessly, as in Japanese Patent Application No. 47-10921, the eccentric wheel was moved by a control piston and a control cylinder installed in the crankshaft. The amount of eccentricity was changed. In this case, the amount of movement of the six eccentric wheels is controlled by installing a servo valve outside the hydraulic motor, and operating the servo valve by the differential pressure between the relief valve operated by the eccentric wheel and the manual relief valve for adjusting the amount of eccentricity. , the hydraulic fluid was supplied to and discharged from the control cylinder. In this case, since the servo valve is installed outside the hydraulic motor, the fluid passages between the servo valve and the control cylinder, and between the servo valve and the relief valve, are both connected for a considerable distance via the rotating navy blue T. There will be.

It is well known that when performing servo control of a foot bag, the distance between the servo valve and the cylinder described above should be as close as possible to ensure operational stability, reduce hunting, and improve responsiveness. Get better. However, in the past, as the distances between the two sides were disturbed as described above, the main parts of the servo system tended to become unstable, causing hunting and extremely poor response.

This invention was made to solve the above problems, and its purpose is to incorporate a servo valve into the crankshaft so that changes in the amount of movement of the eccentric wheel can be directly transmitted to the servo valve via a spring. The distance between the servovalve and the cylinder is shortened, and the feedback signal is transmitted mechanically rather than via the hydraulic fluid, improving the stability and responsiveness of this servo system. To provide a control device for a radial piston motor that can easily and reliably move an eccentric wheel without causing hunting or the like, and can steplessly change the capacity of the radial piston motor.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show a first embodiment of the invention.

First, the configuration of the main parts that will be a means to solve the problem will be explained.

(2) is a crankshaft which is supported by the case ring 4 and the front cover 5 via bearings 2.3.

An eccentric ring 6 having a substantially rectangular cross section and a cylindrical outer shell is slidably inserted into the intermediate zone of the crankshaft 1 in a manner perpendicular to the axial direction of the crankshaft 1 described above. . Reference numeral 7 denotes a large number of cylinders arranged radially in a radial direction perpendicular to the crankshaft l, passing through the eccentric wheel 6 as described above, as shown in FIG. The figure shows a case of five. 8 is a piston having four spherical parts formed inside. This piston 8 is slidably fitted into the cylinder 7 described above. 9 is the stove °
There is ζ. The tip of the stove throat 9 is formed into a spherical shape, and is fitted into the inner spherical recess of the piston 8 so as to be swingable. Konronodo 9 according to the above
The proximal ends of the guide rings IOA and IOB are positioned in the axial direction by the casing 4 and the front cover 5,
It is in close contact with the eccentric ring 6 in such a manner that it can constantly slide on the outer circumferential surface of the eccentric ring 6 described above.

11 is a cover for sealing the outer surface of the cylinder 7 described above. A seal 12 is inserted into the front cover 5 and seals the crankshaft 1. 13 is a valve casing extending in the direction of the casing 4. This Harp casing 13 has a distribution valve 4 rotatably installed therein.

Note that the distribution valve 14 has grooves 17 and 18 formed at a plurality of locations on the circumferential surface thereof, through which supply and discharge ports H5 and 16, which are bored in the valve casing 13 and which supply and discharge hydraulic fluid, pass through. ing. Further, this distribution valve 14 has an arc-shaped distribution groove 19°20 formed on the base end side. (In FIG. 1, the distribution a20 is formed on the back side of the distribution groove 19.)
In addition, in the distribution valve 14 described above, the distribution grooves 19 and 20 are communicated with f1117 and 18, respectively, by the liquid path 2L22. 23 is a cover for holding down the distribution valve 14 and sealing the valve casing 13.

Control pistons 24, 25 facing each other are arranged in the eccentric wheel 6 so as to be able to move near and far relative to the axis of the crankshaft l by means of control cylinders 26, 27. Each end face of this control piston 24 , 25 rests on the inside of the eccentric 6 and is slidably inserted into a cylindrical control cylinder 26 , 27 provided in the crankshaft 1 . Note that by moving the eccentric position of the eccentric wheel 6 as described above, the distance of the piston 80 stroke can be changed, and the capacity of the control device can be changed.

