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 a piston rod of the piston cylinder, 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 invention has the advantages of compact structure, less heat and long service life.

Description

Technical Field

[0001] The invention 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 an anti-skid device for coal mining machines, the brake directly affects the safe production of coal mines. When the machine is stopped, the brake is in a holding state to ensure that the coal mining machine does not slide down on a certain inclination working surface. When the unit is pulled to start the command, the brake is quickly released and the coal mining machine starts to move.

[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 manufacture 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 inner friction plate rotates and shears the oil film, which easily causes heat. Moreover, the larger the torque of the brake, the more abnormal heating occurs due to the greater number of friction plates, which often leads to failure and damage of the brake oil chamber seal. Summary of the invention

[0005] The invention 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 the present invention 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 arranged in the rodless chamber, and the spring is kept in a compressed state. The rod chamber is connected to a hydraulic control circuit. The housing and the rear cover are both annular disk-like 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. 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 and the rear cover are positioned axially and radially by a stopper, and the spline sleeve is limited to move 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 main bodies are partially or completely overlapped. The inner edge of the main body of the inner friction plate is provided with a plurality of inner claws extending radially inward, and the outer cylindrical surface of the main body of the inner friction plate is provided with a plurality of fins extending radially outward. The thickness of the fins The outer edge of the outer friction plate is provided with a plurality of outer claws extending radially outward, 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 penetrating outer 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 connected to the corresponding outer grooves in a front-rear sliding manner, and the inner cylindrical surface of the outer shell is provided with a plurality of axially penetrating inner grooves, and the outer The 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 with the corresponding inner groove for front and rear sliding. The piston rod and the rear cover limit the brake assembly axially from the front and rear directions respectively. 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 from 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 arranged 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, and a retaining ring and an O-ring are arranged 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] An annular groove is arranged on the front end surface of the piston of the piston cylinder, and the rear part of the spring is installed in the annular groove.

[0011] The large torque hydraulic brake for coal mining machine adopts 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.

[0012] 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.

[0013] 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. A radially outwardly 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. 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-to-back sliding manner. A seal is provided between the smooth rod portion and the sliding contact surface of the plug.

[0014] 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 in the initial installation and brake holding state.

[0015] When initially installed and in the brake state, the warning mark is 3-5 mm away from the front end surface of the cylinder.

[0016] The cylinder barrel may include a cylinder body and an end cover fixed at an open front end of the cylinder body, and the screw plug mounting through hole is arranged on the end cover.

[0017] The beneficial effects of the present invention 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 a large amount of heat caused by the continuous shearing of the too 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.

[0019] The material of the wave spring sheet is usually 65Mn. Compared with rubber material, it can withstand the high temperature of the coal mining machine brake during operation, 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, thus 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 oil injection 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 A schematic diagram of the structure of the wave spring sheet;

[0030] Figure 8 for Figure 7 Side view of

[0031] Fig. 9 for Figure 2 The assembly diagram of the high-torque hydraulic brake for the coal mining machine and the high-speed shaft of the traction drive system is shown.

[0032] Reference numerals:

