JP2011179191A - Hydraulic drive unit for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic drive unit for a construction machine with a simple and compact constitution of a hydraulic circuit, which enables depressurizing operation of attachment-driving piping. <P>SOLUTION: A manually-operated selector valve 39 is interposed between lines 37a and 37b of the attachment-driving piping, which connect an attachment-driving actuator 22 or 23 and an attachment-driving control valve 33. The selector valve 39 is switched to any one of the following switching positions: a switching position X to make an actuator port A and a valve port B communicate with each other and to block a piping port C and a tank port D; a switching position Y to make the actuator port A and the tank port D communicate with each other and to block the valve port B and the piping port C; and a switching position Z to make the piping port C and the tank port D communicate with each other and to block the actuator port A and the valve port B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a construction machine in which an attachment such as a crusher or a breaker is exchanged and mounted, and more particularly, to a hydraulic drive apparatus for a construction machine suitable for pressure-removing work of an attachment drive pipe.

  A hydraulic excavator, which is one of construction machines, is generally provided with a lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a boom, an arm, And an articulated working machine including a bucket. The hydraulic drive device of this hydraulic excavator includes, for example, a hydraulic pump driven by a prime mover such as an engine, and a plurality of actuators driven by pressure oil from the hydraulic pump (specifically, a traveling motor, a turning motor, a boom Cylinders, arm cylinders, bucket cylinders, etc.), hydraulic pilot control valves that control the flow of pressure oil from the hydraulic pump to the actuators, and the operation of the operating lever or pedal And operating means for outputting the generated operating pilot pressure to the corresponding control valve.

  In addition, hydraulic excavators can be used for various purposes. Instead of the standard attachment buckets, optional excavators include crushers, crushers, mowers, mowers, etc. An auger (digger) can be installed. Attachment actuators such as crushers and breakers have built-in attachment drive actuators.To cope with such attachments, recent hydraulic excavators are equipped with attachment drive pipes that can be connected to the attachment drive actuators. A hydraulic pilot type attachment control valve connected to the attachment driving actuator via the attachment driving piping and controlling the flow of pressure oil from the hydraulic pump to the attachment hydraulic actuator is provided in advance (for example, Patent Documents) 1).

No. 6-37087

  For example, when replacing the attachment attached to the hydraulic excavator from the crusher to the breaker, the crusher drive actuator is removed from the attachment drive pipe, and the breaker drive actuator is attached to the attachment drive pipe. At this time, if the pressure oil is confined in the attachment driving pipe, the pressure oil is ejected from the pipe when the pipe is removed. Moreover, even if a one-touch coupler (quick coupler) is provided at the end of the attachment driving pipe for the purpose of preventing the scattering of pressure oil, it is difficult to remove and install the pipe due to the pressure oil in the pipe. Therefore, it is necessary to perform a pressure releasing operation for returning the pressure oil in the attachment driving pipe to the tank in advance, and simplification of the configuration for realizing this has been an issue.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic drive device for a construction machine that can perform a pressure relief operation of an attachment drive pipe with a simple and compact hydraulic circuit configuration.

  (1) To achieve the above object, according to the present invention, when a hydraulic pump driven by a prime mover and an attachment incorporating an attachment driving actuator are mounted on a construction machine, the hydraulic pump changes to the attachment driving actuator. An attachment drive control valve that controls the flow of pressure oil, and a first attachment drive pipe and a second attachment drive pipe that are respectively connected between the attachment drive actuator and the attachment drive control valve. A manual switching valve interposed in the first attachment driving pipe, wherein the switching valve is connected to the attachment drive via the first attachment driving pipe. Actuator port connected to actuator A valve port connected to the attachment drive control valve via the first attachment drive pipe, a pipe port connected to the second attachment drive pipe via a branch pipe, and a tank port connected to the tank A first switching position that communicates the actuator port and the valve port and shuts off the piping port and the tank port, and communicates the actuator port and the tank port with each other and the valve port and the piping. The second switching position for blocking the port and the third switching position for connecting the piping port and the tank port to each other and blocking the actuator port and the valve port are switched.

