JP2012215274A - Working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working machine in which flexibility of actuation combination setting is increased.SOLUTION: A skid-steer loader includes a hydraulic actuator, a control means, and a pilot pressure generation means generating a pilot pressure. The pilot pressure generation means includes: right and left levers 30, 40 capable of performing tilting operations in a plurality of directions; and a plurality of pilot valves 31 to 34, 41 to 44 generating the plurality of pilot pressures corresponding to the tilting operations of the operation levers. A pilot hydraulic passage includes a combination switching valve 50 in which a first switching hydraulic passage connecting the pilot valves, a servo piston, and a control valve with a first connection pattern and the second switching hydraulic passage for performing the connection with a second connection pattern are formed. The pilot pressure generation means is also configured to be capable of generating the plurality of pilot pressures by the simultaneous actuation of the plurality of pilot valves in response to the tilting directions in the tilting operations of the operation levers.

Description

  The present invention relates to a work machine that performs work by operating a work device using a hydraulic actuator.

  As an example of the working machine as described above, a skid steer loader, a power shovel, and the like that are used when excavating the ground or moving the excavated earth and sand are widely known. Of these, the skid steer loader has, for example, an arm that is swingable up and down with respect to a vehicle body that is configured to be able to run, and a bucket that scoops earth and sand is attached to the tip of the arm so as to swing up and down. Configured. In addition, a pair of left and right operating levers are provided in the operator cabin provided on the vehicle body, and the hydraulic actuator is operated according to the tilting direction and the tilting amount by tilting these operating levers back and forth and left and right. Thus, the vehicle body can be moved back and forth, and the arms and buckets can be swung up and down. Specifically, a pilot valve (also referred to as a remote control valve) that generates pilot pressure in response to the tilting operation of the operation lever is provided at the base of the operation lever, and connects the pilot valve and the control valve. The pilot pressure is input to the control valve via the pilot oil passage, and the arm or the like is operated.

  By the way, the combination of the tilting operation with respect to the operation lever in the skid steer loader and the hydraulic actuator operated in accordance with the tilting operation (hereinafter simply referred to as “operation combination”) may differ depending on the manufacturer, for example. , Not completely unified. Therefore, when the operator tries to operate the skid steer loader with his / her familiar operation combination, for example, it is necessary to temporarily remove the pilot valve and change the mounting position, or to change the oil path from the pilot valve to the control valve. . In such operations, there is a risk that dust may enter the oil passage or hydraulic oil may leak out when the oil passage is changed. Therefore, in Patent Document 1, by providing a pattern switching valve in the oil passage from the pilot valve (piston) to the control valve, dust is not mixed into the oil passage or hydraulic oil leaks out, and two different ones can be obtained. A hydraulic circuit configured to be able to switch operation combinations is disclosed.

Japanese Patent No. 3880754

  However, in the configuration disclosed in Patent Document 1, when the operation lever is tilted back and forth and left and right, a single pilot pressure is generated from one pilot valve, and this single pilot pressure is used as the pilot oil passage. Therefore, there is a problem that the degree of freedom in setting the operation combination tends to be low.

  This invention is made | formed in view of the above subjects, and it aims at providing the working machine which raised the freedom degree of the setting of an action | operation combination.

  In order to achieve the above object, a work machine according to the present invention (for example, the skid steer loader 1 in the embodiment) includes a plurality of devices for operating the work device (for example, the crawler mechanism 16, the arm 21, and the bucket 22 in the embodiment). Hydraulic actuators (for example, the right traveling hydraulic motor 26R, the left traveling hydraulic motor 27L, the arm cylinder 28, and the bucket cylinder 29 in the embodiment) and the plurality of hydraulic actuators are provided, and pressure oil to the hydraulic actuators is provided. A plurality of control means for controlling supply (for example, the right servo piston 26c, the left servo piston 27c, the arm cylinder control valve 28c, and the bucket cylinder control valve 29c in the embodiment) and the operation of the control means Multiple A working machine having a pilot pressure generating means for generating a lot pressure, wherein the pilot pressure generating means is an operation lever that can be tilted in a plurality of directions (for example, the left operation lever 30 and the right operation lever 40 in the embodiment). ) And a plurality of pilot valves that generate a plurality of pilot pressures corresponding to the tilting operation of the operation lever (for example, the first to fourth pilot valves 31 to 34 and the first to fourth pilot valves 41 to 44 in the embodiment). ), And a plurality of pilot pressures generated by the pilot valve are connected to the pilot valve and the control means (for example, first to fourth input lines 31a in the embodiment). 34a, fifth input line 42a, sixth input line 44a, first to sixth output lines 61a-66. ) To the control means, the operation of the control means is controlled, and in advance according to the connection pattern between the plurality of pilot valves and the plurality of control means by the plurality of pilot oil passages. A combination of a tilting operation with respect to the operation lever in a predetermined direction set and the control means that is operated in accordance with the tilting operation in the predetermined direction is set, and the pilot valve and the control means are provided in the pilot oil passage. A first switching oil passage (for example, an oil passage communicated at the first rotational position in the embodiment) and a second connection pattern different from the first connection pattern. A second switching oil passage (for example, the second circuit in the embodiment) that connects the pilot valve and the control means. Connecting pattern switching means (for example, the combination switching valve 50 in the embodiment) formed with an oil passage communicated at a rotation position, the pilot pressure generating means according to the tilting direction in the tilting operation of the operation lever. The plurality of pilot valves can be operated simultaneously to generate a plurality of pilot pressures.

  In the work machine described above, it is preferable that the pilot valves are respectively disposed at positions symmetrical with respect to a reference line extending in the predetermined direction through the tilting center of the operation lever.

