Large-torque hydraulic brake for coal mining machine

Abstract

The large-torque hydraulic brake for the coal mining machine comprises a shell, a rear cover, a spline housing, a single-rod piston cylinder and a brake assembly, a front cavity and a rear cavity of the single-rod piston cylinder are a rodless cavity and a rod cavity respectively, a spring is arranged in the rodless cavity, and the rod cavity is communicated with a control loop. A cylinder barrel of the piston cylinder, a shell and a rear cover are sequentially arranged from front to back and are coaxially and fixedly connected, a circular groove is formed in the extending end of the piston rod, and the front portion and the rear portion of the spline sleeve are arranged in the circular groove and a central through hole of the rear cover respectively. The brake assembly comprises a plurality of inner friction plates and outer friction plates which are alternately overlapped in the axial direction and partially or completely overlapped in the radial direction, the inner friction plates and the outer friction plates are circumferentially fixed to the outer side of the spline housing and the inner side of the shell correspondingly, and the piston rod and the rear cover axially limit the brake assembly from front to back correspondingly. Fins extending outwards are arranged in the middles of the outer cylindrical surfaces of the inner friction plates in the thickness direction, and wave-shaped spring pieces are arranged between the fins and the adjacent outer friction plates. The utility model has the advantages of compact structure, less heat and long service life.

Description

Technical Field

[0001] The utility model relates to a hydraulic brake for a coal mining machine, in particular to a hydraulic brake which does not generate abnormal heat during brake release operation. Background Art

[0002] As a shearer's anti-skid device, the brake directly impacts coal mine safety. When the shearer is stopped, the brake is engaged, preventing it from sliding down at a certain angle. When the unit's start command is issued, the brake quickly releases, allowing the shearer to begin moving.

[0003] There are various types of brakes on the market, but they are large in size and cannot adapt to the narrow space of coal mining machines. They are also expensive to produce and have poor versatility on coal mining machines. Therefore, they basically cannot be directly applied to coal mining machines.

[0004] Existing brakes for coal mining machines usually use disc friction plates. When the brake is released, the internal friction plates rotate and shear the oil film, which can easily cause heat. Moreover, the larger the torque of the brake, the more pairs of friction plates there are, and the more abnormal heating occurs, which often leads to failure and damage of the brake oil chamber seal. Utility Model Content

[0005] The utility model provides a large-torque hydraulic brake for a coal mining machine, which has a compact and simple structure, a small volume, low heat generation, good safety performance and a long service life.

[0006] The main technical solutions of this utility model are:

