CN217388364U - Slender toothbrush motor - Google Patents

Abstract

The utility model provides a slender toothbrush motor, including shell, stator core, coil winding, motor shaft and permanent magnetism part, stator core includes wire winding portion and the magnetic conduction arm that extends from wire winding portion, and coil winding winds on wire winding portion, and coil winding and wire winding portion distribute in the tip department of motor shaft along the axial of motor shaft, and permanent magnetism part and magnetic conduction arm all extend along the axial straightness of motor shaft, and the magnetic conduction arm distributes in the periphery side of permanent magnetism part along the radial of motor shaft; the stator core is formed by radially laminating and riveting a plurality of silicon steel sheets along the motor shaft, and the laminating and riveting direction of the silicon steel sheets is vertical to the extending direction of the winding part and the extending direction of the magnetic conduction arm part. The present application can reduce the sectional size of the toothbrush motor, so that the toothbrush motor can be easily made into a slim type, and further, the present application can be preferably applied to an electric toothbrush having a slim shape, having a wide inner space in a length direction, but having a narrow inner space in a width direction, and thus, the applicability is improved.

Description

Slender toothbrush motor

Technical Field

The utility model relates to a motor, in particular to a slender toothbrush motor.

Background

The electric toothbrush mainly comprises a motor (namely a motor) and a brush head, wherein the brush head generates high-frequency vibration through the rapid operation of the motor, so that toothpaste is instantly decomposed into fine foam to deeply clean teeth gaps; meanwhile, the vibration of the brush hair on the brush head can promote the blood circulation in the oral cavity, and has a certain massage effect on the gum tissue. Thus, the motor is a major component of the electric toothbrush.

Further, the motor for the electric toothbrush at present mainly includes a stator portion and a rotor portion; the stator part comprises a shell, a stator core and a coil winding, wherein the stator core and the coil winding are fixed on the shell; the rotor part comprises a motor shaft rotatably supported in the housing through a bearing, and a permanent magnet fixed on the outer surface of the motor shaft; the stator core is matched with the permanent magnet. The coil winding may be a single coil structure disposed on one side of the motor shaft or a double coil structure disposed on both sides of the motor shaft. However, in either a single coil structure or a double coil structure, the coil windings and the stator core are distributed on the outer peripheral side of the motor shaft along the radial direction of the motor shaft, that is, the coil windings and the stator core are vertically distributed with respect to the motor shaft, so that the coil windings and the stator core occupy the cross-sectional space together, and the cross-sectional size of the motor for the electric toothbrush is difficult to be reduced, and thus the motor is difficult to be applied to the electric toothbrush having a slim shape and an abundant inner space in the length direction.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an elongated toothbrush motor with a small cross-sectional size.

In order to achieve the above object, the present invention provides an elongated toothbrush motor, including a housing, a stator core and a coil winding both fixed to the housing, a motor shaft rotatably supported in the housing, and a permanent magnet member fixed to the motor shaft, the stator core including a winding portion and a magnetic conductive arm portion extending from the winding portion, the coil winding being wound on the winding portion, and the coil winding and the winding portion being distributed at an end portion of the motor shaft in an axial direction of the motor shaft, the permanent magnet member and the magnetic conductive arm portion both extending straightly in the axial direction of the motor shaft, the magnetic conductive arm portion being distributed at an outer peripheral side of the permanent magnet member in a radial direction of the motor shaft; the stator core is formed by radially laminating and riveting a plurality of silicon steel sheets along the motor shaft, the laminating and riveting direction of the silicon steel sheets is perpendicular to the extending direction of the winding portion and the extending direction of the magnetic conduction arm portion, and an insulating layer is arranged on the outer surface of each silicon steel sheet.

Furthermore, the silicon steel sheets are U-shaped silicon steel sheets, and the stator core formed by stacking and riveting the U-shaped silicon steel sheets has two magnetic conductive arm parts which are symmetrically distributed in the radial direction of the motor shaft.

Preferably, the U-shaped silicon steel sheet is of a sectional structure and comprises two L-shaped sections which are symmetrically distributed in the radial direction of the motor shaft.

Preferably, the U-shaped silicon steel sheet is of a sectional structure and comprises three sections of linear sections.

