CN113685390A - Hydraulic directional valve and hydraulic power unit with same - Google Patents

Abstract

The invention discloses a hydraulic direction valve and a hydraulic power unit with the same, wherein the hydraulic direction valve comprises a valve body, a valve core assembly and an end cover, a first oil inlet and a valve cavity which are communicated are formed in the valve body, and a first oil port is formed in the side wall of the valve body, far away from the first oil inlet; the end cover is connected to one end, far away from the first oil inlet, of the valve body in a sealing mode, and a second oil port capable of being communicated with the valve cavity is formed in the end cover; the valve core assembly is arranged in the valve cavity and can slide along the axial direction, the valve core assembly comprises a first valve core and a check valve structure arranged in the first valve core, the check valve structure can enable hydraulic oil to flow into the valve cavity in a one-way mode through a first oil inlet under the action of upward thrust of oil pressure and flow out of a first oil port, and a sealing structure is formed between the top of the first valve core and a second oil port under the action of upward thrust of the oil pressure. Compared with the traditional hydraulic power unit, the hydraulic power unit has the advantages of small volume, simple structure, high integration level, few fault points and low cost.

Description

Hydraulic directional valve and hydraulic power unit with same

Technical Field

The invention relates to the technical field of hydraulic systems, in particular to a hydraulic directional valve and a hydraulic power unit with the same.

Background

Traditional hydraulic pressure direction valve, what adopt mostly is the check valve, can only control the direction of a certain fluid passage, and its function is single, need adopt a plurality of hydraulic pressure check valves just can satisfy the functional requirement in the in-service use for the cost is higher, and the actual installation is numerous and diverse and the fault point is many.

In addition, the traditional hydraulic power unit adopts an alternating current motor, an electromagnetic directional valve and a one-way valve to control the oil flow direction, and adopts an integrated gear pump unit with poor performance. The traditional hydraulic power unit has the advantages of complex structure, more parts, poor integration, more fault points, large assembly volume and high cost.

Based on the above situation, the present invention provides a hydraulic directional valve and a hydraulic power unit having the same, which can effectively solve the above problems.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a hydraulic directional valve which is simple in structure, reasonable and compact in design, simple in pipeline, capable of improving the integration degree of hydraulic valves, reducing the number of valves and pipelines required by actual work and reducing the system cost.

Another object of the present invention is to provide a hydraulic power unit which is driven by a dc motor, employs an integrated higher gear pump unit, and provides a simplified hydraulic directional valve in a hydraulic valve block instead of a conventional electromagnetic directional valve and a check valve. Compared with the traditional hydraulic power unit, the hydraulic power unit has the advantages of small volume, simple structure, high integration level, few fault points and low cost.

In order to solve the technical problems, the invention is realized by the following technical scheme:

in one aspect, the present invention provides a hydraulic directional valve comprising:

the valve body is provided with a first oil inlet and a valve cavity which are communicated, and the side wall of the valve body far away from the first oil inlet is provided with a first oil port;

the end cover is connected to one end, far away from the first oil inlet, of the valve body in a sealing mode, and a second oil port capable of being communicated with the valve cavity is formed in the end cover; and

the valve core assembly is arranged in the valve cavity and can slide along the axial direction, the valve core assembly comprises a first valve core and a one-way valve structure arranged in the first valve core, the one-way valve structure can enable hydraulic oil to flow into the valve cavity in a one-way mode through a first oil inlet under the action of upward thrust of oil pressure and flow out of a first oil port, and a sealing structure is formed between the top of the first valve core and a second oil port under the action of upward thrust of the oil pressure; when the first oil port is filled with oil, the hydraulic oil only flows out of the second oil port.

Preferably, the check valve structure comprises a second valve core arranged in the first valve core, a first blocking object arranged at the top of the second valve core and a first spring arranged at the top of the first blocking object, the first valve core is provided with an oil through hole communicated with the valve cavity, and the second valve core is internally provided with an oil inlet channel communicated with the oil through hole; the first blocking object moves upwards under the action of upward thrust of oil pressure, so that the oil inlet channel is communicated with the oil through hole.

