JP4486141B2 - Automatic control device for tilt angle of cargo handling equipment in construction machinery vehicles - Google Patents

Description

  The present invention relates to a loading / unloading work machine such as a bucket / fork that supports a load in a loading / unloading construction machine vehicle such as a bucket loader that equips a vehicle body with a loading / unloading work machine in which a work unit is moved up and down by a lifting boom. When the lift boom is raised by turning upward, in order to maintain the ground posture of the load handling work machine in a substantially horizontal position, the load work work machine is rotated with respect to the lift boom. It is related with the improvement about the inclination-angle automatic control apparatus of the material handling work machine operated so that it may incline and rotate in the opposite direction.

  A construction machine vehicle for cargo handling such as a bucket loader that equips a vehicle body with a working machine for lifting and lowering operation will be described in the form of a bucket loader. Normally, as shown in FIG. A lift boom 2 provided with a fulcrum shaft S on a front end side of a vehicle body 1 mounted with a power source a such as a hydraulic device driven by an engine and mounted in a long girder shape on the front and rear thereof, A front end side protruding forward of the vehicle body 1 is pivoted so as to freely move up and down about the fulcrum shaft S that is pivotally fitted to the base end side, and a longitudinal intermediate portion of the lift boom 2 and the vehicle body 1 The lift cylinder LC that extends and contracts by the pressure oil guided from the hydraulic device of the power source a mounted on the vehicle body 1 is placed between the lift boom 2 and the lift boom 2 by the operation of the lift cylinder LC. This lift boo The bucket 3 for loading and unloading is pivotally supported at the tip of 2 so as to freely rotate forward and backward (left and right in the figure) with respect to the lift boom 2 by a bucket pin 30 inserted through a bracket provided at the bottom. A bucket cylinder BC provided on the front surface side of the vehicle body 1 is connected to a bracket provided on the rear surface side of the bucket 3 via a link mechanism 4, and the bucket 3 is operated by the operation of the bucket cylinder BC. The configuration is such that it is pivoted back and forth about the center.

  In this form of construction machine vehicle, the cargo handling bucket 3 in which the load is accommodated is brought into a substantially horizontal posture with the opening upward as shown by the broken line a in FIG. 1 by the operation of the bucket cylinder BC. In this state, the lift boom 2 is lifted and rotated by the operation of the lift cylinder LC, and the cargo handling bucket 3 passes through the height position indicated by the broken line B in FIG. As shown in FIG. 1, the cargo handling bucket 3 is indicated by a broken line D in FIG. 1 when the bucket cylinder BC is actuated. It is used to carry out the cargo handling work by rotating the dump truck and releasing the stored cargo.

  In this cargo handling operation, when the cargo handling bucket 3 containing the cargo is raised by the upward rotation of the lift boom 2, the cargo handling bucket 3 maintains a posture in which its opening is substantially horizontal. Control to change the mounting angle with respect to the lift boom 2 is performed so as to rise.

  The cargo handling bucket 3 attached to the tip end of the lift boom 2 has a substantially horizontal posture with the opening opening facing upward at the tip end of the lift boom 2 that is descending, as shown by the broken line a in FIG. In the supported state, if the mounting angle of the cargo handling bucket 3 with respect to the lift boom 2 is kept fixed, the ground angle of the lift boom 2 fluctuates as the lift boom 2 rotates upwardly, The ground posture of the cargo handling bucket 3 supported by the lift boom 2 changes, and when the lift boom 2 stands up, the opening becomes a posture toward the rear. As a result, the fact that the load is in a liquid state is released toward the driver's seat b provided on the vehicle body 1 so that the operator sitting on the driver's seat b suffers from the head. Become.

  For this reason, the cargo handling bucket 3 attached and supported at the tip of the lift boom 2 has its mounting angle with respect to the lift boom 2, and the lift boom 2 is rotated upward so that the angle of the cargo handling bucket 3 with respect to the ground is set. It is necessary to perform change control so that the cargo handling bucket 3 is held in a horizontal posture by rotating in the opposite direction by the changed angle.

  The above-described link mechanism 4 is a mechanism that automatically controls the leveling of the cargo handling bucket 3 when the lift boom is raised and rotated.

  The link mechanism 4 is formed in a lateral balance shape in which the upper end side and the lower end side swing back and forth around the bucket link center pin shaft 41 and is disposed on the front side of the intermediate portion in the longitudinal direction of the lift boom 2. A support member in which a bucket link center pin 41 that pivotally supports the link rod 42 is attached to the lift boom 2, and the link rod 42 is connected to the lower end side of the link rod 42. The link cylinder 42 is supported by the lift boom 2 so as to move together with the lift boom 2 by being pivotally mounted on the projecting end of 4a, and the upper end side of the link rod 42 is connected to the vehicle body 1 at the base end side. By connecting the front end side of the connecting rod 43 connected to the projecting end of the piston rod of BC and the lower end side of the link rod 42 to the back side of the cargo handling bucket 3, When the lift boom 2 is rotated upward by the operation of the slider LC, the operation of the link rod 42 that rotates together, the bucket cylinder BC moves the cargo handling bucket 3 in the rotation direction of the lift boom 2. It is the thing of the structure made to rotate to a reverse direction.

  Specifically, with respect to FIG. 1, when the cargo handling bucket 3 held in the posture shown by the broken line a in FIG. 1 is raised by raising the lift boom 2 by the operation of the lift cylinder LC, The link mechanism 4 lifts the cargo handling bucket 3 at an angle corresponding to an angle obtained by tilting and rotating the ground posture of the cargo handling bucket 3 backward by the upward rotation of the lift boom 2 by operating the bucket cylinder BC. This is a mechanism that functions to rotate forward in a direction opposite to the direction in which the boom 2 rotates, thereby automatically holding the ground posture of the cargo handling bucket 3 substantially horizontally.

  In this way, the construction machinery vehicle for cargo handling incorporates a link mechanism for maintaining the working posture of the working portion substantially constant when the working portion for supporting the load is lifted and lowered by the boom that moves up and down. It is. The same applies to the case where the cargo handling work machine is a forklift in which a fork is attached to the tip of a boom that moves up and down. When the fork attached to the tip of the boom is lifted by the rotation of the boom, if the angle of the fork attached to the boom is constant, the ground posture of the fork is tilted rearward and the lifted load is placed on the driver's seat. It is because it comes to be released.

  By the way, the link mechanism provided in the construction machine vehicle for cargo handling in this way is only a large construction machine vehicle for cargo handling, and the small one is not attached because there is no space for attachment.

  In a small construction machine vehicle for cargo handling, as shown in FIGS. 2 and 3, a turning frame d is mounted on the upper surface of a vehicle body 1 driven by a traveling device 10 via a turning mechanism c that turns with a vertical turning axis. A power source a such as an engine / hydraulic device and a cabin b that houses a driver's seat and a control device are mounted on the swivel frame d, and mounting brackets are mounted on both left and right sides of the swivel frame d. e is provided, and the base end portion of the lift boom 2 is pivotally supported by a fulcrum shaft S, and between the intermediate portion of the lift boom 2 and the turning frame d, the hydraulic pressure of the hydraulic device of the power source a is provided. A lift cylinder LC that operates to extend and retract is provided so that the lift boom 2 can be moved up and down about the fulcrum shaft S by the lift cylinder LC. Bucket 3 is attached to the bucket pin 30 so as to freely rotate back and forth around the bucket pin 30, and between the cargo handling bucket 3 and the lift boom 2, the cargo handling bucket 3 is centered on the bucket pin 30 with respect to the lift boom 2. In the case of a small bucket loader configured by installing a bucket cylinder BC to be rotated back and forth, the attachment angle of the cargo handling bucket 3 is changed by the bucket cylinder BC, and the link mechanism 4 described above is used. Omits this.

  A circuit diagram constituting a hydraulic circuit for operating the lift cylinder LC for rotating the lift boom 2 shown in FIG. 4 and the bucket cylinder BC for rotating the cargo handling bucket 3 by hydraulic pressure will be specifically described. In this case, the hydraulic circuit W connected to the lift cylinder LC is a single circuit only for operating the lift cylinder LC, and the hydraulic circuit Y connected to the bucket cylinder BC is a single circuit for operating the bucket cylinder BC. It is.

