Hydraulic actuator drive unit
The hydraulic actuator drive device addresses high energy consumption and temperature-dependent cooling issues by using ground contact for heat exchange, ensuring efficient and stable cooling without an electric motor, thus reducing energy use and maintaining performance across varying temperatures.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- UBE MASCH CORP LTD
- Filing Date
- 2022-12-15
- Publication Date
- 2026-07-29
AI Technical Summary
Existing hydraulic actuator cooling systems in injection molding machines face high energy consumption and reduced cooling performance during high ambient temperatures due to the use of air-cooled radiators and electric motors, which are inefficient and dependent on outside air temperature.
A hydraulic actuator drive device that utilizes a hydraulic fluid tank in direct contact with the ground or a heat conductive material, along with hydraulic fluid piping in contact with the ground or a heat conductive material, to exchange heat and maintain stable cooling without the need for an energy-consuming drive source.
The device achieves stable hydraulic fluid cooling at high ambient temperatures with reduced energy consumption by leveraging ground contact for heat exchange, eliminating the need for an electric motor-driven cooling system and maintaining consistent cooling performance.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a hydraulic actuator driving device having a function of cooling hydraulic oil of a hydraulic actuator which is a driving source of an injection molding machine, for example.
Background Art
[0002] An injection molding machine includes a hydraulic actuator as a driving source for, for example, forward or backward movement of an injection screw and a driving source of a mold clamping device. Heat generated due to power loss is accumulated in the hydraulic oil used in the hydraulic actuator. The hydraulic actuator can achieve smooth operation when the hydraulic oil is driven at an appropriate temperature. Therefore, an injection molding machine using a hydraulic actuator is provided with a cooling device so that the temperature of the hydraulic oil does not become excessively high.
[0003] As a means for solving problems such as high running costs of a water-cooled cooling device as a cooling device for hydraulic oil, Patent Document 1 discloses a means. Patent Document 1 proposes providing an air-cooled radiator in a flow path from a hydraulic drive source of a hydraulic unit to an oil tank in an injection molding machine having a hydraulic unit, and providing a blower fan for blowing air onto the air-cooled radiator.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] According to Patent Document 1, although problems of a water-cooled cooling device can be solved, an electric motor for driving a blower fan is required, and electric energy for driving the electric motor is consumed, so it is inferior in terms of energy saving. Further, since outside air becomes a cooling medium of the air-cooled radiator, cooling performance deteriorates in summer when the outside air is hot.
[0006] Therefore, the present invention aims to provide a hydraulic actuator device that consumes less energy and can maintain cooling performance even at high ambient temperatures. [Means for solving the problem]
[0007] The hydraulic actuator drive device of the present invention includes a hydraulic fluid tank for storing hydraulic fluid, A hydraulic actuator driven by hydraulic fluid, A hydraulic fluid piping system through which hydraulic fluid flows between the hydraulic fluid tank and the hydraulic actuator, A lubrication pump that draws up the hydraulic fluid stored in the hydraulic fluid tank and supplies it to the hydraulic actuator via the hydraulic fluid piping, It is equipped with a cooling mechanism that cools the hydraulic fluid by exchanging heat between the hydraulic fluid and the ground.
[0008] The cooling mechanism is preferably configured such that the hydraulic oil tank is in direct contact with the ground or in contact with a heat conductive material. The cooling mechanism is preferably configured such that the hydraulic fluid piping is in direct contact with the ground or in contact with a heat conductive material. In the components of the cooling mechanism, preferably, a portion of the hydraulic fluid piping is made flattened.
