JP3126571B2 - Fluid circuit for working cylinder of civil engineering construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid circuit for operating a working cylinder such as a bucket cylinder mounted on a civil engineering construction machine, for example, a hydraulic shovel.

[0002]

2. Description of the Related Art In general, civil engineering and construction machines, for example, hydraulic excavators are used for excavating earth and sand, consolidating soil, pile driving, and the like. Such operations include the boom, arm, and bucket of the hydraulic excavator. Activate the cylinder as appropriate to scoop up the soil or sand from the bucket,
This is done by pressing a stake. Here, as described above, if the bucket hits a large stone while excavating earth and sand, high-frequency vibration is applied to the bucket to increase the excavating force. It is empirically known that you can dig,
It is known that these operations can be performed quickly and satisfactorily by applying high-frequency vibrations to the bucket even when consolidating the ground, driving a pile, or shaking off the earth and sand adhering to the bucket.

[0003]

However, in the conventional civil engineering construction machine, the working cylinders, that is, the boom cylinder, the arm cylinder, and the bucket cylinder are merely connected to the fluid source and the discharge source via control valves. Therefore, there has been a problem that the piston rods of these cylinders only protrude and retract smoothly with a large stroke, but cannot vibrate at a high frequency.

An object of the present invention is to provide a hydraulic circuit for a working cylinder of a civil engineering construction machine, which has a simple structure and can reliably vibrate the working cylinder at a high frequency.

[0005]

SUMMARY OF THE INVENTION The purpose of the invention is as follows.
A working cylinder of a civil engineering construction machine having therein a cylinder chamber partitioned into a head side chamber and a rod side chamber by a piston, a switching valve connected to a fluid source and a discharge source,
A supply / discharge passage for connecting the switching valve to the head side chamber of the working cylinder and supplying fluid from the fluid source to the head side chamber or discharging fluid from the head side chamber to the discharge source by switching the switching valve; The other which connects the rod side chamber of the working cylinder to the one supply / discharge passage and supplies fluid from a fluid source to the rod side chamber or discharges fluid from the rod side chamber to the discharge source by switching a switching valve. Supply and discharge passages, a state where the one connection passage and the fluid source are interposed between the pair of connection passages and the fluid source and the discharge source, and the other connection passage and the discharge source are connected to each other; A switching means for alternately and repeatedly switching at a high frequency between a connection passage and a discharge source and a state in which the other connection passage and a fluid source are connected to each other; A control valve connection passage is connected, with one communicating passage for connecting the control valve with the head side chamber of the working cylinder and a control valve and the rod side of the working cylinder connected,
The control valve communicates with the other supply / discharge passage, and connects the connection passage and the communication passage between the normal position and the other supply / discharge passage. Secondly, the piston is partitioned into the head side chamber and the rod side chamber by the piston by the working cylinder fluid circuit of the civil engineering construction machine which can be located at the connection passage, the vibration position which communicates the communication passage with each other while blocking the passage. A working cylinder of an earth-moving construction machine having a cylinder chamber therein, a switching valve connected to a fluid source and a discharge source, and a switching valve connected to a head side chamber of the working cylinder. One supply / discharge passage for supplying fluid to the head side chamber or discharging fluid from the head side chamber to a discharge source, and connecting the switching valve and the rod side chamber of the working cylinder to the one supply / discharge passage The other supply / discharge passage which supplies a fluid from the fluid source to the rod side chamber or discharges the fluid from the rod side chamber to the discharge source by switching the switching valve, and a pair of connection passages, a fluid source, and a discharge source. Between the one connection passage and the fluid source and between the other connection passage and the discharge source, and between the one connection passage and the discharge source and between the other connection passage and the fluid source. A switching means for repeatedly switching at a high frequency alternately to a state in which the control valve is interposed in the middle of one of the supply and discharge passages, and a control valve to which the pair of connection passages are connected, a head side chamber and a control valve of a working cylinder. And a communication path connecting the rod side of the working cylinder and the control valve, and the other communication path paired with the one communication path, wherein the control valve includes one supply / discharge passage. Communicate Both for a working cylinder of a civil engineering construction machine, which can be located in a normal position in which a connection passage and a communication passage are cut off, and a vibration position in which one of the supply and discharge passages is cut off and the connection passage and the communication passage communicate with each other. This can be achieved by a fluid circuit.

[0006]

Now, for example, it is assumed that the working cylinder is a bucket cylinder of a hydraulic shovel (civil engineering machine), and the bucket is rotated by the working cylinder to excavate earth and sand. At this time, the high-pressure fluid from the fluid source flows into the head-side chamber of the working cylinder through the switching valve and one supply / discharge passage,
While moving the piston to the protruding side, the low-pressure return fluid flowing out of the rod-side chamber of the working cylinder is discharged to the discharge source through the other supply / discharge passage, the control valve in the normal position, and the switching valve. In such a state, when the bucket collides with a large stone and excavation cannot be easily performed, the control valve is switched to the vibration position, the other supply / discharge passage is interrupted halfway, and the connection passage and the communication passage are connected to each other. Communicate. At this time, the switching means is configured such that the one connection passage is connected to the fluid sources and the other connection passage is connected to the discharge sources, and the one connection passage is connected to the discharge sources and the other connection passage is connected to the fluid sources. And the state is alternately and repeatedly switched at a high frequency, so that one connecting passage, one communicating passage, the head side chamber of the working cylinder, and the other connecting passage, the other communicating passage, the rod side chamber of the working cylinder alternately. Is repeatedly supplied with a high-pressure fluid from a fluid source. As a result, the fluid force toward the projecting side and the retracting side repeatedly acts on the piston of the working cylinder, and as a result, the piston vibrates back and forth at a high frequency while moving to the projecting side, i.e., the bucket presses the stone at a high frequency. It will vibrate. As a result, the excavating force of the bucket increases, and even large stones can be easily excavated. Here, when the control valve is switched to the vibration position in the same manner as described above while the bucket is performing the compaction, the bucket vibrates while performing the compaction, and the compaction can be performed quickly and well. Also, when the working cylinder is an arm cylinder and the slope is solidified by a bucket, or when the working cylinder is a boom cylinder and a pile is being driven by a bucket, the control valve is switched to the vibration position as described above. Then, the pistons of these arm cylinders and boom cylinders vibrate in a state of moving to the protruding side, so that the ground consolidation and pile driving can be performed quickly and favorably.

