JP2000205103A - Piston motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston motor equipped with a brake retarding device of simple structure. SOLUTION: A brake piston 50 presses a casing side brake disc 52 and a cylinder block side brake disc 51 using the spring force of a spring member 54 so that the cylinder block stops rotating. An oil pressure chamber 53 is formed between the brake piston 50 and casing body 33, and to this chamber 53 the working oil from the pressure port 65 of a brake retarding device 60 is introduced to displace the brake piston 50 toward the other side. A first oil passage 74 is formed between the pressure port 65 and chamber 53, while a second oil passage 75 formed in a plunger 71 is in communication with the first oil passage 74 and a third oil passage 76 leading to inside the casing 31. A ball check valve 80 is installed in the connection part of the first oil passage 74 with the second 75, and the second oil passage 75 is equipped with a multi- stage throttle 85.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydraulic piston motor used in construction machines and the like.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing the structure of a typical conventional piston motor, which is disclosed in Japanese Patent Application Laid-Open No. 7-208319. Piston motor 1 is casing 3
The rotary shaft 2 is rotatably supported on the rotary shaft 2, and the rotary shaft 2 is provided with a cylinder block 4 that rotates together with the rotary shaft 2 in the casing 3. A plurality of cylinder block-side brake disks 5 are provided on the outer peripheral portion of the cylinder block 4, and a plurality of casing-side brake disks 6 interposed between the cylinder block-side brake disks 5 are provided on the casing 3. The cylinder block-side brake disk 5 is displaceable in the axial direction of the rotary shaft 2 and is mounted on the cylinder block 4 in a state where rotation around the axis is prevented. Similarly, the casing-side brake disk 6 is also displaceable in the axial direction. And attached to the casing 3 in a state where displacement around the axis is prevented.

An annular brake piston 7 is supported by the casing 3 between the end wall 9 of the left casing 3 in FIG. 4 and the casing-side brake disc 6 so as to be axially displaceable. A spring member 8 for biasing the brake piston 7 in one axial direction (rightward in FIG. 4) is interposed between the wall 9 and the wall 9. The brake piston 7 and the casing 3 opposite to the spring member 8
And a hydraulic chamber 11 is formed between the hydraulic chamber 11 and the brake piston 7 is displaced to the other side in the axial direction against the spring force of the spring member 8 in a state where hydraulic oil having a predetermined pressure or more acts on the hydraulic chamber 11. Then, the casing side brake disk 6 and the cylinder block side brake disk 5 are separated from each other, and the rotating shaft 2 is rotatable. Therefore, the hydraulic chamber 1 of the piston motor 1 is moved from the main pump (not shown).
In addition to supplying hydraulic oil to the piston motor 1 to actuate pressure oil, the main pump supplies hydraulic oil to the piston motor 1 to drive the piston motor 1 to rotate.

When the piston motor 1 is stopped, a switching valve (not shown) provided in a supply / discharge path for supplying hydraulic oil to the piston motor 1 is switched to a neutral position to close the supply / discharge path to close the hydraulic oil. Stop supplying. At this time, a braking force is acted on by a hydraulic pressure generated in the discharge path, whereby the piston motor 11 is decelerated and stopped.

[0005] Since an inertia body (not shown) is connected to the output shaft 2 of the piston motor 1, a high braking pressure is generated in the discharge path of the piston motor 1 when the piston motor 1 is stopped. A valve (not shown) is provided, and the upper limit of the braking pressure is limited by operating the relief valve. Accordingly, the relief valve is operated, the inertial energy is converted into heat while the inertial body rotates together with the rotating shaft 2 against the braking pressure, the rotation is reduced, the relief valve closes, and the rotation stops soon. Will be.

After the rotation is stopped in this way, the hydraulic oil is discharged from the hydraulic chamber 11 and the brake piston 7 is displaced to one side in the axial direction by the spring return force of the spring member 8 to move the casing-side brake disk 6 to the cylinder. The rotating shaft 2 is fixed by the frictional force between the casing side brake disk 6 and the cylinder block side brake disk 5 by being pressed against the block side brake disk 5.

