JP2000145707A - Hydraulic motor device having relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an operating pressure of a relief valve to two steps so as to smooth a boost pattern at brake starting time at high pressure setting time, and to maintain a low pressure at a low pressure setting time. SOLUTION: In this hydraulic motor device having relief valves 50A, B constituted to be arranged in both pipe lines of a hydraulic motor 52 to be relieved by opening a puppet by a pressure rise of a supply port 64, in deceleration stopping rotation of the hydraulic motor 52, also to introduce pressure oil of the supply port to a spring seat piton chamber through a pressure compensation flow regulating means 68 so as to adjust a relief pressure by moving a spring seat piston 74, the hydraulic motor device is constituted such that a passage opening adjusting means 70 with an opening adjusted by an external signal is provided in an oil path connected to the spring seat piston chamber, a moving time from the initial position of the spring seat piston to movement of a prescribed stroke can be adjusted by the external signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic motor device having a relief valve applicable to an inertial body drive circuit for controlling a turning drive device of a hydraulic shovel or the like.

[0002]

2. Description of the Related Art In general, an inertial body drive circuit is configured to control the drive direction of a hydraulic motor by controlling the rotation direction and stop of hydraulic oil of a hydraulic pump by a switching valve. Therefore, when the hydraulic motor is rotating in one direction, the switching valve is returned to the neutral position to stop driving the inertial body.
The return path of the hydraulic motor is closed by the switching valve,
The inertial body has inertial rotational force, and the hydraulic pressure on the return side rises sharply, increasing energy, causing a shock,
The gears of the hydraulic motor may be damaged.

For this reason, it has been conventionally proposed to install a relief valve in a hydraulic circuit to prevent a sudden increase in hydraulic pressure (Japanese Utility Model Publication No. 63-21814).

That is, the relief valve according to this proposal is:
When the pressure in the supply passage 2 is low, the relief valve 1 is in the non-operating state and the outer poppet 4
Is pressed to the left by a spring 7 via a receiver 5 and a spring receiver 6 to come into contact with the seat 8 and a spring seat piston 9
Are in contact with the plug 10 and shut off the supply passage 2 and the return passage 3 as shown in FIG.

Therefore, when the pressure in the supply passage 2 rises,
This pressure oil acts on the outer poppet 4, moves the outer poppet 4 rightward against the elasticity of the spring 7, and
And the return passage 3 to start the relief action. On the other hand, the pressure oil is supplied to the eccentric hole 11 of the outer poppet 4 and the hole 1.
2 flows into the axial passage 13 through the
4. Spring seat piston chamber 17 through annular groove 15 and passage 16
Will be introduced. The pressure oil in the spring seat piston chamber 17 moves the spring seat piston 9 to the left from the illustrated position against the elasticity of the spring 7 in response to the increase in the pressure of the supply passage 2.

As a result, the spring 7 is further compressed, so that the relief pressure increases. By the movement of the spring seat piston 9, the lateral hole 14 of the rod 18 gradually decreases the opening area, thereby reducing the amount of pressure oil to the spring seat piston chamber 17. Further, the spring seat piston 9 moves,
Since the opening of the lateral hole 14 is closed and the flow of the pressure oil into the spring seat piston chamber 17 is substantially eliminated, the spring seat piston 9
The left-end position of is maintained.

As described above, the increase in the set pressure becomes gentler as it approaches the upper limit value, so that the shock caused by the sudden rise pressure when the relief valve 1 is started can be reduced. When the pressure in the supply passage 2 becomes equal to or less than the set value, the pressure in the spring seat piston chamber 17 acting on the right end face of the spring seat piston 9 decreases, and the spring seat piston 9 moves to the position shown in FIG. Return to and prepare for the next operation.

