JP2001329940A - Hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic motor capable of processing working fluid leaking to the inside of a motor casing without using any drain pipe. SOLUTION: In a radial piston type hydraulic motor 7, for example, drain relief means 39, 40 constructed of a relief passage 41 and a check valve 42 arranged in the relief passage 41 are arranged inside a distribution valve 35 of the motor. One end of the passage 41 is communicated with the inside of the motor casing 22, while the other end communicates with an oil port 32/33 of a valve casing 25. The valve 42 allows outflow of the working fluid from the inside of the casing 22 to the oil port 32/33 on the low-pressure side. The working fluid leaking inside the casing 22 is discharged to the oil port 32/33 according to opening of the valve 42 for one means 39/40 when an internal pressure of the casing 22 is increased above a valve opening pressure of the valve 42. In this way, leaking oil inside the casing 22 is processed by the hydraulic motor itself without using any drain pipe reaching an oil tank on an intake side of the hydraulic pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic motor such as a radial piston type hydraulic motor configured as a low-speed star-type high-torque hydraulic motor.

[0002]

2. Description of the Related Art For example, a radial piston type hydraulic motor as a low speed star type high torque hydraulic motor is disclosed in
No. 1321 is known. This hydraulic motor is
Along with sequentially supplying and discharging hydraulic oil to a plurality of cylinders provided at equal intervals radially around the output shaft, rotation of the output shaft is performed based on the movement of a plurality of pistons sliding in these cylinders. It is something to convert. In order to continuously supply and discharge the hydraulic oil to and from each cylinder, a distribution valve interlocking with the output shaft is provided, and the rotation of this valve causes the hydraulic oil supplied from the supply-side oil port to be supplied to each cylinder. And the hydraulic oil extruded from the cylinder is discharged to a discharge-side oil port.

Since the hydraulic oil guided to the supply-side oil port of the hydraulic motor has a high pressure, a slight clearance between the distribution valve and the surrounding valve casing, and a slight clearance between the piston and the surrounding cylinder. Through the clearance, part of the hydraulic oil leaks into the motor casing in which the piston, the output shaft and the like are housed. For this reason, conventionally, a drain port is provided in a motor casing of a hydraulic motor, and hydraulic oil leaked into the motor casing is discharged through the drain port.

Supply and discharge of hydraulic oil to and from the hydraulic motor are performed using a hydraulic pump. Therefore, the hydraulic pipe provided between the hydraulic motor and the hydraulic pump includes an oil supply pipe communicating the discharge port of the hydraulic pump and a supply-side oil port of the hydraulic motor, and an oil tank and a hydraulic motor on the suction side of the hydraulic pump. A drain pipe connecting the drain port to the oil tank, and a drain pipe connecting the drain port to the oil tank.
I need a system. Therefore, the hydraulic equipment including the hydraulic motor, the hydraulic pump, and the hydraulic piping has a complicated structure and a high cost.

[0005] In particular, when a hydraulic motor is used as a drive source of a winch or the like in a ship, a hydraulic pump is usually installed at a place several tens of meters away from the place where the motor is installed. In such a hydraulic equipment in which the hydraulic motor and the hydraulic pump are disposed remotely,
Naturally, the hydraulic piping that is routed between these two parts also requires a long time, so it takes time to lay the drain piping, and there are many problems such as an increase in the weight of the ship.
The measures are desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic motor capable of treating a hydraulic fluid leaking into a motor casing without using a long drain pipe.

[0007]

SUMMARY OF THE INVENTION The present invention provides a motor casing, a valve casing connected to the casing,
A distribution valve built in the valve casing with one end face facing the motor casing, an output shaft rotatably mounted on the motor casing and interlocking the distribution valve, and a pair of ports provided in the valve casing And a hydraulic motor including conversion means built in the motor casing and converting energy of hydraulic fluid supplied / discharged through the pair of ports into rotational force of the output shaft.

In order to solve the above-mentioned problem, a pair of drain relief means are provided in the valve casing for releasing the hydraulic fluid leaked into the motor casing to the port on the low pressure side, and these drain relief means are provided. A relief passage communicating between the low-pressure side port and the inside of the motor casing, and a check valve attached to this passage and allowing outflow of hydraulic fluid from inside the motor casing to the low-pressure side port, and One drain relief means is operably provided when the output shaft is rotating in one direction, and the other drain relief means is operably provided when the output shaft is rotating in the other direction. It is a feature.

