Wheel construction machinery

Abstract

The control device of the wheel-type hydraulic shovel controls the flow of hydraulic fluid from the hydraulic cylinder that drives the working device, and executes the control of a vibration suppression function that suppresses vibration of the hydraulic cylinder when the rotational speed of the wheel reaches a predetermined level or higher. In addition, even when the effective control of the vibration suppression function is indicated by the vibration suppression indicator device, the control of the vibration suppression function is disabled when the vehicle body is jacked up by the working device.

Description

Technology Field

[0001] The present invention relates to a wheeled construction machine, and more specifically, to a wheeled construction machine equipped with a vibration suppression function that suppresses vibration during driving. Background Technology

[0002] It is known that among wheeled construction machines, such as wheeled hydraulic shovels or wheel loaders, an accumulator is used to suppress vibration during driving (see, for example, Patent Document 1). In the hydraulic circuit for damping driving vibration of a wheeled construction machine described in Patent Document 1, an accumulator for damping vibration is connected to the bottom side of a hydraulic cylinder that drives a work device composed of a boom or bucket, etc., through an opening / closing valve, and the head side of the said hydraulic cylinder is connected to an oil tank through another opening / closing valve. When the switching switch is turned on by an operator during driving and the vehicle speed becomes greater than a predetermined vehicle speed, the said opening / closing valve is switched to an open state, thereby connecting the accumulator and the bottom side of the hydraulic cylinder, and connecting the head side of the hydraulic cylinder to the oil tank. As a result, even if the wheeled construction machine vibrates vertically due to driving, the energy of the vertical vibration of the working device is absorbed and damped by the accumulator, thereby damping the vertical vibration during driving. Prior art literature

[0003] Japanese Patent Publication No. Hei 11-36375 The problem to be solved

[0004] However, in the case of wheeled construction machinery, when moving from a work site to a public road, there are instances where the wheels are left idle while the working device is grounded to the ground and the machine is lifted by jacking up. However, in the technology described in Patent Document 1, if the switching switch for driving vibration damping is already turned ON when moving from the work site (when driving begins), when the rotational speed of the wheels being left idle reaches a predetermined level or higher, the function for damping vibration during driving (driving vibration damping function) may be switched to an operating state (open state of the shut-off valve). In this case, since the head side of the hydraulic cylinder becomes connected to the oil tank, the hydraulic fluid from the head side of the hydraulic cylinder is discharged into the oil tank, and it may become impossible to maintain the jack-up state. Therefore, in order to prevent the leakage of hydraulic fluid from the head side of the hydraulic cylinder to the oil tank during the jack-up, it is necessary to switch the switching switch for driving vibration damping to OFF before performing the jack-up. Furthermore, when resuming driving and moving onto a public road after the jack-up is completed, the driving vibration damping function cannot be activated unless the corresponding switch is turned back to ON. As such, the operator needs to individually switch the switch for the driving vibration damping function according to various situations.

[0005] The present invention was made to resolve the aforementioned problems, and its purpose is to provide a wheeled construction machine capable of reducing the inconvenience of operating a switching switch for a driving vibration suppression function. means of solving the problem

[0006] The present invention comprises a plurality of means for solving the above problem, and as an example, a wheeled construction machine comprising a self-propelled vehicle body equipped with wheels, a work device installed on the vehicle body, a control device that controls the flow of hydraulic fluid from a hydraulic cylinder driving the work device to suppress vibration of the hydraulic cylinder when the rotational speed of the wheels reaches a predetermined level or higher, and a vibration suppression indicator device that indicates the validity or invalidity of the control of the vibration suppression function by the control device, wherein the control device is characterized by invalidating the control of the vibration suppression function when the vehicle body is in a state where it is jacked up by the work device, even when the validity of the control of the vibration suppression function is indicated by the vibration suppression indicator device. Effects of the invention

[0007] According to the present invention, even when the effective control of the vibration suppression function is indicated by the vibration suppression indicator device, the control of the vibration suppression function becomes ineffective when the vehicle body is jacked up by the working device, so the operator does not need to perform an operation to indicate the ineffective control of the vibration suppression function to the vibration suppression indicator device. In other words, the inconvenience of operating the vibration suppression indicator device can be reduced.

[0008] Other tasks, configurations, and effects other than those mentioned above will be revealed by the description of the embodiments below. Brief explanation of the drawing

[0009] FIG. 1 is a perspective view showing a wheeled hydraulic shovel in a partially transparent state as a first embodiment of the wheeled construction machine of the present invention. FIG. 2 is a drawing illustrating equipment inside a cabin in a wheeled construction machine according to the first embodiment shown in FIG. 1. FIG. 3 is a circuit diagram illustrating the schematic configuration of a hydraulic system and a block diagram illustrating the schematic configuration of a driving system in a wheeled construction machine according to the first embodiment shown in FIG. 1. FIG. 4 is a block diagram illustrating the function of a control device in a wheeled construction machine according to the first embodiment shown in FIG. 1. FIG. 5 is an explanatory diagram illustrating a load hanging operation when the control device of a wheeled construction machine according to the first embodiment shown in FIG. 4 performs overload alarm control. FIG. 6 is a flowchart showing an example of a processing procedure for ride control in a control device of a wheeled construction machine according to the first embodiment shown in FIG. 4. FIG. 7 is a drawing illustrating the jack-up operation in a wheeled construction machine according to the first embodiment shown in FIG. 1. FIG. 8 is a circuit diagram illustrating the schematic configuration of a hydraulic system and a block diagram illustrating the schematic configuration of a driving system in a wheeled construction machine according to a second embodiment of the present invention. Specific details for implementing the invention

[0010] Hereinafter, embodiments of the wheeled construction machine of the present invention will be described using drawings. In this description, a wheeled hydraulic shovel is exemplified as an embodiment of the wheeled construction machine of the present invention.

[0011] [First Embodiment]

[0012] First, the configuration of a wheeled hydraulic shovel as a first embodiment of the wheeled construction machine of the present invention will be explained using FIGS. 1 and 2. FIGS. 1 is a perspective view showing a wheeled hydraulic shovel as a first embodiment of the wheeled construction machine of the present invention in a partially transparent state. FIGS. 2 is a drawing showing equipment inside the cabin of the wheeled construction machine according to the first embodiment shown in FIGS. 1.

[0013] In FIG. 1, the wheeled hydraulic shovel (1) (hereinafter referred to as the hydraulic shovel (1)) is equipped with a wheeled vehicle body (2) that can be driven as a vehicle body, a swivel body (3) mounted rotatably on the vehicle body (2), and a front work device (4) provided on the front part of the swivel body (3) so as to be driven (movable) in an up-and-down direction. The hydraulic shovel (1) can perform excavation work, etc., at a work site using the front work device (4), and can move from the work site by the wheeled vehicle body (2) to drive on public roads. In addition, the hydraulic shovel (1) can also be configured with a soil-pulling blade (5) installed at the rear end of the vehicle body (2) (see FIG. 7 described later). The soil-pulling blade (5) is used for soil plowing or leveling the ground. The hydraulic shovel (1) can perform the jack-up operation described later by using the front work device (4) or the soil-pulling blade (5).

[0014] The driving body (2) is equipped with a frame (11) extending in the front and rear directions, left and right front wheels (13) (only the left side is shown) installed via an axle (12) on the front side of the frame (11) as driving wheels, and left and right rear wheels (15) installed via an axle (14) on the rear side of the frame (11) as driving wheels. A driving hydraulic motor (17) and a transmission (18) are mounted on the frame (11).

[0015] The axles (12) and (14) each rotatably support the front wheel (13) and rear wheel (15) and transmit the rotational driving force of the driving hydraulic motor (17) to the front wheel (13) and rear wheel (15), and include a differential mechanism that distributes the rotational driving force to the left and right wheels. The axles (12) and (14) are installed to be oscillating with respect to the frame (11). That is, the axles (12) and (14) are configured to be oscillating with respect to the slewing body (3) which serves as the vehicle body. Additionally, it is possible to configure the rotational driving force of the driving hydraulic motor (17) to be transmitted to only one of the front wheel (13) or the rear wheel (15). Furthermore, it is also possible to configure the axles (12) and (14) so ​​that only one of them is installed to be oscillating with respect to the frame (11), while the other is fixed.

[0016] The slewing body (3) is configured to slewing drive relative to the frame (11) of the vehicle body (2) by means of a slewing hydraulic motor (6). The slewing body (3) includes a driver's cab (21) where an operator sits, a machine room (22) for housing various devices, and a counterweight (23) for balancing with the front work device (4). In the driver's cab (21), as shown in FIG. 2, a driver's seat (25) where an operator sits, an operating device (26) for outputting operation instructions for the front work device (4), an accelerator pedal (27), a brake pedal (28), and a steering wheel (29) for operating the vehicle body (2) are arranged. The operating device (26) is, for example, an operating lever device that directs the operation of the front work device (4) according to lever operation, and has a left operating lever (26a) and a right operating lever (26b). The left operating lever (26a) and the right operating lever (26b) are assigned the respective operations of the boom (41), arm (42), and bucket (43) described later, which constitute the front working device (4). The steering (29) is for steering the front wheel (13). In the cab (21), the ride control switch (31) (hereinafter referred to as the RC switch), the overload alarm switch (32), and the monitor (33) (all refer to FIG. 4) described later are arranged. In the machine room (22), for example as shown in FIG. 1, an engine (35) as a prime mover, a hydraulic pump (51), a control valve unit (53), a hydraulic fluid tank (57), etc. are housed.

[0017] The front work device (4) is a multi-jointed work device for performing excavation work, etc., and is equipped with, for example, a boom (41), an arm (42), and a bucket (43) as an attachment. The boom (41) is rotatably connected to the front part of the slewing body (3). The arm (42) is rotatably connected to the front end of the boom (41). The bucket (43) is rotatably connected to the front end of the arm (42). The boom (41), arm (42), and bucket (43) are each driven by a boom cylinder (45), an arm cylinder (46), and a bucket cylinder (47), which are hydraulic actuators.