Therefore, in the relief valve configured as described above, when the pressure in the supply passage 2 rises, the outer poppet 4 first moves rightward against the elasticity of the spring 7 and at the same time, the spring seat piston 9 Pressure oil flows into the right spring seat piston chamber 17, and the spring seat piston 9 moves to the left to compress the spring 7 and increase its elastic force (relief pressure). With the leftward movement of the spring seat piston 9, the opening area of the lateral hole 14 into which the pressure oil flows into the spring seat piston chamber 17 becomes small. The relief pressure balanced with the elastic force of the spring 7 compressed between the spring seat piston 9 and the spring receiver 6 held at the pressure becomes the set pressure, and has an effect of reducing the pressure peak at the time of starting the relief valve 1. Can be done.

However, in the relief valve having the above-described structure, the pressure oil action area of the spring seat piston 9 is determined by the outer diameter of the spring seat piston 9 fitted in the hole 20 of the cap forming the spring chamber 19 in which the spring 7 is loaded. And a relatively large area in a ring shape sandwiched between the inner diameter of the inner hole 21 of the spring seat piston 9 into which the rod 18 is inserted. The spring seat piston 9 starts to move to the left even at a pressure as low as the back pressure generated in the return passage during the rotation of the spring, and when the pressure in the supply passage 2 rises, the pressure oil is supplied to the spring seat piston chamber 17. The horizontal hole 14 necessary for inflow of air is already closed because the spring seat piston 9 has already moved to the left. After the horizontal hole 14 is closed, a large peak is eliminated to reduce shock. It has not been possible.

[0010] From such a viewpoint, the present applicant firstly
When the pressure in the supply passage increases, the spring is compressed to increase the relief pressure so that the pressure oil working area of the spring seat piston can be reduced. A patent was developed to obtain a patent for a hydraulic motor relief valve that eliminates pressure peaks at the start of the relief valve and reduces shock when the pressure in the supply passage rises without moving and the pressure rises. No. 2571928).

That is, the relief valve of the hydraulic motor according to this patent, as shown in FIGS. 8 and 9, drives an inertial load with pressure oil supplied and discharged from a hydraulic pump 22 via a switching valve 23. When the rotation of the hydraulic motor is stopped, the pressure in the supply port causes the poppet 25 to move and open against the spring 26 that presses one end against its back when the rotation of the hydraulic motor is stopped. By releasing the pressure oil to the outlet and introducing the pressure oil from the supply port to the spring seat piston chamber 27 via the throttle 28, the spring seat piston 29 pressed against the other end of the spring 26 is moved. In the relief valves 30A and 30B of the hydraulic motor 24 for moving and adjusting the relief pressure by compressing the spring 26, an inner hole 32 having a smaller diameter than the inner hole 31 loaded with the spring 26 is provided. By movably fitting a spring seat piston 29 having a reduced pressure oil working area, the spring seat piston 29 is held at an initial position at a pressure of about the back pressure generated in the return passage when the hydraulic motor rotates. It is configured not to be moved.

However, the relief valves 30A, 30B
8 and 9, when the switching valve 23 is in the neutral state shown in the drawing, there is no pressure in the supply passages 32A and 32B, that is, the supply port 33 in FIG.
0A and 30B are inactive, and the tip of the poppet 25 is pressed to the left by the elastic force of the spring 26, and
4, the supply port 33 and the outlet 35 are shut off.

When the switching valve 23 is switched from the neutral position to the upper position, the pressure oil of the hydraulic pump 22 is supplied to the switching valve 23.
The hydraulic fluid flows into the hydraulic motor 24 from the pipe 36 through the pipe 36 and rotates in one direction, and the hydraulic oil discharged from the hydraulic motor 24 flows from the pipe 37 through the switching valve 23 to the tank 38.
It is returned. Next, when the switching valve 23 is switched to the neutral position in order to stop the hydraulic motor 24 from the rotating state, the circuits of the hydraulic pump 22 and the tank 38 are cut off in the pipes 36 and 37, respectively. , The hydraulic motor 24 does not stop immediately and the pressure in the conduit 37 rises. Therefore, the pressure at the supply port 33 of the relief valve 30B rises through the supply passage 32B, and the poppet 2
5, the supply port 33 has an effective sectional area formed by the difference (D1> D2) between the valve seat diameter D1 of the seat 34 and the diameter D2 of the rod 40.
The force of the pressure oil acts to move to the right against the elastic force of the spring 26, and the supply port 33 and the outlet 35 are communicated through the opened valve seat of the seat 34 and the lateral hole 41. This starts the relief action.