The present invention can be suitably used, for example, in a low-speed star-type high-torque hydraulic motor in which the arrangement of a plurality of cylinders is a star among radial piston-type hydraulic motors. The present invention can be applied to a radial piston type hydraulic motor or the like which is a type or a series type.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 7 is a schematic plan view of a ship provided with hydraulic equipment having a hydraulic motor according to one embodiment, in which 1 is a hull, and 2 and 3 are on a bow side and a stern side of the hull 1. Each of the lamps is provided so as to be able to be raised and lowered on a horizontal support shaft (not shown) as a fulcrum, and reference numeral 4 denotes a quay of a harbor.

Both lamps 2 and 3 are turned upside down using winches 5 and 6 installed near them. Each of the winches 5 and 6 includes a hydraulic motor 7 as a hydraulic motor, and is operated using the motor 7 as a drive source.

[0013] The first place where the winch 5 on the bow side is installed, in other words, the first place where the hydraulic motor 7 is installed, is remote from the first installation place of the hydraulic motor 7 by a distance of several tens of meters (for example, about 30 meters) toward the center of the hull 1 in the longitudinal direction. A pump placement chamber A in which a hydraulic pump 8 as a hydraulic pump is installed is provided at the two installation locations. The hydraulic motor 7 and the hydraulic pump 8 are communicated with each other via two hydraulic pressure pipes which are routed to the hull 1, that is, an oil supply pipe 9, an oil discharge pipe 10, and a switching valve (not shown). Similarly, a stern-side winch 6 is installed, in other words, a tens of meters (for example, approximately 30 meters) remote from the first installation location of the hydraulic motor 7 toward the center of the hull 1 in the longitudinal direction. Another pump arrangement chamber B in which the hydraulic pump 11 is installed is provided at the two installation locations. The hydraulic motor 7 and the hydraulic pump 11 are connected to the hull 1 through these two hydraulic pressure pipes, that is, oil supply pipes 12,
The connection is made through an oil drain pipe 13 and a switching valve (not shown).

A hydraulic motor 7 for the winch 5 on the bow side;
The hydraulic pump 8, the oil supply pipe 9, the oil drain pipe 10, and the switching valve (not shown) constitute a first hydraulic equipment (hydraulic equipment) 14. Similarly, the hydraulic motor 7, the hydraulic pump 11 of the The oil supply pipe 12, the oil discharge pipe 13, and the switching valve (not shown) are provided with a second hydraulic equipment (hydraulic equipment) 15
Is composed.

Next, a description will be given of the hydraulic motor 7 of the same configuration provided in both of the facilities 14 and 15 with reference to FIGS. The hydraulic motor 7 is configured as a low-speed star-type high-torque hydraulic motor.

That is, in FIG. 1 and FIG. 2, reference numeral 22 denotes a motor casing.
3, a bearing box 24, a valve casing 25,
An end cover 26 is attached.

As shown in FIG.
Has a plurality of, for example, five cylinders 27 (in the following description, when it is necessary to identify and describe each cylinder, the description will be given with subscripts a to e).
These cylinders 27 are radially protruded at equal intervals around an output shaft to be described later, and are arranged in a star shape. Each cylinder 2
Cylinder covers 23 that close their distal openings in a liquid-tight manner are individually connected to the distal end portions 7 by bolting or the like. The motor casing 22 has oil passages 28 as five liquid passages which are located on the rear side thereof and individually communicate with the insides of the cylinders 27 (only one is shown in FIG. In the case where it is necessary to identify and describe each oil passage, the description will be given with subscripts a to e.). Also, the motor casing 22
A rear bearing 29 composed of a tapered roller bearing or the like is attached to a central portion on the rear side.

A bearing box 24 for closing the front opening in a liquid-tight manner is connected to a central portion of the front side of the motor casing 22 by bolting or the like. Inside the box 24 is a tapered roller bearing or the like. Is mounted corresponding to the rear bearing 29. The output shaft 31 is rotatably supported by the bearings 29 and 30. The output shaft 31 penetrates the bearing box 24, and an eccentric cam portion 31a is provided in a portion between the bearings 29 and 30 of the shaft 31. E in FIG. 2 indicates the amount of eccentricity of the center axis of the eccentric cam portion 31a with respect to the center axis of the output shaft 31.

