JP2001059562A - Fluid machine incorporating rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss by appropriately adjusting the temperature of lubrication oil present in a closed container in a fluid machine such as a hydraulic pump, a hydraulic motor, a hydrostatic transmission or the like. SOLUTION: In a hydrostatic transmission in which a hydraulic pump mechanism 2 is incorporated in the upper part of the inside of a closed container while a hydraulic motor mechanism 3 is incorporated in the lower part thereof, a cooling water passage 6 is formed, adjacent to the close container. A solenoid valve 65 is connected in a cooling water pipe 64 connected to the cooling water passage 6. When the pressure in a hydraulic circuit is lower than a predetermined value, the solenoid valve 65 is closed while when the pressure is higher than the predetermined value, the solenoid valve 65 is opened so as to cool lubrication oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluid machine represented by a hydraulic pump, a hydraulic motor, an HST (hydrostatic transmission), and the like. In particular, the present invention relates to a measure for reducing a loss horsepower due to the presence of hydraulic oil in a machine in which a rotating body rotates while being immersed in hydraulic oil.

[0002]

2. Description of the Related Art Conventionally, as a transmission mounted on a working vehicle such as a combine or a construction machine, for example, Japanese Patent Application Laid-Open No.
HST disclosed in Japanese Patent No. 129282 is used.

The HST has a configuration in which a hydraulic pump mechanism having an input shaft and a hydraulic motor mechanism having an output shaft are connected by an oil passage. Then, the driving force of the engine is transmitted from the input shaft to the hydraulic pump mechanism, and the hydraulic pressure generated by the hydraulic pump mechanism is supplied to the hydraulic motor mechanism via the oil passage. In the hydraulic motor mechanism, the output shaft rotates according to the supplied hydraulic pressure. Thus, the rotational driving force of the engine is changed and output from the output shaft of the hydraulic motor.

[0004] Specifically, the hydraulic pump mechanism has a plunger block in which a plurality of plungers are incorporated, and is integrally rotatably assembled with the input shaft. The plunger block is housed in a closed container formed by a housing and a center section. The inside of the closed container is filled with hydraulic oil, and the plunger block rotates while each sliding portion is lubricated by the hydraulic oil. By adjusting the inclination angle of the movable swash plate with which the tip of the plunger abuts, the plunger reciprocates to perform a pump action, and high-pressure oil is supplied to the hydraulic motor mechanism. The hydraulic motor mechanism has substantially the same configuration as that of the hydraulic pump mechanism. The hydraulic pressure acting on the plunger of the hydraulic motor mechanism is converted into the rotational force of the plunger block, and the output shaft rotates. Also in this hydraulic motor mechanism, the plunger block rotates in the working oil filled in the closed container formed by the housing and the center section.

[0005]

The inventors of the present invention are conducting various studies in order to improve the power transmission efficiency of the HST. And it discovered that the temperature of the hydraulic oil which exists in an airtight container was one of the factors which greatly affected this efficiency.

That is, when the temperature of the hydraulic oil is relatively low, the viscosity of the hydraulic oil is high, so that the resistance of the plunger block to rotation due to the presence of the hydraulic oil is increased, thereby causing the plunger block to move inside the hydraulic oil. The rotation loss associated with the rotation at the wheel increases, and the loss horsepower also increases.

On the contrary, when the temperature of the hydraulic oil is relatively high, the viscosity of the hydraulic oil may be too low, which may hinder the lubrication performance. If the operating oil temperature is high in a state where the circuit pressure is high, the leak amount of the operating oil from each part of the HST (such as the mating surface between the constituent members) increases, and the supply power ( The power for refueling by the charge pump) increases. In this case also HST
The overall loss horsepower increases, leading to a decrease in efficiency.

Further, the present inventors have recognized that the means for reducing loss horsepower proposed this time can be applied not only to HST but also to other fluid machines such as hydraulic pumps and hydraulic motors. are doing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to control the temperature of hydraulic oil present in a closed vessel with respect to a fluid machine such as a hydraulic pump, a hydraulic motor, and an HST. By properly adjusting, it is possible to reduce the loss horsepower and thereby improve the power transmission efficiency.

[0010]

Means for Solving the Problems-Summary of the Invention-In order to achieve the above object, the present invention adjusts the temperature of hydraulic oil in accordance with a load acting on a rotating body of a fluid machine. Specifically, when the load is low, the viscosity of the operating oil is reduced to reduce the rotation loss of the rotating body, while at the time of high load, the viscosity of the operating oil is increased to reduce the leakage amount of the operating oil.

-Solution Means- Specifically, the first solution means adopted by the present invention is based on a fluid machine in which a rotating body rotates in a container in which hydraulic oil is stored. The fluid machine is provided with a cooling means capable of cooling the working oil in the container, and the cooling means switches between a cooling state and a non-cooling state of the working oil in accordance with a load acting on the rotating body. .

