JPH07101044B2 - Signal transmission device in hydraulic circuit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device for transmitting a signal for controlling the operation of a control device such as an actuator and a control valve incorporated in a hydraulic circuit. .

(Prior Art) In a conventional hydraulic circuit, the operation of the actuator is controlled by, for example, a switching valve provided in a control circuit that operates and stops the actuator.

(Problems to be Solved by the Invention) In the case of the conventional actuation control means such as an actuator, there is a problem that a dedicated control circuit for actuating and controlling the actuator is required and the hydraulic circuit becomes complicated.

It is an object of the present invention to simplify a control circuit that controls the operation of a control device such as an actuator.

(Means for Solving the Problem) According to the present invention, an opening / closing mechanism for opening and closing the return oil passage is installed in the middle of the return oil passage connected to a return tank at a remote position, and communicates with the return oil passage. At the tip of the hydraulic oil passage, a back member having a transmission member that is actuated and controlled by a change in back pressure in the hydraulic oil passage when the return oil passage is opened / closed by the opening / closing passage mechanism to operate the control mechanism. It has a configuration in which a pressure detection mechanism is installed.

(Operation) In the signal transmission device in the hydraulic circuit having the above-described configuration, when the return oil passage is closed by the opening / closing mechanism installed in the middle of the return oil passage, the transmission member of the back pressure detection mechanism moves in the working oil passage. The control mechanism is activated by the transmission member of the back pressure detecting mechanism.

(Example) Next, the present invention is mounted on the tip of a boom of a construction vehicle for crushing concrete or the like, and the number of hits of a hydraulic breaker B used by connecting to a hydraulic power source mounted on this vehicle. A first embodiment of the converter will be described with reference to FIGS. 1 to 6.

A shaft hole 1a is vertically provided at the center of the cylinder 1 of the hydraulic breaker B, and an impact tool 2 and a substantially cylindrical piston 3 for impacting the impact tool 2 are axially provided in the shaft hole 1a. A gas chamber 1b is formed which is slidably inserted and has the upper end of the cylinder 1 filled with nitrogen gas and into which the upper end of the piston 3 is projected.

In the vicinity of the central portion of the piston 3, the outer diameters of the upper portion 3a and the lower portion 3b of the piston 3 are enlarged, and the upper large diameter portion 3c and the lower large diameter portion 3d having the same outer diameter are vertically separated from each other. The large diameter portions 3c and 3d are closely fitted in a slide hole 4 formed in a step shape with respect to the upper portion of the shaft hole 1a of the cylinder 1. The outer diameter of the upper part 3a of the piston 3 is smaller than the outer diameter of the lower part 3b or is equal to the outer diameter of the lower part 3b, and the upper end of the upper large diameter part 3c receives the hydraulic pressure for pushing down the piston 3. While the upper pressure receiving surface 5 is formed, the lower large diameter portion 3d receives the hydraulic pressure for pushing up the piston 3, and the lower pressure receiving surface 5 has an area smaller than the area of the upper pressure receiving surface 5 or an equal area. The pressure receiving surface 6 is formed.

At the upper and lower ends of the peripheral surface of the slide hole 4 of the cylinder 1, the variable pressure chamber 7 into which the high pressure oil that pressurizes the upper pressure receiving surface 5 and the high pressure oil that pressurizes the lower pressure receiving surface 6 are constantly fed. High pressure chamber 8
And are respectively recessed annularly, and slide holes 4
A low-pressure chamber 9 and a main pilot chamber 10 which are passed and blocked by the movement of the lower large-diameter portion 3d are annularly provided in the vicinity of the central portion of the peripheral surface of the ring-shaped concave portion. Is a No. 1 installed between the main pilot chamber 10 and the high pressure chamber 8.
The first, second, and third sub-pilot chambers 11A, 11B, and 11C are respectively provided in annular recesses and arranged in order from the top, and the outer periphery of the lower portion 3b of the piston 3 between the main pilot chamber 10 and the high-pressure chamber 8 is arranged. A high-pressure oil passage 13 that is opened and closed and expanded and contracted by a moving operation of the lower pressure receiving surface 6 of the piston 3 is formed in a gap between the surface and the peripheral surface of the slide hole 4.