Next, when the bucket is turned over and the scooped-up earth and sand is discharged from the bucket, the switching valve is switched to connect the fluid source to the other supply / discharge passage and the discharge source to one supply / discharge passage. The high pressure fluid from the fluid source is supplied to the rod side chamber of the working cylinder, the return fluid from the head side chamber is discharged to the discharge source, and the piston is moved to the retracted side. Here, when the soil is soft and a large amount of soil adheres to the bucket, high frequency vibration is applied to the bucket in order to shake off the adhered earth and sand. In this case, Switching the control valve from the normal position to the vibration position,
The other supply / discharge passage is shut off so that the fluid from the fluid source cannot be supplied to the rod side chamber of the working cylinder, and the high pressure fluid is alternately and repeatedly supplied at a high frequency to the rod side chamber and the head side chamber of the working cylinder through the communication passage. The piston is vibrated at a high frequency back and forth around the stop position. As a result, the earth and sand adhering to the bucket is reliably shaken off. When the control valve is switched from the normal position to the oscillating position when the switching valve is switched to the neutral position and the high-pressure fluid from the fluid source is not supplied to the rod side chamber of the working cylinder, the piston is moved in the same manner as described above. It is possible to vibrate at high frequency back and forth around the stop position. As described above, the vibration function is given to the already installed working cylinder, so that there is no need to install a special cylinder for vibration, and the structure of the fluid circuit is simplified.

Next, in the case of the fluid circuit according to the third aspect, the switching valve is switched to supply the high pressure fluid from the other supply / discharge passage to the rod side chamber of the working cylinder, and move the piston to the retracted side. When the control valve is switched from the normal position to the oscillating position, the high-pressure fluid is alternately and repeatedly supplied to the head-side chamber and the rod-side chamber of the working cylinder through the communication passage, whereby the piston vibrates back and forth at a high frequency. Accordingly, the bucket vibrates, so that even if the bucket has soil attached thereto, the soil is reliably shaken off.

Further, according to the second aspect of the present invention, it is possible to prevent the control valve from switching from the normal position to the oscillating position when the piston is moving to the retracted side. It can be specialized to apply vibration only when moving to the protruding side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a hydraulic shovel as a civil engineering construction machine.
Has a traveling frame 11 which moves forward or backward by traveling. A swing frame 13 that can swing in a horizontal plane is supported on the traveling frame 11, and a base end of a boom 15 that swings up and down by a boom cylinder 14 is connected to the swing frame 13. A base end of an arm 17 that swings up and down by an arm cylinder 16 is connected to a tip of the boom 15, and a pin is attached to a tip of the arm 17.
A bucket 19 for excavating soil and the like is connected via a cable 18. Reference numeral 20 denotes a bucket cylinder as a working cylinder whose head side is connected to the base end of the arm 17, and one end of a piston rod 21 of the bucket cylinder 20 is connected to a tip end of the arm 17 via a pin 22. The other end of the bracket 23 is connected via a pin 24. Reference numeral 25 denotes a connecting rod interposed between the bracket 23 and the bucket 19, and the proximal end of the connecting rod 25 is connected to the pin 24, and the distal end thereof is connected to the bucket 19 via the pin 26. I have. When the bucket cylinder 20 is operated, the bucket 19 swings up and down around the pin 18.

In FIG. 2, reference numeral 30 denotes a manual four-port three-position switching valve installed on the cab of the turning frame 13 of the excavator 10, and the switching valve 30 and a fluid source installed on the turning frame 13 are provided. The fluid pump 31 and the tank 32 as a discharge source are connected by a supply passage 33 and a discharge passage 34, respectively. 35 is the fluid pump 31 and tank
A suction passage connecting the suction passage 32 and a relief valve disposed between the supply passage 33 and the tank 32. The bucket cylinder 20 has a cylinder chamber 38 formed therein. The cylinder chamber 38 is slidably housed in the cylinder chamber 38 and has a piston 39 to which the piston rod 21 is connected.
The partition is divided into a head side chamber 38a and a rod side chamber 38b. The switching valve 30 and the head side chamber 38a of the bucket cylinder 20 are connected by one supply / discharge passage 41, and the switching valve
By switching 30, the fluid from the fluid pump 31 is supplied to the head side chamber 38 a or the fluid flowing out from the head side chamber 38 a is discharged to the tank 32. The switching valve 30 and the rod-side chamber 38b of the bucket cylinder 20 are connected by one supply / discharge passage 41 which is paired with the other supply / discharge passage 41. Side room 38b
Or the fluid flowing out of the rod side chamber 38b
Discharge to 32.