  In the work machine described above, one of the first switching oil passage and the second switching oil passage selectively transmits a high-pressure side pilot pressure among a plurality of pilot pressures. It is preferable to include a shuttle valve (for example, the first to fourth shuttle valves 71 to 74 in the embodiment).

  The work machine described above includes two pilot pressure generating means, and each of the pilot pressure generating means includes the operation lever and the plurality of pilot valves, and the pilot pressure generating means includes the pilot pressure generating means. A plurality of pilot valves and the plurality of control means are connected by the plurality of pilot oil passages, and each of the single pilot pressures generated by the plurality of pilot valves in each of the pilot pressure generating means, It is configured to be transmitted to the plurality of control means via a plurality of pilot oil passages, and the connection pattern switching means switches the plurality of pilot oil passages to switch the first connection pattern and the second It is preferable to switch between connection patterns.

  In the work machine described above, when the operation lever in each of the pilot pressure generation means is tilted in the same direction in the predetermined direction, one of the pilot pressure generation means is single in the plurality of pilot valves. It is preferable that the other pilot pressure generating means simultaneously generates a plurality of pilot pressures in the plurality of pilot valves.

  Further, the working device includes: a traveling device that travels a vehicle body; an arm that is swingable up and down with respect to the vehicle body; and a bucket that is swingable up and down at a tip portion of the arm. It is preferable that the hydraulic actuator includes a traveling hydraulic motor that operates the traveling device, an arm cylinder that swings the arm, and a bucket cylinder that swings the bucket.

  The work machine of the present invention is configured such that a plurality of pilot valves can be simultaneously operated to generate a plurality of pilot pressures in accordance with the tilting direction in the tilting operation of the operation lever. For this reason, for example, depending on the tilting direction of the operation lever, a combination of a setting for generating one pilot pressure and a setting for generating two pilot pressures enables various operation combinations to be set. Can increase the degree of freedom. Furthermore, by providing the connection pattern switching means in this configuration, it is possible to switch between the two operation combinations, and it is possible to configure a highly convenient work machine.

  In the work machine described above, it is preferable that the pilot valves are arranged at positions symmetrical with respect to a reference line extending in a predetermined direction through the tilting center of the operation lever. When configured in this way, when the operation lever is tilted in a predetermined direction (for example, front, back, left, and right), it is possible to reliably generate a pilot pressure with a plurality of pilot valves arranged at symmetrical positions.

  Further, in the above-described work machine, one of the first switching oil passage and the second switching oil passage selectively transmits a high-pressure side pilot pressure among a plurality of pilot pressures. It is preferable to provide. By configuring in this way, for example, a connection pattern switching means can be configured by inserting an oil passage switching portion in a valve body portion so as to be slidable and rotatable. Further, the oil passage switching portion is provided with respect to the valve body portion. By rotating, the first connection pattern and the second connection pattern can be easily switched.

In the above-described work machine, a configuration in which two pilot pressure generating units are provided, and each of the pilot pressure generating units includes an operation lever and a plurality of pilot valves is preferable.
In the case of this configuration, for example, compared to a configuration including one pilot pressure generating means, the degree of freedom in setting the operation combination is further increased, and various operation combinations can be set.

  In the above-described work machine, when the operating lever is operated in the same direction, one pilot pressure generating means generates a single pilot pressure and the other pilot pressure generating means simultaneously generates a plurality of pilot pressures. The structure to be made is preferable. When configured in this way, the control means can output each of a plurality of pilot pressures generated by one and the other pilot pressure generating means, thereby further increasing the degree of freedom in setting the operation combination.

  Furthermore, it is preferable that the working device includes a traveling device, an arm, and a bucket, and the hydraulic actuator includes a traveling hydraulic motor, an arm cylinder, and a bucket cylinder. By providing such a working device and a hydraulic actuator, for example, a skid steer loader can be configured, and even when the vehicle body is greatly shaken, a skid steer that can stably hold the tilting position of the operation lever. A loader can be provided.

It is a figure which shows the skid steer loader as an example of the working machine to which this invention is applied, Comprising: (a) is the top view, (b) is the side view. It is a front view of the said skid steer loader. (A) is the figure which showed the relationship between the tilt direction when set to the 1st action | operation combination, and the action | operation content, (b) shows the hydraulic circuit when set to the 1st action | operation combination. (A) is the figure which showed the relationship between the tilting direction when set to the 2nd action | operation combination, and the action | operation content, (b) shows the hydraulic circuit when set to the 2nd action | operation combination. It is an enlarged view of the hydraulic circuit formed in the combination switching valve. (A) And (b) is the figure which showed the cross section of the combination switching valve typically.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. A skid steer loader 1 as an example of a work machine to which the present invention is applied is shown in FIGS. 1 and 2. First, a schematic configuration of the skid steer loader 1 will be described with reference to these drawings. In the following description, for convenience of description, description will be made using front and rear, left and right, and up and down directions added to FIGS.

  The skid steer loader 1 includes a vehicle body 10 configured to be able to travel and a loader device 20 provided on the vehicle body 10. A bucket 22 and a pile driving device (see FIG. An attachment such as (not shown) is detachably attached. In the present embodiment, a configuration example in which a bucket 22 for scooping earth and sand is attached to the tip of the arm 21 is shown.

  The vehicle body 10 includes a vehicle body frame 11 that forms a housing of the skid steer loader 1, an operator cabin 12 provided at the upper portion of the vehicle body frame 11, and a traveling device 15 that includes a pair of crawler mechanisms provided on the left and right sides of the vehicle body frame 11. And is configured.