Further, the cylinder 1 has a variable pressure passage 14 communicating with the variable pressure chamber 7.
A high pressure passage 15 which communicates with the high pressure chamber 8 and an accumulator 20 attached to the side surface of the cylinder 1, a low pressure passage 16 which communicates with the low pressure chamber 9, and a main pilot chamber 10. And a pilot flow path 17 are formed to face the direction control valve 21 attached to one side surface of the cylinder 1, while the first switching flow path 18A communicated with the main pilot chamber 10 is formed.
And the second switching flow path 1 communicating with the first sub pilot chamber 11A
8B, a third switching passage 18C that communicates with the second auxiliary pilot chamber 11B, and a fourth switching passage 18D that communicates with the third auxiliary pilot chamber 11C. Are formed so as to face each other. A communication passage 12 is formed near the upper portion of the cylinder 1 so as to bypass the shaft hole 1a.

In the direction control valve 21 provided to change the moving direction of the piston 3, the plunger hole 22 formed in the valve body 22
A plunger 23 is slidably inserted into the inside of a and the return passage 2 is provided on the peripheral surface of the plunger hole 22a.
5, a low-pressure chamber 27 communicating with the low-pressure channel 26, a variable pressure chamber 29 communicating with the pilot channel 17 of the cylinder 1 via a variable pressure channel 28, and a low-pressure chamber communicating with the return channel 25. 30, and a variable pressure chamber 32 communicated with the variable pressure flow path 14 via the variable pressure flow path 31,
A high pressure chamber 36, which is in communication with the hydraulic pump 33 via the high pressure flow path 34 and is also in communication with the high pressure flow path 15 via the high pressure flow path 35, and is in communication with the low pressure flow path 16 via the low pressure flow path 37, and returns. A low pressure chamber 39, which communicates with the flow path 25 via a low pressure flow path 38, is formed in order from the top. In addition, the cylinder 1 is provided above the valve body 22.
A communication passage 19 communicating with the communication passage 12 and the return flow passage 25 is formed.

On the other hand, the plunger 23 has an upper middle diameter portion 23b and an upper large diameter portion 23c.
A small-diameter portion 23d, a lower large-diameter portion 23e, and a lower medium-diameter portion 23f whose outer diameter is slightly larger than that of the upper medium-diameter portion 23b are formed in this order from the top, and the upper end surface of the upper large-diameter portion 23c is formed. Is formed with an upper pressure receiving surface 23g for receiving the hydraulic pressure of the high pressure oil in the variable pressure chamber 29 that moves the plunger 23 downward, and the plunger 23 is retracted upward at the lower end surface of the lower large diameter portion 23e. The lower pressure receiving surface 23h for receiving the hydraulic pressure of the high pressure oil in the high pressure chamber 36 is formed, and the upper pressure receiving surface 2
The area of 3g is larger than the area of the lower pressure receiving surface 23h.

In the pilot valve 40, the first switching passage 18A has a second switching passage 18B,
Operation timing of the directional control valve 21 by switching between a state of selectively communicating with the third switching passage 18C or the fourth switching passage 18D and a state of not communicating with any of the passages 18B, 18C, 18D. It is attached to the cylinder 1 to control the. In the housing 41 of the pilot valve 40, a first communication channel 42A that communicates with the second switching channel 18B of the cylinder 1, a second communication channel 42B that communicates with the third switching channel 18C, and a fourth switching channel. The third communication channel 42C communicated with the channel 18D is formed at a position separated by 90 ° from each other. A stepped cylindrical rotatable valve element 44 is provided in a center hole 41a penetrating the center of the housing 41.
Is rotatably fitted in the rotatable valve body 44, and the rotatable valve body 44 is bored along the axial direction thereof to communicate with the first switching passage 18A.
5a and a radial hole 45b drilled along its radial direction
A rotatable flow channel 45 is formed by connecting and in an L shape.

The four interlocking pieces 43, which are slidably supported in the radial direction of the rotatable valve body 44 with respect to the outer peripheral portion of the rotatable valve body 44 and are arranged at rotationally symmetrical positions of 90 °, are outwardly extended by springs 46, respectively. It is urged to project into a guide hole 41b which is recessed along the outer peripheral surface of the rotatable valve body 44 with respect to the housing 41, and is elastically contacted with the peripheral surface of the guide hole 41b. For each interlocking piece 43, the tip of one interlocking piece 43 is elastically engaged with a lock hole 48 which is slightly recessed in a part of the peripheral surface of the guide hole 41b, and is forced around the axial center of the rotatable valve body 44. It is locked so that it can be pivoted.

