A high-speed, high-load flexible drive motor

Abstract

The present invention relates to the technical field of motor technology, and specifically discloses a high-speed, high-load flexible drive motor, comprising a casing, with an upper end cover and a lower end cover detachably connected at both ends of the casing; a connecting seat, a transition sleeve, and a large-load bearing seat are arranged on the upper end cover; a rotor is arranged in the casing, and a flexible drive shaft is connected between the rotor and the large-load bearing seat; the motor can effectively reduce the vibration and noise generated when the motor runs at high speed by arranging the flexible drive shaft and the large-load bearing seat, thereby improving the safety of use; the transition sleeve and the upper end cover are threadedly fastened, which can form a seal to prevent foreign matter from entering the bearing chamber and prevent the motor from hitting the flexible drive shaft during transportation or handling; the connecting seat can be pressed against the upper end cover to form a skirt seat, which is used to connect an external sensor and block axial foreign matter from entering the interior of the motor; the two axle pins of the large-load bearing seat are connected to the main shaft seat body by interference fit to form an umbrella-shaped structure, which protects the flexible drive shaft.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a high-speed and high-load flexible drive motor. Background Art

[0002] During the operation of a high-speed motor, the motor drive shaft directly drives the rotor to rotate. It has high rigidity and bears a large load, which is prone to vibration and noise, affecting the overall performance of the motor. In addition, when running at high speed, the rigid shaft may not be able to withstand the strength and break, which poses a certain risk of use.

[0003] A Chinese patent document CN220754456U discloses a high-voltage and high-speed motor, comprising a housing, a magnetic steel, a motor rotor and a motor stator; the outer wall of the housing is provided with more than two heat-conducting grooves; the motor rotor is located inside the housing, and the motor rotor is in a columnar structure as a whole; an annular protrusion is provided on the outer wall of the middle axial part of the motor rotor, and the annular protrusion is provided with a mounting groove, and there are more than two mounting grooves, and the two mounting grooves are distributed circumferentially around the axis of the motor rotor, and the two axial ends of the motor rotor respectively pass through the side walls of the opposite ends of the housing, and the motor rotor is connected to the side wall of the housing through a bearing; the magnetic steel matches the mounting groove, and the magnetic steel is fixed in the mounting groove; the motor stator is fixed to the inside of the housing, and the motor stator is in a hollow ring shape as a whole, and the motor rotor is sleeved in the annular center of the motor stator, and the axis of the motor rotor and the motor stator are in the same direction, and a preset gap is provided between the outer wall of the motor rotor and the inner wall of the motor stator, which can enhance the connection stability of the magnetic steel and the rotor assembly.

[0004] However, the above disclosed technical content only solves the problem of heat conduction and heat dissipation of the motor, and does not optimize the problem that the transmission shaft is prone to vibration, noise and breakage.

[0005] Therefore, we provide a high-speed and large-load flexible drive motor to solve the above problems. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] The problem to be solved by the present invention is to provide a high-speed and heavy-load flexible drive motor to overcome the defects in the prior art.

[0008] (II) Technical solution

[0009] In order to solve the technical problem, the present invention provides a high-speed and large-load flexible drive motor, comprising a casing, wherein both ends of the casing are detachably connected with an upper end cover and a lower end cover;

[0010] A connecting seat, wherein the connecting seat and the upper end cover are detachably connected;

[0011] A transition sleeve, the upper end cover and the connecting seat are provided with connecting holes connected to the transition sleeve, and a through hole is provided in the transition sleeve; the transition sleeve is made of stainless steel, with flat ends on both sides, which is used for fastening with the upper end cover thread, and its main function is to protect the flexible drive shaft; first, it can form a seal to prevent foreign matter from entering the bearing chamber; second, it can prevent the motor from hitting the flexible drive shaft during transportation or handling; pressing the connecting seat onto the upper end cover can form a skirt seat, which is used to connect external sensors and block axial foreign matter from entering the motor, thereby providing good protection for the motor.

[0012] A large-load bearing seat, the large-load bearing seat is rotatably connected to the transition sleeve, and an axle pin is arranged on the large-load bearing seat; the large-load bearing seat is composed of a main shaft seat body and an axle pin, and plays a role in bearing large loads (enlarging the bearing cross-section of the flexible drive shaft), and the torque of the motor is transmitted through the inclined surface on the main shaft seat body and two axle pins, the axle pin is made of CrMo alloy steel after quenching and tempering treatment, the main shaft seat body is made of stainless steel, the thread is used to tighten the external load, and the two axle pins are connected to the main shaft seat body by interference fit; at the same time, the large-load bearing seat has an umbrella-shaped structure, which also plays a role in protecting the flexible drive shaft.