At the same time, the pressure oil in the supply port 33 is
5 and the passage 4 from the passage 42 of the rod 40 through the throttle 28
3 and is introduced into the spring seat piston chamber 27, and the pressure oil in the spring seat piston chamber 27 increases in pressure in response to the increase in the pressure in the supply port 33, and causes the spring seat piston 29 to move into the spring 26.
To the left against the elasticity of As a result, the spring 2
6 is further compressed and the relief pressure increases. The leftward movement of the spring seat piston 29 is stopped by moving the stroke L until the left side surface 45 of the flange portion 44 of the spring seat piston 29 comes into contact with the wall surface 47 of the valve body 46 with the increase in the pressure of the spring seat piston chamber 27. The relief pressure at the time of the stop is the set pressure.

[0015] The pressure oil thus relieved is:
The outlet 35 is supplied to the hydraulic motor 24 through the outlet passage 48B and the check valve 49A in FIG.

The flow of the pressure oil into the spring seat piston chamber 27 is gentle because the throttle 28 is provided in the middle of the passage 42 and the passage 43, and therefore the relief pressure rises slowly, and the pressure rises sharply. Has alleviated the shock. Further, it is also possible to increase the set pressure by increasing the stroke L in which the spring seat piston 29 moves.

[0017]

In the above-described relief valve of a hydraulic motor according to the prior art, as shown in FIG. 8, when the pressure of the supply port 32A, that is, the supply port 33 in FIG. The fluid flows into the spring seat piston chamber 27 via a passage 42 provided inside the poppet 25. Further, the inflowing pressure oil acts on the spring seat piston 29. When the pressure oil exceeds a certain value, the spring oil is moved to the left in the drawing while compressing the spring 26 against the load of the spring 26.

In this movement process, since the pressure oil flows into the spring seat piston chamber 27 through the throttle 28, it takes some time for the spring seat piston 29 to move from the illustrated position to the position in contact with the chamber wall 47. When the poppet 25 of the relief valve performs an opening operation in this process, the poppet 2
The load of the spring 26 acting on the spring 5 is initially from the position shown in the drawing, and finally becomes the load at the position where the spring seat piston 29 abuts the chamber wall 47. A dynamic characteristic that gradually increases in accordance with the movement of the spring seat piston 29 is obtained.

In a hydraulic circuit for driving a large inertia body, for example, an upper swing body of a hydraulic excavator, a relief valve of the swing motor as described above is often used, and a good result is obtained for reducing shock during braking. .

However, in the case of a hydraulic shovel or the like, the turning inertia is significantly different between a case where the boom and the arm are closer to the center of rotation and a case where the boom and the arm are closer to the horizontal state and a load is loaded on the bucket. . For this reason, in the above-described conventional technology, the shock immediately after the relief valve is actuated is reduced, but the pressure rise pattern is the same regardless of the difference in inertia due to the arm, boom posture, the presence or absence of the bucket load, and the like. For example, if the relief pressure is set in accordance with the state of small inertia, the flow angle at the time of the turning brake is large under the operating condition with large inertia, and if the relief pressure is set in accordance with the state of the large inertia, the inertia is reduced. Under the conditions, there is a problem in that the advantage of the hydraulic brake for turning becomes excessive, and smoothness at the time of stopping is impaired.