[0007] In addition to switching the switching valve, the parking brake further using the brake disks 5 and 6 is operated because the hydraulic device has some oil leakage, and the inertial body is kept in a fixed position for a long time. This is because it is difficult to maintain As an example, when the piston motor 1 is used in a traveling device of a hydraulic shovel, the load on the piston motor 1 caused by the weight of the hydraulic shovel when the hydraulic shovel is stopped on a slope, even though the switching valve is in the neutral position. Hydraulic oil leaks over time,
The hydraulic excavator goes down the slope. In order to prevent such a problem, the above-described parking brake is provided.

To stop the piston motor 1 in this manner, the switching valve is switched to the neutral position to stop the supply of hydraulic oil to the piston motor 1 and to stop the supply of hydraulic oil to the hydraulic chamber 11. As described above, the braking operation is performed, but immediately after switching the switching valve, the rotation of the inertial body is decelerated by the braking pressure, and after sufficiently decelerating, it is necessary to operate the parking brake using the brake disks 5 and 6. . Therefore, when the switching valve is switched to stop the piston motor 1, the piston motor 1 slowly releases the hydraulic oil in the hydraulic chamber 11 to delay the parking brake.
Is provided.

FIG. 5 is an enlarged sectional view showing the vicinity of the brake delay device 10. As shown in FIG. The brake delay device 10 is provided integrally with the casing 3 and has a pressure port 12 through which hydraulic oil having a predetermined pressure or more is supplied, a first oil passage 13 communicating the pressure port 12 with the hydraulic chamber 11, and The first oil passage 13 is provided with a spool 15 perpendicular to the first oil passage 13. The spool 15 is supported in the spool hole 16 so as to be vertically displaceable in FIG. 5 and is urged upward by a spool spring 23. Above the spool 15, a signal pressure port 14 opening to the spool 15 is formed. When a signal pressure is applied to the signal pressure port 14, the spool 15 is displaced downward against a spring force. In this state, the spool 15 is in the first position.
The oil passage 13 communicates with the pressure port 12 and the hydraulic chamber 11. When the signal pressure decreases, the spool 15 is displaced upward by the spring return force, and the spool 15 is in a communication state with the first oil passage 13. Cut off.

Further, an orifice spool 20 is provided in the first oil passage 13 between the spool 15 and the hydraulic chamber 11. The orifice spool 20 has an orifice 27 at the upper end, is supported so as to be vertically displaceable in an orifice spool hole 24, and is urged upward by an orifice spring 22. Orifice spool hole 24 and spool hole 16
A second oil passage 21 that connects these is formed between
A through hole 26 is formed in a side portion of the orifice spool 20, and this through hole 26 communicates with the second oil passage 21 when the orifice spool 26 is displaced upward. The spool hole 16 communicates with a third oil passage 25 communicating with the inside of the casing.

When the signal pressure is input to the signal pressure port 14 and the hydraulic oil having a pressure equal to or higher than the predetermined pressure is supplied to the pressure port 12, the operation of the hydraulic chamber 11 through the first oil passage 13 is performed to the hydraulic chamber 11. The oil acts on the brake piston 7
Is displaced to the other side in the axial direction against the spring force of the spring member 8, and the rotating shaft 2 is rotatable.

