JP2018167676A - Axle heat-up device for work vehicle - Google Patents

Abstract

To provide an axle heat-up device for work vehicle that can heat-up axle oil efficiently in a short time.SOLUTION: An axle heat-up device for work vehicle includes: lubricant filled in a casing for axles (3, 3R, 3L) that transmit power of a drive source (16) to a wheel (2); circulation passages (58R, 58L) communicated to an inside of the casing for the axles to circulate the lubricant; and compression heat-up means (56R, 56L, 60R, 60L) interposed in the circulation passages to compress and heat up the lubricant using power of the drive source.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an axle temperature raising device for a work vehicle, and more particularly to a technique for quickly raising the temperature of lubricating oil in an axle that transmits power to wheels.

2. Description of the Related Art Conventionally, work vehicles employing HST (Hydro Static Transmission) configured to supply hydraulic oil discharged from a hydraulic pump driven by an internal combustion engine as a drive source to a hydraulic motor are widely known.
In such work vehicles, the output of the hydraulic motor is transmitted to the drive wheels via the axle.

The axle is internally provided with a reduction gear comprising a gear device for power transmission, and the casing of the axle is filled with axle oil as lubricating oil for the gear device.
By the way, the axle oil has a high viscosity and becomes an operating resistance of the gear device in winter, especially in an environment where the outside air temperature is low, such as in a cold region, and it is difficult to increase the wheel speed when starting the work vehicle. There is a problem that sufficient vehicle speed cannot be obtained.

  Accordingly, in order to raise the temperature of the axle oil, a technique for heating the axle oil with an electric heater using an external power source has been developed in addition to a technique for causing the work vehicle to travel for a while to stir the axle oil (Patent Document 1). ).

Japanese Patent Laid-Open No. 04-90931

However, in the case of a technique in which the work vehicle is allowed to run for a while to stir the axle oil, there is a problem that it takes time to sufficiently raise the temperature when the temperature of the axle oil is extremely low.
In addition, as in the technique described in Patent Document 1, when the axle oil is heated with an electric heater using an external power source, the work place where such an external power source can be secured is limited, and the power consumption is large. There is a problem of lack of practicality. In addition, there is a problem similar to the above in that it takes time to sufficiently raise the temperature when the amount of axle oil is large.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an axle temperature raising device for a work vehicle capable of efficiently raising the temperature of axle oil in a short time. It is in.

In order to achieve the above object, an axle temperature increasing device for a work vehicle according to the present invention has a gear device inside a casing, an axle for transmitting the power of a drive source to wheels via the gear device, and the casing. Lubricating oil filled inside and lubricating the gear device, a circulation path communicating with the inside of the casing and circulating the lubricating oil, and interposed in the circulation path, using the power of the drive source A pressurizing / heating means for pressurizing and raising the temperature of the lubricating oil is provided.
Thereby, the lubricating oil inside the casing of the axle is efficiently pressurized by the pressurizing and heating means using the power of the drive source of the work vehicle in the circulation path, and is quickly heated.

Preferably, a hydraulic motor that operates with hydraulic oil discharged from a hydraulic pump that is driven by the drive source is provided, and the pressurizing and heating means is interposed in the circulation path and is driven by the hydraulic motor and is lubricated. It is preferable to include a lubricating oil pump that discharges oil and a fluid resistance member that is interposed downstream of the lubricating oil pump in the circulation path and loads resistance to the flow of the lubricating oil.
As a result, the lubricating oil pump is driven by the hydraulic motor that operates with the hydraulic oil discharged from the hydraulic pump driven by the drive source, and the lubricating oil is discharged in the circulation path, and the fluid resistance member resists the flow of the lubricating oil. The hydraulic oil circulating through the circulation path is efficiently pressurized and quickly raised in temperature.