The valve casing 25 is connected to the rear side of the motor casing 22 by means of bolts or the like while maintaining a liquid-tight state. The cover 26 is connected by bolting or the like. Valve casing 25
Oil ports 32, 33 as a pair of ports are provided side by side in the peripheral portion of. One oil port 32 is connected to the hydraulic pump 8 via the oil supply pipe 9 or 12 via the switching valve (not shown).
Or, it is communicated with 11 discharge ports. The other oil port 33
Also, the oil drain pipe 10 or 13 communicates with an oil tank (not shown) through the switching valve (not shown). Furthermore,
The valve casing 25 is provided with an oil passage 34 as a liquid passage individually communicating with the oil passages 28 (note that only one oil passage is shown as a representative in FIG. In some cases, the description will be given with subscripts a to e.).

In the valve casing 25, a distribution valve 35 for supplying and discharging hydraulic oil to and from each cylinder 27 in a predetermined order is rotatably accommodated. The valve 35 has two oil passages 36 in the valve (only one is shown in FIG. 1) as two liquid passages in the valve always communicating with the oil port 32, and two valves always communicating with the oil port 33. A valve internal oil passage 37 (only one is shown in FIG. 1) as an internal liquid passage is provided. When the distribution valve 35 is rotated, the oil passage 36 in the valve communicates with the oil passage 34 communicating with the cylinder 27 in the suction process, and the oil passage 37 in the valve moves in the cylinder in the discharge process. The oil passage 34 communicates with the oil passage 34.

The distribution valve 35 is provided on the same axis of the output shaft 31 and is arranged side by side in the direction in which the axis extends. The end face of the distribution valve 35 on the output shaft 31 side is located inside the motor casing 22. I'm coming. The distribution valve 35 and the output shaft 31 are connected to the Oldham coupling 38.
, So that the distribution valve 35 is rotated in synchronization with the output shaft 31. In addition,
In FIG. 3, reference numeral 35a denotes a long groove for engagement with the Oldham coupling 38.

As shown in FIG. 3, a pair of drain relief means 39, 40 are provided in the distribution valve 35.
The outlets (drain ports) of the drain relief means 39 are connected to the oil tank (not shown) through the oil drain pipe 10 or 13.

One drain escape means 39 is provided with an escape passage 41 formed by a stepped hole in which a large diameter hole portion formed of a screw hole and a small diameter hole portion are continuous, and a depth of the large diameter hole portion of the passage 41. And a check valve 42 which is screwed in until it reaches the part. The large-diameter hole portion of the relief passage 41 opens to the end face of the distribution valve 35 on the output shaft 31 side and communicates with the motor casing 22, and the small-diameter hole opens to the valve oil passage 37.
The oil port 33 communicates with the oil port 33 through the oil passage 37.
As shown in FIG. 4, the check valve 42 is configured to bias a valve body 42b, which is brought into contact with and separated from the valve seat 42a, toward the motor casing 22 by a spring 42c. The valve body 42b separates from the valve seat 42a only when
This allows the leakage of oil (hydraulic oil) from inside to the discharge-side oil port 33.

Similarly, the other drain escape means 40
Also, an escape passage 43 formed by a stepped hole in which a large-diameter hole portion and a small-diameter hole portion formed of a screw hole are continuous,
And a check valve 44 which is screwed in until reaching the deep part of the large-diameter hole. The large-diameter hole portion of the relief passage 43 is opened to the end face of the distribution valve 35 on the output shaft 31 side and communicates with the motor casing 22, and the small-diameter hole is opened to the valve oil passage 36. And communicates with the oil port 32. Since the check valve 44 has the same configuration as the check valve 42, the description thereof is omitted. However, the check valve 44 allows the leakage of oil (operating oil) from the inside of the motor casing 22 to the oil port 32.

As shown in FIGS. 1 and 2, each of the cylinders 27 is provided with a piston 45 (when it is necessary to identify and describe each piston 45 in the following description, a suffix a To e) are slidably accommodated. A cylinder chamber S is provided between the tip end surface of the piston 45 and the inner surface of the cylinder 27 (in the following description, when it is necessary to identify and describe each cylinder chamber, affixes a to e are attached). Each of the cylinder chambers S is provided with the oil passage 2.
8 are communicated individually. Each piston 45 is connected to the spherical head 46a of the connecting rod 46 via a socket bush 47 so as not to be separated. The spherical head 46a and the piston 45 are slidable. The base end 46b of each connecting rod 46 is slidably contacted with the outer peripheral surface of the eccentric cam portion 31a, and a stop ring 48 is fitted over the base end 46b so as to maintain the slidable contact state. Have been.