[0007] A high-torque hydraulic brake for a coal mining machine comprises a housing, a rear cover, a spline sleeve, a single-rod piston cylinder and a brake assembly. The front and rear chambers of the single-rod piston cylinder are respectively a rodless chamber and a rod chamber. A spring is provided in the rodless chamber, which is kept in a compressed state. The rod chamber is connected to the hydraulic control circuit. The housing and the rear cover are both annular disc parts. The cylinder barrel, housing and rear cover of the single-rod piston cylinder are arranged in sequence from front to back and the three are coaxially fixedly connected by passing long bolts. A circular groove is provided on the end face of the extended end of the piston rod of the single-rod piston cylinder. The front and rear of the spline sleeve are respectively arranged on the circular groove and the In the central through hole of the rear cover, the spline sleeve and the rear cover are positioned axially and radially by means of a stopper, and the spline sleeve is restricted from moving backward by a retaining ring installed on the rear cover. The brake assembly includes multiple inner friction plates and multiple outer friction plates, the main bodies of the inner friction plates and the outer friction plates are both annular, the inner and outer friction plates are alternately stacked in the axial direction, and the inner and outer friction plates are coaxial in the radial direction, and their respective main bodies remain partially or completely overlapped, the inner edge of the main body of the inner friction plate is provided with multiple inner claws extending radially inward, and the outer cylindrical surface of the main body of the inner friction plate is provided with multiple fins extending radially outward. The thickness of the fin is smaller than the thickness of the main body of the inner friction plate, and the fin is centered relative to the main body of the inner friction plate in the thickness direction. The distance between the single-side end face of the fin and the corresponding side end face of the main body of the inner friction plate is called the shoulder width. The outer edge of the main body of the outer friction plate is provided with a plurality of radially outwardly extending outer claws. The inner hole of the spline sleeve is a spline hole. The outer cylindrical surface of the spline sleeve is provided with a plurality of axially penetrating external grooves. The inner friction plate is sleeved on the spline sleeve and the inner claws are embedded in the outer grooves one by one and are connected to the corresponding outer grooves for sliding back and forth. The inner cylindrical surface of the outer shell is provided with a plurality of axially penetrating internal grooves. The outer friction plate is installed in the inner hole of the outer shell and the outer claws are embedded in the inner groove one by one and are connected to the corresponding inner groove for front and rear sliding. The piston rod and the rear cover respectively limit the brake assembly axially from the front and rear directions. A wave spring sheet is arranged between the fin of each inner friction plate and the adjacent outer friction plate. The thickness of the wave spring sheet is not greater than the shoulder width, and the free height of the wave spring sheet is greater than the shoulder width. When oil enters the rod cavity, the brake is released, and the adjacent inner and outer friction plates are separated from each other. When oil returns to the rod cavity, the brake is engaged, and the main bodies of the adjacent inner and outer friction plates are in close contact and there is no relative rotation.

[0008] The spring is preferably a disc spring.

[0009] An annular sealing groove is respectively provided on the outer cylindrical surface of the piston of the piston cylinder and the inner cylindrical surface of the cylinder barrel of the piston cylinder and the piston rod slidingly matched. A retaining ring and an O-ring are provided in the sealing groove. The retaining ring on the piston and the retaining ring on the cylinder barrel are respectively in front of and behind the corresponding O-ring.

[0010] The cylinder barrel of the piston cylinder and the outer shell are positioned axially and radially by a circular stop, and the outer shell and the rear cover are positioned axially and radially by a circular stop.

[0011] An annular groove is provided on the front end surface of the piston of the piston cylinder, and the rear portion of the spring is installed in the annular groove.

[0012] The high-torque hydraulic brake for the coal mining machine adopts a wet working mode. The space surrounded by the piston cylinder, the outer shell, the rear cover and the spline sleeve is a friction chamber. The gap between the inner and outer friction plates and the radial gap between the spline sleeve and the circular groove become a channel connecting the friction chamber and the inner hole of the spline sleeve.

[0013] When the brake is released, the main body distance between adjacent inner and outer friction plates is preferably maintained at 0.3 to 0.5 mm.

[0014] The high-torque hydraulic brake for the coal mining machine also includes a warning screw and a plug. The rear end of the warning screw is a threaded portion, and the front part is a smooth rod portion. There is a radially outward-protruding flange between the threaded portion and the smooth rod portion. The middle part of the piston of the piston cylinder is also provided with a central threaded hole that passes through the front and back. The threaded portion of the warning screw is threadedly connected in the central threaded hole. A plug mounting through hole is provided on the front wall of the cylinder barrel. The plug is installed in the plug mounting through hole. The flange is used for axial positioning of the warning screw relative to the piston; a plug mounting through hole is provided on the front wall of the cylinder barrel. The plug is installed in the plug mounting through hole. The smooth rod portion of the warning screw passes through the plug and is connected to the plug in a front-back sliding manner. A seal is provided between the smooth rod portion and the sliding contact surface of the plug.

[0015] A warning mark may be provided on the cylindrical surface of the polished rod portion, and the warning mark is located in front of the front end surface of the cylinder barrel during initial installation and in the brake state.

[0016] During initial installation and in the brake state, the warning mark is 3-5 mm away from the front end surface of the cylinder.