[0009] The hydraulic fluid tank preferably includes a plurality of first heat transfer fins that extend from the floor of the hydraulic fluid tank and are in contact with the stored hydraulic fluid. The hydraulic oil tank preferably includes a plurality of second heat transfer fins that extend from the bottom surface of the hydraulic oil tank and are embedded in the ground. Preferably, the cooling mechanism has a flattened portion of the first hydraulic fluid piping. Preferably, the cooling mechanism includes a third heat transfer fin embedded in the ground in the hydraulic oil piping. [Effects of the Invention]
[0010] According to the actuator drive device of the present invention, the hydraulic fluid tank is in contact with the ground, and stable cooling of the hydraulic fluid is possible even when the ambient temperature is high. Moreover, since the actuator drive device does not require a drive source that consumes energy such as electricity to cool the hydraulic fluid, energy consumption can be reduced. [Brief explanation of the drawing]
[0011] [Figure 1] This is a diagram showing a hydraulic actuator drive device according to the first embodiment. [Figure 2] This figure shows a hydraulic actuator drive device according to the second embodiment. [Figure 3] The image shows a modified hydraulic actuator drive device according to the second embodiment, where (a) is the overall configuration, (b) is a diagram showing how the hydraulic fluid flows inside the flattened pipe section, and (c) is a diagram showing the external appearance of the flattened pipe section. [Figure 4] This figure shows an example of heat transfer fins installed in a hydraulic oil tank. [Figure 5] This figure shows an example of heat transfer fins installed in hydraulic fluid piping. [Modes for carrying out the invention]
[0012] Embodiments of the present invention will be described below with reference to the attached drawings. [First Embodiment: Figure 1] Referring to Figure 1, the hydraulic actuator drive device 1 according to the first embodiment will be described. The hydraulic actuator drive unit 1 includes a mechanism for cooling the hydraulic fluid HO of a hydraulic actuator 50, for example, that is installed in an injection molding machine. This cooling mechanism includes the ground G as one of its elements. The example hydraulic actuator 50 includes a cylinder 51 having an internal operating region 52, a piston 53 that moves forward (A) or backward (R) within the operating region 52, and a piston rod 55 that supports the piston 53 at one end.
[0013] The operating region 52 is divided into a first operating region 52A and a second operating region 52B, with the piston 53 as the dividing line. As the piston 53 moves forward (A) or backward (R), the volume of the first operating region 52A and the second operating region 52B increases and decreases. The cylinder 51 is provided with a first supply / discharge port 57A and a second supply / discharge port 57B through which hydraulic fluid HO is supplied and discharged. When the piston 53 moves forward (A), hydraulic fluid HO is supplied from the first supply / discharge port 57A and discharged from the second supply / discharge port 57B. When the piston 53 moves backward (R), hydraulic fluid HO is supplied from the second supply / discharge port 57B and discharged from the first supply / discharge port 57A.
[0014] The hydraulic actuator drive unit 1 includes a hydraulic oil tank 11 for storing hydraulic oil HO, a first hydraulic oil pipe 13 connecting the hydraulic oil tank 11 to the first supply and discharge port 57A, and a second hydraulic oil pipe 15 connecting the hydraulic oil tank 11 to the second supply and discharge port 57B. The first hydraulic oil pipe 13 consists of a first-first control pipe 13A connected to the side of the hydraulic oil tank 11 and a first-second control pipe 13B connected to the first supply and discharge port 57A. The second hydraulic oil pipe 15 consists of a second-first control pipe 15A connected to the hydraulic oil tank 11 and a second-second control pipe 15B connected to the second supply and discharge port 57B. A flow path switching valve 17 is provided between the first primary pipe 13A and the first secondary primary pipe 13B, and between the second primary pipe 15A and the second secondary primary pipe 15B. The flow path switching valve 17 switches the flow path when the piston 53 moves forward (A) and when the piston 53 moves backward (R). FIG. 1 shows the state when the piston 53 moves backward (R). The hydraulic oil HO flowing through the second primary pipe 15A passes through the first valve 17A of the flow path switching valve 17 and flows through the second secondary primary pipe 15B, and reaches the second operation region 52B through the second supply / discharge port 57B. Although not shown, when the piston 53 moves forward (A), the flow path switching valve 17 is switched to the second valve 17B, and the hydraulic oil HO flowing through the second primary pipe 15A passes through the second valve 17B of the flow path switching valve 17 and flows through the first secondary primary pipe 13B, and reaches the first operation region 52A through the first supply / discharge port 57A. As described above, the hydraulic oil HO circulates between the hydraulic oil tank 11 and the hydraulic actuator 50 through the hydraulic oil pipes combining the first hydraulic oil pipe 13 and the second hydraulic oil pipe 15. When the piston 53 is stopped without moving forward (A) or backward (R), the hydraulic oil HO in the hydraulic oil tank 11, the first hydraulic oil pipe 13, and the second hydraulic oil pipe 15 stagnates without flowing.