[0013] A rotor, the rotor being rotatably connected to the upper end cover and the lower end cover;

[0014] A flexible drive shaft, one end of which is connected to the rotor, and the other end of which is connected to the large-load bearing seat; the arrangement of the flexible drive shaft and the large-load bearing seat of the motor can effectively reduce the vibration and noise generated when the motor runs at high speed, thereby improving safety in use.

[0015] An adjusting spring is located between one end of the rotor and the upper end cover.

[0016] Furthermore, the through hole diameter of the transition sleeve is larger than the shaft diameter of the flexible drive shaft.

[0017] Furthermore, the casing is made of cast iron, and ventilation is provided on both sides of the casing, which is beneficial to the heat dissipation of the motor (heat dissipation of the stator coil).

[0018] Furthermore, a matching hole is provided on the upper end cover, the right end of the rotor is connected to the second bearing, a gasket is provided between the second bearing and the adjustment spring, the left end of the rotor is connected to the first bearing, and a left balance block and a right balance block are respectively installed at both ends of the rotor; the adjustment spring is used to adjust the bearing clearance, which is beneficial to reduce the vibration of the bearing during high-speed rotation; the left balance block and the right balance block of the rotor are used to correct the imbalance of the rotor, so that the motor can maintain stable operation during high-speed rotation.

[0019] Furthermore, the transition sleeve is made of stainless steel, and both ends of the transition sleeve are arranged with flat ends, and the connecting seat is pressed on the upper end cover to form a skirt seat.

[0020] Furthermore, the large-load bearing seat is composed of a main shaft seat body and an axle pin. The torque of the motor is transmitted through the inclined surface on the main shaft seat body and the two axle pins. The axle pin is made of CrMo alloy steel, and the main shaft seat body is made of stainless steel. The two axle pins are connected to the main shaft seat body by interference fit, and the large-load bearing seat has an umbrella-shaped structure.

[0021] Furthermore, the lower end cover is installed with a speed sensor, and the speed sensor measures the speed of the motor using the Hall principle through a magnetic steel installed at the bottom of the rotor.

[0022] Furthermore, a six-axis vibration sensor is installed at the bottom of the lower end cover to monitor the vibration condition during the operation of the motor.

[0023] Furthermore, one end of the flexible drive shaft has a first truncated cone portion, the other end of the flexible drive shaft has a second truncated cone portion, the right end of the rotor has a first tapered hole, the heavy load bearing seat has a second tapered hole, the first truncated cone portion is fixed in the first tapered hole, and the second truncated cone portion is fixed in the second tapered hole; the taper matching structure can limit the axial and radial directions to avoid movement. At the same time, it can also play a role in expanding the contact surface and reducing the force intensity.

[0024] Furthermore, the taper of the first truncated cone portion and the second truncated cone portion is 1°10′.

[0025] (III) Beneficial effects

[0026] Compared with the prior art, the high-speed and high-load flexible drive motor provided by the present invention has the following beneficial effects:

[0027] 1. The upper end cover and the connecting seat of the present invention are provided with connecting holes connected to the transition sleeve, and a through hole is provided in the transition sleeve; the transition sleeve is made of stainless steel, with flat ends on both sides, which is used for fastening with the upper end cover thread, and its main function is to protect the flexible drive shaft; first, it can form a seal to prevent foreign matter from entering the bearing chamber; second, it can prevent the motor from hitting the flexible drive shaft during transportation or handling; pressing the connecting seat onto the upper end cover can form a skirt seat, which is used to connect an external sensor and block axial foreign matter from entering the motor, thereby providing good protection for the motor.

[0028] 2. The large-load bearing seat of the present invention is rotatably connected to the transition sleeve, and an axle pin is arranged on the large-load bearing seat; the large-load bearing seat is composed of a main shaft seat body and an axle pin, and plays a role of bearing large loads (enlarging the bearing cross-section of the flexible drive shaft), and the torque of the motor is transmitted through the inclined surface on the main shaft seat body and two axle pins. The axle pin is made of CrMo alloy steel after quenching and tempering treatment, and the main shaft seat body is made of stainless steel. The thread is used to tighten the external load, and the two axle pins are connected to the main shaft seat body by interference fit; at the same time, the large-load bearing seat has an umbrella-shaped structure, which also plays a role of protecting the flexible drive shaft.

