JPH1182280A - Oil-hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of cavitation in a hydraulic motor by supplying oil stored in the casing of the hydraulic motor to the cylinder side according to its necessity. SOLUTION: A hydraulic motor 21 is constituted of a casing 22, a rotating shaft 26, a rotor 27, respective pistons 29, a swash plate 31, a valve plate 32 and the like. Respective oil holes 34 are formed at the rotor 27, which communicate respective cylinder ports 28A with a drain oil chamber 25 in the casing 22. A check valve 35 which allows oil in the drain oil chamber 25 to circulate toward the cylinder 28 side and blocks flow in the reverse direction is formed on the way of the respective oil holes 34. It is thus possible to prevent the inside of any of the respective cylinders 28 of the rotor 27 from being kept in a negative pressure condition at the time of the inertia rotation of the hydraulic motor 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic motor used as an axial piston type hydraulic motor or a radial piston type hydraulic motor, for example, for rotating a vehicle such as a construction machine or an inertia body such as a drum for a rope winch. The present invention relates to a hydraulic motor suitably used.

[0002]

2. Description of the Related Art Generally, a construction machine such as a hydraulic crane includes a hydraulic motor for driving an inertial body and a pair of hydraulic motors for connecting the hydraulic motor to a hydraulic power source as described in Japanese Patent Application Laid-Open No. 60-168901. A control valve provided in the middle of the main pipeline, and a pair of control valves located between the control valve and the hydraulic motor and provided between the pair of main pipelines to relieve excess pressure generated in each main pipeline. An overload relief valve,
The pair of main fluid passages are provided between the control valve and the hydraulic motor and provided between the pair of main conduits to allow the oil liquid in the tank to flow toward each of the main conduits, and to prevent reverse flow. A hydraulic motor drive circuit including a check valve for makeup is provided.

In this type of conventional hydraulic motor drive circuit, when an operator switches a control valve from a neutral position in order to drive an inertial body by the hydraulic motor, hydraulic oil from a hydraulic source is supplied to the hydraulic motor. The hydraulic oil is discharged and the hydraulic motor is rotationally driven with the inertial body by the pressure oil at this time.

In this state, when the control valve is returned to the neutral position in order to stop the inertial body, the supply of the hydraulic oil to the hydraulic motor is stopped, but the hydraulic motor is temporarily inertially rotated by the inertial body. Become so. And
At the time of the inertial rotation, the hydraulic motor performs a pumping operation, and the hydraulic fluid sucked from one of the main lines (low-pressure side main line) out of the pair of main lines cut off from the hydraulic source by the control valve at the neutral position is used for the other. , A brake pressure is generated in the high-pressure side main line.

During this time, when the pressure in the low-pressure side main line becomes negative due to the suction operation of the oil by the hydraulic motor, the check valve for make-up is opened and the hydraulic oil in the tank is supplied to the low-pressure side main line. Cavitation or the like is suppressed by maintaining the inside of the low-pressure side main pipeline in a positive pressure state. When the brake pressure rises to the relief set pressure of the overload relief valve, the relief valve is opened and excess pressure (brake pressure) generated in the high pressure side main line is sent to the low pressure side main line or the tank side. And relief.

[0006]

By the way, in the above-mentioned prior art, each overload relief valve and each check valve for make-up are provided between a pair of main lines connected to the hydraulic motor, and the inertia rotation of the hydraulic motor is provided. Sometimes, when the pressure in the low-pressure main line becomes negative, the check valve for makeup opens to supply hydraulic oil and the like in the tank to the low-pressure main line. Such troubles may occur.

That is, for example, when the drum of the rope winch is driven to rotate by a hydraulic motor, the unwinding speed of the rope by the rope winch is 140 to 200 m.
If the rope winch is suddenly stopped with the speed being increased to about / min, sufficient oil liquid cannot be replenished into the low-pressure side main line even when the overload relief valve and the check valve for makeup are opened. In some cases, cavitation is likely to occur in the low-pressure main pipe.

In particular, inside a hydraulic motor having a large pipeline resistance, cavitation may occur due to negative pressure in, for example, each cylinder of the rotor, which not only deteriorates the durability and life of the hydraulic motor but also causes the worst case. In such a case, there is a problem that the inertial body may run away.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention is to replenish the cylinder side with an oil liquid (drain oil) normally contained in a casing of a hydraulic motor as necessary. Accordingly, it is an object of the present invention to provide a hydraulic motor capable of reliably preventing cavitation in the motor, extending the life and improving reliability.