Preferably, the U-shaped silicon steel sheet is of a sectional structure and comprises a linear section and an L-shaped section.

Furthermore, the slender toothbrush motor also comprises a magnetizer fixed on the periphery of the motor shaft, and the magnetizer is matched with the permanent magnet part; the magnetizer, the permanent magnet part and the magnetic conduction arm part are sequentially distributed inside and outside along the radial direction of the motor shaft; and two cutting surfaces which are respectively flush with the circumferential edges at two sides of the permanent magnet part are arranged on the peripheral surface of the magnetizer.

Further, the housing includes a main housing and an end housing that are axially distributed side by side along a motor shaft, the motor shaft is rotatably supported in the main housing by a first bearing and a second bearing, respectively, the permanent magnet member is located in the main housing, and the stator core and the coil winding are fixed to the end housing.

Further, the first mounting groove of holding first bearing and the second mounting groove of holding second bearing are seted up respectively to the both ends of main casing body, the inner circle of first bearing and motor shaft are fixed continuous and the first bearing of shelves is only ended to the inner tank bottom of first mounting groove, the inner circle of second bearing and motor shaft are fixed continuous and the inner tank bottom of second mounting groove ends the shelves second bearing.

Further, the end portion shell comprises a shell bottom and shell side wing portions fixed at two ends of the shell bottom, a first groove for accommodating the winding portion is formed in the shell bottom, a second groove for accommodating the magnetic conduction arm portion is formed in the shell side wing portions, and the first groove is communicated with the second groove.

As described above, the elongated toothbrush motor according to the present invention has the following advantageous effects:

in this application, distribute the coil winding and stator core's wire winding portion at the tip of motor shaft along the axial of motor shaft to make permanent magnetism part and magnetic conduction arm portion all extend along the axial of motor shaft is straight, can reduce the cross sectional dimension of this toothbrush motor from this, make the toothbrush motor make slenderness easily, and then can be applicable to elongated appearance better, have abundant inner space in length direction, but the electric toothbrush that inner space is comparatively nervous in width direction, improve the suitability greatly.

Drawings

FIG. 1 is a schematic view of the construction of an elongated toothbrush motor of the present application.

Fig. 2 is a cross-sectional view of an elongated toothbrush motor of the present application.

Fig. 3 is a schematic view of the elongated toothbrush motor of the present application with the housing omitted.

Fig. 4 is a top view of fig. 3.

Fig. 5 is a front view of fig. 3.

Fig. 6 and 7 are schematic structural views of the end shell in different viewing angles in the present application.

Fig. 8 is a schematic structural diagram of a stator core according to the present application.

FIG. 9 is a schematic structural view of the silicon steel sheet of FIG. 8.

FIGS. 10a to 10d show a preferred embodiment of the silicon steel sheet in the present application.

Description of the element reference numerals

10 outer casing

11 main casing

111 first mounting groove

112 second mounting groove

12 end shell

121 bottom of the housing

122 side wing part of the shell

123 first groove

124 second groove

20 stator core

21 winding part

22 magnetic conductive arm part

23 silicon steel sheet

231L-shaped segment

232 straight line segment

30 coil winding

40 Motor shaft

50 permanent magnet component

60 first bearing

70 second bearing

80 magnetizer

81 cut surface

Detailed Description

The following description is provided for illustrative purposes, and other advantages and features of the present invention will become apparent to those skilled in the art from the following detailed description.

It should be understood that the drawings of the present application are only used to match the contents disclosed in the specification, so as to be known and read by those skilled in the art, and not to limit the practical limitations of the present invention, so that the present application does not have any technical significance, and any modification of the structure, change of the ratio relationship, or adjustment of the size should still fall within the scope of the present application without affecting the function and the achievable purpose of the present application. In addition, the terms such as "upper", "lower", "left", "right", "middle", etc. used in the present specification are only for convenience of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms should be construed as the scope of the present invention without substantial technical changes.

