TWI802450B - Motor - Google Patents

Abstract

The invention discloses a motor, which includes a motor body and a position sensing device. The motor body includes a stator, a rotor, and an outer casing. The mandrel of the stator has a first connection structure. The position sensing device includes a magnet module and a detection module. The magnet module includes a connecting assembly and a magnet. The connecting assembly includes a connecting seat and a locking member. The connecting seat includes a second connecting structure, and the second connecting structure is used for engaging with the first connecting structure. The connecting seat is fixed with the mandrel through the locking member. The detection module includes a base assembly and a circuit assembly. The base assembly is detachably arranged on the outer casing. The circuit assembly is detachably connected with the base assembly. When the mandrel rotates, the connecting seat and the magnet will rotate with the mandrel, and the sensor of the circuit component will sense the magnet to generate a position sensing signal correspondingly.

Description

motor

The invention relates to a motor, especially a motor with a position sensing module.

In the existing common motors equipped with position sensing modules, the relevant sensing modules are all installed inside the motor. In this way, during the manufacturing process, when relevant personnel want to adjust the sensing modules according to customer needs, they must Disassembly of the motor as a whole can only be adjusted, and in the process of disassembly, it is easy to cause damage to some components due to careless operation. In addition, the relevant personnel who purchase the motor will also encounter the same problem when they want to repair the sensing module.

The invention discloses a motor, which is mainly used to improve the existing motor with a position sensing module, because the position sensing module is arranged in the motor, which causes many inconveniences.

One embodiment of the invention discloses a motor, which includes: a motor body and a position sensing device. The main body of the motor includes: a stator, a rotor and an outer casing. The rotor includes a mandrel, and one end of the mandrel has a first connection structure; the stator and the rotor are arranged in the outer casing, and one end of the outer casing has an opening, and the first connection structure is exposed through the opening; the position sensing device includes: a magnet module and a detection module. The magnet module includes: a connecting component and an induction magnet. The connecting component includes a connecting seat and a locking member, the connecting seat includes a second connecting structure, the second connecting structure is used to engage with the first connecting structure, and the locking member detachably fixes the connecting seat and the mandrel, The connecting component can rotate with the mandrel; the induction magnet is fixed on the connecting seat; the detection module includes: a body component and a circuit component. The base assembly is detachably fixed on one side of the outer shell with an opening; the circuit assembly is detachably fixed on the base assembly, and a sensor of the circuit assembly is set facing the induction magnet; Among them, when the mandrel rotates, the connecting seat and the sensing magnet will rotate with the mandrel, and the sensor will sense the sensing magnet to generate a position sensing signal correspondingly.

To sum up, the motor of the present invention allows the position sensing device to be detachably installed on one end of the outer casing through the design of the first connection structure, the second connection structure, the magnet module, and the detection module, and relevant personnel The position sensing device can be easily disassembled.

In order to further understand the characteristics and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention, but these descriptions and drawings are only used to illustrate the present invention, rather than to make any statement on the scope of protection of the present invention. limit.

A: motor

A1: Motor body

1: Outer shell

10: shell body

101: ring side wall

102: bottom wall

1021: opening

1022: Keyhole

1023: wire hole

10A: storage space

11: End cap

2: Stator

3: rotor

30: mandrel

301: The first connection structure

302: Keyhole

4A: Bearing

4B: Bearing

A2: Position sensing device

5: Magnet module

51: Connection components

511: connection seat

5111: Second connection structure

5112: Keyhole

5113: tank

5114: side through hole

512: lock piece

513: Magnet holder

5131: fixed slot

5132: Operating hole

5133: external auxiliary structure

5134: internal auxiliary structure

513A: first end

513B: second end

513C: Bottom

52: induction magnet

6: Detection module

61: seat assembly

611: fixed seat

6111: Fixing hole

6111A: Activity Space

6111B: keyhole

6112: perforation

6113: Groove

6114: avoidance hole

6115: Fastening slot

612: lock piece

62: Circuit components

621: circuit board

622: sensor

623: lock

OD: outer diameter

ID: inner diameter

H: Spacing

S: Gap

Figure 1 shows a schematic diagram of the motor of the present invention.

FIG. 2 is a schematic cross-sectional view of the motor of the present invention.

FIG. 3 is a partially exploded schematic view of the position sensing device of the motor of the present invention.