[0018] Next, the configuration of the hydraulic system and the driving system in the first embodiment of the wheeled construction machine of the present invention will be explained using FIG. 3. FIG. 3 is a circuit diagram illustrating the schematic configuration of the hydraulic system and the schematic configuration of the driving system in the wheeled construction machine according to the first embodiment shown in FIG. 1.

[0019] In FIG. 3, the hydraulic system of the hydraulic shovel (1) is equipped with a hydraulic pump (51) that is driven by an engine (35) as a prime mover and discharges hydraulic fluid, a plurality of hydraulic actuators driven by hydraulic fluid supplied from the hydraulic pump (51), and a control valve unit (53) which is a collection of control valves that control the flow (direction and flow rate) of hydraulic fluid supplied from the hydraulic pump (51) to each of the plurality of hydraulic actuators.

[0020] In FIG. 3, only the driving hydraulic motor (17) driven during driving and the boom cylinder (45) related to ride control are shown as hydraulic actuators. The hydraulic circuits of other hydraulic actuators (slewing hydraulic motor (6), arm cylinder (46), bucket cylinder (47), etc.) are omitted.

[0021] The boom cylinder (45) has a cylinder body (45a), a piston (45b) slidably disposed within the cylinder body (45a), and a piston rod (45c) extending from one side of the piston (45b). The interior of the cylinder body (45a) is partitioned into a first oil chamber (Cb) and a second oil chamber (Cr) by the piston (45b). The first oil chamber (Cb) is an oil chamber to which pressurized oil from a hydraulic pump (51) is supplied when driving the boom (41) (front work device (4)) in an upward direction. Meanwhile, the second oil chamber (Cr) is an oil chamber to which pressurized oil from a hydraulic pump (51) is supplied when driving the boom (41) (front work device (4)) in a downward direction. That is, when pressurized oil is supplied to the first oil chamber (Cb), the boom cylinder (45) extends to drive the boom (41) in an upward direction. Meanwhile, when hydraulic oil is supplied to the second oil chamber (Cr), it shortens, thereby driving the boom (41) downward. The weight of the boom (41) (front work device (4)) acts on the first oil chamber (Cb). Hereinafter, the first oil chamber (Cb) and the second oil chamber (Cr) are referred to as the bottom chamber and the rod chamber, respectively.

[0022] The control valve unit (53) is connected to the bottom seal (Cb) side of the boom cylinder (45) through the first actuator line (54) and the hose rupture valve (56) (hereinafter referred to as the HR valve), and is also connected to the rod seal (Cr) side of the boom cylinder (45) through the second actuator line (55). The first actuator line (54) is a hydraulic line that directs the hydraulic fluid of the hydraulic pump (51) to the bottom seal (Cb) of the boom cylinder (45) through the control valve unit (53). The second actuator line (55) is a hydraulic line that directs the hydraulic fluid of the hydraulic pump (51) to the rod seal (Cr) of the boom cylinder (45) through the control valve unit (53).

[0023] The HR valve (56) is installed between the bottom seal (Cb) of the boom cylinder (45) and the first actuator line (54), and has the function of preventing the leakage of hydraulic fluid from the bottom seal (Cb) of the boom cylinder (45) to the first actuator line (54) when the first actuator line (54) breaks. By doing so, it prevents the boom (41) from falling when the first actuator line (54) breaks. The HR valve (56) has a poppet valve (81) that prevents the leakage of hydraulic fluid from the bottom seal (Cb) of the boom cylinder (45) when the first actuator line (54) breaks, a pilot valve (82) that drives the poppet valve (81), and a small relief valve (83) that has an overload relief function. The HR valve (56) has a poppet valve (81), a pilot valve (82), and a small relief valve (83) housed in a housing (84).

[0024] The poppet valve (81) has a valve body (85) slidably disposed within a housing (84). The poppet valve (81) has a pipe connection chamber (86) connected to a first actuator line (54), a cylinder connection chamber (87) connected to a bottom chamber (Cb) of a boom cylinder (45), and a back pressure chamber (88) provided on the opposite side of the pipe connection chamber (86) with the valve body (85) in between. The valve body (85) is provided with a throttle communication passage (85a) that communicates the cylinder connection chamber (87) and the back pressure chamber (88). The poppet valve (81) is configured so that the valve body (85) moves according to the balance of the force exerted by the pressure of the pipe connection chamber (86) and the cylinder connection chamber (87), the pressure of the back pressure chamber (88), and the pressing force of the spring (89), thereby switching the connection or blockage of the pipe connection chamber (86) and the cylinder connection chamber (87).

[0025] The pipe connection room (86) and back pressure room (88) of the poppet valve (81) are connected through the first connection passage (91), the pilot valve (82), and the second connection passage (92). The pipe connection room (86) and the cylinder connection room (87) of the poppet valve (81) are connected through the first connection passage (91), the pilot valve (82), and the third connection passage (93). The cylinder connection room (87) of the poppet valve (81) (bottom room (Cb) of the boom cylinder (45)) is connected to the hydraulic fluid tank (57) that stores hydraulic fluid through the relief passage (94).

[0026] The pilot valve (82) has a hydraulic section (82a) in which a release pilot pressure, described later, is induced, and by being displaced according to the release pilot pressure induced in the hydraulic section (82a), it switches between communication or blocking of communication between the first connection passage (91) and the second connection passage (92), and communication or blocking of communication between the first connection passage (91) and the third connection passage (93). In other words, the pilot valve (82) controls the opening and closing of the poppet valve (81) by communication or blocking of communication between the first connection passage (91) and the second connection passage (92), and controls the discharge of hydraulic fluid from the bottom chamber (Cb) of the boom cylinder (45) to the control valve unit (53) that does not pass through the poppet valve (81) by communication or blocking of communication between the first connection passage (91) and the third connection passage (93). The pilot valve (82) is configured to be in a closed position under normal circumstances.

[0027] A small relief valve (83) is provided over the relief passage (94) and is configured to open when the relief passage (94) (cylinder connection chamber (87)) exceeds a set pressure. In the HR valve (56), when the small relief valve (83) is opened, the pilot valve (82) is driven to open the poppet valve (81).

[0028] The hydraulic system also has a configuration that realizes ride control to suppress vibrations during the operation of the hydraulic shovel (1) (when the rotational speed of the wheels (13, 15) reaches a predetermined level or higher). Specifically, it includes an accumulator (58) for ride control. The accumulator (58) absorbs pressure fluctuations in the bottom seal (Cb) of the boom cylinder (45) and is connected to the first actuator line (54), for example, through the first ride control valve (59) (hereinafter referred to as the first RC valve). That is, the accumulator (58) is connected to the bottom seal (Cb) of the boom cylinder (45) through the first RC valve (59) and the HR valve (56). The accumulator (58) and the first actuator line (54) are connected through the first connection line (60), and the first RC valve (59) is provided on the first connection line (60).

[0029] The first RC valve (59) controls the flow of hydraulic fluid (the flow of hydraulic fluid in the first connection line (60)) between the accumulator (58) and the bottom seal (Cb) of the boom cylinder (45), thereby switching the vibration suppression function (i.e., ride control that suppresses vibration during driving) that absorbs pressure fluctuations in the bottom seal (Cb) of the boom cylinder (45) by the accumulator (58) into an operating state or a stopped state. The first RC valve (59) is configured to be switchable to, for example, a first position S that allows the flow of hydraulic fluid from the accumulator (58) to the bottom seal (Cb) of the boom cylinder (45) while blocking the flow of hydraulic fluid from the bottom seal (Cb) of the boom cylinder (45) to the accumulator (58), and a second position R that allows bidirectional flow of hydraulic fluid between the accumulator (58) and the bottom seal (Cb) of the boom cylinder (45). The first position S is a position that stops the ride control by making it impossible to exchange hydraulic fluid between the accumulator (58) and the bottom seal (Cb) of the boom cylinder (45). Meanwhile, the second position R is a position that operates the ride control by making it possible to exchange hydraulic fluid by connecting the accumulator (58) and the bottom seal (Cb) of the boom cylinder (45). The first RC valve (59) is an electronic valve configured to switch to the first position S (stop position of the ride control) during normal operation, for example. The first RC valve (59) is configured to switch according to a command from the control device (100) described later.

[0030] Additionally, the accumulator (58) is connected to the hydraulic fluid tank (57) via a ride control relief valve (61). A relief line (62) is connected to the portion between the accumulator (58) and the first RC valve (59) in the first connection line (60), and a ride control relief valve (61) is provided on the relief line (62). The ride control relief valve (61) defines the upper limit of the pressure of the accumulator (58), and is configured to open the valve when the relief line (62) (accumulator (58)) exceeds the set pressure.

[0031] In the hydraulic system, as a configuration for realizing ride control, the rod seal (Cr) of the boom cylinder (45) is connected to the hydraulic fluid tank (57) through the second ride control valve (63) (hereinafter referred to as the second RC valve). Specifically, the hydraulic fluid tank (57) is connected to the second actuator line (55) through the second connection line (64), and the second RC valve (63) is provided on the second connection line (64).

[0032] The second RC valve (63) controls the flow of hydraulic fluid (pressure fluid flow of the second connection line (64)) between the load seal (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57), thereby switching the vibration suppression function (ride control) by the accumulator (58) to an operating state or a stopped state. The second RC valve (63) is configured to be switchable to, for example, a first position S which allows the flow of hydraulic fluid from the hydraulic fluid tank (57) to the load seal (Cr) of the boom cylinder (45) while blocking the flow of hydraulic fluid from the load seal (Cr) of the boom cylinder (45) to the hydraulic fluid tank (57), and a second position R which allows bidirectional flow of pressure fluid between the load seal (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57). That is, the first position S is a position that stops the ride control by blocking the outflow of hydraulic fluid from the load seal (Cr) of the boom cylinder (45). Meanwhile, the second position R is a position that enables the ride control to operate by connecting the rod seal (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57) to allow the hydraulic fluid to be exchanged. The second RC valve (63) is an electronic valve configured to switch to the first position S (stop position of the ride control) during normal operation, for example. The second RC valve (63) is configured to switch according to a command from the control device (100) described later.