  In the present invention, for example, when a crusher is mounted on a construction machine as an attachment incorporating an oil supply bidirectional (double-acting) attachment drive actuator, the switching valve is switched to the first switching position. Thereby, the attachment drive control valve controls the flow of the pressure oil from the hydraulic pump to the attachment drive actuator according to the operation of the operation means (in detail, the first and second attachment drive pipes). The pressure oil from the hydraulic pump is supplied to the attachment driving actuator via one of the first and second attachment driving pipes, and the pressure oil from the attachment driving actuator is returned to the tank via the other). The attachment driving actuator can be driven to open and close the crusher. When removing the crusher, the switching valve is switched to the second switching position so that the pressure oil in the first actuator driving pipe is returned to the tank to perform depressurization work. By switching to the switching position, the pressure oil in the second actuator driving pipe is returned to the tank to perform the pressure releasing operation. For example, when the breaker is mounted on the construction machine as an attachment having an actuator for driving the oil supply in one direction (single-acting type), the switching valve is switched to the second switching position. Thereby, the attachment drive control valve controls the flow of pressure oil from the hydraulic pump to the attachment drive actuator in accordance with the operation of the operation means (more specifically, for attachment drive via the first attachment drive pipe With one side of the actuator communicating with the tank, supply the hydraulic oil from the hydraulic pump to the attachment driving actuator via the second attachment driving pipe) to drive the attachment driving actuator and drive the breaker Can be made. And when removing a breaker, the pressure oil in 2nd attachment drive piping is returned to a tank by switching a switching valve to the 3rd switching position, and a pressure release operation | work is performed. Therefore, in the present invention, it is possible to perform the pressure relief operation of the attachment driving hydraulic piping with a simple and compact hydraulic circuit configuration.

  (2) In the above (1), preferably, the switching valve has a rotary operation type manual operation lever, and restricts a rotation operation range of the manual operation lever so that the first, second, and third A fixing pin and a detachable bolt for positioning to an operation position corresponding to each of the switching positions are provided.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure release operation | work of attachment drive piping can be performed with a simple and compact hydraulic circuit structure.

It is a side view showing the structure of the hydraulic excavator to which the present invention is applied, and shows a case where a crusher is attached as an optional attachment. It is a partial enlarged side view of a hydraulic excavator showing a case where a breaker is mounted as an optional attachment. It is a circuit diagram showing the principal part structure of the hydraulic drive device of the hydraulic shovel in one Embodiment of this invention. It is a top view showing the structure of the switching valve in one embodiment of the present invention, and a sectional view by section SS.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view showing the structure of a small hydraulic excavator to which the present invention is applied, and shows a case where a crusher is attached as an optional attachment. Hereinafter, when the operator is seated in the driver's seat with the excavator shown in FIG. 1, the front side (left side in FIG. 1), rear side (right side in FIG. 1), left side (paper surface in FIG. 1). The front side) and the right side (back side toward the paper surface in FIG. 1) are simply referred to as front side, rear side, left side, and right side.

  In FIG. 1, a hydraulic excavator includes a lower traveling body 2 having left and right crawler belts 1, an upper revolving body 3 that is turnably mounted on the upper portion of the lower traveling body 2, and an upper revolving body 3. A swivel frame 4 that forms the lower part of the foundation, a swing post 5 that is pivotally attached to the front part of the swivel frame 4 so as to be pivotable in the horizontal direction, and can be pivoted up and down (to be able to be lifted and lowered) on the swing post 5. An attached articulated front work machine 6, a canopy-type cab 7 provided on the left side of the revolving frame 4, and a plurality of covers 8 that cover most of the revolving frame 4 other than the cab 7 It has.

  The lower traveling body 2 rotates a substantially H-shaped track frame 9, left and right drive wheels 10 rotatably supported near the rear ends of the left and right sides of the track frame 9, and the left and right drive wheels 10. Left and right traveling motors 11 and left and right driven wheels (idlers) 12 that are rotatably supported in the vicinity of the left and right front ends of the track frame 9 and are respectively rotated by the driving force of the driving wheels 10 via the crawler belt 1. I have.

  On the front side of the track frame 9, a blade 13 for earth removal is provided so as to be movable up and down, and the blade 13 is moved up and down by a blade cylinder (not shown). Further, a turning wheel (not shown) is provided between the center portion of the track frame 9 and the turning frame 4, and the turning frame 4 is disposed with respect to the track frame 9 on the radially inner side of the turning wheel. A turning motor (not shown) for turning is provided.