[0017] The beneficial effects of the utility model are:

[0018] By arranging a wave spring sheet between the fin of each inner friction plate and the adjacent outer friction plate, when the brake is released, the wave spring sheet stretches axially to restore the free height, forcing the adjacent inner and outer friction plates to separate evenly, ensuring the gap between each pair of inner and outer friction plates, preventing the gap between the inner and outer friction plates from being too small, resulting in the oil film thickness between the inner and outer friction plates being too thin, and further preventing the excessive heat caused by the continuous shearing of the thin oil film during the rotation of the inner friction plate, thereby solving the problem of abnormal brake heating caused by shearing the oil film.

[0019] The material of the wave spring sheet is usually 65Mn. Compared with rubber material, it can withstand the high temperature during the operation of the coal mining machine brake, especially the local high temperature of more than 100 degrees between the friction plates. It is not easy to age, deform or even burn out, and it works more reliably and has a longer service life.

[0020] The wave spring sheet has a simple structure and is very easy to install. The force of the wave spring to open the outer friction sheet acts on the outer friction sheet in multiple areas evenly distributed on the entire annular plane, so that the axial force on the outer friction sheet is more uniform and there will be no tilting or jamming.

[0021] The provision of the warning screw solves the problem that conventional brakes lack a means for detecting friction plate wear, thereby greatly facilitating underground maintenance and use.

[0022] The central threaded hole can be used to release the brake mechanically to ensure that the brake can be released reliably when the hydraulic brake system or the brake fails and needs maintenance, and can also be used for oiling during normal use, thus killing two birds with one stone. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 An end view of an embodiment of the high-torque hydraulic brake for a coal mining machine;

[0024] Figure 2 for Figure 1 AA rotation section view (brake state);

[0025] Figure 3 for Figure 2 K magnified image;

[0026] Figure 4 for Figure 2 Schematic diagram of the axial structure of the spline sleeve;

[0027] Figure 5 for Figure 2 Schematic diagram of the axial structure of the inner friction plate;

[0028] Figure 6 for Figure 5 BB cross-sectional view;

[0029] Figure 7 for Figure 2 Schematic diagram of the structure of the wave spring sheet;

[0030] Figure 8 for Figure 7 Side view of

[0031] Figure 9 for Figure 2 The figure shows the assembly diagram of the high-torque hydraulic brake for the coal mining machine and the high-speed shaft of the traction transmission system.

[0032] Reference numerals:

[0033] 1. piston; 2. cylinder; 3. spring; 4. spline sleeve; 5. housing; 6. inner friction plate; 61. main body of inner friction plate; 62. inner side claw; 63. fin; 7. outer friction plate; 8. rear cover; 9. wave spring plate; 10. screw plug; 11. end cover; 12. warning screw; 13. high-speed shaft; 14. first long bolt; 15. second long bolt. DETAILED DESCRIPTION

[0034] As Figure 1-9 shown, the utility model discloses a kind of big torque hydraulic brakes for coal mining machine (can be simply called brake), belong to disc brake, including shell 5, rear cover 8, spline sleeve 4, single-rod piston cylinder and brake assembly.The front and rear cavities of single-rod piston cylinder are rodless chamber and rod chamber respectively, spring 3 is equipped in rodless chamber, spring keeps compressed state, rod chamber is communicated low-pressure hydraulic control circuit.Housing and rear cover are circular ring disc type parts.Single-rod piston cylinder's cylinder barrel, housing and rear cover are sequentially arranged from front to back and three are coaxially fixed connection by the mode of first long bolt 14 being threaded.Set with circular recess in the outer end face of piston rod of single-rod piston cylinder, the front and rear of spline sleeve are set in the circular recess and the central through-hole of rear cover respectively.Spline sleeve and rear cover are positioned axially and radially by stop, and spline sleeve is limited to move backward by the check ring installed on rear cover.