Preferably, the top of the first valve core is sleeved with a second spring, and the other end of the second spring abuts against the end cover; in an initial state, a gap is formed between the top of the first valve core and the second oil port under the action of the second spring.

Preferably, clearance fit is adopted between the first valve core and the valve body, and an oil groove is formed in the outer side wall of the first valve core in the circumferential direction.

Preferably, the first oil inlet has an inner diameter smaller than the valve cavity inner diameter.

Preferably, the first spring and the second spring are both conical springs.

In a second aspect, the invention further provides a hydraulic power unit of the hydraulic directional valve, the hydraulic power unit includes a motor, a hydraulic oil circuit valve block assembly, a hydraulic gear pump and an oil tank, the hydraulic oil circuit valve block assembly includes a hydraulic oil circuit valve block, a hydraulic directional valve and an overflow valve, the hydraulic directional valve and the overflow valve are arranged on the hydraulic oil circuit valve block, the motor and the oil tank are respectively integrated on two sides of the hydraulic oil circuit valve block, the hydraulic gear pump is located in the oil tank and integrated on the hydraulic oil circuit valve block, and the hydraulic gear pump is connected with an output shaft of the motor through a coupler.

Preferably, a third oil outlet of the hydraulic gear pump is communicated with a first oil inlet of the hydraulic directional valve, a first oil port of the hydraulic directional valve is respectively communicated with the overflow valve and the system oil inlet through a first oil pipe, a second oil port of the hydraulic directional valve is communicated with the oil tank through a second oil pipe, and a fourth oil outlet of the overflow valve is communicated with the second oil pipe through the third oil pipe.

Preferably, the overflow valve comprises a second plugging object, a third spring and an inner hexagonal plug screw, one end of the second plugging object can form a sealing surface with the pipe orifice of the first oil pipe, the other end of the second plugging object is abutted against the third spring, and the other end of the third spring is embedded in the inner hexagonal plug screw.

Preferably, an oil tank interface is arranged on the oil tank, and a temperature sensor is arranged on the outer wall of the oil tank below the oil tank interface.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the hydraulic directional valve is small in overall size and light in weight, the gravity of the hydraulic directional valve is far smaller than the friction force between the valve core and the inner wall of the valve body and the oil absorption force, the structure can realize the switching and opening and closing of the oil ports mainly under the action of oil pressure, and the operation is convenient and fast; the hydraulic directional valve can be used in the application process of normal installation, inversion or installation in other directions, is flexible to use, and can meet the oil inlet or oil outlet requirements under various conditions.

2. The hydraulic power unit adopts the hydraulic directional valve to replace the traditional electromagnetic directional valve and the one-way valve, is suitable for various states of oil inlet, oil return, overhigh system oil pressure and the like, and has wide application range. Compared with the traditional hydraulic power unit, the hydraulic power unit has the advantages of small volume, simple structure, high integration level, few fault points and low cost.

Drawings

FIG. 1 is a schematic view of the initial state structure of the hydraulic directional valve of the present invention;

FIG. 2 is a schematic diagram of the hydraulic directional valve of the present invention;

FIG. 3 is a state diagram of the hydraulic directional valve of the present invention in a single position;

FIG. 4 is a state diagram of the hydraulic directional valve of the present invention in the two positions;

FIG. 5 is a state diagram of the hydraulic directional valve of the present invention in three positions;

FIG. 6 is a schematic front view of the hydraulic power unit of the present invention;

FIG. 7 is a schematic diagram of the right side view of the hydraulic power unit of the present invention;

FIG. 8 is an A-A view of the hydraulic power unit of the present invention;

FIG. 9 is a B-B view of the hydraulic power unit of the present invention;

fig. 10 is a partial view at a in fig. 9.