  The swing post 5 is rotatable in the horizontal direction with respect to the swing frame 4 via a vertical pin (not shown). Then, the swing post 14 is rotated in the horizontal direction by the swing cylinder 14, whereby the front work machine 6 is swung left and right.

  The front work machine 6 includes a boom 15 that is rotatably connected to the swing post 5, an arm 16 that is rotatably connected to the distal end of the boom 15, and a pivot that is rotatable to the distal end of the arm 16. And a crusher 17 as an optional attached attachment. The boom 15, the arm 16, and the crusher 17 are rotated by a boom cylinder 18, an arm cylinder 19, and an attachment rotation cylinder 20. The crusher 17 can be replaced with a bucket (not shown) which is an attachment of standard equipment, or a breaker 21 (see FIG. 2) which is an attachment of other optional equipment.

  The crusher 17 incorporates an oil supply bidirectional type (double-acting type) crusher drive actuator 22 (see FIG. 3 described later), and the crusher 17 is opened and closed by the actuator 22. The breaker 21 incorporates an oil supply unidirectional (single-acting) breaker drive actuator 23 (see FIG. 3 described later), and the breaker 21 is driven by the actuator 23. An attachment drive pipe (details will be described later) that extends along the boom 15 and the arm 16 is connected to the crusher drive actuator 22 or the breaker drive actuator 23 when the attachment such as the crusher 17 or the breaker 21 is attached. Has been.

  The driver's cab 7 is provided with a driver's seat (seat) 24 on which the driver is seated. In front of the driver's seat 24, left and right traveling operation levers 25 that can be operated by both hands and feet for driving the left and right traveling motors 11 to move the hydraulic excavator forward or backward are provided. An attachment drive for driving an attachment by driving an actuator for driving an attachment (specifically, for example, a crusher opening / closing actuator 22 or a breaker drive actuator 23) on the left foot portion of the left traveling operation lever 25. Operating pedal 26 (see FIG. 3 to be described later) is provided, and the swing cylinder is driven at the right foot portion of the right traveling operating lever 25 to swing the swing post 5 (in other words, the entire front work machine 6). A swing operation pedal (not shown) for swinging the left and right is provided.

  On the left side of the driver's seat 24, the above-mentioned turning motor is driven by operating the left or right side to turn the upper turning body 3 to the left or right side, and the arm cylinder 19 is operated by operating the front side or the rear side. A cross operation type operating lever 27 that drives and dumps or cloudes the arm 16 and a lock lever 29 for preventing an erroneous operation capable of shutting off the original pressure from the pilot pump 28 (see FIG. 3 described later) are provided. On the right side of the driver's seat 24, the attachment rotating cylinder 20 is driven by operating the left or right side to rotate the attachment downward or upward, and the boom cylinder 18 is operated by operating the front or rear side. A cross operation type operation lever (not shown) for driving and lowering or raising the boom 15 and a blade operation lever 30 for driving the blade cylinder and moving the blade 13 up and down are provided.

  The left and right crawler belts 1, the upper swing body 3, the swing post 5, the blade 13, the boom 15, the arm 16, and the attachment (specifically, the crusher 17 or the breaker 21) are included in the hydraulic drive device provided in the hydraulic excavator. It is operated by.

  FIG. 3 is a circuit diagram showing a main part configuration related to attachment driving and the like in the hydraulic drive device of the hydraulic excavator in one embodiment of the present invention. Fig.4 (a) is a top view showing the structure of a switching valve, FIG.4 (b) is sectional drawing by the cross section SS in Fig.4 (a).

  3, 4 (a), and 4 (b), the hydraulic drive device includes a plurality of main hydraulic pumps 32 and pilot pumps 28 (only one is shown in FIG. 3) driven by the engine 31. A hydraulic pilot attachment that controls the flow of pressure oil from the main hydraulic pump 28 to the crusher driving actuator 22 or the breaker driving actuator 23 when the attachment such as the crusher 17 or the breaker 21 is attached to the front work machine 6. A drive control valve 33 and a hydraulic pilot type operation device 34 having an operation pedal 26 for instructing driving of the crusher 17 or the breaker 21 are provided. The hydraulic drive device includes a hydraulic pilot type arm control valve 35 that controls the flow of pressure oil from the main hydraulic pump 32 to the arm cylinder 19 as shown in the figure. A plurality of hydraulic pilot-type controls that respectively control the flow of pressure oil from 32 to the left and right traveling motors 11, blade cylinders, turning motors, swing cylinders 14, boom cylinders 18, and attachment rotation cylinders 20. It has a valve.

