Hydraulic unit installation structure

Abstract

The present invention relates to a mounting structure of a hydraulic unit, comprising a fixed reduction box housing and a hydraulic unit, wherein a left oil pool, a right oil pool, a left oil cylinder mounting cavity and a right oil cylinder mounting cavity are arranged in the fixed reduction box housing, the left oil pool and the right oil pool are connected at the bottom, the hydraulic unit is detachably fixedly mounted on the fixed reduction box housing and is located in one of the left and right oil cylinder mounting cavities, the oil cylinder mounting cavity where the hydraulic unit is located and the oil pool on the lower side of the fixed reduction box housing when the coal mining machine to which the fixed reduction box housing belongs works under different working surface inclination conditions are located on the same side in the left and right directions, the fixed reduction box housing is also provided with a left lower pipeline channel, a right lower pipeline channel, a left upper pipeline channel and a right upper pipeline channel extending forward and backward, and the cooling water pipe, oil pipe and cable of the coal mining machine are laid in different channels respectively. The present invention enables the hydraulic unit of the coal mining machine to work under a condition of a large working surface inclination without being affected by changes in the oil level and to always work normally.

Description

Technical Field

[0001] The invention relates to a mounting structure of a hydraulic unit used on a coal mining machine, and is particularly suitable for coal mining machines in extremely thin coal seams. Background Art

[0002] In the mining of extremely thin coal seams, in order to increase the adaptability of the coal mining machine, the fixed reduction box is usually set on the side of the conveyor and close to the coal wall, and a compact cutting transmission structure is set in the fixed reduction box. Therefore, the space that can be used as the oil tank of the hydraulic unit is relatively small. Especially when the working face has a large inclination angle, the change of the oil level in the oil tank will have a greater impact on the oil suction of the hydraulic unit, etc., and correspondingly have a greater impact on the height adjustment system on the left and right sides. Some coal mining machines have cancelled the hydraulic unit, so that the height adjustment operation cannot be performed at any time during the mining process. It can only be manually assisted when the coal mining machine has finished mining and walked to the two ends of the working face. The height adjustment operation is extremely inconvenient and time-consuming. There are also coal mining machines that simply significantly lengthen the fixed reduction box. Although it can increase the oil tank space, it will seriously affect the rapid advancement of extremely thin coal seams under conditions where the bottom plate fluctuates greatly. Summary of the invention

[0003] The purpose of the present invention is to provide a mounting structure of a hydraulic unit, so that when an ultra-thin coal seam shearer works at a relatively large working face inclination angle, the hydraulic unit thereof can always work normally without being affected by changes in the oil level.

[0004] The main technical solutions of the present invention are:

[0005] A mounting structure for a hydraulic unit comprises a fixed reduction gearbox housing and a hydraulic unit, wherein a left oil pool, a right oil pool, a left oil cylinder mounting chamber and a right oil cylinder mounting chamber are provided in the fixed reduction gearbox housing, wherein the left oil pool and the right oil pool are connected at the bottom, wherein the hydraulic unit is detachably and fixedly mounted on the fixed reduction gearbox housing and is located in one of the left and right oil cylinder mounting chambers, wherein the oil cylinder mounting chamber where the hydraulic unit is located and the oil pool on the lower side of the coal mining machine to which the fixed reduction gearbox housing belongs when working under different working surface inclination angles are located on the same side in the left-right direction.

[0006] The fixed reduction gearbox housing is also provided with a lower left pipeline channel and a lower right pipeline channel extending forward and backward, the front ends of the lower left pipeline channel and the lower right pipeline channel are closed, and the rear ends are respectively connected with the left oil pool and the right oil pool, and the front ends of the lower left pipeline channel and the lower right pipeline channel are respectively provided with an oil suction port and an oil return port, the oil suction port and the oil return port of the lower left pipeline channel are connected with the left cylinder mounting cavity, and the oil suction port and the oil return port of the lower right pipeline channel are connected with the right cylinder mounting cavity, the oil suction pipe of the hydraulic unit is connected to the oil suction port corresponding to the cylinder mounting cavity where it is located, and the oil return pipe of the cylinder control valve in the cylinder mounting cavity where the hydraulic unit is located is connected to the corresponding oil return port.

