A high speed clutch device

Abstract

The application provides a high-speed clutch device, which comprises a toothed oil cylinder, a piston, a clutch shell and a flange, a plurality of oil throwing holes are arranged on the clutch shell, a closed cavity is formed between the piston and the toothed oil cylinder, an oil inlet channel is arranged in the toothed oil cylinder, the oil inlet channel is communicated with the closed cavity, an axial speed relief through hole is arranged on the piston, a friction plate seat is arranged between a gear shaft and the clutch shell, a spring seat is arranged on one side of the toothed oil cylinder close to the gear shaft, a groove is arranged in the spring seat, and a reset spring is arranged in the groove. When the clutch needs to be discharged, the working oil pressure disappears, the working oil in the closed cavity is extruded under the action of the reset spring, the working oil in the closed cavity has a certain centrifugal pressure under the action of centrifugal force, the higher the rotating speed is, the greater the radius is, and the greater the centrifugal pressure is, so that the pressure oil forms a thrust to push away the friction plate group adhering to the piston, the working oil in the closed cavity is rapidly discharged, the piston is quickly reset, and the discharge is completed.

Description

TECHNICAL FIELD

[0001] The present application relates to the clutch technical field, specifically relates to a kind of high-speed clutch device. BACKGROUND

[0002] The wet friction clutch used in the marine gear box with forward and reverse direction changing function in prior art is generally composed of driving end with friction plate light piece and driven end with friction plate powder piece, and the driving end and driven end are separately supported by bearing, the bearing span is small, the clutch shaft system is rigid, when running empty, the driving end and driven end shaft system are relatively independent, which is conducive to the piece of friction plate and stable operation, and the clutch structure is widely used in medium and low speed marine gear box.

[0003] The reversing gear of traditional structure is arranged on the clutch housing, and the gear is installed on the clutch housing due to structural limitation, so that only a small number of oil throwing holes can be provided on the clutch housing for the discharge of lubricating / cooling oil of friction plate, the clutch has few discharge channels for lubricating / cooling oil of friction plate in general, and the lubricating / cooling oil cannot be discharged in time, which easily causes oil stirring and heating in the clutch at high speed.

[0004] The existing clutch oil cylinder is provided with a special speed relief valve for timely discharge of working oil in the oil cylinder after discharge, so that the piston resets and the friction plate pieces. The clutch speed relief valve cannot work normally due to excessive centrifugal force at high speed, and the working oil cannot be discharged from the oil cylinder in time at high speed, so that the piston cannot reset, the friction plate cannot be divided, and the clutch is easily burned. SUMMARY

[0005] The present application aims at the problem that the speed relief valve is installed on the oil cylinder of the clutch for discharge of working oil at present, but the speed relief valve can only be applied to low speed, and the speed relief valve cannot be opened and work normally under the action of high speed centrifugal force, which easily causes the clutch to be burned, and the problem that the lubricating / cooling oil discharge channel of the clutch structure is few, which easily causes oil stirring and heating at high speed, and provides a kind of high-speed clutch device.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The high-speed clutch device comprises a toothed oil cylinder, a piston, a clutch housing and a flange, one side of the clutch housing is connected with the toothed oil cylinder, the other side of the clutch housing is connected with the flange, a plurality of oil throwing holes are arranged on the clutch housing, a cavity is arranged on the side of the toothed oil cylinder close to the clutch housing, the piston is installed in the cavity, a closed cavity is formed between the piston and the toothed oil cylinder, an oil inlet channel is arranged in the toothed oil cylinder and communicates with the closed cavity, an axial speed relief through hole is arranged on the piston, a friction plate seat is installed between the gear shaft and the clutch housing, the friction plate seat is fixed through a pressing plate, a friction plate group is installed on the friction plate seat, a spring seat is installed on the side of the toothed oil cylinder close to the gear shaft, a groove is arranged in the spring seat, and a reset spring is installed in the groove.