An elongated toothbrush motor for an electric toothbrush is provided. As shown in fig. 1 to 5, the present application relates to an elongated toothbrush motor including a housing 10, a stator core 20 and a coil winding 30 both fixed to the housing 10, a motor shaft 40 rotatably supported in the housing 10 by a bearing, and a permanent magnet part 50 fixedly distributed on the outer circumference of the motor shaft 40, the motor shaft 40 being made of a magnetically conductive material. For convenience of description, in the present embodiment, as shown in fig. 1, an axial direction of the motor shaft 40 is defined as a Z direction, and two radial directions, in which the motor shaft 40 is orthogonal to the Z direction, are defined as an X direction and a Y direction, respectively; the Z direction is a front-rear direction, the X direction is a left-right direction, and the Y direction is an up-down direction.

Further, as shown in fig. 1 to 5, the stator core 20 includes a winding portion 21, and a magnetic conductive arm portion 22 extending from the winding portion 21; wherein, winding portion 21 extends straight in the radial direction X of motor shaft 40, coil winding 30 is wound on winding portion 21, and coil winding 30 and winding portion 21 are distributed at the end of motor shaft 40 in the axial direction Z of motor shaft 40; the magnetic arm 22 is engaged with the permanent magnet member 50, and both the permanent magnet member 50 and the magnetic arm 22 extend straight in the axial direction Z of the motor shaft 40, and the magnetic arm 22 is distributed on the outer peripheral side of the permanent magnet member 50 in the radial direction X of the motor shaft 40. Further, as shown in fig. 8 and 9, the stator core 20 is formed by laminating a plurality of silicon steel sheets 23 in the radial direction Y of the motor shaft 40, such that the laminating direction of the silicon steel sheets 23 is perpendicular to both the extending direction of the winding portion 21 and the extending direction of the magnetic arm portion 22, and an insulating layer is disposed on the outer surface of each silicon steel sheet 23.

When the elongated toothbrush motor is operated, an alternating current is applied to the coil winding 30, a magnetic circuit is generated in the winding portion 21 of the stator core 20, and the magnetic circuit is conducted to the magnetic conductive arm portion 22, as shown in fig. 5; the magnetic flux generated by the magnetic arm 22 interacts with the permanent magnet 50 to convert the electric energy into mechanical energy, so as to drive the motor shaft 40 to swing, and the brush head of the electric toothbrush is fixed on the motor shaft 40, so that the motor shaft 40 drives the brush head of the electric toothbrush to swing rapidly. In particular, in the present invention, the coil winding 30 and the winding portion 21 are distributed at the end of the motor shaft 40 in the axial direction of the motor shaft 40, but not at the outer circumferential side of the motor shaft 40 in the radial direction of the motor shaft 40 as in the prior art, and the permanent magnet member 50 and the magnetic arm portion 22 are combined to extend straight in the axial direction of the motor shaft 40, so that the sectional size of the toothbrush motor can be effectively reduced, the toothbrush motor can be easily made slim, and the toothbrush motor can be preferably applied to an electric toothbrush having a slim outer shape, a wide inner space in the longitudinal direction, and a tight inner space in the width direction, and the applicability of the toothbrush motor can be greatly improved. Meanwhile, as shown in fig. 5 and 8, the magnetic flux direction in the stator core 20 is an X direction extending along the winding portion 21 and a Z direction extending along the magnetic conductive arm portion 22, and the stacking and riveting direction of the plurality of silicon steel sheets 23 constituting the stator core 20 is a Y direction, so that the stacking and riveting direction of the silicon steel sheets 23 is perpendicular to the magnetic flux direction in the stator core 20, and the silicon steel sheets 23 are combined to be a thin sheet-like structure with an insulating layer coated on the surface, so that the eddy current formed in the stator core 20 can be limited in a thin sheet-like space, the eddy current loss of the stator core 20 is greatly reduced, and the performance of the motor is improved.

Further, in the embodiment shown in fig. 1 to 5, only one coil winding 30 is provided in the slim toothbrush motor, and the coil winding 30 has a single-side coil structure, that is, both the coil winding 30 and the winding portion 21 are distributed at the rear end of the motor shaft 40 in the axial direction of the motor shaft 40. A pair of permanent magnet members 50 are arranged; accordingly, the pair of magnetic arm portions 22 of the stator core 20 is also arranged in one-to-one correspondence with the permanent magnet members 50, and therefore, the stator core 20 has a substantially U-shape with two magnetic arm portions 22 symmetrically distributed in the radial direction X of the motor shaft 40. Preferably, as shown in fig. 3 and 4, each permanent magnet member 50 is bipolar, having an N pole and an S pole; namely: each permanent magnet part 50 comprises two permanent magnets with different polarities, and the two permanent magnets forming each permanent magnet part 50 are closely arranged along the circumferential direction of the motor shaft 40 and extend along the axial direction of the motor shaft 40, so that the permanent magnets are in a slender strip-shaped structure; there is a gap between the two permanent magnet parts 50 connected in the circumferential direction of the motor shaft 40.