Reference numeral 45 denotes a fluid pump as a fluid source connected to a tank 47 via a suction passage 46. A supply passage is provided between the fluid pump 45 and a manual three-port two-position switching valve 48.
The relief valve 50 is interposed between the supply passage 49 and the tank 47. Reference numeral 53 denotes switching means, and the switching means 53 and the switching valve 48
A pilot-type flow control valve 55 (or a pilot-type flow control valve) is interposed in the middle of the supply path 54. In a supply path 54 between the switching valve 48 and the flow control valve 55, a branch path 57 in which a pilot-type flow control valve 56 (or a pilot-type flow control valve may be interposed) is provided. One end is connected, and the other end of the branch path 57 is connected to the switching means 53. These flow control valves 55 and 56 are connected to a fluid motor 75 to be described
The fluid from 45 is adjusted so as to flow in advance.
Reference numeral 60 denotes a discharge path connecting the switching means 53 to the tank 61 serving as a discharge source, and reference numerals 62 and 63 denote a pair of connection paths connected to the switching means 53. As a result, the switching means 53 is interposed between the pair of connection passages 62 and 63 and the fluid pump 45 and the tank 61. The state where the pumps 45 are connected to each other and the other connection passage 63 and the tank 61 are connected to each other, and the state where the one connection passage 62 and the tank 61 are connected to each other and the other connection passage 63 and the fluid pump 45 are connected to each other alternately at a high frequency. Switch.

FIGS. 2, 3, 4, 5, 6, 7, 8, 9, 1
In FIGS. 0, 11, and 12, the switching means 53 has an intermediate block 69 that is housed in the housing hole 68 of the case body 67 and has a shorter axial length than the housing hole 68. A valve chamber 70 having a circular cross section is formed extending toward. In the storage hole 68 on the base end side of the intermediate block 69, a disk-shaped partition plate 72 in which a connection hole 71 penetrating in the center is formed is disposed, and in the storage hole 68 on the base end side of the partition plate 72. Accommodates a disk-shaped fixing plate 73. Here, the fixing plate 73 is a partition plate 72
, And as a result, the storage hole 68 between the partition plate 72 and the fixing plate 73 becomes a space, and forms the motor chamber 74. As a result, the motor chamber 74 and the valve chamber 70 are connected via the connection hole 71.

An internal gear type fluid motor 75 is housed in the motor chamber 74. The fluid motor 75 has a substantially cylindrical internal gear having a plurality of, here five, internal teeth 76 formed on its inner periphery. 77
And the internal teeth of the internal gear 77
A plurality of external teeth 78, which is one less than the internal teeth 76, are formed in mesh with the external gears 79, and the external gears 79 eccentrically rotate (revolve) about the axis of the internal gear 77. At the center of the gear 79, a penetrating spline hole 81 having a spline internal tooth 80 on the inner periphery is formed. 82 is a storage hole
68 is a cover for closing the base opening of the case 68, and the cover 82 is fixed to the base end of the case body 67. Reference numeral 84 denotes a pin that passes through the intermediate block 69, the partition plate 72, the internal gear 77, and the fixed plate 73.
It is inserted and fixed to 67 and cover 82, respectively. As a result, the intermediate block 69, the partition plate 72, the internal gear 77,
The fixing plate 73 is fixed while being prevented from rotating by the case body 67 and the cover 82. The above-described case body 67, intermediate block 69, partition plate 72, fixing plate 73, and cover 82 as a whole have a motor chamber 74 therein.
A casing 85 in which a valve chamber 70 coaxial with the motor chamber 74 and a connection hole 71 connecting the motor chamber 74 and the valve chamber 70 are formed.
Is configured.

A thrust bearing 88 and a cylindrical rotary valve body 90 having a through hole 89 formed therein are housed in the valve chamber 70. The rotary valve body 90 is provided with an internal gear 77 of a fluid motor 75.
And can rotate around the axis while maintaining the coaxial relationship. Further, spline internal teeth 91 are formed on the inner periphery of the through hole 89 of the rotary valve body 90. Reference numeral 95 denotes a connecting rod passing through the connecting hole 71. The connecting rod 95 has a distal end inserted into the through hole 89 and a proximal end inserted into the spline hole 81. The spline external teeth 96 formed on the outer periphery of the distal end of the connecting rod 95 mesh with the spline internal teeth 91, and the spline external teeth 97 formed on the base outer circumference mesh with the spline internal teeth 80. By
The connecting rod 95 connects the rotary valve body 90 and the external gear 79 of the fluid motor 75. When the external gear 79 rotates eccentrically, the connecting rod 95 transmits the rotation of the external gear 79 to the rotary valve element 90 while performing a precession about the tip end, and the rotary valve element 90
Rotate 90 around the axis.

Reference numeral 99 denotes a discharge annular groove formed between the inner periphery of the valve chamber 70 and the outer periphery of the rotary valve body 90, specifically, formed in the outer periphery of the rotary valve body 90 and extending continuously in the circumferential direction. A communication hole 100 extending in the radial direction communicating with the through hole 89 is provided on the bottom of the groove 99.
Are formed. Reference numeral 101 denotes a discharge hole whose one end is opened at the outer periphery of the center of the connecting rod 95, and the other end of the discharge hole 101 is opened at the base end surface of the connecting rod 95. Reference numeral 102 denotes a discharge passage formed in the casing 85, specifically, in the fixed plate 73 and the cover 82, one end of which communicates with the spline hole 81 and the other end of which is opened on the outer periphery of the cover 82. Is connected to the discharge path 60. The discharge passage 102 extends from the discharge annular groove 99 to the communication hole 100 and the through hole 8.
9. The fluid flowing out to the spline hole 81 through the discharge hole 101 is discharged from the switching means 90 to the tank 61. Reference numerals 104 and 105 denote first and second supply annular portions provided between the inner periphery of the valve chamber 70 and the outer periphery of the rotary valve body 90, here, on the outer periphery of the rotary valve body 90 on both axial sides of the discharge annular groove 99. Grooves, these first,
The second supply annular grooves 104 and 105 both extend continuously in the circumferential direction. 106 is inside the casing 85, specifically the intermediate block
69, a partition plate 72, an internal gear 77, a fixed plate 73, and a first supply passage formed in the cover 82. One end of the first supply passage 106 communicates with the first supply annular groove 104,
The other end is open to the outer periphery of the cover 82. The other end opening of the first supply passage 106 is connected to the branch passage 57, whereby the first supply passage 106 is connected to the fluid pump 45.
Can be supplied to the first supply annular groove 104. 108 is inside the casing 85, specifically the middle block
69, a partition plate 72, an internal gear 77, a fixed plate 73, and a cover 82.
The second supply passage 108 is arranged at a predetermined angle in the circumferential direction from the second supply passage 108. One end of the second supply passage 108 communicates with the second supply annular groove 105, and the other end is opened to the outer periphery of the cover 82. I have. Then, the other end opening of the second supply passage 108 is connected to the supply passage 54, whereby the second supply passage 108 can supply the fluid from the fluid pump 45 to the second supply annular groove 105.

