JP2016061386A - Work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work machine capable of efficiently warming up an engine.SOLUTION: A work machine comprises: an engine 34; two tilting pumps 19a and 19b; hydraulic motors 8a and 8b which are connected to the tilting pumps 19a and 19b through closed circuits; a hydraulic oil tank 29; actuators 20 and 21; control valves 22 and 23 which control flows of pressure oil supplied to the actuators 20 and 21; a pilot pump 26 which discharges hydraulic oil in the hydraulic oil tank 29 as the pressure oil; pilot operation devices 24 and 25 which generate pilot pressure for the control valves 22 and 23 by controlling the flow of the pressure oil from the pilot pump 26; a relief pipe conduit 43 which connects a discharge pipe conduit 38 of the pilot pump 26 with the hydraulic oil tank 29; a relief valve 28a installed on the relief pipe conduit 43; and a warming-up device 30a which is installed on the discharge pipe conduit 38 and increases pressure thereof to relief pressure by the relief valve 28a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work machine including a warm-up device.

  As a work machine equipped with a warm-up device, with the operation of the work machine locked, pressure oil discharged from the hydraulic pump is supplied to the pilot circuit and returned to the tank so that the work machine does not malfunction. In order to improve the efficiency of warm-up operation, a proposal has been made (see Patent Document 1).

JP 2003-184827 A

  However, since the working machine of Patent Document 1 simply increases the operating oil temperature by simply circulating the pilot circuit when performing the warming-up operation, and does not apply a load to the engine, the engine or engine coolant is warmed up. Not enough to

  This invention is made | formed in view of the said situation, and it aims at providing the working machine which can warm up an engine etc. efficiently.

  To achieve the above object, a first invention includes an engine, a bi-pump pump driven by the engine, a hydraulic motor connected to the bi-pump pump in a closed circuit, a hydraulic oil tank, an actuator, A control valve that controls the flow of pressure oil supplied to the actuator, a pilot pump that is driven by the engine and discharges the hydraulic oil in the hydraulic oil tank as pressure oil, and a control valve that controls the flow of pressure oil from the pilot pump A pilot operating device that generates a pilot pressure for the pilot pump, a relief pipe that connects the pilot pump's discharge line and hydraulic oil tank, a relief valve that is provided in the relief line, and a pilot pump's discharge line. And a warming-up device for increasing the pressure of the pipe line to the relief pressure by the relief valve.

  According to a second invention, in the first invention, the actuator pump that discharges the hydraulic oil in the hydraulic oil tank as pressure oil, the second relief pipe that connects the discharge pipe of the actuator pump and the hydraulic oil tank, A second relief valve provided in the relief line of 2 and a second warm-up device provided in the discharge line of the actuator pump for increasing the pressure of the discharge line to the relief pressure by the second relief valve. It is characterized by having.

  According to a third invention, in the first invention, the warm-up device includes a valve for shutting off the pressure oil flowing through the discharge pipe of the pilot pump.

  According to a fourth aspect of the present invention, in the third aspect, the lock lever that shuts off the pilot pressure applied to the control valve by switching to the lock position, and at least one of the engine coolant temperature or the hydraulic oil temperature is equal to or less than each set temperature. And a control device that outputs a signal instructing the warming-up operation to the warming-up device on condition that the lock lever is in the locked position.

  ADVANTAGE OF THE INVENTION According to this invention, the working machine which can warm up an engine etc. efficiently can be provided.

1 is a side view of a work machine according to a first embodiment of the present invention. FIG. 2 is a top view of FIG. 1. It is a front view of FIG. 1 is a circuit diagram of a hydraulic circuit system provided in a work machine according to a first embodiment of the present invention. It is a flowchart which shows the execution procedure of the warming-up operation by a control apparatus. It is a circuit diagram of the hydraulic circuit system with which the working machine which concerns on 2nd Embodiment of this invention is provided.

<First Embodiment>
(Constitution)
1. 1 is a side view of a working machine according to the present embodiment, FIG. 2 is a top view thereof, and FIG. 3 is a front view thereof. As shown in FIGS. 1 to 3, in the present embodiment, an explanation will be given taking an irregular terrain vehicle as an example of a work machine. In the present specification, the left and right in FIG. 1 are the front and rear of the rough terrain vehicle.