Further, as shown in fig. 8 and 9, the stator core 20 is substantially U-shaped, so the silicon steel sheets 23 laminated and riveted to form the stator core 20 are correspondingly U-shaped silicon steel sheets. In order to facilitate the winding of the coil winding 30, the U-shaped stator core 20 is formed in a sectional structure, and accordingly, the U-shaped silicon steel sheets (i.e., the silicon steel sheets 23) are also formed in a sectional structure. Based on this, the U-shaped silicon steel sheet of the sectional structure has several preferred embodiments as follows.

In the first embodiment of the U-shaped silicon steel sheet, as shown in fig. 10a, the U-shaped silicon steel sheet includes two L-shaped segments 231 symmetrically distributed along the radial direction X of the motor shaft, a portion of each L-shaped segment 231 extending along the direction X from left to right constitutes a winding portion 21 of the stator core 20, and a portion of each L-shaped segment 231 extending along the direction Z from front to back constitutes a magnetic conductive arm portion 22 of the stator core 20.

In the second embodiment of the U-shaped silicon steel sheet, as shown in fig. 10b, the U-shaped silicon steel sheet includes a linear section 232 and an L-shaped section 231 which are arranged side by side along the X direction, the linear section 232 extends forward and backward along the Z direction to form one magnetic conductive arm 22 of the stator core 20, a portion of the L-shaped section 231 extending leftward and rightward along the X direction forms the winding portion 21 of the stator core 20, and a portion of the L-shaped section 231 extending forward and backward along the Z direction forms the other magnetic conductive arm 22 of the stator core 20.

In the third embodiment of the U-shaped silicon steel sheet, as shown in fig. 10c, the U-shaped silicon steel sheet includes three linear segments 232, wherein one linear segment 232 extends left and right along the X direction to form the winding portion 21 of the stator core 20, and the other two linear segments 232 extend front and back along the Z direction to form the two magnetic conductive arm portions 22 of the stator core 20. Further, the two linear segments 232 extending forward and backward in the Z direction extend to the front end faces of the linear segments 232 extending leftward and rightward in the X direction, and they are in surface contact with each other in the forward and backward directions.

In the fourth embodiment of the U-shaped silicon steel sheet, as shown in fig. 10d, the U-shaped silicon steel sheet includes three linear segments 232, which are substantially the same as the third embodiment of the U-shaped silicon steel sheet, and the difference is that: in the fourth embodiment of the U-shaped silicon steel sheet, the rear ends of the two linear sections 232 extending forward and backward in the Z direction are flush with the rear ends of the linear sections 232 extending leftward and rightward in the X direction, and the two linear sections are in contact fit with each other in the left-right direction.

Further, as shown in fig. 2 to 4, the slim toothbrush motor further includes a magnetic conductor 80 fixed to an outer periphery of the motor shaft 40, the magnetic conductor 80 being engaged with the permanent magnet part 50, the magnetic conductor 80 extending axially in a Z direction of the motor shaft 40; the magnetizer 80, the permanent magnet part 50 and the magnetic arm part 22 are sequentially distributed inside and outside in the radial direction of the motor shaft 40. Moreover, the outer peripheral surface of the magnetizer 80 is provided with two cutting surfaces 81 which are respectively flush with the peripheral edges of the two sides of the permanent magnet part 50, so that the magnetizer 80 is prevented from protruding from the matching area of the non-permanent magnet part 50 and occupying the cross section size.