[0010]

In order to solve the above-mentioned problems, a casing having a drain oil chamber formed therein, a rotating shaft rotatably provided in the casing, and a rotating shaft for rotating the rotating shaft are provided. A rotor rotatably provided in the casing, a plurality of cylinders having a cylinder port bored in an axial direction or a radial direction of the rotor, and slidably inserted into each of the cylinders; A plurality of pistons that generate rotational force on the rotor by pressure oil supplied and discharged into each cylinder, and are provided on the casing so as to be in sliding contact with the rotor, and pressurized oil is supplied into each cylinder via a cylinder port. The present invention is applied to a hydraulic motor including a valve member having a pair of supply and discharge ports for supplying and discharging.

A feature of the structure adopted in the first aspect of the present invention is that at least one of the rotor and the valve member is supplied with the oil liquid contained in the drain oil chamber of the casing into each of the cylinders. And a check valve is provided in the middle of the supply path to allow the oil liquid in the drain oil chamber to flow toward the cylinder side and to prevent a reverse flow. is there.

According to the above configuration, when any one of the cylinders of the rotor has a negative pressure tendency during the inertial rotation of the hydraulic motor, the check valve automatically opens, so that the hydraulic fluid in the casing is opened. Is allowed to flow (supply) into the cylinder via the supply path, and the inside of each cylinder of the rotor can always be maintained in a positive pressure state.

Further, in the invention according to claim 2, the supply passage is constituted by a plurality of oil holes formed in the rotor so that the cylinder port of each cylinder communicates with the drain oil chamber, and the check valve is provided in each of the oil holes. And are provided in the rotor respectively.

Thus, each cylinder port formed in the rotor can be communicated with the drain oil chamber in the casing via each oil hole and each check valve.

On the other hand, in the invention according to claim 3, the supply passage is constituted by an oil passage provided in a valve member so that at least one of the supply / discharge ports communicates with the drain oil chamber. It is configured to be provided in the middle of the oil passage.

Thus, the supply / discharge port on the low pressure side during the inertial rotation of the hydraulic motor can communicate with the drain oil chamber in the casing via the oil passage and the check valve.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hydraulic motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 to 4 show an example in which the hydraulic motor according to the first embodiment of the present invention is applied to a drive circuit for a rope winch.

In FIG. 1, reference numeral 1 denotes a hydraulic pump which constitutes a hydraulic source together with a tank 2. This hydraulic pump 1 is provided in a machine room such as a hydraulic crane and is driven to rotate by a prime mover (neither is shown). Thereby, the hydraulic fluid (oil liquid) in the tank 2 is discharged into the center bypass pipe 3.

Reference numeral 4 designates a control valve for a rope winch provided in the middle of the center bypass line 3. The control valve 4 is constituted by a hydraulic pilot type directional switching valve having, for example, 6 ports and 3 positions, and its inflow port is controlled. An upstream side of the valve 4 is connected to a pump line 5A branched from the center bypass line 3, and an outlet port is connected to the tank 2 via a tank line 5B. Each outflow / inflow port side of the control valve 4 is connected to a hydraulic motor 21 described later via a pair of main pipelines 6A and 6B. When the control valve 4 is switched from the neutral position (a) to the left and right switching positions (b) and (c), the main lines 6A and 6B are selectively switched to the pump line 5A and the tank line 5B. What is connected.

Reference numeral 7 denotes a hydraulic pilot type operation valve for switching the control valve 4. This operation valve 7 is a pressure reducing valve type pilot valve, the pump port side of which is connected to a pilot pump 8, and the tank port side of which is connected to the tank 2. It is connected. The operation valve 7 is connected at its output port side to the hydraulic pilot portions 4A, 4B of the control valve 4 via the pilot lines 9A, 9B, respectively.
When the tilting operation is performed in the direction, the pilot pressure corresponding to the tilting operation amount is generated in the pilot pipelines 9A and 9B, so that the control valve 4 is moved from the neutral position (A) to the left with a stroke amount corresponding to the pilot pressure. , Right switching positions (b) and (c).

10A and 10B are a control valve 4 and a hydraulic motor 2
1 and a pair of overload relief valves provided between the main pipelines 6A and 6B. The overload relief valves 10A and 10B cause the pressure in the main pipelines 6A and 6B to exceed the set relief pressure. When the valve is opened, the excess pressure at this time is transmitted to the common line 11 and check valves 12A, 1
It is configured to be relieved to the main pipelines 6B and 6A of the other party or the tank 2 side via 2B or the like.