The second solution specifies the specific switching operation. That is, in the first solving means, the cooling means performs the cooling operation of the hydraulic oil only when the load acting on the rotating body exceeds a predetermined value.

According to this particular matter, the cooling oil is not cooled by the cooling means when the load is relatively low. That is, by promoting the temperature rise of the hydraulic oil, its viscosity is reduced, and the resistance to rotation of the rotating body (resistance due to the presence of the hydraulic oil) is reduced. Conversely, when the load is relatively high, the cooling means cools the hydraulic oil. That is, by suppressing a rise in the temperature of the hydraulic oil, a decrease in the viscosity of the hydraulic oil is prevented, and a leak amount of the hydraulic oil from each part of the machine is reduced. By reducing the leak amount, the loss horsepower required to replenish the hydraulic oil loss can be reduced.

[0014] The third means specifically specifies the control temperature of the hydraulic oil by the cooling means. That is, in the second solving means, when the load acting on the rotating body is equal to or less than the predetermined value, the cooling means sets the operating oil temperature to 50 degrees.
° C or higher, and when the load exceeds a predetermined value, the cooling operation is performed so as to control the hydraulic oil temperature to 50 ° C or lower.

The fourth solution specifically specifies the configuration of the cooling means. That is, in the first, second, or third solution, the cooling means switches between a cooling water flow path formed adjacent to the outer surface of the container and a flow state and a non-flow state of the cooling water in the cooling water flow path. Possible switching means and control means for switching the switching means so that the cooling water flows through the cooling water passage only when the load acting on the rotating body exceeds a predetermined value.

According to this specific matter, a state in which the cooling water flows in the cooling water flow path and a state in which the cooling water does not flow are switched with the switching operation of the switching means, and the cooling operation of the hydraulic oil and the non-cooling operation are switched. Be replaced. Further, since the cooling water flow path is formed adjacent to the outer surface of the container, the space required for forming the cooling water flow path can be small.

A fifth solution is to cool the working oil in the working oil circulation oil passage. That is, a fluid machine in which a rotating body rotates in a container in which hydraulic oil is stored is assumed. For this fluid machine, a circulating oil passage for circulating hydraulic oil between the container and the oil tank, a cooling water flow passage through which cooling water flows, and a cooling water flowing through the working oil and cooling water flow passage circulating through the circulating oil passage And a heat exchanger for exchanging heat with the heat exchanger. Further, a switching means capable of switching between a flowing state and a non-flowing state of the cooling water in the cooling water flow path, and allowing the cooling water to flow through the cooling water flow path only when a load acting on the rotating body exceeds a predetermined value. Control means for switching the switching means as described above.

Also according to this specific matter, the cooling operation of the hydraulic oil and the non-cooling operation are switched with the switching operation of the switching means. In particular, since the heat exchange between the hydraulic oil and the cooling water is performed using a special heat exchanger, the heat exchange efficiency is high, and the hydraulic oil can be cooled quickly.

The sixth and seventh means for controlling the temperature of the hydraulic oil by adjusting the circulation amount of the hydraulic oil between the container and the oil cooler. That is, the sixth solving means is based on a fluid machine in which a rotating body rotates in a container in which hydraulic oil is stored. For this fluid machine, a circulating oil passage for circulating hydraulic oil between the container and the oil cooler, and discharge of hydraulic oil from the container to the circulating oil passage only when a load acting on the rotating body exceeds a predetermined value. And discharge permitting means for permitting the discharge.

According to this specific matter, the discharge permitting means permits discharge of the hydraulic oil from the container to the circulation oil passage only when the load exceeds a predetermined value. After being cooled by the oil cooler, the hydraulic oil discharged to the circulation oil passage returns to the inside of the container again, and contributes to a decrease in the temperature of the hydraulic oil in the container. As described above, it is possible to adjust the temperature of the hydraulic oil in the container only by controlling the flow of the hydraulic oil in the circulation oil passage.

According to a seventh aspect, in the sixth aspect, a plurality of hydraulic oil outlets are provided in the container, and each hydraulic oil outlet is connected to a circulation oil passage. Each hydraulic oil outlet is provided with an opening / closing means for opening the hydraulic oil outlet only when the temperature of the hydraulic oil in the container reaches a predetermined temperature. Then, these opening / closing means are set to have different temperatures at which the opening operation is performed. In addition, the discharge permitting means is provided in the circulating oil passage connected to the opening / closing means having the lowest set temperature at which the opening operation is performed among the opening / closing means.