  The rough terrain vehicle 1 shown in FIG. 1 to FIG. 3 is a crawler type vehicle, and dumps or the like enter in unpaved areas such as mud belts, wetlands, and forest roads, and at sites such as revetment and dam construction. It is also suitable for driving in difficult places. The objects to be transported by the rough terrain vehicle 1 include, for example, stones and the like to be carried to the work site such as revetment work and dam work in addition to mud and wood generated at the work site.

  As shown in FIG. 1, the rough terrain vehicle 1 includes a traveling device 2, a turning wheel 3, and a turning body 4. Hereinafter, each component will be described.

  The traveling device 2 is for traveling the rough terrain vehicle 1 by itself. The traveling device 2 includes a track frame 5, driving wheels 6, driven wheels 7, a driving device (hydraulic motor) 8 and a crawler belt 9. As shown in the figure, the driving wheel 6, the driven wheel 7, the hydraulic motor 8 and the crawler belt 9 are provided in pairs.

  The truck frame 5 extends in the front-rear direction of the rough terrain vehicle 1. Drive wheels 6 and driven wheels 7 are provided at the front and rear ends of the left and right sides of the track frame 5. The output shaft of the hydraulic motor 8 is connected to the drive wheel 6. The crawler belt 9 is wound around the driving wheel 6 and the driven wheel 7.

  As shown in FIG. 3, the swivel wheel 3 is provided on the upper surface of the track frame 5, and supports the swivel body 4 so as to be turnable with respect to the traveling device 2.

  The revolving structure 4 includes a base frame 10, a cab 11, a power unit (power unit) 12, and a vessel 13.

  The base frame 10 is provided on the turning wheel 3 so as to extend in the front-rear direction. A cab 11, a power unit 12, and a vessel 13 are placed on the base frame 10.

  The cab 11 is provided on the front side of the base frame 10. A lock lever 45 is provided in the cab 11. The lock lever 45 is configured to be switchable between a work position and a lock position. By switching the lock lever 45 to the work position, traveling, turning and raising / lowering of the vessel in the rough terrain vehicle 1 are allowed. On the other hand, by switching the lock lever 45 to the lock position (position shown in FIG. 1), pilot pressure (not shown) for operating both tilt pumps 19a and 19b, which will be a drive source of the hydraulic motor 8 described later, and a control valve The pilot pressure applied to 22, 23 (described later) is cut off, and the running, turning, and vessel raising / lowering operations in the rough terrain vehicle 1 are locked.

  The power unit 12 is provided on the rear side of the cab 11. The power unit 12 includes an engine (which will be described later), a hydraulic pump, a hydraulic oil tank, a radiator assembly (a radiator ASSY), and the like that serve as a power source for the rough terrain vehicle 1.

  The vessel 13 is provided on the rear side of the power unit 12 and is formed in a box shape having an open upper surface (see FIG. 2). The rear end of the vessel 13 is attached to the base frame 10 via a pin 22. The vessel 13 is provided so as to be rotatable in the vertical direction with respect to the base frame 10 around the pin 22, that is, to be raised and lowered.

A protector 49 that is curved so as to protrude above the power unit 12 is provided on the front side of the vessel 13. The protector 49 is used to protect the cab 11 and the power unit 12 from the transport object when the transport object is loaded on the vessel 13.
2. Hydraulic Circuit System FIG. 4 is a circuit diagram of a hydraulic circuit system provided in the work machine according to the present embodiment. The hydraulic circuit system 15 includes a traveling circuit 16, a pilot circuit 17, an actuator circuit 18, an engine unit 46, a control device 50, and the like.

Engine unit The engine unit 46 includes an engine 34 and a radiator 35. As shown in FIG. 4, the engine 34 is connected to bi-inclination pumps (HST pumps) 19 a and 19 b, a pilot pump 26 and an actuator pump 27 via a shaft 37 and a coupling. The engine 34 includes an engine speed measurement unit (not shown) that measures the engine speed.