Reference numeral 110 denotes a plurality of first grooves formed on the outer periphery of the rotary valve body 90 at equal distances in the circumferential direction.
The concave groove 110 extends in the axial direction from the first supply annular groove 104 toward the discharge annular groove 99. 111 is a plurality of second concave grooves formed on the outer periphery of the rotary valve body 90 at equal distances in the circumferential direction,
These second grooves 111 extend in the axial direction from the second supply annular groove 105 toward the discharge annular groove 99. 112 is a rotary valve
While being formed on the outer circumference of 90 at equal distances in the circumferential direction,
A plurality of third grooves alternately arranged in the circumferential direction with the first grooves 110; these third grooves 112 extend in the axial direction from the discharge annular groove 99 toward the first supply annular groove 104; ,
The distal end portion of the first supply annular groove 104 close to the discharge annular groove 99 of the first concave groove 110 circumferentially overlaps with the distal end portion of the first concave groove 110. Reference numeral 113 denotes a plurality of fourth grooves formed on the outer periphery of the rotary valve body 90 at equal intervals in the circumferential direction and alternately arranged with the second grooves 111 in the circumferential direction. 113
Extends in the axial direction from the discharge annular groove 99 toward the second supply annular groove 105, and the distal end near the second supply annular groove 105 is formed around the distal end of the second concave groove 111 near the discharge annular groove 99. Overlap in the direction.

Reference numeral 116 denotes a plurality of supply / discharge passages formed in the casing 85, specifically, the intermediate block 69 and the partition plate 72 at equal circumferential intervals, here the same number of internal teeth 76 of the internal gear 77, One end of these supply / discharge passages 116 is connected to the first,
An opening is formed on the inner periphery of the valve chamber 70 so as to face the overlapping portion between the third concave grooves 110 and 112, and the other ends are the internal gear 77 and the external gear 79.
Between the internal teeth 76. These supply / discharge passages 116 supply the fluid from the first groove 110 to the fluid chamber 117 or supply the fluid from the fluid chamber 117 to the third
The fluid is discharged into the concave groove 112. 119 and 120 are casing 85
Among them, more specifically, a plurality of, here two, guide passages formed in the intermediate block 69 at a distance in the circumferential direction, and one end of each of the guide passages 119 and 120 has a second groove 111 and a fourth groove 113.
An opening is formed on the inner periphery of the valve chamber 70 so as to face the overlapped portion, and the other end is opened on the front end surface of the intermediate block 69. And these guide passages 119 and 120 are the second concave grooves 1
In addition to guiding the fluid from 11, the fluid is guided to the fourth groove 113.

Referring to FIGS. 2 and 3, a control valve 124 is provided in the case body 67 at the end side of the intermediate block 69.
The control valve 124 is formed in the case body 67 and has a cap
A spool chamber 125 extending in the radial direction, one end of which is closed by 126, a spool 127 movably housed in the spool chamber 125, and the other end of the spool 127 and the other end surface (bottom surface) of the spool chamber 125 And a spring 128 as an elastic body which is interposed therebetween and biases the spool 127 toward one end. Then, first, second, third, and fourth lands 129, 130, 131, and 132 are sequentially formed from one end to the other end of the spool 127. As a result, the first, second, and third lands are formed. , 4th land 1
1st, 2nd, 3rd annular grooves 1 between 29, 130, 131, 132
33, 134 and 135 are provided.