A servo valve A shown below is integrally disposed at the shaft end of the crankshaft l on the opposite side to the output shaft. This servo valve A is formed as follows. That is, as shown in FIG. 1, a cylindrical hole 29 into which a spool 28 is slidably inserted is bored at the shaft end of the crankshaft 1 described above. In this hole 29, for example, an annular groove 30, a central annular groove 31. An annular groove 32 on the other side is formed respectively. The - side annular groove 30 and the other side annular groove 32 have a liquid passage 33 that passes through a chamber surrounded by the casing 4 and the valve casing 13, the bearing 3, and the inside of the casing 4, and a drain boat bored in the casing 4. 34, and is configured to constantly communicate with a tank of a hydraulic pressure source (not shown). Further, the central annular groove 31 is formed to be a rotary joint by communicating with the liquid passage 35 and communicating with the annular groove 36 provided inside the valve casing 13 and the liquid passage 37. It communicates with a pressure boat 38 bored in the valve casing 13 .

As described above, even when the crankshaft l rotates, the central annular groove 31 and the pressure port 38 are in communication with each other. The spool 28 according to the above is formed with two grooves 39, 40,
The left side a39 in FIG. 1 communicates with the control cylinder 26 on the lower side of the figure through a liquid passage 41 in the crankshaft 1, and the groove 40 on the right side in the figure communicates with the control cylinder 26 on the upper side in the figure through a liquid passage 42. It is connected to 27. Further, the left end of the spool 28 in the figure is formed to be one step narrower. And the eccentricity f of the eccentric wheel 6
The control chamber 43 to which pressure is applied for adjusting the illumination is connected to the sleeve 4.
4. It is provided so as to be surrounded by a cover 45. The control chamber 43 is formed to be a rotary joint by communicating with an annular groove 147 provided in the annular groove 36 of the valve casing 13 through a liquid passage 46 formed in the cover 45 and the crankshaft 1. and a control port 49 bored in the valve casing 13 through the branch 48.
is connected to.

Cover 45 fitted to one end of the servo valve according to the above
is engaged with the Oldham joint 50 and is concentrically connected to the distribution valve 14 disposed in front of it. In this case, the distribution valve 14 described above is configured to rotate in synchronization with the crankshaft 1 described above. Note that the spool 2 mentioned above
A spring 51 is in contact with the right end of 8 in the figure. The other end of the spring 51 is slidably fitted onto the crankshaft l with the rod 52 in contact with the other end. Also, the rod 5
The right end of the rod 2 is formed into a slope, and is in contact with one end of the slope of the rod 53. The other end of the rod 53 is fixed to the eccentric wheel 6 described above, and is slidably fitted onto the crankshaft l. When the eccentric wheel 6 moves, the rod 53 moves up and down in the figure, and due to both the slopes of this rod 53 and the rod 52, when the lot 52 moves left and right, the accumulated force of the spring 51 is generated. is configured so that it changes.

Further, a chamber 54 surrounded by the spool 28 and the sleeve 44, and a chamber 55 in which the spring 51 is provided, are connected to the liquid path 33.
This communicates with the drain boat 34, thereby eliminating the need for hydraulic fluid to enter. 56, the eccentric wheel 6 is connected to the crankshaft 1
This ring is used to restrict movement in the axial direction. Further, the valve casing 13 and the casing 4 are each provided with a liquid passage 57 for supplying and discharging hydraulic fluid to each cylinder 7, and one end of each of the passages 57 is connected to the distribution @ of the distribution valve 14 described above.
The openings are equally distributed around 19.20.

The other end of the liquid passage 57 opens at the upper end of each cylinder 7. In addition, casing 4. Front cover5. Valve casing 13. The covers 11, 23, and 45 are connected to each other by bolts (not shown) or the like. Moreover, each important part is pa.

The sealed state is maintained by locks etc. Necessary measures are taken to prevent the leakage of hydraulic fluid by using seals and the like at each of the above-mentioned main parts during sliding, such as the cylinder and piston, the distribution valve and the valve casing.