According to this specific matter, when the load is equal to or less than the predetermined value, discharge of the hydraulic oil from the container to the circulation oil passage is prevented by the discharge permitting means. For this reason, even if the operating oil temperature rises to the operating temperature of the opening / closing means having the lowest set temperature for performing the opening operation, the cooling operation of the operating oil is not performed. Thereby, the temperature rise of the hydraulic oil at the time of low load is promoted. Thereafter, when the operating oil temperature rises to the operating temperature of the other opening / closing means, the operating oil is discharged from the container by the opening operation of the opening / closing means, and the operating oil is cooled. Thereby, abnormal rise of the hydraulic oil at the time of low load is prevented.

On the other hand, when the load exceeds a predetermined value, discharge of the hydraulic oil from the container to the circulation oil passage is permitted by the discharge permitting means. Therefore, when the operating oil temperature rises to the operating temperature of the opening / closing means having the lowest set temperature for performing the opening operation, the operating oil is discharged from the container by the opening operation of the opening / closing means, and the operating oil is cooled. . This prevents the viscosity of the hydraulic oil from becoming too low during a high load.

The eighth solution means embodies an application form of the fluid machine in each of the above solution means. That is, in one of the first to seventh solutions, the fluid machine is configured as a hydrostatic transmission including a hydraulic pump mechanism and a hydraulic motor mechanism in a container.

The above solutions reduce the horsepower loss of the hydrostatic transmission, improve the power transmission efficiency, and increase the output.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a case will be described in which the present invention is applied to an HST for a working vehicle such as a combine. Before describing the features of this embodiment, an outline of the HST 1 will be described.

FIG. 1 is a cross-sectional view showing the internal configuration of the HST 1, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. Also,
FIG. 3 is a diagram schematically showing an operation circuit of HST1.

As shown in FIGS. 1 and 2, HST1 is
The closed container 11 includes a housing 12 and a center section 13. The hydraulic pump mechanism 2 is housed in the upper half of the closed container 11, and the hydraulic motor mechanism 3 is housed in the lower half. The inside of the closed container 11 is filled with hydraulic oil, and each of the mechanisms 2 and 3 is immersed in the hydraulic oil.

The hydraulic pump mechanism 2 includes a center section 1
3, a valve plate 21 in contact with the inner side surface, a plunger block 22 as a rotating body which is slidably and rotatably contacted with the valve plate 21, and an amount of oil discharged from the hydraulic pump mechanism 2 is adjusted. The movable swash plate 23 for performing the operation is provided.

As shown in FIG. 2, a plurality of hydraulic ports 21a and 21b are formed in the valve plate 21. On the other hand, in the center section 13, two oil passages 1 are provided.
3a and 13b are formed. Each hydraulic port 21
A part 21a of the a and 21b communicates with one oil passage 13a in the center section 13, and the other hydraulic port 21b communicates with the other oil passage 13b in the center section 13 (the oil passages 13a and 13b). Is shown by a virtual line in FIG. 2).

A plurality of plunger holes 22a are formed in the plunger block 22 so as to surround the center axis of the plunger block 22, and a plunger 24 reciprocates in each plunger hole 22a. It is freely inserted.

The movable swash plate 23 is disposed so as to face the distal end of the plunger 24. The plungers 24 have their distal ends in contact with the movable swash plate 23 via a thrust plate 25. I have.

The hydraulic pump mechanism 2 has an input shaft 26 extending in the horizontal direction and passing through the housing 12 and the center section 13. The input shaft 26 is provided at the center of the plunger block 22 and the movable swash plate 23.
The openings 22b and 23a through which are inserted are formed. The input shaft 26 is rotatably supported by the housing 12 and the center section 13 via bearings B and B, and is engaged with the plunger block 22 by spline fitting. That is, the plunger block 22 is rotationally and integrally engaged with the input shaft 26. One end (the right end in FIG. 1) of the input shaft 26 is configured to transmit a driving force of an engine (not shown). On the other hand, input shaft 2
6 is the center section 1 (the left end in FIG. 1).
3 and is connected to a charge pump 4 mounted on the outer surface of the center section 13. That is, the driving force of the engine input from the input shaft 26 is transmitted not only to the hydraulic pump mechanism 2 but also to the charge pump 4 so as to drive the charge pump 4.

The tilt angle of the movable swash plate 23 can be adjusted by a control arm (not shown) (FIG. 1 shows a state where the movable swash plate 23 is not tilted (tilt angle 0 °)). By adjusting the inclination angle, it is possible to adjust the amount of oil discharged from the hydraulic pump mechanism 2 and to switch between the high-pressure side and the low-pressure side of each of the hydraulic ports 21a and 21b. When the plunger block 22 rotates with the movable swash plate 23 inclined, the plunger 24 reciprocates in the plunger hole 22a, and high-pressure oil is generated in some of the plunger holes 22a. Then, this high-pressure oil passes through a part of the hydraulic port 21a of the valve plate 21 to form one oil passage 13a formed in the center section 13.
To the hydraulic motor mechanism 3.