Japanese Patent Application Laid-Open No. Hei 6-173299 discloses a method for varying the set pressure of a relief valve for turning a hydraulic excavator in accordance with its posture, load conditions, and the like. However, in this prior art, since the set pressure is adjusted by an external signal, the structure of the relief valve becomes very complicated, not only increases the manufacturing cost, but also increases the reliability. There are difficulties that require consideration. Although it is possible to adjust the set pressure of the relief valve itself, when the set pressure is set to a relatively high pressure, it is possible to adopt a boost pattern in which the characteristics at the time of start and stop are gradually increased. However, there is still a problem that a shock remains at the time of deceleration stop.

Accordingly, the present inventors have conducted intensive studies and as a result, have found that both hydraulic motors for driving an inertial load formed by an upper swing body of a hydraulic shovel by hydraulic oil supplied and discharged from a hydraulic pump via a switching valve. When the rotation of the hydraulic motor is decelerated and stopped, the pressure rises at the supply port so that the poppet moves and opens against the spring resilience of pressing one end against the back of the hydraulic motor. By relieving the oil to the outlet and introducing the pressure oil of the supply port to the spring seat piston chamber via the pressure compensation flow rate adjusting means, the spring seat piston pressed against the other end of the spring is moved. In a hydraulic motor device having a relief valve configured to adjust a relief pressure by compressing the spring, a passage opening whose opening is adjusted by an external signal in an oil passage connected to the spring seat piston chamber. Adjusting means by adjusting the movement time from the initial position of the spring seat piston to a predetermined stroke by the external signal so that the deceleration stop performance of the hydraulic shovel can be optimally set. It has been found that a hydraulic motor device with a possible relief valve can be obtained.

Accordingly, an object of the present invention is to set the operating pressure of the relief valve in two stages by a very simple means, to smooth the pressure increasing pattern at the start of braking when high pressure is set, and to ensure the pressure increase pattern at low pressure. Another object of the present invention is to provide a hydraulic motor device having a relief valve configured so that a low pressure can be maintained.

[0024]

In order to achieve the above object, a hydraulic motor device having a relief valve according to the present invention drives an inertial load by pressure oil supplied and discharged from a hydraulic pump via a switching valve. The branch is disposed in both pipelines of the hydraulic motor, and when the rotation of the hydraulic motor is decelerated and stopped, the pressure rises at the supply port so that the poppet moves against the spring elasticity of pressing one end against its back and opens. Then, the pressure oil is relieved to the outlet, and the pressure oil of the supply port is introduced into the spring seat piston chamber via the pressure compensation flow rate adjusting means, so that the spring seat piston pressed against the other end of the spring. In the hydraulic motor device having a relief valve configured to adjust the relief pressure by compressing the spring, the opening degree is adjusted by an external signal to an oil passage connected to the spring seat piston chamber. The passage opening adjustment means is provided which, the travel time from the initial position of the spring seat piston to move a predetermined stroke, characterized in that adjustably constructed by the external signal.

In this case, the passage opening adjusting means may be constituted by a throttle valve which is arranged in an oil passage between the pressure compensation flow rate adjusting means and the spring seat piston chamber and whose opening is adjusted by an external signal. it can.

The passage opening adjusting means is disposed in a branch oil passage branched from an oil passage between the pressure compensation flow rate adjusting means and the spring seat piston chamber and connected to the low pressure side. An oil space is connected and disposed in the means, and the oil space includes at least a liquid-tight and slidable piston and a spring that acts on the piston in a direction in which the oil space is reduced. The oil passage may be configured to be communicated / blocked by the external signal.

Further, a signal line for supplying the external signal to a relief valve provided at each port of the hydraulic motor is configured to communicate with the inside of the hydraulic motor device. It can be configured such that the pressure-up time of each relief valve is simultaneously adjusted by a signal connected to a single signal port.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a hydraulic motor device having a relief valve according to the present invention will be described in detail with reference to the accompanying drawings.