[0007] The lower left pipeline channel and the lower right pipeline channel may be cavity structures located in the solid wall of the fixed reduction box housing, or tubular steel structures laid in the fixed reduction box housing.

[0008] The oil return pipe between the hydraulic unit and the oil pool passes through one of the lower left pipeline channel and the lower right pipeline channel. The pipeline channel through which the oil return pipe passes is preferably located on the same side in the left-right direction as the cylinder installation cavity where the hydraulic unit is located.

[0009] The fixed reduction box housing may also be provided with a left upper pipeline channel and a right upper pipeline channel extending forward and backward, and the left upper pipeline channel and the right upper pipeline channel are cavity structures in the fixed reduction box housing.

[0010] One of the cooling water pipe and the cable of the coal mining machine passes through the upper left pipeline channel, and the other passes through the upper right pipeline channel. The pipeline channel through which the cooling water pipe passes is preferably located on the same side of the cylinder installation cavity where the hydraulic unit is located in the left and right directions.

[0011] The left cylinder mounting chamber and the right cylinder mounting chamber are preferably located at the frontmost side of the fixed reduction gearbox housing, the left cylinder mounting chamber and the left oil pool are the front mounting chamber of the left cutting transmission system, and the right cylinder mounting chamber and the right oil pool are the front mounting chamber of the right cutting transmission system.

[0012] The hydraulic unit preferably includes a gear pump and a first-stage planetary speed increasing mechanism and a first-stage fixed-axis gear speed increasing mechanism which are sequentially connected in transmission. The power input end and the power output end of the first-stage planetary speed increasing mechanism are respectively a planet carrier and a sun gear. The sun gear of the first-stage planetary speed increasing mechanism is coaxially spline-connected with the head end gear of the first-stage fixed-axis gear speed increasing mechanism. The terminal gear of the first-stage fixed-axis gear speed increasing mechanism is coaxially spline-connected with the transmission shaft of the gear pump. The rear end of the planet carrier of the first-stage planetary speed increasing mechanism is spline-connected with the front end of the output gear of the middle section of the cutting transmission system on the corresponding side. The cylinder mounting cavity where the hydraulic unit is located and the cutting transmission system to which the output gear connected to the planet carrier belongs are located on the same side in the left-right direction.

[0013] The front and rear ends of the output gear are respectively rotatably supported on the front and rear side walls of the fixed reduction gearbox housing. The front end of the output gear is preferably provided with two stepped grooves, the front larger and the rear smaller, and the rear groove is arranged as an internal spline. The rear end of the planetary carrier of the first-stage planetary speed increasing mechanism is arranged as an external spline, and the rear end of the planetary carrier is located in the rear groove and cooperates with the internal spline to form a spline connection.

[0014] A first end cover and a second end cover are detachably fixedly installed on the front side walls supporting the output gears on the left and right sides, wherein the front of the output gear on the same side as the hydraulic unit is the first end cover, and the front of the output gear on the other side is the second end cover, the rear part of the first end cover is inserted into the front groove of the corresponding output gear, the main body of the first-stage planetary speed increaser mechanism is installed in the inner cavity at the rear of the first end cover, the rear part of the first end cover serves as the inner gear ring of the first-stage planetary speed increaser mechanism, and the first-stage fixed-axis gear speed increaser mechanisms are all installed in the inner cavity at the front of the first end cover, the output end of the sun gear extends forward into the inner cavity at the front of the first end cover and is coaxially splined with the head gear, the gear pump is installed on the front end face of the first end cover, the transmission shaft of the gear pump extends backward into the inner cavity at the front of the first end cover and is coaxially splined with the end gear, and the second end cover closes the front side wall of the corresponding side from the front.

[0015] The beneficial effects of the present invention are:

[0016] By setting the left oil pool and the right oil pool to be interconnected, and pre-installing the hydraulic unit in the cylinder installation cavity on the lower side according to the inclination angle of the working surface, it can be ensured that the hydraulic unit is in a lower position when absorbing oil, thereby ensuring the normal operation of the hydraulic unit, and only one set of hydraulic units is needed to meet the oil supply needs of the left and right cylinders at the same time.