In the hydraulic motor 7 having the above configuration,
The pistons 45, the connecting rods 46, the eccentric cam portions 31a of the output shaft 31 and the like inserted into the cylinder 27 are connected to the high pressure side oil port, for example, the oil chamber 32 from the oil chamber 32 to the suction side cylinder chamber. While converting the energy of the hydraulic oil discharged from the discharge side cylinder S to the low pressure side oil port, for example, the oil port 33, into the rotational force of the output shaft 31.

Next, the operation of the hydraulic motor 7 will be described with reference to FIGS. In this operation description, 2 in FIG.
8a to 28e indicate oil passages formed in the motor casing 22 with one end individually communicating with the five oil passages 34a to 34e and the other end individually communicating with the cylinder chambers Sa to Se, respectively. In FIG. 5, 45a to 45e indicate five pistons individually inserted into the cylinder chambers Sa to Se, and in FIG. 6, 34a to 34e indicate five oil passages of the valve casing 25, respectively. ing.

In the state shown in FIG. 5 and FIG.
Or, when hydraulic oil as high-pressure hydraulic fluid is supplied to the oil port 32 from the oil supply pipe 9 or 12 through the oil supply pipe 9 or 12, the oil is communicated with the two valve oil passages 36 in the state of the distribution valve 35 shown in FIGS. Through the oil passages 34d and 34e and the oil passages 28d and 28e,
High-pressure hydraulic oil is supplied to the two piston chambers Sd and Se communicating with 8e. Therefore, pistons 45d, 4
5e are pushed toward the output shaft 31, respectively, so that the piston 4
5d and 45e exert a clockwise rotation force in FIG. 5 on the output shaft 31 based on the component force F1 of the force F0 pressing the output shaft 31 via the connecting rod 46.
The body itself slides on the cam surface of the eccentric cam portion 31a.

With the rotation of the output shaft 31 at this time, the pistons 45b and 45c connected to the connecting rod 46 pushed by the eccentric cam portion 31a reduce the volumes of the piston chambers Sb and Sc into which they are inserted. The hydraulic oil in the piston chambers Sb, Sc is moved by the oil passages 28b,
Each is extruded through 28c. The hydraulic oil thus extruded passes through the two valve oil passages 37 communicating with the oil passages 28b and 28c in the state of the distribution valve 35 shown in FIG. It is discharged outside. The hydraulic oil that has passed through the oil port 33 is returned to the suction port side of the hydraulic pump 8 or 11 via the drainage pipe 10 or 13 and is again supplied to the hydraulic motor 7 by the pump 8 or 11. You.

Although the piston indicated by reference numeral 45a in FIG. 5 is in a neutral state, the output shaft 31 is rotated clockwise as described above, and at the same time, the distribution valve 35 is rotated clockwise through the Oldham coupling 38. , The high-pressure hydraulic oil next acts on the piston 45a.

Thus, always two or three pistons 45
Since the high pressure hydraulic oil acts on and the above operation is repeated, the rotational force is continuously applied to the output shaft 31 via the connecting rod 45 connected to the piston on which the high pressure hydraulic oil has acted. The shaft 31 can be rotated in one direction.

The flow direction of the hydraulic oil pumped by the hydraulic pump 8 or 11 is switched by a switching valve or the like (not shown) to introduce high-pressure hydraulic oil into the oil port 33.
When the discharged hydraulic oil is discharged through the oil port 32, the oil port 32 is used as a discharge side where the pressure is low,
The oil port 33 is used as a high pressure supply side and the output shaft 3
The rotation direction of 1 is opposite to that described above.

In the above operation, when a high pressure is applied to each cylinder chamber S, part of the hydraulic oil leaks into the motor casing 22 through a slight clearance between the cylinder 27 and the piston 45, and the valve A part of the hydraulic oil leaks into the motor casing 22 through a small clearance between the casing 25 and the distribution valve 35. Then, the pressure inside the motor casing 22 due to such a leak is reduced by the drain relief means 3 on the low pressure side.
When the force of the spring 42c of the ninth check valve 42 exceeds the urging force, the valve body 42b is pushed against the spring 42 at that moment, and the check valve 42 is opened.