[0033] 1. Piston; 2. Cylinder body; 3. Spring; 4. Spline sleeve; 5. Outer shell; 6. Inner friction plate; 61. Main body of the inner friction plate; 62. Inner 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] like Figure 1-9 As shown, the present invention discloses a high-torque hydraulic brake (referred to as brake) for coal mining machines, which belongs to a disc brake and includes a housing 5, a rear cover 8, a spline sleeve 4, a single-rod piston cylinder and a brake assembly. The front and rear chambers of the single-rod piston cylinder are a rodless chamber and a rod chamber, respectively. A spring 3 is provided in the rodless chamber, and the spring is kept in a compressed state. The rod chamber is connected to a low-pressure 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 a first long bolt 14. A circular groove is provided on the end face of the extended end of the piston rod of the single-rod piston cylinder, and 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 and the rear cover are axially and radially positioned by a stopper, and the spline sleeve is limited from moving backward by a retaining ring installed on the 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 both annular. The inner and outer friction plates are alternately stacked in the axial direction. In the radial direction, the inner and outer friction plates are coaxial and their main bodies are partially or completely overlapped. The annular disk surfaces of the main bodies of the adjacent inner and outer friction plates form a group of friction pairs. The brake has multiple groups 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) inner side claws 62 extending radially inward. 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 drawings) fins 63 extending radially outward. The thickness of the fins is less than the thickness of the main body of the inner friction plate, and the fins are arranged in the center relative to the main body of the inner friction plate in the thickness direction. That is, there is a 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. In order to simplify the expression, the distance can be referred to as the shoulder width w. The outer edge of the main body of the outer friction plate is provided with a plurality of (for example, 6) outer side claws extending radially outward. 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 penetrating outer 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 connected to the corresponding outer grooves for sliding forward and backward. The inner cylindrical surface of the outer shell is provided with a plurality of axially penetrating inner grooves, the outer friction plate is installed in the inner hole of the outer shell, and the outer claws are embedded in the inner grooves one by one and connected to the corresponding inner grooves for sliding forward and backward. The outer grooves are used to limit the rotation of the outer friction plate, and the inner grooves are used to make the spline sleeve and the inner friction plate rotate or stop synchronously. The outer grooves and the inner grooves are preferably evenly distributed along the circumference of their respective axes. The piston rod and the rear cover 8 of the single-rod piston cylinder axially limit the brake assembly from the front and rear directions respectively.

[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 fin of each inner friction sheet and the adjacent outer friction sheet. 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 drawings, 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 equipped with two brakes, which are respectively installed at the left and right traction shafts (i.e., the high-speed shaft 13 of the traction part transmission system) of the coal mining machine (see Fig. 9), specifically, the external spline at the end of the high-speed shaft is spline-connected with the internal spline on the spline sleeve. When installing, first put the entire brake on the high-speed shaft gear spline, and then fix it to the traction part housing with 12 second long bolts 15. In order to avoid accidentally removing the first long bolt when removing the brake as a whole, mark the head of the first long bolt. In the parking state, there is oil return to the rod chamber, and the piston 1 of the piston cylinder moves backward under the thrust of the spring 3. The axial pressure of the spring 3 presses the inner and outer friction plates against each other through the piston, and the brake is engaged. In the engaged state, the adjacent inner and outer friction plates are in close contact and have no relative rotation. The spline sleeve is also stationary with the inner friction plate relative to the outer shell, applying a braking torque to the high-speed shaft, and the wave spring sheet 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 sheet is very small, it does not affect the braking torque. When the coal mining machine is ready to start moving, oil enters the rod chamber, and the piston 1 moves forward under the action of liquid pressure to overcome the spring force of spring 3, causing the axial pressure between the adjacent inner and outer friction plates to be cancelled, the brake is released, and the spline sleeve drives the inner friction plate to rotate relative to the outer shell, thus not affecting the rotation of the high-speed shaft.

[0039] Since the free height of the wave spring sheet is greater than the shoulder width w, once the axial pressure is removed, the wave spring sheet will axially stretch to restore the free height, and will evenly bounce the adjacent inner and outer friction plates apart, 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, thereby preventing a large amount of heat caused by the continuous shearing of the too 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 high during operation, especially the local temperature between the friction plates is higher, which may reach more than 100 degrees. The material of the wave spring sheet is usually 65Mn, which is not easy to age, deform or even burn out compared with rubber material, and is more reliable in operation and has a longer service life.

[0041] The wave spring sheet is naturally positioned in the annular space surrounded by the outer cylindrical surface of the inner friction sheet, the fin of the inner friction sheet and the adjacent outer friction sheet. The structure is very simple and easy to assemble. The force of the wave spring to open the outer friction sheet is applied to the outer friction sheet in multiple areas evenly distributed on the entire annular plane, so that the axial force of the outer friction sheet is more uniform, and there will be no tilting or jamming.

[0042] The wave spring in the figure is 0.4mm thick, with a wavy disk surface and a free height of 1.0mm.