[0033] The first RC valve (59) and the second RC valve (63) of the present embodiment are configured as switching valve devices that switch the vibration suppression function, which absorbs pressure fluctuations in the bottom chamber (Cb) of the boom cylinder (45) by the accumulator (58), to an operating state or a stopped state by controlling the flow of hydraulic fluid between the bottom chamber (Cb) of the boom cylinder (45) and the accumulator (58) and controlling the flow of hydraulic fluid between the rod chamber (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57).

[0034] In other words, the hydraulic shovel (1) includes a vibration suppression function that suppresses vibrations of a wheel (front wheel (13) and rear wheel (15)) installed on a self-propelled body (driving body (2) and slewing body (3)), a work device (e.g., boom (41), arm (42), bucket (43)) installed on the body, and a hydraulic cylinder (e.g., boom cylinder (45)) that drives the work device, when the rotational speed of the wheel (front wheel (13) and rear wheel (15)) reaches a predetermined level or higher.

[0035] Additionally, the hydraulic shovel (1) is provided with a hydraulic pump (hydraulic pump (51)) that supplies hydraulic fluid to a hydraulic cylinder (e.g., boom cylinder (45), arm cylinder (46), bucket cylinder (47)) driving the said work device, a hydraulic line (first actuator line (54)) between the hydraulic pump (hydraulic pump (51)) and the hydraulic cylinder (e.g., boom cylinder (45)), an accumulator (accumulator (58)) that absorbs pressure fluctuations of said hydraulic cylinder (e.g., boom cylinder (45)), a first state that allows the flow of hydraulic fluid from said hydraulic cylinder (e.g., boom cylinder (45)) to said accumulator (accumulator (58)) and allows the flow of hydraulic fluid from said hydraulic cylinder (e.g., boom cylinder (45)) to said tank (tank (57)) to operate a vibration suppression function, and from said hydraulic cylinder (e.g., boom cylinder (45)) said It has a switching valve device (e.g., a first RC valve (59) and a second RC valve (63)) that switches to a second state in which the flow of hydraulic fluid to the accumulator (accumulator (58)) is blocked, and the flow of hydraulic fluid from the hydraulic cylinder (e.g., boom cylinder (45)) to the tank (tank (57)) is blocked, thereby stopping the vibration suppression function.

[0036] The hydraulic system also has a pilot hydraulic circuit that drives each control valve of the control valve unit (53) and releases the function of the HR valve (56). The pilot hydraulic circuit has a pilot pump (71) driven by an engine (35) as a prime mover, an operating device (26) (see FIG. 2) that generates an operating pilot pressure to drive the control valve of the control valve unit (53) and a release pilot pressure used to release the function of the HR valve (56) using the discharge pressure of the pilot pump (71) as the original pressure, an HRV release valve (73) that outputs the discharge pressure of the pilot pump (71) as a release pilot pressure used to release the function of the HR valve (56) without passing through the operating device (26), and a shuttle valve (74) that selects the release pilot pressure of the high-pressure release pilot pressure among the release pilot pressure output from the operating device (26) and the release pilot pressure output from the HRV release valve (73) and outputs it to the HR valve (56).

[0037] The operating device (26) is connected to an input port on one side of the shuttle valve (74) via a first pilot line (75). However, the first pilot line (75) is used only for boom lowering operation. The HRV release valve (73) is connected to an input port on the other side of the pilot pump (71) and the shuttle valve (74) via a second pilot line (76). The output port of the shuttle valve (74) is connected to the hydraulic part (82a) of the pilot valve (82) of the HR valve (56). Additionally, in FIG. 3, a hydraulic circuit indicating the input of the operating pilot pressure from the operating device (26) to the control valve unit (53) is omitted.

[0038] The HRV release valve (73) is configured to selectively switch between a first position N, which blocks the connection between the pilot pump (71) and the shuttle valve (74), and a second position C, which connects the pilot pump (71) and the shuttle valve (74), and is capable of switching to either maintaining or releasing the function of the HR valve (56). The first position N is a position in which the function of the HR valve (56) is maintained (the function is not forcibly released) without outputting the release pilot pressure to the pilot valve (82) (shuttle valve (74)) of the HR valve (56). The second position C is a position in which the function of the HR valve (56) is forcibly released by outputting the release pilot pressure to the pilot valve (82) (shuttle valve (74)) of the HR valve (56). The HRV release valve (73) is an electronic valve configured to be in the first position N, for example, under normal conditions. The HRV release valve (73) is configured to be switched according to a command from the control device (100) described later.

[0039] The HR valve (56) is provided with a first pressure sensor (96) that detects the pressure of the cylinder connection chamber (87). That is, the first pressure sensor (96) detects the pressure of the bottom chamber (Cb) of the boom cylinder (45) (hereinafter referred to as bottom pressure). The first pressure sensor (96) outputs a detection signal according to the detected value to the control device (100) described later.

[0040] A second pressure sensor (97) is provided in the first pilot line (75). The second pressure sensor (97) detects the operation pilot pressure of the control valve unit (53) generated by the operation device (26) and functions as an operation detector that detects an operation instruction from the operation device (26). The second pressure sensor (97) outputs a detection signal according to the detected value to the control device (100) described later.

[0041] A third pressure sensor (98) is provided in the second pilot line (76). The third pressure sensor (98) detects the release pilot pressure output by the HRV release valve (73) and is used as information for determining whether the HRV release valve (73) is faulty. The third pressure sensor (98) outputs a detection signal according to the detected value to the control device (100) described later.

[0042] In the driving system of the hydraulic shovel (1), the driving hydraulic motor (17) is driven by supplying hydraulic fluid from the hydraulic pump (51) through the control valve unit (53). The rotational power of the driving hydraulic motor (17) is transmitted to the front wheels (13) and rear wheels (15) (wheels) through a power transmission mechanism such as a transmission (18) or an axle (12, 14). The transmission (18) transmits the rotational power of the driving hydraulic motor (17) to the front wheels (13) and rear wheels (15) by shifting the speed. A speed sensor (99) is installed in the transmission (18) to detect the rotational speed (number of rotations) of the wheels (13, 15). The driving speed of the hydraulic shovel (1) (vehicle body (2, 3)) is calculated based on the rotational speed (number of rotations) of the wheels (13, 15), which is the detected value of the speed sensor (99). The speed sensor (99) outputs a detection signal according to the detected rotational speed (number of rotations) to the control device (100) described later.

[0043] In the hydraulic shovel (1), the axles (12, 14) are installed to be oscillating relative to the frame (11), and a pair of left and right ram cylinders (66) (only one is shown) are interposed and mounted between the axles (12, 14) and the frame (11). Each ram cylinder (66) has a rod (66a), and functions as a shock absorber to absorb vibrations on the frame (11) side by extending and retracting the rod (66a) in accordance with the oscillation of the axles (12, 14). The hydraulic shovel (1) is equipped with a locking mechanism that prevents the axles (12, 14) from oscillating relative to the frame (11) by locking the extension and retraction of the rod (66a) of the ram cylinders (66).

[0044] Specifically, as a locking mechanism, each ram cylinder (66) is connected to the hydraulic fluid tank (57) through a pilot check valve (67). The pilot check valve (67) is configured to allow the flow of hydraulic fluid from the hydraulic fluid tank (57) to the ram cylinder (66), while blocking the flow of hydraulic fluid from the ram cylinder (66) to the hydraulic fluid tank (57). The pilot port of the pilot check valve (67) is configured to be selectively connected to either the pilot pump (71) or the hydraulic fluid tank (57) through an axle lock valve (78).

[0045] The axle lock valve (78) is configured to selectively switch between a first position L, in which the pilot port of the pilot check valve (67) is connected to the hydraulic fluid tank (57), and a second position C, in which the pilot port of the pilot check valve (67) is connected to the pilot pump (71). The first position L is a lock position that activates the axle lock, which prevents oscillation of the frame (11) of the axle (12, 14). The second position C is a release position that releases the axle lock.

[0046] When the axle lock valve (78) is in the first position L, the pilot check valve (67) functions as a check valve, thereby preventing the leakage of hydraulic fluid from the ram cylinder (66). As a result, the extension and retraction of the ram cylinder (66) becomes impossible, and thus the axle lock becomes activated (locked state), making it impossible for the axle (12, 14) to move. When the axle lock valve (78) is in the second position C, the pilot check valve (67) functions as an open valve, so the ram cylinder (66) and the hydraulic fluid tank (57) are in communication, allowing for bidirectional flow of hydraulic fluid. As a result, the ram cylinder (66) becomes capable of extension and retraction, so the ram cylinder (66) extends and retracts in accordance with the movement of the axle (12, 14), thereby absorbing vibrations on the frame (11) side. That is, the axle lock becomes released (released state). The axle lock valve (78) is an electronic valve configured to be in a first position L in normal conditions, for example. The axle lock valve (78) is configured to be switched according to a command from the control device (100) described later.

[0047] Next, the hardware configuration and functional configuration of the control device in the first embodiment of the wheeled construction machine of the present invention will be explained using FIGS. 4 and 5. FIGS. 4 is a block diagram illustrating the function of the control device in the wheeled construction machine according to the first embodiment shown in FIGS. 1. FIGS. 5 is an explanatory diagram illustrating the load hanging operation when the control device of the wheeled construction machine according to the first embodiment shown in FIGS. 4 performs overload alarm control.

[0048] The control device (100) of the present embodiment is configured to perform axle lock switching control that prevents oscillation of the frame (11) of the axle (12, 14), and to perform overload alarm control that issues an alarm when the load of the load hanging work by the front work device (4) is excessive. In addition, the control device (100) is configured to perform ride control (vibration suppression function) that controls the flow of hydraulic fluid from the boom cylinder (45) to suppress vibration of the boom cylinder (45) when the vehicle body (2, 3) is driven (when the rotational speed of the wheels (13, 15) reaches a predetermined level or higher).