  The vehicle body frame 11 includes left and right side frames 11a that protrude upward at the rear of the vehicle body, and a base frame 11b that connects the side frames 11a to each other at the bottom of the vehicle body. A rear cover 11c that can be opened and closed rearward is provided at the rear of the vehicle body. An engine that is a power source, a hydraulic pump that is driven by the engine, and the like are surrounded by the vehicle body frame 11 and the rear cover 11c. Is arranged.

  The operator cabin 12 is formed in a rectangular box-like frame shape that is located at the center in the front-rear direction of the vehicle body 10 and protrudes upward from the vehicle body frame 11. As shown in FIG. 2, an operator seat 13 is provided inside the operator cabin 12 so that the operator can sit facing the front of the vehicle. In the present embodiment, an operator cabin 12 is illustrated that is protected by a side plate that is open at the front of the vehicle and that has a large number of rectangular holes on the left and right sides.

  The traveling device 15 includes a pair of crawler mechanisms 16 provided on the left and right sides of the vehicle body 10. FIG. 1B shows a crawler mechanism 16 provided on the left side of the vehicle body 10, and this crawler mechanism 16 is provided with a left traveling hydraulic motor 27 </ b> L (in FIG. 3 and FIG. 3) provided inside the vehicle body frame 11. 4)), a idler wheel 16b and a track crawler 16c rotatably supported by the vehicle body frame 11, and a track belt (crawler belt) spanned between the sprocket 16a and the idler wheel 16b. 16d. A similar crawler mechanism 16 is also provided on the right side of the vehicle body 10, and a sprocket 16 a constituting the crawler mechanism 16 on the right side of the vehicle body 10 is provided with a right traveling hydraulic motor 26 R (see FIG. 3 and FIG. 4).

  The loader device 20 is mainly composed of a pair of left and right arms 21 provided on the side frame 11a so as to be swingable up and down, and an arm cylinder 28 that moves the arms 21 up and down. The arm 21 includes a base arm portion 21a whose base end side is pivotally connected to the upper portion of the side frame 11a and extending forward of the vehicle body, and a bent arm portion 21b which is connected to the distal end side of the base arm portion 21a and bends obliquely downward. The tube side end portion of the arm cylinder 28 is pivoted to the side frame 11a, and the rod side end portion is pivoted to the proximal end side of the bending arm portion 21b. For this reason, the arm 21 can be swung up and down (raised) by extending and retracting the arm cylinder 28.

  The front ends of the pair of left and right arms 21, 21 extend forward of the vehicle body frame 11, and a back plate 24 is pivotally connected to the front end portion of the arm 21 via a pivot pin 23 so as to be vertically swingable. A bucket 22 is attached to the back plate 24 via a quick hitch mechanism 25. Thus, by interposing the quick hitch mechanism 25, the operation of attaching / detaching the attachment such as the bucket 22 to the back plate 24 can be easily performed. A bucket cylinder 29 is straddled between the tip of the arm 21 and the back plate 24, and the bucket 22 swings up and down with respect to the arm 21 by operating the bucket cylinder 29 to expand and contract. .

  In the skid steer loader 1, as shown in FIG. 2, a left operation lever 30 is provided on the left side of the operator seat 13, and a right operation lever 40 is provided on the right side. An operator seated on the operator seat 13 tilts the left and right operating levers 30 and 40 forward, backward, left, and right, so that the right traveling hydraulic motor 26R, the left traveling hydraulic motor 27L, the arm cylinder 28, and the bucket cylinder 29 (hereinafter, referred to as the left traveling lever 30). These are collectively referred to as “hydraulic actuators”). Therefore, the left operation lever 30 and the right operation lever 40 are tilted back and forth and left and right to move the vehicle body 10 forward and backward and left and right, and the loader device 20 swings the bucket 22 up and down. By performing it in combination, for example, the work of scooping earth and sand and moving it to another place can be performed.

  So far, the general configuration of the skid steer loader 1 has been described. As shown in FIG. 3 (b), the skid steer loader 1 includes a combination switching valve 50 to form a hydraulic circuit 2. The combination switching valve 50 allows the first operation shown in FIG. 3 (a). The combination and the second operation combination shown in FIG. 4A can be easily switched. Therefore, an operator who operates the skid steer loader 1 can perform an operation by selecting an operation combination that is easier for the user to operate among the first operation combination and the second operation combination. The hydraulic circuit 2 will now be described with additional reference to FIGS. First, components of the hydraulic circuit 2 will be described.

  As shown in FIGS. 3B and 4B, the hydraulic circuit 2 is disposed at the root portion of the left pilot valve unit 39 and the right operation lever 40 disposed at the root portion of the left operation lever 30. The right pilot valve unit 49, the right servo piston 26c that controls the operation of the right hydraulic pump 26p that supplies pressure oil to the right traveling hydraulic motor 26R, and the pressure oil are supplied to the left traveling hydraulic motor 27L. A left servo piston 27c that controls the operation of the left hydraulic pump 27p, an arm cylinder control valve 28c that controls supply / discharge of pressure oil to / from the arm cylinder 28, and a bucket cylinder that performs supply / discharge control of pressure oil to the bucket cylinder 29 Each control valve 29c, left pilot valve unit 39 and right pilot valve unit 49 The piston 26c, 27c and the control valves 28c, constituted by a combination switching valve 50 provided in an oil passage leading to 29c.