Further, as shown in fig. 1 and 2, the housing 10 includes a main housing 11 and an end housing 12 which are arranged side by side in the front-rear direction in the axial direction of the motor shaft 40, the motor shaft 40 is rotatably supported in the main housing 11 by a first bearing 60 and a second bearing 70, respectively, the permanent magnet member 50 and the magnetic conductor 80 are both located in the main housing 11, and the coil windings 30 and the stator core 20 are both fixed to the end housing 12. Preferably, the main housing 11 and the end housing 12 are integrally molded, so as to reduce cost and facilitate assembly.

Further, the first bearing 60 is distributed at the front end of the main housing 11, and the second bearing 70 is distributed at the rear end of the main housing 11, and the first bearing 60 and the second bearing 70 are used for realizing encapsulation. Specifically, as shown in fig. 2, a first mounting groove 111 for accommodating the first bearing 60 is formed at the front end of the main housing 11, an inner ring of the first bearing 60 is fixedly connected with the motor shaft 40, and a groove bottom stop at the inner end of the first mounting groove 111 forms a backward movement limit for the first bearing 60; the rear end of the main housing 11 is provided with a second mounting groove 112 for accommodating the second bearing 70, the inner ring of the second bearing 70 is fixedly connected with the motor shaft 40, and the groove bottom of the inner end of the second mounting groove 112 stops the second bearing 70 to limit the second bearing 70 to move forward. When the motor shaft 40 and the main housing 11 are assembled, the motor shaft 40 is inserted into the inner hole of the main housing 11, and the first bearing 60 is driven backward into the first mounting groove 111 of the main housing 11 from the front end of the motor shaft 40 until the first bearing 60 abuts against the groove bottom at the rear end of the first mounting groove 111, so that the first bearing 60 presses the main housing 11 inward. Similarly, the second bearing 70 is driven forward from the rear end of the motor shaft 40 into the second mounting groove 112 of the main housing 11 until the second bearing 70 abuts against the groove bottom at the front end of the second mounting groove 112, and the second bearing 70 presses the main housing 11 inward. In this way, after the first bearing 60 and the second bearing 70 are mounted, the first bearing 60 and the second bearing 70 are assembled from the outside of the main housing 11 and the main housing 11 is clamped by the fastening force of the inner race of the first bearing 60 and the motor shaft 40 and the fastening force of the inner race of the second bearing 70 and the motor shaft 40, thereby achieving the packaging of the product. Moreover, when the motor shaft 40 and the main housing 11 are assembled, the first bearing 60 and the second bearing 70 only need to be knocked in from the outer side of the main housing 11 correspondingly, the product is packaged and the bearings are installed for one-step riveting, the installation process is saved, and the assembly efficiency is improved.

Preferably, as shown in fig. 1, 6 and 7, the end housing 12 includes a housing bottom 121 and housing side wing portions 122 fixed at two ends of the housing bottom 121, a first groove 123 is opened in the housing bottom 121 for accommodating the winding portion 21, a second groove 124 is opened in the housing side wing portions 122 for accommodating the magnetic conductive arm portion 22, and the first groove 123 and the second groove 124 are communicated.

Further, the inner race of the first bearing 60 is riveted or adhesively fixed to the motor shaft 40, and the inner race of the second bearing 70 is riveted or adhesively fixed to the motor shaft 40. The end housing 12 is fixedly connected to the stator core 20 by injection molding, so that the end housing 12, the stator core 20 and the coil winding 30 are fixed as an independent prefabricated member, which facilitates winding of the coil winding 30 and processing, assembly and maintenance of the slim toothbrush motor. In addition, a flexible member having elasticity may be provided between the inner end of the first bearing 60 and the groove bottom of the first mounting groove 111, where the flexible member is appropriately compressed to generate a forward force. A resiliently flexible member may also be provided between the inner end of the second bearing 70 and the bottom of the second mounting groove 112 where appropriate compression of the flexible member produces the rearward force. The flexible member is a silicone ring or a gasket made of other elastic materials, so that the first bearing 60 and the second bearing 70 are flexibly supported. In this way, when the outer ring of the first bearing 60 and/or the second bearing 70 is stressed in the front-rear direction Z in a staggered manner, the flexible member can eliminate the Z-directional play of the first bearing 60 and/or the second bearing 70, thereby eliminating the running noise of the first bearing 60 and/or the second bearing 70. In addition, when the motor shaft 40 is subjected to Z-direction impact force when falling, the flexible part can buffer the impact force, and plays a certain protection role.