12A and 12B are a control valve 4 and a hydraulic motor 2
1 is a pair of make-up check valves provided between the main pipelines 6A and 6B and between the main pipelines 6A and 6B. These check valves 12A and 12B are connected from the common pipeline 11 (tank 2) side to the main pipelines 6A and 6B. The configuration allows the hydraulic oil (oil liquid) to flow toward the 6B side and prevents the flow in the opposite direction. When the pressure in the main pipelines 6A, 6B becomes lower than the common pipeline 11 (tank 2) side, the check valves 12A,
The valve 12B is opened, and the oil liquid on the common pipeline 11 (tank 2) side is supplied into the main pipelines 6A and 6B.

Reference numeral 13 denotes a drain pipe provided in the hydraulic motor 21. The drain pipe 13 has one end connected to a drain hole 23C of a casing body 23 described later, and the other end connected to the tank 2. Reference numeral 14 denotes a main relief valve provided on the discharge side of the hydraulic pump 1. The relief valve 14 sets the maximum discharge pressure of the hydraulic pump 1 and releases an excess pressure higher than that to the tank 2.

Reference numeral 20 denotes a rope winch drum serving as an inertial body, 21 denotes a hydraulic motor for rotating the drum 20, and the hydraulic motor 21 is a fixed displacement type swash plate type hydraulic motor as shown in FIG. , A rotating shaft 26, a rotor 27, each piston 29, a swash plate 31, a valve plate 32, and the like. The rotary shaft 26 of the hydraulic motor 21 is connected to the drum 20 via a planetary gear reduction device (not shown) or the like, and rotates the drum 20 in directions indicated by arrows C and D in FIG.

That is, when the drum 20 of the rope winch is rotated in the direction of arrow C, the wire rope is unwound from the drum 20 together with a suspended load (not shown) or the like, whereby the suspended load is suspended downward. Can be lowered. When the rope winch drum 20 is rotated in the direction of arrow D,
The rope is wound around the drum 20, whereby the suspended load is lifted upward.

Reference numeral 22 denotes a casing of the hydraulic motor 21. As shown in FIG.
3B and a casing body 23 formed into a bottomed cylindrical shape
And a lid 24 covering the opening end side of the cylindrical portion 23B. The lid 24 forms a drain oil chamber 25 between itself and the casing body 23. A drain hole 23C is formed in the cylindrical portion 23B of the casing main body 23, and the drain hole 23C is formed.
Is connected to the tank 2 via a drain line 13.

Reference numeral 26 denotes a rotary shaft rotatably provided on the casing 22. Reference numeral 27 denotes a rotor for driving the rotary shaft 26. The rotor 27 is spline-coupled to the outer peripheral side of the rotary shaft 26. It rotates integrally with the rotating shaft 26 around the rotating shaft 26 in 23B. The rotor 27 has one end face facing the swash plate 31 and the other end face slidingly contacting the surface of the valve plate 32.

Are a plurality of cylinders formed in the rotor 27. The cylinders 28 are spaced apart from each other at regular intervals around the rotation shaft 26 in the circumferential direction of the rotor 27. Extends to. Here, the distal end side of each cylinder 28 opens at one end side end surface of the rotor 27,
Each cylinder port 28A is formed on the base end side so as to communicate with supply / discharge ports 32A and 32B described later.

Reference numerals 29, 29,... Denote a plurality of pistons slidably inserted in the respective cylinders 28.
Reference numeral 9 denotes a cylinder which is pushed toward the swash plate 31 by pressure oil supplied and discharged into and out of each cylinder 28 via a cylinder port 28A, and generates a rotational force on the rotor 27 by a hydraulic reaction force at this time. Also, shoes 30, 30,... Are respectively mounted on the projecting end sides of the pistons 29 projecting from the cylinders 28 so as to be swingable, and the shoes 30 slide on the swash plate 31 in a circular orbit. It is.

Here, each cylinder 28 and each piston 29
A small gap (not shown) is formed between the cylinders 28 to improve the sliding characteristics of each piston 29, and a part of the pressure oil supplied into each cylinder 28 is supplied to the casing through the small gap. 22 leaks into the drain oil chamber 25. Then, the drain oil chamber 25 in the casing 22 is filled with the oil liquid by the leaked oil, and the oil liquid overflowing from the drain oil chamber 25 is returned to the tank 2 via the drain pipe 13. .