  The attachment drive control valve 33 and the arm control valve 35 are of a center bypass type. In this embodiment, the attachment drive control valve 33 and the arm control valve 35 are connected in series via the center bypass flow path 36. Yes. The attachment drive control valve 33 is connected to the crusher drive actuator 22 or the breaker drive actuator 23 via the attachment drive pipes 37a, 37b and 38.

  Although not shown in detail in the operating device 34, the operating pilot pressure (secondary pilot pressure) P1 obtained by reducing the original pressure (primary pilot pressure) from the pilot pump 26 according to the operating direction and operating amount of the operating pedal 26 or It has a pair of pressure reducing valves that output P2. When the operation pilot pressure P1 from the operation device 34 is output to the pressure receiving portion 33a of the attachment drive control valve 33, the attachment drive control valve 33 is switched to the upper operation position in the drawing, When the operation pilot pressure P2 is output to the pressure receiving portion 33b of the attachment drive control valve 33, the attachment drive control valve 33 is switched to the lower operation position in the figure. As a result, the crusher driving actuator 22 or the breaker driving actuator 23 is driven.

  Here, as a major feature of the present embodiment, a manual switching valve 39 is interposed in the attachment driving pipes 37a and 37b. The switching valve 39 is formed with a housing 40 having an actuator port A, a valve port B, a piping port C, and a tank port D, and a communication hole 41a for communicating any two of the ports A to D with each other. And a rotary operation type manual operation lever 42 connected to the valve body 40. The actuator port A is connected to the attachment driving actuator 22 or 23 via the attachment driving pipe 37a, the valve port B is connected to the attachment driving control valve 33 via the attachment driving pipe 37b, and the piping port C is The attachment driving pipe 38 is connected via a branch pipe 43, and the tank port D is connected to the tank 44.

  The switching valve 39 is switched to one of the switching positions X, Y, and Z according to the rotation operation of the manual operation lever 42. For example, at the operation position (operation angle θ = 0 °) of the manual operation lever 42 shown in FIG. 4A, the operation position is switched to the switching position X so that the actuator port A and the valve port B communicate with each other, and the piping port C and the tank port. Is designed to shut off. When the manual operation lever 42 is rotated 90 ° counterclockwise (in other words, at the operation angle θ = 90 °) as indicated by the solid arrow in FIG. 4A, the actuator port is switched to the switching position Y. A and the tank port D are communicated with each other, and the valve port B and the piping port C are shut off. Further, when 90 ° counterclockwise is operated as indicated by the dotted line arrow in FIG. 4 (a) (in other words, at the operation angle θ = 180 °), the position is switched to the switching position Z, and the piping port C and the tank port D are switched. The actuator port A and the valve port B are shut off while communicating with each other.

  In addition, the housing 40 is provided with two fixing pins 45a and 45b for limiting the rotational operation range of the manual operation lever 42 to θ = 0 ° to 180 °, and further bolts for limiting θ = 90 ° (details) For example, a butterfly bolt 46 is detachably provided. That is, the manual operation lever 45 can be positioned at the operation angle θ = 0 ° to 180 ° by the fixing pin 45a. When the bolt 46 is attached, the manual operation lever 45 can be positioned at the operation angle θ = 90 °, and by removing the bolt 46, the manual operation lever 45 can be operated at the operation angle θ = 180 °. Further, the manual operation lever 45 can be positioned at the operation angle θ = 180 ° by the fixing pin 45b.

  Next, the operation of this embodiment will be described.

  For example, when the crusher 17 is attached to the front working machine 6 of the excavator, the switching valve 19 is switched to the switching position X. As a result, the attachment drive control valve 33 controls the flow of pressure oil from the main hydraulic pump 32 to the crusher drive actuator 22 according to the operation of the operation pedal 26 (specifically, attachment drive pipes 37a and 37b). And the pressure oil from the main hydraulic pump 32 is supplied to the crusher drive actuator 22 via one of the attachment drive pipes 38, and the pressure oil from the crusher drive actuator 22 is returned to the tank 44 via the other). The crusher driving actuator 22 can be driven to open and close the crusher 17. When the crusher 17 is removed, the switching valve 19 is switched to the switching position Y so that the pressure oil in the actuator driving pipe 37a is returned to the tank 44 to perform depressurization, and the switching valve 19 is switched to the switching position. By switching to Z, the pressure oil in the actuator driving pipe 38 is returned to the tank 44 to perform the pressure releasing operation. In this way, the pressure release operation can be performed in stages.