  The left pilot valve unit 39 includes four pilot valves (first pilot valve 31 to fourth pilot valve 34), and is based on pressure oil supplied from a pilot pump (not shown) driven by the engine. Thus, the pilot pressure corresponding to the tilt operation direction and the tilt amount with respect to the left operation lever 30 is generated. As shown in FIG. 3A, the four pilot valves 31 to 34 include a first pilot valve 31 on the rear left side, a second pilot valve 32 on the front left side, and a third pilot on the front right side with respect to the left operation lever 30. The valve 33 and the fourth pilot valve 34 are respectively disposed on the right rear side.

  Specifically, when the right side with respect to the left operation lever 30 is set at 0 degree, the third pilot valve 33 is about 45 degrees, the second pilot valve 32 is about 135 degrees, and the first pilot valve 31 is about It is arranged around the left operating lever 30 so that the fourth pilot valve 34 is at a position of about 315 degrees at 225 degrees. Therefore, for example, when the left operating lever 30 is tilted forward, the second pilot valve 32 and the third pilot valve 33 positioned on the front side of the left operating lever 30 are pressed, and in these pilot valves 32 and 33, A pilot pressure is generated.

  The right pilot valve unit 49 includes four pilot valves (first pilot valve 41 to fourth pilot valve 44), and tilts the right operation lever 40 based on pressure oil supplied from the pilot pump. A pilot pressure corresponding to the direction and the amount of tilting is generated. As shown in FIG. 3A, the four pilot valves 41 to 44 include a first pilot valve 41 on the right side, a second pilot valve 42 on the rear side, and a third pilot valve 43 on the left side with respect to the right operation lever 40. A fourth pilot valve 44 is provided on the front side. Therefore, for example, when the right operation lever 40 is tilted forward, the fourth pilot valve located on the front side of the right operation lever 40 is pressed, and pilot pressure is generated in the fourth pilot valve 44.

  The right servo piston 26c includes a forward pilot port 26f and a reverse pilot port 26r, and an internal piston (not shown) corresponding to the pilot pressure acting on the forward pilot port 26f and the reverse pilot port 26r. Has been moved. The right hydraulic pump 26p is a variable displacement hydraulic pump whose discharge capacity and the like are controlled by the swash plate angle, and the supply direction according to the swash plate angle is controlled by the right servo piston 26c. And the pressure oil is supplied to the right traveling hydraulic motor 26R by the supply amount, and the right traveling hydraulic motor 26R is rotationally driven.

  The left servo piston 27c includes a forward pilot port 27f and a reverse pilot port 27r, and an internal piston (not shown) corresponding to the pilot pressure acting on the forward pilot port 27f and the reverse pilot port 27r. Has been moved. The left hydraulic pump 27p is a variable displacement hydraulic pump whose discharge capacity is controlled by the swash plate angle, and the supply direction corresponding to the swash plate angle is controlled by the left servo piston 27c controlling the swash plate angle. Then, pressure oil is supplied to the left traveling hydraulic motor 27L with the supplied amount, and the left traveling hydraulic motor 27L is rotationally driven.

  The arm cylinder control valve 28c is configured to include a spool (not shown) movably inside, and is provided with an ascending pilot port 28u and a descending pilot port 28d at its ends. Therefore, the spool is moved in accordance with the pilot pressure acting on the ascending pilot port 28u and the descending pilot port 28d, so that the pressure oil from the working machine hydraulic pump 80 is supplied in a direction corresponding to the spool moving position. Then, the supplied amount is supplied to the arm cylinder 28 to be expanded and contracted.

  The bucket cylinder control valve 29c includes a spool (not shown) movably inside, and is provided with an excavation side pilot port 29k and a dump side pilot port 29d at the ends. Therefore, the spool is moved according to the pilot pressure acting on the excavation side pilot port 29k and the dump side pilot port 29d, so that the pressure oil from the work machine hydraulic pump 80 is supplied in a direction corresponding to the moving position of the spool. Then, the supplied amount is supplied to the arm cylinder 28 to be expanded and contracted.

  As shown in FIG. 6, the combination switching valve 50 is formed in a columnar shape as a whole, and is formed into a cylindrical valve body portion 57 and a columnar shape and slides inside the valve body portion 57. The oil passage switching unit 58 is rotatably inserted. As shown in FIG. 5, the valve main body 57 is provided with six input ports 51 to 56 and six output ports 61 to 66. The oil passage switching portion 58 is formed with a connecting oil passage for connecting each of the input side ports 51 to 56 to any one of the output side ports 61 to 66, and a valve main body portion 57 at the axial end portion. On the other hand, a rotation operation lever 59 for rotating the oil passage switching unit 58 is provided.

  FIG. 6 schematically shows an example of a connecting oil passage formed in the oil passage switching portion 58, and FIG. 6A shows an example in which a through hole 58a as a connecting oil passage is formed. FIG. 6B shows an example in which a groove portion 58b as a connecting oil passage is formed. In the oil passage switching portion 58, a connection oil passage is formed by combining a plurality of oil passages such as the through hole 58a and the groove portion 58b.

  In a state where the oil passage switching portion 58 is located at the first rotational position corresponding to the first operation combination with respect to the valve main body portion 57, as shown in FIGS. 3 and 5, the input side port 51 and the output side Port 61, input side port 52 and output side port 62, input side port 53 and output side port 63, input side port 54 and output side port 64, input side port 55 and output side port 65, input side port 56 and output side Each of the ports 66 is connected to form the hydraulic circuit 2 corresponding to the first operation combination.