When the rotating shaft 2 is fixed, the hydraulic oil acting on the signal pressure port 14 is shut off and the spool 15 is displaced upward. Then, from the pressure port 12 to the hydraulic chamber 11
As a result, the hydraulic oil acting on the hydraulic cylinder 11 is interrupted, and the brake piston 7 starts to be displaced to one side in the axial direction by the spring force of the spring member 8, so that the pressure in the hydraulic chamber 11 and the first oil passage 13 increases.
Then, the hydraulic oil in the first oil passage 13 flows into the orifice spool hole 24 via the orifice 27 formed at the upper end of the orifice spool 20, and the pressure in the first oil passage 13 and the pressure in the orifice spool hole 24. Are equal, the orifice spool 20 is displaced upward by the spring force of the spring 22. As a result, the through hole 26 of the orifice spool 20 communicates with the second oil passage 21, and the hydraulic oil in the orifice spool hole 24 is supplied to the casing 3 via the second oil passage 21, the spool hole 16 and the third oil passage 25. Is discharged into As a result, the pressure in the orifice spool hole 24 decreases, and the pressure in the first oil passage 13 causes the orifice spool 20 to be displaced downward against the spring force of the spring 22.
Then, the hydraulic oil in the first oil passage 13 flows into the orifice spool hole 24 again through the orifice 27 of the orifice spool 20. By repeating such an operation, the hydraulic oil in the hydraulic chamber 11 is gradually discharged and the brake piston 7
Can be slowly displaced to one side in the axial direction to delay the braking action.

[0013]

In the conventional brake delay device 10 for the piston motor 1 described above, the spool 15
The oil passage is switched by the orifice spool 20 and is resiliently supported by a spring 22 so as to be vertically displaceable with respect to the oil passage. The mechanism is a mechanism for slowly discharging the hydraulic oil in the chamber 11, and the structure is very complicated. Due to such a complicated structure, the configuration of the piston motor 1 is increased in size and weight.

An object of the present invention is to provide a piston motor having a brake delay device having a simple structure.

[0015]

According to a first aspect of the present invention, there is provided a rotary shaft, a casing for rotatably supporting the rotary shaft about its axis, and a cylinder block rotating with the rotary shaft in the casing. A brake piston provided in the casing so as to be displaceable along the axial direction of the rotating shaft; a spring member interposed between the brake piston and the casing to bias the brake piston toward one side in the axial direction; A hydraulic chamber is formed between the piston and the casing, and in a state where hydraulic oil having a predetermined pressure or more acts on the hydraulic chamber, the brake piston moves toward the other side in the axial direction against the spring force of the spring member. When the hydraulic oil acting on the hydraulic chamber is displaced below the predetermined pressure, the brake piston is moved by the spring return force of the spring member. In a piston motor that brakes a cylinder block by being displaced to one side in a linear direction, a pressure port through which hydraulic fluid is supplied to the casing, a first oil path that communicates the pressure port with the hydraulic chamber, and a first oil path A second oil passage for discharging the hydraulic oil in the hydraulic chamber is formed, and a connection between the first oil passage and the second oil passage allows a flow of the hydraulic oil from the pressure port to the hydraulic chamber. And a check valve for preventing a flow of hydraulic oil from the pressure chamber to the pressure port.

According to the present invention, in a state where hydraulic oil having a predetermined pressure or more acts on the pressure chamber from the pressure port via the first oil passage, the brake piston is displaced to the other side in the axial direction, and the rotating shaft is rotated. It is rotatable. When stopping the rotation of the rotating shaft, the hydraulic oil supplied to the pressure port is shut off. Then, the pressure of the hydraulic oil acting on the pressure chamber becomes lower than the predetermined pressure, and the brake piston starts to be displaced to one side in the axial direction by the spring return force of the spring member. The hydraulic oil starts to drain through. The connection between the first oil passage and the second oil passage is provided with a check valve that allows the flow of hydraulic oil from the pressure section to the hydraulic chamber and prevents the flow of hydraulic oil from the pressure chamber to the pressure port. The hydraulic oil discharged from the hydraulic chamber is discharged via the second oil passage. By discharging the hydraulic oil in the hydraulic chamber in this way, the brake piston is displaced to one side in the axial direction by the spring force, and the rotation of the rotating shaft can be fixed by applying the brake force. In the above-described prior art, the structure is complicated because the flow path is switched by using the spool and the orifice spool to discharge the hydraulic oil in the hydraulic chamber. However, in the present invention, the check valve is connected to the first valve as described above. Since the flow path is switched by providing the connection portion between the oil passage and the second oil passage, the structure can be simplified. Thereby, the configuration of the piston motor can be reduced in size and the weight can be reduced.