FIG. 4 is an exploded schematic view of the magnet module of the motor of the present invention.

FIG. 5 is a schematic cross-sectional view of the connecting seat of the motor of the present invention.

FIG. 6 is a partially exploded schematic view of the magnet module of the motor of the present invention.

FIG. 7 is a schematic diagram of the magnet fixing seat of the motor of the present invention.

FIG. 8 is a schematic cross-sectional view of the magnet fixing base of the motor of the present invention.

FIG. 9 is a partially enlarged schematic diagram of FIG. 2 .

FIG. 10 is a schematic diagram of the fixing seat of the motor of the present invention.

FIG. 11 is an exploded schematic diagram of the fixing seat of the motor of the present invention and the motor body provided with the magnet module.

FIG. 12 is a partially exploded schematic diagram of the motor body, magnet module and circuit components of the motor of the present invention.

Figure 13 shows a top view of the motor of the present invention.

FIG. 14 is a schematic partial cross-sectional view of section line XIV shown in FIG. 1 .

FIG. 15 is a schematic partial cross-sectional view of the motor of the present invention.

In the following description, if it is pointed out that please refer to the specific drawing or as shown in the specific drawing, it is only used to emphasize the subsequent description, and most of the relevant content mentioned appears in the specific drawing, It is not intended, however, to limit the ensuing description to only those particular drawings referred to.

Please refer to FIGS. 1 to 4 together. FIG. 1 is a schematic diagram of the motor of the present invention, FIG. 2 is a schematic cross-sectional view of the motor of the present invention, and FIG. 3 is a partially exploded schematic diagram of the position sensing device of the motor of the present invention. , FIG. 4 shows an exploded view of the magnet module of the motor of the present invention. The motor A of the present invention includes a motor body A1 and a position sensing device A2. The motor body A1 includes an outer shell 1 , a stator 2 and a rotor 3 . The outer shell 1 includes a shell main body 10 and an end cover 11. The shell main body 10 includes a ring side wall 101 and a bottom wall 102. The ring side wall 101 is formed by extending from the periphery of the bottom wall 102 to one side, and the ring side wall 101 and the bottom wall 102 are in common An accommodating space 10A is formed, and the accommodating space 10A is used for accommodating the stator 2 and the rotor 3 . The bottom wall 102 is formed with an opening 1021 , and the opening 1021 is disposed through the bottom wall 102 . A bearing 4A is disposed on the inner side of the bottom wall 102 , and the bearing 4A is located in the accommodating space 10A and is not exposed outside the opening 1021 . The end cover 11 is detachably disposed on the end of the shell body 10 opposite to the bottom wall 102 . The inner side of the end cover 11 is provided with another bearing 4B.

The position sensing device A2 is detachably fixedly arranged on the outside of the bottom wall 102, and the position sensing device A2 is not connected with the bearing 4A located inside the bottom wall 102. Therefore, when disassembling the position sensing device A2, no need Any action of disassembling and assembling the bearing 4A can effectively prevent the bearing 4A from being damaged during the process of disassembling and assembling the position sensing device A2 by relevant personnel.

Specifically, in the existing common motors equipped with a position sensing device, because the position sensing device is installed in the motor, when disassembling the position sensing device, the relevant personnel must disassemble and assemble the bearing of the motor. , will easily lead to the deviation of the relevant components inside the bearing problem, and this deviation problem may cause the motor to run unsmoothly, or even prevent the motor from running normally.

The stator 2 is fixed inside the case main body 10 . The rotor 3 includes a mandrel 30 , and the two ends of the mandrel 30 are respectively connected to two bearings 4A, 4B located in the outer casing 1 . One end of the mandrel 30 is formed with a first connecting structure 301 and a locking hole 302 , and the first connecting structure 301 and the locking hole 302 are exposed through the opening 1021 . For example, the first connection structure 301 may be composed of a plurality of grooves with different inner diameters, but it is not limited thereto. The locking hole 302 is concavely formed at one end of the mandrel 30 along a central axis of the mandrel 30 . The lock hole 302 is, for example, a screw hole.