  In the state where the oil passage switching unit 58 is rotated, for example, about 45 degrees from the first rotational position and is located at the second rotational position corresponding to the second operation combination, as shown in FIGS. The input side port 51 and the input side port 52 are input to the output side port 65 via the first shuttle valve 71, and the input side port 52 and the input side port 53 are input to the output side port 63 via the second shuttle valve 72. The side port 53 and the input side port 54 are connected to the output side port 66 via the third shuttle valve 73, and the input side port 51 and the input side port 54 are connected to the output side port 61 via the fourth shuttle valve 74. 55 is connected to the direct output side port 64, and the input side port 56 is connected to the direct output side port 62, so that the hydraulic circuit 2 corresponding to the second operation combination is configured. That.

  The constituent members of the hydraulic circuit 2 have been described above. In the hydraulic circuit 2 having such components, the pilot pressure generated by the left pilot valve unit 39 and the right pilot valve unit 49 (excluding the first pilot valve 41 and the third pilot valve 43) is temporarily switched in combination. It is inputted to the valve 50 and outputted from the combination switching valve 50 to the right servo piston 26c, the left servo piston 27c and the arm cylinder control valve 28c.

  Here, the connection state on the input side of the combination switching valve 50 will be described. The input side port 51 of the combination switching valve 50 and the first pilot valve 31 of the left pilot valve unit 39 are connected by the first input line 31a. The side port 52 and the second pilot valve 32 are connected by the second input line 32a, the input side port 53 and the third pilot valve 33 are connected by the third input line 33a, and the input side port 54 and the fourth pilot valve are connected. 34 is connected by the fourth input line 34a, the input side port 55 and the second pilot valve 42 of the right pilot valve unit 49 are connected by the fifth input line 42a, and the input side port 56 and the fourth pilot valve 44 are connected to each other. Are connected by a sixth input line 44a.

  On the other hand, the output side connection state of the combination switching valve 50 will be described. The output side port 61 of the combination switching valve 50 and the reverse side pilot port 27r of the left servo piston 27c are connected by the first output line 61a. 62 and the forward pilot port 26f of the right servo piston 26c are connected by a second output line 62a, and the output side port 63 and the forward pilot port 27f of the left servo piston 27c are connected by a third output line 63a for output. The side port 64 and the reverse pilot port 26r of the right servo piston 26c are connected by a fourth output line 64a, and the output side port 65 and the ascending pilot port 28u of the arm cylinder control valve 28c are connected by a fifth output line 65a. Connected and output And lowering side pilot port 28d of the port 66 and the arm cylinder control valve 28c is connected by the sixth output line 66a.

  The excavation side pilot port 29k of the bucket cylinder control valve 29c and the third pilot valve 43 of the right pilot valve unit 49 are connected by a seventh input line 43a, and the dump side pilot port 29d of the bucket cylinder control valve 29c. And the first pilot valve 41 of the right pilot valve unit 49 are connected by an eighth input line 41a. That is, the pilot pressures generated by the first pilot valve 41 and the third pilot valve 43 are directly input to the bucket cylinder control valve 29c without being input to the combination switching valve 50.

  In the hydraulic circuit 2 configured as described above, the operation of the hydraulic actuator when the left operation lever 30 and the right operation lever 40 are tilted is set to the first operation combination and the second operation combination. This will be described in detail below.

  First, the case where the first operation combination is set will be described with reference to FIG. When the left operating lever 30 is tilted forward, pilot pressure is generated in the second pilot valve 32 and the third pilot valve 33, and the pilot pressure generated in the second pilot valve 32 is the second input line 32a and the second input valve 32a. It is output to the forward pilot port 26f via the output line 62a, and the pilot pressure generated by the third pilot valve 33 is output to the forward pilot port 27f via the third input line 33a and the third output line 63a. Is done. As a result, the right traveling hydraulic motor 26R and the left traveling hydraulic motor 27L are rotationally driven forward, and the skid steer loader 1 travels forward.

  When the left operating lever 30 is tilted rearward, pilot pressure is generated in the first pilot valve 31 and the fourth pilot valve 34, and the pilot pressure generated in the first pilot valve 31 is the first input line 31a and the first pilot valve 31. It is output to the reverse pilot port 27r via the output line 61a, and the pilot pressure generated by the fourth pilot valve 34 is output to the reverse pilot port 26r via the fourth input line 34a and the fourth output line 64a. Is done. As a result, the right traveling hydraulic motor 26R and the left traveling hydraulic motor 27L are driven to rotate backward, and the skid steer loader 1 travels backward.

  When the left operating lever 30 is tilted to the right, the pilot pressure is generated in the third pilot valve 33 and the fourth pilot valve 34, and the pilot pressure generated in the third pilot valve 33 is the third input line 33a and the second pilot valve 33. The pilot pressure generated by the fourth pilot valve 34 is output to the forward pilot port 26r via the third output line 63a, and the pilot pressure generated by the fourth pilot valve 34 is supplied to the reverse pilot port 26r via the fourth input line 34a and the fourth output line 64a. Is output. As a result, the right traveling hydraulic motor 26R is driven to rotate backward and the left traveling hydraulic motor 27L is driven to rotate forward, so that the skid steer loader 1 turns rightward (right spin turn).

  When the left operating lever 30 is tilted to the left, pilot pressure is generated in the first pilot valve 31 and the second pilot valve 32, and the pilot pressure generated in the first pilot valve 31 is the first input line 31a and the first pilot valve 31. The pilot pressure output to the reverse pilot port 27r via the first output line 61a and the pilot pressure generated by the second pilot valve 32 passes to the forward pilot port 26f via the second input line 32a and the second output line 62a. Is output. As a result, the right traveling hydraulic motor 26R is driven to rotate forward, the left traveling hydraulic motor 27L is driven to rotate backward, and the skid steer loader 1 is spun toward the left front (left spin turn).