The fluid resistance member is preferably a relief valve.
As a result, the pressure of the lubricating oil on the upstream side of the relief valve in the circulation path is increased to a predetermined pressure set in the relief valve, and the operating oil circulating in the circulation path is easily heated.
The fluid resistance member is preferably an orifice.
As a result, the pressure of the lubricating oil on the upstream side of the orifice of the circulation path is increased with a simple configuration using the orifice, and the operating oil circulating in the circulation path is easily heated.

The fluid resistance member is preferably a relief valve and an orifice provided in parallel with the relief valve.
As a result, until the pressure of the lubricating oil on the upstream side of the relief valve in the circulation path reaches a predetermined pressure set in the relief valve, the lubricating oil whose temperature is raised to a certain extent by the orifice is heated to the axle casing. Circulate inside.

  According to the axle temperature raising device for a work vehicle of the present invention, for example, even in a situation where the outside air temperature is low and the temperature of the lubricating oil in the axle is low, the lubricating oil is used as a drive source for the work vehicle in the circulation path. It is possible to effectively pressurize and quickly raise the temperature by a pressure raising means using motive power, and thereby raise the temperature of the axle quickly, thereby effectively reducing the viscosity of the lubricating oil.

  Therefore, if the viscosity of the lubricating oil in the axle is high, the lubricating oil will cause a frictional resistance of the gear device in the axle and the rotational speed of the wheel will not be increased sufficiently. It is possible to quickly reduce the frictional resistance of the inner gear device and to make the work vehicle run smoothly.

It is a figure which shows the tire roller vehicle which is a kind of rolling machine as a working vehicle. It is a schematic block diagram of the hydraulic circuit in a tire roller vehicle. It is a control block diagram for performing operation control of an axle oil heater unit. It is a figure which shows a modification. It is a figure which shows another modification.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Hereinafter, an axle temperature raising device for a work vehicle according to the present invention will be described with reference to the drawings.
FIG. 1 shows a tire roller vehicle 1 which is a kind of a rolling machine as a work vehicle. The tire roller vehicle 1 includes a rolling wheel 2 that also serves as front and rear wheels, and a vehicle body 4 that travels by the rolling wheel 2. A driver's seat 6 on which an operator sits is provided at the upper center of the vehicle body 4. . An operation panel 8 is disposed in front of the driver's seat 6. The operation panel 8 has a handle 10 for steering the tire roller vehicle 1, a forward / reverse lever 11 for switching forward and backward, and a parking of the tire roller vehicle 1. A parking brake SW12 that operates a brake (not shown), a watering pump SW13 that operates a watering pump 34 described later, and the like are provided.

  A part of the vehicle body 4 is configured as a water tank 14. The water tank 14 is a tank that stores water for watering the rolling wheel 2 and the road surface. Specifically, when compacting the asphalt with the compaction wheel 2 in road pavement construction, in order to prevent the asphalt from adhering mainly to the compaction wheel 2, the water tank 14 from the water spray nozzle to the compaction wheel 2 and the asphalt on the road surface. Sprinkle the water inside.

  An engine (drive source) 16 and a hydraulic pump unit 20 are disposed in the front part of the vehicle body 4. In the tire roller vehicle 1, hydraulic motors are used to drive the rolling wheels 2 and to spray water, and the hydraulic pump unit 20 is a plurality of hydraulic pumps that discharge and circulate hydraulic oil to these hydraulic motors. It is configured. As will be described in detail later, the plurality of hydraulic pumps are driven by the engine 16.

  The rolling wheel 2 on the rear wheel side as a drive wheel has four wheels, two of these four wheels form a pair, and each of the two wheels is an axle 3 (axles 3R and 3L described later). It is comprised so that it may drive via. The axle 3 is a device for transmitting power to the rolling wheel 2. The axle 3 is provided with a reduction gear including a gear device for power transmission in a casing, and the casing is lubricated to lubricate the gear device. Axle oil is filled as oil.