[0015] The hydraulic actuator driving device 1 includes an oil supply pump 19 provided in the middle of the second primary pipe 15A, and an electric motor 21 that drives the oil supply pump 19. By driving the oil supply pump 19 with the electric motor 21, the hydraulic oil HO is pumped up from the hydraulic oil tank 11 and supplied to the first operation region 52A or the second operation region 52B through the second hydraulic oil pipe 15 or the first hydraulic oil pipe 13. The hydraulic actuator driving device 1 includes an electric motor 21 for driving the oil supply pump 19, and the electric motor 21 consumes electrical energy. However, the electric motor 21 is provided for driving the hydraulic actuator 50, and is not for cooling the hydraulic oil HO. That is, the hydraulic actuator driving device 1 does not include a dedicated drive source for cooling the hydraulic oil HO.
[0016] The hydraulic actuator driving device 1 has an operating oil tank 11 placed on the ground GS, and the operating oil HO stored in the operating oil tank 11 can exchange heat with the ground GS. That is, the operating oil tank 11 and the ground GS constitute an example of the cooling mechanism in this embodiment. The bottom surface 11A of the operating oil tank 11 and the ground GS may be in direct contact, or a heat conductive material 23 may be interposed between the bottom surface 11A and the ground GS.
[0017] This ground GS is assumed to be indoors, such as in a factory building. For example, an injection molding machine is installed indoors, and especially in summer when the temperature is high, the indoors is often air-conditioned for the labor hygiene management of workers. Naturally, the temperature of the ground GS and the underground GI is much lower than the air temperature. In particular, the temperature of the underground is hardly affected by the outside air temperature and remains almost the same throughout the year. Therefore, the temperature difference between the operating oil HO and the ground GS fluctuates little throughout the year, and the cooling performance is stable throughout the year. That is, by simply contacting the operating oil tank 11 with the ground GS, the operating oil HO stored in the operating oil tank 11 can be stably cooled. Moreover, it does not require the energy to blow cold air and has high energy efficiency. In this embodiment, the ground G is collectively referred to as the ground including the ground GS and the underground GI.
[0018] The floor of the factory building where the injection molding machine is placed may be composed of a base material such as concrete, asphalt, or iron plate. In addition to the ground GS made of soil, the floors made of these base materials also correspond to the ground GS, and their temperature is much lower than the outside air temperature. Therefore, the ground GS in the present invention has the meaning of including the surface of the floor made of concrete or the like. The operating oil tank 11 can be placed on the ground GS, or a part or all of it can be buried in the underground GI.
[0019] The hydraulic oil tank 11 is preferably made of a material with high thermal conductivity in order to quickly transfer the heat of the hydraulic oil HO to the ground G, and is typically made of metallic materials such as iron (Fe), copper (Cu), and aluminum (Al). The thermal conductivity (W / (m·K)) of these metallic materials is as follows. The thermal conductivity of the air in contact with the hydraulic oil tank 11, and of soil and concrete, which are typical examples of the ground GS, are also shown. The hydraulic oil tank 11 can be made entirely of the same material, or it can be made of different materials. For example, the part in contact with the ground GS can be made of a material with high thermal conductivity, and the other parts can be made of a material with low thermal conductivity. Fe:80, Cu:398, Al:237 Air: 0.025, Soil: 1.0, Concrete: 1.6
[0020] A heat conductive material 23 can be interposed between the hydraulic oil tank 11 and the ground GS. The heat conductive material 23 can increase the heat dissipation from the hydraulic oil tank 11 to the ground GS. When placing the hydraulic oil tank 11 on a leveled ground surface GS, even if the ground surface GS is level, minute undulations and irregularities remain on its surface. In such cases, the hydraulic oil tank 11 and the ground surface GS may only come into contact at the tops of these minute undulations, potentially increasing the contact thermal resistance. However, in this case, it is difficult to ensure that the bottom surface 11A of the hydraulic oil tank 11 and the ground surface GS are in complete contact without any gaps. Minor undulations may exist not only on the ground surface GS but also on the bottom surface 11A of the hydraulic oil tank 11. Therefore, by interposing a thermal conductive material 23, the gaps are filled, improving the degree of contact between the hydraulic oil tank 11 and the ground surface GS. This increases the heat dissipation from the hydraulic oil tank 11 to the ground surface GS. At this time, it is most preferable to tightly adhere the thermal conductive material 23 to both the hydraulic oil tank 11 and the ground surface GS in order to enable heat transfer across the entire surface area, including the minute undulations on the ground surface GS and the bottom surface 11A of the hydraulic oil tank 11.