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

[0044] An annular sealing groove is 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, and 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, that is, both are on the low-pressure side of the corresponding O-ring. Compared with the sealing structure with only the O-ring, the retaining ring can prevent the pressure oil from squeezing the O-ring into the gap between the piston and the piston rod and the cylinder barrel, thereby extending the service life of the O-ring. The O-ring is preferably made of fluororubber sealing material, which has better heat resistance, can adapt to high-temperature working environment, and is not easy to age and deform.

[0045] The cylinder 2 and the housing 5 can be positioned axially and radially by means of a circular stop. The housing 5 and the rear cover 8 can also be positioned axially and radially by means of a circular stop. In the accompanying drawings, the housing is a ring without a stop, and a circular outer stop is provided on the rear end face of the cylinder and the front end face of the rear cover respectively. A sealing gasket is provided at the joint between the rear end face of the cylinder and the front end face of the rear cover and the housing.

[0046] An annular groove is arranged on the front end surface of the piston, and the rear part of the spring is installed in the annular groove. As a part of the spring is embedded in the piston, the axial dimension 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 generate sparks. Specifically, the space surrounded by the piston cylinder, the housing, 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, the gear oil in the traction housing flows through the gap between the spline sleeve and the high-speed shaft and enters the friction chamber through the above-mentioned channel, and the gear oil is used as the working oil of the friction plate.

[0048] It is preferred to maintain the main spacing between adjacent inner and outer friction plates at 0.3-0.5 mm when the brake is released. This can not only avoid abnormal heating caused by too thin oil film sheared during rotation of the inner friction plate, but also avoid insensitive braking caused by too thick oil film between the inner and outer friction plates.

[0049] The brake also preferably includes a warning screw 12 and a screw plug 10. The rear end of the warning screw is a threaded portion, the front part is a smooth rod portion, and there is a radially outwardly protruding flange between the threaded portion and the smooth rod portion. In the embodiment shown in the attached drawings, the threaded portion adopts an M16 thread. The middle part of the piston is provided with a central threaded hole that passes through the front and back, that is, the central threaded hole is connected to 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 screw-in depth of the threaded portion is determined by the flange, and the warning screw will move back and forth with the piston. A screw plug installation through hole is provided on the front wall of the cylinder barrel, and the screw plug is installed in the screw plug installation through hole. The smooth rod portion of the warning screw passes through the screw plug and is connected to the screw plug in a forward and backward sliding manner. A seal is provided between the sliding contact surface of the smooth rod portion and the screw plug to prevent coal slag and water from entering the brake, and also to prevent the internal oil of the brake from leaking out. The seal in the attached drawings is an O-ring, which is arranged in an annular sealing groove opened along the circumferential direction on the cylindrical surface of the smooth rod portion.

[0050] The cylindrical surface of the polished rod portion is preferably provided with a warning mark, for example, it can be a dot, a line or a full-circle mark set on the cylindrical surface of the polished rod portion. When initially installed and in the brake state, the warning mark is located in front of the front end face of the cylinder barrel. As the inner and outer friction plates wear, the piston will move further and further backward when the brake is engaged, and the position of the warning mark will also be closer and closer to the cylinder barrel. When they are close to a certain extent, the inner and outer friction plates have reached the maximum allowable wear amount. 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 degree of proximity to which the inner and outer friction plates are considered to need to be replaced can be determined based on the actual specific circumstances. In this embodiment, when it is found that the position of the warning mark sinks into the front end face of the cylinder barrel, it is considered that the inner and outer friction plates need to be replaced.

[0051] When initially installed and in the brake state, the warning mark is preferably 3-5 mm away from the front end surface of the cylinder, and is 3 mm in the embodiment shown in the drawings, that is, the inner and outer friction plates need to be replaced when the total wear reaches 3 mm.

[0052] The setting of the warning screw can truly reflect the wear condition of the friction plate, making it convenient to grasp the changes in the wear amount of the friction plate at any time underground, and solve the problem that manual detection is difficult or the detection error is large due to the harsh working environment and the installation location, resulting in excessive wear of the inner and outer friction plates not being discovered and corrected in time, leading to insufficient braking torque and even causing safety accidents such as slipping.

[0053] The cylinder barrel may include a cylinder body 2 and an end cover 11 fixed at the front end opening of the cylinder body, the end cover serving as the front wall of the cylinder barrel. The screw plug installation through hole is arranged on the end cover.