[0017] By using the cavity on the steel pipe or the fixed reducer housing to set up the lower left pipeline channel, the lower right pipeline channel, the upper left pipeline channel and the upper right pipeline channel, the orderly routing and mutual separation of the cooling water pipes, hydraulic unit suction return pipes and cables of the coal mining machine can be greatly facilitated, maintenance and management can be facilitated, and pipeline failures can be reduced.

[0018] Since the cylinder mounting chamber close to the hollow structure is arranged in the front mounting chamber of the cutting transmission system and in front of the oil pool, the overall center of gravity of the coal mining machine can be shifted to the mining side, which is closer to the position of the supporting legs (or shovel plates) than the center of gravity of the coal mining machine with traditional structure, thereby improving the stability of the coal mining machine in both stationary and walking states.

[0019] Since the output gear in the middle section of the cutting transmission system is used as a power output node, the power is transmitted to the gear pump through a first-stage planetary speed increasing mechanism and a first-stage fixed-axis gear speed increasing mechanism, thereby eliminating the need for the gear pump to be equipped with a separate power source such as a pump motor.

[0020] The use of the one-stage planetary speed increasing mechanism can achieve a larger speed increasing ratio with a smaller space occupation, which is not only conducive to saving installation space, but also easier to achieve matching with the cutting transmission system using a multi-pole motor.

[0021] Two stepped grooves with a larger front and a smaller rear are set at the front end of the output gear, and the rear part of the first end cover is inserted into the front groove of the output gear. At the same time, the main body of the first-stage planetary speed increasing mechanism is installed in the inner cavity at the rear part of the first end cover, which is equivalent to setting the first-stage planetary speed increasing mechanism as a whole in the front end groove of the output gear, which significantly saves axial installation space.

[0022] The first-stage fixed-axis gear speed increasing mechanism is completely arranged in the first end cover, so that the structure of the hydraulic unit is quite compact, which further saves the installation space of the hydraulic unit, especially reduces the axial space occupation, and is particularly suitable for thin or ultra-thin coal seam coal mining machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of an embodiment of the present invention;

[0024] Figure 2 A cross-sectional view of the upper and lower pipeline channels of a structure ( Figure 1 AA section of the

[0025] Figure 3 is a structural schematic diagram of an embodiment of the hydraulic unit;

[0026] Figure 4 is a schematic diagram of a partial structure of the output gear;

[0027] Figure 5 is a structural schematic diagram of an embodiment of the first end cover;

[0028] Figure 6 This is a cross-sectional view of the upper and lower pipeline channels of another structure.

[0029] Reference numerals:

[0030] 1. Hydraulic unit; 11. Gear pump; 121. Planet carrier; 122. Sun gear; 131. Head gear; 132. End gear; 133. Idle gear;

[0031] 2. Fixed reduction box housing; 21. Motor installation cavity; 22. Oil pool; 23. Tubular cavity; 24. Oil cylinder installation cavity; 25. Front installation cavity of cutting transmission system; 26. Lower pipeline channel; 27. Upper pipeline channel;

[0032] 31. Left cylinder; 32. Right cylinder;

[0033] 4. Cutting transmission system; 41. Output gear; 411. Rear groove; 412. Front groove;

[0034] 5. First end cap; 51. Rear portion of first end cap; 52. Front portion of first end cap;

[0035] 6. Second end cover;