Reference numerals: 1-a hydraulic directional valve; 2, a motor; 3-hydraulic oil circuit valve block assembly; 4-hydraulic gear pump; 5-an oil tank; 6-a coupler; 7-oil tank interface; 8-a temperature sensor; 9-a wiring harness assembly; 10-a sealing ring; 11-a valve body; 12-a first valve spool; 13-a second valve spool; 14-an end cap; 15-a first stopper; 16-a first spring; 17-a second spring; 18-a first tubing; 19-a second tubing; 20-a third tubing; 21-oil pipe plug; 31-hydraulic oil line valve block; 32-relief valves; 41-a second oil inlet; 42-a third oil outlet; 111-a first oil inlet; 112-a first oil port; 122-a valve cavity; 123-oil groove; 131-an oil inlet channel; 141-a second oil port; 321-a second stopper; 322-a third spring; 323-hexagonal socket head; 1210-oil through hole.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present invention, the following description of the preferred embodiments of the present invention is provided in conjunction with specific examples, but it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.

The present invention will be further described with reference to the following examples and drawings 1-10, but the invention is not limited thereto.

Referring to fig. 1, a hydraulic directional valve includes a valve body 11, an end cap 14, and a valve core assembly. A first oil inlet 111 and a valve cavity 122 which are communicated with each other are formed in the valve body 11, and a first oil port 112 is formed in the side wall of the valve body 11 far away from the first oil inlet 111; the end cover 14 is connected to one end of the valve body 11 far away from the first oil inlet 111 in a sealing manner, and a second oil port 141 which can be communicated with the valve cavity 122 is formed in the end cover 14; the valve core assembly is arranged in the valve cavity 122 and can slide along the axial direction, the valve core assembly comprises a first valve core 12 and a check valve structure arranged in the first valve core 12, the check valve structure can enable hydraulic oil to flow into the valve cavity 122 in a one-way mode through the first oil inlet 111 and flow out through the first oil port 112 under the action of upward thrust of oil pressure, and a sealing structure is formed between the top of the first valve core 12 and the second oil port 141 under the action of upward thrust of oil pressure.

The one-way valve structure comprises a second valve core 13 arranged in the first valve core 12, a first blocking object 15 arranged at the top of the second valve core 13 and a first spring 16 arranged at the top of the first blocking object 15, wherein the first valve core 12 is provided with an oil through hole 1210 communicated with the valve cavity 122, and the second valve core 13 is internally provided with an oil inlet passage 131 communicated with the oil through hole 1210; the first blockage 15 moves upward under the upward thrust of the oil pressure, so that the oil inlet passage 131 communicates with the oil passing hole 1210.

Specifically, the first stopper 15 is a sphere, and a sealing surface can be formed between the sphere and the top opening of the second valve core 13; the first spring 16 is a conical spring, is arranged to be large at the top and small at the bottom, the lower end of the first spring is connected with the first plugging object 15, and the upper end of the first spring is embedded in the first valve core; in the initial state, the first stopper 15 forms a sealing surface with the outlet end of the oil inlet channel 131 under the force of the first spring 16. The valve body and the first valve core are in clearance fit, and a small enough clearance is formed between the valve body inner hole diameter and the first valve core outer diameter through the dimensional tolerance fit between the valve body inner hole diameter and the first valve core outer diameter, so that the valve body can play a role in sealing a valve and can also ensure that the first valve core can slide up and down in the valve body. The outer diameter of the second valve core 13 is in interference fit with the inner hole diameter of the first valve core 12, so that the second valve core 13 cannot slide.

A plurality of oil grooves 123 are circumferentially formed in the outer side wall of the first valve core 12 along the axial direction at equal intervals, oil is filled in the oil grooves 123, and friction loss between the first valve core 12 and the valve body 11 can be reduced.

Further, in order to ensure oil return, the second oil port 141 of the end cover 14 can be smoothly opened. The second spring 17 is sleeved on the top of the first valve core, the other end of the second spring 17 abuts against the end cover 14, and the second spring 17 is a conical spring and is arranged to be large in top and small in bottom. In the initial state, a gap is formed between the top of the first valve element and the second oil port 141 under the action of the second spring 17, and the opening state is maintained.