[0054] The central threaded hole can be used to inject oil into the friction chamber. The injection of oil into the friction chamber is mainly used in the following two occasions: one is before installation, when the brake is tested at the factory, it is necessary to inject oil into the friction chamber; the other is when the coal mining machine is on a large-angle working surface or has a certain direction angle, it is necessary to check whether there is gear oil flowing into the friction chamber of the brake on the higher end traction part before starting the coal mining machine. If there is no oil, it also needs to be injected.

[0055] A plurality of through holes extending forward and backward may also be provided around the central threaded hole on the piston. In the figure, the plurality of through holes are evenly distributed along the circumference. On the one hand, the through holes may also be used for oil injection, thereby speeding up the oil injection speed. On the other hand, when the brake is integrally mounted on the gear spline, the friction chamber is a closed chamber, and the through holes may be used for exhaust.

[0056] The central threaded hole can also be used to release the brake mechanically. The specific operation is: first remove the screw plug 10, put a flat washer on the front end surface of the cylinder or the end cover, and screw a bolt (M16) through the flat washer into the central threaded hole of the piston until the bolt head rests on the flat washer. Continue to tighten the bolt, the piston is lifted, and the brake is released immediately. This operation is convenient and reliable. When the hydraulic brake system or the brake fails and needs to be repaired, this method can be used to release the brake.

[0057] The large-torque hydraulic brake for the coal mining machine has a compact structure, a static braking torque of up to 1600 N·m, and a dynamic braking torque of up to 800 N·m, and can meet the braking needs of a coal mining machine weighing 230 tons.

[0058] The front and back mentioned in this article correspond to Figure 2 The left and right in the perspective are for the convenience of expression, not for limiting the absolute direction.

Claims

1. A high torque hydraulic brake for a coal mining machine, characterized in that: 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 arranged in the rodless chamber, and the spring 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. 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. There is a through hole between the spline sleeve and the rear cover. The stopper is used for axial and radial positioning, and the spline sleeve is limited to move 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 main bodies are kept partially or completely overlapped. The inner edge of the main body of the inner friction plate is provided with a plurality of inner side claws extending radially inward, and the outer cylindrical surface of the main body of the inner friction plate is provided with a plurality of fins extending radially outward, and the thickness of the fins is less than the main body of the inner friction plate. The thickness of the body, and the fin is arranged in the center 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 outer claws extending radially outward. 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 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 front and rear sliding. The inner cylindrical surface of the shell is provided with a plurality of axially penetrating inner grooves. The outer friction plate is installed The outer claws are embedded in the inner grooves one by one and are connected to the corresponding inner grooves for front and rear sliding. The piston rod and the rear cover limit the brake assembly axially from the front and rear directions respectively. 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 from 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 coal mining machine according to claim 1, characterized in that: The spring is a disc spring.

3. The high torque hydraulic brake for coal mining machine according to claim 1, characterized in that: An annular sealing groove is respectively arranged 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, and a retaining ring and an O-ring are arranged 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 coal mining machine according to claim 1, characterized in that: An annular groove is arranged on the front end surface of the piston of the piston cylinder, and the rear part of the spring is installed in the annular groove.

5. The high torque hydraulic brake for 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.

6. The high torque hydraulic brake for coal mining machine according to claim 1, 2, 3, 4 or 5, 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.

7. The high torque hydraulic brake for 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 outwardly protruding flange is 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 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 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-to-back sliding manner, and a seal is provided between the smooth rod portion and the sliding contact surface of the plug.

8. The high torque hydraulic brake for coal mining machine according to claim 7, characterized in that: A warning mark is arranged 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 in the initial installation and brake holding state.

9. The high torque hydraulic brake for coal mining machine according to claim 8, characterized in that: When initially installed and in the brake state, the warning mark is 3-5 mm away from the front end surface of the cylinder.

10. The high torque hydraulic brake for coal mining machine according to claim 8, characterized in that: The cylinder barrel comprises a cylinder body and an end cover fixed at the front end opening of the cylinder body, and the screw plug mounting through hole is arranged on the end cover.

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