According to a second aspect of the present invention, a multistage throttle is interposed in the second oil passage.

According to the present invention, since the multi-stage throttle is interposed in the second oil passage, when the hydraulic oil in the hydraulic chamber is discharged through the second oil passage, it is slowly discharged through the multi-stage throttle. You. This allows the brake to be delayed while the inertial body stops. By interposing the check valve and the multi-stage throttle in the second oil passage in this way, it is possible to have an inline structure, so that the configuration can be greatly simplified as compared with the related art.

Although a configuration in which a choke is interposed instead of the multistage throttle is also conceivable, the flow resistance of the choke largely depends on the viscosity of the hydraulic oil. That is, the delay time of the brake greatly varies depending on the temperature of the hydraulic oil. On the other hand, by using a multi-stage orifice throttle as in the present invention, the brake delay time can be made substantially constant regardless of the temperature of the hydraulic oil.

[0020]

FIG. 1 is a sectional view showing the structure of a piston motor 30 according to an embodiment of the present invention. The piston motor 30 includes a rotating shaft 32, a casing 31 that rotatably supports the rotating shaft 32 around its axis, and a cylinder block 40 that is housed in the casing 31 and rotates with the rotating shaft 32. The casing 31 is
Casing body 33 that houses cylinder block 40
And an end wall 34 for preventing the opening of the casing body 33. Bearing 35 and end wall 3 provided on casing body 33 in one axial direction of rotating shaft 32 (right side in FIG. 1)
The rotary shaft 32 is rotatably supported by the casing 31 by a bearing 36 provided on the casing 4. Cylinder block 40
A plurality of pistons 41 are accommodated so as to be displaceable in the axial direction, and are connected to the rotating shaft 32 in a state where displacement around the axis is prevented with respect to the rotating shaft 32 by spline coupling. A swash plate 42 inclined with respect to the axis is provided on the casing body 33, and a shoe that is rotatably connected to the piston 41 at the tip of each piston 41 and slides on one surface of the swash plate 42. 43 are connected. Casing 31
A hydraulic oil supply port 44 to which hydraulic oil for rotating the piston motor 30 is supplied is formed in the end wall 34, and a pair of semicircular arcs is formed between the cylinder block 40 and the end wall 34. A valve plate 45 having a valve hole is interposed.

Therefore, the hydraulic oil supply port 44 connects the valve plate 4
For example, when hydraulic oil is supplied to the piston insertion hole 49 of the cylinder block 40 at the back side in the paper plane of FIG. 1 through the respective pistons 5, the respective pistons 41 extend and rotate while the shoes 43 slide on the swash plate 42. The shaft 32 is driven to rotate counterclockwise when viewed from the right in FIG. Further, each piston 41 disposed on the near side with respect to the paper surface of FIG. 1 is contracted while being guided on the swash plate 42 and discharges the oil in the piston insertion hole 49. Is discharged from a discharge port (not shown) formed at the bottom. Thus, the rotating shaft 32 is driven to rotate.

On the outer periphery of the cylinder block 40, a plurality of annular cylinder block side brake discs 51 are provided.
In this embodiment, three sheets are provided. Between the cylinder block side brake disks 51, three annular casing side brake disks 52 connected to the casing 31 are provided. Each brake disk 51 on the cylinder block side is connected to the cylinder block 40 in a state where the brake disk 51 can be displaced in the axial direction of the rotation shaft and the displacement around the axis is prevented. Similarly, the casing-side brake disc 52 is connected to the casing main body 33 in a state where the displacement in the axial direction is possible with respect to the casing main body 33 and the displacement around the axis is prevented.