  The main operation valve A provided connected to the hydraulic circuit W is an independent operation valve that only controls the operation of the lift cylinder LC by controlling the hydraulic circuit W, and is provided connected to the hydraulic circuit Y. The main operation valve B is an independent operation valve that only controls the operation of the bucket cylinder BC by controlling the hydraulic circuit Y.

  The control operation of the main operation valve A and the main operation valve B is as follows. In the main operation valve A, the pressure oil flowing from the main hydraulic power source F1 to the lift cylinder LC by the hydraulic circuit W is supplied to the hydraulic circuit W. From the feed side circuit w1 to the cylinder, the lift cylinder LC is operated to “cylinder extension”, the pressure oil flows from the return side circuit w2 to the cylinder to be operated to “cylinder contraction”, and the pressure The operation of the lift cylinder LC is controlled by switching to a “neutral” state where the oil flow is cut off and the cylinder is not operated. In the main operation valve B, the flow of pressure oil flowing from the main hydraulic source F2 to the bucket cylinder BC by the hydraulic circuit Y flows from the circuit y1 on the feed side of the hydraulic circuit Y to the cylinder. The state in which the bucket cylinder BC is operated to “cylinder extension”, the state in which the pressure oil flows from the return side circuit y2 to the cylinder and the cylinder is operated to “cylinder contraction”, and the flow of pressure oil is cut off and the cylinder is not operated. The operation of the bucket cylinder BC is controlled by switching to the “neutral” state.

  In this way, a single hydraulic circuit W and a hydraulic circuit Y are connected to the lift cylinder LC and the bucket cylinder BC, respectively, and the hydraulic circuit W and the hydraulic circuit Y are operated independently. In a small bucket loader type construction equipment vehicle for cargo handling having a configuration in which A and the main operation valve B are connected to each other, the operator operates the control lever for controlling the lift cylinder LC. Is operated to operate the main operation valve A, and when the lift boom 2 is turned up, the operation lever for controlling the bucket cylinder BC is operated to operate the main operation valve B, and the bucket cylinder BC is operated. By operating the bucket 3, the bucket 3 is tilted and rotated, thereby changing the mounting angle of the bucket 3 with respect to the lift boom 2 and correcting the ground posture of the bucket 3 to be substantially horizontal. It is in memorial.

  Therefore, an operation for changing and controlling the mounting angle of the cargo handling bucket 3 is performed by an operator located in the cabin b operating an operation lever for controlling the lift cylinder LC that operates the lift boom 2 with one hand. Then, by lifting the lift boom 2 and turning it upward, the grounding posture of the cargo handling bucket 3 that rises is visually confirmed, while the other hand, the bucket cylinder BC for changing the mounting angle of the cargo handling bucket 3 is used. By operating the control lever for controlling the load, the mounting angle of the cargo handling bucket 3 with respect to the lift boom 2 is changed so that the grounding posture of the cargo handling bucket 3 is kept substantially horizontal. Therefore, it takes a lot of practice and training to learn, so there is a problem that it is not easy to use.

  As described above, the load handling bucket is pivotally supported at the tip of the lift boom via the bucket pin of the mounting shaft so that it can be tilted back and forth, and the change control of the mounting angle of the bucket with respect to the lift boom is performed. The ground posture is roughly the mounting angle when the lifting boom is raised by rotating the lift boom upward by simply extending and retracting the bucket cylinder installed between the lifting boom and the handling bucket. In a small construction machine vehicle that does not have a lift mechanism that automatically changes and controls to be horizontal, when carrying out the cargo handling work by rotating the lift boom upward, the ground with the change in the angle of the lift arm to the ground. By changing the angle, the attitude of the bucket for cargo handling, which is inclined with respect to the ground surface, is controlled by manual operation of the bucket cylinder. Troublesome control to hold the attitude of the bucket for handling cargo almost horizontally by tilting and rotating the bucket with respect to the lift boom in an opposite direction to the rotation direction of the lift boom by an angle corresponding to the rotation angle of the lift boom. There is a problem that must be done.

  The problem to be solved in the present invention is that when the lift arm is rotated upward to perform a cargo handling operation using the cargo handling bucket, the cargo handling bucket is tilted and rotated with respect to the lift arm so as to hold the cargo handling bucket in a substantially horizontal posture. Operation control of the inclination angle of the cargo handling bucket to be performed without using a lift mechanism that requires a mounting space for attachment, without requiring a special mounting space, in conjunction with turning the lift arm, It is intended to constitute means for automatically performing a control operation for automatically rotating the cargo handling bucket into a substantially horizontal posture.

In the present invention, as means for solving the above-described problems, a lift cylinder (LC) for rotating the lift boom (2) and a bucket cylinder (BC) for rotating the cargo handling bucket (3) are substantially omitted. A hydraulic circuit ( W ) of a lift cylinder (LC) configured to have the same volume and rotating the lift boom (2), a main operation valve (A) for controlling the flow of pressure oil in the hydraulic circuit (W), A hydraulic circuit ( Y ) of a bucket cylinder (BC) for rotating the bucket for cargo handling (3), a main operation valve (B) for controlling the flow of pressure oil in the hydraulic circuit (Y), and the hydraulic circuit (W ) And the hydraulic circuit (Y), the return oil of the pressure oil supplied to the lift cylinder (LC) is supplied to the bucket cylinder (BC) and passes through the bucket cylinder (BC). A connection circuit (Z) to return to (T) ; A switching valve (5), a control valve (6) and a control valve (7) for controlling the flow of pressure oil in the connection circuit (Z), the main operation valve (A), the switching valve (5), By operating the control valve (6) and the control valve (7), the connection circuit (Z) connects the hydraulic circuit (W) and the hydraulic circuit (Y), and the bucket cylinder (BC) Interlocking means for interlocking the operation with the operation of the lift cylinder (LC), and a shutoff means for controlling connection / disconnection of the interlocking means,
The interlocking unit operates the main operation valve (A), the switching valve (5), the control valve (6), and the control valve (7), and the connection circuit (Z) is connected to the hydraulic circuit (W). wherein when to connect the hydraulic circuit (Y), when the lift boom (2) is raised rotated by the operation of the lift cylinder (LC), said bucket cylinder (BC) is the lift cylinder ( in conjunction with the operation of the LC), in approximately equal actuation amount the operation amount of the lift cylinder (LC), is pivoted the cargo handling bucket (3) in the rotational direction opposite to the direction of the lift boom (2) When the interlocking means shuts off the interlocking by the interlocking means, the lift boom (2) and the bucket cylinder (BC) can be independently operated. Automatic control of machine tilt angle It is to provide a location.
Further, in the automatic control device for the inclination angle of the cargo handling work machine in the construction machine vehicle, the main operation valve (A) is “cylinder extension” in the hydraulic circuit (W), and the flowing hydraulic oil is in the lift cylinder (LC). Any of the three states of the flow path state that flows in the direction in which the pressure oil is operated, the flow path state in which the pressure oil flows in the direction of “cylinder contraction”, and the “neutral” flow path state in which the flow of pressure oil is blocked The flow path state of the crab pressure oil can be switched , and the main operation valve (B) moves the hydraulic circuit (Y) in the direction in which the flowing pressure oil operates the bucket cylinder (BC) to “cylinder extension”. The flow path state of pressure oil is in one of three states: a flow path state that flows, a flow path state that flows in the direction in which the pressure oil operates to “cylinder contraction”, and a flow path state that blocks the flow of pressure oil. can be switched, the connection circuit (Z), the oil A connection circuit for connecting the return side circuit of the hydraulic circuit (W) to the feed side circuit of the hydraulic circuit (Y) when the circuit (W) is switched to the flow path state of “cylinder extension” (Z1) and a connection circuit (z2) for connecting a return side circuit of the hydraulic circuit (Y) to a return side circuit of the hydraulic circuit (W). A connection circuit (z3) for connecting a return-side circuit of the hydraulic circuit (W) to a feed-side circuit of the hydraulic circuit (Y) in a state in which the flow path state is switched to the “shrinkage”; A connection circuit (z4) for connecting the return side circuit of the circuit (Y) to the return side circuit of the hydraulic circuit (W) , and the switching valve (5) is a main operation valve by the interlocking means. In conjunction with the operation of (A), the hydraulic circuit (W) When the flow path state is “Da-elong”, the return oil of the pressure oil that has passed through the lift cylinder (LC) flows to the hydraulic circuit (Y) via the connection circuit (z1), and further, the bucket cylinder ( Pressure from the lift cylinder (LC) in the flow state returning from the BC to the tank (T) of the hydraulic circuit (W) via the connection circuit (z2) and the flow path state of “cylinder contraction”. The oil return oil flows to the hydraulic circuit (Y) via the connection circuit (z3), and further from the bucket cylinder (BC) to the hydraulic circuit (W) via the connection circuit (z4). And the flow state returning to the tank (T) of the hydraulic circuit (W) without pressure oil passing through the connection circuits (z1) and (z2) and the connection circuits (z3) and (z4). You can switch back to `` Neutral '' And features.
Further, in the automatic control device for the inclination angle of the cargo handling work machine in the construction machine vehicle, the main operation valve (A) is actuated by the pilot pressure oil flowing through the hydraulic pilot circuits (p1) and (p2), and the switching valve (5) is operated by pilot pressure oil flowing through hydraulic pilot circuits (p5) and (p6), and the control valve (6) and the control valve (7) are hydraulic pilot circuits (p7) and (p8), respectively. The hydraulic pilot circuit of the switching valve (5), the control valve (6) and the control valve (7) is connected to the pilot circuit of the main operation valve (A), The operation of the switching valve (5), the control valve (6) and the control valve (7) can be interlocked with the operation of the main operation valve (A), and further, the main operation valve (A ) The lift cylinder (LC) and the bucket cylinder (BC) are connected by shutting off the interlock between the pilot circuit and the hydraulic pilot circuit of the switching valve (5), the control valve (6) and the control valve (7). It can be operated independently.
Furthermore, in the automatic control device for the tilt angle of the cargo handling work machine in the construction machine vehicle, the main operation valve (A) can be operated independently by the shut-off means shutting off the interlock by manual operation. It is characterized by that.