[0021] Furthermore, injection molding machines generally perform reciprocating motion in the longitudinal direction due to the opening and closing of the mold clamping device and the forward and backward movement of the injection device. If the mounting and fixing state of the injection molding machine body loosens due to this reciprocating motion, displacement may occur at the fixing point. However, by bringing the hydraulic oil tank 11, located at the bottom of the injection molding machine, into contact with the foundation via a heat conductive material, frictional force is generated at the contact point, allowing the heat conductive material 23 to act as a displacement prevention material. Thus, it can also be used as a displacement prevention member at the point where loosening occurs in the fixing. In addition, if the hydraulic oil tank 11 is placed directly on the foundation without the heat conductive material 23, or if the heat conductive material 23 is torn due to the displacement and the hydraulic oil tank 11 is exposed and comes into direct contact with the foundation, frictional heat may be generated at the contact point between the hydraulic oil tank 11 and the foundation due to the displacement. However, by using the heat conductive material 23, this frictional heat can be absorbed by the heat conductive material 23 and dissipated to the ground GS.
[0022] As the thermal conductive material 23, a material with a thermal conductivity at least higher than that of air is used, preferably a material having a thermal conductivity of 1.0 W / (m·K) or higher, and more preferably 10 W / (m·K) or higher. When this thermal conductive material 23 is laid on the ground GS, it is preferable that the material has a degree of flexibility, fluidity, or viscosity that allows it to fill the gap between the bottom surface 11A of the hydraulic oil tank 11 and the uneven ground GS. For this reason, polymer materials with elasticity and tackiness that effectively work for adhesion, such as resins and rubber, are effective. As an example, adhesives and sheet materials containing a high thermal conductivity filler, mainly composed of silicone, are used, as silicone has superior heat resistance, cold resistance, electrical insulation, and chemical stability compared to other organic polymers, and also has high wettability to fillers (the property of being able to properly wet thermally conductive fillers). High thermal conductivity fillers can include inorganic powders with high thermal conductivity, such as aluminum oxide (Al2O3), zinc oxide (ZnO), aluminum nitride (AlN), boron nitride (BN), and titanium oxide (TiN), which are types of ceramics, as well as metal powders such as aluminum, silver, and copper. Silicone-based materials generally have a thermal conductivity in the range of 1.0 to 8.0 W / (m·K). High thermal conductivity types exceeding 10 W / (m·K) are also used for special applications. After filling the gap between the bottom surface 11A and the uneven ground GS, the material may harden and lose its fluidity and viscosity. The thermal conductive material 23 may be composed of a single material or a composite material. For example, similar to the silicone-based thermal conductive material mentioned above, a composite material can be used in which carbon fibers or metal powders with higher thermal conductivity than the matrix are dispersed in a matrix made of resin (including non-silicone types) or rubber.