[0035] The brake assembly comprises a plurality of inner friction plates 6 and a plurality of outer friction plates 7, the main bodies of the inner friction plates and the outer friction plates are circular annular, the inner friction plates and the outer friction plates are alternately stacked in the axial direction, and the main bodies of the inner friction plates and the outer friction plates are coaxial and partially or wholly overlapped in the radial direction. The circular annular disc surfaces of the main bodies of the adjacent inner friction plates and the outer friction plates form a friction pair, and the brake has a plurality of friction pairs. The inner edge of the main body 61 of the inner friction plate is provided with a plurality of (for example, 3) radially inward extending inner side claws 62, and the outer cylindrical surface of the main body of the inner friction plate is provided with a plurality of (4 in the embodiment shown in the figure) radially outward extending fins 63, the thickness of the fins is less than the thickness of the main body of the inner friction plate, and the fins are centrally arranged in the thickness direction relative to the main body of the inner friction plate. That is, there is a distance between the one-sided end surface of the fin and the corresponding side end surface of the main body of the inner friction plate, which can be referred to as the shoulder width w for the sake of simplicity. The outer edge of the main body of the outer friction plate is provided with a plurality of (for example, 6) radially outward extending outer side claws. The inner hole of the spline sleeve is a spline hole, and the outer cylindrical surface of the spline sleeve is provided with a plurality of axially extending outer clamping grooves, the inner friction plate is sleeved on the spline sleeve, and the inner side claws are embedded in the outer clamping grooves one by one and are connected with the corresponding outer clamping grooves in front and back sliding connection. The inner cylindrical surface of the outer shell is provided with a plurality of axially extending inner clamping grooves, the outer friction plate is fitted into the inner hole of the outer shell, and the outer side claws are embedded in the inner clamping grooves one by one and are connected with the corresponding inner clamping grooves in front and back sliding connection. The outer clamping grooves are used to limit the rotation of the outer friction plate, and the inner clamping grooves are used to synchronize the rotation or stop of the spline sleeve and the inner friction plate. The outer clamping grooves and the inner clamping grooves are preferably circumferentially distributed according to their respective axes. The piston rod of the single-rod piston cylinder and the rear cover 8 are respectively axially limited from the front and rear directions to the brake assembly.

[0036] The front and rear ends of the brake assembly are preferably outer friction plates.

[0037] A wave spring sheet 9 is arranged between the fins of each inner friction plate and the adjacent outer friction plate. The thickness of the wave spring sheet is not greater than the shoulder width w, and the free height of the wave spring sheet is greater than the shoulder width w. In the embodiment shown in the figure, the thickness of the wave spring sheet is 0.4 mm, and the free height is 1.0 mm.

[0038] A coal mining machine is provided with two brake assemblies, which are respectively installed at the left and right traction shafts (i.e. the high-speed shaft 13 of the traction transmission system) of the coal mining machine (see Figure 9), specifically the outer spline of the high-speed shaft end and the inner spline of the spline sleeve are spline connected. When installed, the entire brake is first sleeved on the spline of the high-speed shaft gear, and then fixed on the traction part shell by 12 second long bolts 15. In order to avoid mistakenly removing the first long bolt when the brake is removed as a whole, a mark is made on the head of the first long bolt. In the parking state, the rod cavity returns oil, the piston 1 of the piston cylinder moves backward under the thrust of the spring 3, the axial pressure of the spring 3 makes the inner and outer friction plates press tightly against each other, and the brake is engaged. In the engaged state, the adjacent inner and outer friction plates are in close contact and do not rotate relative to each other, the spline sleeve is also stationary relative to the outer shell with the inner friction plate, and a braking torque is applied to the high-speed shaft. The wave spring plate is axially compressed between the fins of the outer friction plate and the adjacent inner friction plate. Since the spring force of the wave spring plate is very small, it does not affect the braking torque. When the coal mining machine is ready to start running, the rod cavity is filled with oil, the piston 1 moves forward under the hydraulic pressure, overcoming the spring force of the spring 3, and the axial pressure between the adjacent inner and outer friction plates is removed, the brake is released, and the spline sleeve drives the inner friction plate to rotate relative to the outer shell, so it does not affect the rotation of the high-speed shaft.