  The means according to the present invention operates the lift cylinder that rotates the lift boom upward when the load handling bucket is raised by rotating the lift boom, and the cargo handling bucket is turned in the reverse direction. This is based on the knowledge obtained by examining the relationship with the operation of the bucket cylinder that is tilted and rotated.

  A lift boom 2 and a lift cylinder LC that rotates the boom boom 2 around the fulcrum shaft S; a cargo handling bucket 3 that is pivotally attached to the front end side of the lift boom 2 via a bucket pin 30 of an attachment shaft so as to be pivotable back and forth; If the bucket cylinder BC which rotates this is shown and it demonstrates using FIG. 4 showing the action | operation of the lift cylinder LC and the action | operation of the bucket cylinder BC, the lift boom 2 of the bucket loader of the working machine for cargo handling will be described. As shown by the solid line a on the lower end side of the figure, the cargo handling bucket 3 that is grounded to the ground surface GL on the front end side and attached to the front end side is substantially horizontal by the operation of the bucket cylinder BC. Suppose that it is in a state of being held in such a posture.

  Then, the bucket loader moves the lift boom 2 upward by approximately 90 degrees from the above-described state position by the operation of “cylinder extension” which is the push-out operation of the lift cylinder LC. It is assumed that the cargo handling operation is performed with the cargo handling bucket 3 being raised by rotating up to the state position d shown.

  In addition, the bucket cylinder BC for tilting and rotating the cargo handling bucket 3 is operated by a “cylinder extension” operation that is an extrusion operation, so that the cargo handling bucket 3 is centered on the bucket pin 30 of the mounting shaft, and the fulcrum shaft S of the lift boom 2. Inclining and turning clockwise in the direction opposite to the counterclockwise turning direction of the ascending rotation, and performing an operation of inclining and turning in a direction to correct the attitude of the cargo handling bucket 3 substantially horizontally And

  In this bucket loader, the bucket cylinder BC pushes the piston rod by the operation of “cylinder extension” and tilts and rotates the cargo handling bucket 3 around the mounting shaft 30 in the direction opposite to the rotation direction of the lift boom 2. The amount of operation of the bucket cylinder BC is as follows: when the lift boom 2 at the state position a is turned up by 30 degrees by the operation of the lift cylinder LC and the cargo handling bucket 3 is raised to the state position a. In this case, it is an operation amount that causes the cargo handling bucket 3 to be in a substantially horizontal posture by rotating it 30 degrees clockwise in the direction opposite to the counterclockwise rotation direction of the cargo handling bucket 3. When the lift cylinder LC is turned 60 degrees and turned to the state position c, the cargo handling bucket 3 is rotated clockwise in the direction opposite to the rotation direction of the lift boom 2. In addition, when the lift cylinder LC rotates the lift boom 2 90 degrees up to the state position d, the operation of rotating the cargo handling bucket 3 90 degrees in the opposite direction is performed. The amount of operation of the bucket cylinder BC substantially matches the amount of operation of the lift cylinder LC for raising and rotating the lift boom 2 to each state position.

  This means that when the lift boom 2 is raised and rotated to raise the cargo handling bucket 3 by the operation of the lift cylinder LC, the bucket cylinder BC that tilts and rotates the cargo handling bucket 3 is referred to as the lift cylinder LC. This means that the cargo handling bucket 3 will be in a substantially horizontal posture if operated to the same operating amount. Therefore, when carrying out the cargo handling operation by lifting and rotating the lift boom 2 by the operation of the lift cylinder LC, the operation amount of the bucket cylinder BC that tilts and rotates the cargo handling bucket 3 is the operation amount of the lift cylinder LC. By controlling so as to be approximately the same, the ground posture of the cargo handling bucket 3 can be automatically held in a substantially horizontal posture.

  In order to substantially match the operation amount of the lift cylinder LC and the operation amount of the bucket cylinder BC, the lift cylinder LC and the bucket cylinder BC are formed to have the same volume, and the cross-sectional area of the cylinder, which is the area of the piston, The amount of oil to be fed by ensuring that the product of the rod stroke and the axial length of the cylinder match, so that the operating amount corresponds to the amount of pressure oil to be fed. It is obtained by making them match.

  In order for the amount of oil supplied to the lift cylinder LC and the amount of oil supplied to the bucket cylinder BC to coincide with each other, the oil supplied to the lift cylinder LC is supplied to the hydraulic circuit of the cylinder. When returning to the oil tank from the return side, if the oil is returned to the oil tank through the bucket cylinder BC, the same amount of oil as that supplied to the lift cylinder LC is always supplied to the bucket cylinder BC. Thus, the same amount of oil can be supplied to the bucket cylinder BC, whereby the same operation amount can be obtained.

  Therefore, in the present invention, the above-described means is proposed as a means for solving the above-described problems.

  According to the means of the present invention, the posture of the cargo handling bucket is automatically held in a substantially horizontal posture when the cargo handling operation is performed by raising and lifting the lift boom by raising the lift cylinder by the operation of the lift cylinder. The automatic tilt angle control device for a cargo handling work machine in a construction machine vehicle is configured so that the lift cylinder and the bucket cylinder have substantially the same capacity, and the oil that has flowed to the lift cylinder flows directly to the bucket cylinder, By operating the bucket cylinder and then returning it to the oil tank, the same volume of oil will flow to the lift cylinder and bucket cylinder so that the lift cylinder and bucket cylinder operate at the same operating amount at the same time. Therefore, there is no need to use a lift mechanism that requires an installation space for installation. The cylinder and the bucket cylinder can automatically hold the grounding posture of the bucket for cargo handling during the cargo handling operation, and the posture of the cargo handling work machine can be maintained in the same manner as a large construction machine vehicle. The operation to obtain a substantially horizontal posture can be obtained by a simple operation that only performs an operation for controlling the lifting operation of the lift boom.