Reference numeral 31 denotes a casing 2 located on the lid 24 side.
2, a swash plate 31 is fixedly provided on the lid 24 or the like, and the surface thereof is formed with a fixed inclination angle. Then, each shoe 30 slides along the inclined surface of the swash plate 31 to reciprocate each piston 29 in each cylinder 28 with a constant stroke.

Reference numeral 32 denotes a valve plate as a valve member fixedly provided on the bottom portion 23A side of the casing main body 23 so as to be in sliding contact with the other end surface of the rotor 27.
As shown in FIG. 5, a pair of supply / discharge ports 32A and 32B each having an eyebrow shape are formed. These supply / discharge ports 32A, 32B are connected to the respective cylinders 2 in the rotor 27.
8 through a cylinder port 28A to supply and discharge pressure oil from supply and discharge passages 33A and 33B described later into each cylinder 28.

Reference numerals 33A and 33B denote a pair of supply / discharge passages formed on the bottom portion 23A side of the casing body 23. The supply / discharge passages 33A and 33B constitute a part of the main pipelines 6A and 6B shown in FIG. The pressure oil supplied and discharged from the pump 1 via the main pipelines 6A and 6B is supplied to the supply and discharge ports 32A and 32B of the valve plate 32.
Through the cylinder 27 of the rotor 27.

.. Are oil supply holes formed in the radial direction of the rotor 27 as replenishment paths. As shown in FIG.
Radially extending toward the outer peripheral surface of
7 is open on the outer peripheral surface. The base end of each oil hole 34 is opened at the longitudinal middle portion of each cylinder port 28A, and each cylinder port 28A is configured to communicate with the drain oil chamber 25 in the casing 22.

Are check valves provided in the middle of each oil hole 34, and each check valve 35 is a valve body 35A which is detachably seated at a position in the middle of the oil hole 34 as shown in FIG. And the valve body 35
The valve body 35A is urged in the valve closing direction by centrifugal force due to the rotation of the rotor 27 and the spring force of the weak spring 35B. Each check valve 35 prevents the pressure oil supplied through the cylinder port 28A into each cylinder 28 from flowing toward each oil hole 34, and the high pressure in each cylinder 28 It is prevented from leaking to the drain oil chamber 25 side via.

When the pressure on the side of each cylinder 28 (cylinder port 28A) drops below the inside of the drain oil chamber 25 during the inertial rotation of the hydraulic motor 21 or the like, the valve body 35A of the check valve 35 causes the pressure difference between the two. The valve port is opened against the weak spring 35B, and the cylinder port 28A communicates with the outer peripheral surface of the rotor 27 through the oil hole 34. Thereby, the drain oil chamber 2
The oil liquid in 5 flows into the cylinder port 28A through the oil hole 34, and is supplied to the inside of the cylinder 28 or the like.

The drive circuit of the hydraulic motor 21 according to the present embodiment has the above-described configuration, and its operation will be described next.

First, when the operator tilts the operating lever 7A of the operating valve 7 in the direction indicated by the arrow A, a pilot pressure corresponding to the tilting operation amount is supplied from the operating valve 7 to the pilot line 9A side. The valve 4 is switched from the neutral position (a) to the switching position (b) with a stroke amount corresponding to the pilot pressure at this time. Thereby, the pressure oil from the hydraulic pump 1 is supplied from the main line 6A side to the supply / discharge passage 33A of the hydraulic motor 21 and the supply / discharge port 32A of the valve plate 32 shown in FIG.
Is supplied into each cylinder 28 of the rotor 27 through the

In the supply / discharge passage 33B of the hydraulic motor 21 and the supply / discharge port 32B of the valve plate 32, each cylinder 28
The return oil from inside is discharged, and this return oil is discharged to the tank 2 side via the main pipeline 6B shown in FIG.

Thus, the rotor 27 of the hydraulic motor 21 is
Is the pressure oil supplied and discharged into each cylinder 28 and each piston 29
, And the rotor 27 is rotationally driven together with the rotating shaft 26 by the hydraulic reaction force received by each piston 29 from the swash plate 31. The drum 20 of the rope winch connected to the protruding end side of the rotating shaft 26 via a planetary gear reduction device or the like is rotated together with the rotating shaft 26 in the direction of arrow C in FIG. The rope is unwound from the outer peripheral surface of the drum 20 so as to descend.