[0036] 7. Small end cap. DETAILED DESCRIPTION

[0037] The present invention discloses a mounting structure of a hydraulic unit, such as Figure 1-6 As shown, it includes a fixed reduction box housing 2 and a hydraulic unit 1. The fixed reduction box housing is the main part of the coal mining machine body and is the main structural part for accommodating the cutting transmission system. It is provided with a plurality of different chambers. The hydraulic unit is used to provide a hydraulic oil source. The fixed reduction box housing is provided with a motor installation chamber 21, a left oil pool and a left cylinder installation chamber located on the left side of the motor installation chamber, and a right oil pool and a right cylinder installation chamber located on the right side of the motor installation chamber. The left oil pool and the right oil pool are collectively referred to as the oil pool 22, and the two are connected at the bottom through a tubular cavity 23 extending left and right in the fixed reduction box housing. The left cylinder installation chamber and the right cylinder installation chamber are collectively referred to as the cylinder installation chamber 24, and the left and right cylinders 31 and 32 are respectively installed in the left and right cylinder installation chambers. There is only one set of the hydraulic unit, and the hydraulic unit can be detachably fixedly installed on the fixed reduction box housing and is located in one of the left and right cylinder installation chambers. The oil cylinder installation cavity where the hydraulic unit is located and the oil pool on the lower side when the coal mining machine to which the fixed reduction box housing belongs works under different working surface inclination conditions are located on the same side in the left-right direction. In other words, according to the actual situation of the working surface inclination, the left and right sides of the coal mining machine to which the fixed reduction box housing belongs will most likely be one high and one low when it works in the future, and the oil will gather in the oil pool on the lower side. Therefore, pre-installing the hydraulic unit in the oil cylinder installation cavity on the lower side can ensure that the hydraulic unit is in a lower position when absorbing oil, thereby ensuring the normal operation of the hydraulic unit.

[0038] The present invention adopts a set of hydraulic units to provide hydraulic driving force for the oil cylinders on the left and right sides at the same time.

[0039] The fixed reduction box housing is also provided with a left lower pipeline channel and a right lower pipeline channel extending forward and backward, which can be collectively referred to as the lower pipeline channel 26. The front ends of the left lower pipeline channel and the right lower pipeline channel are closed, and the rear ends are respectively connected to the left oil pool and the right oil pool. The front ends of the left lower pipeline channel and the right lower pipeline channel are respectively provided with an oil suction port and an oil return port. The oil suction port and the oil return port of the left lower pipeline channel are connected to the left oil cylinder installation cavity, and the oil suction port and the oil return port of the right lower pipeline channel are connected to the right oil cylinder installation cavity. The setting of the left lower pipeline channel and the right lower pipeline channel is equivalent to setting the oil suction and return interface of the oil pool at an accessible position in the oil cylinder installation cavity, so that the pipe connection operation between the hydraulic unit and the oil cylinder control valve and the oil pool can be carried out in the oil cylinder installation cavity. When connecting, the oil suction pipe of the hydraulic unit is connected to the corresponding oil suction port of the oil cylinder installation cavity where it is located, and the oil return pipe of the oil cylinder control valve in the oil cylinder installation cavity where the hydraulic unit is located is connected to the corresponding oil return port. The oil return pipes of the left oil cylinder control valve and the right oil cylinder control valve are connected.

[0040] The left lower pipeline channel and the right lower pipeline channel may be cavity structures located in the solid wall of the fixed reduction gearbox housing (see Figure 6 ), which is machined after casting, has a simple structure, but will occupy a part of the oil pool space. The lower left pipeline channel and the lower right pipeline channel can also be a tubular steel structure laid in the fixed reduction box housing (see Figure 2 ), and less space is occupied by the oil pool. The lower left pipeline channel and the lower right pipeline channel are arranged at the lower left and lower right of the motor installation cavity respectively.

[0041] When the inclination angle of the working face of the coal mining machine is about to change in the opposite direction, the hydraulic unit should be moved to the other side of the cylinder installation cavity for installation in advance, and the suction and return oil pipes should also be moved to the other side for laying and connecting.

[0042] The fixed reduction box housing is also provided with a left upper pipeline channel and a right upper pipeline channel extending forward and backward, which can be collectively referred to as an upper pipeline channel 27. The left upper pipeline channel and the right upper pipeline channel are cavity structures on the fixed reduction box housing, opened in the thicker part of the partition wall inside the housing, and are respectively arranged at the upper left and upper right of the motor installation cavity, and close to the top of the fixed reduction box housing.

[0043] One of the cooling water pipe and the cable of the coal mining machine passes through the upper left pipeline channel, and the other passes through the upper right pipeline channel. Different pipelines are laid in different channels, which is reliable in operation and convenient for maintenance. The pipeline channel through which the cooling water pipe passes is preferably located on the same side in the left-right direction as the cylinder installation cavity where the hydraulic unit is located. The oil pipe for the hydraulic unit to supply oil to the cylinder control valve in the opposite cylinder installation cavity can also pass through the upper pipeline channel on the same side as the hydraulic unit.