[0008] Firstly, the gear is arranged on the oil cylinder to form a toothed oil cylinder, so that more oil throwing holes can be arranged on the clutch housing. Meanwhile, the speed relief through hole is arranged on the piston. When the clutch needs to be engaged, the working oil with a certain pressure enters the closed cavity formed by the piston and the toothed oil cylinder from the working oil inlet channel on the end surface of the toothed oil cylinder, and the piston is pushed to move under the pressure and finally the friction plate group is engaged. After the piston moves, the reset spring is further compressed. When the clutch needs to be disengaged, the working oil pressure disappears, the piston has a reset tendency under the action of the reset spring, and the working oil in the closed cavity is extruded to form a pressure. Under the action of the centrifugal force, the working oil in the closed cavity also has a certain centrifugal pressure. The higher the speed and the greater the radius, the greater the centrifugal pressure. The working oil discharged from the relief hole pushes away the friction plate close to the piston, so that the working oil in the closed cavity is quickly discharged and the piston is quickly reset to complete the disengagement.

[0009] Preferably, an end surface ring groove is arranged on the side of the piston close to the friction plate group. After the engagement, the end surface ring groove of the piston is blocked by the friction plate, the working oil cannot be discharged through the piston speed relief through hole, and a stable working oil pressure can be formed. When the piston and the friction plate group in contact cannot be separated, the end surface ring groove of the piston increases the oil area, thereby increasing the oil force, which helps to push away the friction plate group close to the piston, thereby discharging the working oil in the closed cavity. Compared with the traditional speed relief valve, the speed relief structure is simpler in structure, higher in reliability, and not limited by the speed, and is suitable for clutches running at any speed.

[0010] Preferably, a connecting hole is arranged on the circumference of the flange, a square through groove is arranged on the end surface of the flange, and the square through groove penetrates through the end surface of the flange. After the flange of the clutch housing is connected with the clutch housing, the square through groove forms an oil discharge channel communicating inside and outside.

[0011] Preferably, the piston is provided with a first sealing ring and a second sealing ring, the first sealing ring is matched with the first matching surface of the toothed oil cylinder, and the second sealing ring is matched with the second matching surface of the toothed oil cylinder.

[0012] Preferably, the toothed oil cylinder is provided with a stepped hole and a through hole, the stepped hole is connected with the clutch housing through a first torque transmission pin, and the through hole is connected with the clutch housing through a first fastening bolt, and the clutch housing and the flange are connected through a second torque transmission pin.

[0013] Preferably, the first torque transmission pin includes a large-diameter section and a small-diameter section, the small-diameter section is in interference fit with the clutch housing, the large-diameter section is in clearance fit with the toothed oil cylinder, the outer circumference of the small-diameter section is provided with an exhaust groove, the large-diameter section is internally provided with an internally threaded hole, and the first plug is mounted on the internally threaded hole. The inner hole of the small-diameter section of the stepped hole is a finished surface and is in interference fit with the first torque transmission pin. The inner hole of the large-diameter section is a non-finished surface and is in clearance fit with the torque transmission pin.

[0014] Preferably, the friction plate seat is internally provided with a slant hole, an axial blind hole and an oil injection small hole which are sequentially communicated, the inner wall of the friction plate seat is provided with a triangular annular groove, the starting point of the slant hole is located at the annular groove, the axial blind hole is parallel to the axial direction of the gear shaft, the oil injection small hole is vertically arranged at the axial blind hole, and the second plug is mounted on the side of the axial blind hole close to the toothed oil cylinder. The slant hole is arranged between the triangular annular groove and the axial blind hole, a certain number of oil injection small holes are arranged at each axial blind hole and communicated with the axial blind hole in the axial direction, and the lubricating / cooling oil sequentially passes through the triangular annular groove, the slant hole, the axial blind hole and the oil injection small hole to reach the friction plate set.

[0015] Preferably, the oil inlet channel includes a first channel, a second channel and a third channel, the first channel and the third channel are parallel to the axial direction of the gear shaft, the second channel is vertically arranged with the first channel, the top of the second channel penetrates to the outside of the toothed oil cylinder, and the third plug is mounted on the side of the second channel away from the first channel.

[0016] Preferably, the inner hole of the clutch housing is a involute internal spline, a certain number of spline teeth are uniformly removed along the circumferential direction of the involute internal spline, and the oil throwing hole is located on the involute internal spline from which the spline teeth are removed.