The casing body 33 includes a casing-side brake disk 52 on the other side in the axial direction and an end wall 34.
An annular brake piston 50 is provided so as to be displaceable in the axial direction. The brake piston 50 has a small-diameter portion 57 and a large-diameter portion 58 connected in the axial direction and has a stepped cross section. One end 55 on one side in the axial direction of the small diameter portion 57 disposed on one side in the axial direction faces the casing side brake disk 52. A spring member 54 is interposed between the other end 56 of the small diameter portion 57 and the end wall 34. The spring member 54 includes a plurality of compression coil springs, and urges the brake piston 50 toward one side in the axial direction. Small diameter portion 57 of brake piston 50
An annular hydraulic chamber 53 is formed between the stepped portion between the main body and the large diameter portion 58 and the casing main body 33. This hydraulic chamber 53
In a state where hydraulic oil having a predetermined pressure or more acts on the brake piston 50, the brake piston 50 is displaced to the other side in the axial direction against the spring force of the spring member 54, and the respective casing-side brake disks 52 and the respective cylinder blocks are displaced. The rotation shaft 32 is rotatable with the side brake disk 51 separated from each other. A brake delay device 60 for slowly discharging the hydraulic oil in the hydraulic chamber 53 is provided integrally with the casing main body 33 at one side of the casing main body 33 (upper side in FIG. 1).

FIG. 2 is an enlarged sectional view showing the vicinity of the brake delay device 60. The step surface 61 between the outer peripheral surface 57a of the small diameter portion 57 of the brake piston 50 and the outer peripheral surface 58a of the large diameter portion 58 functions as a pressure receiving surface of the brake piston 50. The casing main body 33 is provided with an O-ring 62 slidably contacting the outer peripheral surface 57a of the small diameter portion 57, and similarly provided with an O-ring 63 slidably contacting the outer peripheral surface 58a of the large diameter portion 58. These O-rings 62, 68 prevent oil leakage from the hydraulic chamber 53.

The brake delay device 60 is provided with a pressure port 65 to which hydraulic oil having a pressure equal to or higher than the predetermined pressure is supplied, and a first oil passage 74 communicating from the pressure port 65 to the hydraulic chamber 53 is formed. A plunger hole 70 is formed in communication with the first oil passage 74 and parallel to the axial direction.
A plunger 71 is mounted in the plunger hole 70.
A second oil passage 75 extending in the axial direction of the plunger 71 and opening at the tip of the plunger 71 and facing the first oil passage 74 is formed. Second at the base end side of the plunger 71
The oil passage 75 opens laterally (downward in FIG. 2). A third oil passage 76 communicating with the internal space of the casing 31 and the plunger hole 70 is formed in the casing main body 33, and a second oil passage 75 on the second base end side formed in the plunger 71 is the third oil passage. It will communicate with 76.

The first oil passage 74 extends in parallel with the axial direction and communicates with the pressure port 65 on the pressure port side first oil passage 7.
2, and formed perpendicular to the first oil passage on the pressure port side,
And a first hydraulic passage 73 that communicates with the hydraulic chamber 53. The second oil passage 75 formed in the plunger 71 includes the first oil passage 72 on the pressure port side and the first oil passage 7 on the hydraulic chamber side.
The ball check valve 80 is provided at the connecting portion, which is opened and connected to the connecting portion with the connecting member 3.

The ball check valve 80 includes a ball 81 for closing the first oil passage 72 on the pressure port side, and a spring 82 for urging the ball 81 toward the first oil passage 72 on the pressure port side. Second oil passage 75 formed in plunger 71
Is formed with a large diameter so that the ball 81 can be inserted and removed.
A spring 82 made of a compression coil spring is inserted into the opening of the plunger 71, and the ball 81
When the oil passage 72 is closed, the plunger 70
Outside.

