JP2001280306A - Hydraulic hammer driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient hydraulic hammer driving device allowing stable work for hammering. SOLUTION: The hydraulic hammer driving device comprises a variable displacement hydraulic pump for supplying a hydraulic oil to a hydraulic hammer, a temperature sensor for detecting the temperature of the hydraulic oil and a falling height detecting sensor for detecting the falling height of a ram. When the falling height detected by the falling height detecting sensor exceeds a preset falling height and the temperature detected by the temperature sensor exceeds an allowable temperature, the discharge amount of the variable displacement hydraulic pump is reduced (Steps 110, 130, 160). When the temperature detected by the temperature sensor is lower than the allowable temperature and the falling height detected by the falling height detecting sensor is smaller than the preset falling height, the discharge amount is increased (Step 150).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic hammer driving device which raises a ram by a hydraulic cylinder and then drops the ram to strike a pile or the like.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic hammer for hitting a pile or the like used in civil engineering work or the like, a tip of a cylinder rod 104 of a hydraulic cylinder 102 is connected to a ram 100 as shown in FIG. And the hydraulic cylinder 1
02 and the hydraulic pump 106 are connected via an electromagnetic switching valve 108.

Hydraulic oil discharged from a hydraulic pump 106 is supplied to an ascending working chamber 102a via an electromagnetic switching valve 108, and hydraulic oil in a falling working chamber 102b is supplied to a tank 112 via a pilot check valve 110. Missed, raising the ram 100. Further, at the time of drop, the electromagnetic switching valve 108 is switched to release the hydraulic oil in the ascending working chamber 102a to the tank 112, and the ram 100 is dropped.

[0004]

In such a conventional apparatus, since the hydraulic pump 106 is driven at a constant speed by the engine, the discharge amount from the hydraulic pump 106 is constant. Excess hydraulic oil is released to the tank 112 via the relief valve 114. However, when the hydraulic cylinder 102 is reciprocated, there is a momentary time during which the hydraulic oil does not flow between the top dead center and the bottom dead center, and the hydraulic oil at that time is released to the tank 112 via the relief valve 114. However, the work is turned into heat, and the temperature of the hydraulic oil rises. Frequent reciprocating movements increase the temperature of the hydraulic oil.

[0005] When the temperature of the hydraulic oil rises, the viscosity of the hydraulic oil decreases. Therefore, when the electromagnetic switching valve 108 is switched by a timer, the rising distance increases.
The hitting power of the ram increases. For this reason, there is a trouble that the time setting of the timer must be changed as the temperature rises. If the temperature of the hydraulic oil exceeds the upper limit, the operation must be interrupted to protect the hydraulic equipment.However, work may not be interrupted on the way due to construction work, and this may impose a burden on the hydraulic equipment. There was also a problem.

An object of the present invention is to provide an efficient hydraulic hammer driving device capable of performing a stable hitting operation.

[0007]

In order to achieve the above object, the present invention takes the following means to solve the problem. That is, in a hydraulic hammer driving device that raises the ram with a hydraulic cylinder and then drops and hits the ram, a variable displacement hydraulic pump that supplies hydraulic oil to the hydraulic hammer and detects the temperature of the hydraulic oil. A hydraulic hammer driving device, comprising: a temperature sensor; and a flow control means for reducing a discharge amount of the variable displacement hydraulic pump when a temperature detected by the temperature sensor exceeds an allowable temperature. .

Further, in a hydraulic hammer driving device for lowering and hitting the ram after raising the ram by a hydraulic cylinder, a variable displacement hydraulic pump for supplying hydraulic oil to the hydraulic hammer; And a flow control means for reducing the discharge amount of the variable displacement hydraulic pump when the drop height detected by the drop height detection sensor exceeds a set drop height. This is a hydraulic hammer driving device characterized in that it is provided.

In addition, a drop height detecting sensor for detecting a drop height of the ram is provided, and the flow rate control means includes:
The discharge amount of the variable displacement hydraulic pump may be decreased even when the drop height detected by the drop height detection sensor exceeds the drop height. Alternatively, the flow control means may further increase the discharge amount of the variable displacement hydraulic pump when the temperature detected by the temperature sensor is lower than an allowable temperature. Also,
The flow control means may further increase the discharge amount of the variable displacement hydraulic pump when the drop height detected by the drop height detection sensor is smaller than a set drop height.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, reference numeral 1 denotes a ram, and the ram 1 is connected to a tip of a cylinder rod 4 of a hydraulic cylinder 2. Working chamber 2a for raising hydraulic cylinder 2
The working chamber 2b for dropping is connected to an electromagnetic switching valve 4, and the electromagnetic switching valve 4 is connected via a supply flow path 6 to a variable displacement hydraulic pump 8 capable of changing the discharge amount.