Next, when the operator returns the operation lever 7A to neutral to stop the movement of the suspended load in this state, the control valve 4 returns to the neutral position (A) and the hydraulic pump 1
From being supplied to the hydraulic motor 21 side. However, as described above, since the inertial force acts on the suspended load that is in the middle of descending, the hydraulic motor 21 is temporarily rotated by the drum 20 in the direction of arrow C by inertia.

During the inertial rotation, the hydraulic motor 2
When the control valve 4 performs the pumping operation, the oil liquid on one of the main lines 6A and 6B, which is disconnected from the hydraulic pump 1 and the tank 2 by the control valve 4, is supplied to the hydraulic motor 2 shown in FIG.
The air is sucked into each cylinder 28 of the rotor 27 through one supply / discharge passage 33A and the supply / discharge port 32A of the valve plate 32. The hydraulic fluid in each cylinder 28 is discharged toward the main pipeline 6B from the supply / discharge passage 33B of the hydraulic motor 21 and the supply / discharge port 32B of the valve plate 32.
By being enclosed in the main line 6B between the valve 1 and the control valve 4, a brake pressure is generated in the main line 6B.

During this time, when the pressure in the main line 6A on the low pressure side becomes negative due to the suction operation of the hydraulic fluid by the hydraulic motor 21, the check valve 12A for make-up is opened and the common line 1 is opened.
1 or the oil liquid in the tank 2 is supplied into the main line 6A on the low pressure side, and the occurrence of cavitation and the like is suppressed by maintaining the inside of the main line 6A in a positive pressure state.

On the high pressure side main line 6B, when the brake pressure rises to the relief set pressure of the overload relief valve 10B, the overload relief valve 10B opens and is generated in the high pressure side main line 6B. The excess pressure (brake pressure) is relieved to the low pressure side main line 6A or the tank 2 side.

The drum 2 is driven by the hydraulic motor 21.
0 is rotationally driven in the direction of arrow C, and the unwinding speed when unwinding the rope from the drum 20 is, for example, 140 to 2
In the case where the operation of lowering the suspended load (unwinding of the rope) is suddenly stopped at a speed of about 00 m / min or more, the overload relief valve 10B and the check valve 12A for makeup are opened. However, the main line 6 on the low pressure side
A may not be able to replenish sufficient oil liquid in A, and cavitation is likely to occur in the main pipeline 6A.

Therefore, in this embodiment, the hydraulic motor 2
One oil hole 34 is formed in the first rotor 27 so that each cylinder port 28A communicates with the drain oil chamber 25 in the hydraulic motor 21. In the middle of each oil hole 34, the oil liquid in the drain oil chamber 25 is A check valve 35 is provided to allow flow toward the side and prevent flow in the reverse direction.

As a result, even if any one of the cylinders 28 of the rotor 27 has a negative pressure tendency together with the low-pressure side main line 6A during the inertial rotation of the hydraulic motor 21, the check valve at this time. By automatically opening the valve 35, the oil liquid in the casing 22 (the drain oil chamber 25) is allowed to be supplied into the cylinder 28 via the oil hole 34 of the rotor 27, and each cylinder of the rotor 27 is 28
The inside can always be maintained at a positive pressure state, and the low pressure side main line 6A can also be maintained at a positive pressure state.

Therefore, according to the present embodiment, the oil liquid (drain oil) normally contained in the casing 22 of the hydraulic motor 21 is replenished to the cylinder 28 side as necessary, so that the hydraulic motor 21 Cavitation can be reliably prevented, the life of the rotor 27 and the valve plate 32 can be extended, the inertial rotation of the drum 20 and the like can be stably stopped, and the reliability can be improved.

Each oil hole 34 formed in the rotor 27
Is radially extended from the position of each cylinder port 28A toward the outer peripheral surface of the rotor 27, so that centrifugal force can be applied to the valve body 35A of each check valve 35 when the rotor 27 rotates. , Each valve body 35A is connected to a weak spring 35B.
In addition, it can be normally biased in the valve closing direction. Thereby, the spring force of the weak spring 35B can be reduced, and the situation where the valve body 35A of each check valve 35 is erroneously opened can be reliably prevented, and the opening and closing operations of each check valve 35 can be prevented. Can be stabilized.