[0023] Incidentally, the thickness of the thermal conductive material 23 has the same effect on thermal resistance as its thermal conductivity. Therefore, when selecting the thermal conductive material 23, simply using a material with high thermal conductivity may not yield the desired low thermal resistance. For this reason, a thin thermal conductive material 23 with a thickness of 10 mm or less is preferable, and more preferably with a thickness of 5 mm or less. In particular, a sheet-like thermal conductive material 23 with a thickness of 5 mm or less has low thermal resistance and high flexibility, making it easy to handle during installation and allowing for quick installation. Therefore, it is effective in preventing the inclusion of foreign matter that hinders heat transfer at the interface between the ground GS and the thermal conductive material 23, and at the interface between the thermal conductive material 23 and the bottom surface 11A of the tank 11. Furthermore, if high thermal conductivity cannot be obtained by using only the sheet-like thermal conductive material 23 because it cannot fill in fine irregularities, high thermal conductivity can be obtained by interposing a thermal conductive material that has not only higher thermal conductivity than air but is also a paste-like, fluid material such as grease or clay, in addition to or instead of the sheet-like thermal conductive material, to fill in the fine irregularities at the interface. In this case, even if the material is normally intended for ground gas systems, it may be used as a thermal conductive material if it has a lower thermal conductivity than air, can fill in irregularities in paste form, and has a thickness of 10 mm or less, more preferably 5 mm or less, as it can be expected to have low thermal resistance.
[0024] [Effects of the First Embodiment] As explained above, with the hydraulic actuator drive unit 1, the hydraulic fluid tank 11 is in contact with the ground GS, enabling stable cooling of the hydraulic fluid HO. Moreover, the hydraulic actuator drive unit 1 does not require a dedicated drive source for cooling the hydraulic fluid HO, thus offering high energy efficiency.
[0025] [Second Embodiment: Figure 2] Next, with reference to Figure 2, the hydraulic actuator drive device 2 according to the second embodiment will be described. The hydraulic actuator drive unit 2 has elements in common with the hydraulic actuator drive unit 1. Therefore, in the following description, elements common with the hydraulic actuator drive unit 1 will be given the same reference numerals as those in the hydraulic actuator drive unit 1, and the hydraulic actuator drive unit 2 will be described focusing on the differences from the hydraulic actuator drive unit 1.
[0026] In addition to exchanging heat between the hydraulic fluid HO and the ground GS in the hydraulic fluid tank 11, the hydraulic fluid HO and the ground GI in the first-1 control pipe 13A also exchange heat. In other words, the hydraulic actuator drive device 2 is equipped with two heat exchange mechanisms for cooling the hydraulic fluid HO.
[0027] In the hydraulic actuator drive unit 2, a portion of the first-first control pipe 13A is preferably buried in the underground GI. Since the underground GI is at a lower temperature than the heat-generating hydraulic oil HO, heat exchange occurs between the hydraulic oil HO flowing inside and the underground GI in the buried heat exchange portion HE of the first-first control pipe 13A, and the hydraulic oil HO is cooled. In a preferred configuration, the heat exchange portion HE of the first-first control pipe 13A buried in the underground GI is surrounded by a heat conductive material 23, and the heat conductive material 23 is interposed between the heat exchange portion HE and the underground GI.
[0028] [Effects of hydraulic actuator drive device 2] The hydraulic actuator drive unit 2 constitutes a heat exchange section HE by burying the first-first control pipe 13A, which serves as the return pipe for the hydraulic fluid HO from the hydraulic actuator 50 to the hydraulic fluid tank 11, in the ground GI. The first-first control pipe 13A serves as the flow path for the hydraulic fluid HO to be cooled, and its cross-sectional area can be reduced. By reducing the cross-sectional area of the flow path, the distance between the first-first control pipe 13A and the center of the flow path is shortened, making it easier to transfer heat from the inside of the hydraulic fluid HO, which is furthest from the surface of the first-first control pipe 13A and has the hardest heat dissipation, to the first-first control pipe 13A. Therefore, the distance between the hydraulic fluid HO flowing or stagnating in the first-first control pipe 13A and the ground GI can be shortened, resulting in high efficiency of heat exchange between the hydraulic fluid HO and the ground GI, and effectively cooling the entire hydraulic fluid HO. Furthermore, a small cross-sectional area of the flow path also means that the surface area per unit volume (cooling area) of the hydraulic fluid HO inside the first-first control pipe 13A can be increased.
[0029] The hydraulic actuator drive unit 2 has higher cooling performance than the hydraulic actuator drive unit 1 because it cools the hydraulic fluid HO between the ground GS and the first-to-second control pipe 13B and the hydraulic fluid tank 11 by heat exchange.