The electromagnetic switching valve 4 shuts off the supply flow path 6, and a drop position 4 a that connects the ascending action chamber 2 a and the drop action chamber 2 b to the tank 10 via the return flow path 7. And a rising position 4b for communicating the falling working chamber 2b and the tank 10 with each other, and the rising position 4b when the excitation signal is input.
b. The supply flow path 6 and the dropping action chamber 2
b is connected to the accumulators 12 and 14, respectively.

The supply passage 6 is communicated with the tank 10 via a relief valve 16 so that the operating oil pressure in the supply passage 6 does not rise above the set pressure of the relief valve 16. The hydraulic oil in the tank 10 is supplied to the oil cooler 1.
Also provided is a hydraulic pump 20 for supplying to the pump 8, and the variable displacement hydraulic pump 8 and the hydraulic pump 20 are connected so as to be rotationally driven at a constant speed by an engine 22.

Further, a temperature sensor 24 for detecting the temperature of the hydraulic oil in the return passage 7 is provided, and a drop height detection sensor 26 for detecting the height when the ram 1 is raised. The temperature sensor 24 may detect the temperature of the hydraulic oil in the pump suction passage 9.

The electromagnetic switching valve 4, the variable displacement hydraulic pump 8, the temperature sensor 24 and the drop height detecting sensor 26 described above.
Is connected to an electronic control circuit 50. The electronic control circuit 50 is configured as a logical operation circuit centered on a well-known CPU 52, ROM 54, RAM 56, and the like. Connected to each other.

The CPU 52 inputs input signals from the temperature sensor 24 and the drop height detection sensor 26 via an input / output circuit 58, and based on these signals, data in the ROM 54 and the RAM 56, and control programs stored in advance. C
The PU 52 outputs a drive signal to the electromagnetic switching valve 4 and the variable displacement hydraulic pump 8 via the input / output circuit 58.

Next, the flow rate control process performed in the electronic control circuit 50 will be described with reference to the flowchart of FIG. First, the variable displacement hydraulic pump 8 and the hydraulic pump 20 are driven by the engine 22. Further, the electronic control circuit 50 executes a timer process to switch the electromagnetic switching valve 4 according to a preset time. When the electromagnetic switching valve 4 is switched to the ascending position 4b, the hydraulic oil discharged from the variable displacement hydraulic pump 8 is supplied to the ascending working chamber 2a via the electromagnetic switching valve 4, and the working oil in the falling working chamber 2b is provided. The hydraulic oil is supplied to the accumulator 14 via the electromagnetic switching valve 4.
And returned to the tank 10.

Accordingly, the hydraulic cylinder 2 is driven, and the ram 1 is raised. When a preset time has elapsed, the electromagnetic switching valve 4 is switched to the falling position 4a, the dropping action chamber 2b and the rising action chamber 2a are communicated, and the dropping action chamber 2b is actuated from the accumulator 14. Oil is supplied and the ram 1 falls. At that time, part of the unnecessary hydraulic oil is released to the tank 10.

When the ram 1 falls, it hits a stake (not shown) or the like.
Is switched to the ascending position 4b. Then, when the hydraulic cylinder 2 is driven again and the ram 1 rises, the falling height of the ram 1 at that time is detected by the falling height detection sensor 26 and input to the electronic control circuit 50.

The flow rate control process is executed by interruption. First, the drop height detected by the drop height detection sensor 26 is measured (step 100). Next, it is determined whether or not the measured drop height is smaller than a preset drop height (step 110). When small, the temperature sensor 2
Then, the temperature of the hydraulic oil is measured based on the signal from Step 4 (Step 120). The set drop height is set in advance by an operator according to the work content.

It is determined whether the measured temperature of the hydraulic oil is lower than a preset allowable temperature (step 13).
0). The allowable temperature is an upper limit temperature set for protection of the hydraulic equipment and the like. If the temperature is lower than the permissible temperature, it is determined whether or not the striking operation by the ram 1 is to be stopped based on whether or not a stop switch (not shown) operated by an operator is on (step 140).