[0029]Example 1  FIG. 1 shows a hydraulic motor device having a relief valve according to the present invention.
1 shows an embodiment of the present invention. In FIG.
Nos. 50A and 50B are mounted on the hydraulic motor 52.
Each shows a leaf valve. These relief valves 50A,
50B is built in the cover 54 of the hydraulic motor 52
I have. Then, the hydraulic motor 52 is connected to the inertial load 56 (the hydraulic pressure
When the present invention is applied to a shovel,
(The upper revolving superstructure). Ma
The hydraulic motor 52 is supplied with hydraulic pressure through a switching valve 58.
Supply and discharge of pressure oil between the pump 60 and the tank 62 are performed.
You. In this embodiment, the switching valve 58 is shown in FIG.
Although an example of the configuration is shown, the hydraulic pump 60 is provided with a hydraulic excavator.
Switching valve for other actuators not shown
For example, the switching valve of the arm cylinder is generally connected
I have.

Since the relief valves 50A and 50B attached to the cover portion 54 of the hydraulic motor 52 have the same configuration, only one relief valve 50A will be described, and detailed description of the other relief valve 50B will be omitted. I do.

A port of the switching valve 58 is connected to each port of the hydraulic motor 52, and a supply port 64 of the relief valve 50A is connected to a port Mp1 on one side of the hydraulic motor 52 (Mp2 is a port on the other side). Shown), and
A spring seat piston chamber 7 is provided via a passage 66, a pressure compensation flow rate adjusting means 68, and a variable throttle valve 70 as a passage opening degree adjusting means.
2 are connected. And the spring seat piston chamber 7
One end of a spring 76 is in contact with a spring seat piston 74 forming the second spring 2, and a poppet (not shown) is formed at a supply port 64 at the other end of the spring 76 at the other end of the spring 76, similarly to the above-described related art. (Not shown) elastically to maintain the relief valve 50A in the closing direction.

In such a state, if the hydraulic motor 52 is driven and then decelerated and stopped by operating the switching valve 58, it is assumed that an operating pressure of the hydraulic brake is generated at one port Mp1 of the hydraulic motor 52. Then, the operating pressure of the relief valve 50A is, first, at the time of starting, since the spring seat piston 74 is at the position shown in the figure, the load of the spring 76 is the smallest, that is, the relief valve 50A is at a low pressure.
Works. At the same time, when the pressure oil at the supply port 64 flows into the spring seat piston chamber 72 through the above-described passage, regardless of the pressure at the supply port 64, the pressure compensating flow rate adjusting means 6
Attempt to flow at a flow rate defined by 8.

In this case, the pressure compensation flow rate adjusting means 68
In the state where the variable throttle valve 70 as a passage opening adjusting means disposed in the oil passage between the spring seat piston chamber 72 and the
The moving speed of the spring seat piston 74 is determined by the flow rate (per unit time) determined by the pressure compensation flow rate adjusting means 68.

Further, by supplying a signal pressure to the external signal line 78, the variable throttle valve 70 can be adjusted to the throttle position. Is further restricted, so that the moving speed of the spring seat piston 74 is further restricted. The signal pressure is transmitted to the external signal line 78 by transmitting a hydraulic signal from a signal generating hydraulic pump 84 by a signal switching operation from a signal switching means 80 and a signal generating means 82 to the switching means 80. Can be achieved.

In FIG. 1, reference numerals 86A and 86A
6B is a check valve, 88 is a check valve with spring, and 90 is a tank.

The operating characteristics of the relief valves 50A and 50B in the hydraulic motor device of the present embodiment having the above-described configuration have a boost pattern as shown in FIG. In this pressure increasing pattern, the pressure waveform A-1 is a characteristic when the opening of the passage opening adjusting means (variable throttle valve 70) is fully opened.
2. The pressure waveform A-3 and the time required for the pressure to rise to the set pressure PS become longer. In FIG. 3, the initial pressure P1 corresponds to the case where the spring seat piston 74 shown in FIG. 1 is at the position shown, and the final set pressure PS corresponds to the case where the spring seat piston 74 is at the position where the maximum stroke S has moved. Show. The time from the initial pressure P1 to the final set pressure PS is referred to as a gradual pressure increase time Δt.