[0029] 3. The flexible drive shaft of the present invention has one end connected to the rotor, and the other end connected to the large-load bearing seat; one end of the flexible drive shaft has a first truncated cone portion, and the other end of the flexible drive shaft has a second truncated cone portion. The right end of the rotor has a first tapered hole, and the large-load bearing seat has a second tapered hole. The first truncated cone portion is fixed in the first tapered hole, and the second truncated cone portion is fixed in the second tapered hole. The taper matching structure can limit the axial and radial directions to avoid movement. At the same time, it can also expand the contact surface and reduce the force intensity. The setting of the flexible drive shaft and the large-load bearing seat of this motor can effectively reduce the vibration and noise generated when the motor runs at high speed, and improve the safety of use.

[0030] 4. The casing of the present invention is made of cast iron, and ventilation is provided on both sides of the casing, which is beneficial to the heat dissipation of the motor (heat dissipation of the stator coil). The adjustment spring is used to adjust the bearing clearance, which is beneficial to reducing the vibration of the bearing during high-speed rotation; the left balance block and the right balance block of the rotor are used to correct the imbalance of the rotor, so that the motor can maintain stable operation during high-speed rotation. The lower end cover is equipped with a speed sensor, which measures the speed of the motor using the Hall principle through the magnet installed at the bottom of the rotor. A six-axis vibration sensor is installed at the bottom of the lower end cover to monitor the vibration condition of the motor during operation, so as to achieve real-time detection of the motor operation status and timely feedback it to the control center, thereby reducing the excessive damage of the motor due to failure to shut down in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a first stereoscopic diagram of a high-speed and large-load flexible drive motor of the present invention;

[0033] Figure 2A second stereoscopic diagram of a high-speed, high-load flexible drive motor according to the present invention;

[0034] Figure 3 An exploded diagram of a high-speed, high-load flexible drive motor according to the present invention;

[0035] Figure 4 It is a schematic diagram showing another perspective of an exploded view of a high-speed and high-load flexible drive motor of the present invention;

[0036] Figure 5 Schematic diagram of the separation of the upper end cover and the connecting seat of a high-speed and high-load flexible drive motor of the present invention Figure 1 ;

[0037] Figure 6 Schematic diagram of the separation of the upper end cover and the connecting seat of a high-speed and high-load flexible drive motor of the present invention Figure 2 ;

[0038] Figure 7 Schematic diagram of the separation of the lower end cover and the housing of a high-speed, high-load flexible drive motor of the present invention Figure 1 ;

[0039] Figure 8 Schematic diagram of the separation of the lower end cover and the housing of a high-speed, high-load flexible drive motor of the present invention Figure 2 ;

[0040] Fig. 9 This is a schematic diagram of the connection between the flexible drive shaft and the rotor of a high-speed and high-load flexible drive motor of the present invention;

[0041] Fig.10 A cross-sectional view of a high-speed, high-load flexible drive motor according to the present invention;

[0042] The names of the components corresponding to the various figure marks in the figure are: 1. casing; 2. upper end cover; 201. connecting hole; 202. matching hole; 3. lower end cover; 4. six-axis vibration sensor; 5. transition sleeve; 501. connecting seat; 6. large load bearing seat; 7. first bearing; 8. rotor; 801. right end; 802. left end; 803. left balance block; 804. right balance block; 9. flexible drive shaft; 10. second bearing; 11. adjustment spring; 12. washer; 13. shaft pin. DETAILED DESCRIPTION

[0043] The present application is described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0045] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0046] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0047] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0048] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0049] See also Figures 1 to 10 The present invention provides a high-speed, high-load flexible drive motor, comprising a housing 1, with an upper end cover 2 and a lower end cover 3 detachably connected at both ends of the housing 1;

[0050] A connecting seat 501, the connecting seat 501 and the upper end cover 2 are detachably connected;

[0051] The transition sleeve 5, the upper end cover 2 and the connecting seat 501 are provided with a connecting hole 201 connected to the transition sleeve 5, and a through hole is provided in the transition sleeve 5; the transition sleeve 5 is made of stainless steel with flat ends on both sides for fastening with the threads of the upper end cover 2, and its main function is to protect the flexible drive shaft 9; first, it can form a seal to prevent foreign matter from entering the bearing chamber; second, it can prevent the motor from hitting the flexible drive shaft 9 during transportation or handling; pressing the connecting seat 501 onto the upper end cover 2 can form a skirt seat, which is used to connect external sensors and block axial foreign matter from entering the interior of the motor, thereby providing good protection for the motor.