When a pressure higher than the predetermined pressure is supplied from the pressure port 65, the ball 81 retreats toward the plunger 71 against the spring force of the spring 82, and the pressure port 65 and the hydraulic chamber 53 communicate with each other. The brake piston 50 is displaced to the other axial side. The remaining hydraulic oil from the pressure port 65 is supplied to the casing 3 via the second oil passage 75 and the third oil passage 76.
1 and is returned to the tank. When the pressure of the hydraulic oil supplied to the pressure port 65 falls below the predetermined pressure, the brake piston 50
The hydraulic oil in the hydraulic chamber 53 is discharged by being displaced to one side due to the spring return force of. With the discharge of the hydraulic oil, the ball 81 quickly closes the pressure port side first oil passage 72 by the spring return force of the spring 82 of the ball check valve 80, and the hydraulic oil in the hydraulic chamber 53 and the hydraulic chamber side first oil passage 73. Is prevented from flowing out to the first oil passage 72 on the pressure port side, and the hydraulic oil in the first oil passage 73 on the hydraulic chamber side and the hydraulic oil in the hydraulic chamber 53 are surely removed from the second oil passage 7.
Flow into the 5 side.

The second oil passage 75 has a ball check valve 80
A multi-stage throttle 85 is interposed downstream of the spring 82. FIG. 3 is an enlarged sectional view showing the multi-stage aperture 85. The multi-stage diaphragm 85 has a plurality of orifices 86 formed in the center, and in the present embodiment, six disc-shaped plates 87.
And an annular spacer 88 interposed between the plates 87 to form a space between the plates 87. Such a multi-stage restrictor 85 is engaged with and attached to a step between the large-diameter portion and the small-diameter portion of the second oil passage 75. The flow rate of the hydraulic oil passing through the multistage throttle 85 is restricted by passing through the plurality of orifices 86, whereby the hydraulic oil discharged from the hydraulic chamber 53 is slowly discharged into the casing 31.

The second oil passage 75 formed in the plunger 71 has a multi-stage throttle 85 and a ball check valve 8.
The zero spring 82 is mounted to form an in-line structure. Therefore, when it is necessary to replace the ball check valve 80 or the multistage throttle 85, the plunger 71 can be detached to facilitate replacement. The adjustment of the multistage aperture 85 can be easily performed by adjusting the number of the plates 86 having the orifices 86 formed therein.

Next, the operation of the piston motor 30 during the braking action will be described. Hydraulic oil of a predetermined pressure or higher for driving the piston motor 30 from a main pump (not shown) is supplied to the hydraulic oil supply port 44,
It is also supplied to the pressure port 65 of the brake delay device 60. Hydraulic oil supply port 4 for main pump and piston motor
A switching valve is provided between the oil supply port 4 and the hydraulic oil supply port 4 when the piston motor 30 is stopped.
Cut off the supply of hydraulic oil to 4. When switching the switching valve,
In conjunction with this, the pressure port 65 of the brake delay device 60
The supply of the hydraulic oil supplied to is shut off. Pressure port 6
When the supply of the working oil to the hydraulic chamber 53 is cut off and the pressure of the working oil acting on the hydraulic chamber 53 becomes lower than the predetermined pressure, the brake piston 50 starts to be displaced to one side in the axial direction by the spring return force of the spring member 54. . As a result, the hydraulic oil in the hydraulic chamber 53 is discharged, and the first oil passage 72 on the pressure port side is closed by the ball check valve 80, so that the first hydraulic path on the hydraulic chamber 53 is closed.
The hydraulic oil in the oil passage 73 and the hydraulic chamber 53 is led to the second oil passage 75. The hydraulic oil guided to the second oil passage 75 is a multi-stage throttle 8
5, the flow rate is restricted and the casing 31 slowly
Is discharged into Therefore, the brake piston 50 is slowly displaced to one side in the axial direction. When one end portion 55 of the brake piston 50 presses the casing-side brake disc 52 disposed on the other side in the axial direction, the cylinder-block-side brake disc 51 is sandwiched between the casing-side brake discs 52, and the casing-side brake disc 52 and the cylinder block The cylinder block 40 is braked by the frictional force with the side brake disk 51. In this manner, the action of the parking brake is delayed until the inertial body stops by the slow displacement of the brake piston 50 to one side in the axial direction.