Next, the hydraulic motor mechanism 3 will be described. The configuration of the hydraulic motor mechanism 3 is substantially the same as that of the hydraulic pump mechanism 2. That is, it includes a valve plate 31 in contact with the inner surface of the center section 13, a plunger block 32 as a rotating body which is slidably contacted with the valve plate 31, and a swash plate 33. The swash plate 33 of the hydraulic motor mechanism 3 is a fixed swash plate 33 having a fixed inclination angle. The configurations of the valve plate 31, the plunger block 32, and the plunger 34 are the same as those of the hydraulic pump mechanism 2, and the description is omitted here.

The hydraulic motor mechanism 3 has an output shaft 36, which is rotatably supported by the housing 12 and the center section 13 via bearings B and B, and which is fitted by a spline. It is engaged with the block 32. That is, the plunger block 32 is rotationally and integrally engaged with the output shaft 36.

With the above configuration, the hydraulic pump mechanism 2
, The plunger 34 of the hydraulic motor mechanism 3 to which the high-pressure oil is supplied presses the fixed swash plate 33, and the plunger 34 slides on the fixed swash plate 33 due to the reaction force. The output shaft 36 rotates.

Next, the operation circuit of the HST 1 will be described. As shown in FIG. 3, the suction side of the charge pump 4 is connected to an oil tank 14. This charge pump 4
A strainer 15 is provided at an upstream end of the suction line, and the oil purified by the strainer 15 is supplied to the charge pump 4. Charge pump 4
Is provided with an oil filter 16 on the discharge side. The oil purified by the oil filter 16 is branched into two systems.
Can be supplied to the oil passages 13a and 13b, and the other can be supplied to the inside of the closed container 11 via the low-pressure relief valve 18. The inside of the closed container 11 and the oil passages 13a and 13b of the center section 13 are communicated via a high-pressure relief valve 19. A collection pipe 5 forming a discharge path between the closed container 11 and the oil tank 14 is provided.
The recovery pipe 5 is connected to an oil cooler 51.
Is provided. The upstream end of the collection pipe 5 is connected to a drain port 13c formed on the upper surface of the closed vessel 11. As described above, the closed vessel 11 and the oil tank 14 are connected by the pipe to form a closed circuit, thereby forming a circulating oil passage through which the working oil circulates.

With the above configuration, the operation of the HST 1 is as follows. First, the hydraulic pump mechanism 2
Then, the input shaft 26 rotates, and the hydraulic pump mechanism 2 performs a predetermined pump operation. That is, the plunger block 22 rotates with the rotation of the input shaft 26, and the plunger 24 reciprocates in the plunger block 22 according to the inclination angle of the movable swash plate 23. As a result, high-pressure oil is discharged from a predetermined hydraulic port 21 a of the valve plate 21 toward one oil path 13 a of the center section 13. This high-pressure oil acts on some plungers 34 from one oil passage 13a through some hydraulic ports 31a of the valve plate 31 of the hydraulic motor mechanism 3. By the action of the hydraulic pressure, the plunger block 32 of the hydraulic motor mechanism 3 rotates, and accordingly, the output shaft 36 rotates. In the other hydraulic port 31b, the hydraulic motor mechanism 3 sends the hydraulic pump mechanism 2
The engine driving force is transmitted to the output shaft 36 while the oil circulates between the two mechanisms 2 and 3.

Further, if the inclination angle of the movable swash plate 23 is changed, the amount of oil discharged from the hydraulic pump mechanism 2 is changed, whereby the rotation speed of the output shaft 36 can be changed. Also,
If the inclination direction of the movable swash plate 23 is changed, it is possible to switch between the high pressure side and the low pressure side of each of the hydraulic ports 21a and 21b of the valve plate 21, thereby switching the output shaft 36 between normal rotation and reverse rotation. Further, when the inclination angle of the movable swash plate 23 is set to 0 ° (neutral position shown in FIG. 1), the reciprocation of the plunger 24 is not performed, and no high pressure is generated from the hydraulic pump mechanism 2 and the rotation of the output shaft 36 is stopped. Stop. In other words, while the HST 1 is operating, the output shaft 3
6 can be put into a stopped state.

In such an operation, if oil leaks in the circuit, oil is supplied from the charge pump 4 into the circuit to compensate for the loss. In this supply operation, the oil pumped from the oil tank 14 to the charge pump 4 is purified by the oil filter 16 and then supplied into the circuit from the check valve 17.

Oil (hydraulic oil) circulates between the sealed container 11 and the oil tank 14. That is, part of the oil taken out of the oil tank 14 and passed through the charge pump 4 and the oil filter 16 is supplied to the low-pressure relief valve 1.
After that, it is supplied to the closed container 11. On the other hand, the hydraulic oil in the closed container 11 is taken out from the recovery pipe 5, cooled by the oil cooler 51, and then recovered in the oil tank 14.