[0044] The left oil cylinder installation cavity and the right oil cylinder installation cavity are preferably located at the frontmost side of the fixed reduction box housing. The left oil cylinder installation cavity and the left oil pool are the front installation cavity of the left cutting transmission system, and the right oil cylinder installation cavity and the right oil pool are the front installation cavity of the right cutting transmission system. The two can be collectively referred to as the front installation cavity of the cutting transmission system. The oil cylinder installation cavity 24 close to the cavity structure is arranged in front of the front installation cavity 25 of the cutting transmission system and the oil pool 22, so that the overall center of gravity of the coal mining machine can be shifted to the mining side, which is closer to the position of the support leg (or shovel board) than the center of gravity of the coal mining machine with a traditional structure, so that the stability of the coal mining machine in both the static state and the walking state is improved.

[0045] The hydraulic unit may include a gear pump 11 and a first-stage planetary speed increasing mechanism and a first-stage fixed-axis gear speed increasing mechanism which are sequentially connected in transmission. The power input end and the power output end of the first-stage planetary speed increasing mechanism are respectively a planet carrier 121 and a sun gear 122, the sun gear of the first-stage planetary speed increasing mechanism is coaxially splined with the head end gear 131 of the first-stage fixed-axis gear speed increasing mechanism, and the end gear 132 of the first-stage fixed-axis gear speed increasing mechanism is coaxially splined with the transmission shaft of the gear pump. The rear end of the planet carrier of the first-stage planetary speed increasing mechanism is splined with the front end of the output gear 41 of the middle section of the cutting transmission system 4 on the corresponding side in the left and right directions. The present invention uses the output gear as a node to draw out a branch of power output from the cutting transmission system, and the power is transmitted to the gear pump 11 through the first-stage planetary speed increasing mechanism and the first-stage fixed-axis gear speed increasing mechanism, so the gear pump does not need to be equipped with a pump motor separately. The oil cylinder mounting cavity where the hydraulic unit is located and the cutting transmission system to which the output gear connected to the planet carrier belongs are located on the same side in the left and right directions.

[0046] The cutting transmission system is a reduction transmission system, which uses a first-stage planetary speed-increasing mechanism and a first-stage fixed-axis gear speed-increasing mechanism to re-increase a certain node after deceleration, and finally increases the speed of the gear pump to the required speed to achieve the normal working state of the gear pump. The use of the first-stage planetary speed-increasing mechanism can achieve a larger speed-increasing ratio with a smaller space occupation, which is not only conducive to saving installation space, but also easier to achieve matching with the cutting transmission system using a multi-pole motor.

[0047] The front and rear ends of the output gear are rotatably supported on the front and rear side walls in the fixed reduction box housing. The front and rear side walls are two adjacent side walls in the fixed reduction box housing. In this embodiment, the front side wall is the partition wall between the oil cylinder mounting cavity and the front mounting cavity of the cutting transmission system on the same side, and the rear side wall is the partition wall between the front mounting cavity of the cutting transmission system and the oil pool on the same side. The front and rear ends of the output gear described in the accompanying drawings are rotatably supported on the front and rear bearing seats respectively through bearings, and the front and rear bearing seats are fixedly mounted on the front and rear side walls respectively. The front end of the output gear is preferably provided with two stepped grooves with a larger front and a smaller rear, and the groove 411 at the rear is set as an internal spline, and the rear end of the planetary carrier of the first-stage planetary speed increasing mechanism is set as an external spline, and the rear end of the planetary carrier extends backward into the groove located at the rear and cooperates with the internal spline to form a spline connection.