Because the valve core assembly of the hydraulic directional valve 1 is small in overall size and light in weight, the self gravity of the valve core assembly is far smaller than the friction force between the first valve core 12 and the inner wall of the valve body 11 and the oil absorption force, the switching and opening and closing of oil ports are realized mainly by the pressure of hydraulic oil, and the three oil inlet and outlet states of the hydraulic directional valve 1 are as follows:

one bit, see fig. 2 and 3. After the pressure oil enters the valve cavity from the first oil inlet 111, because the force bearing area of the first valve core 12 is larger than that of the first plugging object 15, the first valve core 12 is pushed to move upwards, so that the second spring 17 is compressed first, the top spherical surface of the first valve core 12 is attached to the conical surface of the second oil port 141 on the end cover 14, and the second oil port 141 is closed. When the pressure reaches a certain value, the first blocking object 15 moves downwards, the first blocking object 15 compresses the first spring 16, the first blocking object 15 is separated from the top conical surface of the second valve core 13, and the hydraulic oil is discharged from the first oil port 112. The pretightening force of the first spring 16 and the pretightening force of the second spring 17 can be set according to the actual use condition, so that the top of the first valve core 12 is firstly sealed with the second oil port 141 under the same oil pressure condition.

In the case of two bits, see fig. 2 and 4. When pressure oil enters the valve cavity from the first oil port 112, under the action of the second spring 17, the top spherical surface of the first valve core 12 is separated from the conical surface of the second oil port 141 of the end cover 14, and simultaneously the pressure oil enters the inner cavity of the first valve core 12 from the circumferential oil through hole 1210 of the first valve core 12, so that the first blocking object 15 in the inner cavity of the first valve core 12 moves downwards to be tightly attached to the top conical surface of the second valve core 13 under the downward common acting force of the hydraulic oil and the first spring 16. In this position, the second port 141 is kept open, the first oil inlet 111 is closed, and the hydraulic oil is discharged from the second port 141.

Three positions, see fig. 2 and 5. When hydraulic oil enters the valve cavity from the second oil port 141, under the action of the second spring 17, the top spherical surface of the first valve core 12 is separated from the conical surface of the second oil port 141 of the end cover 14, and simultaneously, under the downward common acting force of the hydraulic oil and the first spring 16, the first plugging object 15 in the cavity of the first valve core 12 moves downward and is tightly attached to the top conical surface of the second valve core 13. In this position, the first oil port 112 remains open, the first oil inlet 111 is closed, and the hydraulic oil is discharged from the first oil port 112.

Referring to fig. 6 to 10, the hydraulic directional valve 1 is applied to a hydraulic power unit of the present invention, and the hydraulic power unit includes a motor 2, a harness assembly 9, a seal ring 10, a hydraulic oil circuit valve block assembly 3, a skeleton oil seal, a coupler 6, a hydraulic gear pump 4, an oil tank 5, a temperature sensor 8, and an oil tank interface 7. The overflow valve 32 is a safety component of the hydraulic power unit, controls the oil pressure in the device, and when the oil pressure is too high, the overflow valve 32 is opened, so that the oil pressure in the device is kept in a safety range.

The hydraulic oil path valve block assembly 3 includes a hydraulic oil path valve block 31, a hydraulic directional valve 1 installed in the hydraulic oil path valve block 31, and an overflow valve 32. The overflow valve 32 comprises a second blocking object 321, a third spring 322 and an inner hexagonal plug 323, one end of the second blocking object 321 can form a sealing surface with the nozzle of the first oil pipe 18, the other end of the second blocking object is abutted against the third spring 322, and the other end of the third spring 322 is embedded in the inner hexagonal plug 323. The second stopper 321 is a steel ball, and the hexagonal socket screw 323 seals with the hydraulic oil line valve block 31 through the seal ring 10. And after the debugging is qualified, the inner hexagonal plug 323 of the overflow valve 32 and the hydraulic valve block are riveted and fixed, so that the overflow pressure is prevented from being changed due to the rotation of the overflow valve 32 caused by vibration.