Next, the action will be explained.

With the above configuration, as shown in FIGS. 1 and 2,
A case will be described in which the amount of eccentricity of the eccentric wheel 6 is in the maximum state and the amount of eccentricity does not change.

The pressure boat 38 can be supplied with high-pressure hydraulic fluid from a hydraulic pressure source, or can be supplied with hydraulic fluid from the high pressure side of either the supply/discharge boat 15 or 16 via a selection valve. Under the condition that the control boat 49 is connected to a pressure control valve that can arbitrarily change the supply pressure by using a pressure reducing valve, a relief valve, etc. to control the capacity of the hydraulic motor. The pressure in the control boat 49 is made sufficiently low. Then, the pressure of the control boat 49 is reduced to the liquid path 48,
Annular groove 47. Liquid path 46. The above pressure is transmitted to the control chamber 43. Therefore, the pressure in the control chamber 43 decreases, and at the same time, the spool 28 moves to the left in the figure due to the stored force of the spring 51.

As a result, the central annular groove 31 and the groove 40 communicate with the groove 39 and the one side annular groove 30, respectively, and the hydraulic fluid supplied from the pressure port 38 is transferred to the liquid path 37. Annular groove 36, liquid path 35. Central annular groove 31. Groove 40. /& passage 42 and is introduced into the control cylinder 27. One control cylinder 26
The hydraulic fluid flows through the fluid path 41. Groove 39. - Side annular groove 30. Liquid path 33. It passes through a drain boat 34 inside the casing 4 and is connected to a hydraulic tank. That is, as the spool 28 moves to the left, hydraulic fluid is introduced into the control cylinder 27 and the hydraulic fluid in the control cylinder 26 is discharged, so the control piston 25 is pushed out from the control cylinder 27 and the eccentric wheel 6 moves as shown in the figure. The control piston 24 is also pushed upward, but since the hydraulic fluid in the control cylinder 26 is discharged at the same time, the eccentric wheel 6 moves upward and is fixed at the end of its stroke. Even if an external force is applied to this eccentric wheel 6, it will not move.

Next, a directional flow rate switching valve (not shown) is connected to the supply/discharge boat 15.16 from a hydraulic pressure source (not shown), and depending on the switching direction of this switching valve, the supply/discharge boat 15.16 can be configured to supply, Evacuation can be performed, thereby changing the direction of rotation of the hydraulic morph and at the same time adjusting its flow rate to control its rotational speed.

For example, if the hydraulic fluid discharged from the hydraulic pressure source is supplied to the supply/discharge bow 15 by switching the aforementioned switching valve (not shown),
The above-mentioned hydraulic fluid flows from the groove 17 through the liquid path 21 to the distribution groove 19.
reach. Since this distribution groove 19 communicates with the cylinder 7 which is in the downward stroke in the axial direction of the crankshaft l via the fluid passage 57, the working fluid from the hydraulic pressure source is supplied to the distribution 'a19 indicated by "-". will be done. Therefore, the piston 8 is pushed down, and at the same time, the stove throat 9 is also pushed down. At this time, since the eccentric wheel 6 is pushed in the required rotation direction, the eccentric wheel 6 rotates in the same direction. As a result, as shown in Fig. 2, torque is transmitted through the engagement between the left and right inner surfaces of the eccentric wheel 6 and the left and right outer surfaces of the crankshaft l, so that the crankshaft 1 rotates in the required direction. can be started.

When the eccentric wheel 6 rotates as described above, the piston 8 of the cylinder 7, which is in the upward stroke, rises via the stove throat 9, so that the hydraulic fluid in the cylinder 7 is
820. Liquid path 22. Groove 1B.

It passes through the supply/discharge boat 16 and further passes through a switching valve (not shown) to be discharged into the tank of the hydraulic pressure source. Furthermore, when the crankshaft 1 rotates as described above, the distribution valve 14 also rotates synchronously via the Oldham joint 50. Therefore, since hydraulic fluid is supplied to the cylinder 7 on the downward stroke and hydraulic fluid is discharged from the cylinder 8 on the upward stroke, the fluid passages 57 are switched one after another, so that the crankshaft is continuously Can be rotated.

