Low-noise built-in hydraulic drive unit

Abstract

The present invention discloses a low-noise, integrated hydraulic drive unit and relates to the technical field of hydraulic drive units. The low-noise, integrated hydraulic drive unit comprises an oil tank, an inner tank body, and an electric motor. The inner tank body is located at least partially within the oil tank, with the side wall of the inner tank body being attached to or integrally formed with the side wall of the oil tank, and the portion of the inner tank body located outside the oil tank being provided with an opening in the inner tank body. The electric motor is arranged within the inner tank body. In the present invention, the electric motor is attached to the inner tank body, which is located within the oil tank, and noise from the electric motor is absorbed by the hydraulic oil in the oil tank, thereby significantly reducing the overall noise level of the unit.

Description

[0001] The present invention relates to the technical field of hydraulic drive units, in particular a low-noise built-in hydraulic drive unit.

[0002] In conventional hydraulic drive units, an electric motor is typically located outside an oil tank, or alternatively, the electric motor and a pump are located outside the oil tank. For example, DE 44 21 375 A1 discloses a hydraulic power unit in which the electric motor and the pump are located within an encapsulated cavity. DE 199 21 436 discloses a hydraulic power unit with a pre-pressurized tank and a pump located in a separate housing. DE 33 44 197 A1 discloses an immersion unit with a pump and a motor located in a common housing. DE 10 2015 219 091 A1 discloses a pump located in a dry interior space. DE 101 22 859 A1 discloses a hydraulic power unit in which the pump and the motor are located in a closed space.

[0003] With such an arrangement, it is not possible to minimize the noise and vibrations of the electric motor. Therefore, the machine typically generates strong vibrations and unpleasantly loud noises during operation. It is known from the prior art that a soundproof enclosure surrounding the electric motor is additionally provided, but this involves high costs and larger dimensions.

[0004] In view of the disadvantage in the prior art, the present invention is based on the objective of providing a low-noise built-in hydraulic drive unit, thereby solving the emission problem caused by the noise and strong vibrations of the electric motors in existing hydraulic drive units.

[0005] According to one aspect of the present invention, the problem is solved by a low-noise, integrated hydraulic drive unit. The hydraulic drive unit comprises an oil tank, an inner tank body, and an electric motor.

[0006] The inner tank body is located at least partially inside the oil tank, wherein the side wall of the inner tank body is attached to the side wall of the oil tank or is formed as one piece with it, and wherein the part of the inner tank body located outside the oil tank is provided with an inner tank body opening.

[0007] The electric motor is mounted inside the inner tank body.

[0008] In the low-noise, integrated hydraulic drive unit according to the present invention, the electric motor is attached to the inner tank body, which is located inside the oil tank. Any noise from the electric motor is absorbed by the hydraulic oil in the oil tank, thereby significantly reducing the overall noise generated by the system. Compared to a design with an additional soundproof enclosure surrounding the electric motor, lower overall costs are achieved by absorbing noise using the hydraulic oil already present in the oil tank.

[0009] According to the invention, a hydraulic pump is provided in the oil tank, wherein a rotating shaft of the electric motor is arranged in the oil tank by means of a sealing structure, and wherein the hydraulic pump is kinetically coupled to the rotating shaft of the electric motor. Thus, the hydraulic pump is designed such that it can be kinetically coupled to the electric motor for drawing in and draining oil, and the rotating shaft of the electric motor is arranged in the oil tank via a sealing structure, so that the electric motor does not come into direct contact with the hydraulic oil in the oil tank, thereby reducing the requirements for the electric motor and thus lowering costs.

[0010] In an embodiment not covered by the invention, a hydraulic pump is provided in the inner tank body. This pump is connected to a rotating shaft of the electric motor via a motion coupling, and its oil inlet and outlet are each located in the oil tank by means of a sealing structure. Thus, the hydraulic pump can also be located in the inner tank body, allowing the hydraulic oil in the oil tank to dampen noise from the hydraulic pump. The sealing structure positions the oil inlet and outlet of the hydraulic pump within the oil tank, preventing the electric motor from coming into direct contact with the hydraulic oil in the oil tank. This reduces the requirements for the electric motor and consequently lowers costs.

[0011] In some embodiments, the side wall of the oil tank is recessed inwards, forming the inner tank body; or the side wall of the oil tank is recessed inwards, creating a receiving cavity in which the inner tank body is at least partially located; or the side wall of the oil tank is provided with a receiving opening through which the inner tank body is at least partially located in the oil tank and which is tightly connected to the side wall of the inner tank body. Thus, three mounting options are available for the oil tank and the inner tank body. In the first embodiment, the side wall of the oil tank is recessed inwards, forming the inner tank body. In this case, no seal is necessary between the oil tank and the inner tank body. In the second embodiment, the side wall of the oil tank is recessed inwards.In the third embodiment, the side wall of the oil tank is recessed, creating a receiving cavity in which the inner tank body is arranged. In this embodiment, no seal is required between the oil tank and the inner tank body. In the third embodiment, the side wall of the oil tank is provided with a receiving opening through which the inner tank body is positioned within the oil tank. However, in this embodiment, a seal is required between the oil tank and the inner tank body.