Referring to FIG. 2, a schematic configuration diagram of a hydraulic circuit in the tire roller vehicle 1 is shown.
As shown in the figure, the hydraulic pump unit 20 includes a traveling hydraulic pump 22 for operating a pair of left and right traveling hydraulic motors 30, a steering cylinder (not shown), and a steering cylinder for operating a brake cylinder 32. A hydraulic pump 26 for water pump for operating a hydraulic motor 36 for water pump that operates the hydraulic pump 24 for brake and the water spray pump 34 is provided. These hydraulic pump 22 for traveling, hydraulic pump 24 for steering and brake, and water pump A hydraulic pump 26 is connected to the output shaft of the engine 16.

The hydraulic pumps such as the traveling hydraulic motor 30, the water pump hydraulic motor 36, and the like, and the traveling hydraulic pump 22, the steering / brake hydraulic pump 24, the water pump hydraulic pump 26, and the like are connected by hydraulic lines. It is connected. Specifically, in the hydraulic circuit, the traveling hydraulic motor 30 and the traveling hydraulic pump 22 are connected by a hydraulic line 40, and the steering cylinder (not shown), the brake cylinder 32, and the steering / brake hydraulic pump 24 are hydraulic. The hydraulic pump 36 for water pump and the hydraulic pump 26 for water pump are connected by a hydraulic line 44, and the hydraulic oil can be circulated through the hydraulic lines 40, 42, 44, respectively. Has been. The hydraulic pipes 40, 42, 44 are connected to pass through the hydraulic oil tank 70, and are configured to receive a sufficient supply of hydraulic oil from the hydraulic oil tank 70.
Here, the traveling hydraulic motor 30 and the traveling hydraulic pump 22, and the water pump hydraulic motor 36 and the water pump hydraulic pump 26 are configured as HST (Hydro Static Transmission).

  Of the hydraulic pipes 44 that connect the water pump hydraulic motor 36 and the water pump hydraulic pump 26, the supply pipe 44 a in the upstream part and the return pipe 44 b in the downstream part of the water pump hydraulic motor 36. A bypass pipe 44c is bridged between them, and a water pump hydraulic motor operation switching valve 45 comprising a two-port solenoid valve is interposed in the bypass pipe 44c. The water pump hydraulic motor operation switching valve 45 has a function of switching between operation and stop of the water pump hydraulic motor 36. In a state where the water pump hydraulic motor operation switching valve 45 is located on the valve opening side, the hydraulic oil bypasses the water pump hydraulic motor 36 from the supply line 44a to the return line 44b via the bypass line 44c. Thus, the water pump hydraulic motor 36 does not operate and watering by the watering pump 34 is not performed. On the other hand, in a state where the water pump hydraulic motor operation switching valve 45 is located on the valve closing side, the hydraulic oil flows from the supply pipe 44 a through the water pump hydraulic motor 36 to the return pipe 44 b, and the water spray pump 34. Is activated and watering can be performed.

Further, a relief pipe 44d is further extended between the supply pipe 44a and the return pipe 44b in parallel with the bypass pipe 44c, and a relief valve 46 is interposed in the relief pipe 44d. . The relief valve 46 opens when the pressure of the hydraulic oil in the supply pipe 44a rises to a predetermined pressure set in advance, and allows the hydraulic oil to flow into the return pipe 44b. As a result, excessive supply of hydraulic pressure to the water pump hydraulic motor 36 is prevented.
A filter unit 48 is interposed on the downstream side of the return pipe 44b. The filter unit 48 removes foreign matters mixed in the hydraulic oil.

  Thus, when the traveling hydraulic pump 22, the steering / brake hydraulic pump 24 and the water pump hydraulic pump 26 are driven by the engine 16, the hydraulic oil is sucked up from the hydraulic oil tank 70 and hydraulic lines 40, 42, 44, whereby the traveling hydraulic motor 30 is driven and the tire roller vehicle 1 travels according to the driving operation of the forward / reverse lever 11 or the like by the operator, and the water pump hydraulic motor operation switching valve 45 is closed. When the water pump hydraulic motor 36 is driven and the watering pump SW13 is operated in the state of being switched to the side, the watering pump 34 is actuated to spray water, and the handle 10 and the brake pedal (not shown) are operated. Accordingly, hydraulic oil is supplied to the steering cylinder and the brake cylinder 32.