The automatic tilt angle control apparatus for a cargo handling machine in a construction machine vehicle according to the present invention allows the same amount of pressure oil to flow in the lift cylinder and the bucket cylinder so that the pressure oil that has flowed to the lift cylinder returns to the tank through the bucket cylinder. Thus, by making the lift cylinder operating amount and the bucket cylinder operating amount substantially the same, the angle of the cargo handling bucket in the direction opposite to the lift boom rotation direction corresponds to the lift boom rotation angle. Is a means for maintaining the posture of the cargo handling bucket substantially horizontally, and the specific configuration thereof is the conventional small bucket loader type shown in FIG. Connecting circuit z1 and z2 for connecting the hydraulic circuit W and the hydraulic circuit Y to the circuit configuration of the lift cylinder LC and the bucket cylinder BC in the construction machine vehicle of FIG. 4 and a hydraulic pilot-operated switching valve 5, a control valve 6 and a control valve 7 which are operated in conjunction with the main operation valve A are provided in a place surrounded by a chain line in FIG. In addition, an electromagnetic valve SV is provided to control connection / disconnection between the hydraulic pilot circuit of the switching valve 5, the control valve 6 and the control valve 7 of the hydraulic pilot operation and the hydraulic pilot circuit of the main operation valve A. Is.
Next, embodiments will be described in detail with reference to the drawings.

  6, 7, and 8 are circuit diagrams illustrating the hydraulic circuit configuration of the automatic level positioning device for a cargo handling work machine in a construction machine vehicle that implements the present invention. A construction machine vehicle that implements the auto level positioning device is a construction machine vehicle in the form of a small bucket loader having the configuration shown in FIGS. 6, 7, and 8, the cylinder indicated by the symbol LC is the left and right side portions of the turning frame d that is turnably mounted on the vehicle body 1 via the turning mechanism c in FIGS. 2 and 3. The left and right lift booms 2, 2 that can be pivoted up and down around the fulcrum shaft S on the upper end sides of the mounting brackets e provided respectively on the left and right lift booms 2, 2, The left and right lift cylinders LC are respectively installed between the swivel frames d, and the cylinders indicated by reference numeral BC are formed in a semi-cylindrical shape that is long on the left and right sides. The lifting buckets 2 and 2 are supported so as to be bridged between the lift booms 2 and 2, and the bucket 3 is mounted on the bucket pin 30 so that it can be tilted and rotated freely by the bucket pin 30. Move Cormorants, and the respective upper surface side of the left and right lift boom 2, between the end portions of the left and right cargo handling bucket 3 is a bucket cylinder BC of the left and right that So設 respectively.

  The lift cylinder LC and the bucket cylinder BC have substantially the same internal capacity calculated by the product of the piston surface area, which is the cross-sectional area of the cylinder, and the piston rod, which is the axial length of the cylinder. Is formed. As a result, when the lift cylinder LC is operated to incline and rotate the lift boom 2 by an angle of 30 degrees by supplying pressure oil, the same amount of oil supplied to the lift cylinder LC is supplied. When the bucket cylinder BC is fed, the bucket cylinder BC operates with the same operation amount as the operation amount of the lift cylinder LC, and the lift bucket LC has the same operation amount as the operation amount obtained by rotating the lift boom 2 by 30 degrees. It is made to operate | move by the operation amount which inclines and rotates only 30 degrees. If the operating amount when pressure oil is supplied to the cylinder to perform the operation is proportional to the amount of oil supplied to the cylinder and the amount of oil supplied to the cylinder is the same amount, This is because the same amount of work is given.

  W is a hydraulic circuit that constitutes a flow path of pressure oil that operates the lift cylinder LC, and includes a feed-side circuit w1 that feeds pressure oil to the lift cylinder LC and a return-side circuit w2 that returns the pressure oil from the cylinder LC. .

  Y is a hydraulic circuit that constitutes the flow path of the pressure oil that operates the bucket cylinder BC, and includes a feed-side circuit y1 that feeds the pressure oil to the bucket cylinder BC and a return-side circuit y2 that returns the pressure oil from the bucket cylinder BC. Become.

  Z is sent to the bucket cylinder BC when the pressure oil sent to the lift cylinder LC returns to the tank T from the circuit w1 on the feed side, and returns to the tank T after operating the bucket cylinder BC. It is a connection circuit that connects the hydraulic circuit W and the hydraulic circuit Y. When the hydraulic circuit W is in a “cylinder extension” state (the state of the circuit diagram of FIG. 7) in which the cylinder rod is pushed out by the pressure oil by the operation of the main operation valve A described later, the hydraulic circuit W The return side circuit w2 of the hydraulic circuit Y is connected to the connection circuit z1 that connects the return side circuit w2 of the hydraulic circuit Y to the return side circuit w2 of the hydraulic circuit W in the same state. The connection circuit z1 and z2 for the "cylinder extension" state with the connection circuit z2 to be connected and the hydraulic circuit W draws the cylinder rod by the pressure oil by the operation of the main operation valve A described above. ”(The state of the circuit diagram of FIG. 8), the feed side circuit w1 of the hydraulic circuit W that is switched to the return side is connected to the return side circuit y2 of the hydraulic circuit Y. The connection circuit z3 and the hydraulic circuit Y in this state For the state of "cylinder contraction" with the connection circuit z4 for connecting the feed side circuit y1 switched to the return side circuit to the feed side circuit w1 switched to the return side circuit of the hydraulic circuit W It consists of connection circuits z3 and z4.

  A shows a state in which the hydraulic circuit W that guides the pressure oil to the lift cylinder LC shuts off the flow of the pressure oil to the lift cylinder LC, and the pressure oil discharged from the pump flows into the lift cylinder LC from the circuit w1 on the feed side. In this state, the piston rod is operated to extend and return to the tank T by the return side circuit w2, and the pressure oil discharged from the pump flows into the lift cylinder LC from the return side circuit w2. The main operating valve operates to switch the flow of the pressure oil into three states: a state in which the piston rod is retracted and the state flows so as to return to the tank T by the circuit w1 on the feeding side.

  B is a main operation valve that controls the hydraulic circuit Y that constitutes the flow path of pressure oil to the bucket cylinder BC. Like the main operation valve A that controls the hydraulic circuit W described above, B is the pressure oil to the bucket cylinder BC. A state in which the flow is interrupted, a state in which the pressure oil flows into the cylinder from the feed-side circuit y1 and extends to the piston rod, and flows back to the tank T by the return-side circuit y2, and the pressure oil However, the flow of pressure oil flows into the cylinder from the return side circuit y2 and causes the piston rod to be pulled in, and the flow of the pressure oil is returned to the tank T by the feed side circuit y1. This is a main control valve that operates to switch.

  The main operation valve A and the main operation valve B may be operated by ordinary means such as a mechanical mechanism or an electric means as long as the operation described above is performed by operation of the operation lever. However, in this example, a main pilot valve for hydraulic pilot operation that is operated at the pilot pressure by applying a pilot pressure guided by a hydraulic pilot circuit to the operating portion is configured.

  In the main operation valve A, the pilot is supplied from the hydraulic power source o1 to the hydraulic pilot circuit p1 by operating the hydraulic pilot operation valve provided separately by operating the operation lever provided in the cabin b. By flowing pressure oil and applying pilot pressure to the operating portion a1 on the left end side of the main operation valve A, the spool is operated to move to the right, and the pilot pressure oil is flowed from the hydraulic source o2 to the hydraulic pilot circuit p2. By applying the pilot pressure to the actuating portion b1 on the right end side of the main operation valve A, the spool is actuated to move to the left to perform the switching operation of the hydraulic circuit W described above, and the hydraulic pilot circuits p1 and p2 When there is no inflow of pilot hydraulic pressure, the spool is held in a position where the hydraulic circuit W is disconnected from the hydraulic power source pump and tank T by a spring load. Are then refers way.