When the piston motor 30 is driven, the switching valve is switched to supply the working oil from the main pump to the working oil supply port 44. At this time, hydraulic oil is supplied from the main pump to the pressure port 65 of the brake delay device 60 in conjunction with the switching of the switching valve, and the brake piston 50
Is displaced to the other side in the axial direction to release the brake. Since the pressure port 65 and the hydraulic chamber 53 are communicated with each other via the first oil passage 74, the brake fixer 50 is quickly displaced to the other side in the axial direction to quickly release the brake.

The brake delay device of the present invention is not limited to the case where it is provided in the swash plate type piston motor described above, but may be provided in the swash plate type piston motor.

[0034]

According to the first aspect of the present invention, since the first oil passage is provided with the check valve, the first oil passage does not require a complicated structure as in the prior art, and is discharged from the hydraulic chamber with a simple structure. Operating oil can be switched to the second oil passage side.

According to the second aspect of the present invention, since the multi-stage throttle is interposed in the second oil passage, the orifice spool having a complicated structure as in the prior art is not required, and the oil is discharged from the hydraulic chamber. Thus, the brake piston can be displaced slowly by limiting the flow rate of the operating oil. Further, the check valve and the multistage throttle are configured in the second oil passage, so that the inline structure can be made extremely simple as compared with the conventional configuration.
By thus simplifying the structure, the weight of the piston motor can be reduced.

[Brief description of the drawings]

FIG. 1 shows a piston motor 3 according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a structure of No. 0.

FIG. 2 is an enlarged sectional view showing the vicinity of a brake delay device 60;

FIG. 3 is a cross-sectional view showing a multi-stage aperture 85 in an enlarged manner.

FIG. 4 is a cross-sectional view showing the structure of a conventional piston motor 1.

FIG. 5 is an enlarged sectional view showing the vicinity of the brake delay device 10;

[Explanation of symbols]

 Reference Signs List 30 piston motor 31 casing 32 rotating shaft 33 casing main body 34 end wall 50 brake piston 54 spring member 60 brake delay device 65 pressure port 71 plunger 74 first oil passage 75 second oil passage 80 ball check valve 85 multistage throttle

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[Procedure amendment]

[Submission date] February 2, 2000 (200.2.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015]

According to a first aspect of the present invention, there is provided a rotary shaft, a casing for rotatably supporting the rotary shaft about its axis, and a cylinder block rotating with the rotary shaft in the casing. A brake piston provided in the casing so as to be displaceable along the axial direction of the rotating shaft; a spring member interposed between the brake piston and the casing to bias the brake piston toward one side in the axial direction; A hydraulic chamber is formed between the piston and the casing, and in a state where hydraulic oil having a predetermined pressure or more acts on the hydraulic chamber, the brake piston moves toward the other side in the axial direction against the spring force of the spring member. When the hydraulic oil acting on the hydraulic chamber is displaced below the predetermined pressure, the brake piston is moved by the spring return force of the spring member. In a piston motor that brakes a cylinder block by being displaced to one side in a linear direction, a plunger is detachably attached to the casing, and a first oil that communicates a pressure port to which hydraulic oil is supplied with the hydraulic chamber. A passage is formed, and the plunger has a first
A second fluid passage communicating with the oil passage for discharging hydraulic oil in the hydraulic chamber;
An oil passage is formed, and a connecting portion between the first oil passage and the second oil passage includes:
A check valve is provided to allow the flow of hydraulic oil from the pressure port to the hydraulic chamber and to prevent the flow of hydraulic oil from the hydraulic chamber to the pressure port, and the second hydraulic path includes a plurality of plates having orifices, And a multi-stage throttle constituted by a spacer interposed between the plates.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