With the above operation, the rotational driving force of the engine is continuously changed by the HST 1 and output to the output shaft 36.

Description of Hydraulic Oil Temperature Adjustment Structure Next, a description will be given of a structure for adjusting the hydraulic oil temperature, which is a feature of the present embodiment applied to the HST 1 configured as described above. There are various forms of this hydraulic oil temperature adjustment structure. Hereinafter, each embodiment will be described individually.

<First Embodiment> In this embodiment, a cooling water flow path is formed adjacent to the closed vessel 11, and the working oil in the closed vessel 11 is cooled by the cooling water flowing through the cooling water flow path. It is.

Specifically, as shown in FIG. 4, a flange-like projection 61 extending outward is formed on the side wall of the housing 12, and a flat lid 62 is attached over the projection 61. . Thereby, the cooling water flow path 6 is formed between the outer surface of the housing 12 and the lid 62. Also,
A plurality of radiating fins 63 are provided on the outer surface of the housing 12 facing the cooling water flow path 6 in order to enhance heat radiation.

The lid 62 is formed with an inlet 62a and an outlet 62b, respectively.
A cooling water pipe 64 that forms a cooling water flow path is connected to the outlet 62b. The cooling water pipe 64 is connected to the cooling water flow path of the engine E, and a part of the cooling water cooled by the radiator R is supplied to the cooling water flow path 6.

The cooling water pipe 64 is provided with an electromagnetic valve 65 as a switching means. By opening and closing the electromagnetic valve 65, supply and non-supply of the cooling water to the cooling water flow path 6 are switched. It has become.

The HST 1 further includes a pressure sensor PS for detecting a circuit pressure on the high pressure side (for example, a pressure in the oil passages 13a and 13b). The circuit pressure signal detected by the pressure sensor PS is transmitted to a controller C as a control means for controlling the operation of the HST1, and the controller C
The solenoid valve 65 is opened only when the circuit pressure detected by the pressure sensor PS reaches a predetermined value (for example, 25 MPa) or more, and the cooling water flows through the cooling water flow path 6. Thus, the cooling means according to the present invention is constituted.

Next, the operation of cooling the hydraulic oil according to the above configuration will be described. When the HST 1 is driven, if the circuit pressure detected by the pressure sensor PS is equal to or lower than a predetermined value (at a low load), the electromagnetic valve 65 is closed, and the cooling water is not supplied to the cooling water flow path 6. For this reason, the temperature of the hydraulic oil in the sealed container 11 increases quickly, and the viscosity thereof decreases. Therefore, the resistance of the mechanisms 2 and 3 to the rotation of the plunger blocks 22 and 32 (resistance due to the presence of hydraulic oil) is reduced, and the loss horsepower is reduced.

On the other hand, when the circuit pressure detected by the pressure sensor PS becomes a predetermined value or more (at high load), the solenoid valve 65 is opened, and a part of the cooling water cooled by the radiator R is supplied to the cooling water pipe. The cooling water is supplied to the cooling water flow path 6 through 64. Thereby, the cooling water circulates between the cooling water flow path 6 and the radiator R, and the hydraulic oil in the closed casing 11 is cooled, and the temperature rise is suppressed. As a result, it is possible to prevent the viscosity of the hydraulic oil from being excessively reduced, not only to ensure the lubricating performance of each of the mechanisms 2 and 3 well, but also to reduce the amount of leakage of the hydraulic oil from each part, thereby reducing the loss. The loss horsepower required for replenishment (power for refueling by the charge pump 4) can be reduced.

As described above, in the present embodiment, the cooling state of the hydraulic oil in the closed casing 11 is switched according to the circuit pressure of the HST 1 and the hydraulic oil temperature is set to be suitable for the circuit pressure to reduce the loss horsepower. Can be. Due to this reduction in loss horsepower, H
The power transmission efficiency of ST1 is improved, and higher output can be achieved.

Further, since the cooling water flow path 6 is formed adjacent to the outer surface of the closed vessel 11, the space required for forming the cooling water flow path 6 can be small. For this reason,
The power transmission efficiency can be improved without increasing the size of the HST 1.