The position sensing device A2 includes: a magnet module 5 and a detection module 6 . The magnet module 5 is detachably connected to the mandrel 30 through the opening 1021 of the bottom wall 102 , and the magnet module 5 can rotate together with the mandrel 30 . The detection module 6 is detachably arranged on the outside of the bottom wall 102, and the detection module 6 is used to cooperate with the magnet module 5, so as to generate a corresponding position sensing signal according to the rotation status of the spindle 30 .

Please refer to FIGS. 4 to 9 together. FIG. 5 shows a schematic cross-sectional view of the connecting seat of the motor of the present invention, FIG. 6 shows a partial exploded view of the magnet module of the motor of the present invention, and FIG. 7 shows the motor of the present invention. 8 shows a schematic cross-sectional view of the magnet fixing seat of the motor of the present invention, and FIG. 9 shows a partially enlarged schematic view of FIG. 2 .

More specifically, the magnet module 5 includes a connecting component 51 and an induction magnet 52 . The connecting component 51 includes a connecting base 511 , a locking member 512 and a magnet fixing base 513 . One end of the connecting base 511 includes a second connecting structure 5111 and a locking hole 5112 . The shape of the second connection structure 5111 corresponds to the shape of the first connection structure 301 of the mandrel 30 , and the connection seat 511 can engage with the first connection structure 301 of the mandrel 30 through the second connection structure 5111 . Through the design of the first connection structure 301 and the second connection structure 5111, the connection position between the connection seat 511 and the mandrel 30 can be corrected, thereby increasing the connection The concentricity between the socket 511 and the spindle 30 can ensure that the magnet module 5 can rotate stably with the spindle 30 . The locking hole 5112 of the connecting seat 511 is disposed through the connecting seat 511 .

When the connecting seat 511 engages with the first connecting structure 301 of the mandrel 30 through the second connecting structure 5111, the locking hole 5112 of the connecting seat 511 will communicate with the locking hole 5112 of the mandrel 30, and the locking member 512 can The lock hole 5112 of the connection base 511 and the lock hole 302 of the mandrel 30 are mutually locked, so that the connection base 511 and the mandrel 30 are fixed to each other. That is to say, the connecting seat 511 is detachably fixed on one end of the spindle 30 through the locking member 512 , and the connecting assembly 51 can rotate with the spindle 30 accordingly.

The connecting seat 511 also includes a receiving slot 5113 . The receiving groove 5113 is formed by indenting the end of the connecting seat 511 opposite to the locking hole 5112 , and the receiving groove 5113 and the locking hole 5112 communicate with each other. Both the receiving groove 5113 and the locking hole 5112 are located on the same axis. The magnet fixing base 513 is detachably engaged in the slot 5113 . When the magnet fixing seat 513 is disposed in the cavity 5113 , the lock hole 5112 will be covered by the magnet fixing seat 513 .

The magnet fixing base 513 includes a fixing groove 5131 and an operation hole 5132 , and the induction magnet 52 is detachably engaged in the fixing groove 5131 . The operation hole 5132 is disposed through the magnet fixing seat 513 , and the operation hole 5132 communicates with the fixing groove 5131 . When the induction magnet 52 is fixed in the magnet fixing seat 513 , the user may, for example, insert a related tool into the operation hole 5132 to push against the induction magnet 52 so as to make the induction magnet 52 leave the magnet fixing seat 513 .

As shown in Figure 6 and Figure 8, in one of the specific embodiments, the two ends of the magnet holder 513 are respectively defined as a first end 513A and a second end 513B, and the magnet holder 513 is recessed from the first end 513A A fixing groove 5131 is formed, the outer diameter OD of the magnet fixing seat 513 gradually decreases from the first end 513A to the second end 513B, and the inner diameter ID of the fixing groove 5131 gradually increases from the first end 513A to the second end 513B, and the magnet fixing seat The periphery of 513 has a plurality of external auxiliary structures 5133, and the magnet holder 513 can be engaged and fixed in the housing groove 5113 of the magnet holder 513 through a plurality of outer auxiliary structures 5133, and the magnet is fixed The seat 513 also has a plurality of inner auxiliary structures 5134 in the fixing groove 5131 , and the plurality of inner auxiliary structures 5134 are used to engage and fix the induction magnet 52 in the fixing groove 5131 .

Through the design of a plurality of outer auxiliary structures 5133 and a plurality of inner auxiliary structures 5134, the magnet fixing seat 513 can still be firmly engaged with the connecting seat 511 without using glue, and the induction magnet can be 52 is firmly engaged with the magnet fixing seat 513 without using glue.