[0017] Compared with the prior art, the high-speed clutch device provided by the application is suitable for the clutch structure of a high-speed gear box of a ship with forward and reverse movement, the clutch driving end assembly and the clutch driven end assembly are respectively supported by bearings, the bearing span is small, and the clutch shaft system is rigid. The reversing gear is integrated on the oil cylinder to form a toothed oil cylinder, so that more oil discharge channels can be formed on the clutch housing, and a square through groove is arranged on the flange of the clutch housing for oil discharge. These innovative structures increase the oil discharge channels of the friction plate lubricating / cooling oil, and meet the oil discharge requirements of the friction plate lubricating / cooling oil at high speed. The application has simple structure and high reliability, and the rapid discharge through hole and the end face ring groove are arranged on the piston to rapidly discharge the working oil in the sealed cavity. When the clutch needs to be discharged, the working oil pressure disappears, the piston has a reset tendency under the action of the reset spring, and the working oil in the sealed cavity is extruded to form a centrifugal pressure. The higher the speed is, the greater the radius is, and the greater the centrifugal pressure is. The pressure oil enters the end face ring groove of the piston through the rapid discharge through hole to form a thrust to push away the friction plate attached to the piston, so that the working oil in the sealed cavity is rapidly discharged, the piston is quickly reset, and the discharge is completed. The structure is particularly suitable for high-speed clutches, and solves the problem that the speed discharge valve of the traditional clutch cannot normally work due to excessive centrifugal force at high speed. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a sectional view of the high-speed clutch device of the application;

[0019] Figure 2 FIG. 4 is a structure diagram of the toothed oil cylinder;

[0020] Figure 3 FIG. 6 is a structure diagram of the first torque transmission pin;

[0021] Figure 4 FIG. 8 is a structure diagram of the piston;

[0022] Figure 5 FIG. 10 is a structure diagram of the clutch housing;

[0023] Figure 6 FIG. 12 is a structure diagram of the flange;

[0024] Figure 7 FIG. 14 is a structure diagram of the friction plate seat.

[0025] Marked in the figure: 1 - first main drive end bearing, 2 - toothed oil cylinder, 2b - oil inlet channel, 2c - first matching surface, 2d - second matching surface, 2e - stepped hole, 2f - through hole, 3 - third plug, 4 - closed cavity, 5 - first plug, 6 - second plug, 7 - first torque transmission pin, 7a - chamfer, 7b - small diameter section, 7c - exhaust groove, 7d - large diameter section, 7e - internally threaded hole, 8 - first sealing ring, 9 - piston, 9a - end face ring groove, 9b - first sealing groove, 9c - quick release through hole, 9d - second sealing groove, 10 - clutch housing, 10a - oil throwing hole, 10c - internal spline, 11 - second torque transmission pin, 12 - flange, 12a - square through slot, 12b - connecting hole, 13 - friction plate seat, 13b - oil injection small hole, 13c - axial blind hole, 13d - inclined hole, 13e - annular groove, 14 - second main drive end bearing, 15 - gear shaft, 16 - driven end bearing, 17 - second driven end bearing, 18 - emergency bolt, 19 - spring seat bolt, 20 - first fastening bolt, 21 - second sealing ring, 22 - return spring, 23 - spring seat, 24 - friction plate group, 25 - second fastening bolt, 26 - pressure plate bolt, 27 - pressure plate, 28 - flat key. DETAILED DESCRIPTION

[0026] The present application will be described in detail below with reference to the drawings.

[0027] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0028] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0029] In the description of the present application, unless otherwise specified and limited, it should be noted that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection or electrical connection, it can be the communication between two elements, it can be direct connection or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by those skilled in the art according to the specific circumstances.

[0030] As Figure 1As shown, the application provides a high-speed clutch device, including a toothed oil cylinder 2, a piston 9, a clutch housing 10 and a flange 12, one side of the clutch housing 10 is connected with the toothed oil cylinder 2, the other side of the clutch housing 10 is connected with the flange 12, a plurality of oil throwing holes 10a are arranged on the clutch housing 10, which increases the oil discharge channel of the friction plate lubricating / cooling oil.