In this embodiment, a temperature sensor for detecting the temperature of the hydraulic oil in the closed casing 11 may be provided in order to more appropriately adjust the temperature of the hydraulic oil. On this occasion,
For example, when the load is equal to or lower than a predetermined value, the hydraulic oil temperature is controlled to 50 ° C. or higher, and when the load exceeds a predetermined value, the hydraulic oil temperature is controlled to 50 ° C. or lower.
Specifically, temperature management is performed such that the hydraulic oil temperature is set to 80 ° C. when the circuit pressure is equal to or lower than a predetermined value, and the hydraulic oil temperature is set to 50 ° C. when the circuit pressure is equal to or higher than the predetermined value. When such temperature control is performed, even if the circuit pressure is equal to or lower than a predetermined value, when the hydraulic oil temperature exceeds 80 ° C., the electromagnetic valve 6
5 is opened to perform a cooling operation of the hydraulic oil, and conversely, even if the circuit pressure is equal to or higher than a predetermined value, when the hydraulic oil temperature is lower than 50 ° C., the solenoid valve 65 is closed to close the hydraulic oil temperature. The opening / closing control of the electromagnetic valve 65 is performed so as to promote the rise.

<Second Embodiment> In the first embodiment, the hydraulic oil in the closed casing 11 is cooled. In this embodiment, the working oil supplied to the closed casing 11 can be cooled in the circulation oil passage.

As shown in FIG. 5, a cooling water passage 64 connected to the radiator R is provided. Further, a heat exchanger 7 for exchanging heat between oil flowing through the supply oil passage 1 </ b> A leading from the charge pump 4 to the closed container 11 and cooling water flowing through the cooling water passage 64 is provided. In the cooling water passage 64,
An electromagnetic valve 65 is provided, and the opening and closing operation of the electromagnetic valve 65 switches between a circulation operation and a non-circulation operation of the cooling water in the cooling water flow path 64. Other configurations are the same as those of the first embodiment. Further, the opening / closing control operation of the electromagnetic valve 65 in the present embodiment is the same as that in the first embodiment described above.

In the case of this embodiment, since a special heat exchanger 7 for exchanging heat between the working oil and the cooling water is provided, high heat exchange efficiency can be obtained. Therefore, it is possible to rapidly cool the hydraulic oil, and it is possible to quickly avoid a situation in which the viscosity of the hydraulic oil becomes too low, especially under a high load, and the loss horsepower increases.

Further, in the present embodiment, when the opening and closing of the solenoid valve 65 is controlled not only by the circuit pressure of the HST 1 but also by the operating oil temperature, the temperature sensor Th is connected to the downstream end portion of the supply oil passage 1A (the closed container 11). At the entrance to the entrance (Fig. 5)
Virtual line).

<Third Embodiment> In this embodiment, the operating oil temperature is adjusted by switching the discharge amount of the operating oil from the closed container 11.

As shown in FIG. 6, outlets 81 and 82 are formed at two places on the upper surface of the sealed container 11. One outlet (left side in the figure) is a low-temperature side outlet 81 and the other outlet (right side in the figure) is a high-temperature side outlet 82. Thermostats 83, 8 as opening / closing means for switching the opening / closing of the outlets 81, 82 are provided near the outlets 81, 82.
4 are provided. Near the low-temperature side discharge port 81 is a low-temperature side thermostat 83, which is activated when the temperature of the hydraulic oil in the closed container 11 reaches a predetermined temperature (for example, 50 ° C.), and the closing rod 83a rises to reduce the low-temperature side discharge port 81. Is opened (FIG. 6 shows the opened state). The high temperature side thermostat 84 is located near the high temperature side discharge port 82 and is activated when the temperature of the hydraulic oil in the closed container 11 reaches a predetermined temperature (for example, 80 ° C.).
a rises to open the high-temperature side discharge port 82 (FIG. 6 shows a closed state).

The upstream side of the recovery pipe 5 connected to the oil cooler 51 and the oil tank 14 is branched into two branch pipes 52 and 53, which are connected to the discharge ports 81 and 82, respectively. The branch pipe 52 connected to the low temperature side discharge port 81 is provided with a solenoid valve 85 as discharge permitting means.

The HST 1 also has a pressure sensor PS for detecting the high-side circuit pressure. The circuit pressure signal detected by the pressure sensor PS is transmitted to the controller C,
The controller C opens the solenoid valve 85 only when the circuit pressure detected by the pressure sensor PS has reached a predetermined value (for example, 25 MPa) or more.

Next, the operation of cooling the hydraulic oil according to the above configuration will be described. When the HST1 is driven, the solenoid valve 85 is closed when the circuit pressure detected by the pressure sensor PS is equal to or lower than a predetermined value (at a low load). Closed container 11
When the internal temperature reaches 50 ° C, the low-temperature thermostat 83
The low temperature side discharge port 81 is opened by the operation of. However,
Since the solenoid valve 85 is closed, the operating oil in the closed container 11 is not discharged. That is, the operation of cooling the hydraulic oil by the oil cooler 51 is not performed. For this reason, it is possible to promote an increase in the operating oil temperature at the time of a low load, and it is possible to rapidly reduce the viscosity thereof. Therefore, the resistance of the mechanisms 2 and 3 to the rotation of the plunger blocks 22 and 32 (resistance due to the presence of hydraulic oil) is reduced, and the loss horsepower is reduced.