[0039] Because the free height of the wave spring plate is greater than the shoulder width w, once the axial pressure is removed, the wave spring plate axially expands to restore the free height, which uniformly pushes the adjacent inner and outer friction plates apart, preventing the gap between the inner and outer friction plates from being too small, which would cause the oil film thickness between the inner and outer friction plates to be too thin, and further prevent a large amount of heat from being generated due to the continuous shearing of the thin oil film when the inner friction plate rotates, thereby solving the problem of abnormal heating of the brake caused by shearing the oil film.

[0040] The temperature of the coal mining machine brake is relatively high during operation, especially the local temperature between the friction plates, which can reach more than 100 degrees. The material of the wave spring plate is usually 65Mn, which is not prone to aging and deformation or even burning out compared to rubber materials, and is more reliable and has a longer service life.

[0041] The wave spring plate is naturally positioned in the annular space formed by the outer cylindrical surface of the inner friction plate, the fins of the inner friction plate, and the adjacent outer friction plate, and the structure is very simple and easy to assemble. The force of the wave spring plate to expand the outer friction plate is evenly distributed in multiple areas on the entire annular plane, which makes the axial force on the outer friction plate more uniform and prevents tilting and jamming,

[0042] The thickness of the wave spring plate in the figure is 0.4mm, the disc surface is wavy, and the free height is 1.0mm.

[0043] The spring is preferably a disc spring, which has large stiffness, strong shock absorption and vibration absorption capacity, can withstand large loads with small deformation, and occupies small axial space, so the brake can be more compact in the axial direction.

[0044] The outer cylinder surface of the piston of the piston cylinder and the inner cylinder surface of the cylinder barrel and the piston rod sliding fit are respectively provided with annular sealing grooves, and the sealing grooves are provided with check rings and O-rings, the check ring on the piston is in front of and behind the corresponding O-ring, i.e. on the low pressure side of the corresponding O-ring, compared with the sealing structure provided with only O-rings, the check ring can prevent the pressure oil from extruding the O-ring into the gap between the piston and the cylinder barrel and the piston rod and the cylinder barrel, thereby prolonging the service life of the O-ring. The O-ring is preferably made of fluororubber sealing material, which has better heat resistance and can adapt to high temperature working environment and is not easy to age and deform.

[0045] The cylinder barrel 2 and the shell 5 can be axially and radially positioned by a circular stop. The shell 5 and the rear cover 8 can also be axially and radially positioned by a circular stop. In the drawings, the shell is a circular ring without a stop, and the rear end surface of the cylinder barrel and the front end surface of the rear cover are each provided with a circular outer stop. The rear end surface of the cylinder barrel and the front end surface of the rear cover are each provided with a sealing gasket at the interface with the shell.

[0046] The front end surface of the piston is provided with an annular groove, and the rear part of the spring is mounted in the annular groove. Since the spring is partially embedded in the piston, the axial size of the brake can be further reduced.

[0047] The brake preferably adopts a wet working mode to reduce the wear rate of the friction plate and not produce sparks. Specifically, the space surrounded by the piston cylinder, the shell, the rear cover and the spline sleeve is a friction chamber, the gap between the inner and outer friction plates and the radial gap between the spline sleeve and the circular groove become channels connecting the friction chamber and the inner hole of the spline sleeve, and the gear oil in the traction shell flows through the gap between the spline sleeve and the high-speed shaft and enters the friction chamber through the above-mentioned channels, and the gear oil serves as the working oil of the friction plate.

[0048] The main body distance between the adjacent inner and outer friction plates is preferably kept at 0.3-0.5mm when the brake is released, which not only avoids abnormal heating caused by too thin oil film when the inner friction plate rotates, but also avoids the brake being not sensitive caused by too thick oil film between the inner and outer friction plates.