  Further, the first pilot valve 31 is tilted to the rear left side, the second pilot valve 32 is tilted to the front left side, the third pilot valve 33 is tilted to the front right side, and the rear side. When tilted to the right, pilot pressure is generated in the fourth pilot valve 34 and output to the corresponding hydraulic actuator. For example, when the left operating lever 30 is tilted rearward and leftward, only the first pilot valve 31 is pressed by the left operating lever 30, and the pilot pressure generated by the first pilot valve 31 is applied to the reverse pilot port 27r. Is output. As a result, the left traveling hydraulic motor 27L is driven to rotate backward, and only the left crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels backward.

  When the right operating lever 40 is tilted forward, a pilot pressure is generated in the fourth pilot valve 44, and this pilot pressure is output to the descending pilot port 28d via the sixth input line 44a and the sixth output line 66a. Is done. As a result, the arm cylinder 28 is reduced and the arm 21 is swung downward.

  When the right operation lever 40 is tilted rearward, a pilot pressure is generated in the second pilot valve 42, and this pilot pressure is output to the ascending pilot port 28u via the fifth input line 42a and the fifth output line 65a. Is done. As a result, the arm cylinder 28 is extended and the arm 21 is swung upward.

  When the right operating lever 40 is tilted to the right, a pilot pressure is generated in the first pilot valve 41, and this pilot pressure is output to the dump side pilot port 29d via the eighth input line 41a. As a result, the bucket cylinder 29 is extended, and the bucket cylinder 29 is swung downward (in the dump direction).

  When the right operating lever 40 is tilted to the left, a pilot pressure is generated in the third pilot valve 43, and this pilot pressure is output to the excavation side pilot port 29k via the seventh input line 43a. As a result, the bucket cylinder 29 is reduced and the bucket cylinder 29 is swung upward (in the excavation direction).

  Next, the case where the second operation combination is set will be described with reference to FIGS. 4 and 5. When the left operating lever 30 is tilted forward, pilot pressure is generated in the second pilot valve 32 and the third pilot valve 33, and these pilot pressures are input to the input side ports 52 and 53 of the combination switching valve 50. . Of the pilot pressures input to the input ports 52 and 53, a high pilot pressure is output to the forward pilot port 27f via the second shuttle valve 72, the output port 63 and the third output line 63a. . As a result, the left traveling hydraulic motor 27L is rotationally driven forward, and only the left crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels forward.

  At this time, part of the pilot pressure generated by the second pilot valve 32 and input to the input side port 52 of the combination switching valve 50 is the first shuttle valve 71, the output side port 65, and the fifth output line. It is output to the ascending pilot port 28u via 65a. Part of the pilot pressure generated by the third pilot valve 33 and input to the input side port 53 of the combination switching valve 50 passes through the third shuttle valve 73, the output side port 66, and the sixth output line 66a. And output to the descending pilot port 28d. Since the pilot pressures input to the ascending pilot port 28u and the descending pilot port 28d have substantially the same magnitude, the spool of the arm cylinder control valve 28c is held in the neutral position.

  When the left operating lever 30 is tilted rearward, pilot pressure is generated in the first pilot valve 31 and the fourth pilot valve 34, and these pilot pressures are input to the input-side ports 51 and 54 of the combination switching valve 50. . Of the pilot pressures input to the input ports 51 and 54, a high pilot pressure is output to the reverse pilot port 27r via the fourth shuttle valve 74, the output port 61 and the first output line 61a. . As a result, the left traveling hydraulic motor 27L is driven to rotate backward, and only the left crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels backward.

  At this time, part of the pilot pressure generated by the first pilot valve 31 and input to the input side port 51 of the combination switching valve 50 is the first shuttle valve 71, the output side port 65, and the fifth output line. It is output to the ascending pilot port 28u via 65a. A part of the pilot pressure generated by the fourth pilot valve 34 and input to the input side port 54 of the combination switching valve 50 passes through the third shuttle valve 73, the output side port 66, and the sixth output line 66a. And output to the descending pilot port 28d. Since the pilot pressures input to the ascending pilot port 28u and the descending pilot port 28d have substantially the same magnitude, the spool of the arm cylinder control valve 28c is held in the neutral position.

  When the left operating lever 30 is tilted to the right, pilot pressure is generated in the third pilot valve 33 and the fourth pilot valve 34, and these pilot pressures are input to the input-side ports 53 and 54 of the combination switching valve 50. The Of the pilot pressures input to the input ports 53 and 54, a high pilot pressure is output to the descending pilot port 28d via the third shuttle valve 73, the output port 66 and the sixth output line 66a. . As a result, the arm cylinder 28 is reduced and the arm 21 is swung downward.

  At this time, part of the pilot pressure generated by the third pilot valve 33 and input to the input side port 53 of the combination switching valve 50 is the second shuttle valve 72, the output side port 63, and the third output line. It is output to the forward pilot port 27f via 63a. A part of the pilot pressure generated by the fourth pilot valve 34 and input to the input side port 54 of the combination switching valve 50 passes through the fourth shuttle valve 74, the output side port 61, and the first output line 61a. And output to the reverse pilot port 27r. The pilot pressures input to the forward pilot port 27f and the reverse pilot port 27r have substantially the same magnitude, and the left servo piston 27c regulates the supply of pressure oil from the left hydraulic pump 27p to the left traveling hydraulic motor 27L. The left traveling hydraulic motor 27L is not driven to rotate.