[0012] In some embodiments, a shock-absorbing element is provided between the inner tank body and the side wall of the oil tank if the side wall of the oil tank is recessed inwards, thus forming a receiving cavity in which the inner tank body is at least partially located; or if the side wall of the oil tank is provided with a receiving opening through which the inner tank body is at least partially located in the oil tank and to which the side wall of the inner tank body is tightly connected, the tight connection being a shock-absorbing, tight connection. Thus, either a shock-absorbing element is provided or the inner tank body is attached via a shock-absorbing, tight connection, so that vibrations generated during the operation of the electric motor and the hydraulic pump can be reduced. If the shock-absorbing element is a shock-absorbing disc, it can also serve as dust protection.

[0013] In some embodiments, the inner tank opening is provided with a cover plate on the inner tank, which incorporates an air inlet and an air outlet. This cover plate is designed to serve as protection against dust and other contaminants. By providing the air inlet and outlet on the cover plate, the air exchange within the inner tank can be accelerated, and the heat dissipation from the electric motor located within the inner tank can be improved.

[0014] In some embodiments, the oil outlet of the hydraulic pump is connected to an oil pipe, one end of which is located outside the oil tank via a sealing structure. Thus, by providing the oil pipe in conjunction with the hydraulic pump, the hydraulic oil can be drawn from the oil tank.

[0015] In some embodiments, one end of the oil pipe is connected to an integrated valve assembly attached to the oil tank. Thus, by providing the integrated valve assembly, multiple controllable oil paths can be made available.

[0016] In some embodiments, an oil outlet of the integrated valve assembly is connected to a filter. This filter allows contaminants to be removed from the hydraulic oil.

[0017] In some embodiments, the oil tank is equipped with an air filter. This allows air entering the oil tank to be filtered by the air filter.

[0018] In contrast to the prior art, the low-noise, integrated hydraulic drive unit according to the present invention has its electric motor housed within the inner tank body, which is at least partially located inside the oil tank. This allows the noise from the electric motor to be absorbed or dampened by the hydraulic oil in the oil tank, thereby significantly reducing the overall noise level generated by the system. Compared to a design in which a soundproofing cover is additionally provided outside the electric motor, lower overall costs are achieved because the noise is absorbed by the hydraulic oil already present in the oil tank.

[0019] The invention will now be explained in more detail with reference to exemplary embodiments shown in the figures, wherein Fig. Figure 1 shows a sectional view of the overall structure of a low-noise built-in hydraulic drive unit according to an embodiment according to the invention; Fig. 2 an enlarged representation of detail A according to Fig. 1 shows; and Fig. Figure 3 shows a three-dimensional representation of the overall structure of the low-noise built-in hydraulic drive unit according to an embodiment according to the invention.

[0020] The invention will be discussed in more detail below with reference to the accompanying figures.

[0021] According to a first aspect of the present invention, Fig. 1 to 3 a low-noise, built-in hydraulic drive unit according to an embodiment of the present utility model. As in Fig.As shown in Figures 1 to 3, the low-noise, integrated hydraulic drive unit comprises an oil tank 100, an inner tank body 200, and an electric motor 300. The upper side wall of the oil tank 100 is recessed inwards, creating a receiving cavity.

[0022] Alternatively, the lower side wall, the left side wall, the right side wall, the front side wall, or the rear side wall of the oil tank 100 can be recessed or set back inwards, thereby forming the receiving cavity.

[0023] The inner tank body 200 is located in the receiving cavity. The side wall of the inner tank body 200 is attached to the side wall of the oil tank 100 by a bolt. Alternatively, the inner tank body 200 and the oil tank 100 can be welded together. The portion of the inner tank body 200 located outside the oil tank 100 is provided with an opening in the inner tank body.

[0024] The electric motor 300 is inserted into the inner tank body 200 through the opening in the inner tank body and secured to the inner tank body 200 by a bolt. Alternatively, the electric motor 300 can be welded to the inner tank body 200. A rotating shaft of the electric motor 300 passes sequentially through the side walls of the oil tank 100 and the inner tank body 200 and is located within the oil tank 100. The rotating shaft of the electric motor 300 is sealed to the side walls of the oil tank 100 and the inner tank body 200 by means of an electric motor sealing ring. Alternatively, the rotating shaft of the electric motor 300 can also be sealed to the side walls of the oil tank 100 and the inner tank body 200 by means of a sealed bearing or another structure, component, or device that enables the sealing of the electric motor shaft.In the present embodiment, the electric motor 300 is attached to the inner tank body 200, which is located in the oil tank 100, and the rotating shaft of the electric motor 300 is located in the oil tank 100 via a sealing structure, whereby noise from the electric motor 300 is absorbed by the hydraulic oil in the oil tank 100. Thus, the overall noise level generated by the system is significantly reduced.