In this case, the pressure from the one oil port 32 to which the operating oil is supplied to the cylinder chamber S has the highest pressure, and the other oil port 3 from the cylinder chamber S from which the operating oil is discharged to the other oil port 3
3 is the lowest, and the motor casing 22
Internal pressure varies in a pressure range from a pressure lower than the highest pressure to the lowest pressure. Therefore, the check valve 42 of the drain relief means 39 connected to the other low pressure side oil port 33 is opened as described above. At this time,
With respect to the other drain relief means 40, the valve body 42b of the check valve 44 receives the hydraulic pressure of the high-pressure hydraulic oil together with the urging force of the spring 42c and is pressed and held on the valve seat 42a. The check valve 44 of the drain escape means 40 is not opened.

As described above, the drain relief means 3 on the low pressure side
When the check valve 42 of No. 9 is opened, it passes through the relief passage 41 and the valve oil passage 37 communicating therewith.
Hydraulic oil (oil leakage) leaking into the motor casing 22 can be discharged to the low pressure side oil port 33 as a drain port and collected in the oil tank tank or the like on the suction side of the hydraulic pump 8 or 11. Therefore, the oil drain pipe 10 or 13 can be used as a drain pipe to return oil leakage in the motor casing 22 to the suction port side of the hydraulic pump 8 or 11.
A long drain piping routed around the hydraulic motor 7 and the hydraulic pump 8 or 11 can be omitted.

As a result, the number of hydraulic pipes required for the hydraulic equipments 14 and 15 can be reduced from three to two in the related art, and the piping work for the hydraulic equipments 14 and 15 is reduced, and the cost is reduced. Hydraulic equipment 14, 15 can be configured with
It also helps to reduce the weight of the ship.

Since the hydraulic motor 7 has another drain relief means 40 communicating with the oil port 32, even if the rotation direction of the output shaft 31 is changed to the opposite direction as described above, When the pressure in the motor casing 22 rises above the valve opening pressure of the check valve 44, the drain relief means 40
With the opening of the check valve 44, the oil leak in the motor casing 22 can be discharged to the oil port 32 as a drain port through the escape passage 43 and the valve passage 36 communicating with the escape passage 43. In this case, the oil supply pipe 9 or 12 is used as a drain pipe so that the oil leakage is caused by the hydraulic pump 8 or 1.
1 is returned to the suction port side. As described above, in the hydraulic motor 7 including the drain relief means 39 communicating with the oil port 33 and the drain relief means 40 communicating with the oil port 32, the hydraulic pump 8 is provided regardless of the rotation direction of the output shaft 31. Alternatively, oil leakage in the motor casing 22 can be discharged without using a drain pipe connected to the motor casing 11.

Further, since both the drain relief means 39 and 40 are provided in the distribution valve 35, there is no need for special parts for communicating the inside of the motor casing 22 with the oil port 32 or 33. Since the number of parts constituting the drain relief means 39 and 40 is small, the configuration of these means 39 and 40 is simple and the cost can be reduced. Moreover, as described above, since the two drain relief means 39, 40 are provided in the distribution valve 35, it is not necessary to provide a special space for disposing these means 39, 40, and the hydraulic motor 7 The hydraulic motor 7 of the present invention can be easily manufactured by forming a relief passage in the distribution valve of the existing hydraulic motor 7 and incorporating a check valve in the large-diameter hole. It can be easily realized.

The present invention is also applicable to different types of hydraulic motors such as an axial piston type hydraulic motor.
In the present invention, the specific configuration of the drain relief means is not limited to the configuration of the above-described embodiment. For example, a drain port is provided in a motor casing, and a short port that communicates the drain port with the low-pressure side port is provided. A drain pipe is arranged around the motor casing, and a check valve is provided in this pipe to allow the hydraulic fluid to flow out of the motor casing to the low-pressure port, and the hydraulic fluid leaking into the motor casing is collected in the low-pressure port. Alternatively, if necessary, any configuration may be used as long as the hydraulic motor itself can handle hydraulic oil leaked into the motor casing.