[0052] A large-load bearing seat 6 is rotatably connected to the transition sleeve 5, and an axle pin 13 is arranged on the large-load bearing seat 6; the large-load bearing seat 6 is composed of a main shaft seat body and an axle pin 13, and plays a role in bearing large loads (enlarging the bearing cross-section of the flexible drive shaft 9), and the torque of the motor is transmitted through the inclined surface on the main shaft seat body and the two axle pins 13, and the axle pins 13 are made of 40CrMo alloy steel after quenching and tempering treatment, and the main shaft seat body is made of stainless steel. The thread is used to tighten the external load, and the two axle pins 13 are connected to the main shaft seat body by interference fit; at the same time, the large-load bearing seat 6 has an umbrella-shaped structure, which also plays a role in protecting the flexible drive shaft 9.

[0053] The rotor 8 is rotatably connected to the upper end cover 2 and the lower end cover 3;

[0054] A flexible drive shaft 9, one end of which is connected to the rotor 8, and the other end of which is connected to the large-load bearing seat 6; the setting of the flexible drive shaft 9 and the large-load bearing seat 6 of the motor can effectively reduce the vibration and noise generated when the motor runs at high speed, thereby improving the safety of use.

[0055] The adjusting spring 11 is located between one end of the rotor 8 and the upper end cover 2 .

[0056] See also Figures 3 to 10 The through hole diameter of the transition sleeve 5 is larger than the shaft diameter of the flexible drive shaft 9. The casing 1 is made of cast iron. Ventilation is provided on both sides of the casing 1, which is beneficial to the heat dissipation of the motor (heat dissipation of the stator coil). A matching hole 202 is also provided on the upper end cover 2. The right end 801 of the rotor 8 is connected to the second bearing 10. A gasket 12 is provided between the second bearing 10 and the adjustment spring 11. The left end 802 of the rotor 8 is connected to the first bearing 7. The left balance block 803 and the right balance block 804 are respectively installed at both ends of the rotor 8; the adjustment spring 11 is used to adjust the bearing clearance, which is beneficial to reduce the vibration of the bearing during high-speed rotation; the left balance block 803 and the right balance block 804 of the rotor 8 are used to correct the imbalance of the rotor 8, so that the motor can maintain stable operation during high-speed rotation. The transition sleeve 5 is made of stainless steel, and the two ends of the transition sleeve 5 are flat. The connecting seat 501 is pressed on the upper end cover 2 to form a skirt seat.

[0057] See also Figures 2 to 10 The large-load bearing seat 6 is composed of a main shaft seat body and an axle pin 13. The torque of the motor is transmitted through the inclined surface on the main shaft seat body and two axle pins 13. The axle pin 13 is made of 40CrMo alloy steel, and the main shaft seat body is made of stainless steel. The two axle pins 13 are connected to the main shaft seat body by interference fit. The large-load bearing seat 6 is an umbrella-shaped structure. The lower end cover 3 is equipped with a speed sensor. The speed sensor uses the Hall principle to measure the speed of the motor through the magnetic steel installed at the bottom of the rotor 8. A six-axis vibration sensor 4 is installed at the bottom of the lower end cover 3 to monitor the vibration condition of the motor during operation. One end of the flexible drive shaft 9 has a first truncated cone portion, and the other end of the flexible drive shaft 9 has a second truncated cone portion. The right end 801 of the rotor 8 has a first tapered hole, and the large-load bearing seat 6 has a second tapered hole. The first truncated cone portion is fixed in the first tapered hole, and the second truncated cone portion is fixed in the second tapered hole; the tapered matching structure can limit the axial and radial directions to avoid movement. At the same time, it can also play a role in expanding the contact surface and reducing the force intensity. The taper of the first truncated cone part and the second truncated cone part is 1°10′.

[0058] This embodiment provides a high-speed, high-load flexible drive motor:

[0059] The transition sleeve 5 is made of stainless steel with flat ends on both sides, and is used for fastening with the threads of the upper end cover 2. Its main function is to protect the flexible drive shaft 9. First, it can form a seal to prevent foreign matter from entering the bearing chamber. Second, it can prevent the motor from hitting the flexible drive shaft 9 during transportation or handling. Pressing the connecting seat 501 onto the upper end cover 2 can form a skirt seat, which is used to connect external sensors and block axial foreign matter from entering the interior of the motor, thereby providing good protection for the motor.