The switching means 5 is provided in the case body 67.
3.Specifically, a pair of passages whose base ends are respectively connected to the guide passages 119 and 120 are formed, and these passages are the above-described connection passages 62 and 63, and these connection passages 62, 63
The distal end of 63 is connected to the control valve 124, and more specifically, is opened at a central portion in the axial direction of the spool chamber 125 so as to be spaced apart in the axial direction.
137 is formed in the case body 67, and one end is connected to the connection passages 62, 6
3 and the other end of the case body 67
The first passage opened on the outer periphery of the case body 138 is the case body 67
A second end of which is opened in the spool chamber 125 having one end facing the first passage 137 and the other end opened in the tip end face of the case body 67.
These first and second passages 137 and 138 constitute a part of the other supply / discharge passage 42. As a result, the control valve 124 is interposed in the other supply / discharge passage 42. Third and 139 and 140 are formed in the case body 67, and have one end opened to the spool chamber 125 facing the connection passages 62 and 63, and the other end opened to the tip end surface of the case body 67.
The third and fourth passages 139 and 140 are paired communication passages each having one end connected to the control valve 124 and the other end connected to one of the supply and discharge passages 41 and 42. 1
Part of 41, 142. As a result, one communication passage
141 connects the head side chamber 38a of the bucket cylinder 20 to the control valve 124 via one supply / discharge passage 41, and the other communication passage 142 connects the bucket cylinder 20 via the other supply / discharge passage 42.
Is connected to the control valve 124. Also, 143 is a casing 85, specifically the case body 6
7. A fifth passage formed in the cover 82, one end of which is open to the spool chamber 125 on one end side of the connection passages 62 and 63, and the other end of which is open to the outer periphery of the cover 82. Pilot passage 144 connecting switching valve 48 and control valve 124
A part of. When the switching valve 48 is switched to the flow position, the high-pressure fluid discharged from the fluid pump 45 flows into the spool chamber 125 on one side from one end face of the spool 127 through the pilot passage 144, and the other fluid flows into the spool 127. Apply fluid force toward the side. As a result, spool 1
27 moves to the other side against the spring 128, and the control valve 124 is switched from the normal position T to the vibration position S. Here, when the switching valve 124 is located at the normal position T, the first and second passages 137 and 138, that is, the other supply / discharge passage
42 communicates through the third annular groove 135 of the spool 127, and connects to the connection passages 62, 63 and the communication passages 141, 142 (third,
The fourth passages 139, 140) are shut off by the third and second lands 131, 130 of the spool 127, respectively. On the other hand, when the switching valve 124 is located at the vibration position S, the first and second passages 137, 140 138, that is, the other supply / discharge passage 42 is the spool 1
27 are blocked by the third land 131, and the connecting passages 62, 63
And the communication passages 141 and 142 (third and fourth passages 139 and 140) communicate with the spool 127 through the second and first annular grooves 134 and 133, respectively. Reference numeral 150 denotes an air vent hole formed in the case body 67.

Next, the operation of the first embodiment of the present invention will be described. Now, it is assumed that the earth and sand is dug up by the bucket 19 of the excavator 10. At this time, the switching valve 30
Has been switched to the cross flow position while the control valve 124
Is located at the normal position T, communicates with the other supply / discharge passage 42, and blocks connection passages 62, 63 and communication passages 141, 142. As a result, the high-pressure fluid discharged from the fluid pump 31 flows into the head-side chamber 38a of the bucket cylinder 20 through the switching valve 30 and one of the supply / discharge passages 41, and moves the piston 39 and the piston rod 21 to the protruding side, and the bucket 19 Is turned to the excavation side as described above. At this time, the low-pressure return fluid that has flowed out of the rod-side chamber 38b of the bucket cylinder 20 passes through the other supply / discharge passage 42, the switching valve 30, and the discharge passage 34 which communicate with the control valve 124 because the control valve 124 is at the normal position T, and the tank 32 Is discharged.

If the bucket 19 hits a large stone and cannot be easily excavated during such excavation, the switching valve 48 is switched from the shut-off position to the flow position, and the high-pressure fluid discharged from the fluid pump 45 is discharged. It is led to one end of a spool 127 of the control valve 124 through a pilot passage 144 (fifth passage 143), and the spool 127 is
Move to the other side against 128. This allows the control valve
The switch 124 is switched from the normal position T to the vibration position S, and the other supply / discharge passage 42 is interrupted halfway by the third land 131, while the connection passages 62, 63 and the communication passages 141, 142 are connected to the second and first passages. They are communicated through the annular grooves 134 and 133, respectively.

When the switching valve 48 is switched to the flow position, the high-pressure fluid from the fluid pump 45 is supplied to the first and second supply passages through the supply passage 54, the branch passage 57, and the first and second supply passages 106 and 108. It is supplied to the annular grooves 104 and 105. At this time, a certain supply / discharge passage 116 is inserted into the first groove 110,
Communicate with the second groove 111, the remaining supply / discharge passage 116 communicates with the third groove 112, and the guide passage 120 communicates with the fourth groove 111.
Assuming that they are in communication with the respective 113, high-pressure fluid is supplied from the first supply annular groove 104 to a part of the fluid chamber 117 of the fluid motor 75 through the aforementioned supply / discharge passage 116. Thus, the external gear 79 of the fluid motor 75 receives driving force from the inflowing fluid and rotates eccentrically (revolves) about the axis of the internal gear 77. At this time, the external gear 79 has only one tooth. Since many internal gears 77 are engaged with each other, the external gear 79 also rotates around its own axis in addition to revolving. Here, connecting rod 95
The spline external teeth 96 and 97 of the fluid motor 75 mesh with the spline internal teeth 91 and 80 of the external gear 79, respectively, so that the rotational driving force based on the rotation of the external gear 79 of the fluid motor 75 causes precession. The rotation is transmitted to the rotary valve body 90 through the connecting rod 95, and the rotary valve body 90 is rotated around the axis. At this time,
The return fluid is pushed out from the remaining portion of the fluid chamber 117 of the fluid motor 75 to the remaining supply / discharge passage 116, and this fluid is supplied to the third groove 1
12, discharge annular groove 99, communication hole 100, through hole 89, discharge hole 10
1. Discharged to the tank 61 through the discharge passage 102 and the discharge passage 60. On the other hand, the high-pressure fluid supplied to the second supply annular groove 105 is supplied to the guide passage 119, the connection passage 62, and the second annular groove of the control valve 124.
134, communication passage 141 (third passage 139), one supply / discharge passage
41 to the head side chamber 38a of the bucket cylinder 20 and the rod side chamber 38b of the bucket cylinder 20.
Are the other supply / discharge passage 42, the communication passage 142 (the fourth passage 140),
First annular groove 133 of control valve 124, connection passage 63, guide passage 1
20, fourth concave groove 113, discharge annular groove 99, communication hole 100, through hole
89, the discharge hole 101, the discharge passage 102, and the discharge passage 60 are discharged to the tank 61. As a result, the high-pressure fluid from the fluid pump 45 flows into the head-side chamber 38a of the bucket cylinder 20 in addition to the high-pressure fluid from the fluid pump 31 that is constantly supplied, and the piston 39 and the piston rod 21 are slightly more than usual. Protrude a lot.