According to the present invention, in a state where hydraulic oil having a predetermined pressure or more acts on the pressure chamber from the pressure port via the first oil passage, the brake piston is displaced to the other side in the axial direction, and the rotating shaft is rotated. It is rotatable. When stopping the rotation of the rotating shaft, the hydraulic oil supplied to the pressure port is shut off. Then, the pressure of the hydraulic oil acting on the pressure chamber becomes lower than the predetermined pressure, and the brake piston starts to be displaced to one side in the axial direction by the spring return force of the spring member. The hydraulic oil starts to drain through. The connection between the first oil passage and the second oil passage is provided with a check valve that allows the flow of hydraulic oil from the pressure section to the hydraulic chamber and prevents the flow of hydraulic oil from the pressure chamber to the pressure port. The hydraulic oil discharged from the hydraulic chamber is discharged via the second oil passage. By discharging the hydraulic oil in the hydraulic chamber in this way, the brake piston is displaced to one side in the axial direction by the spring force, and the rotation of the rotating shaft can be fixed by applying the brake force. In the above-described prior art, the structure is complicated because the flow path is switched by using the spool and the orifice spool to discharge the hydraulic oil in the hydraulic chamber. However, in the present invention, the check valve is connected to the first valve as described above. Since the flow path is switched by providing the connection portion between the oil passage and the second oil passage, the structure can be simplified. Thereby, the configuration of the piston motor can be reduced in size and the weight can be reduced. Also,
Since the multi-stage throttle is interposed in the second oil passage, the hydraulic oil in the hydraulic chamber is slowly discharged through the multi-stage throttle when discharged through the second oil passage. This allows the brake to be delayed while the inertial body stops. By interposing the check valve and the multi-stage throttle in the second oil passage in this way, it is possible to have an inline structure, so that the configuration can be greatly simplified as compared with the related art.
Although a configuration in which a choke is interposed in place of the multistage throttle may be considered, the flow resistance of the choke largely depends on the viscosity of the hydraulic oil. That is, the delay time of the brake greatly varies depending on the temperature of the hydraulic oil. On the other hand, by using a multi-stage orifice throttle as in the present invention, the brake delay time can be made substantially constant regardless of the temperature of the hydraulic oil.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Deleted

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

[0034]

As described above, according to the present invention, since the check valve is provided in the first oil passage, the first oil passage does not require a complicated structure as in the prior art, and is discharged from the hydraulic chamber with a simple structure. The operating oil can be switched to the second oil passage side. Further, since a multi-stage throttle is interposed in the second oil passage, an orifice spool having a complicated configuration as in the related art is not required, and the flow rate of the hydraulic oil discharged from the hydraulic chamber is restricted to reduce the brake piston. It can be displaced slowly. Further, the check valve and the multistage throttle are configured in the second oil passage, so that the inline structure can be made extremely simple as compared with the conventional configuration. By thus simplifying the structure, the weight of the piston motor can be reduced.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Deleted

Claims (2)

[Claims] 1. A rotating shaft, a casing for rotatably supporting the rotating shaft around its axis, a cylinder block rotating with the rotating shaft in the casing, and a displacement in the casing along an axial direction of the rotating shaft. A hydraulic chamber is formed between the brake piston and the casing, a spring member interposed between the brake piston and the casing, the spring member biasing the brake piston to one side in the axial direction, In a state where hydraulic oil having a predetermined pressure or higher acts on the hydraulic chamber, the brake piston is displaced to the other side in the axial direction against the spring force of the spring member, and the hydraulic oil acting on the hydraulic chamber is When the pressure falls below a predetermined pressure, the brake piston is displaced to one side in the axial direction by the spring return force of the spring member, and the cylinder piston blows. In the piston motor, the casing is provided with a pressure port through which hydraulic oil is supplied, a first oil path that communicates the pressure port with the hydraulic chamber, and a hydraulic oil that communicates with the first oil path and is in the hydraulic chamber. Second for discharging
An oil passage is formed, and at the connection between the first oil passage and the second oil passage, the flow of hydraulic oil from the pressure port to the hydraulic chamber is allowed, and the flow of hydraulic oil from the pressure chamber to the pressure port is blocked. A piston motor provided with a check valve. 2. The piston motor according to claim 1, wherein a multi-stage throttle is interposed in the second oil passage.