[0049] The brake further preferably comprises a warning screw 12 and a screw plug 10. The rear end of the warning screw is a threaded portion, the front end is a light rod portion, and a radially outwardly convex flange is arranged between the threaded portion and the light rod portion. In the embodiment shown in the drawings, the threaded portion adopts M16 threads. The middle portion of the piston is provided with a central threaded hole that extends through the front and rear of the piston, i.e., the central threaded hole is in communication with the circular groove. The threaded portion of the warning screw is threadedly connected in the central threaded hole, and the flange is used for axial positioning of the warning screw relative to the piston. The maximum screwing depth of the threaded portion is determined by the flange, and the warning screw will move back and forth with the piston. The front side wall of the cylinder barrel is provided with a screw plug mounting through hole, and the screw plug is mounted in the screw plug mounting through hole. The light rod portion of the warning screw passes through the screw plug and is in sliding connection with the screw plug, and a seal is arranged between the sliding contact surface of the light rod portion and the screw plug to prevent coal cinder and water from entering the brake and to avoid leakage of oil in the brake. In the drawings, the seal is an O-shaped sealing ring arranged in an annular sealing groove formed in the cylindrical surface of the light rod portion in the circumferential direction.

[0050] A warning mark is preferably arranged on the cylindrical surface of the light rod portion, such as a dot, a line, or a whole-circle mark arranged on the cylindrical surface of the light rod portion. In the initial installation and brake holding state, the warning mark is located in front of the front end face of the cylinder barrel. With the wear of the inner and outer friction plates, the piston will move more and more towards the rear in the brake holding state, and the position of the warning mark will also move more and more close to the cylinder barrel. When the position of the warning mark is close to a certain extent, the inner and outer friction plates have reached the maximum allowable wear, and at this time, the inner and outer friction plates must be replaced in groups, and usually the brake assembly is replaced as a whole. The extent to which the inner and outer friction plates need to be replaced can be determined according to the actual specific circumstances. In the embodiment, it is considered that the inner and outer friction plates need to be replaced when the position of the warning mark is found to sink into the front end face of the cylinder barrel.

[0051] In the initial installation and brake holding state, the warning mark is preferably 3-5 mm away from the front end face of the cylinder barrel, and in the embodiment shown in the drawings, the distance is 3 mm, i.e., the total wear of the inner and outer friction plates reaches 3 mm, and the inner and outer friction plates need to be replaced.

[0052] The arrangement of the warning screw can truly reflect the wear of the friction plates, and it is convenient to master the change of the wear of the friction plates at any time underground, and the problem that manual detection is difficult or has large detection error due to the poor working environment and the installation position, and the inner and outer friction plates are excessively worn without being found and corrected in time, resulting in insufficient braking torque and even causing safety accidents such as vehicle slipping.

[0053] The cylinder barrel can comprise a cylinder body 2 and an end cover 11 fixed at the front end opening of the cylinder body, and the end cover serves as the front side wall of the cylinder barrel. The screw plug mounting through hole is arranged on the end cover.

[0054] The central threaded hole can be used to inject oil into the friction chamber. The oil injection into the friction chamber is mainly applied to two occasions, one is before installation, when the brake is tested, oil needs to be injected into the friction chamber, and the other is when the working face has a large inclination angle or a certain strike angle, the coal mining machine needs to check whether the gear oil flows into the friction chamber of the brake on the higher end of the traction part before starting, and if there is no oil, oil needs to be injected.

[0055] A plurality of through holes extending forward and backward around the central threaded hole of the piston can also be provided, and the plurality of through holes are distributed in a circle in the figure. On the one hand, the through hole can also be used for oil injection, so as to accelerate the oil injection speed, and on the other hand, when the brake is sleeved on the gear spline, the friction chamber is a closed chamber, and the through hole can be used for exhaust.