  Further, in the main operation valve B, pilot pressure oil is supplied from the hydraulic power source o3 to the hydraulic pilot circuit p3 by operating the operation lever in the same manner as the main operation valve A, and the pilot pressure of the main operation valve B is changed. By applying it to the left-hand side actuating part a2, the spool is actuated to move to the right, and pilot pressure oil is supplied from the hydraulic power source o4 to the hydraulic pilot circuit p4 so that the pilot pressure is supplied to the right end side of the main operation valve B. When applied to the operating part b2, the spool is operated so as to move to the left to switch the hydraulic circuit Y, and when there is no inflow of pilot hydraulic pressure in any of the hydraulic pilot circuits p3 and p4, the spring With the load, the spool is held at a position where the hydraulic circuit Y is cut off from the hydraulic source pump and the tank T.

  Accordingly, the main operation valves A and B are independently operated by controlling the connection of the hydraulic power source to the hydraulic pilot circuit by operating the operation lever, respectively, and the hydraulic circuit W, the hydraulic circuit Y, The lift cylinder LC and the bucket cylinder BC are individually operated by controlling each of them, and the operation is performed by the operation of “cylinder extension” in which the piston rod extends and the operation of “cylinder contraction” in which the piston rod is retracted. And act as a switch.

  5. When the lift cylinder LC is operated by the oil flowing through the hydraulic circuit W by the operation of the main operation valve A, the oil that has operated the lift cylinder LC flows to the hydraulic circuit Y through the connection circuit Z, and the bucket cylinder This is a switching valve that switches the hydraulic circuit W to a state in which the hydraulic circuit W is connected to the hydraulic circuit Y via the connection circuit Z so as to return to the hydraulic circuit W via the connection circuit Z and flow to the tank T after actuating BC.

  The switching valve 5 is configured as a hydraulic pilot operated three-way valve that operates with a pilot pressure guided by a hydraulic pilot circuit.

That is, when the pilot pressure to the hydraulic unit 5-a1 of the left end side is applied, the spool is moved to the right, as shown in the circuit diagram of FIG. 7, the pressure oil flowing through the hydraulic circuit W is, the lift cylinder LC When flowing in and returning to the return side circuit w2 by performing the operation of “cylinder extension”, it flows into the bucket cylinder BC from the connection circuit z1 via the feed side circuit y1 of the hydraulic circuit Y, and its piston rod After the operation of “cylinder extension” is performed, the flow returns from the return side circuit y2 to the return side circuit w2 of the hydraulic circuit W via the connection circuit z2, and the tank T is operated.

Further, when the pilot pressure to the hydraulic unit 5-b1 at the right side is applied, the spool is moved to the left, as shown in the circuit diagram of FIG. 8, the circuit w2 return side of the hydraulic circuit W, in FIG. As indicated by the arrow, when the pressure oil flowing into the lift cylinder LC causes the piston rod to perform “cylinder contraction” and returns to the tank T by the circuit w1 on the feed side, the connection circuit z3 It flows into the bucket cylinder BC via the circuit y2 on the return side of the hydraulic circuit Y, and after causing the bucket cylinder BC to perform “cylinder contraction”, it flows to the connection circuit z4 by the circuit y1 on the feed side. Then, the flow returns to the circuit w1 on the feed side of the hydraulic circuit W, and the circuit w1 is made to flow so as to return to the tank T.

  In addition, when no pilot pressure is applied to either the left end side operation unit 5-a1 or the right end side operation unit 5-b1, as shown in the circuit diagram of FIG. Is held in a neutral position without any control.

  Accordingly, the hydraulic pilot circuit p5 and p6 for guiding the pilot pressure oil to the switching valve 5 configured as a three-way valve for hydraulic pilot operation is a hydraulic pilot circuit p1 for controlling the operation of the main pilot valve A for hydraulic pilot operation. -Connected to p2.

  The hydraulic pilot circuit p5 connected to the left end side actuating portion 5-a1 of the switching valve 5 is connected to the hydraulic pilot circuit p1 connected to the left end side actuating portion a1 of the main operation valve A, and the right end of the switching valve 5 is connected. The hydraulic pilot circuit p6 connected to the side actuating portion 5-b1 is connected to the hydraulic pilot circuit p2 connected to the actuating portion b1 on the right end side of the main operation valve A. When the pilot pressure oil is supplied to the circuit p1, the pilot pressure is applied to the left end side operation portion a1 of the main operation valve A, and the main operation valve A is moved to the right, the operation portion 5 on the left end side of the switching valve 5 is simultaneously turned on. The pilot pressure is also applied to -a1, so that the switching valve 5 is simultaneously moved to the right, and pressure oil is supplied from the hydraulic source o2 to the hydraulic pilot circuit p2, so that the right end of the main operation valve A On the side actuating part b1 When pressure is applied and the main control valve A is moved to the left, pilot pressure is simultaneously applied to the actuating portion 5-b1 on the right end side of the switching valve 5, so that the switching valve 5 is interlocked to the left. It is designed to move.

  As a result, the operation of moving the main operation valve A to the right is performed, and the pressure oil flowing through the hydraulic circuit W flows into the lift cylinder LC from the circuit w1 on the feed side, thereby operating the “cylinder extension”. When the state is switched to the state in which the pilot valve is operated, the pilot pressure is simultaneously applied to the hydraulic pilot circuit of the switching valve 5, so that the switching valve 5 operates to move to the right in conjunction with the main operation valve A. Is connected to the hydraulic circuit Y via the connection circuits z1 and z2, and the pressure oil flowing through the hydraulic circuit Y flows into the bucket cylinder BC from the circuit y1 on the feed side and causes the operation of “cylinder extension” to be performed. The circuit y2 returns to the circuit w2 on the return side of the hydraulic circuit W and flows into the tank T.

  Further, the operation of moving the main operation valve A to the left is performed, and the pressure oil flowing through the hydraulic circuit W flows into the lift cylinder LC from the return side circuit w2 to perform the “cylinder contraction” operation. When switching to the state, the switching valve 5 moves to the left in conjunction with the main operation valve A by the pilot pressure applied to the pilot circuit of the switching valve 5 at the same time, and the hydraulic circuit W passes through the connection circuits z3 and z4. The hydraulic oil connected to the hydraulic circuit Y flows into the bucket cylinder BC from the return side circuit y2 to perform the “cylinder contraction” operation, and the connection circuit z4 is connected to the feed side circuit y1. After that, the flow returns to the circuit w1 on the feed side of the hydraulic circuit W, and the circuit w1 causes the tank T to flow.

  6 is an on / off control of the connection circuits z1 and z2 in the connection circuit Z when the hydraulic circuit W is connected to the hydraulic circuit Y via the connection circuit Z by the operation of the switching valve 5. A control valve 7 is a control valve for controlling on / off of the connection circuits z3 and z4.

  These control valves 6 and 7 are both configured as hydraulic pilot-operated two-way valves, and are normally maintained in an off position where the connection circuit Z is shut off by a spring load provided on one end side. The connection circuit z1 and z2 of the connection circuit Z are configured to perform an operation of switching to an ON position where the connection circuit Z is communicated by applying a pilot pressure to the operation unit provided on the other end side. Are connected to the connection circuits z3 and z4, respectively.

  The control valves 6 and 7 including these hydraulic pilot-operated three-way valves are configured so that the pilot pressure is applied to their operating parts separately.

The hydraulic pilot circuit p7 that communicates with the actuating part 6-a1 of the control valve 6 includes a hydraulic pilot circuit p5 that communicates with the actuating part 5-a1 on the left end side of the switching valve 5 and the actuating part on the left end side of the main operation valve A. The pilot valve p1 is connected to the hydraulic pilot circuit p1 communicating with a1, and the pilot pressure is introduced from the hydraulic pressure source o1 to the hydraulic pilot circuit p1 of the main operation valve A to move the main operation valve A to the right, and at the same time the switching valve 5 When the control valve 6 is operated to move to the right, the control valve 6 is simultaneously operated by the pilot pressure to bring the connection circuits z1 and z2 into the normal state.

Further, the hydraulic pilot circuit p8 communicating with the operating portion 7-b1 of the control valve 7 is operated on the right end side of the hydraulic pilot circuit p6 communicating with the operating portion 5-b1 on the right end side of the switching valve 5 and the main operation valve A. This is connected to a hydraulic pilot circuit p2 that communicates with the part b1, thereby introducing a pilot pressure from the hydraulic pressure source o2 into the hydraulic pilot circuit p2 of the main operation valve A, and moving the main operation valve A to the left. When the switching valve 5 is moved to the left at the same time, a pilot pressure is applied to the operating portion 7-b1 of the control valve 7, so that the control valve 7 operates in conjunction with the connection. The circuits z3 and z4 are in a communication state.