  The radiator 35 has a function of cooling the engine coolant. The engine 34 and the radiator 35 are connected by pipe lines 34a and 34b. The pipe 34a is provided with a thermometer 36 for measuring the temperature of the engine cooling water (engine cooling water temperature).

Traveling circuit The traveling circuit 16 includes both tilting pumps 19a and 19b. Both tilting pumps 19a, 19b are provided with a both tilting swash plate mechanism having a pair of input / output ports and a regulator for adjusting the tilt angle of both tilting swash plates. The generated pilot pressure is supplied to this regulator, so that the direction of suction and discharge of pressure oil and the discharge flow rate are controlled. Both tilting pumps 19 a and 19 b are variable displacement hydraulic pumps and are driven by the engine 34. Both tilting pumps 19a and hydraulic motor 8a are connected by pipes 52a and 52b to form a closed circuit. Similarly, both tilt pumps 19b and the hydraulic motor 8b are connected by pipes 53a and 53b to form a closed circuit. The hydraulic motors 8 a and 8 b correspond to the left and right hydraulic motors 8 of the traveling device 2.

Pilot circuit The pilot circuit 17 includes a pilot pump 26, an electromagnetic switching valve 33, pilot operating devices 24 and 25, a discharge conduit 38, a relief valve 28a, a relief conduit 43, a warming device 30a, and the like.

  The pilot pump (for example, gear pump) 26 is driven by the engine 34, sucks the hydraulic oil stored in the hydraulic oil tank 29, and discharges it as pressure oil to the discharge pipe 38. The hydraulic oil tank 29 is provided with a thermometer 48 for measuring the hydraulic oil temperature. The discharge line 38 of the pilot pump 26 is connected to the pilot operating devices 24 and 25.

  The electromagnetic switching valve 33 is provided in the discharge pipeline 38. The electromagnetic switching valve 33 is electrically connected to the lock lever position detection unit 51, and the opening and closing of the discharge pipe 38 are switched according to a signal from the lock lever position detection unit 51. More specifically, when the lock lever 45 is in the locked position (in the raised state), the electromagnetic switching valve 33 blocks the discharge pipe 38 and switches the lock lever 45 to the working position (in the state where the lever is tilted horizontally). The discharge line 38 is opened.

  The pilot operating device 24 includes pressure reducing valves 24a and 24b and an operating lever 24c. The pilot operating device 24 has a function of generating a pilot pressure for the pilot pressure receiving portions 22a and 22b of the control valve 22 by controlling the flow of pressure oil from the pilot pump 26 with the pressure reducing valves 24a and 24b. A discharge line 38 is connected to the primary ports of the pressure reducing valves 24a and 24b. Pilot pipelines 40a and 40b are connected to the secondary ports of the pressure reducing valves 24a and 24b, respectively. The pilot pipelines 40a and 40b are connected to the pressure receiving portions 22a and 22b of the control valve 22, respectively. When the operation lever 24c of the pilot operating device 24 is operated, the pilot pressure generated according to the operation amount acts on the pressure receiving portion 22a or the pressure receiving portion 22b of the control valve 22 according to the operation direction, and the control valve 22 is driven. .

  The pilot operating device 25 includes pressure reducing valves 25a and 25b and an operating lever 25c. The pilot operating device 25 has a function of generating a pilot pressure for the pilot pressure receiving portions 23a and 23b of the control valve 23 by controlling the flow of pressure oil from the pilot pump 26 by the pressure reducing valves 25a and 25b. A discharge line 38 is connected to the primary ports of the pressure reducing valves 25a and 25b. Pilot pipe lines 41a and 41b are connected to the secondary ports of the pressure reducing valves 25a and 25b, respectively. The pilot pipelines 41a and 41b are connected to pressure receiving portions 23a and 23b of the control valve 23, respectively. When the operation lever 25c is operated, the pilot pressure generated according to the operation amount acts on the pressure receiving portion 23a or the pressure receiving portion 23b of the control valve 23 according to the operation direction, and the control valve 23 is driven.