On the other hand, the operating lever 7A of the operating valve 7 is tilted in the direction of arrow B in FIG. 1 to move the control valve 4 to the neutral position (a).
Is switched to the switching position (C), the hydraulic pump 1
Is supplied to the hydraulic motor 21 from the main pipeline 6B side, and the hydraulic motor 21 drives the drum 20 to rotate in the direction of arrow D, thereby moving the rope to the outer peripheral side of the drum 20 so as to raise the suspended load. The winding operation is performed.

Also, in this case, when the operation lever 7A is returned to the neutral position and the control valve 4 is returned to the neutral position (a), the hydraulic motor 21 may rotate with the drum 20 by inertia. The main line 6B which is on the low pressure side during the inertial rotation.
Oil can be replenished to the side through the check valve 12B, and when the pressure in each cylinder port 28A becomes lower than that in the drain oil chamber 25, the check valve 35 opens so that each cylinder 28 Drain oil chamber 25
The oil inside can be replenished.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. It shall be. However, a feature of the present embodiment is that the oil passages 41A and 41B as the supply passages are provided in the valve plate 32 and the oil passages 41A and 41B are provided.
The base end side of 41B communicates with the supply / discharge ports 32A, 32B, the front end side protrudes outward from the valve plate 32, and the check valves 42A, 42B are provided in the middle of the discharge portion. .

Here, the oil passages 41A and 41B are formed by a small-diameter metal pipe or the like, and a part thereof is provided in the supply / discharge port 32.
It is embedded in the valve plate 32 so as to extend toward the A, 32B side, and the remaining portion protrudes outward from the valve plate 32. The discharge ends of the oil passages 41A, 41B communicate with the drain oil chamber 25 in the casing 22, and the oil in the drain oil chamber 25 is supplied to the supply / discharge ports 32A, 32B by the check valve 4.
It is configured to allow replenishment via 2A and 42B.

Although the check valves 42A and 42B are substantially the same as the check valve 35 described in the first embodiment, the check valves 42A and 42B It is provided at an intermediate portion of the roads 41A and 41B. Therefore, it is only necessary to provide a part of the oil passages 41A and 41B in the valve plate 32, and it is possible to omit a complicated processing operation or the like for incorporating the check valve in the valve plate 32.

Thus, also in the present embodiment configured as described above, the oil passages 41A and 41
By providing the check valve B and the check valves 42A and 42B, substantially the same operation and effect as in the first embodiment can be obtained. Further, in the present embodiment, it is not necessary to provide each oil hole 34 and each check valve 35 in the rotor 27 as in the first embodiment, and the structure can be simplified.

FIG. 6 shows a third embodiment of the present invention, which is characterized in that the hydraulic motor is constituted by a variable displacement oblique shaft type hydraulic motor.
In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted.

In the drawing, reference numeral 51 denotes a diagonal axis type hydraulic motor according to the present embodiment, 52 denotes a casing of the hydraulic motor 51, and the casing 52 is formed on a cylindrical casing main body 53 and a head-side end face of the casing main body 53. And a fixed head casing 54. A drain oil chamber 55 is formed in the casing 52, and the drain oil chamber 55 is connected to the tank 2 via the drain hole 53A and the drain pipe 13.

Reference numeral 56 denotes a rotary shaft rotatably provided on the casing main body 53 via a bearing or the like. A drive disk 56A is integrally formed at the base end of the rotary shaft 56, and the drive disk 56A is connected to the casing main body 53. It is rotatably arranged in 53. And the casing body 53
The drum 20 of a rope winch is connected to a tip end of a rotating shaft 56 protruding from the shaft via a speed reducer (not shown) or the like.

Reference numeral 57 denotes a rotor for rotating the rotating shaft 56. A center shaft 58 is provided at the center of the rotor 57, and the spherical projection 58A of the center shaft 58 can swing around the center of the drive disk 56A. It is connected to.

The rotor 57 has a plurality of cylinders 59.
(Only one is shown) is bored so as to extend in the axial direction, and the cylinders 59 are arranged at regular intervals around the center shaft 58 in the circumferential direction of the rotor 57. Each cylinder 59 is formed with a cylinder port 59A located on the bottom side of the rotor 57. Each cylinder port 59A communicates the inside of each cylinder 59 with each supply / discharge port of a valve plate 61 described later. .

Are pistons slidably inserted into the respective cylinders 59 of the rotor 57, and each of the pistons 60 is integrally formed with a spherical projection 60A on the protruding end side protruding from the cylinder 59. , Each piston 60 has a spherical projection 60
A is swingably connected to the drive disk 56A via A.