It is installed facing the pilot valve 40, and the interlocking piece 43
The back pressure detecting mechanism 49 for selectively rotating the rotatable valve body 44 by 90 ° is a slide chamber 50 formed in a cylindrical case body fixed to the housing 41, and a slide chamber 50. 50
A sliding piece 49a slidably fitted therein, a transmission member 49b having a base end portion coupled to the sliding piece 49a and a distal end portion extending toward the distal end of the interlocking piece 43, and a sliding piece. 49a and transmission member
A spring 51 for urging 49b to the side opposite to the interlocking side is provided, and each interlocking piece 43 turns 90 ° and the rotatable valve body 40 turns 90 ° for each forward / backward movement of the transmission member 49b.

The radial hole 45b of the rotatable valve element 44 is the center hole 4 of the housing 41.
When rotated in the direction A so as to be blocked by the peripheral surface of 1a, the rotary flow passage 45 is blocked and the first switching flow passage 18A is closed,
When the rotatable valve body 44 is rotated in the B direction so that the radial hole 45b is directed to the first communication passage 42A side, the rotatable flow passage is formed.
45 communicates with the first communication channel 42A and the first and second switching channels 1
8A and 18b are communicated with each other so that the main pilot chamber 10 and the first sub-pilot chamber 11A are communicated with each other, and the rotatable valve body 44 is rotated in the C direction so that the radial hole 45b is directed to the second communication passage 42B side. When moved, the rotatable flow path 45 is connected to the second communication flow path 42B and the first switching flow path 18A and the third switching flow path 18C are connected to form the main pilot chamber 10 and the second auxiliary pilot chamber 11B. Communicated,
Further, the rotatable valve body 44 is provided with the radial hole 45b in the third communication passage 42C.
When turned in the D direction so as to be directed to the side, the rotatable flow passage 45 is communicated with the third continuous flow passage 42C and the first switching flow passage 18A.
Is communicated with the fourth switching passage 18D so that the main pilot chamber 10 and the third sub pilot chamber 11C are communicated with each other.

A communication conduit 52 communicating with the outer end of the slide chamber 50 of the back pressure detection mechanism 49 is connected to the communication conduit 12 of the cylinder 1, and both communication conduits 12 and 19 and the communication conduit 52 are connected in series. The hydraulic fluid passage 53 communicated with the return flow passage 25 of the directional control valve 21 and the slide chamber 50 of the back pressure detection mechanism 49, and the pressure oil for driving and controlling the back pressure detection mechanism 49 is passed through the hydraulic fluid passage 53 to the slide chamber. Delivered to 50.

The return flow path 25 of the directional control valve 21 and the remote return tank 24
An open / close circuit mechanism 56 is connected in the middle of the return oil passage 55 that is piped for communicating with the return oil passage 55. A switching valve that is turned on / off by a switch operation, a solenoid valve that is turned on / off by a pulse signal, or the like is applied as the opening / closing mechanism 56.
Is a 2-port 2-position switching valve.
The switch 57 connected to 56 is turned on and off.

When the opening / closing mechanism 56 is turned off and the return oil passage 55 is opened, the waste oil in the directional control valve 21 is sent out into the return tank 24 through the return passage 25 and the return oil passage 55, and the piston 3 is normally moved forward and backward. The operation is repeated. On the other hand, when the switching mechanism 56 is turned on and the return oil passage 55 is closed, the back pressure in the return oil passage 55 and the hydraulic pressure in the hydraulic oil passage 53 increase, and this back pressure change becomes an output signal and the back pressure is changed. The rod 49b of the detection mechanism 49 moves,
It is possible to control the rotation of the rotatable valve element 44 of the pilot valve 40 by advancing and retracting the rod 49b every time the switching mechanism 56 is turned on and off.

Subsequently, the operation and effect of the above-described embodiment will be described.

Now, as shown in FIG. 1, when the piston 3 is retracted to the upper end and the plunger 23 of the switching valve 21 is advanced to the lower end, the high pressure oil flows into the high pressure passage 34, the high pressure chamber 36 and the high pressure passage 34. Since the high pressure chamber 36 and the variable pressure chamber 32 are communicated with each other by being sent into the high pressure chamber 8 of the cylinder 1 through the high pressure passage 35, the high pressure oil is transferred to the high pressure chamber.
36, the variable pressure chamber 32, the variable pressure flow passage 31, and the variable pressure flow passage 14 are fed into the variable pressure chamber 7 of the cylinder 1, and the area difference between the upper pressure receiving surface 5 and the lower pressure receiving surface 6 and the gas pressure in the gas chamber 1b. The piston 3 moves downward by the and to strike the impact tool 2.