  The relief line 43 branches off from the discharge line 38 and connects the discharge line 38 and the hydraulic oil tank 29. The relief pipe 43 is provided with a relief valve 28a. The relief valve 28 a has a function of defining the maximum pressure of the discharge pipe 38 and protecting the discharge pipe 38. The relief pipe 43 may be connected to the pipe 47 upstream of the oil cooler 31 so that the pressure oil flowing through the relief pipe 43 is returned to the tank 29 via the oil cooler 31.

  The warming-up device 30 a is provided downstream of the branch position of the relief pipe 43 in the discharge pipe 38 (downstream in the flow direction of pressure oil) and upstream of the electromagnetic switching valve 33. The warming-up device 30a has a function of increasing the pressure of the discharge pipe 38 to the relief pressure by the relief valve 28a. In the present embodiment, the warm-up device 30a is configured by an electromagnetic switching valve. The warm-up device 30a is driven by a signal from the control device 50. When the warm-up device 30a receives a signal from the control device 50, the warm-up device 30a shuts off the discharge conduit 38.

Actuator circuit The actuator circuit 18 includes an actuator pump 27, control valves 22 and 23, a vessel cylinder (actuator) 20, a swing motor (actuator) 21, a discharge pipe 42, a relief valve (second relief valve) 28b, and a relief pipe. A passage (second relief conduit) 44, a warming-up device (second warming-up device) 30b, an oil cooler 31, and the like are provided.

  An actuator pump (for example, a gear pump) 27 is driven by the engine 34, sucks the hydraulic oil stored in the hydraulic oil tank 29, and discharges it as pressure oil to the discharge line 42. A discharge line 42 of the actuator pump 27 is connected to the control valves 22 and 23. In this example, the control valves 22 and 23 are connected in series to the actuator pump 27 via the discharge pipe 42.

  The control valve 22 is connected to a turning motor 21 for driving the turning wheel 3. The control valve 22 is driven by receiving the pilot pressure generated by the pilot operating device 24 at the pressure receiving portion 22a or the pressure receiving portion 22b, and has a function of controlling the flow (direction and flow rate) of the pressure oil supplied to the turning motor 21. . When pressure oil from the actuator pump 27 is supplied to the turning motor 21 via the control valve 22, the turning wheel 3 is driven by the turning motor 21 and the turning body 4 turns. The pressure oil that has driven the turning motor 21 returns to the hydraulic oil tank 29 via the control valve 22 and the conduit 47. An oil cooler 31 is provided in the pipe 47, and the pressure oil that returns to the hydraulic oil tank 29 is cooled by the oil cooler 31.

  The control valve 23 is connected to a vessel cylinder 20 for raising and lowering the vessel 13. The control valve 23 is driven by receiving the pilot pressure generated by the pilot operating device 25 at the pressure receiving portion 23 a or the pressure receiving portion 23 b and has a function of controlling the flow of pressure oil supplied to the vessel cylinder 20. As described above, pressure oil is guided to the control valve 23 through the neutral position of the control valve 22 so that the vessel cylinder 20 can be driven when the turning is stopped. When the pressure oil from the actuator pump 27 guided through the control valve 22 is supplied to the vessel cylinder 20 with the flow (direction and flow rate) controlled by the control valve 23, the pressure oil supply direction and supply flow rate are changed. Accordingly, the vessel 13 of the rough terrain vehicle 1 moves up and down. The pressure oil that has driven the vessel cylinder 20 returns to the hydraulic oil tank 29 via the control valve 23 and the pipe 47.

  The relief pipe 44 is branched from the discharge pipe 42 and connects the discharge pipe 42 and the hydraulic oil tank 29. A relief valve 28 b is provided in the relief conduit 44. Since the structure of the relief valve 28b is the same as that of the relief valve 28a, it is omitted.

  The warming-up device 30b is provided on the downstream side of the branch position of the relief pipe 44 in the discharge pipe 42 (downstream in the flow direction of pressure oil) and on the upstream side of the control valve 22. The warming-up device 30b has a function of increasing the pressure in the discharge pipe 42 to the relief pressure by the relief valve 28b. The warm-up device 30b is driven by a signal from the control device 50.