When reversing the hydraulic morph, the supply/discharge boat 1-16 is connected to the hydraulic pressure source, and the supply/discharge boat 15 is connected to the tank by a switching valve. That is, when the hydraulic morph rotates in the normal direction, the cylinder 7 on the upward stroke is switched to the downward stroke, and the cylinder 7 on the downward stroke is switched to the upward stroke, depending on the rotational direction of the eccentric wheel 6. The crankshaft can be rotated in the opposite direction by supplying hydraulic fluid and discharging the hydraulic fluid in the cylinder 7 during the upward stroke to the tank of the hydraulic pressure source.

The operation described above is the same as that of a normal constant displacement radial piston motor. In this invention, by changing the amount of eccentricity of the eccentric wheel 6 of the hydraulic motor, the reciprocating stroke of the piston 8 can be changed, and at the same time, the capacity (discharge ii) per revolution of the crankshaft 101 can be changed. This is easily possible by supplying and discharging the hydraulic fluid from the control cylinders 26 and 27.

Next, a method of controlling the movement of the eccentric wheel 6 will be explained.

To reduce the amount of eccentricity from the state shown in FIG. 1, first increase the pressure in the control port 49, then the branch 48. The above pressure is transmitted to the liquid path 4G and the control chamber 43. Therefore, the pressure in the control chamber 43 increases and at the same time the spool 2
No. 8 moves to the right in the figure while increasing the spring 51 by 53%. As a result, the central annular groove 31 and the groove S9 communicate with /1640 and the other annular groove 32, respectively, and the hydraulic fluid supplied from the pressure boat 38 is transferred to the liquid path 37. Annular groove 3G.

Liquid path 35. Central annular groove 31. *39. >i path 4J and is introduced into the control cylinder 26. On the other hand, the hydraulic fluid in the control cylinder 27 flows through the hydraulic fluid path 42°s40. Other side annular groove 32. Liquid path 33. It passes through the drain boat 34 inside the casing 4 and is connected to a tank of a hydraulic pressure source. That is, as the spool 28 moves to the right, hydraulic fluid is introduced into the control cylinder 26 and hydraulic fluid from the control cylinder 27 is discharged, so that the control piston 24 is pushed out from the control cylinder 26 and the eccentric wheel 6 moves as shown in the figure. As it moves downward, the control piston 25 is also pushed downward, but since the hydraulic fluid in the control cylinder 27 is discharged at the same time, the eccentric wheel 6 moves downward and its eccentricity decreases.

When the eccentric wheel 6 moves downward in the figure as described above, the rod 5
3 also moves in the same direction at the same time, and the above movement is converted into a direction perpendicular to the previous movement by the tip slope of the mouth/door 53 and the slope of the rod 52.
2 moves to the left in the figure. In other words, as the spring 51 accumulates force due to the movement of the eccentric wheel 6, the spool 28 also moves to the left at the same time. In this case, when the stored force of the spring 51 balances the rightward acting force due to the pressure of the spool 28 acting on the control chamber 43 at the position of the spool 28 in FIG.
．． Supply of hydraulic fluid to '21.

Ru.

Next, when increasing the capacity of the hydraulic motor by decreasing the amount of eccentricity, if the pressure in the control port 49 is lowered, the pressure in the control chamber 43 will also be lowered at the same time, so the accumulated force of the spring 51 will be greater. The spool 28 moves to the left in the figure. Therefore, hydraulic fluid from pressure port 38 is transferred to fluid path 37. Annular groove 36, liquid path 35, central annular i31. Groove 40. Liquid path 42.
It enters the control cylinder 27. As a result, the control cylinder 26
The hydraulic fluid flows through the fluid path 41. Fully 39. - Example annular groove 30, liquid path 33. It is discharged from the inside of the casing 4 and from the train boat 34 to the tank of the hydraulic pressure source. In other words, when the eccentric wheel 6 moves upward in the figure, the mouth 53 also moves upward at the same time, and the rod 52 moves to the right, so the stored force of the blade 51 decreases and the spool 28 also moves to the right. will be moved to. As described above, when the pressure in the control chamber 43 and the accumulated force of the spring 51 are balanced with the spool 28 in the state shown in FIG.
The supply and discharge of hydraulic fluid to 6.27 also stopped at the same time,
This also causes the eccentric wheel 6 to stop.