If it is determined that the operation is not stopped, the discharge amount of the variable displacement hydraulic pump 8 is increased (step 150).
Then, the control process is repeatedly executed to measure the drop height of the ram 1 (step 100). When the drop height is small, the discharge amount is further increased, and the drop height of the ram 1 is increased by increasing the discharge amount. Exceeds the set drop height, the discharge amount of the variable displacement hydraulic pump 8 is reduced (step 1).
60).

As described above, when the ram 1 repeatedly hits a pile or the like, the temperature of the hydraulic oil gradually increases, and when the viscosity of the hydraulic oil decreases, the falling height of the ram 1 by the hydraulic cylinder 2 increases. If the drop height measured by the processing in step 100 exceeds the set drop height, step 160
By executing the process (1), the discharge amount of the variable displacement hydraulic pump 8 is reduced, and the drop height is reduced.

Also, when it is determined that the temperature of the hydraulic oil has risen and the allowable temperature has been exceeded by executing the processing of step 130, the discharge amount of the variable displacement hydraulic pump 8 is reduced. As a result, the load is reduced, and the temperature rise of the hydraulic oil can be suppressed, and the hitting operation can be continued without stopping. Therefore, a stable striking operation can be performed, and the striking operation can be efficiently continued. On the other hand, if it is determined to be stopped by executing the processing of step 140, the switching of the electromagnetic switching valve 4 is stopped, and the present control processing is temporarily ended (step 170).

The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

[0025]

As described above in detail, the drive control device for a hydraulic hammer according to the present invention reduces the discharge amount of the variable displacement hydraulic pump when the temperature of the hydraulic oil exceeds the allowable temperature, thereby increasing the temperature. Therefore, there is an effect that a stable striking operation can be performed efficiently. Also, when the drop height exceeds the set drop height, the discharge amount of the variable displacement hydraulic pump is reduced to prevent a change in the impact force due to a rise in the temperature of the hydraulic oil, etc. This has the effect of being able to perform well.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a drive control device of a hydraulic hammer as one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a flow rate control process performed in the electronic control circuit according to the embodiment.

FIG. 3 is a schematic configuration diagram of a conventional drive control device for a hydraulic hammer.

[Explanation of symbols]

1,100 ram 2,102 hydraulic cylinder 4,104 cylinder rod 4,108 electromagnetic switching valve 6 supply flow path 7 return flow path 8 variable displacement hydraulic pump 9 pump suction flow path 12,14 ... Accumulators 16,114 ... Relief valve 18 ... Oil cooler 20 ... Hydraulic pump 22 ... Engine 24 ... Temperature sensor 26 ... Fall height detection sensor 50 ... Electronic control circuit

Claims (5)

[Claims] 1. A hydraulic hammer driving device that raises a ram by a hydraulic cylinder, drops the ram, and strikes the ram, comprising: a variable displacement hydraulic pump that supplies hydraulic oil to the hydraulic hammer; and a temperature of the hydraulic oil. And a flow rate control means for reducing a discharge amount of the variable displacement hydraulic pump when a temperature detected by the temperature sensor exceeds an allowable temperature. . 2. A hydraulic hammer drive device which raises a ram by a hydraulic cylinder, drops the ram, and strikes the ram, comprising: a variable displacement hydraulic pump for supplying hydraulic oil to the hydraulic hammer; And a flow control means for reducing the discharge amount of the variable displacement hydraulic pump when the drop height detected by the drop height detection sensor exceeds a set drop height. A hydraulic hammer driving device, comprising: 3. The apparatus according to claim 1, further comprising a drop height detection sensor for detecting a drop height of the ram, wherein the flow rate control means determines that the drop height detected by the drop height detection sensor is equal to a set drop height. The hydraulic hammer driving device according to claim 1, wherein the discharge amount of the variable displacement hydraulic pump is reduced even when the amount exceeds the predetermined value. 4. The flow control device according to claim 1, wherein the flow rate control means further increases a discharge amount of the variable displacement hydraulic pump when a temperature detected by the temperature sensor is lower than an allowable temperature. 3. The hydraulic hammer driving device according to 3. 5. The apparatus according to claim 5, wherein the flow rate control means further increases the discharge amount of the variable displacement hydraulic pump when the drop height detected by the drop height detection sensor is smaller than a set drop height. Claims 2 to 4
The hydraulic hammer drive as described.