-Control device The control device 50 is configured such that at least one of the engine coolant temperature or the hydraulic oil temperature is not more than each set temperature, the lock lever 45 is in the lock position, and the engine speed is the set engine speed (idle engine speed or It is configured to output a signal instructing the warm-up operation to the warm-up devices 30a and 30b on the condition that all of the following are satisfied. In the present embodiment, the above condition is referred to as a warm-up condition.

(Operation)
The operation of the work machine according to the present embodiment will be described.

  When the traveling operation, the turning operation, or the dumping operation is performed, the engine 34 is started, and the lock lever 45 of the cab 11 is switched from the lock position to the work position. The engine 34 drives both tilt pumps 19a and 19b, the pilot pump 26, and the actuator pump 27. Since the lock lever 45 is in the working position, no signal (a signal for instructing the warm-up operation) is transmitted from the control device 50 to the warm-up devices 30a and 30b, and the warm-up devices 30a and 30b are connected to the discharge pipes 38 and 42, respectively. It is open. Similarly, since the lock lever 45 is in the working position, the electromagnetic switching valve 33 opens the discharge conduit 38.

Traveling operation When a travel operation device (not shown) is operated, the tilt angle of the swash plate of both tilt pumps 19a, 19b is controlled by the pilot pressure generated in response to the operation, and from both tilt pumps 19a, 19b The pressure oil discharge direction and flow rate are controlled. The pressure oil discharged from both tilt pumps 19a and 19b is supplied to hydraulic motors 8a and 8b. The hydraulic motors 8a and 8b are driven at a rotational direction and a rotational speed corresponding to the pressure oil supply direction and the supply flow rate. Thereby, the rough terrain vehicle 1 travels at a traveling direction and speed according to the operation of the travel operation device.

Turning operation When the operation lever 24c of the pilot operating device 24 is operated, the pilot pressure corresponding to the operation amount acts on the pressure receiving portion 22a or the pressure receiving portion 22b of the control valve 22 according to the operation direction, and the control valve 22 is driven from the neutral position. Is done. As a result, the pressure oil from the actuator pump 27 is supplied to the swing motor 21 with the direction and flow rate controlled by the control valve 22, and the swing motor 21 is rotated at a rotation direction and speed according to the pressure oil supply direction and the supplied flow rate. Driven. Thereby, the turning body 4 turns with respect to the traveling device 2 at a direction and speed according to the operation of the pilot operating device 24.

Dump operation When the operation lever 25c of the pilot operating device 25 is operated, the pilot pressure corresponding to the operation amount acts on the pressure receiving portion 23a or the pressure receiving portion 23b of the control valve 23 according to the operation direction, and the control valve 23 is driven from the neutral position. Is done. As a result, the pressure oil from the actuator pump 27 is supplied to the vessel cylinder 20 with the direction and flow rate controlled by the control valve 23, and the vessel cylinder 20 is rotated at the rotation direction and speed according to the pressure oil supply direction and supply flow rate. Driven. Thereby, the vessel 13 moves up and down at a direction and speed according to the operation of the pilot operating device 25.

As described above, in the rough terrain vehicle 1 according to the present embodiment, when the warm-up condition is satisfied, the warm-up operation is executed according to the signal from the control device 50. FIG. 5 is a flowchart showing a procedure for executing the warm-up operation by the control device 50. Hereinafter, the execution procedure of the warm-up operation will be described with reference to FIG.

  The control device 50 acquires the engine coolant temperature measured by the thermometer 36 (S1), and determines whether the acquired engine coolant temperature is equal to or lower than a set temperature (for example, 70 ° C.) (S2). When the engine coolant temperature is equal to or lower than the set temperature, the control device 50 acquires a signal detected by the lock lever position detector 51 (S3), and based on the signal from the lock lever position detector 51, the lock lever 45 is obtained. Is determined to be in the locked position (S4). When the lock lever 45 is in the locked position, the control device 50 acquires the engine speed measured by the engine speed measuring unit (S5), and determines whether or not the acquired engine speed is equal to or less than the set speed. Judgment is made (S6). The set rotational speed refers to an idle rotational speed of the engine 34 or a rotational speed set in the vicinity thereof. When the acquired engine speed is equal to or lower than the set speed, the warm-up condition described above is satisfied. In this case, the control device 50 outputs a signal instructing the warm-up operation to the warm-up devices 30a and 30b, executes the warm-up operation, and ends the procedure of FIG. 5 (S7). The operation of the hydraulic circuit system 15 during the warm-up operation will be described later.