[0025] Furthermore, the electric motor 300 is not in direct contact with the hydraulic oil in the oil tank 100, thus reducing the requirements for the electric motor 300 in this regard. Therefore, an electric motor 300 can be used that does not need to be sealed against the oil, which in turn contributes to reduced costs. Compared to a design in which a soundproof enclosure is additionally provided outside the electric motor, lower overall costs are achieved because all noise is absorbed by the hydraulic oil in the oil tank 100.

[0026] The side wall of the oil tank 100 is recessed inwards, thus forming the receiving cavity in which the inner tank body 200 is arranged. No seal is required between the oil tank 100 and the inner tank body 200.

[0027] The outer wall of the oil tank 100 is provided with an oil tank oil return opening 101, and several mounting brackets 102 are attached to the outer wall of the oil tank 100 by welding or are integrally formed with it. The oil tank oil return opening 101 is generally located near the bottom of the oil tank 100, and the mounting bracket 102 primarily serves to secure the oil tank 100.

[0028] Inside the oil tank 100, a hydraulic pump 400 is provided, which is connected to the rotating shaft of the electric motor 300 via a motion coupling. The hydraulic pump 400 is also mounted on the side wall of the oil tank 100 (the inner tank body 200). The hydraulic pump 400 is motion-coordinated with the electric motor 300 and serves to draw in or drain oil depending on the direction of rotation of the electric motor 300.

[0029] A shock-absorbing element 500 is provided between the inner tank body 200 and the side wall of the oil tank 100. As shown, the inner tank body 200 is bent outwards, forming a curved section 201. A shock-absorbing disc is installed between the curved section 201 and the side wall of the oil tank 100, reducing vibrations generated during the operation of the electric motor 300 and the hydraulic pump 400.

[0030] Furthermore, the shock-absorbing disc can also serve as dust protection. In addition to the shock-absorbing disc, the shock-absorbing element 500 can also be a shock-absorbing spring or another component or device for shock absorption.

[0031] The inner tank opening is provided with an inner tank cover plate 202, which includes an air inlet element 203 and an air outlet element 204. The inner tank cover plate 202 is also provided with a cable outlet 205. The inner tank cover plate 202 protects the electric motor 300 and other components inside the inner tank 200 and shields them from dust. However, after the inner tank cover plate 202 is installed, the heat dissipation of the electric motor 300 within the inner tank 200 could be impaired. By providing the air inlet element 203 and the air outlet element 204 on the inner tank cover plate, the exchange of air within the inner tank 200 is accelerated, thus improving the heat dissipation of the electric motor 300. The air inlet element 203 can be an air inlet with a dust protection grille or an air inlet with a blower and a dust protection grille.The air outlet element 204 can be an air outlet with a dust protection grille. The cable outlet 205 primarily serves for cable routing, for example for a power cable and a control cable of the electric motor 300.

[0032] The oil outlet of the hydraulic pump 400 is connected to an oil pipe 600, one end of which is positioned outside the oil tank 100 via a sealing structure. Hydraulic oil can be drawn from the oil tank 100 via the oil pipe 600 in conjunction with the hydraulic pump 400. The sealing structure can be a sealing ring or another sealing component or device.

[0033] One end of the oil pipe 600 is connected to an integrated valve assembly 700, which is attached to the oil tank 100 by welding or via a bolt. The integrated valve assembly 700 primarily serves to divide a single oil path of the oil pipe 600 into several controllable oil paths, so that these oil paths can each be connected to different hydraulic consumers in order to control different hydraulic consumers.

[0034] An oil outlet of the integrated valve group 700 is connected to a filter 800. The filter 800 primarily serves to filter out impurities from the hydraulic oil.

[0035] An air filter 900 is mounted at the top of the oil tank 700. The air filter 900 filters the air entering the oil tank 100.

[0036] In another embodiment, the side wall of the oil tank 100 is recessed inwards, forming the inner tank body 200. The oil tank 100 and the inner tank body 200 can also be designed such that the side wall of the oil tank 100 is recessed inwards, with the recessed portion of the oil tank 100 forming the inner tank body 200. In this case, no seal is required between the oil tank 100 and the inner tank body 200. That is, the oil tank 100 and the inner tank body 200 are formed as a single unit.