Reference numeral 61 denotes a valve plate as a valve member provided on the head casing 54 so as to be in sliding contact with the bottom end surface of the rotor 57. The valve plate 61 has a pair of eyebrow-shaped supply / discharge ports (both shown in FIG. (Not shown). And
Each of these supply / discharge ports also communicates with each cylinder 59 in the rotor 57 via the cylinder port 59A in substantially the same manner as the supply / discharge ports 32A, 32B described in the first embodiment, and is connected to each cylinder 59. It is configured to supply and discharge pressure oil.

Reference numeral 62 denotes an oil hole (only one is shown) serving as a supply path formed in the radial direction of the rotor 57, and extends radially from the position of each oil port 62 to each cylinder port 59A toward the outer peripheral surface of the rotor 57. The tip side is open to the outer peripheral surface of the rotor 57. Each of the oil holes 62 has a base end side opening at an intermediate portion in the longitudinal direction of each of the cylinder ports 59A, so that each of the cylinder ports 59A communicates with the drain oil chamber 55 in the casing 52.

Reference numeral 63 denotes a check valve provided in the middle of each oil hole 62. Each check valve 63 has the same configuration as the check valve 35 described in the first embodiment, and includes a drain oil chamber 55. This allows the oil liquid inside to be replenished (distributed) toward the cylinder port 59A side. Each check valve 63 prevents the pressure oil supplied through the cylinder port 59A into each cylinder 59 from flowing toward each oil hole 62, and the high pressure in each cylinder 59 is applied to each oil hole. Leakage to the drain oil chamber 25 side via 62 is prevented.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as in the first embodiment can be obtained.

In the third embodiment, the check valve 63 is provided on the rotor 57 together with the oil holes 62. However, instead of this, the rotor 57 is replaced with a check valve substantially in the same manner as in the second embodiment. For example, the valve plate 61 may be provided with a check valve together with an oil path as a supply path.

On the other hand, in the second embodiment, the valve plate 3
2 has been described as providing oil passages 41A and 41B made of a metal pipe or the like, but the present invention is not limited to this. For example, as shown by an imaginary line in FIG. Oil passages 51A and 51B are formed.
The check valves 52A and 52B may be provided in the middle of the first valve 51B. And even in this case, the check valve 52A,
52B can be configured in substantially the same manner as the check valve 35 described in the first embodiment.

In the first and second embodiments, the rope winch drum 20 unwinds the rope when the rotary shaft 26 (rotor 27) of the hydraulic motor 21 rotates in the direction of arrow C. Then, when rotating in the direction of arrow D, the winding operation of the rope is performed. Since the speed at the time of inertia rotation is usually higher at the time of unwinding than at the time of winding of the rope, the hydraulic motor 21 has a negative pressure in the hydraulic motor 21 at the time of unwinding rather than at the time of rope winding. It tends to tend.

Therefore, the oil passages 41A, 41B
(51A, 51B) and check valves 42A, 42B (52A,
52B), for example, the oil passage 41B (51B) and the check valve 42B (52B) are not necessarily provided, and may be omitted in some cases, and the oil passage 41A (5
1A) and only the check valve 42A (52A) may be provided on the valve plate 32.

Further, in the first and second embodiments,
The case where the hydraulic motor 21 is constituted by a fixed displacement type swash plate type hydraulic motor will be described as an example, and in the third embodiment, the description will be made assuming that the hydraulic motor 51 is constituted by a variable displacement type inclined shaft type hydraulic motor. However, the present invention is not limited to this, and may be applied to, for example, a variable displacement swash plate type hydraulic motor or a fixed displacement type swash shaft type hydraulic motor.

The present invention can also be applied to, for example, a radial piston type hydraulic motor in which a plurality of cylinders are formed in the radial direction of the rotor with the rotation axis as the center. The oil holes may be formed in the rotor as supply channels so as to communicate with the drain oil chamber in the casing, and a check valve may be provided in the middle of each oil hole.

Further, in each of the above embodiments, the hydraulic motor drive circuit for the rope winch has been described as an example. However, the present invention is not limited to this. For example, a drive circuit for a swing motor or a drive motor for a travel motor is provided. It can be applied to circuits and the like.