Since the magnet fixing base 513 is not fixed to the connection base 511 with glue, and the induction magnet 52 is not fixed to the magnet fixing base 513 with glue, the relevant personnel can replace the magnet fixing base 513 and the induction magnet with different sizes and magnetic forces according to requirements. Magnet 52. In addition, when the motor A fails or is damaged, relevant personnel can also remove the induction magnet 52 through a simple operation to replace the induction magnet 52 , or reuse the induction magnet 52 .

As shown in FIG. 5 and FIG. 9 , in a preferred embodiment, the connecting seat 511 may further include a through hole 5114 on one side. The side through hole 5114 is formed by indenting the periphery of the connection base 511 , and the side through hole 5114 penetrates through the side wall of the connection base 511 , and the side through hole 5114 communicates with the container 5113 . When the magnet fixing seat 513 is engaged in the receiving groove 5113 , a part of a bottom 513C of the magnet fixing seat 513 can communicate with the outside through the side through hole 5114 . Through the design of the side through hole 5114, when the magnet module 5 and the mandrel 30 are fixed to each other, the relevant personnel can make an external tool enter the side through hole 5114 to push against the bottom 513C of the magnet fixing seat 513, thereby fixing the magnet The seat 513 pushes out of the connecting seat 511 . When the magnet fixing base 513 is pushed out of the connecting base 511 , the locking member 512 will be exposed, and the user can operate the locking member 512 to separate the connecting base 511 from the mandrel 30 .

It should be noted that in this embodiment, the connecting base 511 includes a single side through hole 5114 as an example, but the number of side through holes 5114 included in the connecting base 511 is not limited thereto. In different embodiments, The connection seat 511 may also include two side through holes 5114 facing each other.

Please refer to Fig. 2 and Fig. 3 again, in practical applications, the induction magnet 52 can be a cylindrical structure, and when the magnet module 5 and the mandrel 30 are fixed to each other, the induction magnet 52 and the mandrel 30 have a common center The axis, that is, the spindle 30 and the induction magnet 52 are on the same axis.

It should be emphasized that in the above description, the connection assembly 51 also includes the magnet holder 513 as an example, but in different embodiments, the connection assembly 51 may also not include the magnet holder 513, and the induction magnet 52 It may be directly fixed in the connecting seat 511 .

Please refer to Fig. 3, Fig. 10 to Fig. 14 together, Fig. 10 is a schematic diagram of the fixing base of the motor of the present invention, and Fig. 11 is an exploded schematic diagram of the fixing base of the motor of the present invention and the motor body provided with the magnet module , FIG. 12 shows a partial exploded view of the motor body, magnet module and circuit assembly of the motor of the present invention, FIG. 13 shows a top view of the motor of the present invention, and FIG. 14 shows a partial cross-sectional view of the motor of the present invention. The detection module 6 includes a base component 61 and a circuit component 62 . The base assembly 61 is detachably fixed on one side of the outer casing 1 having the opening 1021 . The circuit assembly 62 is detachably fixed on the base assembly 61 .

The base assembly 61 includes a fixing base 611 and a plurality of locking pieces 612 . The fixing seat 611 includes a plurality of fixing holes 6111 . The bottom wall 102 has a plurality of locking holes 1022 corresponding to the plurality of fixing holes 6111 , and the plurality of locking elements 612 can pass through the plurality of fixing holes 6111 to lock with the plurality of locking holes 1022 of the bottom wall 102 .

The fixing base 611 also includes a through hole 6112 and a groove 6113 . The through hole 6112 is provided through the fixing seat 611 , and the groove 6113 communicates with the through hole 6112 . The through hole 6112 and the groove 6113 are used for accommodating the magnet module 5 . When the magnet module 5 and the mandrel 30 are fixed to each other, and the fixing base 611 is fixed to the bottom wall 102 of the housing 1 , the magnet module 5 will pass through the through hole 6112 , and the magnet module 5 will be located in the groove 6113 .

In practical applications, one side of the fixing seat 611 may also have a evacuation hole 6114, the evasion hole 6114 communicates with the wire hole 1023 of the bottom wall 102 of the outer casing 1, and the relevant wires inside the motor A can pass through the wire hole 1023 and escape hole 6114 are connected with the outside.