[0049] Specifically, an overload alarm switch (32) and an RC switch (31) are electrically connected to the control device (100). The overload alarm switch (32) is an indicator device that indicates the overload alarm control described above by operation of an operator, and outputs an ON signal indicating an overload alarm control instruction or an OFF signal indicating no overload alarm control instruction to the control device (100). The RC switch (31) is a vibration suppression indicator device that indicates the validity or invalidity of the control of the ride control (vibration suppression function) by the control device (100) according to operation of an operator, and outputs an ON signal indicating the validity of the control of the ride control (vibration suppression function) by the control device (100) or an OFF signal indicating the invalidity of the control of the ride control (vibration suppression function) by the control device (100) to the control device (100).

[0050] In addition, a first pressure sensor (96), a second pressure sensor (97), and a third pressure sensor (98) are electrically connected to the control device (100), and the detection value Pb (boom bottom pressure) of the first pressure sensor (96), the detection value Pp (operation pilot pressure of the operating device (26)) of the second pressure sensor (97), and the detection value Pc (release pilot pressure of the HRV release valve (73)) of the third pressure sensor (98) are input as detection signals. In addition, a speed sensor (99) is electrically connected to the control device (100), and the detection value V (rotational speed of the wheels (13, 15)) of the speed sensor (99) is input as a detection signal. The control device (100) converts the detection value V of the speed sensor (99) into the driving speed Vt of the hydraulic shovel (1) (vehicle body (2, 3)).

[0051] The control device (100) is equipped with a memory device (101) consisting of, for example, RAM or ROM, and a processing device (102) such as a CPU or MPU. In the memory device (101), programs or information necessary for various controls, such as the axle lock switching control, overload alarm control, and ride control described above, are stored in advance. As the memory device (101), it is also possible to have a configuration that includes a magnetic memory device such as a hard disk drive instead of or in addition to semiconductor memory such as ROM and RAM. The processing device (102) appropriately reads various programs or information from the memory device (101) and executes processing according to the said program to realize various functions including the following function unit.

[0052] The control device (100) has an axle lock control unit (111), an overload alarm control unit (112), and a ride control unit (113).

[0053] The axle lock control unit (111) performs axle lock switching control by switching the lock mechanism, which prevents the axle (12, 14) from oscillating, to a locked state or an unlocked state by allowing or blocking the extension of the ram cylinder (66) by switching the axle lock valve (78) shown in FIG. 3. When the axle lock is in a locked state, a command to switch to a first position L (locked position) is output to the axle lock valve (78). On the other hand, when the axle lock is in an unlocked state, a command to switch to a second position C (released position) is output to the axle lock valve (78). The axle lock control unit (111) maintains information on the switching position of the axle lock valve (78) (i.e., information that the lock mechanism is in a locked state or an unlocked state). For example, it is possible to obtain a signal from the axle lock valve (78).

[0054] The overload alarm control unit (112) performs overload alarm control to issue an alarm when the load of the suspended load W is excessively overloaded during the execution of a load hanging operation (crane operation) by the front work device (4) as shown in FIG. 5. Specifically, when an ON signal of the overload alarm switch (32) is input, the actual load of the suspended load W is calculated, and it is determined whether the actual load of the calculated result exceeds the rated load. If the determination result is an excess, an alarm command is output to, for example, a monitor (33) acting as an alarm device.

[0055] The ride control unit (113) controls the first RC valve (59) and the second RC valve (63) as switching valve devices, and controls the HRV release valve (73) to switch the ride control to an operating state or a stopped state.

[0056] When an off signal (an instruction to disable the control of the ride control by the control device (100)) is input from the RC switch (31), the first RC valve (59) and the second RC valve (63) are controlled as switching valve devices so that the ride control is in a stopped state, and the HRV release valve (73) is controlled so that the function of the HR valve (56) is maintained. Specifically, a command (e.g., an off signal) is output to the first RC valve (59) and the second RC valve (63) to switch to a first position S (a position that blocks the flow from the boom cylinder (45) to the accumulator (58) and the hydraulic fluid tank (57). Additionally, a command (e.g., an off signal) is output to the HRV release valve (73) to switch to a first position N (a position that blocks the output of the release pilot pressure to the HR valve (56).

[0057] When a signal is received from the RC switch (31) (an instruction indicating the validity of the control of the ride control by the control device (100)), the ride control unit (113) determines whether to operate the ride control based on the presence or absence of an instruction for overload alarm control from the overload alarm switch (32) (on signal or off signal) and the state of the lock mechanism (locked state or released state of the axle lock). In addition, it determines whether to operate the ride control based on three execution conditions: the detection value of the first pressure sensor (96) (boom bottom pressure Pb), the detection value of the second pressure sensor (97) (operation pilot pressure Pp of the control valve unit (53)), and the detection value of the speed sensor (99) (rotational speed V of the wheels (13, 15)). Based on these determination results, the first RC valve (59), the second RC valve (63), and the HRV release valve (73) are controlled. When switching the ride control to an operating state, a command (e.g., excitation current) is output to the first RC valve (59) and the second RC valve (63) to switch to a second position R (a position that allows bidirectional flow between the bottom seal (Cb) of the boom cylinder (45) and the accumulator (58). Additionally, a command (e.g., excitation current) is output to the HRV release valve (73) to switch to a second position C (a position that outputs the release pilot pressure to the HR valve (56)).

[0058] In addition, if the HRV release valve (73) is malfunctioning, the ride control is stopped. Whether the HRV release valve (73) is malfunctioning is determined by the detection value of the third pressure sensor (98) (release pilot pressure output by the HRV release valve (73)).

[0059] Next, the processing procedure of the ride control unit of the control device in the first embodiment of the wheeled construction machine of the present invention will be explained using FIGS. 6 and 7. FIG. 6 is a flowchart showing an example of the processing procedure of the ride control in the control device of the wheeled construction machine according to the first embodiment shown in FIG. 4. FIG. 7 is a diagram explaining the jack-up operation in the wheeled construction machine according to the first embodiment shown in FIG. 1.

[0060] In FIG. 6, the ride control unit (113) of the control device (100) (see FIG. 4) determines whether the instruction signal from the RC switch (31) is an ON signal (an instruction indicating the validity of the control of the ride control by the control device (100)) (step S10). If the instruction signal from the RC switch (31) is an ON signal (in the case of "Yes"), proceed to step S20, while if the instruction signal from the RC switch (31) is an OFF signal (an instruction indicating the invalidity of the control of the ride control by the control device (100)) (in the case of "No"), proceed to step S90.

[0061] If the result is determined to be "No" in step S10, the ride control unit (113) switches the ride control to a stop state (step S90). Specifically, a command to switch to a first position N (second state) is output to the first RC valve (59) and the second RC valve (63) (switching valve device). As a result, the flow from the bottom seal (Cb) of the boom cylinder (45) to the accumulator (58) is blocked, and the flow from the rod seal (Cr) of the boom cylinder (45) to the hydraulic fluid tank (57) is blocked. Additionally, the HRV release valve (73) is controlled to maintain the function of the HR valve (56). Specifically, a command to switch to a first position N is output to the HRV release valve (73) shown in FIG. 3.

[0062] Meanwhile, if the result is determined to be "Yes" in step S10, it is determined whether the instruction signal from the overload alarm switch (32) is an ON signal (whether there is an instruction for overload alarm control) (step S20). If the instruction signal from the overload alarm switch (32) is an OFF signal (in the case of "No" where there is no instruction for overload alarm control), the process proceeds to step S30, whereas if the instruction signal from the overload alarm switch (32) is an ON signal (in the case of "Yes"), the process proceeds to step S90, which switches the ride control to a stop state.

[0063] If the result is determined as "No" in step S20, the ride control unit (113) determines whether the axle lock (lock mechanism) is in a locked state (step S30). If the axle lock is in a locked state (in the case of "Yes"), the process proceeds to step S90, which switches the ride control to a stopped state, while if the axle lock is in an unlocked state (in the case of "No"), the process proceeds to step S40. The state of the axle lock (lock mechanism) (locked state or unlocked state) is determined, for example, based on the switching position information of the axle lock valve (78) of the axle lock control unit (111). That is, if the switching position information of the axle lock valve (78) is the first position L, the axle lock is determined to be in a locked state. On the other hand, if the switching position information is the second position C, the axle lock is determined to be in an unlocked state.

[0064] If the result is determined as "No" in step S30, the ride control unit (113) determines whether the ride control is in a stopped state (step S40). If the ride control is in a stopped state (in the case of "Yes"), proceed to step S50, while if the ride control is in operation (in the case of "No"), proceed to step S110. The state of the ride control (stopped state or operating state) is determined based on information regarding the switching positions of, for example, the first RC valve (59) and the second RC valve (63). That is, if the information regarding the switching positions of the first RC valve (59) and the second RC valve (63) is the first position S, the ride control is determined to be in a stopped state. On the other hand, if the information regarding the switching positions is the second position R, the ride control is determined to be in an operating state.

[0065] If the result is determined to be "yes" in step S40, the ride control unit (113) determines whether the pressure (boom bottom pressure Pb) of the bottom chamber (Cb) of the boom cylinder (45), which is the detection value of the first pressure sensor (96), satisfies the conditions for the execution of the ride control (step S50). If the boom bottom pressure Pb satisfies the conditions (in the case of "yes"), the process proceeds to step S60, whereas if the conditions for the execution are not satisfy (in the case of "no"), the process proceeds to step S90, which switches the ride control to a stopped state.

[0066] Specifically, when the boom bottom pressure Pb, which is the detected value of the first pressure sensor (96), is greater than the first threshold P1 and also less than the second threshold P2 (P1 <Pb<P2인 경우)에는, 라이드 컨트롤의 제1 실행 조건을 충족하고 있다("예")고 판정한다. 그 이외의 경우에는, 라이드 컨트롤의 제1 실행 조건을 충족하고 있지 않다("아니오")고 판정한다. 제1 역치 P1은, 예를 들어 프론트 작업 장치(4)를 공중에 유지하기 위해 필요한 붐 보텀압의 하한값이다. 제2 역치 P2는, 예를 들어 라이드 컨트롤 릴리프 밸브(61)의 설정압 이하로 설정되어 있다.