Next, when the rotary valve element 90 slightly rotates by receiving the rotational driving force from the fluid motor 75, the supply / discharge passage 1
The communication between the first groove 16 and the first and third concave grooves 110 and 112 is displaced in the circumferential direction, and the position where the high-pressure fluid is supplied is moved in the circumferential direction, whereby the external gear 79 of the fluid motor 75 is moved in the same direction. Continue spinning. At this time, the return fluid discharged from the fluid motor 75 is also discharged to the discharge annular groove 99, the discharge passage 102, and the discharge passage 60.
Through the tank 61. On the other hand, due to the rotation of the rotary valve body 90 described above, the guide passage 119 which has been in communication with the second groove 111 up to now has the guide passage 120 which has been in communication with the fourth groove 113 and the fourth groove 113. Is connected to the second concave groove 111, and the high-pressure fluid from the fluid pump 45 is supplied to the second supply annular groove 105, the guide passage 120, the connection passage 63, and the first of the control valves 124.
The rod-side chamber 38b of the bucket cylinder 20 passes through the annular groove 133, the communication passage 142 (the fourth passage 140), and the other supply / discharge passage 42.
It will flow into. At this time, the bucket cylinder 20
The head side chamber 38a is connected to the tank 61,
The fluid in 38a is supplied to one of the supply / discharge passage 41, the communication passage 141, the second annular groove 134 of the control valve 124, the connection passage 62, the guide passage 119,
4th concave groove 113, discharge annular groove 99, communication hole 100, through hole 89,
Tank 61 through discharge hole 101, discharge passage 102, discharge passage 60
Is discharged. As a result, the pressure in the head-side chamber 38a of the bucket cylinder 20 decreases even though the high-pressure fluid is supplied from the fluid pump 31, and the pressure in the rod-side chamber 38b becomes high, and the piston 39 and the piston rod 21 are slightly retracted. .

Next, when the rotary valve element 90 is further rotated slightly in the same direction by the fluid motor 75, the supply / discharge passage 116 and the first
The form of communication with the third grooves 110 and 112 is further shifted in the circumferential direction, and the second groove 111 is provided in the guide passage 119 and in the fourth groove 113.
Communicates with the guiding passages 120, respectively.
The high-pressure fluid from the fluid pump 45 flows into the head-side chamber 38a of the bucket cylinder 20. Thus the switching valve
When the switch 48 is switched to the flow position, the one connection passage 62 and the fluid pump 45 are connected to each other, and the other connection passage 63 and the tank 61 are connected to each other, and the one connection passage 62 and the tank 61 are connected to each other. At the same time, the other connection passage 63 and the state in which the fluid pumps 45 are connected to each other are alternately and repeatedly switched at a high frequency, so that one connection passage 62 and one communication passage 1
41, the high-pressure fluid from the fluid pump 45 is alternately supplied to the head side chamber 38a of the bucket cylinder 20, the other connection passage 63, the other communication passage 142, and the rod side chamber 38b of the bucket cylinder 20 alternately. As a result, the bucket cylinder 20
The fluid force toward the projecting side and the retracting side repeatedly acts on the piston 39, and as a result, the piston 39 vibrates back and forth at a high frequency while moving to the projecting side. As a result, the bucket 19 vibrates at a high frequency while being pressed against the stone, thereby increasing the excavating force, and even if the bucket 19 hits a large stone,
This can be easily excavated. Here, the piston 39 and the bucket 19 are hydraulic excavators.
In order not to cause resonance with the hydraulic excavator 10, the hydraulic excavator 10 is caused to vibrate at a high frequency exceeding a resonance frequency to some extent. When a large stone is dug up in this way, the switching valve 48
Is switched from the flow position to the shut-off position, and the control valve 124 is switched from the vibration position S to the normal position T so that only the fluid from the fluid pump 31 is supplied to the bucket cylinder 20.

When the bucket 19 scoops the earth and sand, the revolving frame 13 is appropriately rotated, the boom cylinder 14 and the arm cylinder 16 are appropriately operated, and the bucket 19 is moved to just above the discharge position. Next, the bucket 19 is turned over to discharge the scooped earth and sand from the bucket 19. In this case, the switching valve 30 is switched to the parallel flow position, and the fluid pump 31 is connected to the other supply / discharge passage 42. At the same time, the tank 32 and one supply / discharge passage 41 are connected, and the high pressure fluid from the fluid pump 31 is supplied to the rod side chamber 38b of the bucket cylinder 20 at the other supply / discharge passage 42, the normal position T.
Through the control valve 124 to move the piston 39 and the piston rod 21 to the retracted side. At this time, the low-pressure return fluid flowing out of the head-side chamber 38a of the bucket cylinder 20 is discharged to the tank 32 through one supply / discharge passage 41.