Thereafter, when the temperature of the hydraulic oil further rises and the temperature in the sealed container 11 reaches 80 ° C., the high-temperature side thermostat 84 is also operated, and the high-temperature side discharge port 82 is opened. The hydraulic oil in the closed container 11 is discharged by opening the high temperature side discharge port 82. That is, the operation of cooling the hydraulic oil by the oil cooler 51 is performed. Thereby, the closed container 1
The hydraulic oil circulating between the oil tank 1 and the oil tank 14 is cooled by the oil cooler 51, and an abnormal rise in the hydraulic oil temperature is suppressed.

On the other hand, when the circuit pressure detected by the pressure sensor PS becomes a predetermined value or more (at a high load), the solenoid valve 85 is opened. When the temperature in the closed container 11 reaches 50 ° C., the low-temperature side thermostat 83 is activated and the low-temperature side
1 opens. Thereby, the hydraulic oil in the closed casing 11 is discharged, and the operation of cooling the hydraulic oil by the oil cooler 51 is performed.

Thereafter, when the temperature of the hydraulic oil further rises and the temperature in the closed container 11 reaches 80 ° C., the high-temperature side thermostat 84 is also operated, and the high-temperature side discharge port 82 is opened. Thereby, the low-temperature side discharge port 81 and the high-temperature side discharge port 8
Hydraulic oil is discharged from both of them. As a result, the hydraulic oil is cooled by the oil cooler 51 in a state where the circulation amount of the hydraulic oil between the closed container 11 and the oil tank 14 is increased.

In this way, an increase in the hydraulic oil temperature under a high load is suppressed, and as a result, the viscosity of the hydraulic oil is prevented from being excessively reduced, and the lubricating performance of each of the mechanisms 2 and 3 is sufficiently ensured. In addition to this, the amount of hydraulic oil leaked from each part is also reduced, and the loss horsepower required to replenish the loss can be reduced.

<Experimental Example> An experiment conducted to confirm the effect of reducing the loss horsepower will be described below. In this experiment, the case where the temperature of the hydraulic oil in the sealed container 11 was always 50 ° C. and the case where the temperature of the hydraulic oil was always 80 ° C.
This was performed by measuring the input power while changing the circuit pressure (changing the load).

FIG. 7 shows the result. In this figure, the solid line shows the case where the temperature of the hydraulic oil is always 80 ° C., and the two-dot chain line shows the case where the temperature of the hydraulic oil is always 50 ° C.

As described above, the circuit pressure is relatively low (25
(MPa or less), the input power is less when the temperature of the hydraulic oil is set to 80 ° C. In other words, the loss horsepower is smaller when the hydraulic oil temperature is set higher. This is considered to be due to the low viscosity of the hydraulic oil.

On the contrary, the circuit pressure is relatively high (25 MPa).
In the above case, the input power is smaller when the temperature of the hydraulic oil is set to 50 ° C. In other words, setting the operating oil temperature lower requires less input power. It is considered that this is because, by increasing the viscosity of the hydraulic oil, the amount of leakage of the hydraulic oil from each part was reduced, and the loss horsepower required to replenish the loss could be reduced.

As described above, this experiment confirmed that the effect of reducing the loss horsepower was exhibited by adjusting the operating oil temperature in accordance with the circuit pressure.

-Other Embodiments- In the above embodiments, the case where the present invention is applied to the HST in which the hydraulic pump mechanism 2 and the hydraulic motor mechanism 3 are accommodated in one closed container 11 has been described. The present invention is not limited to this, and can also be applied to an HST in which a hydraulic pump mechanism and a hydraulic motor mechanism are housed in independent containers. Further, the present invention can be applied to other fluid machines such as a hydraulic device such as a hydraulic pump and a hydraulic motor.

In each of the above embodiments, the case where the present invention is applied to the HST 1 in which the inside of the closed vessel 11 is filled with the hydraulic oil has been described, but the present invention is not limited to this.
The present invention is also applicable to a fluid machine in which only a part of a rotating body is immersed in hydraulic oil.

[0075]

As described above, according to the present invention, the temperature of the hydraulic oil is controlled in accordance with the load acting on the rotating body of the fluid machine with respect to the fluid machine in which the rotating body rotates in the container in which the hydraulic oil is stored. Adjustment is made so that the viscosity of the working oil is reduced at low load to reduce the rotation loss of the rotating body, while the viscosity of the working oil is increased at high load to reduce the leakage amount of the working oil.
For this reason, the loss horsepower can be reduced at both a low load and a high load, and the efficiency of the fluid machine can be increased.