[0060] A large-load bearing seat 6 is rotatably connected to the transition sleeve 5, and an axle pin 13 is arranged on the large-load bearing seat 6; the large-load bearing seat 6 is composed of a main shaft seat body and an axle pin 13, which plays the role of bearing large loads and expanding the bearing cross-section of the flexible drive shaft 9. The torque of the motor is transmitted through the inclined surface on the main shaft seat body and the two axle pins 13. The axle pin 13 is made of 40CrMo alloy steel after quenching and tempering treatment, and the main shaft seat body is made of stainless steel. The thread is used to tighten the external load, and the two axle pins 13 are connected to the main shaft seat body by interference fit; at the same time, the large-load bearing seat 6 has an umbrella-shaped structure, which also plays a role in protecting the flexible drive shaft 9.

[0061] The arrangement of the flexible driving shaft 9 and the large-load bearing seat 6 of the motor can effectively reduce the vibration and noise generated when the motor runs at high speed, thereby improving the safety of use.

[0062] The same and similar parts between the various embodiments in this specification can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0063] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A high-speed, high-load flexible drive motor, characterized in that: include: A casing (1), wherein two ends of the casing (1) are detachably connected with an upper end cover (2) and a lower end cover (3); A connecting seat (501), wherein the connecting seat (501) and the upper end cover (2) are detachably connected; A transition sleeve (5), the upper end cover (2) and the connection seat (501) are provided with a connection hole (201) connected to the transition sleeve (5), and a through hole is provided in the transition sleeve (5); A large-load bearing seat (6), the large-load bearing seat (6) is rotatably connected to the transition sleeve (5), an axle pin (13) is arranged on the large-load bearing seat (6), the large-load bearing seat is composed of a main shaft seat body and the axle pin, plays a role in bearing a large load, and expands the bearing cross-section of the flexible drive shaft, the torque of the motor is transmitted through the inclined surface on the main shaft seat body and the two axle pins, the axle pin is made of CrMo alloy steel after quenching and tempering treatment, the main shaft seat body is made of stainless steel, the thread is used to tighten the external load, and the two axle pins are connected to the main shaft seat body by interference fit; at the same time, the large-load bearing seat has an umbrella-shaped structure, which also plays a role in protecting the flexible drive shaft; A rotor (8), the rotor (8) being rotatably connected to the upper end cover (2) and the lower end cover (3); A flexible drive shaft (9), one end of the flexible drive shaft (9) being connected to the rotor (8), and the other end of the flexible drive shaft (9) being connected to the large-load bearing seat (6); An adjusting spring (11), wherein the adjusting spring (11) is located between one end of the rotor (8) and the upper end cover (2).

2. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The through hole diameter of the transition sleeve (5) is larger than the shaft diameter of the flexible drive shaft (9).

3. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The casing (1) is made of cast iron, and ventilation holes are provided on both sides of the casing (1).

4. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The upper end cover (2) is also provided with a matching hole (202); the right end (801) of the rotor (8) is connected to a second bearing (10); a washer (12) is provided between the second bearing (10) and the adjustment spring (11); the left end (802) of the rotor (8) is connected to a first bearing (7); and a left balancing block (803) and a right balancing block (804) are respectively installed at both ends of the rotor (8).

5. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The transition sleeve (5) is made of stainless steel, and both ends of the transition sleeve (5) are arranged with flat ends. The connecting seat (501) is pressed tightly onto the upper end cover (2) to form a skirt seat.

6. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The heavy-load bearing seat (6) is composed of a main shaft seat body and an axle pin (13); the torque of the motor is transmitted through the inclined surface on the main shaft seat body and the two axle pins (13); the axle pins (13) are made of 40CrMo alloy steel, the main shaft seat body is made of stainless steel, the two axle pins (13) are connected to the main shaft seat body by interference fit, and the heavy-load bearing seat has an umbrella-shaped structure.

7. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: The lower end cover (3) is equipped with a speed sensor, which measures the speed of the motor using the Hall principle via a magnetic steel installed at the bottom of the rotor (8).

8. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: A six-axis vibration sensor (4) is installed at the bottom of the lower end cover (3).

9. The high-speed, high-load flexible drive motor according to claim 1, characterized in that: One end of the flexible drive shaft (9) has a first truncated cone portion, the other end of the flexible drive shaft (9) has a second truncated cone portion, the right end (801) of the rotor (8) has a first tapered hole, the heavy load bearing seat (6) has a second tapered hole, the first truncated cone portion is fixed in the first tapered hole, and the second truncated cone portion is fixed in the second tapered hole.

10. The high-speed, high-load flexible drive motor according to claim 9, characterized in that: The taper of the first truncated cone portion and the second truncated cone portion are both 1°10′.

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