  For example, when the breaker 21 is attached to the front working machine 6 of the hydraulic excavator, the switching valve 19 is switched to the switching position Y. As a result, the attachment drive control valve 33 controls the flow of pressure oil from the main hydraulic pump 32 to the breaker drive actuator 23 in accordance with the operation of the operation pedal 26 (specifically, via the attachment drive pipe 37a). With one side of the breaker drive actuator 23 communicating with the tank 44, the pressure oil from the main hydraulic pump 32 is supplied to the breaker drive actuator 23 via the attachment drive pipe 38), and the breaker drive actuator 23 And the breaker 21 can be driven. When removing the breaker 21, the switching valve 19 is switched to the switching position Z, so that the pressure oil in the attachment driving pipe 38 is returned to the tank 44 to perform the pressure releasing operation.

  As described above, in the present embodiment, it is possible to perform the pressure relief operation of the attachment driving pipe with a simple and compact hydraulic circuit configuration. Further, the switching valve 39 can be easily incorporated into an existing hydraulic excavator and can be easily applied.

  In the above-described embodiment, the hydraulic drive device includes the operation device 34 having a pressure reducing valve that outputs the operation pilot pressure P1 or P2 according to the operation direction and the operation amount of the operation pedal 26. The operation pilot pressure P1 or P2 is output to the pressure receiving portion 33a or 33b of the attachment drive control valve 33 as an example, but the present invention is not limited to this. In other words, any attachment drive control valve other than the mechanical operation method is meaningful in applying the present invention, and does not depart from the technical idea of the present invention. As one of such modifications, an operation device having a potentiometer that outputs an electric operation signal according to an operation direction and an operation amount of the operation pedal 26 is provided, and an electromagnetic proportionality is based on the electric operation signal from the operation device. The pressure reducing valve may generate the operation pilot pressure P1 or P2 and output it to the pressure receiving portion 33a or 33b of the attachment drive control valve 33.

  In the above-described embodiment, a hydraulic excavator has been described as an application target of the present invention. However, the present invention is not limited to this. That is, you may apply to a hydraulic crane, a bulldozer, etc., for example. In this case, the same effect as described above can be obtained.

17 Crusher 21 Breaker 22 Crusher Drive Actuator 23 Breaker Drive Actuator 31 Engine 32 Main Hydraulic Pump 33 Attachment Drive Control Valve 37a, 37b Attachment Drive Pipe (First Attachment Drive Pipe)
38 Attachment drive piping (second attachment drive piping)
39 Switching valve 42 Manual operation lever 43 Branch piping 44 Tank 45a Fixing pin 45b Fixing pin 46 Bolt A Actuator port B Valve port C Piping port D Tank port X to Z Switching position

Claims (2)

A hydraulic pump driven by a prime mover, and an attachment drive control valve that controls the flow of pressure oil from the hydraulic pump to the attachment drive actuator when an attachment incorporating the attachment drive actuator is mounted on a construction machine; In the hydraulic drive device for a construction machine, comprising a first attachment drive pipe and a second attachment drive pipe respectively connected between the attachment drive actuator and the attachment drive control valve,
A manual switching valve interposed in the first attachment driving pipe;
The switching valve includes an actuator port connected to the attachment driving actuator via the first attachment driving pipe, a valve port connected to the attachment driving control valve via the first attachment driving pipe, A pipe port connected to the second attachment driving pipe via a branch pipe; and a tank port connected to a tank, wherein the actuator port and the valve port communicate with each other, and the pipe port and the tank port A first switching position where the actuator port and the tank port are communicated with each other, a second switching position where the valve port and the piping port are blocked, and the piping port and the tank port are communicated with each other. The actuator port and Serial hydraulic drive system for a construction machine, characterized in that switching to one of the third switching position to block the valve port.   2. The hydraulic drive device for a construction machine according to claim 1, wherein the switching valve includes a rotary operation type manual operation lever, and restricts a rotation operation range of the manual operation lever to perform the first, second, and second operations. A hydraulic drive device for a construction machine, comprising a fixing pin and a detachable bolt for positioning at an operation position corresponding to each of the three switching positions.

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