By the way, as described above, the casing of the axle 3 (the axles 3R and 3L) is filled with axle oil as a lubricating oil. In the tire roller vehicle 1 according to the present invention, in the case where the outside air temperature is low, An axle oil heater unit 50 for warming the axle oil filled in the casing of the axle 3 is provided. Hereinafter, the axle oil heater unit 50 will be described.
As shown in FIG. 2, a hydraulic line 51 is provided so as to branch from the supply line 44a and join the return line 44b. Specifically, an axle oil heater operation switching valve 52 composed of a three-port solenoid valve is interposed in the supply line 44a, and the hydraulic line 51 supplies hydraulic oil by switching the axle oil heater operation switching valve 52. The pipe 44a can be branched to the hydraulic pipe 51 side.

  A hydraulic motor 54 for an axle oil pump is interposed in the hydraulic line 51. Two axle oil pumps (lubricating oil pump, pressurized temperature raising means) 56R and 56L are connected to the output shaft of the hydraulic oil motor 54 for the axle oil pump. Axle oil pumps 56R and 56L are interposed in oil passages (circulation passages) 58R and 58L, respectively. Oil passage 58R has both ends connected to one axle 3R of axle 3, and oil passage 58L has both ends connected to the other axle 3L. It is connected.

Specifically, the oil passages 58R and 58L are connected to the axles 3R and 3L so as to be able to communicate with the axle oil reservoirs in the casings of the axles 3R and 3L, respectively. As a result, the axle oil pumps 56R and 56L are operated, whereby the axle oils of the axles 3R and 3L are discharged from the axle oil pumps 56R and 56L and can be circulated through the oil passages 58R and 58L, respectively.
Relief valves (fluid resistance members, pressurized temperature raising means) 60R and 60L are interposed in the oil passages 58R and 58L, respectively. The relief valves 60R and 60L open when the pressure of the axle oil in the oil passages 58R and 58L rises to a predetermined pressure set in advance, and allow circulation of the axle oil in the oil passages 58R and 58L.

Filters 62R and 62L are interposed in the oil passages 58R and 58L. The foreign substances mixed in the axle oil are removed by the filters 62R and 62L. The axles 3R and 3L are provided with axle oil temperature sensors 64R and 64L for detecting the temperature of the axle oil, respectively.
Thus, the axle oil heater unit 50 mainly includes the hydraulic line 51, the axle oil heater operation switching valve 52, the axle oil pump hydraulic motor 54, the axle oil pumps 56R and 56L, the oil passages 58R and 58L, the relief valve 60R, and the like. It is composed of 60L.

Thus, when the axle oil heater operation switching valve 52 is opened to the hydraulic line 51 side in a state where the water pump hydraulic motor operation switching valve 45 is switched to the valve closing side, the hydraulic oil passes through the hydraulic line 51. Then, the hydraulic motor 54 for the axle oil pump and the axle oil pumps 56R and 56L are operated, and the axle oil of the axles 3R and 3L is sucked into the oil passages 58R and 58L.
At this time, since the relief valves 60R and 60L do not open unless the predetermined pressure is reached, the relief valves 60R and 60L resist the axle oil in the upstream portion of the relief valves 60R and 60L in the oil passages 58R and 58L. The axle oil is pressurized. When the axle oil is pressurized in this way, the axle oil is warmed and heated up.

Referring to FIG. 3, there is shown a control block diagram according to the present invention for controlling the operation of the axle oil heater unit 50. Hereinafter, the operation control of the axle oil heater unit 50 will be described.
An MCU (microcomputer unit) 80 is mounted on the tire roller vehicle 1. The MCU 80 is configured to perform various controls such as various control valves of the engine 16 and the hydraulic circuit, and includes an input / output device, a storage device, a central processing unit (CPU), and the like.