As explained above, by changing the pressure in the control port 49, the position of the eccentric wheel 6 can be arbitrarily changed, thereby changing the capacity of the hydraulic motor.

Note that the external force from the piston 8 is constantly changing and applied to the eccentric @ 6 during rotation of the crankshaft, and the spool 28 has a slight leakage of hydraulic fluid for smooth operation, so the eccentric wheel 6 is Although it is caused to move upward by an external force, the movement of the spool 28 generates a force that resists the force. For example, when the eccentric wheel 6 moves upward in the figure due to the action of an external force, the mouth 53 moves upward at the same time. Therefore, the rod 52 also moves to the right in the figure, the stored force of the blade 51 decreases, the previous balance is lost, and the spool 28 moves to the right, but the hydraulic fluid from the pressure boat 38 , the control cylinder 26 as described above.
, a resistance force is generated that tends to move the eccentric wheel 6 downward, and further movement of the eccentric wheel 6 can be completely prevented. Conversely, even if the eccentric wheel 6 attempts to move downward, pressurized hydraulic fluid is introduced into the control cylinder 27 via the spool 28, thereby preventing the eccentric wheel 6 from moving further. This can be easily and reliably prevented. That is, movement of the eccentric wheel 6 due to external force can be prevented, and the set amount of eccentricity can be reliably maintained.

FIG. 3 shows a second embodiment of the invention.

In this embodiment, a lot 52, a rod 53 . Liquid path 41. ．． Each of the 42 connections is different. Therefore, by increasing the pressure in the control port 49, the amount of eccentricity of the eccentric wheel 6 can be increased. That is, as shown in FIG. 3, the pressure in the control port 49 is at its maximum, and the eccentricity! Since the eccentricity of &6 is also at its maximum, the stored force of the wing 51 is also at its maximum.

In the case of this second embodiment, the supply/discharge port 15. ] 6 to the control port 49 via the selection valve.
If the load on the hydraulic motor is large and the pressure is high, the amount of eccentricity of the eccentric wheel 6 will also increase. Therefore, when the capacity of the hydraulic motor increases and the load on the hydraulic motor is small and the pressure is low, the amount of eccentricity of the eccentric wheel 6 also decreases.
The capacity of the hydraulic motor will be reduced. As a result, when the same flow rate is supplied to the supply/discharge port 15 or 16,
When the load is large, the capacity of the hydraulic morph increases, so it rotates at a low speed, and when the load is small, the capacity of the hydraulic motor decreases, so it rotates at a high speed to keep the horsepower constant. can have similar performance.

In this example, the number of cylinders 7 is shown as five, but
The number of cylinders 7 according to the present invention is not limited, and any number may be used as long as there are three or more cylinders, for example.

Further, although the Oldham joint 50 is used to transmit the rotation of the crankshaft 1 to the distribution valve 14, any joint may be used as long as the rotational force can be transmitted synchronously.

This fruit bl! ! In the example, from the pressure port 38 to the central annular groove 3
1 and the passage from the control port 49 to the control chamber 43 use rotary joints with annular grooves 36 and 47. Even if the hydraulic motors are rotated from the outside of the casing 4 or the valve casing 13, it is sufficient that the respective main parts are communicated with each other.

Similarly, the liquid passage 33 is discharged through the inside of the goo song 4 and the tren port 34, but if it is necessary to consider back pressure etc., the pressure port) 38. As with the control port 49, it may also be connected directly to the tank via a rotary joint.

In addition, each slope of the rods 52 and 53 converts the movement of the eccentric wheel 6 so that it is perpendicular to the axis of the crankshaft 1.
However, in this case, the mechanism for converting the load into a load may be a link mechanism, a mechanism in which a cam is incorporated into the arm and the pinion, etc., as long as it can convert the load in the same orthogonal direction.