When the piston 3 moves to the lower end, the main pilot chamber 10 of the cylinder 1 is communicated with the low pressure chamber 9, so that the pressure inside the main pilot chamber 10 and the pressure changing chamber 29 of the directional control valve 21 is reduced, and the bottom of the plunger 23 is lowered. The pressure receiving surface 23h is pushed up by the high pressure oil in the high pressure chamber 36, and the plunger 23 retracts upward.

When the plunger 23 retracts to the rising end, the variable pressure chamber 32 of the directional control valve 21 communicates with the low pressure chamber 30, so that the variable pressure chamber 32 and the variable pressure chamber 7 of the cylinder 1 are decompressed, and the piston 3 moves to the lower pressure receiving surface 6 The high pressure oil in the high pressure chamber 8 for pushing up starts the retreat.

At this time, the convertible valve element 44 of the pilot valve 40 is attached to the back pressure detection mechanism.
When the first switching passage 18A is held in a closed state by turning to the neutral position by 49 (see FIG. 5), the piston 3
When the lower pressure-receiving surface 6 of is displaced into the main pilot chamber 10,
The high-pressure oil in the high-pressure chamber 8 flows into the main pilot chamber 10 through the high-pressure oil passage 13, and further flows into the variable pressure chamber 29 of the directional control valve 21 through the pilot flow passage 17 and the variable pressure flow passage 28.
The plunger 23 starts to move downward by the high pressure oil in the variable pressure chamber 29 that pushes down the upper pressure receiving chamber 23g, and moves to the vibrating end (see FIG. 2). Therefore, in this case, the lower pressure receiving surface 6 of the piston 3 is
Moves reciprocally between the high pressure chamber 8 and the main pilot chamber 10, and the time when the lower pressure receiving surface 6 is displaced into the main pilot chamber 10 becomes the retracted end of the piston 3, and the piston 3 has the lower pressure receiving surface 6 It moves back and forth repeatedly with the longest moving stroke l1.

Further, the back pressure detecting mechanism 49 is operated to rotate the rotatable valve body 44,
The first switching channel 18A is the second switching channel 18B and the third switching channel 18B.
C or the state in which it is communicated with the fourth switching passage 18D, the lower pressure receiving surface 6 of the piston 3 which has started to retract from the advancing end is located in the first sub pilot chamber 11A and the second sub pilot chamber 11B. At the time of displacement into the third sub pilot chamber 11C, the high pressure oil in the high pressure chamber 8 passes through the high pressure oil passage 13 into the first sub pilot chamber 11A and the second sub pilot chamber 11B.
Each flows into the third sub pilot chamber 11C,
High pressure oil flows into the main pilot chamber 10 from the second switching channel 18B, the third switching channel 18C or the fourth switching channel 18D through the convertible channel 45 and the first switching channel 18A, and the high pressure oil of the switching valve 21 is discharged. Flowing into the variable pressure chamber 29, the plunger 23 starts moving downward and moves to the moving end. Therefore, the lower pressure receiving surface 6 of the piston 3 has the high pressure chamber 8, the first sub pilot chamber 11A, and the second sub pilot chamber 11
B, reciprocating movement between the third auxiliary pilot chamber 11C and the piston 3 moving stroke of the lower pressure receiving surface 6 l1, l2, l3, l
Repeatedly move back and forth at 4.

Therefore, the back pressure change in the return oil passage 55 when the return oil passage 55 is opened / closed by the opening / closing passage mechanism 56 becomes an output signal, and the back pressure detecting mechanism 49 is actuated to control the movement stroke of the piston 3 in four stages. Can be changed to

Therefore, the back stroke detection mechanism 49 can be operated and controlled by a simple control circuit in which the opening / closing mechanism 56 is connected in the middle of the return pipe 55, and the movement stroke of the piston 3 can be easily and accurately changed. There is an effect that a hydraulic circuit for converting the pressure can be simplified and a control circuit for controlling the operation of the back pressure detecting mechanism 49 can be simplified.

Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. In this embodiment, instead of the hydraulic oil passage 53 of the first embodiment, a hydraulic oil passage 60 communicating with the high pressure flow passage 15 is provided. A three-port two-position switching valve 61 is connected to the hydraulic oil passage 60. The switching valve 61 has two switching passages 18A, 18A of the cylinder 1.
It is connected to E via flow paths 62A and 62B, respectively.

On the other hand, in the middle of the return oil passage 55, a change in the oil pressure in the return oil passage 55 is detected between the return passage 25 and the switching mechanism 56, and this change in the oil pressure is output as an output signal for operating the switching valve 61. A back pressure detector 58 such as a pressure switch or a pressure sensor is connected for conversion, and the back pressure detector 58 passes through an electric self-holding circuit 59 such as a flip-flop or a shift register and the coil portion of the switching valve 61. Connected to the switching valve 61, the back pressure detector 58,
The self-holding circuit 59 constitutes a back pressure detection mechanism.

Then, when the return oil passage 55 is closed by the opening / closing mechanism 56, the back pressure in the return oil passage 55 rises, and the back pressure detector 58 detects this back pressure rise and transmits an output signal to the switching valve 61. The switching valve 61 is switched so that the high pressure oil is selectively supplied to both the switching flow paths 18A and 18E.

Therefore, the switching valve 61 is controlled by the on / off control of the switching mechanism 56.
Can be operated to change the movement stroke of the piston 3 in two stages.

In the third embodiment shown in FIG. 9, the four ports 65A, 65B, 65C and 65D of the rotary valve 64 are connected to the high pressure oil flow path and have the rotating member 66 that works in conjunction with the back pressure detecting mechanism 67. 4 connected to each and in parallel to the return oil passage 55
Hydraulic actuators 68A, 68B, 68C, 68D are provided in the middle of the two flow paths 69A, 69B, 69C, 69D, respectively, and the back pressure detection mechanism 67 is operated once to four times by the switching operation of the switching path mechanism 56 to rotate. The member 66 is rotationally controlled in four directions, and high pressure oil is selectively supplied to the four hydraulic actuators 68A to 68D to operate any hydraulic actuators 68A to 68D.

The other operations and effects of the second embodiment and the third embodiment are almost the same as those of the first embodiment, and thus the description thereof will be omitted.

(Effect of the Invention) According to the present invention, the change of back pressure in the hydraulic oil passage when the return oil passage is closed by the opening / closing mechanism is used as an output signal to control the transmission member of the back pressure detecting mechanism accurately and smoothly. In addition, since only the flow path of the return oil is controlled and a dedicated control circuit is not required, the hydraulic control circuit for controlling the operation of the control mechanism can be simplified.

Further, since the opening / closing path mechanism is installed in the middle of the return oil path connected to the return tank at the remote position, the opening / closing path of the return oil path can be remotely operated.

Also, when transmitting control signals to various control devices, a digital signal is generated by turning the switching mechanism on and off with a pulse signal, and an analog signal is generated by gradually closing the return oil passage by the switching mechanism. It is possible to diversify the manner of transmitting the control signal transmitted to the control device, such as transmitting the control signal.

[Brief description of drawings]

1 to 6 show a first embodiment of the present invention. FIG. 1 is a vertical sectional view of a hydraulic breaker showing a state at the time of starting the advance of a piston, and FIG. 2 is a start of retreating a piston. Longitudinal sectional view of the hydraulic breaker showing the state at the time, FIG. 3 is an enlarged longitudinal sectional view of the directional control valve, FIG. 4 is an enlarged longitudinal sectional view of the pilot valve, and FIG.
4 is a sectional view taken along line X1-X1 in FIG. 4, FIG. 6 is a sectional view taken along line X2-X2, FIG. 7 is a longitudinal sectional view of a hydraulic breaker showing a second embodiment of the present invention, and FIG. Hydraulic Circuit Diagram, FIG. 9 is a hydraulic circuit diagram showing a third embodiment. 49,67 …… Back pressure detection mechanism 55 …… Return oil passage 56 …… Open / close circuit mechanism

Claims (1)

[Claims] 1. A return passage connected to a remote return tank is provided with an opening / closing mechanism for opening and closing the return passage, and a hydraulic oil passage communicated with the return passage is provided at the tip thereof. Installs a back pressure detection mechanism having a transmission member that is actuated and controlled by a change in back pressure in the hydraulic oil passage when the return oil passage is opened and closed by the opening and closing passage mechanism to operate the control mechanism. A signal transmission device in a characteristic hydraulic circuit.