In the course of such reversal, if the picked-up soil is soft and adheres to the bucket 19 in a large amount, an operation of shaking off the attached soil from the bucket 19 is performed. In such cases, the bucket
When 19 is rotated to an appropriate position, the switching valve 48 is switched from the shut-off position to the flow position, and the control valve 124 is switched from the normal position T to the vibration position S. As a result, the other supply / discharge passage 42 that has been supplying high pressure to the rod-side chamber 38b of the bucket cylinder 20 is now connected to the third land 1 of the spool 127 of the control valve 124.
The fluid is interrupted on the way by 31 and the fluid from the fluid pump 31 cannot be supplied to the rod side chamber 38b. At this time, the high-pressure fluid from the fluid pump 45 is alternately and repeatedly supplied to the head-side chamber 38a and the rod-side chamber 38b of the bucket cylinder 20 through the communication passages 141 and 142 at a high frequency by the same operation of the switching means 53 as described above. As a result, the piston 39 does not move to the projecting side as described above, but vibrates back and forth at a high frequency around the stopped position, and
It shakes off the earth and sand. Note that such a swing-down operation can also be performed by switching the switching valve 30 to the neutral position and then switching the switching valve 48 to the flow position after the piston 39 reaches the stroke end on the retracted side. As described above, since the vibration function is provided to the already installed bucket cylinder 20, there is no need to install a special cylinder for vibration, and the structure of the fluid circuit is simplified. Then, when the work of shaking off the soil is completed, the switching valve 48 is switched from the flow position to the shut-off position.

FIG. 13 is a diagram showing a second embodiment of the present invention. In this embodiment, a pilot passage 153 for connecting the other supply / discharge passage 42 and the control valve 124 between the switching valve 30 and the control valve 124 is added to the first embodiment. Specifically, although not shown, the first
A passage extending from the other end of the spool 127 to the spool chamber 125 on the other side is formed in the middle of the passage 137, and the air vent hole 150 is omitted. When such a pilot passage 153 is provided, when the other supply / discharge passage 42 has a high pressure, the high-pressure fluid in the other supply / discharge passage 42 is supplied to the control valve.
Since it is supplied to 124 and acts on the other end of the spool 127,
The control valve 124 is fluidly locked in the normal position T. As a result, the control valve 124 can be prevented from switching from the normal position T to the vibration position S when the piston 39 is moving to the retracted side, and the fluid circuit is moved only when the piston 39 is moved to the protruding side. Can be specialized to impart vibration.

FIG. 14 is a view showing a third embodiment of the present invention. In this embodiment, the communication passage 141 is not connected in the middle of one of the supply / discharge passages 41, but is directly connected to the head side chamber 38a of the bucket cylinder 20, and the connection position is set to the connection position of the one supply / discharge passage 41. The position is almost half a lap away from In this way, when the switching valve 30 is switched to the cross flow position, the high-pressure fluid discharged from the fluid pump 31 is once supplied to the head side chamber 38a of the bucket cylinder 20.
Can be flowed into. The other configuration and operation are the same as in the second embodiment.

FIG. 15 is a diagram showing a fourth embodiment of the present invention. In this embodiment, one supply / discharge passage 1 connecting the switching valve 30 and the head-side chamber 38a of the bucket cylinder 20 1
A control valve in which a pair of connection passages 62 and 63 are connected in the middle of 55 1
When the control valve 156 is located at the normal position T, the control valve 156 communicates with one of the supply / discharge passages 155 and shuts off the connection passages 62, 63 and the communication passages 141, 142. In addition, when it is located at the vibration position S, one of the supply / discharge passages 155 is shut off, and the connection passages 62, 63 and the communication passages 141, 142 are communicated with each other. With this configuration, when the switching valve 30 is switched to the cross flow position, the high-pressure fluid is supplied from the fluid pump 31 to the rod-side chamber 38b of the bucket cylinder 20, and the piston 39 moves to the retracting side, The earth and sand adhering to the bucket 19 can be quickly and reliably shaken off. That is, at this time, the control valve 156 is moved to the normal position T.
To the vibration position S, and the connection passages 62 and 63 and the communication passage
The high pressure fluid discharged from the fluid pump 45 is alternately and repeatedly supplied to the head side chamber 38a and the rod side chamber 38b of the bucket cylinder 20 by the switching means 53, thereby moving the piston 39 to the retracted side. It vibrates with high frequency back and forth in the state where it is made to occur. As a result, the bucket 19 vibrates, and the earth and sand adhering to the bucket 19 are quickly and reliably shaken off. Other configurations,
The operation is the same as in the second embodiment. In this embodiment, when the switching valve 30 is switched to the parallel flow position to supply fluid to the head side chamber 38a of the bucket cylinder 20 and move the piston 39 to the projecting side, that is, when the bucket 19
When the soil is excavated, the switching valve 48 is switched to the flow position and the control valve 156 is moved from the normal position T to the vibration position S.
However, since the high-pressure fluid in one supply / discharge passage 155 is guided to the control valve 156 through the pilot passage 153 and the control valve 156 is fluidly locked at the normal position T, the switching to the vibration position S is performed. It will not be replaced. However,
When the pilot passage 153 is omitted, as described above, the control valve 156 is switched to the vibration position S, and the piston 39 of the bucket cylinder 20 does not move to the protruding side or the retracting side, and moves forward and backward at the stop position. Vibrates.

FIG. 16 is a diagram showing a fifth embodiment of the present invention. In this embodiment, the communication passage 142 is directly connected to the rod-side chamber 38b of the bucket cylinder 20, and the other supply / discharge passage 157 is connected to the rod-side chamber 38b at a position approximately half a distance from the communication passage 142. In this way, the high-pressure fluid from the fluid pump 31 can be once flowed into the rod-side chamber 38b of the bucket cylinder 20.

In the above-described embodiment, the bucket
Although the bucket 19 is made to vibrate when excavating a large stone by the use of the bucket 19, in the present invention, the bucket 19 is vibrated.
The bucket 19 may be vibrated when the consolidation is performed by the consolidation 19 so that the consolidation can be performed quickly and satisfactorily. Also,
In the present invention, the working cylinder is
When the slope 19 is being compacted by the bucket 19, the piston of the arm cylinder 16 may be vibrated to quickly and satisfactorily perform the compaction of the slope, or the working cylinder may be the boom cylinder 14. When the stakeout is being performed by the bucket 19, the piston of the boom cylinder 14 may be vibrated so that the stakeout is quickly and satisfactorily performed. At this time, since two boom cylinders 14 are usually provided, two sets of the above-described fluid circuits may be provided in parallel, and these two boom cylinders 14 may be separately controlled. One fluid circuit as described above may be provided, and the two boom cylinders 14 may be controlled collectively by branching from the middle. Further, in the above embodiment, the fluid pump 3
1, 45 and the tanks 32, 47, 61 are separate bodies, but may be collectively formed as one fluid pump and tank.