[0048] On the front side wall of the output gears supporting the left and right sides, a first end cover 5 is detachably fixedly installed, and the other second end cover 6 is detachably fixedly installed, wherein the front of the output gear on the same side as the hydraulic unit is the first end cover, and the front of the output gear on the other side is the second end cover. The rear part 51 of the first end cover is inserted into the front groove 412 of the corresponding output gear, and the main body of the first-stage planetary speed-increasing mechanism is installed in the inner cavity of the rear part of the first end cover, which is equivalent to the first-stage planetary speed-increasing mechanism being completely arranged in the front groove of the output gear 41, which significantly saves the axial installation space of the hydraulic unit. The rear section of the inner cavity of the rear part of the first end cover is arranged as an internal gear, that is, the rear part of the first end cover serves as the inner gear ring of the first-stage planetary speed-increasing mechanism. The first-stage fixed-axis gear speed-increasing mechanisms are all installed in the inner cavity of the front part 52 of the first end cover. The output end of the sun gear extends forward into the inner cavity of the front part of the first end cover and is coaxially splined with the head end gear. The gear pump is installed on the front end face of the first end cover, and the transmission shaft of the gear pump extends backward into the inner cavity of the front part of the first end cover and is coaxially splined with the terminal gear. Since the first-stage fixed-axis gear speed increasing mechanism is all arranged in the first end cover, the structure of the hydraulic unit is quite compact, which further saves the installation space of the hydraulic unit, especially reduces the axial space occupation, and is particularly suitable for thin or very thin coal seam mining machines. The second end cover 6 closes the front side wall of the corresponding side from the front. When the hydraulic unit needs to be replaced to the other side of the cylinder mounting cavity for installation, the original first end cover needs to be replaced with the second end cover, and the original second end cover needs to be replaced with the first end cover.

[0049] The front bearing seat may be provided with a stopper structure with an open front, which is used for positioning the first end cover and the second end cover. The matching positioning structures on the first and second end covers include an annular end surface and a cylindrical surface, and the annular end surface and the cylindrical surface are both arranged at the front of the first and second end covers. A seal is arranged between the cylindrical matching positioning surfaces between the first and second end covers and the front bearing seat.

[0050] An idler gear 133 may also be arranged between the head gear and the tail gear, and the idler gear is externally meshed with the head gear and the tail gear.

[0051] There are three inner cavities inside the first end cover. The first-stage planetary speed increasing mechanism and the first end gear are installed in the first inner cavity, the idler gear is installed in the second inner cavity, and the terminal gear and the exposed transmission shaft of the gear pump are installed in the third inner cavity. The first inner cavity is through-connected from front to back, and a small end cover 7 is also installed on the front end face of the first end cover, which is used to close the first inner cavity from the front, that is, to close the first end cover inner cavity where the first end gear is located. The gear pump closes the second and third inner cavities from the front. The front end of the first end gear is rotatably supported on the small end cover through a bearing, and the rear end is rotatably supported on the first end cover through a bearing.

[0052] The front and rear directions referred to in this article correspond to Figure 1 Up and down direction.

Claims

1. A mounting structure of a hydraulic unit, characterized in that: The hydraulic unit comprises a fixed reduction gearbox housing and a hydraulic unit, wherein a left oil pool, a right oil pool, a left oil cylinder mounting chamber and a right oil cylinder mounting chamber are arranged in the fixed reduction gearbox housing, wherein the left oil pool and the right oil pool are connected at the bottom, wherein the hydraulic unit is detachably fixedly mounted on the fixed reduction gearbox housing and is located in one of the left and right oil cylinder mounting chambers, wherein the oil cylinder mounting chamber where the hydraulic unit is located and the oil pool on the lower side when the coal mining machine to which the fixed reduction gearbox housing belongs works under different working surface inclination conditions are located on the same side in the left and right directions; a left lower pipeline channel and a right lower pipeline channel extending forward and backward are also arranged in the fixed reduction gearbox housing, wherein the front end seals of the left lower pipeline channel and the right lower pipeline channel are The lower left pipeline channel and the lower right pipeline channel are respectively closed, and the rear ends are connected with the left oil pool and the right oil pool, and the front ends of the lower left pipeline channel and the lower right pipeline channel are respectively provided with an oil suction port and an oil return port, the oil suction port and the oil return port of the lower left pipeline channel are connected with the left cylinder mounting cavity, and the oil suction port and the oil return port of the lower right pipeline channel are connected with the right cylinder mounting cavity, the oil suction pipe of the hydraulic unit is connected to the oil suction port corresponding to the cylinder mounting cavity where it is located, and the oil return pipe of the cylinder control valve in the cylinder mounting cavity where the hydraulic unit is located is connected to the corresponding oil return port; the lower left pipeline channel and the lower right pipeline channel are cavity structures located in the solid wall of the fixed reduction gearbox housing, or are tubular steel structures laid in the fixed reduction gearbox housing.