[0031] As shown in the drawings, Figure 5 The inner hole of the clutch housing 10 is an involute internal spline 10c, a certain number of spline teeth 10d are uniformly removed along the circumferential direction of the involute internal spline 10c, and the oil throwing hole 10a is located on the involute internal spline 10c from which the spline tooth 10d is removed. The oil throwing hole 10a makes the inside and outside of the clutch housing communicate, which is used for the discharge of the friction plate lubricating and cooling oil.

[0032] As shown in the drawings, Figure 2 The toothed oil cylinder 2 is provided with a cavity near one side of the clutch housing 10, and the piston 9 is installed in the cavity. The piston 9 is installed in the cavity, and a sealed cavity 4 is formed between the piston 9 and the toothed oil cylinder 2.

[0033] The toothed oil cylinder 2 is provided with an oil inlet channel 2b, which communicates with the sealed cavity 4. The oil inlet channel 2b includes a first channel, a second channel and a third channel, the first channel and the third channel are parallel to the axial direction of the gear shaft, and the second channel is perpendicular to the first channel. The top of the second channel penetrates to the outside of the toothed oil cylinder 2, and the third plug 3 is installed on the side away from the first channel of the second channel. The toothed oil cylinder 2 is provided with a stepped hole 2e and a through hole 2f, the stepped hole 2e is connected with the clutch housing 10 through the first torque transmission pin 7, the through hole 2f is connected with the clutch housing 10 through the first fastening bolt 20, and the clutch housing 10 and the flange 12 are connected through the second torque transmission pin 11. The toothed oil cylinder 2 is also provided with an emergency bolt 18.

[0034] As shown in the drawings, Figure 3 The first torque transmission pin 7 includes a large diameter section 7d and a small diameter section 7b, the small diameter section 7b is in interference fit with the clutch housing 10, the large diameter section 7d is in clearance fit with the toothed oil cylinder 2, the outer circumference of the small diameter section 7b is provided with an exhaust groove 7c, the large diameter section 7d is provided with an internal thread hole 7e, and the first plug 5 is installed on the internal thread hole 7e. The first torque transmission pin 7 is in interference fit with the small diameter section of the stepped hole 2e of the clutch housing 10 and the toothed oil cylinder 2, and the first torque transmission pin 7 is in clearance fit with the large diameter section of the stepped hole 2e. The end face of the small diameter section has a chamfer 7a, and the first torque transmission pin 7 has a guiding effect when it is inserted.

[0035] The friction plate seat 13 is installed between the gear shaft 15 and the clutch housing 10, and is fixed by the pressing plate 27, which is fixed on the gear shaft 15 by the pressing plate bolt 26. The friction plate group 24 is installed on the friction plate seat 13.

[0036] The friction plate seat 13 is fixedly connected with the gear shaft 15 through taper cooperation and the flat key 28, and is axially fixed by the pressing plate 27. The gear shaft is supported by three driven end bearings, as shown in the figure. Figure 1 The first driven end bearing 16 and the second driven end bearing 17 are installed on the gear shaft 15. The driving end is supported by the first driving end bearing 1 and the second driving end bearing 14. The driving end and the driven end assembly are separately supported by bearings, the bearing span is small, and the clutch shaft system is rigid. The friction plate group 24 is arranged between the clutch housing 10 and the friction plate seat 13. The friction plate group is composed of friction plate light sheets and friction plate powder sheets which are continuously distributed at intervals. The friction plate light sheets and the friction plate powder sheets are connected with the clutch housing 10 and the friction plate seat through involute splines, respectively. The piston 9 can move in the cavity of the toothed oil cylinder 2 to realize the compression of the friction plate light sheets and the friction plate powder sheets according to the change of the volume of the closed cavity.