  As a result, the control valve 6 provided in the connection circuits z1 and z2 and the control valve 7 provided in the connection circuits z3 and z4 simultaneously actuate the switching valve 5 by the operation of the main operation valve A and flow to the hydraulic circuit W. After the pressure oil flows into the lift cylinder LC and performs the operation of “cylinder extension”, it flows into the hydraulic circuit Y through the connection circuit z1 of the connection circuit Z, and gives the operation of “cylinder extension” to the bucket cylinder BC. Then, when the connection circuit z2 returns to the hydraulic circuit W and the state flows into the tank T, only the control valve 6 provided in the connection circuits z1 and z2 is turned on, and the control valve 7 provided in the connection circuits z3 and z4. Will be held off. Further, after the pressure oil flowing in the hydraulic circuit W flows into the lift cylinder LC from the piston rod side and performs the operation of “cylinder contraction”, it flows into the hydraulic circuit Y through the connection circuit z3, When the operation of “cylinder contraction” is applied to the bucket cylinder BC and the state is returned to the hydraulic circuit W by the connection circuit z4 and flows into the tank T, only the control valve 7 provided in the connection circuit z3 · z4 is turned on. The control valve 6 provided in the connection circuits z1 and z2 is held off.

  As described above, the switching valve 5 provided in the hydraulic circuit W and the control valves 6 and 7 provided in the connection circuits z1 and z2 and the connection circuits z3 and z4 that connect the hydraulic circuit W to the hydraulic circuit Y are provided with the lift cylinder LC. The pressure oil flowing to the hydraulic circuit W so as to operate flows into the bucket cylinder BC connected to the hydraulic circuit Y after passing through the lift cylinder LC when the lift cylinder LC is operated to return to the tank T as return oil. Switching the flow path when the lift cylinder LC and the bucket cylinder BC are operated together by switching the flow of pressure oil so as to return to the hydraulic circuit W and flow to the tank T after passing through the bucket cylinder BC. Is to control.

  The operation of the switching valve 5 and the control valves 6 and 7 is performed in conjunction with the operation of the main operation valve A when the lift cylinder LC is operated by the operation of the main operation valve A. This is because the bucket cylinder BC operates in conjunction with the bucket cylinder BC. Further, these valves are configured as hydraulic pilot operated valves, and these hydraulic pilot circuits are connected to constitute the interlocking means, and may be electrical or mechanical interlocking means. Is.

SV shuts off the above-mentioned interlocking means, and prevents the operation of the main operation valve A from being performed when the main operation valve A is operated to operate the flow path switching operation. In this example, the hydraulic pilot circuits p1 and p2 for controlling the operation of the main operation valve A and the hydraulic pilot circuit p5 for controlling the operation of the switching valve 5 are provided. The solenoid valve is provided so as to control connection and disconnection with the hydraulic pilot circuits p7 and p8 that control the operation of p6 and the control valves 6 and 7.

The solenoid valve SV is a normal solenoid-operated pilot valve that controls the opening and closing of the flow path by on / off control of energization to the solenoid provided in the operating portion. In this example, the operation of the main operation valve A is performed. The hydraulic pilot circuit p1 that communicates with the part a1 and the hydraulic pilot circuit p5 that communicates with the operation part 5-a1 of the switching valve 5; the hydraulic pilot circuit p2 that communicates with the operation part b1 of the main operation valve A; The hydraulic pilot circuit p5 that controls the switching valve 5 by disconnecting these flow paths in the flow path that connects the hydraulic pilot circuit p6 that communicates with the operating portion 5-b1. the-p6, by separating from the hydraulic pilot circuit p1, p2 controlling the main operating valve a, together hydraulic pilot circuit p7-p8 for controlling the control valve 6, 7 oil Are so as to be disconnected to the pilot circuit p1 · p2.

  Then, on / off control of energization to the solenoid of the operating portion of the solenoid valve SV is performed on a control panel installed in the cabin b of the vehicle body 1, for example, as shown in FIGS. A switch 9 that is turned on / off when the 90 is raised and lowered is provided, and this is performed by operating the operation rod 90.

  If the switch 9 is turned off by manual operation so that the solenoid valve SV is not energized and the flow path is shut off, the switching valve 5 and the control valves 6 and 7 do not operate, and the hydraulic circuit W is maintained in a normal state, and the connection circuit Z is maintained in a shut-off state. The main operation valves A and B operate independently of each other, and are individually connected to the lift cylinder LC and the bucket cylinder BC. The "cylinder extension" and "cylinder reduction" operations are performed.

Also, the switch 9 is turned on, the solenoid valve SV is turned on by energization, the aforementioned flow path is opened, and the hydraulic pilot circuits p5 and p6 that control the switching valve 5 and the hydraulic pressure that controls the control valves 6 and 7 If the pilot circuits p7 and p8 are connected to the hydraulic pilot circuits p1 and p2 for controlling the main operation valve A, when the main operation valve A is operated, the switching valve 5 and the control valves 6 and 7 are simultaneously When the main operation valve A is moved to the right and the pressure oil flowing in the hydraulic circuit W applies the operation of “cylinder extension” to the lift cylinder LC and returns to the tank T, The pressure oil that has actuated the lift cylinder LC flows to the hydraulic circuit Y through the connection circuits z1 and z2, causes the bucket cylinder BC to perform the “cylinder extension” operation, and returns to the hydraulic circuit W through the connection circuit z2. To flow in T.

  Further, when the main control valve A is moved to the left and the pressure oil flowing through the hydraulic circuit W causes the lift cylinder LC to perform “cylinder contraction”, the pressure oil that operated the lift cylinder LC is It flows to the hydraulic circuit Y by the connection circuit z3, causes the bucket cylinder BC to perform “cylinder contraction”, returns to the hydraulic circuit W through the connection circuit z4, and flows to the tank T.

  That is, the pressure oil that flows into the lift cylinder LC and operates the cylinder and flows out from the cylinder flows into the bucket cylinder BC as it is, operates the cylinder, and returns to the tank T.

  At this time, since the pressure oil that flows into the bucket cylinder BC and operates the cylinder is pressure oil that operates the lift cylinder LC and flows out of the cylinder, the amount of oil is supplied to the lift cylinder LC. It becomes approximately equal to the amount of pressure oil. Since the bucket cylinder BC is formed to have substantially the same volume as the lift cylinder LC, the bucket cylinder BC operates with substantially the same operation amount as the lift cylinder LC.

  Accordingly, when the lift boom 2 is rotated upward by the operation of the lift cylinder LC to lift the bucket 3 and the cargo handling operation is performed, the operation amount of the lift cylinder LC that rotates the lift boom 2 upward, and the bucket 3 is lifted. The operation amount of the bucket cylinder BC that rotates in the direction opposite to the rotation direction of the lift boom 2 is equal to the boom 2, and the bucket 3 is opposite in the direction corresponding to the rotation angle of the lift boom 2. By tilting and rotating, the ground posture is maintained substantially horizontal.

  FIG. 11 shows another embodiment. In this embodiment, the switching valve 5 provided in the hydraulic circuit W of the lift cylinder LC and the control valves 6 and 7 provided in the connection circuit Z connecting the hydraulic circuit Y of the bucket cylinder BC to the hydraulic circuit W are provided with the main operation valve A. The switching valve 5 and the control valves 6 and 7 are respectively configured as electromagnetic valves to be operated in conjunction with the operation / operation of the above, and this operation is controlled by on / off control of energization to the electric circuit. This is an example in which the operation of the main operation valve A is interlocked. Therefore, there are no hydraulic pilot circuits p5, p6, p7, and p8 that guide the hydraulic pilot pressure to the switching valve 5 and the control valves 6 and 7, and the main operation valve A and the main operation valve B that are configured to operate with the pilot pressure. It is assumed that only the hydraulic pilot circuits p1, p2, p3, and p4 for operating are left.