  On the other hand, when the engine coolant temperature is higher than the set temperature in the previous (S2), the control device 50 acquires the hydraulic oil temperature of the hydraulic oil tank 29 measured by the thermometer 48 (S8). It is determined whether the hydraulic oil temperature is equal to or lower than a set temperature (for example, 50 ° C.) (S9). When the hydraulic oil temperature is equal to or lower than the set temperature, the control device 50 returns the procedure to the above (S3).

  When the lock lever 45 is not in the locked position in (S4), when the engine speed is higher than the set speed in (S6), or when the hydraulic oil temperature is higher than 50 ° C. in (S9), The control device 50 does not output a signal instructing the warm-up operation to the warm-up devices 30a and 30b, and ends the procedure of FIG. 5 without executing the warm-up operation (S10).

  The control device 50 repeatedly executes the procedure of FIG. 5 at set time intervals (for example, every second) while the power is on. Thus, the warm-up operation is continuously executed while the warm-up condition is satisfied, and is terminated or interrupted when the warm-up condition is not satisfied.

  The operation of the hydraulic circuit system 15 during the warm-up operation will be described. When the warm-up device 30a, 30b receives a signal from the control device 50, the warm-up device 30a, 30b switches from the open position to the shut-off position and shuts off the discharge pipelines 38, 42. To do. When the discharge line 38 is shut off, the pressure in the discharge line 38 is increased to the relief pressure by the relief valve 28a, and the relief valve 28a is opened, and the total amount of pressure oil discharged from the pilot pump 26 passes through the relief valve 28a. And returned to the hydraulic oil tank 29. Similarly, when the discharge line 42 is shut off, the pressure in the discharge line 42 is increased to the relief pressure by the relief valve 28b, and the relief valve 28b is opened and the total amount of pressure oil discharged from the actuator pump 27 is reduced. It is returned to the hydraulic oil tank 29 via 28b.

(effect)
(1) According to this embodiment, the discharge pipes 38 and 42 of the pilot pump 26 and the actuator pump 27 are shut off by the warm-up devices 30a and 30b, and the relief valves 28a and 28b are operated, so Can be loaded. Thereby, the engine 34 can be warmed up efficiently, and the temperature of the engine cooling water can also be efficiently raised to the set temperature. Further, the hydraulic oil temperature can be efficiently raised to the set temperature by increasing the pressure.

  (2) When the pressure in the discharge pipes 38 and 42 is increased, for example, it is conceivable to provide a throttle in the pipe 47 connected to the hydraulic oil tank 29. However, in the rough terrain vehicle 1 according to the present embodiment, a pilot pump is used as the actuator pump 27 that supplies pressure oil to the auxiliary machinery (the turning motor 21 and the vessel cylinder 20) by applying a closed circuit to the traveling circuit 16. There is an advantage that a small-sized pump equivalent to 26 can be employed and the operation tank 29 can be configured compactly. When the small-capacity pilot pump 26 and the actuator pump 27 are used, there is no allowance for the liquid supply pressure, and the load due to the restriction is limited within the range of the relief pressure by the relief valves 28a and 28b. For this reason, a configuration in which a throttle is provided in the pipe 47 to reduce the flow rate of the return oil may not ensure a sufficient engine load for efficiently warming up the engine 34. Further, in the configuration in which the throttle is provided in the pipe line 47, the flow rate of the return oil to the hydraulic oil tank 29 is continuously throttled, so that the operation of the components (turning, raising and lowering of the vessel, etc.) of the rough terrain vehicle 1 becomes dull. there is a possibility. Furthermore, since the pressure oil is supplied to the pilot operating devices 24 and 25 during the warm-up operation, the rough terrain vehicle 1 may malfunction.