  When the left operating lever 30 is tilted to the left, pilot pressure is generated in the first pilot valve 31 and the second pilot valve 32, and these pilot pressures are input to the input side ports 51 and 52 of the combination switching valve 50. The Of the pilot pressures input to the input ports 51 and 52, a high pilot pressure is output to the ascending pilot port 28u via the first shuttle valve 71, the output port 65, and the fifth output line 65a. . As a result, the arm cylinder 28 is extended and the arm 21 is swung upward.

  At this time, part of the pilot pressure generated by the first pilot valve 31 and input to the input side port 51 of the combination switching valve 50 is the fourth shuttle valve 74, the output side port 61, and the first output line. It is output to the reverse side pilot port 27r via 61a. A part of the pilot pressure generated by the second pilot valve 32 and input to the input side port 52 of the combination switching valve 50 passes through the second shuttle valve 72, the output side port 63, and the third output line 63a. And output to the forward pilot port 27f. The pilot pressures input to the reverse pilot port 27r and the forward pilot port 27f have substantially the same magnitude, and the left servo piston 27c restricts the supply of pressure oil from the left hydraulic pump 27p to the left traveling hydraulic motor 27L. The left traveling hydraulic motor 27L is not driven to rotate.

  Further, the first pilot valve 31 is tilted to the rear left side, the second pilot valve 32 is tilted to the front left side, the third pilot valve 33 is tilted to the front right side, and the rear side. When tilted to the right, pilot pressure is generated in the fourth pilot valve 34 and output to the corresponding hydraulic actuator. For example, when the left operating lever 30 is tilted rearward and leftward, only the first pilot valve 31 is pressed by the left operating lever 30, and the pilot pressure generated by the first pilot valve 31 is changed to the reverse pilot port 27r. And the ascending pilot port 28u. As a result, the left traveling hydraulic motor 27L is driven to rotate backward, and only the left crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels backward, and the arm cylinder 28 is extended to move the arm 21 upward. It is swung.

  When the right operating lever 40 is tilted forward, a pilot pressure is generated in the fourth pilot valve 44, and this pilot pressure passes through the input side port 56, the output side port 62, and the second output line 62a, and the forward side pilot. Output to port 26f. As a result, the right traveling hydraulic motor 26L is rotationally driven forward, and only the right crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels forward.

  When the right operating lever 40 is tilted rearward, a pilot pressure is generated in the second pilot valve 42, and this pilot pressure passes through the input side port 55, the output side port 64, and the fourth output line 64a, and the reverse side pilot. Output to port 26r. As a result, the right traveling hydraulic motor 26L is driven to rotate backward, and only the right crawler mechanism 16 of the pair of left and right crawler mechanisms 16 travels backward.

  Note that when the right operating lever 40 is tilted to the right and when the right operating lever 40 is tilted to the left, it is the same as the case where the first operating combination is set, so here The description in is omitted.

  Thus, for each of the left operating lever 30 and the right operating lever 40, a combination of a tilting operation and a hydraulic actuator (control valve) that operates in accordance with the tilting operation connects the pilot valve and the control valve. It is configured to be set by the connection pattern of the sixth input line and the first to sixth output lines. Therefore, by interposing the combination switching valve 50 between the first to sixth input lines and the first to sixth output lines, the connection pattern can be switched according to the rotational position of the oil path switching unit 58. It has become.

  The operation of the hydraulic actuator when the left operation lever 30 and the right operation lever 40 are tilted has been described above. As described above, the skid steer loader 1 to which the present invention is applied generates, for example, two pilot pressures simultaneously when the left operating lever 30 is tilted back and forth and left and right in the first operation combination, It is set to perform a desired work by simultaneously operating two hydraulic actuators. On the other hand, when the left operating lever 30 is tilted with respect to the front, rear, left and right, one pilot pressure is generated and one hydraulic actuator is operated to perform a desired operation. Is set. As described above, the skid steer loader 1 is configured to perform a desired operation by combining a setting for generating one pilot pressure and a setting for generating two pilot pressures according to the tilting direction of the operation lever. It has become. Therefore, various operation combinations can be set in comparison with a configuration in which one pilot pressure is generated and a desired work is performed in response to tilting operation to the front, rear, left and right with respect to the operation lever. Can increase the degree of freedom. Furthermore, by providing the combination switching valve 50, it is possible to easily switch between the two operation combinations, and it is possible to configure the skid steer loader 1 with high convenience.

  Further, in the skid steer loader 1, when the left operation lever 30 is tilted forward, for example, the left operation lever 30 is supported at the root portion thereof, the second pilot valve 32 and the third pilot valve 33. ing. Therefore, even when the vehicle body 10 is greatly shaken by running on a road with large unevenness, the tilting position of the left operation lever 30 can be stably held.

  In the above-described embodiment, the pilot valves 31 to 34 and 41 to 44 of the type that generate the pilot pressure by being pressed according to the tilting operation with respect to the left operation lever 30 and the right operation lever 40 have been described as examples. The pilot valve is not limited to this type. For example, a pilot valve that generates a pilot pressure by being pulled according to a tilting operation on the left operating lever 30 and the right operating lever 40 may be used.

  In the above-described embodiment, the left pilot valve unit 39 in which the four pilot valves 31 to 34 are rotated by about 45 degrees with respect to the front, rear, left, and right as the predetermined operation direction has been described. The arrangement of the unit 39 is not limited to this. When the left operating lever 30 is tilted back and forth and left and right, pilot pressure may be generated by two (a plurality of) pilot valves corresponding to the tilting operation, that is, the tilting center of the left operating lever 30 ( It is only necessary that the pilot valves are arranged at positions symmetrical with respect to a reference line extending in the front, rear, left, and right through the root portion).