[0030] In the above example, a more preferred configuration was shown in which a part of the 1-1 control pipe 13A (heat exchange portion HE) is buried in the ground GI. However, it may also be in contact with the ground GS, or in contact with the ground GS via the heat conductive material 23. A modified example of the hydraulic actuator drive device 2 in contact with the ground GS, the hydraulic actuator drive device 3, will be described with reference to Figure 3.
[0031] As shown in Figure 3(a), the hydraulic actuator drive unit 3 has a flattened pipe section 14 located in the middle of the first-first control pipe 13A, and this flattened pipe section 14 is in contact with the ground GS via a heat conductive material 23, for example. The flattened pipe section 14 has a flattened shape that expands in the width direction W when viewed from above, and is closed to the outside except for the connection part with the first-first control pipe 13A. As shown in Figure 3(b), the flattened pipe section 14 is connected to the first-first control pipe 13A at an upstream connection part 14A, and also connected to the first-first control pipe 13A at a downstream connection part 14B. The space between the upstream connection part 14A and the downstream connection part 14B forms the flattened pipe body 14C. The hydraulic oil HO flowing in from the upstream connection part 14A undergoes heat exchange with the ground GS as it passes through the flattened pipe body 14C, and is then returned to the hydraulic oil tank 11 through the downstream connection part 14B.
[0032] As shown in Figures 3(b) and 3(c), the flattened pipe body 14C has a flow path 14F that is considerably wider in the width direction W than the upstream connection section 14A and the downstream connection section 14B. The dimension of the flow path 14F in the thickness direction T is equivalent to the pipe diameter of the 1-1 governing pipe 13A excluding the flattened pipe section 14. The hydraulic fluid HO flowing in from the upstream connection 14A spreads out in the width direction W when it enters the flattened pipe body 14C. Therefore, in the hydraulic actuator drive device 3, the distance from the cooling surface, the ground GS, to the hydraulic fluid HO is short, and the hydraulic fluid HO flowing through the flattened pipe body 14C exchanges heat with the ground GS over a wide area, so the hydraulic fluid HO can be cooled efficiently.
[0033] In addition to the above, the configurations listed in the above embodiments can be selected or modified as appropriate, as long as they do not deviate from the spirit of the present invention. [Methods for improving heat dissipation: Figures 4 and 5] For example, as shown in Figure 4, the hydraulic oil tank 11 can be provided with fins to improve heat dissipation from the hydraulic oil HO to the hydraulic oil tank 11, and also to improve heat dissipation from the hydraulic oil tank 11 to the ground GI.
[0034] Figure 4(a) shows an example in which a plurality of first heat transfer fins 24 are provided on the hydraulic oil tank 11 to improve heat dissipation from the hydraulic oil HO to the hydraulic oil tank 11. The first heat transfer fins 24 rise from the floor surface 11B of the hydraulic oil tank 11, and the heat transfer surface 24A is provided in the direction of flow of the hydraulic oil HO. This increases the heat transfer area between the hydraulic oil HO and the hydraulic oil tank 11. While the hydraulic oil HO is stored in the hydraulic oil tank 11 and during its flow, the hydraulic oil HO comes into contact with the floor surface 11B and side walls 11C of the hydraulic oil tank 11, as well as with the heat transfer surface 24A of the first heat transfer fins 24. This increases the amount of heat transferred from the hydraulic oil HO to the hydraulic oil tank 11, improving the cooling performance of the hydraulic oil HO. This hydraulic oil tank 11 has a first port 11D and a second port 11E on its side wall 11C, with the first-to-first control pipe 13A connected to the first port 11D and the second-to-first control pipe 15A connected to the second port 11E.
[0035] Figure 4(b) shows an example in which multiple second heat transfer fins 25 are provided on the hydraulic oil tank 11 to improve heat dissipation from the hydraulic oil tank 11 to the underground GI. The second heat transfer fins 25 protrude from the bottom surface 11A of the hydraulic oil tank 11, and the heat transfer surface 25A is provided in the direction of flow of the hydraulic oil HO. When the second heat transfer fins 25 are inserted into the underground GI, the area in contact between the hydraulic oil tank 11 and the underground GI (heat transfer area) increases by that amount. Therefore, while the hydraulic oil HO is stored in the hydraulic oil tank 11 and during the flow process, the amount of heat transferred to the underground GI via the second heat transfer fins 25 increases in addition to the heat transferred to the bottom surface 11B of the hydraulic oil tank 11, thus improving the cooling performance of the hydraulic oil HO.