When the hydraulic motor device having the relief valve according to the present invention configured as described above is applied to a hydraulic shovel, the passage opening degree is determined according to the posture of the upper revolving unit, the load condition of the bucket, and the like. The pressure-up time of the relief valve can be adjusted by an extremely simple means using an external signal for the adjusting means (variable throttle valve 70), so that optimum startup acceleration and deceleration stop characteristics can be obtained.

In the embodiment shown in FIG. 1, the variable throttle valve 70 whose opening is adjusted by an external signal is provided between the pressure compensation flow rate adjusting means 68 and the spring seat piston chamber 72. As an alternative, the variable throttle valve 70 may be connected to the passage 6 for communicating the supply port 64 and the pressure-compensating flow rate adjusting means 68.
6 can be provided, and in this case, the same operation and effect as described above can be obtained.

[0039]Example 2  FIG. 2 shows a hydraulic motor device having a relief valve according to the present invention.
7 shows another embodiment of the device. The oil of the present embodiment
The basic configuration of the pressure motor device is the same as that of the above embodiment.
1 is the same as the hydraulic motor device described in FIG.
Components are assigned the same reference numerals and detailed explanations are given.
Explanations are omitted, and different components will be described in detail.
You.

That is, in the embodiment shown in FIG.
A variable throttle valve 7 as a passage opening adjusting means is connected to a branch oil passage branched from an oil passage from each supply port 64 of the relief valves 50A and 50B to the spring seat piston chamber 72 and connected to the low pressure side.
0, an oil space 92 is connected and arranged via the variable throttle valve 70, and a control piston 94 and a spring 96 are provided in the oil space 92.
6 displaces the control piston 94 by pressing in the direction of reducing the oil space 92. The opening degree of the variable throttle valve 70 is adjusted by the signal pressure supplied to the external signal line 78. When the signal pressure is not supplied, the branch oil passage is shut off, and the signal pressure is supplied. In such a case, it is configured to communicate with the branch oil passage. The other configuration is the same as the configuration of the hydraulic motor device having the relief valve of the first embodiment.

With such a configuration, when no signal pressure is applied to the external signal line 78, the passage 98 and the oil space 92 are shut off. The pressure oil that has flowed into the chamber 72 side causes the spring seat piston 74 to
Will be moved against the elasticity of Therefore, the moving speed of the spring piston 74 in this case is determined by the inflow amount (per unit time) passing through the pressure compensation flow rate adjusting means 68.

Next, when the signal pressure is supplied to the external signal line 78 and the passage 98 communicates with the oil space 92, the pressure oil flowing into the spring seat piston chamber 72 from the pressure compensation flow rate adjusting means 68 is applied to the spring seat 72. Acts on the piston 74 and also acts on the right end in the illustration of the control piston 94,
This is moved to the left in the figure against the elasticity of the spring 96. Accordingly, the pressure oil flowing from the pressure compensation flow rate adjusting means 68 to the spring seat piston chamber 72 side is used to move both the control piston 94 and the spring seat piston 74, so that only the movement of the spring seat piston 74 is performed. Is reduced as compared to the case where there is no supply to the oil space 92, so that the moving speed of the spring seat piston 74 is slower than when the signal pressure is not supplied to the external signal line 78. . As a result, the pressure raising time of the relief valves 50A and 50B becomes longer.