[0037] As shown in the figure, Figure 7 The outer circle of the friction plate seat 13 is an involute outer spline, which is used to connect the friction plate light sheets. The friction plate seat 13 is internally provided with a slant hole 13d, an axial blind hole 13c and an oil injection small hole 13b which are sequentially communicated. The inner wall of the friction plate seat 13 is provided with a triangular annular groove 13e. The starting point of the slant hole 13d is located at the annular groove 13e. The axial blind hole 13c is parallel to the axial direction of the gear shaft 15 and is arranged along the circumference. The oil injection small hole 13b is vertically arranged at the axial blind hole 13c. The second plug 6 is installed on the side of the axial blind hole 13c close to the toothed oil cylinder 2. Lubricating / cooling oil reaches the friction plate group through the triangular annular groove 13e, the slant hole 13d, the axial blind hole 13c and the oil injection small hole 13b in sequence.

[0038] The toothed oil cylinder 2 is provided with a spring seat 23 on the side close to the gear shaft. The spring seat 23 is internally provided with a groove, and the reset spring 22 is installed in the groove.

[0039] As shown in the figure, Figure 4 The piston 9 is provided with a first sealing groove 9b and a second sealing groove 9d. The first sealing groove is internally provided with a first sealing ring 8, which cooperates with the first matching surface 2c of the toothed oil cylinder 2. The second sealing groove 9d is internally provided with a second sealing ring 21, which cooperates with the second matching surface 2d of the toothed oil cylinder 2. The side of the piston 9 close to the friction plate group 24 is provided with an end face annular groove 9a. The piston 9 is provided with a speed relief through hole 9c in the axial direction. A plurality of speed relief through holes 9c are arranged on the circumference of the piston 9.

[0040] The piston 9 is further provided with an end face ring groove 9a on the side away from the toothed oil cylinder 2. After the piston 9 is installed in the toothed oil cylinder 2, the quick release through hole 9c is communicated with the closed cavity 4, and the working oil in the closed cavity 4 can be discharged through the quick release through hole 9c. When the piston 9 and the friction plate group in contact with the piston 9 cannot be separated, the end face ring groove 9a of the piston 9 increases the oil area, thereby increasing the oil force, which helps to push away the friction plate group in contact with the piston 9, so as to discharge the working oil in the closed cavity. Compared with the traditional quick release valve, the quick release structure is simpler in structure, higher in reliability, and not limited by the speed, and is suitable for clutches running at any speed. The spring seat 23 is fixedly connected with the toothed oil cylinder 2 through the spring seat bolt 19, and the reset spring 22 is arranged between the piston 9 and the spring seat 23 for resetting the piston 9 after movement.

[0041] As shown in Figure 6 The flange 12 is provided with a connecting hole 12b on the circumference, and the end face of the flange 12 is provided with a square through groove 12a penetrating through the end face of the flange 12. The second torque transmission pin 11 and the second fastening bolt 25 pass through the connecting hole 12b to connect the flange 12 with the clutch housing 10.

[0042] The working oil quick release process of the clutch: when the clutch needs to be engaged or released, the working oil with a certain pressure enters the closed cavity 4 formed by the piston 9 and the toothed oil cylinder 2 from the end face of the toothed oil cylinder 2 through the working oil inlet channel 2b, and pushes the piston 9 to move and finally compresses the friction plate group 24 to complete the engagement or release. After the piston 9 moves, the reset spring 22 is further compressed. After the engagement or release, the end face ring groove 9a of the piston 9 is blocked by the friction plate group 24, the working oil cannot be discharged through the piston quick release through hole 9c, and a stable working oil pressure can be formed.

[0043] When the clutch needs to be disengaged, the working oil pressure disappears, the piston 9 has a resetting tendency under the action of the reset spring 22, and an extrusion pressure is formed on the working oil in the closed cavity 4. The working oil in the closed cavity 4 also has a certain centrifugal pressure under the action of the centrifugal force. The higher the speed and the greater the radius, the greater the centrifugal pressure. The pressure oil enters the end face ring groove 9a of the piston through the quick release through hole 9c, forms a thrust to push away the friction plate group 24 in contact with the piston, so that the working oil in the closed cavity is quickly discharged, and the piston is quickly reset to complete the disengagement.