The motor 2 is a direct current motor 2, the motor 2 is installed on the left side of the hydraulic oil path valve block 31 and is connected with the hydraulic oil path valve block 31 through a bolt, an output shaft of the motor 2 is located in the hydraulic oil path valve block 31, the hydraulic gear pump 4 is connected with the right side of the hydraulic oil path valve block 31 through a bolt, and the oil tank 5 is installed on the right side of the hydraulic oil path valve block component 3 and is connected with the hydraulic oil path valve block 31 through a bolt; the hydraulic gear pump 4 is positioned in the oil tank 5 and is connected with the output shaft of the motor 2 through a coupling 6.

The second oil inlet 41 of the hydraulic gear pump 4 is located in the oil tank 5, the third oil outlet 42 of the hydraulic gear pump 4 is communicated with the first oil inlet 111 of the hydraulic directional valve 1, the first oil port 112 of the hydraulic directional valve 1 is respectively communicated with the overflow valve 32 and the system oil inlet through the first oil pipe 18, the second oil port 141 of the hydraulic directional valve 1 is communicated with the oil tank 5 through the second oil pipe 19, and the fourth oil outlet of the overflow valve 32 is communicated with the second oil pipe 19 through the third oil pipe 20. And a second oil inlet 41 and a third oil outlet 42 of the hydraulic gear pump 4 are both provided with filter screens, and the filter screens and the oil outlets are in interference fit. Adopt the design of integrating, cancel 4 protecgulums of hydraulic gear pump, directly link to each other with hydraulic pressure oil circuit valve block 31 in the middle of the 4 casings of hydraulic gear pump.

The hydraulic oil way valve block 31 adopts a steel ball as the oil pipe plug 21, so that the size of parts is reduced while the oil way sealing performance is ensured, and the cost is reduced.

The working principle of the hydraulic power unit is as follows:

when the motor 2 is started, the output shaft of the motor 2 transmits power to the hydraulic gear pump 4 through the coupler 6, the second oil inlet 41 starts to absorb oil, after the oil passes through the filter screen in the second oil inlet 41, iron particles in the oil flow from the hydraulic gear pump 4 to the first oil inlet 111 of the hydraulic directional valve 1 after being purified, and then the hydraulic oil flows from the first oil port 112 of the hydraulic directional valve 1 to the first oil pipe 18 of the hydraulic oil way valve block 31 and then enters the system from the system oil inlet. When the oil pressure in the system is too high, the hydraulic oil enters the oil inlet of the overflow valve 32 from the first oil pipe 18, then the second blocking object 321 is pushed open, and the hydraulic oil returns to the oil tank 5 from the fourth oil outlet of the overflow valve 32 through the third oil pipe 20 and the second oil pipe 19.

When the system returns oil, hydraulic oil enters the first oil pipe 18 of the hydraulic oil circuit valve block 31 from the system oil inlet, then enters the first oil port 112 of the hydraulic directional valve 1, enters the hydraulic directional valve 1, then enters the second oil pipe 19 of the hydraulic oil circuit valve block 31 from the second oil port 141 of the hydraulic directional valve 1, and then returns to the oil tank 5 through the hydraulic oil circuit valve block 31.

According to the description and the drawings of the invention, a hydraulic directional valve and a hydraulic power unit of the invention can be easily manufactured or used by those skilled in the art, and can produce the positive effects described in the invention.

Unless otherwise specified, in the present invention, if there is an orientation or positional relationship indicated by terms of "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, rather than to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, the terms describing orientation or positional relationship in the present invention are for illustrative purposes only, and should not be construed as limiting the present patent, specific meanings of the above terms can be understood by those of ordinary skill in the art in light of the specific circumstances in conjunction with the accompanying drawings. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

Unless expressly stated or limited otherwise, the terms "disposed," "connected," and "connected" are used broadly and encompass, for example, being fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.