  Therefore, when the pressure of the discharge pipes 38 and 42 is increased, for example, the relief valves 28a and 28b are operated by shutting off the pipe 47 with a shutoff valve, and the pressure oil discharged from the pilot pump 26 and the actuator pump 27 is used. It is conceivable to apply the engine load by making the maximum use of the range of the relief pressure by returning the total amount of the oil to the hydraulic oil tank 29 via the relief valves 28a and 28b. In this case, however, relief pressure can be applied to all of the oil passages from the pilot pump 26 and the actuator pump 27 to the pipe 47 during the warm-up operation. Therefore, a high pressure pipe such as a high pressure hose must be used for all of this portion. I must. High pressure resistant piping is expensive and has poor pipeability (handling) compared to normal piping. Therefore, a configuration that uses high pressure resistant piping more than necessary is necessary to accommodate the hydraulic circuit system 15 in a narrow power unit 12. It is not preferable.

  On the other hand, in the present embodiment, by providing the warm-up devices 30a and 30b in the discharge pipes 38 and 42, the relief pressure can be applied to the engine to the maximum while the relief pressure is applied. Since the range can also be minimized, it is possible to reduce the cost of the hydraulic circuit system and increase the installation space, and it can be suitably applied to work machines that are downsized using closed circuits. it can.

  (3) In the present embodiment, the warm-up operation is executed by shutting off the discharge pipeline 38 by the warm-up device 30a. Therefore, the pressure oil is not supplied to the pilot operating devices 24 and 25 while the warm-up operation is being performed, and the malfunction of the rough terrain vehicle 1 can be prevented.

  Although not particularly illustrated, when the electromagnetic switching valve 33 blocks the discharge pipe 38, the pressure oil discharged from the pilot pump 26 to the discharge pipe 38 returns to the hydraulic oil tank 29 via the electromagnetic switching valve 33. It has become. That is, when the lock lever 45 is in the locked position, the discharge pressure oil of the pilot pump 26 is supplied to the pilot operating devices 24 and 25 and the control valves 22 and 23 via the electromagnetic switching valve 33 without performing the original function. Thus, it was merely circulated to the hydraulic oil tank 29, resulting in an energy loss. On the other hand, in the present embodiment, since the warm-up operation can be executed using the pressure oil that has been returned to the hydraulic oil tank 29 without any particular role, it is also rational in terms of energy efficiency.

  (4) In the present embodiment, when at least one of the engine coolant and the hydraulic oil is below each set temperature, assuming that the lock lever 45 is in the lock position and the engine speed is equal to or less than the set speed. Warm-up operation is executed. In other words, when both engine coolant and hydraulic oil are higher than each set temperature and do not require warm-up, warm-up operation is not executed, and it is also an advantage that warm-up operation is executed only when necessary. .

Second Embodiment
FIG. 6 is a circuit diagram of a hydraulic circuit system provided in the work machine according to the present embodiment. In FIG. 6, parts that are the same as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate. As shown in FIG. 6, the hydraulic circuit system 115 according to the present embodiment is different from the hydraulic circuit system 15 according to the first embodiment in that the warm-up device 30b is omitted. Other configurations are the same as those of the first embodiment.

  In 1st Embodiment, the case where the whole quantity of the discharge oil of the pilot pump 26 and the actuator pump 27 was utilized for warming-up operation using the two warming-up apparatuses 30a and 30b was illustrated. However, if a desired warm-up efficiency can be obtained with one of the discharge oil of the pilot pump 26 and the actuator pump 27, one of the warm-up devices 30a and 30b is omitted as in the present embodiment. Can do.

  Further, in the case of the present embodiment, since the warm-up operation is performed by blocking the discharge pipe 38 by the warm-up device 30a, the pilot operation device 24 is performed while the warm-up operation is being performed as in the first embodiment. , 25 is not supplied with pressure oil, and the rough terrain vehicle 1 can be prevented from malfunctioning. In addition, in the present embodiment, the pipeline configuration of the hydraulic circuit system can be simplified as compared with the first embodiment because the warm-up device 30b, the relief valve 28b, the relief pipeline 44, and the like are omitted.