Therefore, the operating characteristics of the relief valve in the hydraulic motor device according to the present embodiment have a step-up pattern as shown in FIG. In this boost pattern, the pressure waveform B-
Reference numeral 1 denotes a characteristic in a case where the signal pressure from the external signal line 78 does not act on the passage opening adjusting means (variable throttle valve 70), and includes a pressure waveform B-2, a pressure waveform B-3, and a pressure waveform B-4.
Is a case where a signal pressure is supplied to the external signal line 78, respectively, and the respective pressure rising patterns correspond to the diameter and the stroke of the control piston 94 and the spring 9 as described above.
Various patterns can be set according to the load 6 and the like. In FIG. 4, the initial pressure P1 is obtained when the spring seat piston 74 shown in FIG.
The final set pressure PS indicates a case where the spring seat piston 74 is at the position where the maximum stroke S has been moved. The time from the initial pressure P1 to the final set pressure PS is referred to as a gradual pressure increase time Δt.

The hydraulic motor device having the relief valve according to this embodiment having the above-described configuration can obtain the same operation and effects as those of the hydraulic motor device according to the first embodiment.

The hydraulic motor device having the relief valve according to the present invention shown in each of the above-described embodiments, when applied to a hydraulic shovel as shown in FIGS. As a condition for applying an external signal to the throttle valve 70), the angle θ of the boom of the hydraulic excavator with respect to the upper revolving unit is detected, and accordingly, for example, when the boom is closer to horizontal (see FIG. 6), the external signal is output. No, and if the boom is more perpendicular to the revolving superstructure (see FIG. 5), by applying an external signal, the pressure rise time of the relief valve is adjusted by extremely simple means,
Optimum start-up acceleration and deceleration stop characteristics of the hydraulic excavator can be obtained.

Further, the holding pressure of the boom cylinder is detected,
If the holding pressure is high, no external signal is given, and if the holding pressure is lower than a predetermined pressure, an external signal is given. By applying the switching signal pressure to the opening degree adjusting means (variable throttle valve 70), the boosting time of the relief valve can be adjusted by extremely simple means, and the optimum starting acceleration, deceleration and stop characteristics of the excavator can be obtained. .

Further, in practice, an external signal is provided to the relief valve assembly provided for each supply port by a common (one) signal supply port provided in the cover of the hydraulic motor. In addition, the signal piping is simplified, and the handling is easy.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and many design changes can be made without departing from the spirit of the present invention.

[0049]

As is apparent from the above-described embodiment, the hydraulic motor device having the relief valve according to the present invention is a hydraulic motor that drives an inertial load by pressure oil supplied and discharged from a hydraulic pump via a switching valve. Branching into both pipelines,
When the rotation of the hydraulic motor is decelerated and stopped, the pressure rises at the supply port so that the poppet moves and opens against the spring resilience of pressing one end against the back of the supply port, opening the poppet, and relieving the pressure oil to the outlet. By introducing the pressure oil of the mouth to the spring seat piston chamber through the pressure compensation flow rate adjusting means, the spring seat piston pressed against the other end of the spring is moved, and the spring is compressed to reduce the relief pressure. In a hydraulic motor device having a relief valve configured to adjust,
The oil passage connected to the spring seat piston chamber is provided with a passage opening adjustment means whose opening is adjusted by an external signal, and the movement time from the initial position of the spring seat piston to a predetermined stroke is determined. Due to the configuration that can be adjusted by an external signal, even if the inertia of the inertial body differs depending on the posture and working conditions of the machine like a hydraulic excavator, the hydraulic pressure when decelerating and stopping this inertial body by an external signal Since the pressure rise time of the relief valve that performs the braking action can be adjusted by a very simple method, it is possible to obtain optimal deceleration / stop and start-up acceleration characteristics regardless of each working condition and posture.

[Brief description of the drawings]

FIG. 1 is a hydraulic system diagram showing one embodiment of a hydraulic motor device having a relief valve according to the present invention.

FIG. 2 is a hydraulic system diagram showing another embodiment of a hydraulic motor device having a relief valve according to the present invention.

FIG. 3 is a waveform chart showing pressure operation characteristics of a relief valve in the hydraulic motor of the embodiment shown in FIG.

FIG. 4 is a waveform chart showing pressure operation characteristics of a relief valve in the hydraulic motor of the embodiment shown in FIG.