[0067] The condition Pb > P1 is a determination condition for whether the hydraulic shovel (1) is in a jack-up operation. A jack-up operation is an operation to lift the vehicle body (2) and the slewing body (3) by bringing the bucket (43) (attachment) or the excavation blade (5) of the front work device (4) to the ground, as shown in FIG. 7, for example. During a jack-up operation, the pressure of the rod seal (Cr) of the boom cylinder (45) becomes high, while the pressure of the bottom seal (Cb) (boom bottom pressure (Pb)) becomes low. From this, if the boom bottom pressure Pb is less than or equal to the first threshold P1, it is determined that there is a possibility that the jack-up operation is in progress and that the first execution condition of the ride control is not satisfied.

[0068] Pb <P2의 조건은, 라이드 컨트롤이 실행되었을 때에 붐(41)의 침하를 방지하기 위한 판정 조건이다. 붐 실린더(45)의 보텀실(Cb)로부터 어큐뮬레이터(58)에 유입된 압유가 고압인 경우, 라이드 컨트롤 릴리프(62)가 밸브 개방되는 경우가 있다. 이 경우, 붐 실린더(45)의 보텀실(Cb)이 작동유 탱크(57)에 연통되므로, 붐 실린더(45)의 피스톤 로드(45c)가 단축되어 붐(41)이 침하해 버린다. 따라서, 붐 보텀압 Pb가 제2 역치 P2를 초과하는 경우에는, 라이드 컨트롤 릴리프(62)의 밸브 개방에 의한 붐(41)의 침하의 가능성이 있어, 라이드 컨트롤의 제1 실행 조건을 충족하고 있지 않다고 판정한다.

[0069] If the result is determined to be "Yes" in step S50, the ride control unit (113) determines whether the driving speed Vt of the hydraulic shovel (1) satisfies the second execution condition of the ride control (step S60). The second execution condition is a determination condition regarding the necessity of suppressing vibrations caused by the driving of the hydraulic shovel (1). If the driving speed Vt satisfies the second execution condition (in the case of "Yes"), the process proceeds to step S70, whereas if the driving speed Vt does not satisfies the second execution condition (in the case of "No"), the process proceeds to step S90, which switches the ride control to a stopped state.

[0070] Specifically, when the driving speed Vt of the hydraulic shovel (1) obtained by converting the detection value of the speed sensor (99) (rotational speed V of the wheels (13, 15)) is greater than or equal to the first threshold V1 (when Vt ≥ V1), it is determined that the second execution condition of the ride control is satisfied ("Yes"). Otherwise, it is determined that the second execution condition is not satisfied ("No"). The first threshold V1 is a setting value that can be input by, for example, an operator from an input device (e.g., a monitor (33) having a touch panel, etc.). As the first threshold V1, a setting of, for example, 4 to 10 km / h is assumed.

[0071] If the result is determined to be "Yes" in step S60, the ride control unit (113) determines whether the third execution condition of the ride control is satisfied based on whether there is operation of the front work device (4) in the operating device (26) (step S70). The third execution condition is a determination condition to prevent hydraulic fluid from the hydraulic pump (51) from flowing into the hydraulic circuit of the ride control when the ride control is operated by the operation of the front work device (4). If there is no operation of the front work device (4) in the operating device (26) (in the case of "Yes"), proceed to step S80 to switch the ride control to an operating state, while if there is operation of the front work device (4) in the operating device (26) (in the case of "No"), proceed to step S90 to stop the ride control.

[0072] Specifically, when the operation pilot pressure Pp output by the operation device (26), which is the detection value of the second pressure sensor (97), is less than or equal to the third threshold P3 (when Pp ≤ P3), it is determined that there is no operation on the front work device (4) and the third execution condition of the ride control is satisfied ("Yes"). In other cases, it is determined that there is an operation on the work device (4) and the third execution condition is not satisfied ("No"). The third threshold P3 is, for example, the operation pilot pressure at which each control valve of the control valve unit (53) is not driven.

[0073] If the result is determined as "Yes" in step S70, the ride control unit (113) switches the ride control to an operating state (step S80). Specifically, it outputs a command to switch to the second position R (first state) for the first RC valve (59) and the second RC valve (63) (switching valve device). In addition, it controls the HRV release valve (73) so that the function of the HR valve (56) is released. That is, it outputs a command to switch to the second position C for the HRV release valve (73). By doing so, the function of the HR valve (56) is forcibly released (the HR valve (56) is opened), allowing bidirectional flow between the bottom seal (Cb) of the boom cylinder (45) and the accumulator (58). In addition, bidirectional flow between the rod seal (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57) is allowed.

[0074] Meanwhile, if it is determined to be "No" in step S40, that is, if it is determined that the ride control is running, the ride control unit (113) determines whether the driving speed Vt of the hydraulic shovel (1) satisfies the stop condition of the ride control (step S110). If the driving speed Vt satisfies the stop condition (in the case of "Yes"), proceed to step S90, which switches the ride control to a stop state, while if the driving speed Vt does not satisfies the stop condition (in the case of "No"), proceed to step S120.

[0075] Specifically, when the driving speed Vt obtained by converting the detection value of the speed sensor (99) (rotational speed V of the wheels (13, 15)) is less than or equal to the second threshold V2 (when V ≤ V2), it is determined that the stopping condition of the ride control is satisfied ("Yes"). Otherwise, it is determined that the stopping condition is not satisfied ("No"). The second threshold V2 is, for example, a setting value of a lower speed than the first threshold V1, which is the execution condition of the ride control. For example, a setting of 2 km / h is assumed for the second threshold V2.

[0076] If the result is determined as "No" in step S110, the ride control unit (113) determines whether the stop condition of the ride control is satisfied based on whether there is operation of the front work device (4) in the operating device (26) (step S120). This stop condition is a determination condition to prevent hydraulic fluid from the hydraulic pump (51) from flowing into the hydraulic circuit of the ride control by operation of the front work device (4) during the operation of the ride control, just like the second execution condition of the ride control. If there is operation of the front work device (4) in the operating device (26) (in the case of "Yes"), proceed to step S90 to switch the ride control to a stop state, while if there is no operation of the front work device (4) in the operating device (26) (in the case of "No"), proceed to step S80 to switch the ride control to an operating state.

[0077] Specifically, when the operation pilot pressure Pp output by the operation device (26), which is the detection value of the second pressure sensor (97), is greater than or equal to the fourth threshold P4 (when Pp ≥ P4), it is determined that there is operation on the front work device (4) and the stop condition of the ride control is satisfied ("Yes"). In other cases, it is determined that there is no operation on the work device (4) and the stop condition is not satisfied ("No"). The fourth threshold P4 is a set value higher than the third threshold P3 of the third execution condition of the ride control.

[0078] The control of switching to a stop state of the ride control when determined as "yes" in step S120 (step S80) and the control of the operating state of the ride control when determined as "no" in step S120 (step S90) are the same as the control for the first RC valve (59), the second RC valve (63), and the HRV release valve (73) described above.

[0079] In this way, the hydraulic shovel (1) is configured to switch the operation and stop of the ride control function according to various situations, even when the ride control is effective, by using the detection value of the pressure of a hydraulic cylinder, such as a boom cylinder (45), the operation pilot pressure (operation pilot pressure Pp), the detection value of a speed sensor, etc. For example, when the control device (100) indicates that the control of the vibration suppression function is effective from the vibration suppression indicator device (RC switch (31)), it controls the switching valve device (first RC valve (59) and second RC valve (63)) to a first state (second position R) or a second state (first position S) based on the detection value of the pressure of the hydraulic cylinder by the pressure sensor, the detection value of the operation detector, and the detection value of the speed sensor.

[0080] For example, in the present embodiment, when the instruction signal from the RC switch (31) indicates that the control device (100) is an instruction for the effective control of the ride control by the control device (100), the control device (100) switches the ride control to either an operating state or a stopped state by determining whether all three execution conditions of the ride control are satisfied based on the detection value of the first pressure sensor (96) (boom bottom pressure Pb), the detection value of the second pressure sensor (97) (operation pilot pressure Pp of the operating device (26)), and the detection value of the speed sensor (99) (rotational speed V of the wheels (13, 15). In addition, the control device switches the ride control to either an operating state or a stopped state based on the presence or absence of an instruction signal from the overload alarm switch (32) and the state of the axle lock (lock mechanism such as the axle lock valve (78)) (locked state or released state). In addition, when the ride control is in operation, the ride control is switched to either an operating state or a stopped state by determining whether one of the two stopping conditions of the ride control is satisfied.

[0081] Next, the operation of the hydraulic system in the first embodiment of the wheeled construction machine of the present invention will be described. First, the operation of the hydraulic system during the operation of the front working device (boom) when the RC switch of the hydraulic shovel indicates ineffective will be described using FIGS. 3 and 5.

[0082] When a boom raising operation is performed on the operating device (26) shown in FIG. 3, the corresponding control valve of the control valve unit (53) is driven by the operating pilot pressure (boom raising command) generated by the operating device (26). As a result, the hydraulic fluid of the hydraulic pump (51) is supplied to the pipe connection chamber (86) of the HR valve (56) through the first actuator line (54). As a result, the poppet valve (81) of the HR valve (56) is opened, so the hydraulic fluid from the hydraulic pump (51) is supplied from the pipe connection chamber (86) of the HR valve (56) through the cylinder connection chamber (87) to the bottom chamber (Cb) of the boom cylinder (45). At this time, the hydraulic fluid of the rod chamber (Cr) of the boom cylinder (45) is discharged to the hydraulic fluid tank (57) through the second actuator line (55) and the control valve unit (53). By doing so, the boom cylinder (45) is extended and the boom is raised.