[0044] The lubricating / cooling oil is thrown out through the oil throwing holes 10a on the clutch housing and the square through grooves 12a on the end face of the flange 12. Compared with the traditional clutch, the clutch has more oil throwing holes on the clutch housing and the flange is additionally provided with oil throwing channels, so that the clutch can be applied to marine clutches with low, medium or high operating speed

[0045] The above merely describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high speed clutch device, characterized by, It includes toothed oil cylinder (2), piston (9), clutch housing (10) and flange (12), one side of clutch housing (10) is connected with toothed oil cylinder (2), the other side of clutch housing (10) is connected with flange (12), a plurality of oil throwing holes (10a) are arranged on clutch housing (10), the side of toothed oil cylinder (2) close to clutch housing (10) is provided with a cavity, the piston (9) is installed in the cavity, the piston (9) and the toothed oil cylinder (2) form a sealed cavity (4), the toothed oil cylinder (2) is provided with an oil inlet channel (2b), the oil inlet channel (2b) is communicated with the sealed cavity (4), the piston (9) is provided with an axial speed relief through hole (9c), a friction plate seat (13) is installed between the gear shaft (15) and the clutch housing (10), the friction plate seat (13) is fixed by a pressing plate (27), the friction plate seat (13) is installed with a friction plate group (24), the side of the toothed oil cylinder close to the gear shaft is installed with a spring seat (23), the spring seat (23) is provided with a groove, the groove is installed with a return spring (22). The side of the piston (9) close to the friction plate group (24) is provided with an end face ring groove (9a). The circumference of the flange (12) is provided with a connecting hole (12b), the end face of the flange (12) is provided with a square through slot (12a), the square through slot (12a) penetrates the end face of the flange (12). The oil inlet channel (2b) includes a first channel, a second channel and a third channel, the first channel and the third channel are parallel to the axial direction of the gear shaft, the second channel is arranged perpendicular to the first channel, the top of the second channel penetrates the outside of the toothed oil cylinder (2), the side of the second channel away from the first channel is installed with a third plug (3).

2. The high speed clutch device of claim 1, wherein, The piston (9) is provided with a first sealing ring (8) and a second sealing ring (21), the first sealing ring (8) is matched with the first matching surface (2c) of the toothed oil cylinder (2); the second sealing ring (21) is matched with the second matching surface (2d) of the toothed oil cylinder (2).

3. The high speed clutch device of claim 1, wherein, The toothed oil cylinder (2) is provided with a stepped hole (2e) and a through hole (2f), the stepped hole (2e) is connected with the clutch housing (10) through a first torque transmission pin (7), the through hole (2f) is connected with the clutch housing (10) through a first fastening bolt (20), the clutch housing (10) and the flange (12) are connected through a second torque transmission pin (11).

4. The high speed clutch device of claim 3, wherein The first torque transmission pin (7) includes a large diameter section (7d) and a small diameter section (7b), the small diameter section (7b) is interference fit with the clutch housing (10), the large diameter section (7d) is clearance fit with the toothed oil cylinder (2), the outer circumference of the small diameter section (7b) is provided with an exhaust groove (7c), the large diameter section (7d) is provided with an internal thread hole (7e), the first plug (5) is installed on the internal thread hole (7e).

5. The high speed clutch device of claim 1, wherein, The friction plate seat (13) is internally provided with a slant hole (13d), an axial blind hole (13c) and an oil injection small hole (13b) which are communicated in sequence, the inner wall of the friction plate seat (13) is provided with a triangular annular groove (13e), the starting point of the slant hole (13d) is located at the annular groove (13e), the axial blind hole (13c) is parallel to the axial direction of the gear shaft (15), the oil small hole (13b) is vertically arranged on the axial blind hole (13c), and the second plug (6) is installed on the side close to the toothed oil cylinder (2) of the axial blind hole (13c).

6. The high speed clutch device of claim 1, wherein, The inner hole of the clutch housing (10) is a involute inner spline (10c), a certain number of spline teeth (10d) are uniformly removed along the circumferential direction of the involute inner spline (10c), and the oil throwing hole (10a) is located on the involute inner spline (10c) from which the spline teeth (10d) are removed.

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