Claims (10)

1. A hydraulic directional valve, comprising:

the valve body (11) is provided with a first oil inlet (111) and a valve cavity (122) which are communicated, and the side wall of the valve body (11) far away from the first oil inlet (111) is provided with a first oil port (112);

the end cover (14) is connected to one end, far away from the first oil inlet (111), of the valve body (11) in a sealing mode, and a second oil port (141) which can be communicated with the valve cavity (122) is formed in the end cover (14); and

the valve core assembly is arranged in the valve cavity (122) and can slide along the axial direction, the valve core assembly comprises a first valve core (12) and a one-way valve structure arranged in the first valve core (12), the one-way valve structure can enable hydraulic oil to flow into the valve cavity (122) in a one-way mode through a first oil inlet (111) under the action of upward thrust of oil pressure and flow out of a first oil port (112), and a sealing structure is formed between the top of the first valve core (12) and a second oil port (141) under the action of upward thrust of oil pressure; when the first oil port (112) is filled with oil, the hydraulic oil only flows out from the second oil port (141).

2. The hydraulic directional valve as set forth in claim 1, wherein: the check valve structure comprises a second valve core (13) arranged in the first valve core (12), a first plugging object (15) arranged at the top of the second valve core (13) and a first spring (16) arranged at the top of the first plugging object (15), wherein an oil through hole (1210) communicated with the valve cavity (122) is formed in the first valve core (12), and an oil inlet channel (131) capable of being communicated with the oil through hole (1210) is formed in the second valve core (13); the first blocking object (15) moves upwards under the action of upward thrust of oil pressure, so that the oil inlet channel (131) is communicated with the oil through hole (1210).

3. The hydraulic directional valve as set forth in claim 1, wherein: the top of the first valve core (12) is sleeved with a second spring (17), and the other end of the second spring (17) is abutted against the end cover (14); in the initial state, a gap is formed between the top of the first valve core (12) and the second oil port (141) under the action of the second spring (17).

4. The hydraulic directional valve as set forth in claim 1, wherein: the first valve core (12) is in clearance fit with the valve body (11), and an oil groove (123) is formed in the outer side wall of the first valve core (12) in the circumferential direction.

5. The hydraulic directional valve as set forth in claim 1, wherein: the inner diameter of the first oil inlet (111) is smaller than that of the valve cavity (122), and the diameter of the top of the first valve core (12) is smaller than that of the valve cavity (122).

6. The hydraulic directional valve as set forth in claim 1 or 3, wherein: the first spring (16) and the second spring (17) are both conical springs.

7. A hydraulic power unit having the hydraulic directional valve of claim 1, characterized in that: the hydraulic power unit comprises a motor (2), a hydraulic oil circuit valve block assembly (3), a hydraulic gear pump (4) and an oil tank (5), the hydraulic oil circuit valve block assembly (3) comprises a hydraulic oil circuit valve block (31), a hydraulic direction valve (1) and an overflow valve (32) are arranged on the hydraulic oil circuit valve block (31), the motor (2) and the oil tank (5) are respectively integrated on two sides of the hydraulic oil circuit valve block (31), the hydraulic gear pump (4) is located in the oil tank (5) and integrated on the hydraulic oil circuit valve block (31), and the hydraulic gear pump (4) is connected with an output shaft of the motor (2) through a coupler (6).

8. The hydraulic power unit as defined in claim 7, wherein: a third oil outlet (42) of the hydraulic gear pump (4) is communicated with a first oil inlet (111) of the hydraulic directional valve (1), a first oil port (112) of the hydraulic directional valve (1) is respectively communicated with an overflow valve (32) and a system oil inlet through a first oil pipe (18), a second oil port (141) of the hydraulic directional valve (1) is communicated with an oil tank (5) through a second oil pipe (19), and a fourth oil outlet of the overflow valve (32) is communicated with the second oil pipe (19) through a third oil pipe (20).

9. The hydraulic power unit as defined in claim 7, wherein: the overflow valve (32) comprises a second plugging object (321), a third spring (322) and an inner hexagonal screw plug (323), one end of the second plugging object (321) can form a sealing surface with the pipe orifice of the first oil pipe (18), the other end of the second plugging object is abutted against the third spring (322), and the other end of the third spring (322) is embedded in the inner hexagonal screw plug (323).

10. The hydraulic power unit as defined in claim 7, wherein: an oil tank interface (7) is arranged on the oil tank (5), and a temperature sensor (8) is arranged on the outer wall of the oil tank (5) below the oil tank interface (7).

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