[0083] When a boom lowering operation is performed on the operating device (26), the corresponding control valve of the control valve unit (53) is driven by the operating pilot pressure (boom lowering command) of the operating device (26). As a result, the hydraulic fluid of the hydraulic pump (51) is supplied to the rod seal (Cr) of the boom cylinder (45) through the second actuator line (55). At this time, the operating pilot pressure (boom lowering command) of the operating device (26) is input as a release pilot pressure to the hydraulic part (82a) of the pilot valve (82) of the HR valve (56) through the shuttle valve (74). Also, since ride control is not executed due to the invalid instruction from the RC switch (31), the release pilot pressure of the HRV release valve (73) is not output from the shuttle valve (74). In the HR valve (56), the pilot valve (82) is displaced by the input of the release pilot pressure of the operating device (26), thereby connecting the pipe connection chamber (86) and the back pressure chamber (88) and opening the poppet valve (81). As a result, the hydraulic fluid in the bottom chamber (Cb) of the boom cylinder (45) is discharged from the HR valve (56) to the hydraulic fluid tank (57) through the first actuator line (54) and the control valve unit (53). As a result, the boom cylinder (45) is shortened, and a boom lowering operation is performed.

[0084] If the first actuator line (54) is broken during boom lifting operation, the pressure in the pipe connection chamber (86) of the HR valve (56) is reduced to atmospheric pressure. Meanwhile, in the back pressure chamber (88), the high load pressure of the bottom chamber (Cb) of the boom cylinder (45) is induced through the throttle connection passage (85a). Because of this, the poppet valve (81) is immediately closed, so the leakage of pressurized oil from the bottom chamber (Cb) of the boom cylinder (45) to the first actuator line (54) is prevented, and the falling of the boom (41) is prevented.

[0085] In addition, when performing a load hanging operation by the front work device (4) as shown in FIG. 5, the axle lock is locked. That is, the control device (100) (see FIG. 4) maintains the axle lock valve (78) in the first position L (lock position) by outputting an off signal to the axle lock valve (78). As a result, the pilot check valve (67) functions as a check valve, so the extension and retraction of the ram cylinder (66) is prevented, and the oscillation of the axles (12, 14) is restricted. This prevents the slewing body (3) from becoming unstable during the load hanging operation.

[0086] Next, the operation of the hydraulic system when the RC switch of the hydraulic shovel is in a valid state will be explained using FIGS. 3 to 7. It is assumed that the hydraulic shovel begins to move from the work site and travels on a public road.

[0087] The operator of the hydraulic shovel (1) switches the RC switch (31) shown in FIG. 4 to ON (effective). When the instruction from the RC switch (31) is effective, the control device (100) determines whether the overload alarm switch (32) is ON (step S20 shown in FIG. 6) and determines whether the axle lock is in a locked state (step S30 shown in FIG. 6).

[0088] In the case of driving with a load as illustrated in FIG. 5, the overload alarm switch (32) is operated to ON, and the axle lock is in a locked state. Therefore, in the case of driving with a load, the control device (100) illustrated in FIG. 4 determines "Yes" in step S20 or S30 shown in FIG. 6, and stops the ride control even if the instruction from the RC switch (31) indicates that the control of the ride control by the control device (100) is valid (step S90). That is, the control device (100) outputs an off signal to the first RC valve (59) and the second RC valve (63), and outputs an off signal to the HRV release valve (73).

[0089] Accordingly, the first RC valve (59) and the second RC valve (63) shown in FIG. 3 are maintained in the first position S (second state), and the HRV release valve (73) is maintained in the first position N (unreleased position). Thus, the flow from the bottom seal (Cb) of the boom cylinder (45) to the accumulator (58) through the HR valve (56) is blocked, and the flow from the load seal (Cr) of the boom cylinder (45) to the hydraulic fluid tank (57) is blocked. In addition, the function of the HR valve (56) is maintained without being released. Because of this, even if the first actuator line (54) is broken while driving with a load, the HR valve (56) functions as described above to prevent the leakage of hydraulic fluid from the bottom seal (Cb) of the boom cylinder (45), thereby preventing the boom (41) from falling while driving.

[0090] In this way, in the present embodiment, whether the hydraulic shovel (1) is carrying a load is determined based on the indication of the overload alarm switch (32) and the state of the axle lock, and if it is carrying a load, the ride control is stopped even if the indication of the RC switch (31) is valid. By doing so, it is possible to prevent the vehicle body (turning body (3)) from becoming unstable due to the execution of the ride control when carrying a load. In addition, since there is no need to operate the RC switch (31) to indicate the invalidation of the ride control so that the ride control is not executed when carrying a load, the operator's operation of the RC switch (31) can be reduced.

[0091] Meanwhile, during normal driving other than driving with a load, the control device (100) determines whether all three execution conditions of the ride control are satisfied (steps S50 to S70 shown in FIG. 6). During normal driving, since the front work device (4) is not in contact with the ground and is maintained in the air, the boom bottom pressure Pb is higher than the first threshold P1. Therefore, the control device (100) determines that the first execution condition of the boom bottom pressure Pb is satisfied ("Yes" in step S50 shown in FIG. 6). When the hydraulic shovel (1) reaches a driving state at a speed higher than the first threshold speed V1, it determines that the second execution condition of the driving speed Vt is satisfied ("Yes" in step S60 shown in FIG. 6).

[0092] When the operating device (26) is operated while driving, the third execution condition of the operating pilot pressure Pp is not satisfied (determined as “No” in step S70 shown in FIG. 6), and even if the instruction of the RC switch (31) is valid, a command to stop the ride control is output (step S90 shown in FIG. 6). By doing so, high-pressure hydraulic fluid from the hydraulic pump (51) is prevented from flowing into the hydraulic circuit regarding the ride control (such as the hydraulic circuit connecting the bottom seal (Cb) of the boom cylinder (45) and the accumulator (58).

[0093] Meanwhile, when the hydraulic shovel (1) is driven while the front work device (4) is in a stationary state, it is determined that the third execution condition of the operation pilot pressure Pp is satisfied (in step S70 shown in FIG. 6, "Yes"), and a command to operate the ride control is output according to the effective instruction of the RC switch (31) (in step S80 shown in FIG. 6). That is, the control device (100) outputs an ON signal to the HRV release valve (73) shown in FIG. 3, and at the same time outputs an ON signal to the first RC valve (59) and the second RC valve (63). By doing so, the HR valve (56) is opened, allowing bidirectional flow between the bottom seal (Cb) of the boom cylinder (45) and the accumulator (58), and also allowing bidirectional flow between the rod seal (Cr) of the boom cylinder (45) and the hydraulic fluid tank (57). Therefore, even if the front work device (4) vibrates during driving, the accumulator (58) absorbs the vibration energy, so the pitching or bouncing of the swivel body (3) caused by the movement of the front work device (4) can be reduced.

[0094] When the ride control is operated in this manner, the control device (100) determines whether the stop condition of the ride control is satisfied (S110 and S120 from the "No" determination of step S40 shown in FIG. 6). When the ride control is in operation and the front work device (4) is operated, it is determined that the stop condition of the operation pilot pressure Pp is satisfied ("Yes" in step S120 shown in FIG. 6) and the ride control is switched to a stop state. In addition, when the driving speed Vt of the hydraulic shovel (1) is lowered to a second threshold speed V2 or lower, it is determined that the stop condition of the driving speed Vt is satisfied ("Yes" in step S110 shown in FIG. 6) and a command to stop the ride control is output.

[0095] Additionally, when moving from the work site to the public road, there are cases where mud attached to the wheels is removed before moving to the public road. For example, the operator temporarily stops the hydraulic shovel (1) that was being driven while the RC switch (31) was turned on. Due to the cessation of driving, the ride control is in a stopped state. Then, the jack-up operation shown in FIG. 7 is performed, and the wheels (13, 15) are rotated in the jack-up state. In this case, since the bucket (43) of the front work device (4) is in contact with the ground due to the jack-up operation, the boom bottom pressure Pb is lower than the first threshold P1.

[0096] At this time, since the RC switch (31) is ON (indicating validity) and the ride control is in a stopped state, the control device (100) determines whether the three execution conditions of the ride control are satisfied (steps S50 to S70 shown in FIG. 6). Even if the driving speed Vt, which is converted from the speed V of the idle wheels (13, 15), is greater than or equal to the first threshold V1 and there is no operation of the front work device (4), the boom bottom pressure Pb is lower than the first threshold P1, so the first execution condition of the boom bottom pressure Pb is not satisfied (determined as "No" in step S50 shown in FIG. 6). Accordingly, the control device (100) maintains the ride control in a stopped state.

[0097] If the ride control is activated by rotating the wheels (13, 15) during the jack-up operation, the hydraulic fluid in the rod seal (Cr) of the boom cylinder (45) leaks out through the second RC valve (63) into the hydraulic fluid tank (57) due to the load of the jack-up, making it impossible to maintain the jack-up. Therefore, in this embodiment, considering that the boom bottom pressure Pb is lower during the jack-up than during driving, the boom bottom pressure Pb is used as one of the conditions for executing the ride control. As a result, even if the RC switch (31) remains ON (indicated as effective), the ride control is not activated during the jack-up. Therefore, when rotating the wheels (13, 15) in the jack-up state, there is no need to perform a switching operation of the RC switch (31) from ON (effective) to OFF (ineffective) to prevent the ride control from operating. In other words, the control device (100) disables the control of the vibration suppression function even when the vibration suppression function is indicated to be effective by the vibration suppression indicator device (RC switch (31)) when the vehicle body (2, 3) is jacked up by the front work device (4).

[0098] As described above, the wheel-type hydraulic shovel (1) (wheel-type construction machine) according to the first embodiment comprises a self-propelled vehicle body (2, 3) on which wheels (13, 15) are installed, a front work device (4) (work device) installed on the vehicle body (2, 3), a control device (100) that controls the flow of hydraulic fluid from a hydraulic cylinder (boom cylinder (45), arm cylinder (46), bucket cylinder (47)) that drives the front work device (4) (work device) to suppress vibration of the hydraulic cylinder (boom cylinder (45), arm cylinder (46), bucket cylinder (47)) when the rotational speed of the wheels (13, 15) reaches a predetermined level or higher, and an RC switch (31) as a vibration suppression indicator device that indicates the effectiveness or invalidity of the control of the vibration suppression function by the control device (100). The control device (100) disables the control of the vibration suppression function even when the RC switch (31) (vibration suppression indicator device) indicates that the control of the vibration suppression function is effective when the vehicle body (2, 3) is jacked up by the front work device (4) (work device).