2. The installation structure of the hydraulic unit according to claim 1, characterized in that: The fixed reduction box housing is also provided with a left upper pipeline channel and a right upper pipeline channel extending forward and backward. The left upper pipeline channel and the right upper pipeline channel are cavity structures in the fixed reduction box housing.

3. The installation structure of the hydraulic unit according to claim 2, characterized in that: One of the cooling water pipe and the cable of the coal mining machine passes through the upper left pipeline channel, and the other passes through the upper right pipeline channel. The pipeline channel through which the cooling water pipe passes is located on the same side of the cylinder installation cavity where the hydraulic unit is located in the left and right directions.

4. The installation structure of the hydraulic unit according to claim 1, 2 or 3, characterized in that: The left cylinder mounting chamber and the right cylinder mounting chamber are located at the frontmost side of the fixed reduction gearbox housing. The left cylinder mounting chamber and the left oil pool are the front mounting chambers of the left cutting transmission system, and the right cylinder mounting chamber and the right oil pool are the front mounting chambers of the right cutting transmission system.

5. The installation structure of the hydraulic unit according to claim 4, characterized in that: The hydraulic unit includes a gear pump and a first-stage planetary speed increasing mechanism and a first-stage fixed-axis gear speed increasing mechanism which are sequentially connected in transmission. The power input end and the power output end of the first-stage planetary speed increasing mechanism are respectively a planet carrier and a sun gear. The sun gear of the first-stage planetary speed increasing mechanism is coaxially spline-connected with the head end gear of the first-stage fixed-axis gear speed increasing mechanism. The end gear of the first-stage fixed-axis gear speed increasing mechanism is coaxially spline-connected with the transmission shaft of the gear pump. The rear end of the planet carrier of the first-stage planetary speed increasing mechanism is spline-connected with the front end of the output gear of the middle section of the cutting transmission system on the corresponding side. The cylinder mounting cavity where the hydraulic unit is located and the cutting transmission system to which the output gear connected to the planet carrier belongs are located on the same side in the left-right direction.

6. The installation structure of the hydraulic unit according to claim 5, characterized in that: The front and rear ends of the output gear are respectively rotatably supported on the front and rear side walls of the fixed reduction box housing, the front end of the output gear is provided with two stepped grooves, the front larger and the rear smaller, the rear groove is arranged as an internal spline, the rear end of the planetary carrier of the first-stage planetary speed increasing mechanism is arranged as an external spline, the rear end of the planetary carrier is located in the rear groove and cooperates with the internal spline to form a spline connection.

7. The installation structure of the hydraulic unit according to claim 6, characterized in that: A first end cover and a second end cover are detachably fixedly installed on the front side walls supporting the output gears on the left and right sides, wherein the front of the output gear on the same side as the hydraulic unit is the first end cover, and the front of the output gear on the other side is the second end cover, the rear part of the first end cover is inserted into the front groove of the corresponding output gear, the main body of the first-stage planetary speed increaser mechanism is installed in the inner cavity at the rear of the first end cover, the rear part of the first end cover serves as the inner gear ring of the first-stage planetary speed increaser mechanism, and the first-stage fixed-axis gear speed increaser mechanisms are all installed in the inner cavity at the front of the first end cover, the output end of the sun gear extends forward into the inner cavity at the front of the first end cover and is coaxially splined with the head gear, the gear pump is installed on the front end face of the first end cover, the transmission shaft of the gear pump extends backward into the inner cavity at the front of the first end cover and is coaxially splined with the end gear, and the second end cover closes the front side wall of the corresponding side from the front.

8. The installation structure of the hydraulic unit according to claim 7, characterized in that: An idler wheel is also arranged between the first end gear and the last end gear, and the idler wheel is externally meshed with the first end gear and the last end gear.

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