A forward / reverse lever 11, axle oil temperature sensors 64R and 64L, a parking brake SW12, a watering pump SW13, and the like are electrically connected to the input side of the MCU 80. That is, the MCU 80 receives position information indicating whether the front (F), neutral (N), or rear (R) position is operated from the forward / reverse lever 11 from the axle oil temperature sensors 64R and 64L. The temperature information is input from the parking brake SW12 to the parking brake operation information, and the watering pump SW13 is operated to operate the watering pump 34.
On the other hand, an axle oil heater operation switching valve 52 is connected to the output side of the MCU 80, and the axle oil heater operation switching valve 52 is operated in accordance with input information to raise the pressure of the axle oil.

  Specifically, in a state where the ignition SW (not shown) is operated and the MPU is activated, the position of the forward / reverse lever 11 is operated to neutral (N), and the temperatures of the axle oils of the axles 3R and 3L are predetermined. When the temperature is below (for example, less than 20 ° C.), the parking brake SW12 is turned on and the parking brake is activated, and the watering pump SW13 is turned off and the watering pump 34 is not operated. The switching valve 52 is switched to the side that communicates with the hydraulic line 51, whereby the axle oil heater unit 50 functions, and the pressure increase of the axle oil is performed.

  The axle oil heater operation switching valve 52 once switched to the side communicating with the hydraulic line 51 is in any of the following states, that is, the position of the forward / reverse lever 11 is either front (F) or rear (R). The operated state, the temperature of each axle oil of the axles 3R and 3L is a predetermined temperature or higher (for example, 20 ° C. or higher), the parking brake SW12 is turned off and the parking brake is released, the watering pump SW13 is turned on When the water spray pump 34 is activated, it is switched to the side that communicates with the water pump hydraulic motor 36 and the function of the axle oil heater unit 50 is stopped. The pressure rise is released.

  Thus, according to the axle temperature increasing device for a work vehicle according to the present invention, when the outside air temperature is low and the temperature of each axle oil of the axles 3R and 3L is less than a predetermined temperature, the position of the forward / reverse lever 11 is neutral ( Nx position, the parking brake is activated and the watering pump 34 is not activated, i.e., the tire roller vehicle 1 has not yet started work. 50, the axle oil is circulated through the oil passages 58R and 58L, and is pressurized and warmed by the relief valves 60R and 60L.

Thus, even in a situation where the outside air temperature is low and the temperature of the axle oil is low, the inside of the hydraulic line 44 is circulated by the HST hydraulic oil, specifically, the water pump hydraulic pump 26 operated by the engine 16. By effectively using the circulating hydraulic oil and causing the axle oil heater unit 50 to function, the axle oil is efficiently pressurized and quickly raised in temperature, and the axles 3R and 3L are raised in temperature, thereby increasing the viscosity of the axle oil. It can be effectively reduced.
Therefore, when the viscosity of the axle oil is high, the axle oil becomes a frictional resistance of the gear devices in the axles 3R and 3L, and the rotation speed of the rolling wheel 2 is not sufficiently increased. However, the viscosity of the axle oil is effectively increased. By lowering, even if the outside air temperature is low, it is possible to quickly reduce the frictional resistance of the gear devices in the axles 3R and 3L and to make the tire roller vehicle 1 run smoothly.

Next, a modified example will be described.
In the modification, instead of the relief valves 60R and 60L, as shown in FIG. 4, orifices (fluid resistance members) 61R and 61L are provided in the oil passages 58R and 58L.
As described above, even if the orifices 61R and 61L are interposed in the oil passages 58R and 58L, the orifices 61R and 61L load resistance on the axle oil, so that the axle oil upstream of the orifices 61R and 61L Pressurized, the axle oil can still be warmed, and the same effect as described above can be obtained.