The circuit assembly 62 includes a circuit board 621 , a sensor 622 and a plurality of locking pieces 623 . The circuit board 621 is detachably fixed on the fixing base 611 , and the sensor 622 is disposed on a side of the circuit board 621 facing the groove 6113 . When the position sensing device A2 is fixedly arranged on one end of the outer casing 1 of the motor A, the sensor 622 will be arranged facing the induction magnet 52, so that when the spindle 30 rotates, the connecting seat 511 and the induction magnet 52 will follow the spindle. 30 rotates, and the sensor 622 senses the induction magnet 52 to generate a position sensing signal correspondingly.

As shown in FIGS. 12 to 14 , in one practical application, the fixing base 611 further includes a fastening groove 6115 , the depth of the fastening groove 6115 is smaller than the depth of the groove 6113 , and the circuit board 621 is located in the fastening groove 6115 . The fixing slot 6115 communicates with the plurality of fixing holes 6111 , and when the circuit board 621 is fixed in the fixing slot 6115 , a part of each fixing hole 6111 is covered by the circuit board 621 .

When the circuit board 621 is fixed in the clamping groove 6115, a gap S in each fixing hole 6111 not covered by the circuit board 621 can enable a tool (such as a screwdriver) to extend into the fixing hole 6111, so that the locking member 612 is no longer in contact with the fixing hole 6115. The locking holes 1022 of the bottom wall 102 of the outer casing 1 are mutually locked, and a movable space 6111A in the fixing hole 6111 can accommodate a part of the locking member 612 that is no longer interlocked with the outer casing 1, so that the fixing seat 611 Can be separated from the outer casing 1 .

That is to say, the circuit board 621 will not completely cover each fixing hole 6111, and the user can insert a screwdriver into the unshielded gap S of the fixing hole 6111 to operate the locking piece 612, so that the locking piece 612 is no longer in contact with the fixing hole 6111. The bottom walls 102 are locked to each other. When each locking member 612 is no longer mutually locked with the bottom wall 102, each locking member 612 will be restricted by the circuit board 621 and cannot leave the fixing hole 6111, thereby effectively avoiding the problem that the locking member 612 is lost .

As shown in FIG. 14 , in practical applications, each fixing hole 6111 may include the movable space 6111A and a locking hole 6111B, and when the locking member 612 is locked with the bottom wall 102, a part of the locking member 612 may be The locking holes 6111B are mutually locked, and a part of the locking member 612 (for example The head of the screw) is correspondingly located in the activity space 6111A. In different embodiments, the lock hole 6111B can also be a through hole, not limited to a screw hole.

As shown in FIG. 3 and FIG. 15 , it should be emphasized that the motor A of the present invention allows related personnel to adjust the distance H between the sensor 622 and the induction magnet 52 in various ways. For example, relevant personnel can adjust the spacing H by removing the circuit board 621 to replace different circuit boards 621 and sensors 622; The requirement of adjusting the spacing H; or, the relevant personnel can meet the requirement of adjusting the spacing H by replacing the magnet holder 513 .

To sum up, the motor of the present invention allows relevant personnel to disassemble and assemble the position sensing device without dismantling the motor body, especially without disassembling the bearing inside the motor body. Moreover, the motor of the present invention can also allow relevant personnel to adjust the distance between the inductor and the induction magnet by simply replacing at least one of the induction magnet, the magnet holder, the holder, and the circuit board according to the requirements.

The above descriptions are only preferred feasible embodiments of the present invention, and do not limit the patent scope of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the scope of protection of the present invention. .

A: motor

A1: Motor body

1021: opening

1023: wire hole

A2: Position sensing device

5: Magnet module

51: Connection components

511: connection seat

512: lock piece

513: Magnet holder

52: induction magnet

61: seat assembly

62: Circuit components

611: fixed seat

623: lock

6: Detection module

612: lock piece

621: circuit board

4A: Bearing

Claims (11)