To sum up, the utility model discloses various shortcomings in the prior art have effectively been overcome and high industry value has.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (9)

1. An elongated toothbrush motor including a housing (10), a stator core (20) and a coil winding (30) both fixed to the housing (10), a motor shaft (40) rotatably supported in the housing (10), and a permanent magnet member (50) fixed to the motor shaft (40), characterized in that: the stator core (20) comprises a winding part (21) and a magnetic conduction arm part (22) extending from the winding part (21), the coil winding (30) is wound on the winding part (21), the coil winding (30) and the winding part (21) are distributed at the end part of the motor shaft (40) along the axial direction of the motor shaft (40), the permanent magnet part (50) and the magnetic conduction arm part (22) both extend straightly along the axial direction of the motor shaft (40), and the magnetic conduction arm part (22) is distributed on the outer peripheral side of the permanent magnet part (50) along the radial direction of the motor shaft (40); the stator core (20) is formed by radially laminating and riveting a plurality of silicon steel sheets (23) along a motor shaft (40), the laminating and riveting direction of the silicon steel sheets (23) is perpendicular to the extending direction of the winding portion (21) and the extending direction of the magnetic conduction arm portion (22), and an insulating layer is arranged on the outer surface of each silicon steel sheet (23).

2. The elongated toothbrush motor of claim 1, wherein: the stator core (20) is characterized in that the silicon steel sheets (23) are U-shaped silicon steel sheets, and a plurality of stator cores (20) formed by stacking and riveting the U-shaped silicon steel sheets are provided with two magnetic conducting arm parts (22) which are symmetrically distributed in the radial direction of the motor shaft (40).

3. The elongated toothbrush motor of claim 2, wherein: the U-shaped silicon steel sheet is of a sectional structure and comprises two L-shaped sections (231) which are symmetrically distributed along the radial direction of the motor shaft (40).

4. The elongated toothbrush motor of claim 2, wherein: the U-shaped silicon steel sheet is of a sectional structure and comprises three linear sections (232).

5. The elongated toothbrush motor of claim 2, wherein: the U-shaped silicon steel sheet is of a sectional structure and comprises a linear section (232) and an L-shaped section (231).

6. The elongated toothbrush motor of claim 1, wherein: the permanent magnet motor is characterized by further comprising a magnetizer (80) fixed on the periphery of the motor shaft (40), wherein the magnetizer (80) is matched with the permanent magnet part (50); the magnetizer (80), the permanent magnet part (50) and the magnetic conduction arm part (22) are sequentially distributed inside and outside along the radial direction of the motor shaft (40); and the peripheral surface of the magnetizer (80) is provided with two cutting surfaces (81) which are respectively flush with the peripheral edges at two sides of the permanent magnet part (50).

7. The elongated toothbrush motor of claim 1, wherein: the housing (10) comprises a main housing (11) and an end housing (12) which are axially distributed side by side along a motor shaft (40), the motor shaft (40) is rotatably supported in the main housing (11) through a first bearing (60) and a second bearing (70), the permanent magnet component (50) is positioned in the main housing (11), and the stator core (20) and the coil winding (30) are fixed on the end housing (12).

8. The elongated toothbrush motor of claim 7, wherein: the bearing is characterized in that two ends of the main shell (11) are respectively provided with a first mounting groove (111) for accommodating the first bearing (60) and a second mounting groove (112) for accommodating the second bearing (70), the inner ring of the first bearing (60) is fixedly connected with the motor shaft (40), the inner bottom of the first mounting groove (111) is provided with a stop first bearing (60), the inner ring of the second bearing (70) is fixedly connected with the motor shaft (40), and the inner bottom of the second mounting groove (112) is provided with a stop second bearing (70).

9. The elongated toothbrush motor of claim 7, wherein: the end portion shell (12) comprises a shell bottom portion (121) and shell side wing portions (122) fixed to two ends of the shell bottom portion (121), a first groove (123) used for accommodating the winding portion (21) is formed in the shell bottom portion (121), a second groove (124) used for accommodating the magnetic conduction arm portion (22) is formed in the shell side wing portions (122), and the first groove (123) is communicated with the second groove (124).

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