FIG. 5 is an explanatory diagram showing a state where the turning inertia is relatively small in the case of a hydraulic shovel as an inertial load.

FIG. 6 is an explanatory diagram showing a state in which the turning inertia is relatively large in the case of a hydraulic shovel as an inertial load.

FIG. 7 is a cross-sectional view of a main part showing one configuration example of a relief valve of a conventional hydraulic motor.

FIG. 8 is an explanatory diagram showing a schematic configuration of another configuration example of a conventional relief valve of a hydraulic motor and a system arrangement thereof.

FIG. 9 is an enlarged sectional view of a main part of the relief valve shown in FIG.

[Explanation of symbols]

 50A, 50B Relief valve 52 Hydraulic motor 54 Cover 56 Inertia load 58 Switching valve 60 Hydraulic pump 62 Tank 64 Supply port 66 Passage 68 Pressure compensation flow rate adjusting means 70 Variable throttle valve (passage opening degree adjusting means) 72 Spring seat piston chamber 74 Spring seat piston 76 Spring 78 External signal line 80 Signal switching means 82 Signal generating means 84 Signal generating hydraulic pump 86A, 86B Check valve 88 Spring check valve 90 Tank 92 Oil space 94 Control piston 96 Spring 98 Passage Mp1, Mp2 Hydraulic motor port

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Takanashi 4-5676 Hibarigaoka, Zama City, Kanagawa Prefecture Toshiba Machine Co., Ltd. Sagami Office (72) Inventor Koji Sato 4-5676 Hibarigaoka, Zama City, Kanagawa Prefecture Toshiba Machine Co., Ltd. Sagami Plant F term (reference) 2D003 AA01 AB02 AC06 BA01 BA07 BB03 CA02 DA03 DB02 3H059 BB05 BB07 CC06 CD05 CD12 CF14 DD01 EE01 FF03 FF14 3H089 AA65 BB06 CC08 DA03 DB04 DB33 DB47 DB49 EE08 EE22 EE02 FF02

Claims (4)

[Claims] 1. A hydraulic motor for driving an inertial load with pressure oil supplied / discharged from a hydraulic pump via a switching valve. The hydraulic motor is branched into two pipelines, and when the rotation of the hydraulic motor is decelerated and stopped. Due to the increase in the pressure of the supply port, the poppet moves and opens against the spring resilience of pressing one end against the back, and the pressure oil is relieved to the outlet while the pressure oil of the supply port is pressed to the spring seat piston chamber. Hydraulic pressure having a relief valve configured to adjust the relief pressure by compressing the spring by moving the spring seat piston pressed against the other end of the spring by introducing through the compensation flow rate adjusting means In the motor device, a passage opening adjusting means whose opening is adjusted by an external signal is provided in an oil passage connected to the spring seat piston chamber, and a predetermined stroke is moved from an initial position of the spring seat piston. Hydraulic motor unit with a relief valve, characterized in that the travel time, and adjustably configured by the external signal at. 2. A throttle valve according to claim 1, wherein said passage opening adjusting means is disposed in an oil passage between said pressure compensation flow rate adjusting means and a spring seat piston chamber, and has an opening adjusted by an external signal. Hydraulic motor device having a relief valve. 3. The passage opening adjustment means is disposed in a branch oil passage branched from an oil passage between the pressure compensation flow rate adjustment means and a spring seat piston chamber and connected to a low pressure side. The oil space is connected to the means, and the oil space includes at least a liquid-tight and slidable piston and a spring that acts on the piston in a direction to reduce the oil space. 2. The hydraulic motor device having a relief valve according to claim 1, wherein the passage is configured to be communicated / cut off by the external signal. 4. A signal line for supplying an external signal to a relief valve provided at each port of the hydraulic motor is configured to communicate with the inside of the hydraulic motor device. The hydraulic motor device having a relief valve according to any one of claims 1 to 3, wherein a pressure connection time of each relief valve is simultaneously adjusted by a signal connected to one signal port.