In the case where a cooling water flow path is formed adjacent to the outer surface of the container and the working oil is cooled by the cooling water flowing through the cooling water flow path, it is necessary to form the cooling water flow path. Since the space is small, high efficiency can be achieved without increasing the size of the fluid machine.

When a heat exchanger for exchanging heat between a circulation oil passage for circulating hydraulic oil between the container and the oil tank and a cooling water flow passage for cooling water is provided, Heat exchange efficiency can be obtained. For this reason, it is possible to rapidly cool the hydraulic oil, and it is possible to quickly avoid a situation where the viscosity of the hydraulic oil becomes too low, especially under a high load, and the horsepower loss increases.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an internal configuration of HST1.

FIG. 2 is a cross-sectional view of a position corresponding to line II-II in FIG.

FIG. 3 is a diagram schematically showing an operation circuit of the HST.

FIG. 4 is a diagram corresponding to FIG. 2 showing a first embodiment of a hydraulic oil temperature adjustment structure.

FIG. 5 is a diagram corresponding to FIG. 1 showing a second embodiment of the hydraulic oil temperature adjustment structure.

FIG. 6 is a diagram corresponding to FIG. 1 showing a third embodiment of the hydraulic oil temperature adjustment structure.

FIG. 7 is a diagram showing the results of an experiment performed to confirm the loss horsepower reduction effect.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 HST 11 Closed container 14 Oil tank 51 Oil cooler 6 Cooling water flow path 64 Cooling water pipe (cooling water flow path) 65 Solenoid valve (switching means) 7 Heat exchanger 81 Low temperature side discharge port 82 High temperature side discharge port 83 Low temperature side thermostat ( Opening / closing means) 84 High temperature side thermostat (Opening / closing means) 85 Solenoid valve (Emission permitting means)

Claims (8)

[Claims] 1. A fluid machine in which a rotating body rotates in a container in which hydraulic oil is stored, comprising a cooling means capable of cooling the hydraulic oil in the container, wherein the cooling means comprises a load acting on the rotating body. A fluid machine provided with a rotating body, wherein the fluid machine is configured to switch between a cooling state and a non-cooling state of the hydraulic oil according to the condition. 2. The fluid machine provided with a rotating body according to claim 1, wherein the cooling means performs a cooling operation of the hydraulic oil only when a load acting on the rotating body exceeds a predetermined value. Fluid machine with rotating body. 3. The fluid machine provided with a rotating body according to claim 2, wherein the cooling means controls the temperature of the hydraulic oil to 50 ° C. or more when the load acting on the rotating body is equal to or less than a predetermined value. A fluid machine equipped with a rotating body, wherein a cooling operation is performed so as to control the operating oil temperature to 50 ° C. or less when a predetermined value is exceeded. 4. A fluid machine provided with a rotating body according to claim 1, 2 or 3, wherein the cooling means comprises: a cooling water flow passage formed adjacent to an outer surface of the container; Switching means for switching between a flow state and a non-flow state; and control means for switching the switching means so that the cooling water flows through the cooling water flow path only when the load acting on the rotating body exceeds a predetermined value. A fluid machine comprising a rotating body, comprising: 5. A fluid machine in which a rotating body rotates in a container in which hydraulic oil is stored, wherein: a circulating oil passage for circulating hydraulic oil between the container and an oil tank; A heat exchanger for exchanging heat between the working oil circulating in the circulating oil passage and the cooling water flowing in the cooling water passage; and a switching unit capable of switching between a flowing state and a non-flowing state of the cooling water in the cooling water passage. And a control means for switching the switching means so that the cooling water flows through the cooling water passage only when the load acting on the rotating body exceeds a predetermined value. Fluid machinery. 6. A fluid machine in which a rotating body rotates in a container storing hydraulic oil, wherein a circulating oil passage for circulating hydraulic oil between the container and an oil cooler, and a load acting on the rotating body are predetermined. A fluid permitting means for permitting discharge of the hydraulic oil from the container to the circulation oil passage only when the value exceeds a value, the fluid machine including a rotating body. 7. A fluid machine provided with a rotating body according to claim 6, wherein the container is provided with a plurality of hydraulic oil outlets, and each hydraulic oil outlet is connected to a circulating oil passage. Along with
Opening / closing means for opening the hydraulic oil outlet only when the hydraulic oil temperature in the container reaches a predetermined temperature is provided,
While these opening / closing means have different set temperatures at which the opening operation is performed, the discharge permitting means is provided in a circulation oil passage connected to the opening / closing means having the lowest set temperature at which the opening operation is performed among the opening / closing means. A fluid machine provided with a rotating body. 8. A fluid machine including a rotating body according to claim 1, wherein the fluid machine is configured as a hydrostatic transmission including a hydraulic pump mechanism and a hydraulic motor mechanism in a container. A fluid machine having a rotating body.