[0099] According to this configuration, even when the RC switch (31) (vibration suppression indicator) indicates that the control of the vibration suppression function is effective, when the vehicle body (2, 3) is jacked up by the front work device (4) (work device), the control of the vibration suppression function is disabled, so the operator does not need to perform an operation to indicate the RC switch (31) (vibration suppression indicator) that the control of the vibration suppression function is disabled. In other words, the inconvenience of operating the RC switch (31) (vibration suppression indicator) can be reduced.

[0100] Additionally, the wheeled hydraulic shovel (1) (wheeled construction machine) according to the present embodiment comprises a hydraulic pump (51) that supplies hydraulic fluid to hydraulic cylinders (boom cylinder (45), arm cylinder (46), bucket cylinder (47)), a hydraulic line (first actuator line (54)) between the hydraulic pump (51) and the hydraulic cylinder (boom cylinder (45)) and an accumulator (58) that absorbs pressure fluctuations of the hydraulic cylinder (boom cylinder (45)), a first state that allows the flow of hydraulic fluid from the hydraulic cylinder (boom cylinder (45)) to the accumulator (58) and simultaneously allows the flow of hydraulic fluid from the hydraulic cylinder (boom cylinder (45)) to the hydraulic fluid tank (57) (tank) to activate a vibration suppression function, and a first state that blocks the flow of hydraulic fluid from the hydraulic cylinder (boom cylinder (45)) to the accumulator (58) and simultaneously allows the flow of hydraulic fluid from the hydraulic cylinder (boom cylinder (45)) to the hydraulic fluid tank (57) (tank). It is equipped with a first RC valve (59) and a second RC valve (63) as a switching valve device that switches to a second state by blocking the flow of hydraulic fluid to stop the vibration suppression function, an operating device (26) that outputs an operating instruction of a front working device (4) (working device), a first pressure sensor (96) that detects the pressure of a boom cylinder (45) (hydraulic cylinder), a second pressure sensor (97) as an operating detector that detects an operating instruction from the operating device (26), and a speed sensor (99) that detects the rotational speed of the wheels (13, 15). When the control device (100) indicates that the control of the vibration suppression function is effective from the RC switch (31) (vibration suppression indicator device), it is configured to control the first RC valve (59) and the second RC valve (63) (switching valve device) to a second position R (first state) or a first position S (second state) based on the detection value Pb of the first pressure sensor (96), the detection value Pp of the second pressure sensor (97) (operation detector), and the detection value V of the speed sensor (99).

[0101] According to this configuration, as a condition for executing the vibration suppression function by the accumulator (58), in addition to the detection value Pp of the second pressure sensor (97) (operation detector) and the detection value V of the speed sensor (99), the pressure value (boom bottom pressure Pb) of the boom cylinder (45) (hydraulic cylinder) detected by the first pressure sensor (96) is used, so the ability to switch to the operating state of the vibration suppression function can be determined depending on whether or not a jack-up is performed using the front work device (4) (work device). Therefore, when a jack-up is performed when the RC switch (31) (vibration suppression indicator device) is operated and the indication is valid, the operation to switch the RC switch (31) (vibration suppression indicator device) to an invalid indication can be made unnecessary to avoid switching to the operating state of the vibration suppression function. In other words, the inconvenience of operating the RC switch (31) (vibration suppression indicator device) can be reduced.

[0102] In addition, in this embodiment, the working device includes a boom (41), an arm (42), and a bucket (43). The hydraulic cylinder is a boom cylinder (45) that moves the boom (41) upward by supplying hydraulic fluid to the bottom seal (Cb) and moves the boom (41) downward by supplying hydraulic fluid to the rod seal (Cr). The first pressure sensor (96) detects the pressure of the bottom seal (Cb) of the boom cylinder (45). The control device (100) is configured to control the first RC valve (59) and the second RC valve (63) (switching valve device) to a second position R (first state) or a first position S (second state) when the detection value (boom bottom pressure Pb) of the first pressure sensor (96) is lower than a preset first threshold P1 when the effective control of the vibration suppression function is indicated by the RC switch (31) (vibration suppression indicator device).

[0103] According to this configuration, when the hydraulic shovel (1) is in a jack-up state, the vibration suppression function can be reliably stopped.

[0104] In addition, the control device (100) of the present embodiment is configured to control the first RC valve (59) and the second RC valve (63) (switching valve device) based on the detection value V of the speed sensor (99) and the detection value Pp of the second pressure sensor (97) (operation detector), regardless of the detection value (boom bottom pressure Pb) of the first pressure sensor (96) when controlling the first RC valve (59) and the second RC valve (63) (switching valve device) so that the vibration suppression function is in an operating state.

[0105] According to this configuration, even if the boom bottom pressure Pb decreases while the vibration suppression function is in operation, it is possible to avoid unnecessarily stopping the vibration suppression function. When the front working device (4) vibrates in an upward direction while the vibration suppression function is in operation, the boom bottom pressure Pb is temporarily lowered, and then hydraulic fluid flows into the bottom seal (Cb) of the boom cylinder (45). Because of this, there are cases where the boom bottom pressure Pb becomes lower than the first threshold P1. If the vibration suppression function is stopped at this time, the vibration suppression function cannot be effectively exerted. Therefore, the transition to a stopped state of such vibration suppression function is prevented.

[0106] Additionally, the wheel-type hydraulic shovel (1) (wheel-type construction machine) of the present embodiment is equipped with an axle (12, 14) that can oscillate relative to the vehicle body (2, 3) while rotatably supporting the wheel (13, 15), and a lock mechanism (67, 78) that prevents the axle (12, 14) from oscillating. The lock mechanism (67, 78) is controlled to switch to either a locked state or an unlocked state. Additionally, when the control device (100) indicates that the control of the vibration suppression function is effective from the RC switch (31) (vibration suppression indicator device), it controls the first RC valve (59) and the second RC valve (63) (switching valve device) to a second position R (first state) or a first position S (second state) based on the state of the lock mechanism (67, 78) in addition to the detection value Pb of the first pressure sensor (96), the detection value Pp of the second pressure sensor (97) (operation detector).

[0107] According to this configuration, when the lock mechanism (67, 78) that operates when carrying a load is in a locked state, the vibration suppression function is stopped, thereby preventing instability of the turning body (3) (vehicle body) caused by the operation of the vibration suppression function when carrying a load. In other words, to prevent instability of the turning body (3) (vehicle body) caused by the operation of the vibration suppression function when carrying a load, there is no need to perform an operation to switch the indication of the RC switch (31) (vibration suppression indicator device) from effective to ineffective. That is, the inconvenience of operating the RC switch (31) (vibration suppression indicator device) can be reduced.

[0108] In addition, the wheeled hydraulic shovel (1) (wheeled construction machine) of the present embodiment is equipped with an overload alarm switch (32) as an overload alarm indicator device that instructs an overload alarm control that emits an alarm when the load of the load hanging work by the front work device (4) (work device) is excessive. In addition, when the control device (100) indicates that the control of the vibration suppression function is effective from the RC switch (31) (vibration suppression indicator device), the first RC valve (59) and the second RC valve (63) (switching valve device) are controlled to a second position R (first state) or a first position S (second state) based on the presence or absence of an overload alarm control instruction from the overload alarm switch (32) (overload alarm indicator device), in addition to the detection value Pb of the first pressure sensor (96), the detection value Pp of the second pressure sensor (97) (operation detector), and the detection value V of the speed sensor (99).

[0109] According to this configuration, when there is an indication from the overload warning switch (32) (overload warning indicator device) operated while driving with a load, the vibration suppression function is stopped, thereby preventing instability of the turning body (3) (vehicle body) caused by the operation of the vibration suppression function while driving with a load. In other words, to prevent instability of the turning body (3) (vehicle body) caused by the operation of the vibration suppression function while driving with a load, there is no need to perform an operation to switch the indication of the RC switch (31) (vibration suppression indicator device) from effective to ineffective. That is, the inconvenience of operating the RC switch (31) (vibration suppression indicator device) can be reduced.

[0110] Additionally, the wheeled hydraulic shovel (1) (wheeled construction machine) of the present embodiment is installed on a first actuator line (54) (hydraulic line) and is equipped with a hose rupture valve (56) having the function of preventing the leakage of hydraulic fluid from the boom cylinder (45) (hydraulic cylinder) to the first actuator line (54) (hydraulic line) when the first actuator line (54) (hydraulic line) is broken, and an HRV release valve (73) (release valve) capable of switching between maintaining or releasing the function of the hose rupture valve (56). An accumulator (58) is connected to the boom cylinder (45) (hydraulic cylinder) through the hose rupture valve (56). Additionally, the control device (100) is configured to control the HRV release valve (73) (release valve) in addition to the first RC valve (59) and the second RC valve (63) (switching valve device), and when the first RC valve (59) and the second RC valve (63) (switching valve device) are controlled to the second position R (first state), the HRV release valve (73) (release valve) is controlled so that the function of the hose rupture valve (56) is released, and when the first RC valve (59) and the second RC valve (63) (switching valve device) are controlled to the first position S (second state), the HRV release valve (73) (release valve) is controlled so that the function of the hose rupture valve (56) is maintained.

[0111] According to this configuration, even if a hose rupture valve (56) is installed on a boom cylinder (45) (hydraulic cylinder) on which the self-weight of the front work device (4) acts, the vibration suppression function can be activated by releasing the function of the hose rupture valve (56) by the HRV release valve (73) (release valve).

[0112] [Second Embodiment]

[0113] Next, a second embodiment of the wheeled construction machine of the present invention will be described using FIG. 8. FIG. 8 is a circuit diagram illustrating the schematic configuration of a hydraulic system and a block diagram illustrating the schematic configuration of a driving system in a wheeled construction machine according to the second embodiment of the present invention. In FIG. 8, parts with the same symbols as those shown in FIG. 1 to FIG. 7 are the same parts, so their detailed description is omitted.