Furthermore, another modified example will be described.
In another modified example, in the oil passages 58R and 58L, as shown in FIG. 5, the relief valves (fluid resistance members) 60R and 60L are bypassed, that is, in parallel with the relief valves 60R and 60L, respectively. Fluid resistance members) 61R and 61L are provided.
As described above, when the relief valves 60R and 60L are provided in the oil passages 58R and 58L, and the orifices 61R and 61L are provided so as to bypass them, the viscosity of the axle oil is high at low temperatures. The amount of oil passing therethrough is small, and a temperature increase corresponding to the set pressure of the relief valves 60R and 60L can be obtained. Further, since the viscosity of the axle oil is low when the temperature is high, the amount of oil passing through the orifices 61R and 61L increases. Therefore, the axle oil is reduced to a pressure corresponding to the diameters of the orifices 61R and 61L, and pressurization more than necessary is suppressed. Therefore, it is possible to achieve both a temperature rising effect at a low temperature and an energy saving effect at a high temperature.

  As a result, the viscosity of the axle oil circulating in the oil passages 58R and 58L can be reduced as a whole at an early stage, and the operating resistance of the gear device in the axles 3R and 3L can be reduced even when the outside air temperature is low. Can be reduced at an early stage, and the tire roller vehicle 1 can be smoothly driven from an early stage.

Although the description of the embodiment of the axle temperature increasing device for a work vehicle according to the present invention has been completed, the present invention is not limited to the above embodiment.
For example, in the above-described embodiment, the tire roller vehicle 1 which is a kind of the rolling machine is described as an example of the work vehicle. However, the present invention is not limited to this and can be applied to any work vehicle provided with an axle.
Further, in the above embodiment, the axle oil heater unit 50 is configured so that the axle oil pumps 56R and 56L are actuated by the axle oil pump hydraulic motor 54. However, the axle oil pumps 56R and 56L may be driven by the engine 16. Is possible.

1 Tire roller vehicle 2 Rolling wheel (wheel)
3, 3R, 3L Axle 4 Car body 16 Engine (drive source)
20 Hydraulic pump unit 26 Hydraulic pump for water pump 44 Hydraulic pipeline 44a Supply pipeline 44b Return pipeline 50 Axle oil heater unit 51 Hydraulic pipeline 52 Axle oil heater switching valve 54 Axle oil pump hydraulic motor 56R, 56L Axle oil Pump (lubricating oil pump, pressure heating means)
58R, 58L Oil path (circulation path)
60R, 60L relief valve (fluid resistance member, pressurization heating means)
61R, 61L Orifice (fluid resistance member)
80 MCU (microcomputer unit)

Claims (5)

An axle having a gear device inside the casing and transmitting the power of the drive source to the wheel via the gear device;
A lubricating oil filled in the casing for lubricating the gear unit;
A circulation path communicating with the inside of the casing and circulating the lubricating oil;
An axle temperature raising device for a work vehicle, comprising a pressure raising temperature raising means that pressurizes and raises the temperature of the lubricating oil that is interposed in the circulation path and uses the power of the drive source. A hydraulic motor that operates with hydraulic oil discharged from a hydraulic pump driven by the drive source;
The pressurizing temperature raising means is interposed in the circulation path and is driven by the hydraulic motor to discharge the lubricant, and is interposed downstream of the circulation path from the lubrication oil pump. The axle temperature raising device for a work vehicle according to claim 1, further comprising a fluid resistance member that applies resistance to the flow of the lubricating oil.   The axle temperature raising device for a work vehicle according to claim 2, wherein the fluid resistance member is a relief valve.   The axle temperature raising device for a work vehicle according to claim 2, wherein the fluid resistance member is an orifice.   The axle temperature raising apparatus for a work vehicle according to claim 2, wherein the fluid resistance member is a relief valve and an orifice provided in parallel with the relief valve.

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