[0037] In another embodiment, the side wall of the oil tank 100 is provided with a receiving opening through which the inner tank body 200 can be positioned inside the oil tank 100 and to which the side wall of the inner tank body 200 is tightly connected. However, a seal is necessary between the oil tank 100 and the inner tank body 200. For sealing purposes, the side wall of the inner tank body 200 can be welded tightly to the receiving opening. Alternatively, a sealing washer and a bolt can be used for sealing. A shock-absorbing sealing washer can be selected to reduce the vibrations generated during the operation of the electric motor 300 and the hydraulic pump 400. Alternatively, in addition to using the sealing washer, the shock-absorbing element 500 can also be used to enhance the shock-absorbing function.

[0038] In another embodiment not covered by the invention, the hydraulic pump 400 is arranged in the inner tank body 200 and connected to the rotating shaft of the electric motor 300 via a motion coupling. Part of the hydraulic pump 400, or the oil inlet and outlet ends of the hydraulic pump 400, pass successively through the side walls of the oil tank 100 and the inner tank body 200, so that the oil inlet and outlet ends of the hydraulic pump 400 are located within the oil tank 100. The oil inlet and outlet ends of the hydraulic pump are tightly connected to the side walls of the oil tank 100 and the inner tank body 200 via a sealing structure. The hydraulic pump 400 can also be arranged within the inner tank body 200, so that the hydraulic oil in the oil tank 100 also absorbs noise from the hydraulic pump 400. The sealing structure can be a sealing ring or another sealing component or device.

[0039] In another embodiment, the inner tank body 200 is not provided with a curved section 201 that is bent outwards. Instead, the shock-absorbing element 500 is arranged directly between the inner tank body 200 and the side wall of the receiving cavity of the oil tank 100.

[0040] So far, only some embodiments of the present invention have been described. For those skilled in the art, various variants and further developments are possible without deviating from the basic ideas of the present invention, and these also fall within the scope of protection of the present invention. REFERENCE MARK LIST 100 oil tank 101 Oil tank oil return opening 102 mounting brackets 200 inner tank bodies 201 curved section 202 Inner tank body cover plate 203 Air intake element 204 Air outlet element 205 Cable outlet 300 electric motor 400 hydraulic pump 500 shock absorber elements 600 oil pipe 700 integrated valve group 800 filters 900 air filters

Claims

[1] Low-noise built-in hydraulic drive unit comprising: an oil tank (100); an inner tank body (200) which is located at least partially inside the oil tank (100), wherein the side wall of the inner tank body (200) is attached to the side wall of the oil tank (100) or is formed integrally with it, and wherein the part of the inner tank body (200) located outside the oil tank (100) is provided with an inner tank body opening; and an electric motor (300) which is arranged in the inner tank body (200), characterized by , that a hydraulic pump (400) is provided in the oil tank (100), wherein a rotating shaft of the electric motor (300) is at least partially arranged in the oil tank (100) by means of a sealing structure, and wherein the hydraulic pump (300) is motionally coupled to the rotating shaft of the electric motor (300). [2] Low-noise built-in hydraulic drive unit according to claim 1, characterized by, that the side wall of the oil tank (100) is recessed inwards, thus forming the inner tank body (200); or that the side wall of the oil tank (100) is recessed inwards, thereby forming a receiving cavity in which the inner tank body (200) is at least partially located; or that the side wall of the oil tank (100) is provided with a receiving opening through which the inner tank body (200) is at least partially located in the oil tank (100) and with which the side wall of the inner tank body (200) is tightly connected. [3] Low-noise built-in hydraulic drive unit according to claim 2, characterized by, that a shock-absorbing element (500) is arranged between the inner tank body (200) and the side wall of the oil tank (100) if the side wall of the oil tank (100) is recessed inwards, thereby forming a receiving cavity in which the inner tank body (200) is at least partially located; or that if the side wall of the oil tank (100) is provided with a receiving opening through which the inner tank body (200) is at least partially located in the oil tank (100) and with which the side wall of the inner tank body (200) is tightly connected, the tight connection is a shock-absorbing tight connection. [4] Low-noise built-in hydraulic drive unit according to one of claims 1 to 3, characterized by , that the inner tank body opening is provided with an inner tank body cover plate (202) on which an air inlet element (203) and an air outlet element (204) are provided. [5] Low-noise built-in hydraulic drive unit according to any one of claims 1 to 4, characterized by , that the oil outlet end of the hydraulic pump (400) is connected to an oil pipe (600) which is arranged at one end outside the oil tank (100) via a sealing structure. [6] Low-noise built-in hydraulic drive unit according to claim 5, characterized by , that one end of the oil pipe (600) is connected to an integrated valve group (700) which is attached to the oil tank (100). [7] Low-noise built-in hydraulic drive unit according to claim 6, characterized by , that an oil outlet of the integrated valve group (700) is connected to a filter (800). [8] Low-noise built-in hydraulic drive unit according to any one of claims 1 to 7, characterized by that the oil tank (100) is equipped with an air filter (900).

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