[0074]

As described in detail above, according to the first aspect of the present invention, at least one of the rotor and the valve member is supplied with the oil liquid contained in the drain oil chamber of the casing into each cylinder. Since a supply path is provided in the supply path to allow the oil liquid in the drain oil chamber to flow toward the cylinder side, and a check valve for preventing the reverse flow is provided in the supply path, When the pressure in any one of the cylinders of the rotor becomes negative during the inertial rotation of the hydraulic motor, the check valve is automatically opened, and the oil in the casing is supplied to the cylinder via the supply path. And the inside of each cylinder of the rotor can always be maintained in a positive pressure state. Therefore, the occurrence of cavitation in the hydraulic motor can be reliably prevented, the life of the rotor and the valve member can be extended, the inertial rotation of the inertial body can be stably stopped, and the reliability can be improved. .

According to the second aspect of the present invention, each cylinder port formed in the rotor communicates with the drain oil chamber in the casing through each oil hole, and a check valve is provided in the middle of each oil hole. With the configuration, when any one of the cylinders of the rotor has a negative pressure tendency during the inertial rotation of the hydraulic motor, the check valve is automatically opened to release the oil liquid in the casing. The cylinder can be replenished through the oil hole, and the inside of each cylinder of the rotor can always be maintained at a positive pressure.

On the other hand, according to the third aspect of the present invention, a replenishing passage is constituted by an oil passage provided in the valve member such that at least one of the supply / discharge ports communicates with the drain oil chamber. The check valve is automatically opened even if the supply / discharge port, which is on the low pressure side during the inertial rotation of the hydraulic motor, becomes negative pressure together with the cylinder in the rotor. The oil liquid in the casing can be supplied to the supply / discharge port and the cylinder on the low pressure side through each oil hole, and the supply / discharge port and the inside of the cylinder can always be maintained in a positive pressure state.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a drive circuit of a hydraulic motor according to a first embodiment.

FIG. 2 is a longitudinal sectional view showing a swash plate type hydraulic motor according to the first embodiment.

FIG. 3 is an enlarged view of a main part of the hydraulic motor shown in FIG. 2;

FIG. 4 is an enlarged cross-sectional view showing a valve plate and the like as viewed from the direction of arrows IV-IV in FIG. 2;

FIG. 5 is an enlarged sectional view of the same position as FIG. 4 showing a valve plate and the like of a hydraulic motor according to a second embodiment.

FIG. 6 is a longitudinal sectional view showing a diagonal axis type hydraulic motor according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump (hydraulic power source) 4 Control valve 6A, 6B Main line 7 Operating valve 10A, 10B Overload relief valve 12A, 12B Makeup check valve 20 Drum (inertial body) 21, 51 Hydraulic motor 22, 52 Casing 25 , 55 Drain oil chamber 26, 56 Rotating shaft 27, 57 Rotor 28, 59 Cylinder 28A, 59A Cylinder port 29, 60 Piston 31 Swash plate 32, 61 Valve plate (valve member) 34, 62 Oil hole (supply path) 35, 42A, 42B, 52A, 52B, 63 Check valve 41A, 41B, 51A, 51B Oil passage (supply passage)

Claims (3)

[Claims] A casing forming a drain oil chamber therein; a rotating shaft rotatably provided in the casing;
A rotor rotatably provided in the casing to rotationally drive the rotating shaft, a plurality of cylinders having a cylinder port drilled in an axial or radial direction of the rotor, and sliding inside each of the cylinders; A plurality of pistons that are movably inserted and generate rotational force on the rotor by pressure oil supplied and discharged into and from the respective cylinders, and are provided on the casing so as to be in sliding contact with the rotor. In a hydraulic motor comprising a valve member having a pair of supply / discharge ports for supplying / discharging pressure oil via a cylinder port, at least one of the rotor and the valve member is housed in a drain oil chamber of the casing. A supply path for supplying the supplied oil liquid into each of the cylinders, and in the middle of the supply path, the oil liquid in the drain oil chamber flows toward the cylinder side. A hydraulic motor characterized in that it is provided with a check valve for allowing flow in the opposite direction. 2. The replenishing passage is constituted by a plurality of oil holes formed in the rotor so that a cylinder port of each cylinder communicates with the drain oil chamber, and the check valve is located in the middle of each oil hole. The hydraulic motor according to claim 1, wherein the hydraulic motor is configured to be provided in each of the rotors. 3. The supply passage is constituted by an oil passage provided in the valve member such that at least one of the supply / discharge ports communicates with the drain oil chamber, and the check valve is provided in the oil passage. 2. The hydraulic motor according to claim 1, wherein the hydraulic motor is provided in the middle of the hydraulic motor.