[0056] The central threaded hole can also be used for mechanical brake release. The specific operation is as follows: first, the plug 10 is removed, a flat pad is placed on the front end face of the cylinder or the end cover, a bolt (M16) is inserted into the central threaded hole of the piston through the flat pad, and the bolt head is abutted on the flat pad. Continue to tighten the bolt, the piston is lifted, and the brake is immediately released. The operation is convenient and reliable, and when the hydraulic brake system or the brake needs to be repaired due to failure, the brake can be released in this way.

[0057] The large-torque hydraulic brake for the coal mining machine has a compact structure, the static braking torque can reach 1600 N·m, the dynamic braking torque can reach 800 N·m, and the braking needs of the coal mining machine with a weight of 230 tons can be met.

[0058] The front and the back referred to in the present text correspond to Figure 2 The left and the right under the perspective are for convenient expression, and are not limited to absolute positions.

Claims

1. A high-torque hydraulic brake for a coal mining machine, characterized by: It includes a shell, a rear cover, a spline sleeve, a single-rod piston cylinder and a brake assembly. The front and rear chambers of the single-rod piston cylinder are respectively a rodless chamber and a rod chamber. A spring is provided in the rodless chamber, which is kept in a compressed state. The rod chamber is connected to the hydraulic control circuit. The shell and the rear cover are both annular disc parts. The cylinder barrel, shell and rear cover of the single-rod piston cylinder are arranged in sequence from front to back and the three are coaxially fixedly connected by passing long bolts. A circular groove is provided on the end face of the extended end of the piston rod of the single-rod piston cylinder. The front and rear parts of the spline sleeve are respectively arranged in the circular groove and the central through hole of the rear cover. The spline sleeve is provided in the central through hole of the circular groove and the rear cover. The sleeve and the rear cover are positioned axially and radially by means of a stopper, and the rear cover is restricted from moving backward by a retaining ring installed on the rear cover. The brake assembly includes multiple inner friction plates and multiple outer friction plates, and the main bodies of the inner friction plates and the outer friction plates are both annular. The inner and outer friction plates are alternately stacked in the axial direction, and the inner and outer friction plates are coaxial in the radial direction, and their main bodies remain partially or completely overlapped. The inner edge of the main body of the inner friction plate is provided with multiple inner claws extending radially inward, and the outer cylindrical surface of the main body of the inner friction plate is provided with multiple fins extending radially outward, and the thickness of the fins is less than that of the inner The thickness of the friction plate body, and the fin is centered relative to the main body of the inner friction plate in the thickness direction. The distance between the single-side end face of the fin and the corresponding side end face of the inner friction plate body is called the shoulder width. The outer edge of the main body of the outer friction plate is provided with a plurality of radially outwardly extending outer claws. The inner hole of the spline sleeve is a spline hole. The outer cylindrical surface of the spline sleeve is provided with a plurality of axially penetrating outer card grooves. The inner friction plate is sleeved on the spline sleeve and the inner claws are embedded in the outer card grooves one by one and are connected to the corresponding outer card grooves for sliding back and forth. The inner cylindrical surface of the outer shell is provided with a plurality of axially penetrating inner card grooves. The plate is installed in the inner hole of the outer shell and the outer claws are embedded in the inner groove one by one and are connected to the corresponding inner groove for front and rear sliding. The piston rod and the rear cover respectively limit the brake assembly axially from the front and rear directions. A wave spring plate is arranged between the fin of each inner friction plate and the adjacent outer friction plate. The thickness of the wave spring plate is not greater than the shoulder width, and the free height of the wave spring plate is greater than the shoulder width. When oil enters the rod cavity, the brake is released, and the adjacent inner and outer friction plates are separated from each other. When oil returns to the rod cavity, the brake is engaged, and the main bodies of the adjacent inner and outer friction plates are in close contact and there is no relative rotation.

2. The high-torque hydraulic brake for a coal mining machine according to claim 1, characterized in that: The spring is a disc spring.