  In the embodiment described above, the oil passage switching unit 58 is rotated about 45 degrees with respect to the valve main body 57, and the first rotation position corresponding to the first operation combination and the second operation combination corresponding to the second operation combination. The combination switching valve 50 that switches to the second rotational position has been described as an example, but the combination switching valve 50 is not limited to this configuration. For example, a spool may be inserted movably inside the main body, and the first operation combination and the second operation combination may be switched according to the movement position of the spool.

  In the above-described embodiment, the configuration in which the pair of the left operation lever 30 and the right operation lever 40 is provided on the left and right of the operator seat 13 has been described as an example. However, the present invention is not limited to this configuration. . For example, the present invention can be applied to a configuration in which an operation lever is provided only on either the left or right side of the operator seat 13.

  In the above-described embodiment, the configuration example in which the present invention is applied to the skid steer loader as an example of the work machine has been described. However, the present invention is not limited to the skid steer loader, but a bulldozer, a power shovel, or the like. The same effect can be obtained in the same way.

  In the above-described embodiment, the configuration in which the swash plate angle of the right hydraulic pump 26p is controlled by the right servo piston 26c and the swash plate angle of the left hydraulic pump 27p is controlled by the left servo piston 27c, respectively. The present invention is not limited to the configuration. For example, a control valve is used in place of the right servo piston 26c and the left servo piston 27c so that the swash plate angle is controlled according to the moving position of the spool moved by the pilot pressure. Similarly, the present invention can be applied.

1 Skid steer loader (work machine)
16 Crawler mechanism (working device, traveling device)
21 Arm (Working device)
22 bucket (working equipment)
26R right traveling hydraulic motor (hydraulic actuator, traveling hydraulic motor)
26c Right servo piston (control means)
27L Left traveling hydraulic motor (hydraulic actuator, traveling hydraulic motor)
27c Left servo piston (control means)
28 Arm cylinder (hydraulic actuator)
28c Arm cylinder control valve (control means)
29 Bucket cylinder (hydraulic actuator)
29c Bucket cylinder control valve (control means)
30 Left control lever (control lever)
31-34 First to fourth pilot valves (pilot valves)
31a to 34a First to fourth input lines (pilot oil passages)
40 Right control lever (control lever)
41 to 44 First to fourth pilot valves (pilot valves)
42a 5th input line (pilot oil passage)
44a 6th input line (pilot oil passage)
50 Combination switching valve (connection pattern switching means)
61a to 66a First to sixth output lines (pilot oil passages)
71-74 First to fourth shuttle valves (shuttle valves)

Claims (6)

A plurality of hydraulic actuators for operating the work device;
A plurality of control means which are provided corresponding to the plurality of hydraulic actuators and control the supply of pressure oil to the hydraulic actuators;
A work machine having pilot pressure generating means for generating a plurality of pilot pressures for controlling the operation of the control means,
The pilot pressure generating means includes an operation lever that can be tilted in a plurality of directions, and a plurality of pilot valves that generate a plurality of pilot pressures corresponding to the tilting operation of the operation lever.
A plurality of pilot pressures generated by the pilot valve are transmitted to the control means via a plurality of pilot oil passages connecting the pilot valve and the control means, thereby controlling the operation of the control means,
Depending on the connection pattern between the plurality of pilot valves and the plurality of control means by the plurality of pilot oil passages, the tilting operation with respect to the operation lever in a predetermined direction set in advance and the tilting operation in the predetermined direction are performed. A combination with the control means to be activated is set,
A first switching oil passage connecting the pilot valve and the control means to the pilot oil passage with a first connection pattern; and a second connection pattern different from the first connection pattern; Comprising a connection pattern switching means formed with a second switching oil passage connecting the control means;
The pilot pressure generating means is configured to be able to generate a plurality of pilot pressures by simultaneously operating the plurality of pilot valves in accordance with a tilting direction in the tilting operation of the operation lever. Work machine.   2. The work machine according to claim 1, wherein the pilot valves are respectively disposed at positions symmetrical with respect to a reference line extending in the predetermined direction through a tilt center of the operation lever.   One of the first switching oil passage and the second switching oil passage is configured to include a shuttle valve that selectively transmits a high-pressure side pilot pressure among a plurality of pilot pressures. The work machine according to claim 1 or 2, wherein Two pilot pressure generating means are provided,
Each of the pilot pressure generation means includes the operation lever and the plurality of pilot valves,
The plurality of pilot valves and the plurality of control means in each of the pilot pressure generating means are connected by the plurality of pilot oil passages,
Each of the single pilot pressures generated by the plurality of pilot valves in each of the pilot pressure generation means is configured to be transmitted to the plurality of control means via the plurality of pilot oil passages,
The work according to claim 1, wherein the connection pattern switching unit switches the first connection pattern and the second connection pattern by switching a plurality of the pilot oil passages. machine. When the operation lever in each of the pilot pressure generating means is tilted in the same direction in the predetermined direction,
One of the pilot pressure generating means generates a single pilot pressure in the plurality of pilot valves,
5. The work machine according to claim 4, wherein the other pilot pressure generating means simultaneously generates a plurality of pilot pressures in the plurality of pilot valves. The working device includes a traveling device that travels a vehicle body, an arm that is swingable up and down with respect to the vehicle body, and a bucket that is swingable up and down at a tip portion of the arm. Configured,
The hydraulic actuator includes a traveling hydraulic motor that operates the traveling device, an arm cylinder that swings the arm, and a bucket cylinder that swings the bucket. The work machine according to any one of 5.

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