<Others>
In the above, assuming that the lock lever 45 is in the locked position and the engine speed is equal to or lower than the set speed, the case where at least one of the engine coolant and the hydraulic oil is equal to or lower than each set temperature is set as the warm-up condition. Although illustrated, warm-up conditions can be selected. For example, the fact that the lock lever 45 is in the locked position may be excluded from the warm-up condition. In this case, by operating only the warm-up device 30b, it is possible to continue the warm-up operation while operating the rough terrain vehicle 1, so that the warm-up operation is stopped when the warm-up is insufficient and the engine is stopped. It is possible to avoid applying a load. Further, it is possible to cope with a case where it is desired to travel during the warm-up operation.

  In addition, the configuration in which the warm-up operation is automatically executed by the control device 50 when the warm-up condition is satisfied is illustrated, but the configuration is not limited thereto. For example, a forced warm-up switch may be provided so that the warm-up operation can be manually executed by operating the forced warm-up switch.

  Moreover, in 1st Embodiment, although the case where warming-up apparatus 30a, 30b was comprised separately was illustrated, warming-up apparatus 30a, 30b may be comprised integrally.

  Further, the case where the oil discharged from the pilot pump 26 and the actuator pump 27 is shut off by the warm-up devices 30a and 30b is illustrated. However, when the total amount of oil discharged from the pilot pump 26 and the actuator pump 27 is necessary to ensure the desired warm-up performance, the pilot is changed by changing at least one of the warm-up devices 30a and 30b to a throttle. It is also conceivable that the discharged oil of at least one of the pump 26 and the actuator pump 27 is supplied to a subsequent hydraulic circuit.

  Moreover, although the case where two pumps of the pilot pump 26 and the actuator pump 27 are used to supply pressure oil for driving the vessel cylinder 20, the swing motor 21 and the control valves 22 and 23, they are shared by one pump. Configuration is also conceivable. If necessary, a configuration in which the pressure oil supply sources of the vessel cylinder 20 and the swing motor 21 are separated is also conceivable. Thus, when three open circuit pumps are used, one to three warm-up devices can be installed according to the required warm-up performance.

DESCRIPTION OF SYMBOLS 1 Work machine 34 Engine 19a, 19b Bi-rotation pump 8 Hydraulic motor 29 Hydraulic oil tank 20, 21 Actuator 22, 23 Control valve 26 Pilot pump 27 Actuator pump 24, 25 Pilot operation device 38, 42 Discharge line 43 Relief line 44 Second relief pipe line 28a Relief valve 28b Second relief valve 30a Warm-up device 30b Second warm-up device 45 Lock lever 50 Control device

Claims (4)

Engine,
A bi-directional pump driven by the engine;
A hydraulic motor connected to the both tilting pumps in a closed circuit;
A hydraulic oil tank;
An actuator,
A control valve for controlling the flow of pressure oil supplied to the actuator;
A pilot pump driven by the engine and discharging hydraulic oil in the hydraulic oil tank as pressure oil;
A pilot operating device that generates a pilot pressure for the control valve by controlling a flow of pressure oil from the pilot pump;
A relief line connecting the pilot pump discharge line and the hydraulic oil tank;
A relief valve provided in the relief line;
A work machine comprising: a warm-up device that is provided in a discharge pipe of the pilot pump and increases the pressure of the discharge pipe to a relief pressure by the relief valve. The work machine according to claim 1,
An actuator pump that discharges the hydraulic oil in the hydraulic oil tank as pressure oil;
A second relief line connecting the discharge line of the actuator pump and the hydraulic oil tank;
A second relief valve provided in the second relief conduit;
A work machine comprising: a second warming-up device that is provided in a discharge line of the actuator pump and raises the pressure of the discharge line to a relief pressure by the second relief valve. The work machine according to claim 1,
The warming device includes a valve that shuts off the pressure oil flowing through a discharge pipe of the pilot pump. The work machine according to claim 3,
A lock lever that shuts off the pilot pressure applied to the control valve by switching to the lock position;
A control device that outputs a signal instructing the warm-up operation to the warm-up device on condition that at least one of the engine coolant temperature or the hydraulic oil temperature is equal to or lower than each set temperature and the lock lever is in the lock position; A work machine characterized by comprising:

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