3. The high-torque hydraulic brake for a coal mining machine according to claim 1, characterized in that: An annular sealing groove is respectively provided on the outer cylindrical surface of the piston of the piston cylinder and the inner cylindrical surface of the cylinder barrel of the piston cylinder and the piston rod slidingly matched. A retaining ring and an O-ring are provided in the sealing groove. The retaining ring on the piston and the retaining ring on the cylinder barrel are respectively in front of and behind the corresponding O-ring.

4. The high-torque hydraulic brake for a coal mining machine according to claim 1, characterized in that: The cylinder barrel of the piston cylinder and the outer shell are positioned axially and radially by a circular stop, and the outer shell and the rear cover are positioned axially and radially by a circular stop.

5. The high-torque hydraulic brake for a coal mining machine according to claim 1, characterized in that: An annular groove is provided on the front end surface of the piston of the piston cylinder, and the rear portion of the spring is installed in the annular groove.

6. The high-torque hydraulic brake for a coal mining machine according to claim 1, characterized in that: It adopts a wet working mode. The space enclosed by the piston cylinder, outer shell, rear cover and spline sleeve is the friction chamber. The gap between the inner and outer friction plates and the radial gap between the spline sleeve and the circular groove become the channel connecting the friction chamber and the inner hole of the spline sleeve.

7. The high-torque hydraulic brake for a coal mining machine according to claim 1, 2, 3, 4, 5 or 6, characterized in that: When the brake is released, the main body distance between adjacent inner and outer friction plates is maintained at 0.3 to 0.5 mm.

8. The high-torque hydraulic brake for a coal mining machine according to claim 1, 2, 3, 4, 5 or 6, characterized in that: It also includes a warning screw and a plug, the rear end of the warning screw is a threaded portion, the front part is a smooth rod portion, and a radially outward-protruding flange is provided between the threaded portion and the smooth rod portion. The middle part of the piston of the piston cylinder is also provided with a central threaded hole that passes through the front and back. The threaded portion of the warning screw is threadedly connected in the central threaded hole, and a plug mounting through hole is provided on the front side wall of the cylinder barrel. The plug is installed in the plug mounting through hole, and the flange is used for axial positioning of the warning screw relative to the piston; a plug mounting through hole is provided on the front side wall of the cylinder barrel, and the plug is installed in the plug mounting through hole. The smooth rod portion of the warning screw passes through the plug and is connected to the plug in a front-back sliding manner, and a seal is provided between the smooth rod portion and the sliding contact surface of the plug.

9. The high-torque hydraulic brake for a coal mining machine according to claim 8, characterized in that: A warning mark is provided on the cylindrical surface of the polished rod portion. In the initial installation and brake state, the warning mark is located in front of the front end surface of the cylinder.

10. The high-torque hydraulic brake for a coal mining machine according to claim 9, characterized in that: During initial installation and in the brake-engaging state, the warning mark is 3-5 mm away from the front end surface of the cylinder.

11. The high-torque hydraulic brake for a coal mining machine according to claim 7, characterized in that: It also includes a warning screw and a plug, the rear end of the warning screw is a threaded portion, the front part is a smooth rod portion, and a radially outward-protruding flange is provided between the threaded portion and the smooth rod portion. The middle part of the piston of the piston cylinder is also provided with a central threaded hole that passes through the front and back. The threaded portion of the warning screw is threadedly connected in the central threaded hole, and a plug mounting through hole is provided on the front side wall of the cylinder barrel. The plug is installed in the plug mounting through hole, and the flange is used for axial positioning of the warning screw relative to the piston; a plug mounting through hole is provided on the front side wall of the cylinder barrel, and the plug is installed in the plug mounting through hole. The smooth rod portion of the warning screw passes through the plug and is connected to the plug in a front-back sliding manner, and a seal is provided between the smooth rod portion and the sliding contact surface of the plug.

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