[0036] Furthermore, as shown in Figure 5, fins can be provided on the 1-1 control pipe 13A to improve heat dissipation from the hydraulic oil piping to the ground G. This increases the heat transfer area from the hydraulic oil piping to the ground G. Figure 5(a) shows an example that can be applied to the hydraulic actuator drive unit 2. In this example, multiple third heat transfer fins 26 are provided radially on the outer surface 13C of the heat exchange portion HE in the first-first control pipe 13A buried in the ground GI. The heat transfer surface 26A of each third heat transfer fin 26 is aligned with the direction of flow of the hydraulic fluid HO, indicated by the arrow. Figure 5(b) shows an example that can be applied to the hydraulic actuator drive unit 3. In this example, multiple fourth heat transfer fins 27 are provided on the bottom surface 14D of the flattened pipe body 14C. The heat transfer surface 27A of each fourth heat transfer fin 27 is provided in line with the direction of flow of the hydraulic fluid HO, indicated by the arrow. [Explanation of Symbols]
[0037] 1,2,3 Hydraulic actuator drive unit 11. Hydraulic oil tank 11A Bottom 11B Floor surface 11C side wall 11D Port 1 11E Port 2 13. First hydraulic oil piping 13A 1st-1 control pipe 13B 1st-2 control pipe 13C Outer surface 14 Flattened pipe section 14A Upstream connection 14B Downstream connection 14C Flattened Pipe Body 14D Bottom 14F channel 15. Second hydraulic oil piping 15A 2nd-1 control pipe 15B 2nd-2 control pipe 17 Flow path switching valve 19. Fuel pump 21 Electric motor 23 Thermal conductive material 24. First heat transfer fin 24A Heat transfer surface 25. Second heat transfer fin 25A Heat transfer surface 26. Third heat transfer fin 26A Heat transfer surface 27. Fourth heat transfer fin 27A Heat transfer surface 50 Hydraulic Actuators 51 Cylinder 52 Operating area 52A 1st operating area 52B 2nd operating area 53 Pistons 55 Piston Rod 57A First supply and exhaust port 57B Second supply and exhaust port HE heat exchange part HO hydraulic oil G Ground GI underground GS ground T (thickness direction) W (width direction)
Claims
1. A hydraulic oil tank for storing hydraulic fluid, A hydraulic actuator driven by the aforementioned hydraulic fluid, A hydraulic fluid piping through which the hydraulic fluid flows between the hydraulic fluid tank and the hydraulic actuator, A supply pump that pumps the hydraulic fluid stored in the hydraulic fluid tank and supplies it to the hydraulic actuator via the hydraulic fluid piping, A hydraulic actuator drive device comprising a cooling mechanism that cools the hydraulic fluid by exchanging heat between the hydraulic fluid and the ground.
2. The hydraulic actuator drive device according to claim 1, wherein the cooling mechanism is configured by the hydraulic oil tank being in direct contact with the ground or in contact with a heat conductive material.
3. The hydraulic actuator drive device according to claim 1, wherein a portion of the hydraulic fluid piping is in direct contact with the ground or in contact with a heat conductive material to constitute the cooling mechanism.
4. The hydraulic actuator drive device according to claim 3, wherein a part of the hydraulic oil piping in the part constituting the cooling mechanism is flattened.
5. The aforementioned hydraulic fluid tank is The hydraulic actuator drive device according to claim 1, further comprising a plurality of first heat transfer fins extending from the floor surface of the hydraulic fluid tank and in contact with the stored hydraulic fluid.
6. The aforementioned hydraulic fluid tank is The hydraulic actuator drive device according to claim 1, further comprising a plurality of second heat transfer fins extending from the bottom surface of the hydraulic oil tank and embedded in the ground.
7. The hydraulic actuator drive device according to claim 1, wherein the part constituting the cooling mechanism is provided with a third heat transfer fin embedded in the ground in the hydraulic oil piping.