[0114] The main differences between the second embodiment of the wheeled construction machine of the present invention illustrated in FIG. 8 and the first embodiment are the following three points. First, the accumulator (58A) is connected to the bottom seal (Cb) of the boom cylinder (45) through the first RC valve (59) without passing through the HR valve (56). Second, the ride control relief valve (61) in the first embodiment is omitted (see FIG. 3). Third, the HRV release valve (73) in the first embodiment is omitted (see FIG. 3).

[0115] In detail, the bottom seal (Cb) of the boom cylinder (45) and the cylinder connection seal (87) of the HR valve (56) are connected via the third connection line (69). The accumulator (58A) is connected to the third connection line (69) via the first connection line (60A). That is, the accumulator (58A) is connected to the bottom seal (Cb) of the boom cylinder (45) without passing through the HR valve (56). Because of this, without disabling the function of the HR valve (56), the accumulator (58A) and the bottom seal (Cb) of the boom cylinder (45) become connected by switching only the first RC valve (59), making it possible to operate the ride control. In addition, by increasing the internal pressure of the accumulator (58A), the ride control relief valve (61) in the first embodiment becomes unnecessary.

[0116] In this embodiment, there is no need to disable the function of the HR valve (56) in order to operate the ride control. Therefore, the configuration for disabling the function of the HR valve (56) during the execution of the ride control in the first embodiment is unnecessary. That is, the HRV release valve (73), shuttle valve (74), second pilot line (76), and third pressure sensor (98) in the first embodiment are removed.

[0117] The control device (100) according to the present embodiment is configured to perform ride control that suppresses vibration during driving (when the rotational speed of the wheels (13, 15) reaches a predetermined level) by controlling only the first RC valve (59) and the second RC valve (63) through the accumulator (58A). That is, the control device according to the present embodiment is configured such that, in the control device (100) according to the first embodiment shown in FIG. 4, the input of the detection value of the third pressure sensor (98) is deleted, and the output of the command to the HRV release valve (73) is deleted. That is, the control device according to the present embodiment differs only in the processing method of the operating state or stop state of the ride control in steps S80 and S90 of the processing sequence of the ride control unit (113) shown in FIG. 6. The determination of the execution condition and the determination of the stop condition of the ride control in steps S10 to S70 are completely identical.

[0118] According to the second embodiment of the wheeled construction machine of the present invention described above, even when the control of the vibration suppression function is indicated as effective by the RC switch (31) (vibration suppression indicator device) as in the first embodiment described above, the control of the vibration suppression function is disabled when the vehicle body (2, 3) is jacked up by the front work device (4) (work device), so the operator does not need to perform an operation to indicate the disablement of the control of the vibration suppression function to the RC switch (31) (vibration suppression indicator device). In other words, the inconvenience of operating the RC switch (31) (vibration suppression indicator device) can be reduced.

[0119] [Other embodiments]

[0120] Furthermore, the present invention is not limited to the embodiments described above and includes various modifications. The embodiments described above are detailed to facilitate understanding of the present invention and are not limited to having all the described configurations. For example, it is possible to substitute a part of the configuration of one embodiment with a part of another embodiment, and it is also possible to add a part of another embodiment to a part of one embodiment. Additionally, it is possible to add, delete, or substitute other configurations for a part of the configuration of each embodiment.

[0121] For example, in the above-described embodiment, a wheeled hydraulic shovel (1) was used as an example of a wheeled construction machine, but it can be widely applied to wheeled construction machines equipped with a work device such as a wheel loader.

[0122] In addition, in the above-described embodiment, an example of a configuration was shown in which at least one of the axles (12, 14) is installed on the frame (11) so as to be oscillating, and a lock mechanism (66, 67, 78) that prevents the oscillation of the axles (12, 14) is provided. However, it is also possible to configure both sides of the axles (12, 14) to be fixed to the frame (11). In this case, in the processing sequence of the ride control unit (113) of the control device (100) shown in FIG. 6, the determination of step S30 regarding the axle lock is omitted.

[0123] In addition, in the above-described embodiment, an example of a configuration was shown in which an operating device (26) that outputs an operating instruction of a front working device (4) generates an operating pilot pressure of a control valve unit (53) and simultaneously generates a release pilot pressure of an HR valve (56). However, it is possible to configure the operating device as an electric type, and an electronic proportional valve that uses the discharge pressure of a pilot pump (71) as the source pressure to generate an operating pilot pressure of a control valve unit (53) and simultaneously generates a release pilot pressure of an HR valve (56). In this case, the control device generates the operating pilot pressure and the release pilot pressure by controlling the electronic proportional valve according to the operating signal of the electric operating device. At this time, it is possible to configure the operating device itself, which outputs the operating signal to the control device (100), as the operating detector that detects the operating instruction from the operating device.

[0124] In addition, in the above-described embodiment, an example was shown in which the control device (100) performing ride control is configured to perform axle lock switching control. However, it is also possible for the control device performing axle lock switching control and the control device (100) performing ride control to have different configurations. Explanation of the symbols

[0125] 1: Wheel-type hydraulic shovel (wheel-type construction machine), 2: Vehicle body (chassis), 3: Slewing body (chassis), 4: Front working device (working device), 12, 14: Axle, 13: Front wheel (wheel), 15: Rear wheel (wheel), 26: Operating device, 31: Ride control switch (vibration suppression indicator), 32: Overload alarm switch (overload alarm indicator), 43: Boom, 44: Arm, 45: Bucket, 45: Boom cylinder (hydraulic cylinder), Cb: Bottom seal, Cr: Rod seal, 51: Hydraulic pump, 54: First actuator line (hydraulic line), 56: Hose rupture valve, 57: Hydraulic fluid tank (tank), 58, 58A: Accumulator, 59: First ride control valve (switching valve device), 63: Second ride control valve (switching valve Device), 66: Ram cylinder (locking mechanism), 67: Pilot check valve (locking mechanism), 73: Hose rupture valve release valve (release valve), 78: Axle lock valve (locking mechanism), 96: First pressure sensor (pressure sensor), 97: Second pressure sensor (operation detector). 99: Speed ​​sensor, 100: Control device

Claims

Claim 1 A wheeled construction machine comprising: a self-propelled vehicle body equipped with wheels; a work device installed on the vehicle body; a control device that controls the flow of hydraulic fluid from a hydraulic cylinder driving the work device to suppress vibration of the hydraulic cylinder when the rotational speed of the wheels reaches a predetermined level or higher, and a vibration suppression indicator device that indicates the validity or invalidity of the control of the vibration suppression function by the control device; a hydraulic pump that supplies hydraulic fluid to the hydraulic cylinder; an accumulator provided in a hydraulic line between the hydraulic pump and the hydraulic cylinder and absorbing pressure fluctuations of the hydraulic cylinder; a switching valve device that switches to a first state in which the vibration suppression function is activated by allowing the flow of hydraulic fluid from the hydraulic cylinder to the accumulator and simultaneously allowing the flow of hydraulic fluid from the hydraulic cylinder to a tank, and a second state in which the vibration suppression function is stopped by blocking the flow of hydraulic fluid from the hydraulic cylinder to the accumulator and simultaneously blocking the flow of hydraulic fluid from the hydraulic cylinder to the tank; an operating device that outputs an operation instruction for the work device; and the hydraulic cylinder The apparatus further comprises a pressure sensor for detecting pressure, an operation detector for detecting the operation instruction from the operating device, a speed sensor for detecting the rotational speed of the wheel, a hose rupture valve installed in the hydraulic line and having the function of preventing the leakage of hydraulic fluid from the hydraulic cylinder to the hydraulic line when the hydraulic line is broken, and a release valve capable of switching between maintaining or releasing the function of the hose rupture valve, wherein the accumulator is connected to the hydraulic cylinder through the hose rupture valve, and the control device disables the control of the vibration suppression function even when the effective control of the vibration suppression function is indicated by the vibration suppression instruction device when the vehicle body is jacked up by the working device.A wheeled construction machine characterized by, when the effectiveness of the control of the vibration suppression function is indicated by the vibration suppression indicator device, controlling the switching valve device to the first state or the second state based on the detection value of the pressure sensor, the detection value of the operation detector, and the detection value of the speed sensor; when controlling the switching valve device to the first state, controlling the release valve so that the function of the hose rupture valve is released; and when controlling the switching valve device to the second state, controlling the release valve so that the function of the hose rupture valve is maintained. Claim 2 A wheeled construction machine according to claim 1, wherein the working device comprises a boom, an arm, and a bucket, the hydraulic cylinder is a boom cylinder that moves the boom in an upward direction by supplying hydraulic fluid to the bottom chamber and moves the boom in a downward direction by supplying hydraulic fluid to the rod chamber, the pressure sensor detects the pressure of the bottom chamber of the boom cylinder, and the control device controls the switching valve device to the second state when the detection value of the pressure sensor is lower than a preset threshold when the effective control of the vibration suppression function is indicated by the vibration suppression indicator device. Claim 3 A wheel-type construction machine according to claim 1, comprising an axle capable of oscillating relative to the vehicle body while rotatably supporting the wheel, and a locking mechanism that prevents oscillation of the axle, wherein the locking mechanism is controlled to switch to either a locked state or an unlocked state, and wherein the control device controls the switching valve device to the first state or the second state based on the state of the locking mechanism in addition to the detection value of the pressure sensor, the detection value of the operation detector, and the detection value of the speed sensor when the effective control of the vibration suppression function is indicated by the vibration suppression indicator device. Claim 4 A wheeled construction machine according to claim 1, comprising an overload alarm indicator device that directs an overload alarm control to issue an alarm when the load of the load-hanging operation by the work device is excessive, and wherein the control device controls the switching valve device to the first state or the second state based on the presence or absence of the overload alarm control instruction from the overload alarm indicator device in addition to the detection value of the pressure sensor, the detection value of the operation detector, and the detection value of the speed sensor when the effective control of the vibration suppression function is indicated by the vibration suppression indicator device. Claim 5 delete Claim 6 delete

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