A motor comprising: A motor body comprising: certain stator; a rotor comprising a mandrel having a first connecting structure at one end thereof; An outer casing, in which the stator and the rotor are arranged, and one end of the outer casing has an opening, and the first connection structure is exposed through the opening; A position sensing device comprising: A magnet module, which includes: A connecting component, which includes a connecting base and a locking piece, the connecting base includes a second connecting structure, the second connecting structure is used to engage with the first connecting structure, and the locking piece can detachably fixing the connecting seat and the mandrel to each other, and the connecting assembly can rotate with the mandrel; an induction magnet, which is fixed on the connecting seat; A detection module, which includes: a seat assembly, which is detachably fixed to the side of the outer casing having the opening; A circuit assembly, which is detachably fixed to the base assembly, and a sensor of the circuit assembly is arranged facing the induction magnet; Wherein, when the mandrel rotates, the connecting base and the induction magnet will rotate with the mandrel, and the sensor will sense the induction magnet to generate a corresponding position sensing signal . The motor according to claim 1, wherein the connection assembly further includes a magnet fixing seat, the connection seat has the second connection structure, and the connection seat is connected to the spindle through the locking member fixed, the connection base includes a slot, the magnet fixing base is detachably engaged in the slot, the magnet fixing base includes a fixing slot and an operation hole, and the induction magnet is detachable The snap fit is arranged in the fixing groove, the operation hole runs through the magnet fixing seat, and the operation hole communicates with the fixing groove. The motor according to claim 2, wherein the connecting base further includes a side through hole, the side through hole communicates with the container, and a part of a bottom of the magnet fixing base can pass through the The side through hole communicates with the outside, and an external tool can pass through the side through hole to abut against the bottom. The motor according to claim 2, wherein the two ends of the magnet fixing seat are respectively defined as a first end and a second end, and the first end of the magnet fixing seat is recessed to form the fixing groove , the outer diameter of the magnet fixing seat gradually decreases from the first end to the second end, the inner diameter of the fixing groove gradually increases from the first end to the second end, and the magnet The periphery of the fixing seat has a plurality of external auxiliary structures, and the magnet fixing seat can be engaged and fixed in the accommodating groove through a plurality of the outer auxiliary structures, and the magnet fixing seat also has a plurality of outer auxiliary structures in the fixing groove. The internal auxiliary structure, a plurality of the internal auxiliary structures are used to engage and fix the induction magnet in the fixing groove. The motor according to claim 2, wherein the induction magnet is cylindrical, and the induction magnet and the spindle have a common central axis. The motor according to claim 1, wherein the base assembly includes a fixing seat, the fixing seat is detachably fixed to one end of the outer casing, the fixing seat includes a through hole and a groove, the The through hole is set through the fixing seat, and the groove communicates with the through hole; the magnet module is passed through the through hole, and the magnet module is located in the groove; the circuit assembly is also A circuit board is included, the circuit board is detachably fixed on the fixing seat, and the sensor is arranged on a side of the circuit board facing the groove. The motor according to claim 6, wherein the fixing seat further includes a fastening groove, the depth of the fastening groove is smaller than the depth of the groove, the circuit board is located in the fastening groove, and The fixing seat includes a plurality of fixing holes, and the plurality of fixing holes are used to cooperate with a plurality of the locking pieces, so that the fixing seat is fixed on one side of the outer shell; The two fixing holes communicate with each other, and when the circuit board is fixed in the fastening groove, a part of each fixing hole is covered by the circuit board. The motor according to claim 7, wherein when the circuit board is fixed in the fastening slot, a gap in each of the fixing holes not covered by the circuit board allows a tool to be inserted into the fixing hole so that the locking piece is no longer interlocked with the outer casing, and a movable space in the fixing hole can accommodate a part of the locking piece that is no longer interlocked with the outer casing so that the fixing seat can be separated from the outer casing. The motor as claimed in claim 6, wherein one side of the fixing base has an escape hole, and the escape hole communicates with a line hole of the outer shell. The motor according to claim 1, wherein a bearing is provided at both ends of the outer casing, and the two ends of the spindle are respectively connected to the two bearings, and the bearings are located inside the outer casing , and the bearing is not exposed outside the opening. The motor according to claim 1, wherein the outer casing includes a casing main body and an end cover, the casing main body includes a ring side wall and a bottom wall, and the ring side wall extends from the periphery of the bottom wall to one side Formed, the bottom wall is formed with the opening, the position sensing device is detachably fixed on the bottom wall; the end cover is detachably arranged on the end of the shell body opposite to the bottom wall .

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