Furthermore, the combination of transmitting the movement of the eccentric wheel 6 to the spool 28 via the spring is the combination of the eccentric wheel 6. Orthogonal exchange.

Hane 51. Instead of the spool 28, for example, the eccentric wheel 6, the spring 51. Orthogonal exchange or spool 28 may also be used.

Although the embodiment describes a hydraulic morph using an eccentric with a cylindrical outer surface, the present invention also relates to a hydraulic motor having an eccentric with a polygonal outer surface and a piston sleeve, such as described in British Patent No. 886,923. Of course, the present invention can also be applied to a hydraulic motor such as the one shown in FIG.

As explained in the above embodiments, the present invention incorporates a servo valve into the crankshaft and transmits changes in the amount of movement of the eccentric wheel via the slope to the spring that contacts the servo valve. The distance between the servo valve and the cylinder for moving the eccentric wheel can be shortened. Furthermore, since the feedback signal is generated mechanically without going through the hydraulic fluid, this servo system has good stability and good response.

Furthermore, the eccentric wheel can be moved by control pressure without causing hunting or the like.

Also, compared to the case where a servo valve or switching valve is installed at the same time as the setting of the t-pressure moke to change the amount of eccentricity of the eccentric wheel,
The capacity of the hydraulic JE motor can be changed without changing the external dimensions of the hydraulic motor, and the installation area can be greatly reduced by eliminating the need for equipment to be mounted on an inclined section.

Furthermore, compared to Japanese Patent Application No. 47-10921, the number of wave paths for controlling the eccentric wheel can be reduced from three to two, thereby reducing the installation area and cost.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 shows a radial piston motor according to a first embodiment of the present invention, indicated by δ on the line 1-1 in FIG.
This figure is a longitudinal sectional view of the same motor taken along the line 11--U in FIG. 1, and FIG. 3 is a longitudinal sectional view of the same motor according to the second embodiment. 180. Crankshaft 2. 3. ,,bearing 400. Casing 510. Front cover 611. Eccentric wheel 71
．． Cylinder 841. Piston 900. Conronnod 10A, IO
B., Guide ring 11, 23.45. , , cover 126. Seal 13, Hull casing 14, Distribution valve 15.16. , , Supply and discharge boat 1
7.18.3'l, 40. ,,/W 19,20. ,,
Distribution groove 2L22.33.35,37,4], 42,46
, 48, 57. ,, liquid path 24.25. ,,control piston 26.27. ,,control cylinder 28,,,spool 29. ,, Hole 30 , - An example of an annular groove 31. ,,central annular groove 32,
,,Other side annular groove 34. ,, drain boat 36.47.
,, annular groove 38. , , Pressure boat 43 , , Control room 44. , , Sleeve 49 , , Control boat 5
09. Oldham joint 51... Hane 52.53. ,,
Rod 54.55. ,,room 56. ,,Ring A19.
servo hull

Claims (1)

[Claims] a casing, a crankshaft supported within the casing, an eccentric wheel movably provided around the crankshaft within the casing, and a plane passing through the eccentric wheel and perpendicular to the axis of the crankshaft. three or more cylinders arranged in a radial manner, a piston that is slidably inserted into the cylinder so that its base is always slidably in close contact with the outer circumferential surface of the eccentric ring; a control cylinder surrounded by and provided to face the crankshaft;
a set of control pistons slidably fitted in said control cylinder and abutting the inside of said eccentric, and further by rotation thereof for actuating a hydraulic motor and for rotating said eccentric; A radial piston hydraulic motor includes a distribution valve for supplying and discharging working fluid to and from the cylinder rotatably connected to the crankshaft in order to rotate the crankshaft, the radial piston hydraulic motor having a servo in the crankshaft. A valve is provided in the axial direction, and a spool that enables control pressure to be introduced against internal springs is slidably inserted into one end of the servo valve, and the eccentric wheel is installed at the other end of the servo valve. A variable displacement radial piston motor control device, characterized in that the movement of the variable displacement radial piston motor is transmitted through the internal spring and a mechanism that converts the movement of the motor so as to be perpendicular to the axial direction.