  Further, in order to turn on / off the connection of the hydraulic pilot circuits p1 and p2 of the main operation valve A to the hydraulic pilot circuits p5, p6, p7 and p8, it is provided as shown in the circuit diagram of FIG. The solenoid valve SV is omitted because it is unnecessary.

  The switching valve 5 is divided into two, and each is formed as a two-way solenoid valve. The first switching valve 5-1 is provided on the feed side w1 of the hydraulic circuit W, and the second switching valve 5 The valve 5-2 is provided on the return side w2 of the hydraulic circuit W. The first and second switching valves 5-1 and 5-2 and the control valves 6 and 7 are normally held at the closed position of the hydraulic circuit, and are operated to open the hydraulic circuit when energized. Yes, when the first switching valve 5-1 is opened to the "cylinder extension" state, the control valve 7 is opened in conjunction with the pressure oil passing through the bucket cylinder BC in the "cylinder extension" state, and the added return When the second switching valve 5-2 is opened and the cylinder is contracted, the control valve 6 is opened and the lift cylinder LC is operated to “cylinder contraction”. The pressurized oil is returned to the tank T by the return circuit N through the bucket cylinder BC.

  In this embodiment, the first and second switching valves 5-1 and 5-2 and the control valves 6 and 7, which are configured as electromagnetic valves, are controlled so as to keep energization to the respective electric circuits off. The main operation valve A and the main operation valve B operate independently, and therefore, the lift cylinder LC and the bucket cylinder BC operate independently. Further, the electric circuit of each of the first and second switching valves 5-1 and 5-2 and the control valves 6 and 7 is moved to the position of “cylinder extension” when the main operation valve A is operated / operated. The first switching valve 5-1 and the control valve 7 operate in conjunction with each other to open the hydraulic circuit, and when the main operation valve A is operated to the “cylinder contraction” position, If the 2 switching valve 5-2 and the control valve 6 operate in conjunction with each other so that the hydraulic circuit is opened, the lift cylinder LC is operated by operating the main operation valve A. The pressure oil flowing through the lift cylinder LC and passing through the cylinder LC flows directly into the bucket cylinder BC and returns to the tank T. The same amount of pressure oil flows into the bucket cylinder BC, and the same operating amount as the lift cylinder LC. Then, the bucket cylinder BC is operated.

  FIG. 12 shows still another embodiment. In this example, the switching valve 5 is divided into a first switching valve 5-1 and a second switching valve 5-2, which are respectively connected to the feed side w1 and the return side w2 of the hydraulic circuit W of the lift cylinder LC. Although the control valves 6 and 7 are connected to the connection circuits z1 and z2 and the connection circuits z3 and z4, respectively, they are the same as those in the embodiment shown in FIG. This is an example in which the second switching valves 5-1 and 5-2 and the control valves 6 and 7 are configured as hydraulic pilot operated valves that operate with hydraulic pilot pressure. The operation of these valves is performed in conjunction with the operation of the main operation valve A. The hydraulic pilot circuits p5, p6, p7, and p8 of those valves are used as the hydraulic pilot circuit p1 of the main operation valve A. -This is an example of interlocking with hydraulic pilot pressure by connecting with p2.

  In order to turn on / off this interlocking / operation, the solenoid valve SV provided between the hydraulic pilot circuits p5, p6, p7, and p8 of these valves and the hydraulic pilot circuits p1 and p2 of the main operation valve A is: The first solenoid valve SV-1 and the second solenoid valve SV-2 are divided into the first solenoid valve SV-1 and the hydraulic pilot circuit p1 of the main operation valve A and the second switching valve 5-2. The hydraulic pilot circuit p6 and the control valve 7 are connected to the hydraulic pilot circuit p1 so as to be turned on / off, and the second solenoid valve SV-2 is connected to the main operation valve A. The hydraulic pilot circuit p2 is connected to the hydraulic pilot circuit p2 so as to turn on / off the connection between the hydraulic pilot circuit p5 of the first switching valve 5-1 and the hydraulic pilot circuit p7 of the control valve 6. Further, the first and second switching valves 5-1 and 5-2 and the control valves 6 and 7 are normally held at the positions shown in FIG. 12 and connected to the hydraulic circuit.

  In this embodiment, if the first and second solenoid valves SV-1 and SV-2 are not energized, the first and second switching valves 5-1 and 5-2 and the control valve will be described. Since 6 and 7 are in the state positions shown in FIG. 12, the main operation valve A and the main operation valve B are operated independently, and the lift cylinder LC and the bucket cylinder BC are operated separately.

  Further, if the first and second solenoid valves SV-1 and SV-2 are energized in conjunction with the operation of the main operation valve A, the main operation valve A is set to “cylinder extension”. When operated to the position (right position), the first solenoid valve SV-1 operates in conjunction with the energization on so that the second switching valve 5-2 and the control valve 7 are operated by the hydraulic pilot pressure. The pressure oil flows through the lift cylinder LC so that the piston pushes the piston into the bucket cylinder BC, and then returns to the tank T through the return circuit N. When the same amount of work is performed with oil and the main operation valve A is operated to the “cylinder contraction” position (leftward position), energization to the second solenoid valve SV-2 is performed in conjunction. As a result, the first switching valve 5-1 and the control valve 6 are moved by the pressure oil pilot pressure. The pressure oil that has flown in the direction of “cylinder contraction” in the lift cylinder LC flows to the bucket cylinder BC, flows in the direction of “cylinder contraction”, and passes through the return circuit N to the tank. Returning to T, the bucket cylinder BC is operated with the same operation amount as the lift cylinder LC.

  FIG. 13 shows a further different embodiment. In this example, the hydraulic circuit W of the lift cylinder LC, which is controlled to perform the operation of “cylinder expansion” and “cylinder contraction” on the lift cylinder LC by the operation of the main operation valve A, the main operation The hydraulic circuit Y of the bucket cylinder BC, which is controlled to perform the operations of “cylinder expansion” and “cylinder contraction” on the bucket cylinder BC by the operation of the valve B, and the pressure oil that has flowed to the hydraulic circuit W of the lift cylinder LC However, after passing through the lift cylinder LC, it flows into the hydraulic circuit Y of the bucket cylinder BC and is connected by the connection circuit Z so as to return to the tank T after passing through the bucket cylinder BC. The main control valve A gives the lift cylinder LC each operation of “cylinder expansion” or “cylinder contraction” in the state of connection communication between the hydraulic circuit Y and the hydraulic circuit Y. Is switched to the bucket cylinder BC so that the corresponding operation of “cylinder expansion” or “cylinder contraction” is applied to the connection portion of the connection circuit Z to the hydraulic circuit W and the hydraulic circuit Y. The switching control valve v1 and the switching control valve v2 that are provided are operated in conjunction with each other, and the switching control valve v1 and the switching control valve v2 are configured as valves that are operated by hydraulic pilot pressure, and they are operated. The hydraulic pilot circuit to be operated is connected to the hydraulic pilot circuit p1 and the hydraulic pilot circuit p2 of the main operation valve A as shown by the broken line in FIG. Eliminates the stagnation of pressure oil generated in the hydraulic pilot circuit when the pilot pressure is operated in conjunction with the operation of the main control valve A It is an example Unishi to have.

  Pressure control circuits controlled so as to switch to and communicate with the hydraulic power source O and the tank T by the solenoid valve SV3, respectively, in the hydraulic pilot circuits of the switching control valve v1 and the switching control valve v2 that are operated by the hydraulic pilot pressure. M are connected to each other so as to cope with the stagnation of the pressure oil generated in the hydraulic pilot circuit.