Therefore, the energy of the hydraulic fluid supplied to one of the pair of ports and discharged to the other of the pair of ports is converted by the conversion means built in the motor casing in which the output shaft is rotatably mounted. The present invention can be applied to a hydraulic motor that converts the rotational force of the output shaft. For example, as shown in the above-described embodiment, the hydraulic fluid is supplied from one port of the valve casing and discharged to the other port of the valve casing. Accordingly, an output shaft rotatably mounted on the motor casing is rotated by a piston individually sliding within a plurality of cylinders of the motor casing, and a distribution valve built in the valve casing is interlocked with the output shaft. It can also be applied to a hydraulic motor that rotates and sequentially supplies and discharges to and from each cylinder by this distribution valve. And, in these hydraulic motors, by providing a drain escape means for allowing the hydraulic fluid leaking into the motor casing to escape to the low pressure side port, the hydraulic fluid leaking into the motor casing is drained to the low pressure side port by the drain escape means. The liquid can be discharged and returned to the liquid tank on the suction side of the hydraulic pump for driving the hydraulic motor of the present invention using the pipe connected to the low pressure side port. Since the hydraulic motor itself treats the hydraulic fluid leaking into the motor casing, it is possible to provide a hydraulic motor that does not need to use a drain pipe from the hydraulic motor to the liquid tank.

[0041]

According to the present invention, there is provided a relief passage communicating between a low pressure side port of a valve casing and the inside of a motor casing, and a check valve attached to this passage to allow the hydraulic fluid to flow out of the motor casing to the low pressure side port. And a pair of drain relief means formed in the distribution valve provided with one end face facing the motor casing, so that a special part for communicating the inside of the motor casing with the port of the valve casing is provided. There is no need, and the drain escape means can be configured simply and at low cost with a small number of parts. Since one drain relief means is operably provided when the output shaft is rotating in one direction, and the other drain relief means is operably provided when the output shaft is rotating in the other direction. Regardless of the rotation direction of the output shaft, when the internal pressure of the motor casing becomes higher than the valve opening pressure of the check valve, the check valve is opened to release the hydraulic fluid leaking into the motor casing. It is possible to provide a hydraulic motor that can be discharged through the passage to the low-pressure side port and that can process the hydraulic fluid leaking into the motor casing without using a long drain pipe.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a hydraulic motor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line ZZ in FIG.

FIG. 3A is a front view of a distribution valve provided in the hydraulic motor of FIG. 1; (B) is a side view which shows the distribution valve with which the hydraulic motor of FIG. 1 is provided in partial cross section.

FIG. 4 is a sectional view showing a configuration of a check valve provided in the valve of FIG. 3;

FIG. 5 is a schematic view taken along the line ZY in FIG. 1 for explaining the force acting on the piston of the hydraulic motor in FIG. 1;

FIG. 6 is a schematic view taken along line XX in FIG. 1 for explaining supply and discharge of hydraulic oil to and from a valve of the hydraulic motor in FIG. 1;

FIG. 7 is a schematic plan view of a ship provided with hydraulic equipment having the hydraulic motor of FIG. 1;

[Explanation of symbols]

 7 ... Hydraulic motor 8, 11 ... Hydraulic pump (hydraulic pump) 9,12 ... Oil supply pipe (piping) 10,13 ... Oil drain pipe (piping) 22 ... Motor casing 25 ... Valve casing 27 ... Cylinder 31 ... Output shaft 31a ... Eccentric cam part (conversion means) 32 ... Oil port (port) 33 ... Oil port (port) 35 ... Distribution valve 36 ... Valve oil passage (Valve liquid passage) 37 ... Valve oil passage (Valve liquid passage) 39, 40: drain escape means 41, 43 ... escape passage 42, 44 ... check valve 45 ... piston (conversion means) 46 ... connecting rod (conversion means)

Claims (1)

[Claims] 1. A motor casing, a valve casing connected to the casing, a distribution valve built in the valve casing with one end face facing the inside of the motor casing, the distribution valve being rotatably mounted on the motor casing and being distributed. An output shaft for interlocking a valve, a pair of ports provided in the valve casing, and a conversion built in the motor casing and for converting energy of hydraulic fluid supplied and discharged through the pair of ports into a rotational force of the output shaft. In the hydraulic motor having a means, a pair of drain relief means for releasing the hydraulic fluid leaked into the motor casing to the port on the low pressure side is provided in the valve casing, and these drain relief means are provided with the low pressure A relief passage communicating between the side port and the inside of the motor casing; And a check valve attached to the passage for allowing the hydraulic fluid to flow out from the inside of the motor casing to the low-pressure side port, and one of the drain relief means when the output shaft is rotating in one direction. A hydraulic motor, wherein the hydraulic motor is operably provided and the other drain relief means is operably provided when the output shaft is rotating in the other direction.