[0033]

As described above, according to the present invention, the working cylinder can be reliably vibrated at a high frequency with a simple structure.

[Brief description of the drawings]

FIG. 1 is a schematic overall front view showing a state in which a first embodiment of the present invention is applied to a hydraulic shovel.

FIG. 2 is a circuit diagram thereof.

FIG. 3 is a front sectional view of the switching means.

FIG. 4 is a plan view of the switching means.

FIG. 5 is a sectional view taken along the line AA of FIG. 3;

FIG. 6 is a sectional view taken along the line BB in FIG. 3;

FIG. 7 is a sectional view taken along the line CC of FIG. 3;

8 is a sectional view taken along the line DD in FIG.

FIG. 9 is a sectional view taken along the line EE in FIG. 3;

FIG. 10 is a sectional view taken along the line FF in FIG. 3;

FIG. 11 is a sectional view taken along the line GG of FIG. 3;

FIG. 12 is a sectional view taken along the line HH of FIG. 3;

FIG. 13 is a circuit diagram of a second embodiment of the present invention.

FIG. 14 is a circuit diagram near a control valve showing a third embodiment of the present invention.

FIG. 15 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 16 is a circuit diagram near a control valve showing a fifth embodiment of the present invention.

[Explanation of symbols]

 20 ... Work cylinder 30 ... Switching valve 31,45 ... Fluid source 32,47,61 ... Discharge source 38 ... Cylinder chamber 38a ... Head side chamber 38b ... Rod side chamber 39 ... Piston 41,155 ... One supply / discharge passage 42,157 ... The other supply / discharge passage 53 ... switching means 62, 63 ... connection passage 124 ... control valve 141 ... one communication passage 142 ... other communication passage 153 ... pilot passage T ... normal position S ... vibration position

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F15B 21/12 E02F 9/22 E02F 3/42 F15B 11/00

Claims (3)

(57) [Claims] 1. A working cylinder of an earth-moving construction machine having a cylinder chamber partitioned by a piston into a head side chamber and a rod side chamber, a switching valve connected to a fluid source and a discharge source, and a switching valve and a working cylinder. One supply / discharge passage for connecting the head side chamber to supply the fluid from the fluid source to the head side chamber or discharging the fluid from the head side chamber to the discharge source by switching the switching valve, and the switching valve and the rod side chamber of the working cylinder. A pair with the one supply / discharge passage, and the other supply / discharge passage for supplying fluid from the fluid source to the rod side chamber or discharging fluid from the rod side chamber to the discharge source by switching the switching valve, A pair of connecting passages and a fluid source,
A state in which the one connection passage and the fluid source are connected to each other and the other connection passage and the discharge source are connected to each other, and the one connection passage and the discharge source and the other connection passage and the fluid source A switching means for alternately switching at a high frequency alternately to a connected state, a control valve interposed in the middle of the other supply / discharge passage, and a control valve to which the pair of connection passages are connected; One communication passage connecting the control valve, and the other communication passage pairing the one communication passage connecting the rod side of the working cylinder and the control valve, the control valve being connected to the other communication passage. It can be located at a normal position where the supply / discharge passage is communicated and the connection passage and the communication passage are cut off, and at a vibration position where the other supply / discharge passage is cut off and the connection passage and the communication passage communicate with each other. Features Working cylinder fluid circuit of civil engineering and construction machinery. A pilot passage for guiding fluid in the other supply / discharge passage between the switching valve and the control valve to the control valve, wherein when the pressure in the other supply / discharge passage is high, the high pressure is applied. The fluid circuit for a working cylinder of a civil engineering construction machine according to claim 1, wherein the control valve is fluidly locked in a normal position. 3. A working cylinder of an earth-moving machine having a cylinder chamber partitioned into a head side chamber and a rod side chamber by a piston, a switching valve connected to a fluid source and a discharge source, and a switching valve and a working cylinder. One supply / discharge passage for connecting the head side chamber to supply the fluid from the fluid source to the head side chamber or discharging the fluid from the head side chamber to the discharge source by switching the switching valve, and the switching valve and the rod side chamber of the working cylinder. A pair with the one supply / discharge passage, and the other supply / discharge passage for supplying fluid from the fluid source to the rod side chamber or discharging fluid from the rod side chamber to the discharge source by switching the switching valve, A pair of connecting passages and a fluid source,
A state in which the one connection passage and the fluid source are connected to each other and the other connection passage and the discharge source are connected to each other, and the one connection passage and the discharge source and the other connection passage and the fluid source A switching means for alternately and repeatedly switching at a high frequency to a connected state, a control valve interposed in the middle of one supply / discharge passage, and a control valve to which the pair of connection passages are connected; and a head-side chamber of a working cylinder. One communication passage connecting the control valve to the control valve, the other communication passage pairing the one communication passage connecting the rod side of the working cylinder and the control valve, and the control valve includes one communication passage. It can be positioned at a normal position where the supply / discharge passage is communicated and the connection passage and the communication passage are cut off, and at a vibration position where one supply / discharge passage is cut off and the connection passage and the communication passage communicate with each other. Features Working cylinder fluid circuit of civil engineering and construction machinery.