It is a side view of a large-sized bucket loader type construction machine vehicle. It is a side view of a small bucket loader type construction machine vehicle. It is a top view of a construction machine vehicle same as the above. It is explanatory drawing for demonstrating the principle of this invention means. It is a circuit diagram which shows the circuit structure of the hydraulic pressure which operates the lift cylinder and bucket cylinder of a conventional means. It is a circuit diagram of the hydraulic circuit which operates the lift cylinder and bucket cylinder of the Example apparatus of this invention. FIG. 3 is a circuit diagram of a hydraulic circuit when the lift cylinder is set to “cylinder extension” in the apparatus. FIG. 3 is a circuit diagram of a hydraulic circuit when the lift cylinder is in a “cylinder contraction” state in the apparatus. It is a side view of the switch which controls the solenoid valve of an apparatus same as the above. It is a top view of a switch same as the above. It is a circuit diagram which shows the circuit structure of the hydraulic pressure of another Example. It is a circuit diagram which shows the circuit structure of the hydraulic pressure of another Example. Furthermore, it is a circuit diagram which shows the circuit structure of the hydraulic pressure of another Example.

Explanation of symbols

A, B Main control valve BC, BC1, BC2 Bucket cylinder F1, F2 Main hydraulic source GL Ground surface LC, LC1, LC2 Lift cylinder M Pressure adjustment circuit N Return circuit O Hydraulic source S Support shaft SV Solenoid valve SV-1 First electromagnetic Valve SV-2 Second solenoid valve SV3 Solenoid valve T Tank V Interlocked valve group linked to the main operation valve W Hydraulic circuit Y Hydraulic circuit Z Connection circuit a Power source a1 Actuator on the left end side of the main operation valve A b Driver's seat ( cabin)
b1 Actuating portion on the right end side of the main control valve B c Turning mechanism d Turning frame e Mounting bracket o1, o2, o3, o4 Hydraulic source p1, p2, p3, p4, p5, p6, p7, p8 Hydraulic pilot circuit v1, v2 Switching control valve w1 Feeding side circuit w2 Returning side circuit y1 Feeding side circuit y2 Returning side circuit z1, z2, z3, z4 Connection circuit 1 Car body 10 Traveling device 2 Lift boom 3 Handling bucket 30 Bucket pin 4 Link mechanism 41 Bucket link center pin 42 Bucket link 43 Connecting rod 5 Switching valve 5-1 First switching valve 5-2 Second switching valve 5-a1 Left end side operating part 5-b1 Right end side operating part 6-7 Control valve 6 -A1 ・ 7-b1 Control valve actuator 9 Switch 90

Claims (4)

The lift cylinder (LC) for rotating the lift boom (2) and the bucket cylinder (BC) for rotating the cargo handling bucket (3) are configured to have substantially the same volume .
Hydraulic circuit ( W ) of lift cylinder (LC) that rotates lift boom (2)
When,
A main operation valve (A) for controlling the flow of pressure oil in the hydraulic circuit (W);
A hydraulic circuit ( Y ) of a bucket cylinder (BC) for rotating the cargo handling bucket (3) ;
A main operation valve (B) for controlling the flow of pressure oil in the hydraulic circuit (Y);
By connecting the hydraulic circuit (W) and the hydraulic circuit (Y), the return oil of the pressure oil supplied to the lift cylinder (LC) is supplied to the bucket cylinder (BC) and the bucket cylinder ( A connection circuit (Z) for returning to the tank (T) via BC) ;
A switching valve (5), a control valve (6) and a control valve (7) for controlling the flow of pressure oil in the connection circuit (Z);
By operating the main operation valve (A), the switching valve (5), the control valve (6) and the control valve (7), the connection circuit (Z) is connected to the hydraulic circuit (W) and the hydraulic circuit ( Y) and interlocking means for interlocking the operation of the bucket cylinder (BC) with the operation of the lift cylinder (LC);
A disconnecting means for controlling connection / disconnection of the interlocking means,
The interlocking unit operates the main operation valve (A), the switching valve (5), the control valve (6), and the control valve (7), and the connection circuit (Z) is connected to the hydraulic circuit (W). wherein when to connect the hydraulic circuit (Y), when the lift boom (2) is raised rotated by the operation of the lift cylinder (LC), said bucket cylinder (BC) is the lift cylinder ( in conjunction with the operation of the LC), in approximately equal actuation amount the operation amount of the lift cylinder (LC), is pivoted the cargo handling bucket (3) in the rotational direction opposite to the direction of the lift boom (2) ,
When the shut-off means shuts off the interlocking by the interlocking means, the lift boom (2) and the bucket cylinder (BC) can be independently operated. Automatic tilt angle control device. In the automatic control device of the inclination angle of the cargo handling work machine in the construction machine vehicle according to claim 1,
The main operation valve (A) has a flow path state in which the pressure oil flowing in the hydraulic circuit (W) flows in a direction in which the lift cylinder (LC) is operated to “cylinder extension”, and the pressure oil is “cylinder contraction”. The flow path state of the pressure oil can be switched to one of three states, a flow path state that flows in the direction of operation and a "neutral" flow path state that blocks the flow of pressure oil ,
The main operation valve (B) has a flow path state in which the pressure oil flowing in the hydraulic circuit (Y) flows in a direction in which the bucket cylinder (BC) is operated to “cylinder expansion”, and the pressure oil is “cylinder contraction”. The flow path state of pressure oil can be switched to one of three states, a flow path state that flows in the direction of operation and a flow path state that blocks the flow of pressure oil ,
In the state where the hydraulic circuit (W) is switched to the “cylinder extension” flow path state, the connection circuit (Z) is configured so that the circuit on the return side of the hydraulic circuit (W) is the hydraulic circuit (Y). And a connection circuit (z2) for connecting a return circuit of the hydraulic circuit (Y) to a return circuit of the hydraulic circuit (W). When the hydraulic circuit (W) is switched to the “cylinder contraction” flow path state, the return side circuit of the hydraulic circuit (W) is connected to the feed side circuit of the hydraulic circuit (Y). A connection circuit (z3) that connects the return circuit of the hydraulic circuit (Y) to a return circuit of the hydraulic circuit (W) , and
The switching valve (5) is interlocked with the operation of the main operation valve (A) by the interlocking means, and the hydraulic circuit (W) is moved to the lift cylinder (LC) when in the “cylinder extension” flow path state. The return oil of the pressure oil having passed through the flow flows to the hydraulic circuit (Y) via the connection circuit (z1), and further from the bucket cylinder (BC) to the hydraulic circuit via the connection circuit (z2). In the flow state returning to the tank (T) of (W) and the flow path state of “cylinder contraction”, the return oil of the pressure oil that has passed through the lift cylinder (LC) passes through the connection circuit (z3). A flow state that flows into the hydraulic circuit (Y) and returns from the bucket cylinder (BC) to the tank (T) of the hydraulic circuit (W) via the connection circuit (z4); Circuits (z1) and (z2) and the connection circuit (z3) Without going through (z4) back to the tank (T) of the hydraulic circuit (W) can be switched between a state of "neutral", characterized in that the loading machine in construction equipment vehicles according to claim 1 Automatic control device for tilt angle. In the automatic control device of the inclination angle of the cargo handling work machine in the construction machine vehicle according to claim 2,
The main operation valve (A) is operated by pilot pressure oil flowing through the hydraulic pilot circuits (p1) and (p2) ,
The switching valve (5) is operated by pilot pressure oil flowing through the hydraulic pilot circuits (p5) and (p6) ,
The control valve (6) and the control valve (7) are actuated by pilot pressure oil flowing through the hydraulic pilot circuits (p7) and (p8), respectively .
By connecting the hydraulic pilot circuits of the switching valve (5), control valve (6) and control valve (7) to the pilot circuit of the main operation valve (A), the switching valve (5), control The operation of the valve (6) and the control valve (7) can be linked to the operation of the main operation valve (A) , and
By shutting off the linkage between the pilot circuit of the main operation valve (A) and the hydraulic pilot circuit of the switching valve (5), the control valve (6) and the control valve (7) by the shut-off means, The automatic control device for the inclination angle of the load handling machine in the construction machine vehicle according to claim 2, wherein the lift cylinder (LC) and the bucket cylinder (BC) can be operated independently. In the automatic control device of the tilt angle of the cargo handling work machine in the construction machine vehicle according to claim 3,
  The inclination angle of the cargo handling work machine in the construction machine vehicle according to claim 3, wherein the shut-off means shuts off the interlock by manual operation so that the main operation valve (A) can operate independently. Automatic control device.

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